Hydrochloric Acid → ethyl (2E)-2H-1,4-benzothiazin-3(4H)-ylideneethanoate

Participants

Reaction Conditions

Reaction Steps

steps 1 and 2—To a solution of 6-nitrobenzothiazole (10, 10.2 g, 57 mmol) in EtOH (500 mL) was added KOH (7.0 g, 125 mmol). The reaction was heated at reflux for 15 min then cooled to 0° C. Ethyl chloroacetoacetate (9.3 g, 57 mmol) was added and the mixture stirred at RT for 1 h. The reaction mixture was poured into 1N HCl (500 mL) and the resulting solid was collected. The solid was dissolved in EtOAc. The organic phase was washed with brine, dried (MgSO4) and the solvent was removed under reduced pressure. The product was purified by SiO2 chromatography eluting with 10% EtOAc/hexane to afford 0.61 g (70%) of 12a: LCMS RT 3.48 min, M+H.

Provenance & Evidence