2-Aminopyridine → Piroxicam

HRID 2291649Notes

Reaction equation

HRID 2291649 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]([O:17]C(C)C)=O.[NH2:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][N:23]=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:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][N:23]=1)=[O:17]

Participants

4

Reactant 2

HCID 104392-AminopyridineHCID 54686201Isopropyl-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate-1,1-dioxide

Product 1

HCID 54676228Piroxicam

Reagents, catalysts & solvents 1

HCID 7237O-XyleneSolvent

Procedure

A mixture of 74.3 g (0.25 mol) of isopropyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide and 25.7 g (0.32 mol) of 2-aminopyridine in 2,700 ml of xylene is maintained under reflux for 20 hours. During this time, approximately one third of the solvent is distilled off and is replaced, and finally the mixture is distilled to a final volume of 1,500 ml. The mixture is cooled to 0°-5° C. and filtered and the product washed with xylene. By crystallization with dichloroethane, 63 g (75%) of a crystalline white product, m.p. 198°-200° C. are obtained.

Workup

  1. temperatureis maintained
  2. temperatureunder reflux for 20 hours
  3. distillationDuring this time, approximately one third of the solvent is distilled off
  4. distillationfinally the mixture is distilled to a final volume of 1,500 ml
  5. temperatureThe mixture is cooled to 0°-5° C.
  6. filtrationfiltered
  7. washthe product washed with xylene
  8. customBy crystallization with dichloroethane, 63 g (75%) of a crystalline white product, m.p. 198°-200° C.
  9. customare obtained

Sources & evidence

ORD record
ord-8c6f48bfe6014e66817df79623f1bf3e
Source dataset
uspto-grants-1989_01
Patent number
US04797483

Reaction notes

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