3-Methylglutaric acid → 8-chloro-3-methyl-2,3,4,4a-tetrahydro-10H-1,2-oxazino(3,2-b) (1,3)benzoxazin-10-one

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Reaction Steps

80 g. of the methyl half ester of 3-methylglutaric acid (Linstead, lunt and Weedon, J. Chem. Soc. 1950, 3331) was converted to methyl 4-bromo-3-methylbutyrate as described by Marks and Polgar, J. Chem. Soc. 1955, 3854. The bromoester (51 g.) was reduced with sodium bis (2-methoxyethoxy)aluminum hydride in a mixture of toluene and ether yielding 43 g. of 4-bromo-3-methylbutyraldehyde. The aldehyde and 49 g. of 5-chlorosalicylhydroxamic acid were condensed by the method described in Example 1 and the product was ring-closed with 10 percent aqueous sodium hydroxide to give 8-chloro-3-methyl-2,3,4,4a-tetrahydro-10H-1,2-oxazino(3,2-b) (1,3)benzoxazin-10-one which melted at 121- 140° C. after recrystallization from ethanol.

Provenance & Evidence