Sodium Hydroxide → 2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-2-carboxylic acid

HRID 399718Notes

Reaction equation

HRID 399718 reaction equation
C([O:3][C:4]([C:6]1([CH3:17])[C:11](=[O:12])[NH:10][C:9]2[CH:13]=[CH:14][CH:15]=[CH:16][C:8]=2[S:7]1)=[O:5])C.[OH-].[Na+]>O1CCOCC1>[CH3:17][C:6]1([C:4]([OH:5])=[O:3])[C:11](=[O:12])[NH:10][C:9]2[CH:13]=[CH:14][CH:15]=[CH:16][C:8]=2[S:7]1

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 10634501HCID 10634501, compound

Product 1

HCID 105370512-methyl-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-2-carboxylic acidYield 104.8%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

Ethyl-2-methyl-3,4-dihydro-3-oxo-2H-1,4-benzothiazine-2-carboxylate (0.251 g, 1 mmole) and 1N NaOH (2.2 ml, 2.2 mmoles) were stirred in dioxan (5 ml) for 48 hours at room temperature. The solvent was evaporated, water (5 ml) was added to the residue and it was acidified with 20% HCl to pH=2. The crystals which separated were filtered off by suction and recrystallized from absolute ethanol. Thus there were obtained 0.234 g (98.0%) of the title product in the form of white crystals, m.p. 164-°165° C.

Workup

  1. customThe solvent was evaporated
  2. additionwater (5 ml) was added to the residue and it
  3. customThe crystals which separated
  4. filtrationwere filtered off by suction
  5. customrecrystallized from absolute ethanol

Sources & evidence

ORD record
ord-2b95a46dde784de5a99e271db5a522bb
Source dataset
uspto-grants-1998_10
Patent number
US05824652

Reaction notes

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