6-(Hydroxymethyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one → 3-Oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]thiazine-6-carbaldehyde

Participants

Reaction Steps

A solution of 6-hydroxymethyl-3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]thiazine (330 mg, 1.68 mmole) in CH2Cl2 (30 mL) and THF (30 mL) was treated with MnO2 (730 mg, 8.40 mmole), and the mixture was stirred at RT. Additional MnO2 was added after 1 hr (730 mg, 8.40 mmole) and after 16 hr (300 mg, 3.45 mmole). After a total of 20 hr the mixture was filtered through kieselguhr and the filtrate was concentrated to dryness. The reside was triturated with 1:1 EtOAc/hexanes, collected, and dried to afford the title compound (180 mg, 55%) as a solid: MS (APCI−) m/e 195 (M−H)−.

Provenance & Evidence