Ammonia → 4-Carbamoylmethyl-2-(3,5-di-tert.-butyl-4-hydroxybenzylidene)-3,4-dihydro-3-oxo-2H-1,4-benzothiazine

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Reaction Conditions

Reaction Steps

0.1N hydrochloric acid in methanol (3 ml) was added to a solution of 2-(3,5-di-tert.-butyl-4-hydroxybenzylidene)-3,4-dihydro-4-ethoxycarbonylmethyl-3-oxo-2H-1,4-benzothiazine (Compound No. 1-1, 0.4 g) in 17.85 N ammonia in methanol (15 ml). After the addition, the mixture was stirred for 4 days at 80° C. in a sealed tube and followed by concentration in vacuo. To the residue, dilute hydrochloric acid was added and the whole was extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate and concentrated in vacuo. The oily residue was purified by silica gel column chromatography to give 0.14 g (37.3%) of the titled compound.

Provenance & Evidence