Hydrochloric Acid → 6-(Hydroxymethyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one

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Reaction Steps

A solution of 3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]thiazine-6-carboxylic acid (500 mg, 2.38 mmole) and triethylamine (0.396 mL, 2.84 mmole) in THF (24 mL) was cooled to −10° C. and isobutyl chloroformate (0.339 mL, 2.61 mmole) was added. After 20 min the suspension was filtered through kieselguhr into an ice-cooled solution of sodium borohydride (272 mg, 7.19 mmole) in water (8 mL). The mixture was stirred for 30 min, then the pH was adjusted to 7 with dilute HCl. The solvent was evaporated and the residue was triturated with water. The solid was collected and dried under vacuum to give the title compound (346 mg, 74%) as a white solid: MS (APCI−) m/e 197 (M−H)−.

Provenance & Evidence