ELAEOCARPUS ALKALOIDS

IV.* THE ALKALOIDS OF ELAEOCARPUS SPHAERICUSP

By 8. R. JOHNS,$ J. A. LABIBERTON,~ A. A. SIOUMIS,$ H. SUARES,$

and R. I. WILLING$

[Manuscript received March 17, 19711

Abstract

From the leaves of Elaeocarpus sphaericus (Gaertn.) K. Schum., seven isomeric alkaloids of molecular formula, C16H21NOZ, have been isolated. Two of the alkaloids are identical with (-)-isoelaeocarpiline and (+)-elaeocarpiline previously isolated from E. dolichostylis. Complete structures and absolute configurations have now been determined for the two previously known alkaloids (1) and (6), and for the five new- alkaloids (4), (8), (lo), ( l l ) , and (12), and a study has been made of the products obtained by sodium borohydride reduction of some of the isomeric alkaloids. The previously known Elaeocarpus alkaloids, elaeocarpidine, (&)-elaeo- carpine, and (&)-isoelaeocarpine have also been isolated from E. sphaericus.

Earlier studies on Elaeocarpus polydactylus Schltr., E . dolichostylis Schltr., and E . densiflorus Knuth, all of which are rain-forest species from New Guinea, have shown that the Elaeocarpus alkaloids comprise a new and major class of alkaloids.2-4 These studies have now been exterded to Elaeocarpus sphaericus (Gaertn.) K. Schum., a large tree, widely distributed in New Guinea. The alkaloids of E. sphaericus are an extremely complex mixture and ten alkaloids have been isolated, although not all from the same collection of plant material. The differences in composition observed between the samples of crude alkaloids examined, however, have been relatively slight, and the same major constituents have been common to all samples. E. sphaericus and E . dolichostylis are much more alike in their alkaloid composition than the other species examined, and it seems probable that some of the constituents now reported for E. sphaericus also occur in E . dolichostylis. Another species, E . altisectus Schltr., has not been examined in detail but preliminary results indicate that the alkaloids are similar to those of E. sphaericus and E. dolichostylis, a t least in major constituents.

* Part 111, Aust. J. Chem., 1969, 22, 801. .t The alkaloids of E. sphaericus have been the subject of a preliminary communication.1 f Division of Applied Chemistry, CSIRO, P.O. Box 4331, Melbourne, Vic. 3001.

1 Johns, S. R., Lamberton, J. A., Sioumis, A. A., Suares, H., and Willing, R. I., Chem. Commun., 1970, 804.

2 Johns, S. R., Lamberton, J. A., Sioumis, A. A., and Willing, R. I., Aust. J. Chem., 1969, 22, 775.

3 Johns, S. R., Lamberton, J. A., and Sioumis, A. A,, Aust. J. Chem., 1969, 22, 793. 4 Johns, S. R., Lamberton, J. A., and Sioumis, A. A., Aust. J. Chem., 1969, 22, 801.

Aust. J . Chem., 1971, 24, 1679-94

S. R. JOHNS ET A L

The two stereoisomeric dienone alkaloids, (-)-isoelaeocarpiline and (+)- elaeocarpiline, previously obtained from E. dolichostylis,3 have now been isolated from E. sphaericus, and in addition a further five stereoisomers of these alkaloids have been obtained. The two known aromatic alkaloids, (&)-elaeocarpine and (f )- isoelaeocarpine,z occur as minor constituents, and the indole alkaloid, elaeocarpidine,4 has been obtained from one batch of E. sphaericus. The complex alkaloid mixture undoubtedly contains many other constituents, but these have not been isolated in a pure state.

Complete structures and absolute configurations have now been determined for (-)-isoelaeocarpiline, (+)-elaeocarpiline, and the five new stereoisomers of these alkaloids.

(a) ( -)-Isoelaeocarpiline (1)

The major alkaloid of E. sphaericus has been identified as (-)-isoelaeocarpiline (l), which has previously been reported as the major alkaloid of E. dolichostylis.3 The structure and relative configuration of (-)-isoelaeocarpiline (1) were previously assigned3 from a study of its chemical and spectroscopic properties, and, in particular, it was possible to assign the relative configuration a t the C 16 centre because of the unreactivity of the carbonyl group of (-)-isoelaeocarpiline to sodium borohydride. The absolute configuration of (-)-isoelaeocarpiline, shown in ( l ) , and opposite to that arbitrarily assigned in depicting the relative stereochemistry,3 has now been deter- mined by oxidation of the alkaloid with aqueous potassium permanganate to give a

mixture of acids from which (-)-methylsuccinic acid (2) has been isolated. The asymmetric centre of (2) corresponds to the C 16 asymmetric centre of (-)-isoelaeo- carpiline, and the absolute configuration of the C 16 centre can be assigned from the known absolute configuration of S-(-)-methylsuccinic acid.5 According to the

5 Fredga, A., Jennings, J. P., Klyna, W., Scopes, P. M., Sjoberg, B., and Sjoberg, S., J. chem. Soc., 1965, 3928.

ELAEOCARPUS ALKALOIDS. IV 1681

1682 S. R. JOHNS ET AL.

Cahn, Ingold, Prelog system of nomenclature,6 the absolute configuration of (-)-isoelaeocarpiline can be given as 7R,8S,9S,16S, and corresponding absolute con- figurations can be assigned to (-)-isoelaeocarpine (3) and (-)-13,14-dihydro- isoelaeocarpiline, the products obtained by heating (-)-isoelaeocarpiline with palladium-charcoal in benzene.3

A second alkaloid, (+ )-epiisoelaeocarpiline (4), m.p. 98-100°, [&ID J,- 340°, has been shown to have the molecular formula C16H21N0.2 by elementary analysis and by a molecular ion peak a t mle 259 in the mass spectrum. (+)-Epiisoelaeocarpiline is therefore isomeric with (-)-isoelaeocarpiline, and the spectral properties of the alkaloid, particularly the n.m.r. spectrum (Fig. l (a)) , indicate a close relationship

r I

Fig. 2.-(a) 0.r.d. spectra (methanol solutions) of: A, (+)-elaeocarpiline: B, (+)-epiisoelaeo- carpiline ; C, ( - )-eplelaeocarpiline ; D, ( - j-isoelaeocarpiline. ( 6 ) 0.r.d. spectra (methanol solutions) of: E, ( +)-dihydroelaeocarpiline ; F , ( + )-dihydroepiisoelaeocarpiline ; (2, ( - )-&hydro-

epielaeocarpiline; H, (-)-dihydroisoelaeocarpiline.

between the two alkaloids. The only obvious difference between the 100-MHz n.m.r. spectra is the chemical shift of the C 16 methyl doublets (6 0.99 for (4) and 6 0.85 for (1)). This chemical shift difference is consistent with a different relative configuration a t C 16. The close structural resemblance between (+)-epiisoclaeocarpiline and (-)-isoelaeocarpiline has been confirmed chemically by a study of the products formed by dehydrogenation over palladium-charcoal in benzene a t reflux temperature. (+)-Epiisoelaeocarpiline, like (-)-isoelaeocarpiline, affords a mixture of two products, and one of these products is (+)-isoelaeocarpine (5), the optical enantiomer of (-)-isoelaeocarpine (3). The properties of the other product, of molecular composition C16H23N02, indicate that i t is the 13,14-dihydro derivative of (+)-epiisoelaeocarpiline.

