Nitric Acid → 2,3-dihydro-8-nitro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile 10-oxide

HRID 27749Notes

Reaction equation

HRID 27749 reaction equation
[O:1]=[C:2]1[NH:15][CH:14]=[C:5]2[S:6][C:7]3[CH:13]=[CH:12][CH:11]=[CH:10][C:8]=3[NH:9][C:4]2=[C:3]1[C:16]#[N:17].S(=O)(=O)(O)[OH:19].[N+:23]([O-])([OH:25])=[O:24]>O>[N+:23]([C:12]1[CH:11]=[CH:10][C:8]2[NH:9][C:4]3[C:5](=[CH:14][NH:15][C:2](=[O:1])[C:3]=3[C:16]#[N:17])[S:6](=[O:19])[C:7]=2[CH:13]=1)([O-:25])=[O:24]

Participants

5

Reactant 3

HCID 944Nitric AcidHCID 1118Sulfuric AcidHCID 125702342,3-dihydro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile

Product 1

HCID 233419942,3-dihydro-8-nitro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile 10-oxide

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a solution of 5 parts of 2,3-dihydro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile in 90 parts of concentrated sulfuric acid at 0° is slowly added, with stirring, 7 parts of concentrated nitric acid. The resultant mixture is stirred at room temperature for 1 hour, whereupon 2 volumes of water is slowly stirred in. The light yellow precipitate which forms is filtered out and recrystallized from aqueous N,N-dimethylformamide to give needles of 2,3-dihydro-8-nitro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile 10-oxide solvated 1:1 with N,N-dimethylformamide which melts above 310°. The solvent of crystallization can be removed by prolonged heating at around 200° in vacuo.

Workup

  1. stirringis slowly stirred in
  2. filtrationThe light yellow precipitate which forms is filtered out
  3. customrecrystallized from aqueous N,N-dimethylformamide

Sources & evidence

ORD record
ord-86d26cd06fd446f1b7dc2504949ce85e
Source dataset
uspto-grants-1980_09
Patent number
US04223136

Reaction notes

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