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

HRID 885670Notes

Reaction equation

HRID 885670 reaction equation
[OH:1][CH2:2][C:3]1[CH:4]=[CH:5][C:6]2[S:11][CH2:10][C:9](=[O:12])[NH:8][C:7]=2[CH:13]=1>C1COCC1.C(Cl)(Cl)Cl.O=[Mn]=O>[O:12]=[C:9]1[NH:8][C:7]2[CH:13]=[C:3]([CH:2]=[O:1])[CH:4]=[CH:5][C:6]=2[S:11][CH2:10]1

Participants

4

Reactant 1

HCID 218737006-(Hydroxymethyl)-2H-benzo[b][1,4]thiazin-3(4H)-one

Product 1

HCID 109433483-Oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carbaldehydeYield 57.5%

Reagents, catalysts & solvents 2

HCID 14801Manganese dioxideCatalystHCID 21956068Chloroform tetrahydrofuranSolvent

Conditions

Temperature
70 °C

Procedure

To a solution of 6-hydroxymethyl-4H-benzo[1,4]thiazin-3-one (360 mg, 1.8 mmol) in THF/CHCl3 (2:1, 18 mL) was added MnO2 (1.6 g, 18 mmol) and the resulting suspension was heated to 70° C. and stirred for 4 h. The suspension was filtered through diatomaceous earth and the filtrate was concentrated. The resulting solid was triturated with EtOAc/hexanes (1:1) and a minimal amount of CH3OH to provide 200 mg (56%) of the title compound as a tan solid. MS (ESI): exact mass calculated for C9H7NO2S, 193.02; m/z found, 194.1 [M+H]+. 1H NMR (500 MHz, CDCl3): 9.94 (s, 1H), 8.78 (br s, 1H), 7.54-7.49 (m, 2H), 7.37 (d, J=1.5, 1H), 3.52 (s, 2H).

Workup

  1. filtrationThe suspension was filtered through diatomaceous earth
  2. concentrationthe filtrate was concentrated
  3. customThe resulting solid was triturated with EtOAc/hexanes (1:1)

Sources & evidence

ORD record
ord-5d82461db8b34ae2b2f094a93fd85335
Source dataset
uspto-grants-2012_08
Patent number
US08242275B2

Reaction notes

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