Cahn, R. S., Ingold, C. K., and Prelog, V., Experientia, 1956, 12, 8 1 .

ELAEOCARPUS ALKALOIDS. IV 1683

The formation of (+)-isoelaeocarpine (5) from (+)-epiisoelaeocarpiline (4), and of (-)-isoelaeocarpine (3) from (-)-isoeIaeocarpiIine (l), shows that the absolute configurations at the C7, C8, and C9 asymmetric centres are opposite in the two alkaloids. Moreover, as the spectroscopic and chemical evidence indicates that the only structural difference between the alkaloids is in the relative configuration at the C 16 centre, it follows that both alkaloids have the same absolute configuration at C16. (+)-Epiisoelaeocarpiline can therefore be assigned the 7S,8R,9R,16S con- figuration shown in (4). The stereochemical relationship between (+)-epiisoelaeo- carpiline and (-)-isoelaeocarpiline is supported by the 0.r.d. spectra (Fig. 2(a)) . In each spectrum there are two distinct Cotton effects, the signs of which are considered to depend upon the configuration at C 16 and C 8, the two asymmetric centres adjacent to the absorbing chromophores. A positive effect at 240 nm in each spectrum is assigned to the C 16 centre, while a negative effect at 350 nm in (-)-isoelaeocarpiline and a corresponding positive effect at 320 nm in (+)-epiisoelaeocarpiline are attributed to the C 8 configuration.

(c) ( + )-Elaeocarpiline (6)

A third isomer has been identified as (+)-elaeocarpiline (6), an alkaloid previously obtained from E. dolichostylis.3 The main structural features of this alkaloid were established3 from its spectroscopic properties and its conversion into (+)-elaeocarpine, but the relative configuration at C 16 could not be assigned. The 0.r.d. spectra of (+)-elaeocarpiline (Fig. 2(a)) (positive Cotton effects a t 240 and 320 nm) and of (+)-13,14-dihydroelaeocarpiline (Fig. 2 ( b ) ) are essentially the same as those of (+ )-epiisoelaeocarpiline (4) (Fig. 2(a)) and (+ )-13,14-dihydroepi- isoelaeocarpiline (Fig. 2 ( b ) ) respectively. I t can therefore be concluded that in these compounds the C 16 and C8 centres, which are those associated with the absorbing chromophores, have the same absolute configurations. As it was known from the earlier study3 that the configuration at the C 7 , C 8 , and C 9 centres of (+)-elaeo- carpiline (6) is C 7-H, C 8-H tmns-diaxial, C 8-H, C 9-H trans-diaxial, the absolute configuration of (6) can be represented as 7R.8R,9R,l6S. In accordance with this conclusion, the products previously obtained by heating (+ )-elaeocarpiline with palladium-charcoal in benzene3 are 7R,8R,9R-(+)-elaeocarpine (7), [aID t.206" and 7R,SR,9R,16S-(+)-13,14-dihydroelaeocarpiline, [KID +317".

( d ) ( - ) -Epielaeocarpililze (8)

A fourth isomer, (-)-epielaeocarpiline (8), m.p. 70-74", -396', has also been shown to have the molecular formula, ClsH21N02, by elementary analysis and by a molecular ion a t nzle 259 in the mass spectrum. There is a very close similarity between (-)-epielaeocarpiline and (+)-elaeocarpiline (6) in all spectroscopic pro- perties, and the only significant difference between the respective n.m.r. spectra is in the chemical shift of the C16 methyl doublet, a t 6 0.85 in the spectrum of ( - )-epielaeocarpiline and at 6 0.95 in the spectrum of ( +- )-elaeocarpiline. Dehydro- genation of (-)-epielaeocarpiline over palladium-charcoal in benzene gives a mixture of 78,88,98- ( - )-elaeocarpine (9), [a]D -210°, enantiorneric with (7), and the 13,14-dihydro derivative of (-)-epielaeocarpiline. From the na1.r. spectra

1684 S. R. JOHKS ET AL.

i t is clear that ( -)-epielaeocarpiline (Fig. 1 (b)) and ( + )-elaeocarpiline differ only in their relative stereochemistry a t C 16. The absolute configuration a t C 16 must there- fore be the same (168) in both alkaloids. The 0.r.d. curve of (-)-epielaeocarpiline (Fig. 2(a)) supports this assignment and shows a positive Cotton effect a t 240 nm typical of a 168 configuration and a negative effect a t 350 nm consistent with an 8 8 configuration. The absolute configuration of (-)-epielaeocarpiline can therefore be represented as 78,8S,9S,168.

(e) ( + )-Epialloelaeocarpiline (10)

As well as the four isomers ( l ) , (4), (6), and (8) which are present in all samples of E. sphaericus examined, there were a number of other components, detectable by thin-layer chromatography and by the n.m.r, spectra of chromatographic fractions, which appeared to vary markedly in their relative abundance in different batches of plant material. I n the light of present knowledge of the structures and stabilities of these compounds these differences may depend upon minor variations in the extrac- tion and isolation procedures. One of the compounds, (+)-epialloelaeocarpiline (lo), m.p. 136-137", [a]= +13g0, has been shown, by elementary analysis and by a molecular ion peak a t n ~ / e 259 in the mass spectrum, to have the molecular formula, C16H21N02, isomeric with the alkaloids already discussed. The presence of a dienone chromophore similar to that of the other isomers is indicated by the u.v, absorption (A,,, 325, 239, and 228 n n ~ ) and by signals from two double-bond protons in the n.m.r. spectrum (Fig. l(c)) a t 6 5.82 and 6.25. A three proton doublet a t 6 0.94 can be assigned to the C 16 methyl group as in the other isomers. Dehydrogenation of (+)-epialloelaeocarpiline over palladium-charcoal in benzene gives a complex mixture from which only 7S,8R,9R-(+)-isoelaeocarpine has been isolated in a pure state. The amount of pure (+)-isoelaeocarpine isolated by preparative thin-layer chromatography was too small for accurate determination of the optical rotation, but the sign of [a]= was determined by measuring the rotation of a small sample of the base recovered from the pure crystalline picrate.

