438 Fresenius Z. Anal. Chem., Band 301 In diesem Zusammenhang verweisen wir auf unsere Ana- lysenvorschrift, dab nach Zugabe der Carminsfiure auf 50 ml aufzuffillen sei. Wit empfehlen dieses Verfahren wegen der schwierigen Handhabung der konz. Schwefels/iure. Wtirde man nicht auf 50 ml aufffillen, so wfirde ein Anreicherungs- faktor von 2 erreicht. Eine weitere M6glichkeit, den Borge- halt des Pyrolysats zu erhthen, besteht in der Verwendung grtBerer Tiegel. Dadurch ktnnen Probenmengen bis zu 10 g ohne Schwierigkeiten pyrolysiert werden. Dies ist deshalb nicht geschehen, weil die sehr griindlich untersuchten USGS- Referenzproben kaum mehr erhfiltlich sind. Literatur 1. Fleet, M. E. : Anal. Chem. 39, 253-255 (1967) 2. Hatcher, J. T., Wilcox, L. V. : Anal. Chem. 22, 567-569 (1950) 3. Kazarinova-Oknina, V. A. : Zavodsk. Laborat. 14, 263- 265 (1948) 4. Koch, O. G., Koch-Dedic, G. A. : Handbuch der Spuren- analyse. Berlin: Springer 1974 Eingegangen am 29. November 1979 Fresenius Z. Anal. Chem. 301,438 (1980) - by Springer-Verlag 1980 Identification of Some Closely Related Potential Antineoplastic Arylazopyrimidines by T.L.C. any of the compounds and the Roe-valuesobtained were found reproducible in the different identical runs. It has been observed that electron-donating groups reduce the rate of flow (Roe) of the spots in most of the cases whereas electron- withdrawing group increase it in comparison with that of the parent unsubstituted compound. Rajeev Jain*, D. D. Agarwal, and R. N. Goyal Department of Chemistry, University of Roorkee, Roorkee, India Identifizierung einiger eng verwandter potentieller antineoplastischer Arylazopyrimidine durch DC Key words: Nachw. von Arylazopyrimidinen; Chromatogra- phic, DiJnnschicht In view of the immense importance of arylazopyrimidines as potential antineoplastics it was considered worthwhile to study the separation of these compounds by T.L.C. The general structure of the 5-arylazo-2-thio-4-hydroxypyrim- idines is on _/R R,s.~N U where, R represents the different substituents, R' = H, CH 3 or C2H5. .Experimental. Glass plates of the size 21.5 • 21.5 cm z were coated with silica gel G (thickness 0.40 mm) with the help of Stahl type applicator and were developed in glass troughs. All the compounds were synthesized by the method developed in this laboratory and repeatedly recrystallized with ethanol before subjecting them to the separation. A 0.2 ~o methanolic solution of the compounds was applied to the plates with the help of fine glass capillaries. Solvent systems A and B were found to give a good separation of all the pyrimidines studied as shown by the Roe- values in Table 1. About 30min were required for the development. After development the colour of the spots was light yellow or light brown which was being darkened by exposure to NO 2 for about 1 min. No tailing was observed in Table 1 No. R R' Roe x 100 Detec- lion A B limit (Pg) I H H 62 70 1.5 II 2-C1 H 54 58 2.2 III 2-CH 3 H 41 36 1.5 IV 2-OCH 3 H 37 45 2.0 V 2-NO2 H 71 85 2.5 VI 4-C1 H 52 49 1.5 VII 4-CH 3 H 27 31 1.5 VIII 4-OCH 3 H 45 54 2.0 IX 4-OC2H5 H 59 45 1.0 X 4-NO2 H 75 91 2.0 XI H CH 3 58 73 2.5 XII 2-Br CH 3 45 69 1.0 XIII 2-OCH 3 CH 3 20 32 2.5 XIV 2-CH 3 CH 3 24 55 2.0 XV 4-Br CH 3 49 19 2.0 XVI 4-OCH 3 CH~ 29 34 2.5 XVII H CzH ~ 63 78 1.5 XVIII 2-Br Call 5 17 26 1.5 XIX 2-OCH a C2H 5 42 39 2.0 XX 2-NO 2 Call5 69 84 1.0 XXI 4-NO2 C2H ~ 82 89 2.0 XXII 4-Br C2H~ 39 29 2.5 XXIII 4-OCH 3 C2H ~ 34 23 2.5 XXIV 4-CH3 C2H s 30 45 2.0 Solvent composition: For compounds I-X (A) = CHC13 : CtH 6 (80 : 20); (B) = CHC13 : CH3COOCaH 5 : C6H 6 (60: 20: 20). For compounds XI-XXIV (A) = C6H6 : CH3OH (60:40); (B) = C6H 6 : CH3OH : C2HsCOCH 3 (50 : 40 : 10) * Address for correspondence: 224, Khandaq Street, Meerut-250002, India Received August 13, 1979; revised October 23, 1979

Identification of some closely related potential antineoplastic arylazopyrimidines by T.L.C

