2001 ring closure reactions

ring closure reactionsO 0130

33 - 053Synthesis of β-Lactams and cyclo-β-Dipeptides from β-AminoAcids: Experimental Observations and Theoretical Analysis. —Phenylphosphonic dichloride activates 3-phenyl-3-aminopropanoic acids (I)and 2-benzyl-3-aminopropanoic acid (V) towards β-lactamization, whereas2,3-unsubstituted or 3-methyl-3-aminopropanoic acids (III) undergo in thepresence of PhPOCl2 cyclodipeptide formation. The yields depend on thesolvent, the temperature, and the amino acid concentration (optimum condi-tion: 0.01 M amino acid in benzene at reflux temperature). The experimentalresults are supported by theoretical calculations. — (ESCALANTE, JAIME;GONZALEZ-TOTOTZIN, MIGUEL A.; AVINA, JUDIT; MUNOZ-MUNIZ,OMAR; JUARISTI, EUSEBIO; Tetrahedron 57 (2001) 10, 1883-1890; Cent.Invest. Quim., Univ. Auton. Estado Morelos, 62210 Cuernavaca, Mex.; EN)

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