Hydrochloric Acid → 3,4-dihydro-2-methyl-3-oxo-2H-1,2-benzothiazine-4-carboxylic acid 1,1-dioxide

HRID 2119208Notes

Reaction equation

HRID 2119208 reaction equation
[CH3:1][N:2]1[C:7](=[O:8])[CH2:6][C:5]2[CH:9]=[CH:10][CH:11]=[CH:12][C:4]=2[S:3]1(=[O:14])=[O:13].[C:15](=O)([O-:17])[O-:16].C[Mg+2].Cl.C(OCC)C>CN(C)C=O>[CH3:1][N:2]1[C:7](=[O:8])[CH:6]([C:15]([OH:17])=[O:16])[C:5]2[CH:9]=[CH:10][CH:11]=[CH:12][C:4]=2[S:3]1(=[O:13])=[O:14]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 3283Diethyl EtherHCID 1201512-methyl-4-oxo-2H-1,2-benzothiazine-1,1-dioxideHCID 178526095HCID 178526095, compound

Product 1

HCID 538806993,4-dihydro-2-methyl-3-oxo-2H-1,2-benzothiazine-4-carboxylic acid 1,1-dioxideYield 97.9%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

In a four neck flask equipped with reflux condenser, stirrer, thermometer and calcium drying tube, 1.06 g (0.005 mole) 3,4-dihydro-2-methyl-3-oxo-2H-1,2-benzothiazine 1,1-dioxide and 2.6 g (0.02 mole) methylmagnesiumcarbonate in 20 ml N,N-dimethylformamide were added. The mixture was stirred at 90°-100° C. for 3 hours. The resulting solution was poured quickly into a mixture of 30 ml conc-hydrochloric acid, 70 g ice chips and 200 ml diethylether. After stirring the mixture for 10 minutes, the separated diethylether layer was evaporated in vacuo to obtain 1.25 g of 3,4-dihydro-2-methyl-3-oxo-2H-1,2-benzothiazine-4-carboxylic acid 1,1-dioxide. The obtained compound was dissolved in 20 ml benzene and to the solution, 1.3 ml thionyl chloride and 0.4 ml N,N-dimethylformamide were added.

Workup

  1. customIn a four neck flask equipped
  2. temperaturewith reflux condenser, stirrer
  3. stirringAfter stirring the mixture for 10 minutes
  4. customthe separated diethylether layer was evaporated in vacuo

Sources & evidence

ORD record
ord-2923c67e5c2a4f4c8c06c00df6a4453b
Source dataset
uspto-grants-1987_07
Patent number
US04683306

Reaction notes

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