ELAEOCARPUS ALKALOIDS. IV 1686

The assignment of a structure to (+)-epialloelaeocarpiline (10) depends primarily on the observation that when the alkaloid is allowed to remain adsorbed on thin-layer plates of Kieselgel G it is partly converted into 7S,8R,9R,16S-(+)-epi- isoelaeocarpiline (4). In the n.m.r. spectrum of (lo), the C7 proton resonates as a readily analysable octet at 6 4.22 from which the coupling constants J 7 , 8 14.0, J 6 , 7

5 - 5 , and J 6 , ~ 9.5 Hz can be assigned. The H7,H8 coupling constant is confirmed by the signal from the C8 proton which resonates as a quartet a t 6 2.96 ( J 7 , 8 14.0, JsB9 5 . 5 Hz). The large (3 14.0 Hz) coupling between C 7-H and C 8-H is consistent only with a trans-diaxial conformation for these protons and the 5 . 5 Hz coupling between C8-H and C9-H indicates an equatorial conformation for the C 9 proton. The apparently anomalous situation that (+)-epialloelaeocarpiline, which has C 7-H, C 8-H trans-diaxial, is converted into (4) with a cis B/C ring junction can be explained by the formulation of (+)-epialloelaeocarpiline as the C8 epimer of (+)-epiisoelaeocarpiline. Inspection of molecular models of the C8 epimer of (+)-epiisoelaeocarpiline indicates that a conformation in which ring c adopts a chair form with the indolizidine ring C/D cis is the only conformation consistent with the experimental data. Epimerization by enolization at C 8 has previously been discussed2 in relation to the aromatic bases (&)-elaeocarpine and (5)-isoelaeocarpine. In the interconversion of these bases, enolization at C8 is the first step in their equilibration, which involves breaking the C7-to-oxygen bond and subsequent ring closure at C7. On ring closure the two possible C 7 epimers (elaeocarpine and isoelaeocarpine) are formed in each instance but no evidence of epimerization at C8 was observed, and it was considered that a C/D cis junction of the type now favoured for (+)-epialloelaeocarpiline was less stable than a O/D trans junction. The earlier comments on the relative stabilities of these alternatives are in accordance with the ease of conversion of (? )-epiailoelaeocarfline i r , t ~ (+)-epiisae!aeooarpilin8 and the corresponding failure to observe any trace of (+)-epialloelaeocarpiline when (+)-epiisoelaeocarpiline is allowed to remain adsorbed on silica gel thin-layer plates for an extended time. Although indolizidines in general have a trans ring junction (nitrogen lone pair trans to C9-H), examples have previously been noted where there is evidence for a cis junction in the protonated form.237 On the basis of the structure assigned, the absolute configuration of (+)-epialloelaeocarpiline can be given as 7S,8X,9R,16S.

( f ) (-)-Alloelneocurpi2ine (11)

A sixth alkaloid, (-)-alloelaeocarpiline ( l l ) , has not been obtained entirely free from traces of other isomers. The n.m.r. spectrum is similar to that of (+)-epiallo- elaeocarpiline (10) except in the chemical shift of the C 16 methyl group (6 0.89).

7 Liining, B., and Lundin, C., Acta chem. scand., 1967, 21, 2136.

1686 S. It. JOHNS ET AL.

When allowed to remain adsorbed on silica gel thin-layer plates (-)-alloelaeocarpiline gave a mixture of the unchanged alkaloid and (-)-isoelaeocarpiline (I), [aID -400'. This easy conversion into (-)-isoelaeocarpiline can be explained by an epimerization a t C 8, analogous to that involved in the conversion of (+)-epialloelaeocarpiline (10) into (+)-epiisoelaeocarpiline (4). (-)-Alloelaeocarpiline (11) is therefore considered t o be the C8 epimer of (-)-isoelaeocarpiline with a C/D cis ring junction for the indolizidine ring system. The absolute configuration can accordingly be represented as 7R,8R,9S,16S.

( g ) (+)-Pseudoepiisoelaeocarpiline (12)

A seventh isomer, ( f )-pseudoepiisoelaeocarpiline, [a]= +222", has not been obtained crystalline, but its molecular formula has been shown to be Cl6Hzl~O2 by elementary analysis of a crystalline picrate, m.p. 230-235" (dec.), and by a molecular ion peak a t nzle 259 in the mass spectrum. The u.v. absorption of this isomer [Ama, 275 nm (E 7600) in ethanol] is different from those of the dienone isomers, and indicates the presence of an cr,,l3-unsaturated carbonyl system. The close relationship to the other isomers is established by catalytic hydrogenation to give 7S,8R,9R,16S- (+)-dihydroepiisoelaeocarpiline and by the n.m.r. spectrum (Fig. l(d)) which indicates the presence of a 14,15 rather than a 13,14 double bond. The n.m.r. spectrum (Fig. l(d)) shows a three-proton doublet a t 6 1.13 (J 6.5 Hz) which can be assigned to a C 16 methyl group, a narrow one-proton multiplet a t 6 4.55 (C7-H) which indicates a cis H 7,H 8 conformation, and two one-proton multiplets which are interpreted as a pair of AB doublets further split by couplings from vicinal protons such that the upfield multiplet is a pair of triplets and the more complex downfield multiplet a pair of unsymmetrical quintets. The chemical shift of H 16 can be given as 6 3.18 because it has been found that double resonance irradiation a t 6 3.18 collapses the C 16 methyl doublet to a singlet. The double-bond proton multiplets are also affected by irradiation a t the C16 proton signal, the upfield multiplet remaining essentially unchanged but the downfield multiplet collapsing to a pair of triplets. Irradiation a t 6 2.94 (the chemical shift of the C 13 methylene protons) collapses the 6 5.53 multiplet to a doublet and the 8 5.74 multiplet to a quartet. These double-resonance experiments allow the following analysis of the double- bond proton multiplets: 6 H 14 5.53, 6 H 15 5.'74; J 1 4 , ~ 5 10.0 HZ, J l 5 , ~ 6 3 . 5 Hz, Ji4 ,16 small; B(J14,13ax+J14,13eq) 3 .0 HZ, &(J15,13ax+J15,13ep) 2.0 HZ. They also confirm the position of the double bond a t C 14,C 15. The absolute configuration 7X,8R,9R,16X follows directly from the conversion of (+)-pseudoepiisoelaeocarpiline into (+)-dihydroepiisoelaeocarpiline.

(h) Other Constituents

The conzplexity of the mixture of alkaloids present in E. sphaericus, and the difficulty of separating mixtures of such closely similar stereoisomers, caused some uncertainty whether minor constituents obtained from some extracts were always present in E. sphaericus. The possibility that the different stereoisomers might in fact be an equilibrated mixture, either originally present in the plant or produced on work-up; would suggest that all the isomers could be obtained from all batches of

ELAEOCARPUS ALKALOIDS. IV 1687

E. sphaericus. In this case it would seem likely that all the stereoisomers may also be present in E. dolichostylis and E, altisectus.

