Preparation of glutaric acid derivatives

Abstract From the Canadian patent

The invention provides a process for preparing a compound of the formula:, (see fig.I), (wherein R2 is hydrogen or C1-C6 alkyl optionally substituted by up to 3 substituents each independently selected from C1-C6 alkoxy and C1-C6 alkoxy(C1-C6 alkoxy)-; and R3 is C1-C6 alkyl or benzyl, said benzyl group being optionally ring-substituted by up to 2 nitro or C1-C4 alkoxy substituents), or a base salt thereof comprising reaction of a compound of the formula: (see fig.II), (wherein R is C1-C4 alkyl phenyl, benzyl or C1-C4, alkoxy;, and R2 and R3 are as defined above) with hydrogen peroxide or a source of peroxide ions, optionally followed by conversion of the compound of the formula (I) to a …