Stereochemical course of acylation and aldol condensation in (4S)-4-methyl-2-benzyl-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-diones
摘要:
Acylation of 1 leads to the syn derivatives 2. Traces of the anti isomers equilibrate to the syn isomers when stored in CHCl3. Aldol condensation showed great diastereoselectivity, but racemization could not be avoided. The configuration of the new introduced stereogenic centres has been assigned on the basis of H-1-NMR data and NOE measurements. (C) 1998 Elsevier Science Ltd. All rights reserved.