The indole alkaloid, elaeocarpidine, was obtained from the extract of only one batch of E , sphaericus. Confirmation of the structure assigned to elaeocarpidine4 has been provided by two independent syntheses of this alkaloid.899 The trans,trans stereochemistry, originally assigned from conformational considerations to the two ring junctions involving nitrogen atoms,4 is also favoured by Gribble,g who has advanced supporting evidence for this conformation from a study of synthetic deutero-substituted derivatives of elaeocarpidine.

The aromatic bases, (f )-elaeocarpine and (-J-)-isoelaeocarpine, previously isolated from E. polydactylus,2 were also isolated in small amounts from all batches of E. sphaericus.

Another base, C16H24N202, has been obtained from E. sphaericus but insufficient material has been available for chemical study. The molecular com- position was confirmed by elementary analysis and by a molecular ion peak at m/e 276 in the mass spectrum. The i.r. spectrum shows a carbonyl band a t 1725 cm-1 which suggests a saturated carbonyl group, and the resemblance of the n.m.r. spectrum to those of the C16HzlN02 stereoisomers indicates the possibility that this new base has a similar ring system and is perhaps an artefact formed from one of the alkaloids by reaction with ammonia.

Apart from the isolation of elaeocarpidine and the alkaloid C16H24N202, a major proportion of the crude alkaloid fraction has not been included in the present study. This is the fraction not eluted from an alunlina column with benzene and which comprises the more polar alkaloids. This fraction is also a complex mixture of apparently similar, possibly isomeric, alkaloids which have at least one hydroxyl group. No detailed chemical studies has-e been carried out on these alkaloids.

REDUCTION OF SOME C16H21N02 STEREOISOMERS WITH SODIUM BOROHYDRIDE

In Part I13 it was shown that the reaction between (-)-isoelaeocarpiline (1) and sodium borohydride could be used to assign the relative configuration at C 16, whereas no conclusion regarding the (216 configuration could be reached from a study of the n.m.r. spectrunl of the reduction product from ( + )-elaeocarpiline. The present assignment of absolute configuration to all C16H21N02 stereoisomers allows an explanation of their borohydride reduction products. As previously shown,3 reduction of ( -)-isoelaeocarpiline affords ( -)-13,14-dihydroisoelaeocarpiline (13) in which the carbonyl group is hindered from attack by borohydride on the a-side by the C 16 methyl group, and on the P-side by the C9P and C l p hydrogens of ring D. As would be expected, attempts to further reduce (-)-13,14-dihydroisoelaeocarpiline (13) with sodium borohydride were unsuccessful.

In Part I13 sodium borohydride reduction of (+)-elaeocarpiline (6) was shown to afford a tetrahydro derivative which is now considered to be (14). Previously the relative configuration a t C16, C 11, and C 10 in (14) could not be assigned because

a Harley-Mason, J., and Taylor, C. G., Chem. Commun., 1969, 281. 9 Gribble, G. W., J. org. Chem., 1970, 35, 1944.

1688 S. R. JOHNS ET AL.

of the complexity of the n.m.r. spectrum. The known configuration a t the C16 centre in (+)-elaeocarpiline and the known steric requirements of sodium boro- hydride reagent would suggest steric hindrance to attack by sodium borohydride from the a-side of the molecule, with the result that the hydrogens a t C 11 and C 10 can be placed on the P-side. When (+)-13,14-dihydroelaeocarpiline (15) is reduced with sodium borohydride in ethanol only one C10 alcohol is obtained. Again the C l6a methyl would prevent attack by borohydride from the a-side of the carbonyl group, and a C lOcc hydroxyl configuration of the reduction product would be expected. A study of molecular models indicates that the dihedral angle between the C8 and C10 protons in the ClOa hydroxy derivative (16) is approximately zero, consistent with the measured coupling constant ( J 8 , l o 8 .0 Hz) for this product.

Similarly, when (-)-13,14-dihydroepielaeocarpiline (17) is reduced with sodium borohydride a single C 10 alcohol is formed. As before, the absolute con- figuration of (-)-13,14-dihydroepielaeocarpiline, in which the C 16 methyl group is a, requires a reduction product (18) in which the hydroxyl group assumes the hindered ( a ) configuration. The C8 and C 10 protons in (18) are trans to each other, and measurement from molecular models show that the dihedral angle is approximately 140". This dihedral angle is consistent with the measured coupling constant (JsVlo 8.0 Hz) for the alcohol (IS), but clearly the observed coupling constant could not be used for determining relative stereochemistry as the same coupling constant (J 8.0 Hz) was also consistent with a cis H 8,H 10 configuration in the alcohol (16) derived from (+ )-13,14-dihydroelaeocarpiline (15).

ELAEOCARPUS ALKALOIDS. IV 1689

As in the case of (+)-elaeocarpiline, the borohydride reduction of (-)- epielaeocarpiline (8) affords a tetrahydro derivative to which the analogous structure (19) has been assigned. The structure must be considered to be tentative as it is based on the known configuration of the starting product and the known steric requirements of sodium borohydride reduction. The n.m.r. spectrum cannot be used to confirm the assignments as i t is too complex for complete analysis.

(a) General

As in Part 1 . 2

Leaves of E. sphaericus (herbarium voucher specimen TGH 10006) were collected by Dr T. G. Hartley from a large tree (100 ft hlgh, 4 ft in diameter) growing by the Lae-Bulolo Road (long. 146" 47' E., lat. 6' 43' S.). Subsequent collections of E. sphaericus were made by Mr J. S. Womersley, and one collection of E. sphaericus (Hoogland No. 10147) was made at Ambunti on the Sepik River by Dr R. Hoogland.

(b ) Extraction of the Alkaloids

Dried leaves of E. sphaericus were milled and the crude alkaloids were extracted according to the method given in Part 1 . 2 In several large-scale extractions on amounts up to 35 kg, the yield of crude alkaloids ranged from 0.26 to 0.45 %.

(c) Separation of the Alkaloids

The separation of individual alkaloids from the complex mixture of crude alkaloids was a lengthy process, and a general outline of the methods, without a detailed description of each step, is set out below. Pure alkaloids were isolated only after repeated chromatography which afforded many mixed fractions and precise yields cannot be given. The effectiveness of the chromatographic separations was followed by t.l.c., n.m.r. spectroscopy, and in some instances by measuring the optical rotation of individual fractions. Observation of the doublet signals from the C 16 methyl substituents in the n.m.r. spectrum was usually the best method of following the separation of mixtures.

