E. Juaristi, J. Escalante, B. Lamatsch
Apr 1, 1992
Citations
0
Influential Citations
62
Citations
Journal
Journal of Organic Chemistry
Abstract
An improved procedure for the preparation of (R)- and (S)-3-aminobutanoic acids (2a) through diastereomer separation of the corresponding (1'S)-N-phenethyl derivatives 1 is reported. From 2a, the four possible stereisomeric perhydropyrimidin-4-ones 4 were prepared through the amide 2c and the Schiff base 3. In the cyclisation of 3, the cis products 4 predominante ca, 95:5. These heterocycles can be alkylated (LDA, RX), as demonstrated by methylation and benzylation, with formation of a single diastereoisomer (5,6). Hydrolysis (6 N aqueous HCl) of these 5,6-dialkylperhydropyrimidin-4-ones leads to the free amino acids 7-10