AN EFFICIENT AND GENERAL ENANTIOSELECTIVE SYNTHESIS OF SOME ISOXAZOLE-CONTAINING ANALOGS OF THE NEUROEXCITANT GLUTAMIC-ACID

Isoxazole amino acids are an important class of neuroexcitant which ar e difficult to prepare in enantiopure form. Diastereoselective alkylat ion of the enantiomerically pure glycine derivative, t-butyl)-3-methyl -4-oxo-1-imidazolidinecarboxylate (Boc-BMI) with omomethyl-2-methoxyme thyl-5-methylisoxazolin-5-one 5 or 5-bromomethyl-4-bromo-3-methoxyisox azole gives intermediates which under mild hydrolysis conditions produ ce the amino acids (S)- and (R)-bromohomoibotenic acid and (S)- and (R )-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid with e.e. >99%. (C) 1998 Elsevier Science Ltd. All rights reserved.