In a typical separation, the crude alkaloids (28 g) were dissolved in benzene and chromato- graphed on alumina (Woehlm neutral 300 g). Elution with benzene gave three fractions A (1.6 g), B ( 7 . 6 g), and C (200 mg), which were each collected in a volume of 600 ml. The remainder of the alkaloids, which was then stripped from the column by elution with chloroform and chloroform- methanol mixtures, has not been examined.

Fraction A was re-chromatographed on alumina (Spence type H), and 100-ml fractions were collected with light petroleum-benzene mixtures, followed by benzene, as the eluting solvents. The earlier fractions were rich in (-)-epielaeocarpiline (8) while the next fractions contained elaeocarpine and (+)-elaeocarpiline (6). Fractions rich in (+)-elaeocarpiline were followed by later fractions containing (+)-elaeocarpiline and the aromatic base isoelaeocarpine, and finally, by mixtures of (-)-isoelaeocarpiline (1) and (+)-epiisoelaeocarpiline (4).

Fraction (B) was partly crystalline and crystallization from acetone afforded some (-)-isoelaeocarpiline (1). The residues from the mother liquors were chromatographed in the same way as fraction (A), and the early fractions contained (+)-elaeocarpiline (6) and (-)-epielaeocarpiline (8). These were followed by a mixture of alkaloids, referred to as the pseudo-alkaloids, of which only (+)-pseudoepiisoelaeocarpiline (12) was isolated. Further elution gave mixtures rich in (+)-epiisoelaeocarpiline and containing (-)-isoelaeocarpiline, and these were followed by fractions consisting of pure (-)-isoelaeocarpiline.

Fraction C was a complex mixture and its properties indicated the presence of further alkaloids related to those from fractions A and B. Fractions corresponding to fraction C were obtained from several large scale separations of crude alkaloids, and those were combined and re-chromatographed to give fractions rich in (-)-alloelaeocarpiline (11) and (f )-epiallo- elaeocarpiline (10).

S. R. JOHNS ET AL.

(d) Characterization of the Alkaloids

(i) ( - )-Epielaeocarpiline (8)

Fractions rich in ( - )-epielaeocarpiline were re-chromatographed on Spence type H alumina and elution with light petroleum-benzene (8:2) gave (-)-epielaeocarpiline (160 mg), colourless crystals from hght petroleum, m.p. 72-74', [RID -396" (c, 0.06 in CHC13) (Found: C, 74.1 ; H, 8.2; N, 5.6. C I ~ H ~ I N O ~ requires C, 74.1; H, 8.2; X, 5.4%). A,,, (ethanol) 222, 240, 320 nm ( E 4500, 3700, 7200); vmax 1660 em-1; mass spectrum: mle 259 (&I+, 21%), 244 (21), 123 ( loo%, base peak), 122 (61), 95 (23), 91 (23), 83 (23), 82 (26), 69 (30), 55 (30); n.m.r. spectrum: 60.85(d,3H,J6.5Hz,C16-CH3),4.05(m, 1H,C7-H), 5.89(q, 1H,J13,14 9 . 5 H ~ , J 1 3 , ~ 5 3.5 HZ, C 13-H), 6.20 (m, lH, C 14-H).

Reduction of (-)-epielaeocarpiline in an atmosphere of hydrogen over platinum oxide in ethanol afforded (-)-dihyclroepielaeocarpiline, which was obtained by sublimation and crystal- lization from acetone as colourless needles, m.p. 124-126", [aID - 318" (c, 0.06 in CHC13) (Found : C, 73.2; H, 9.0; N, 5.6. C16Hs3NOa requires C, 73.5; H, 8.9; N, 5.4%). Amax 272 nm ( e 4820) in ethanol; vmax 1670 cm-1; mass spectrum: m/e 261 @I+, 15O/6), 246 (22), 168 (MI), 123 (100, base peak), 122 (61), 97 (39), 95 (33), 83 (56); 82 (45), 81 (33), 71 (45), 70 (33), 67 (33), 64 (56), 57 (78), 56 (22), 55 (89); n.m.r. spectrum: 6 1.01 (d, 3H, 5 6.5 Hz, C 16-CH3), 4.03 (m, IH, C 7-H).

Dehydrogenation of (-)-epielaeocarpiline over Pd/C in benzene, under the conditions described for the similar dehydrogenation of ( + ) -elaeocarpiline and ( - )-isoelaeocarpiline (Part II),3 gave a mixture of two products. The mixture treated w-ith concentrated hydrobromic acid gave a crystalline hydrobromide, which on crystallization from aqueous methanol gave (-)-elaeocarpine hydrobromide, m.p. 280-285'. The base, recovered from the crystalline hydro- bromide by basification with ammonia and extract'ion with chloroform, crystallized from acetone to give (-)-elaeocarpine, m.p. 104-10TO, [ a ] ~ -210" (c, 0.08 in CHC13). The i.r. and n.m.r. spectra u7ere identical with those of (+)-elaeocarpine' and (*)-elaeocarpine. The residue from treatment of the mixed products with hydrobromic acid wa,s basified, extracted w-ith chloroform, and the ext'racted material was chromatographed on preparative t.1.c. plates (Kieselgel G) which were developed in acetone-ethyl acetate (7 : 3). The product of higher RF, on crystallization from acetone, afforded (-)-elaeocarpine, m.p. 104-106". The lower RF component, on crystallization from acetone, gave (-)-dihydroepielaeocarpiline, m.p. 123-125', [aIn - 31 8" (CHCls), identical with ( - ) -dihydroepielaeocarpiline prepared above by hydro- genation of (-)-epielaeocarpiline.

(ii) ( +)-Elaeocarpiline (6)

Fractions rich in (+)-elaeocarpiline were re-chromatographed and recrystallized from acetone to constant melting point. ( f )-Elaeocarpiline, m.p. 165-166"; [orlo 4-395" (c, 0.08 in CHC13), showed no m.p. depression on mixing with (+)-elaeocarpiline previously isolated from E. dolichostylis, and the i.r. and n.m.r. spectra were identical.

(iii) ( i) -Elaeocarpine

The fractions eluted between the fractions rich in (-)-epielaeocarpiline and those rich in ( +)-elaeocarpiline contained mixtures of these two bases and ( 2)-elaeocarpine. Chromatography on alumina afforded fractions rich in (&)-elaeocarpine, to which concentrated aqueous HBr was added. The crystalline hydrobromide which separated was converted into the free base and crystallization from acetone gave near-racemic elaeocarpine, m.p. 81-82", c. 0.5" jc, 0.2 in CHC13), mixed m.p. with authentic ( =)-elaeocarpine, 81-82", and respective i.r. and n.m.r. spectra identical.

