Potassium Hydroxide → (R)-(+)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine

HRID 1439862Notes

Reaction equation

HRID 1439862 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C@@H:8]2[CH2:13][N:12](C(=O)[C@@H]3CCCN3S(C3C=CC4C(=CC=CC=4)C=3)(=O)=O)[C:11]3[CH:34]=[CH:35][CH:36]=[CH:37][C:10]=3[S:9]2)=[CH:4][CH:3]=1.[OH-].[K+]>C(O)C.O>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([C@@H:8]2[CH2:13][NH:12][C:11]3[CH:34]=[CH:35][CH:36]=[CH:37][C:10]=3[S:9]2)=[CH:6][CH:7]=1

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 54249707(R)-2-(4-Chlorophenyl)-4-[(S)-N-(2-naphthalene-sulfonyl)prolyl]-3,4-dihydro-2H-1,4-benzothiazine

Product 1

HCID 22847494(R)-(+)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazineYield 58.7%

Reagents, catalysts & solvents 1

HCID 19096565Water ethanolSolvent

Procedure

(R)-2-(4-Chlorophenyl)-4-[(S)-N-(2-naphthalenesulfonyl)prolyl]-3,4-dihydro-2H-1,4-benzothiazine (9.40 g, 0.017 mole) is suspended in ethanol-water (10:1, 188 ml), and thereto is added 86 % potassium hydroxide (11.2 g, 0.172 mole), and the mixture is refluxed for 30 minutes. The reaction mixture is poured into ice water and the mixture is extracted with ethyl acetate. The ethyl acetate layer is washed with water and saline, dried over sodium sulfate and distilled to remove the solvent. The residue is purified by silica gel column chromatography (CHC13) and thereafter recrystallized from ethyl acetate-hexane twice to give (R)-(+)-2-(4-chlorophenyl)-3,4-dihydro-2H-1,4-benzothiazine (2.61 g, 58%).

Workup

  1. temperaturethe mixture is refluxed for 30 minutes
  2. extractionthe mixture is extracted with ethyl acetate
  3. washThe ethyl acetate layer is washed with water and saline
  4. dry with materialdried over sodium sulfate
  5. distillationdistilled
  6. customto remove the solvent
  7. customThe residue is purified by silica gel column chromatography (CHC13)
  8. customrecrystallized from ethyl acetate-hexane twice

Sources & evidence

ORD record
ord-dd8f4106bf8145ac974452eea81d74c7
Source dataset
uspto-grants-1996_03
Patent number
US05496815

Reaction notes

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