Hydrochloric Acid → 5-Chloro-2,3-dihydro-1,4-benzothiazine-3-thione

HRID 1157002Notes

Reaction equation

HRID 1157002 reaction equation
[Cl:1][C:2]1[C:7]2[NH:8][C:9](=O)[CH2:10][S:11][C:6]=2[CH:5]=[CH:4][CH:3]=1.P12(SP3(SP(SP(S3)(S1)=S)(=S)S2)=S)=[S:14].Cl>N1C=CC=CC=1>[Cl:1][C:2]1[C:7]2[NH:8][C:9](=[S:14])[CH2:10][S:11][C:6]=2[CH:5]=[CH:4][CH:3]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 14817Phosphorus sulfide (P2S5)HCID 128992635-chloro-2H-benzo[b][1,4]thiazin-3(4H)-one

Product 1

HCID 128992815-Chloro-2,3-dihydro-1,4-benzothiazine-3-thioneYield 195.8%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Conditions

Temperature
120 °C

Procedure

5-Chloro-2,3-dihydro-1,4-benzothiazine-3-one (2.0 g) and phosphorus pentasulfide (2.0 g) were added to pyridine (5 ml), followed by stirring at 120° C. for 20 minutes. The reaction mixture was then poured into a dilute hydrochloric acid (50 ml), and the precipitated crystals were filtered, washed with water, dried and recrystallized from ethanol to obtain 1.9 g of the objective 5-chloro-2,3-dihydro-1,4-benzothiazine-3-thione (m.p. 138°-140° C.).

Workup

  1. filtrationthe precipitated crystals were filtered
  2. washwashed with water
  3. customdried
  4. customrecrystallized from ethanol

Sources & evidence

ORD record
ord-5c18749f76c543fe9413ef6b1c2d7733
Source dataset
uspto-grants-1982_06
Patent number
US04337357

Reaction notes

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