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

HRID 2119205Notes

Reaction equation

HRID 2119205 reaction equation
[CH3:1][N:2]1[CH2:7][C:6](=[O:8])[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[CH:7]([C:15]([OH:17])=[O:16])[C:6](=[O:8])[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 76017542-methyl-2,3-dihydro-4H-1,2-benzothiazin-4-one 1,1-dioxideHCID 178526095HCID 178526095, compound

Product 1

HCID 130512493,4-Dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylic Acid-1,1-dioxideYield 94.2%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To 6.34 g (0.03 mole) 3,4-dihydro-2-methyl-4-oxo-1,2-benzothiazine 1,1-dioxide, 19.5 g (0.15 mole) methylmagnesiumcarbonate in 150 ml N,N-dimethyl formamide were added. The mixture was stirred at 140°-150° C. for 2 hours. The resulting solution was poured quickly into a mixture of 200 ml conc-hydrochloric acid, 200 g ice chips and 500 ml diethyl ether. After stirring the mixture for 10 minutes, the diethylether layer was separated and the separated diethyl ether solution was evaporated in vacuo. The precipitated pale yellow crystals were filtered and recrystallized in dilute methanol solution to obtain 7.21 g of the title compound as white crystals. Yield: 94%

Workup

  1. stirringAfter stirring the mixture for 10 minutes
  2. customthe diethylether layer was separated
  3. customthe separated diethyl ether solution was evaporated in vacuo
  4. filtrationThe precipitated pale yellow crystals were filtered
  5. customrecrystallized in dilute methanol solution

Sources & evidence

ORD record
ord-bebfab3267b043beb133eb149e204ab8
Source dataset
uspto-grants-1987_07
Patent number
US04683306

Reaction notes

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