(iv) (&)-Isoelaeocarpine

Fractions containing ( +)-elaeocarpiline and (*)-isoelaeocarpine were re-chromatographed, and those fractions rich in (&)-isoelaeocarpine (estimated from n.m.r. spectra) were treated with ethanolic picric acid. The crystalline picrate which precipitated was filtered off and washed with ethanol. Recovery of t'he free base from the picrate gave near-racemic isoelaeocarpine, colourle~s

ELAEOCARPUS ALKALOIDS. IV 1691

crystals from acetone, m.p. 74-75', [&In c. $0.6 (c, 0.2 in CHCls), identical in its i.r. and n.m.r. spectra with (+)-isoelaeocarpine from E. polydactylus. The m.p, differed from that previously determined for (&)-isoelaeocarpinez (m.p. 51-62'), but the difference was evidently due to dimorphism, for a mixed m.p. determination with (f )-isoelaeocarpine, m.p. 51-52", gave m.p. 73-75', and ( &)-isoelaeocarpine, m.p. 51-62", gave m.p. 74-75" on recrystallization and seeding with the material of higher melting point.

(v) (+)-Pseudoepiisoelaeocarpili~ne (12)

Chromatography of the major fraction B gave mixtures of (+)-elaeocarpiline and (-)-epielaeocarpiline, and fractions which were designated the "pseudo-alkaloid" fractions. These fractions were re-chromatographed on alumina (Spence type H ) and a series of fractions were eluted with benzene-acetone (98 : 2). The first fractions were mixtures, but then a number of fractions were obtained, the n.m.r. spectra of which indicated a single component. Addition of ethanolic picric acid gave crystalline (+)-pseudoepiisoelaeoca~piline pictrate, m.p. 230-235" (Found: C,53.6; H,d.O; K, 11.2. C16H~lNO~,C~H3N30~requiresC,54.1; H,5.O; N, l l .5yO). The free base recovered from the picrate could not be induced to crystallize and it was obtained as a colourless gum, [aIn +22Z0 (c, 0.04 in CHC13); Xmax (ethanol) 276 nm ( E 7600); vmax

1665 cm-l; mass spectrum: mie 259 (M+, 85%), 258 (base peak, loo%), 244 (91), 172 (45), 171 (45), 130 (27), 124 (27), 123 (82), 122 (86), 97 (55), 84 (18), 83 (17), 82 (27), 77 (18), 70 (27), 69 (23), 57 (18), 56 (IS), 55 (18); n.m.r. spectrum: 6 1.13 (d, 3H, J 6.5 Hz, Cl&CH3), 4.55 (m, IH, C7-H), 5.53 (m, lH, C 14-H), 5.74 (m, IH, C15-H). Catalytic hydrogenation over PtOz in ethanol afforded ( + )-dihydroepiisoelaeocarpiline, [.*In + 145" (c, 0.07 in CHC13) ; n.m.r. spectrum: 6 1.06 (d, 3N, J 6.5 Hz, C 16-CH3) and 4 .42 (m, lH, C 7-H). The n.m.r. spectrum and i.r. spectrum were identical with the respective spectra of (+)-dihydroepi- isoelaeocarpiline obtained from (+)-epiisoelaeocarpiline (see (vii) below).

(vi) ( - )-Isoelaeocarpiline (I) The crystalline fractions obtained in the course of the chromatographic separation of the

alkaloids were recrystallized from acetone to give pure (-)-isoelaeocarpiline, m.p. 146-147", [&ID -400" (c, 0.08 in CHC13), mixed m.p. with (-)-isoelaeocarpiline from E. dolichostylis, 146-147". The i.r. and n.m.r. spectra of the two samples were identical.

Oxidation of (-)-18oelaeocarpili~ze (I).-(-)-Isoelaeocarpiline (500 mg) was dissolved in acetone (50 ml) and finely powdered KMn04 (500 mg) added. After 2 min, during which a brown sludge formed, the acetone was removed by evaporation, and 1 % aqueous NaOH solution (17 ml) was added to the residue. A saturated aqueous solution of KNn04 was then added with stirring until a permanent green colour was obtained. The solution was decolourized by addition of aqueous sodium sulphite solution and acidification with 2~ sulphuric acid. The aqueous solution was then exhaustively extracted with ether, and t,he ether solution dried over NaeS04 and evaporated to give a residue (40 mg). Analysis by g.1.c. [stationary phase Lac 2-R446 (Cambridge Industries Co. Inc.) 10.3% on Gas-chrom P (Applied Science Labs.) 80-100 mesh] indicated a complex mixture which contained one component having the same retention time as a reference sample of methylsuccinic acid (see below). Preparative g.l.c.(on this column) afforded a crystalline solid (4.1 mg), m.p. 90-102O, the i.r. spectrum of which indicated a mixture of acid and anhydride.

The mixture was dissolved in water (2 ml) and the solution, on evaporation to dryness over CaClz in a vacuum desiccator, gave 4-)-methylsuccinic acid, m.p. 102-105°, [ a ] ~ -12" (c, 0.06 in EzO) (lit. [a]= -15'), i.r. and mass spectra identical with those of authentic (&)-methyl- succinic acid. The n.m.r. spectrum of the ( -)-methylsuccinic acid in D20 solution shows peaks a t 6 1.38 (d, 3H, J 6.5 Hz, CH3), 360-420 Hz (m, 3H, CHgCH).

Alternatively, (-)-isoelaeocarplline (500 mg) was oxidized as above and the resulting mixture of acids (50 mg) methylated with diazomethane. The methyl esters were separated by preparative g.1.c. (liquid phase S.E. 30 on Chromosorb W support (80-100 mesh)), and the com- ponent corresponding in retention time to authentic dimethyl methylsuccinate was collected. The i.r., n.m.r., and mass spectra of the isolated ester were identical with those of authentic dimethyl methylsuccinate.

1692 S. R. JOHNS ET AL.

Authentic (j-)-methylsuccinic acid and dimethyl methylsuccinate were prepared for comparison. Itaconic acid was hydrogenated in aqueous solution over PtOz to give (+)-methyl- succinic acid, m.p. 100-105" after sublimation. The mass spectrum showed no molecular ion peak, that of highest rnle corresponding to the molecular weight of the anhydride (M+- 18). The mass spectrum showed peaks a t mle 144 (79% of base peak), 88 (16), 87 (26), 86 (95), 73 (92), 69 (34), 60 (24), 58 (la), 55 (45), 46 (74), 43 (42), 42 (100, base peak), 41 (74). methyla at ion with diazo- methane gave dimethyl methylsuccinate, a colourless hquid, mle 160 (M+ ZO/, of base peak), 129 (65), 128 (44), 101 (34), 100 (28), 89 (16), 69 (19), 59 (100, base peak), 41 (16).