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Page 1: Identification of some closely related potential antineoplastic arylazopyrimidines by T.L.C

438 Fresenius Z. Anal. Chem., Band 301

In diesem Zusammenhang verweisen wir auf unsere Ana- lysenvorschrift, dab nach Zugabe der Carminsfiure auf 50 ml aufzuffillen sei. Wit empfehlen dieses Verfahren wegen der schwierigen Handhabung der konz. Schwefels/iure. Wtirde man nicht auf 50 ml aufffillen, so wfirde ein Anreicherungs- faktor von 2 erreicht. Eine weitere M6glichkeit, den Borge- halt des Pyrolysats zu erhthen, besteht in der Verwendung grtBerer Tiegel. Dadurch k tnnen Probenmengen bis zu 10 g ohne Schwierigkeiten pyrolysiert werden. Dies ist deshalb nicht geschehen, weil die sehr griindlich untersuchten USGS- Referenzproben kaum mehr erhfiltlich sind.

Literatur

1. Fleet, M. E. : Anal. Chem. 39, 253-255 (1967) 2. Hatcher, J. T., Wilcox, L. V. : Anal. Chem. 22, 567-569

(1950) 3. Kazarinova-Oknina, V. A. : Zavodsk. Laborat. 14, 2 6 3 -

265 (1948) 4. Koch, O. G., Koch-Dedic, G. A. : Handbuch der Spuren-

analyse. Berlin: Springer 1974

Eingegangen am 29. November 1979

Fresenius Z. Anal. Chem. 301,438 (1980) - �9 by Springer-Verlag 1980

Identification of Some Closely Related Potential Antineoplastic Arylazopyrimidines by T.L.C.

any of the compounds and the Roe-values obtained were found reproducible in the different identical runs. It has been observed that electron-donating groups reduce the rate of flow (Roe) of the spots in most of the cases whereas electron- withdrawing group increase it in comparison with that of the parent unsubstituted compound.

Rajeev Jain*, D. D. Agarwal, and R. N. Goyal

Department of Chemistry, University of Roorkee, Roorkee, India

Identifizierung einiger eng verwandter potentieller antineoplastischer Arylazopyrimidine durch DC

Key words: Nachw. von Arylazopyrimidinen; Chromatogra- phic, DiJnnschicht

In view of the immense importance of arylazopyrimidines as potential antineoplastics it was considered worthwhile to study the separation of these compounds by T.L.C. The general structure of the 5-arylazo-2-thio-4-hydroxypyrim- idines is

on _ / R

R,s.~N U

where, R represents the different substituents, R' = H, CH 3 or C2H5.

.Experimental. Glass plates of the size 21.5 • 21.5 cm z were coated with silica gel G (thickness 0.40 mm) with the help of Stahl type applicator and were developed in glass troughs. All the compounds were synthesized by the method developed in this laboratory and repeatedly recrystallized with ethanol before subjecting them to the separation. A 0.2 ~o methanolic solution of the compounds was applied to the plates with the help of fine glass capillaries.

Solvent systems A and B were found to give a good separation of all the pyrimidines studied as shown by the Roe- values in Table 1. About 30min were required for the development. After development the colour of the spots was light yellow or light brown which was being darkened by exposure to NO 2 for about 1 min. No tailing was observed in

Table 1

No. R R' Roe x 100 Detec- l ion

A B limit (Pg)

I H H 62 70 1.5 II 2-C1 H 54 58 2.2 III 2-CH 3 H 41 36 1.5 IV 2-OCH 3 H 37 45 2.0 V 2-NO2 H 71 85 2.5 VI 4-C1 H 52 49 1.5 VII 4-CH 3 H 27 31 1.5 VIII 4-OCH 3 H 45 54 2.0 IX 4-OC2H5 H 59 45 1.0 X 4-NO2 H 75 91 2.0 XI H CH 3 58 73 2.5 XII 2-Br CH 3 45 69 1.0 XIII 2-OCH 3 CH 3 20 32 2.5 XIV 2-CH 3 CH 3 24 55 2.0 XV 4-Br CH 3 49 19 2.0 XVI 4-OCH 3 CH~ 29 34 2.5 XVII H CzH ~ 63 78 1.5 XVIII 2-Br Call 5 17 26 1.5 XIX 2-OCH a C2H 5 42 39 2.0 XX 2-NO 2 Call5 69 84 1.0 XXI 4-NO2 C2H ~ 82 89 2.0 XXII 4-Br C2H~ 39 29 2.5 XXIII 4-OCH 3 C2H ~ 34 23 2.5 XXIV 4-CH3 C2H s 30 45 2.0

Solvent composition: For compounds I - X (A) = CHC13 : CtH 6 (80 : 20); (B) = CHC13 : CH3COOCaH 5 : C 6 H 6 (60: 20: 20). For compounds X I - X X I V (A) = C6H6 : CH3OH (60:40); (B) = C6H 6 : CH3OH : C2HsCOCH 3 (50 : 40 : 10)

* Address for correspondence: 224, Khandaq Street, Meerut-250002, India Received August 13, 1979; revised October 23, 1979