Lithium Hydroxide → 3-Oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carbaldehyde

HRID 1518009Notes

Reaction equation

HRID 1518009 reaction equation
[O:1]=[C:2]1[NH:7][C:6]2[CH:8]=[C:9]([C:12](O)=[O:13])[CH:10]=[CH:11][C:5]=2[S:4][CH2:3]1.COC(C1C=CC2SCC(=O)NC=2C=1)=O.[Li+].[OH-]>C1COCC1.O>[O:1]=[C:2]1[NH:7][C:6]2[CH:8]=[C:9]([CH:12]=[O:13])[CH:10]=[CH:11][C:5]=2[S:4][CH2:3]1

Participants

5

Reactant 3

HCID 3939Lithium HydroxideHCID 699501Methyl 3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylateHCID 7609933-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylic acid

Product 1

HCID 109433483-Oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carbaldehydeYield 60%

Reagents, catalysts & solvents 1

HCID 21881883Oxolane--water (1/1)Solvent

Procedure

3-Oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carboxylic acid. To a solution of 3-oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carboxylic acid methyl ester (1.5 g, 6.7 mmol) in a THF/H2O mixture (1:1, 63 mL) was added 4 N LiOH (8.0 mL, 32 mmol) and the resulting solution was stirred at RT for 24 h. The solution was partially concentrated and diluted with H2O (50 mL). The solution was acidified using concentrated HCl and a solid precipitated. The solid was collected via filtration, washed with H2O and dried in vacuo to provide 0.79 g (60%) of the title compound as a white solid. MS (ESI): exact mass calculated for C9H7NO3S, 209.01; m/z found, 210.2 [M+H]+. 1H NMR (500 MHz, CD3OD): 7.65-7.61 (m, 2H), 7.40 (d, J=8.1, 1H), 3.48 (s, 2H).

Workup

  1. concentrationThe solution was partially concentrated
  2. additiondiluted with H2O (50 mL)
  3. customa solid precipitated
  4. filtrationThe solid was collected via filtration
  5. washwashed with H2O
  6. customdried in vacuo

Sources & evidence

ORD record
ord-d8970806c77b42059eafaf2afad9e515
Source dataset
uspto-grants-2012_07
Patent number
US08232391B2

Reaction notes

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