(vii) (+)-Epiisoelaeocarpiline (4)

Fractions rich in (+)-epiisoelaeocarpiline, indicated by n.m.r, spectra and positive [ a ] ~ , were repeatedly re-chromatographed on alumina (Spence type H ; 500 g for each 1 g of alkaloid mixture). Elution with light petroleum-acetone (95 : 5) afforded ( $ )-epiisoelaeoca~piline (15 mg), colourless crystals from light petroleum, m.p. 98-101°, [aID $340" (c, 0.08 in CHC13) (Found: C, 74.0; H, 8.2; N, 5.4. C16H21N02 requires C, 74.1; H , 8.2; N, 5.4%). hmax (ethanol) 215 ( E 5000), 240 (4600), 320nm (7400); v,,, 1650 cm-1. Mass spectrum: mle 259 (Mt, l5%), 244 (20), 123 (100, base peak), 122 (55), 97 (30), 82 (20), 69 (30), 55 (26), 41 (45). N.m.r. spectrum: 6 0.99 (d, 3H, J 6.5 Hz, C 16-CH3), 4.56 (m, lH, C 7-H), 5.89 (q, lH, J 1 3 , 1 4

9 .5 Hz,J13,~5 3.5 HZ, C 13-H), 6.33 (m, lH, C 14-H). When (+)-epiisoelaeocarpiline (9 mg) was heated with palladium-charcoal in benzene, a

mixture of two products was obtained. The two compounds were separated by preparative t.1.c. on plates of Kieselgel G developed in ethyl acetate-acetone (7 : 3), and they were recovered from the Kieselgel G by elution with chloroform-methanol. One product, (+)-isoelaeocarpine, a colourless gum, picrate m.p. 245-24Io, approximate [ a ] ~ +98' (determined on a small sample recovered from the crystalline picrate), had i.r. and n.m.r, spectra identical with those of (-)-isoelaeocarpine obtained from (-)-isoelaeocarpiline. The other product, (+)-dihydroepi- isoelaeocarpiline, was obtained as a colourless gum (2.5 mg), [&ID + 140" (c, 0.05 in CHC13) and had i.r. and n.m.r. spectra identical with those of the dihydro derivative from pseudoepiiso- elaeo carpiline (Section (v)) ; see above.

(viii) ($)-Epial20elaeocarpiline (10)

Further chromatography indicated the presence of other compounds in fraction C but they were present in too low yield for isolation. From larger scale separations the fractions corresponding to fraction C were combined and the total material re-chromatographed on alumina (Spence type H). After repeated chromatography a series of fractions eluted by benzene- chloroform (9: 1) afforded crystals, which on recrystallization from acetone gave ( +)-epialloelaeo- carpiline, m.p. 136-137", [WID $139" (c, 0.11 in CHC13) (Found: C, 74.4; H, 8.4; N, 5.3; CleHzlNOz requires C, 74.1; H, 8.3; N, 5.496). Amax 228 ( E 5600), 239 (5400), 325 nm (8200); v,,, 1660 om-1, Mass spectrum: mle 259 (M+, 37% of base peak), 258 (17), 244 (34), 123 (100, base peak), 122 (65), 98 (31), 97 (21), 96 (31), 82 (21), 81 (28). N.m.r. spectrum: 6 0.94 (d, 3H, J 6.5 Hz, C 16-CH3), 2.96 (q, lH, J 8 , 7 14.0, J 8 , 9 5.5 Hz, C 8-H), 4.22 (octet, lH , 5 6 . 7 9.5 HZ, J e , 7

5 .5 Hz, C7-H), 5.82 (q, lH, 513 ,14 9 . 5 Hz, J13,15 3.0 HZ, C13-H), 6.25 (m, lH, C14-H). When heated with palladium-charcoal in benzene (+)-epialloelaeocarpiline gave a complex mixture which was shown to have a t least four components by t.1.c. examination. The component of highest RF (0.6) was isolated by preparative t.1.c. on plates of Kieselgel G developed in chloroform- methanol (9: I ) , and the i.r. and n.m.r. spectra of this compound were identical with those of isoelaeocarpine. With ethanolic picric acid, a crystalline picrate, m.p. 245-247", was obtained, and there was no melting point depression on mixing with a sample of the picrate of (+)-isoelaeo- carpine derived from ( +)-epiisoelaeocarpiline (see (vii) above). The free base was recovered from the picrate as a colourless gum, [aIn approximately $86" (c, 0.05 in CHC13).

Samples of (+)-epialloelaeocarpiline which had been shown to be pure by examination of their n.m.r, spectra were spotted on t.1.c. plates (Kieselgel G), and after allowing the material to remain adsorbed for 24 hr, the plates were developed in chloroform-methanol (9: 1). Two com- ponents were then detected, and from visual comparison of the intensity of the colour developed on exposure of the plates to iodine vapour, they were estimated to be present in a ratio of c. 9: 1.

ELAEOCARPUS ALKALOIDS. IV 1693

The components of the mixture resulting from prolonged contact with Kieselgel G were separated by preparative t.1.c. The major component was (+)-epialloelaeooarpiline, identical with the starting material. The minor product was identified as ( +)-epiisoelaeocarpiline, m.p. and mixed m.p. 98-10O0, [ a ] ~ +33g0 (c, 0.04 in CHC13). The i.r. and n.m.r. spectra were identical with those of (+)-epiisoelaeocarpiline.

(ix) ( - ) - Alloelaeocarpiline ( 1 1 )

After separation of the (+)-epialloelaeocarpiline fractions the remainder of the main fraction C was repeatedly chromatographed on alumina. One series of fractions eluted with benzene-chloroform (9: 1) gave crystalline material, which on recrystallization from acetone had m.p. 131-134'. Although only a single spot could be detected by t.l.c., the n.m.r. spectrum indicated that the crystalline material was an approximately 1 : 1 mixture of two components A ((-)-alloelaeocarpiline) and B (an uncharacterized compound which appeared to be closely related to (4)-pseudoepiisoelaeocarpiline). The signals in the n.m.r. spectrum of the mixture could be assigned as follows: 6 0.89 (d, 3H, J 6.5 Hz, C 16-CH3 of A), 1.05 (d, 3H, J 6.5 Hz, C 16-CH3 of B), 4.22 (broad multiplet, 2H, C7-H of A and B), 5.50 (m, lH, C14-H of B), 5.70 (m, lH, C15-H of B), 5.89 (q, lH,Jl3,149.5Hz,J13,15 3.OHz, C13-H ofA), 6.28 (m, 1H, C 14-H of A). Careful repetition of the chromatographic separation ultimately gave a fraction, estimated from its n.m.r. spectrum to be 90% pure (-)-alloelaeocarpiline, [eln approx. -73' (c, 0.03 in CHC13). As with ( + )-epialloelaeocarpiline, ( - )-alloelaeocarpiline isomerized when allowed to remain adsorbed on Kieselgel G t.1.c. plates, and was partly converted into ( -)-isoelaeo- carpiline. Separation by preparative t.1.c. after 3 days contact with Kieselgel G gave (-)-isoelaeo- carpiline, m.p. and mixed m.p. 146-145", [ a ] ~ -395" (c, 0.05 in CHC13) and (+)-epialloelaeo- carpiline containing c. 10% of the unknown contaminant B.

