Ammonia → 2H-1,3-Benzothiazine-2,4(3H)-dione

HRID 1390799Notes

Reaction equation

HRID 1390799 reaction equation
[C:1]([OH:10])(=O)[C:2]1[C:3](=[CH:5][CH:6]=[CH:7][CH:8]=1)[SH:4].C([N:13]([CH2:16]C)CC)C.ClC(OCC)=[O:20].N>O1CCCC1>[S:4]1[C:3]2[CH:5]=[CH:6][CH:7]=[CH:8][C:2]=2[C:1](=[O:10])[NH:13][C:16]1=[O:20]

Participants

6

Reactant 4

HCID 222AmmoniaHCID 54432-Mercaptobenzoic AcidHCID 8471TriethylamineHCID 10928Ethyl chloroformate

Product 1

HCID 34997932H-1,3-Benzothiazine-2,4(3H)-dioneYield 60.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

30 g of thiosalicylic acid and 39 g of triethylamine were dissolved in 125 ml of tetrahydrofuran. The mixed solution was maintained at a temperature of 0 - 5° C., to which 42 g of ethyl chloroformate was added dropwise. The system was allowed to stand for 30 minutes and then, 50 ml of aqueous ammonia (ammonia concentration: 25 - 30%) was added thereto. The resulting solution was allowed to stand over night at room temperatue (about 20 - 30° C.). Then, the solvent used was removed by distillation under reduced pressure, while the residue was filtered off, and recrystallized from ethanol. 21 g of 2H-1,3-benzothiazin-2,4(3H)-dione was obtained. The melting point of the product was 210 - 211° C. (In addition, this product can be also prepared by using as a starting material the ester derivatives of thiosalicylic acid, which are obtained using usual esterification reactions, in a similar manner as above.)

Workup

  1. additionwas added dropwise
  2. waitto stand over night at room temperatue (about 20 - 30° C.)
  3. customThen, the solvent used was removed by distillation under reduced pressure, while the residue
  4. filtrationwas filtered off
  5. customrecrystallized from ethanol

Sources & evidence

ORD record
ord-1ea3fc9dbbc74377b9aa7db299f541e9
Source dataset
uspto-grants-1979_02
Patent number
US04140532

Reaction notes

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