Hydrochloric Acid → 8-amino-2,3-dihydro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile

HRID 27751Notes

Reaction equation

HRID 27751 reaction equation
[N+:1]([C:4]1[CH:20]=[CH:19][C:7]2[NH:8][C:9]3[C:10](=[CH:12][NH:13][C:14](=[O:18])[C:15]=3[C:16]#[N:17])[S:11][C:6]=2[CH:5]=1)([O-])=O.Cl>C(O)(=O)C>[NH2:1][C:4]1[CH:20]=[CH:19][C:7]2[NH:8][C:9]3[C:10](=[CH:12][NH:13][C:14](=[O:18])[C:15]=3[C:16]#[N:17])[S:11][C:6]=2[CH:5]=1

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 23341995HCID 23341995, compound

Product 1

HCID 233419928-amino-2,3-dihydro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To a suspension of 25 parts of a 1:1 solvate of 2,3-dihydro-8-nitro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile in 1000 parts of glacial acetic acid is added a solution of 75 parts of stannous chloride dihydrate in 230 parts of 28% hydrochloric acid. The resultant mixture is heated at the boiling point under reflux with stirring for 2 hours, then chilled. Insoluble solids are filtered out and dissolved in a mixture of 1100 parts of sulfinylbis[methane] with 200 parts of water. This solution is basified with concentrated ammonium hydroxide and thereupon diluted with 1 volume of water. The precipitate which forms is filtered off and consecutively recrystallized from (1) a mixture of sulfinylbis[methane] and methanol and (2) a mixture of sulfinylbis[methane], N,N-dimethylformamide, and water to give 8-amino-2,3-dihydro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile melting above 305°.

Workup

  1. temperatureunder reflux
  2. temperaturechilled
  3. filtrationInsoluble solids are filtered out
  4. dissolutiondissolved in a mixture of 1100 parts of sulfinylbis[methane] with 200 parts of water
  5. additiondiluted with 1 volume of water
  6. filtrationThe precipitate which forms is filtered off
  7. customconsecutively recrystallized from (1)
  8. additiona mixture of sulfinylbis[methane] and methanol and (2)
  9. additiona mixture of sulfinylbis[methane], N,N-dimethylformamide, and water

Sources & evidence

ORD record
ord-b2a431d7e1ef43edb72fb64eda8b0397
Source dataset
uspto-grants-1980_09
Patent number
US04223136

Reaction notes

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