Potential GABA_B Receptor Antagonists. III. Folded Baclofen Analogs Based on Phthalide

Abstract

Possible analogues of baclofen, 3-aminomethyl-5-chloro-, 3-aminomethyl-6-chloro- and 3-aminomethyl-5,6-dichloro-isobenzofuran-1(3H)-one, have been prepared for evaluation as antispasticity agents. The corresponding 3-hydroxyisobenzofuran-l(3H)-one was reacted with ethyl acetoacetate under acidic conditions, and the keto ester hydrolysed and decarboxylated to give the 3-(2-oxopropyl)isobenzofuran-l(3H)-one; this was treated with hydrazoic acid, and the product was hydrolysed. A parallel series of (3-oxo-1,3-dihydroisobenzofuran-1-y1)glycines was obtained by treating the keto ester first with hydrazoic acid, and hydrolysis of the resulting acetamides.