Glyoxylic acid, monohydrate → Hwa 131

Participants

Reaction Conditions

Reaction Steps

4.8 g (0.05 mol) of glyoxylic acid monohydrate in 75 ml of water were added dropwise to a solution of 10.0 g (0.025 mol) of 2-amino-5-(3,5-di-tert.butyl-4-hydroxyphenyl)-6H-1,3,4-thiadiazine hydrobromide from step (c1) in 250 ml of glacial acetic acid and 25 ml of 4N hydrochloric acid at 80° C. After the mixture had been stirred at 80° C. for 20 hours, it was evaporated under reduced pressure. It was advantageously possible to purify the solid residue by column chromatography on silica gel using methylene chloride/methanol (25:1) as the eluent and subsequent recrystallization from ethanol, and, from analytical and spectroscopic investigations, the product proved to be identical to that prepared by procedures (a) and (b).

Provenance & Evidence