Reaction #1528440

Reaction equation

6-Hydroxymethyl-3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]thiazine

THF

→

solid

Yield 55.1%

3-Oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]thiazine-6-carboxaldehyde

Yield 55.1%

Solvents

dichloromethane

Conditions

Workup

1. 1
   FiltrationAfter a total of 20 hours the mixture was filtered through kieselguhr
2. 2
   Otherthe filtrate evaporated
3. 3
   OtherThe product was triturated with EtOAc/hexane (1:1)
4. 4
   Othercollected

Procedure

A solution of 6-Hydroxymethyl-3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]thiazine (330 mg) in dichloromethane (30 mL)/THF (30 mL) was treated with manganese dioxide (730 mg) and stirred at room temperature. Further manganese dioxide was added after 1 hour (730 mg) and 16 hours (300 mg). After a total of 20 hours the mixture was filtered through kieselguhr and the filtrate evaporated. The product was triturated with EtOAc/hexane (1:1) and collected to give a solid (180 mg); MS (APCI−) m/z 195 ([M−H]−, 95%), 165 (100%).

Source