p-Toluenesulfonic acid → Meloxicam

HRID 224607Notes

Reaction equation

HRID 224607 reaction equation
[OH:1][C:2]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[S:5](=[O:13])(=[O:12])[N:4]([CH3:14])[C:3]=1[C:15]([NH:17][C:18]1C=CC=CC=1)=[O:16].NC1[S:26][C:27]([CH3:30])=[CH:28][N:29]=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C(C)=CC=CC=1>[OH:1][C:2]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[S:5](=[O:12])(=[O:13])[N:4]([CH3:14])[C:3]=1[C:15]([NH:17][C:18]1[S:26][C:27]([CH3:30])=[CH:28][N:29]=1)=[O:16]

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 3517702-Amino-5-methylthiazoleHCID 546847802H-1,2-Benzothiazine-3-carboxamide, 4-hydroxy-2-methyl-N-phenyl-, 1,1-dioxide

Product 1

HCID 54677470MeloxicamYield 24%

Reagents, catalysts & solvents 1

HCID 7237O-XyleneSolvent

Procedure

1.0 gm (3 millimols) of 4-hydroxy-2-methyl-N-phenyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide were refluxed with 1.15 gm (10 millimols) of 2-amino-5-methyl-thiazole and 0.1 gm of p-toluenesulfonic acid in 250 ml of xylene for 72 hours. After cooling, the reaction mixture was washed with 2N hydrochloric acid and with water, dried and evaporated in vacuo. The residue was purified column-chromatographically (Merck-silica gel 60; particle size: 0.2-0.5 mm; eluant: chloroform/ethanol, 95:5), yielding 0.25 gm (24% of theory) of 4-hydroxy-2-methyl-N-(5-methy-2-thiazolyl)-2H-1,2-benzothiazine-3-caboxamide-1,1-dioxide.

Workup

  1. temperatureAfter cooling
  2. washthe reaction mixture was washed with 2N hydrochloric acid and with water
  3. customdried
  4. customevaporated in vacuo
  5. customThe residue was purified column-chromatographically (Merck-silica gel 60; particle size: 0.2-0.5 mm; eluant: chloroform/ethanol, 95:5)

Sources & evidence

ORD record
ord-f432adac9e5044f6adb1fdcf037a7279
Source dataset
uspto-grants-1980_11
Patent number
US04233299

Reaction notes

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