(x) Alkaloid C16H24hTz02 and Elaeocarpidine

Only a limited exammation was made of the constituents of the mixtures eluted from the column after the main fractions A, B. and C had been eluted by benzene. In the course of the fractionation of the alkaloids from one batch of E. sphaericus (Hoogland No. 10147 collected on the Sepik River), a series of fract~ons, eluted by benzene-chloroform (1 : 1) from an alumina column (Spence type H neutralized with ethyl acetate), were combined and re-chromatographed on Spence type H alumina. A series of fractions eluted by mixtures of benzene and chloroform (ranging In composition from 9 : 1 to 7 : 3) contained crystalline material, and recrystallization from acetone gave an alkaloid as colourless needles, m.p. 161-163', [aID -171' (c, 0.35 in CHC13), v,,, (CHC13) 1725 cm-1 (saturated oarbonyl), 3400 cn-1 (NH). There were no strong absorption bonds in the u.v. spectrum, and the probable presence of an NH group was confirmed by the formation of a product having a strong i.r. band a t 1635 cm-1 (amide) on reaction with acetic anhydride-pyridine at room temperature (Found: C, 69.4; H, 8.6; N, 10.1. C16H24N202 requires C, 69.5; H, 8.8; N, 10.1%). Nass spectrum: mle 276 (M+, 30% of base peak), 248 ( l l ) , 233 (26), 232 (base peak, loo), 215 (22), 207 (30), 190 (18), 122 (19), 97 (23). The n.m.r. spectrum showed a CH&H doublet a t 6 1.06 (J 6.5 Hz), and a broad signal a t 6 5.30 from a proton exchangeable with DzO was assigned to an S H group.

Following the elution of the alkaloid C16Hz4N202, the next series of fractions eluted by benzene-chloroform (1: 1) contained the inclole alkaloid elaeocarpidine, which was isolated by crystallization from ethanol as colourless crystals, m.p. 229-230". Elaeocarpidine was identified by its spectroscopic properties and by a mixed m.p. determination (mixed m.p. 229-230').

Similar fractionation of another batch of E. sphaericus alkaloids led to the isolation of the alkaloid C16H24N202, but elaeocarpidine was not obtained.

(e) Reductions with Sodium Borohydride

(i) (-)-Epielaeocarpiline (8)

Sodium borohydride in excess was added to a solution of (-)-epielaeocarpiline (8) in ethanol. The solution, after standing a t room temperature for 2 days, was diluted with water, acidified bjr addition of dilute H2S04, and finally made alkaline with ammonia. Extraction with

1694 S. R. JOHNS ET AL.

chloroform gave the crystalline tetrahydro derivative (191, which on crystallization from acetone and sublimation was obtained as colourless needles, m.p. 174-176", [aID -74" (c, 0.08 in CHC13) (Found: C, 73.4; H, 9.7; W, 5.3. ClsHzsNOz requires C, 73.0; H , 9 .6; S, 5.3%). vmax (CC14) 3640cm-l. Mass spectrum: mle 263 (M+, 71% of base peak), 245 (3), 122 ( lo) , 97 (L2), 84 (base peak, 100), 83 (28), 82 (20), 69 (12), 55 (281, 42 (161, 41 (24). N.m.r. spectrum: 6 1.02 (d, 3H, J 6.5 Hz, C 16-CHz), 5.38 (d, l H , J 2 . O Hz, C 14-H), 340-380 Hz (m, 2H, C 7-H, C 10-H).

(ii) (-)-13,14-Dihydroepielaeocarpiline (17)

Sodium borohydride reduction of ( - ) - 13,14-d~hydroepielaeocarpiline (1 7) afforded an alcohol (181, colourless crystals from acetone, m.p. 164-166", [elD - 133O (c, 0.04 in CHC13) (Found: C, 73.0; H , 9.6; N, 5.3. C16H25N02 requires C, 73 0; H , 9 .6; S, 5.3%). v,,, (CC14) 3650 cm-l. Mass spectrum: m/e 263 (M+, 206 of base peak), 245 (4%), 122 (22), 97 (14), 84 (base peak, 100), 83 (47), 82 (31), 69 (121, 55 (29), 42 (16), 41 (21). N.m.r. spectrum: 6 1.10 (d, 3H, J 6 .5 Hz, C 16-CHs), 3.46 (m, lH , C 7-H), 3.91 (d, l H , Js,lo 8 .0 Hz, C 10-H).

(iii) ( +)-I 3,14-Dihydroelaeocarpiline (15)

Sodium borohydride reduction of ( +)-13,14-dihydroelaeocarpiline (15) gave a n alcohol (161, colourless crystals from acetone, m.p. 191-193", [eln + 140" (c, 0.03 in CHC13) (Found: C, 73.3; H , 9 .8 ; N, 5.3. CleHzjhTOz requires C, 73.0; H. 9 .6 ; K, 5.3%). v,,, (CHC13) 3650 cm-1. Mass spectrum: mle 263 (&I+, 1% of base peak), 245 (4), 122 (151, 97 (151, 85 (base peak, 100), 83 (40), 82 (35), 69 (151, 55 (25), 42 ( I s ) , 41 (17). S.m.r. spectrum: 6 1 .03 (d, 3H, J 6 . 6 Hz, C16-CH3), 3.42 (m, l H , C7-H), 4.04 (d, lH , J S.OHz, C10-H).

( f ) Extraction of Alkaloids of E. altisectus

Leaves of Elaeocarpus altisectus Schltr. (herbarium voucher specimen TGH 10515) were collected from a tree (30 m high; 1 m diam.) growing in rain forest along the Lae-Bulolo Road (long. 146' 47' E., lat. 6" 43' 8.). Extraction of the milled dried leaves (5 kg) by the method used for the extraction of E. sphaericus leaves gave 32 g crude alkaloids. Examination by t.1.c. indicated a close resemblance to the alkaloids of E. sphaericus, and preliminary chemical studies supported this conclusion.

Chromatography on alumina gave fractions which, from t.1.c. and spectroscopic examina- tion, appeared to be essentially pure epielaeocarpiline, elaeocarpiline, and isoelaeocarpiline respectively. Only the isoelaeocarpiline fractions were selected for purification, and crystallization of these fractions from acetone gave (-)-isoelaeocarpiline, m.p. 146-147", [air, -396" (c, 0.04 in CHCls).

The authors are greatly indebted to Dr T. G. Hartley, Mr J. S. Womersley, and Dr R. Hoogland for the collection of leaves of E. sphaericus.