Acetic Acid → Benzothiazole

Participants

Reaction Steps

Zinc powder (6.93 g, 106 mmol) was added to a stirred mixture of 4-(2-benzothiazinylsulfonyl)-3-(N,N-di-t-butoxycarbonylamino)-1-ethyloxycarbonylmethyl-2-pyridinone (3.94 g, 6.48 mmol) and acetic acid (8.73 mL) in ethanol (63 mL). After 16 h, the reaction mixture was filtered and evaporated in vacuo at rt. NCS (0.952 g, 7.13 mmol) was added to a stirred mixture of this residue in methylene chloride (100 mL) at -5° C. After 15 min the reaction was warmed to rt and after a further 40 min the reaction was filtered through celite and evaporated in vacuo to give the title compound contaminated with benzothiazole (1 equivalent) as a yellow solid;

Provenance & Evidence