Hydrochloric Acid → 3-(4-chlorophenyl)-2,3-dihydro1H-naphtho[2,1-b][1,4]thiazine

HRID 1198442Notes

Reaction equation

HRID 1198442 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH:8]2[S:13][C:12]3[CH:14]=[CH:15][C:16]4[C:21]([C:11]=3[NH:10][C:9]2=O)=[CH:20][CH:19]=[CH:18][CH:17]=4)=[CH:4][CH:3]=1.[BH4-].[Na+].Cl.C(=O)([O-])[O-].[K+].[K+]>O1CCCC1.CO>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([CH:8]2[S:13][C:12]3[CH:14]=[CH:15][C:16]4[C:21]([C:11]=3[NH:10][CH2:9]2)=[CH:20][CH:19]=[CH:18][CH:17]=4)=[CH:6][CH:7]=1

Participants

7

Reactant 4

HCID 313Hydrochloric Acid2×HCID 11430Potassium CarbonateHCID 4311764Sodium borohydrideHCID 189844403-(4-chlorophenyl)-1H-naphtho[2,1-b][1,4]thiazin-2(3H)-one

Product 1

HCID 189844023-(4-chlorophenyl)-2,3-dihydro1H-naphtho[2,1-b][1,4]thiazineYield 88%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 3-(4-chlorophenyl)-1H-naphtho[2,1-b][1,4]thiazin-2(3H)-one (38.45 g) and sodium borohydride (22.32 g) in tetrahydrofuran (1.0 liter) is added dropwise with stirring boron trifluoride etherate complex (100 ml) at room temperature, and the mixture is refluxed for 2 hours. After cooling, to the mixture are added methanol (200 ml), 10 hydrochloric acid (300 ml) and conc. hydrochloric acid (150 ml) in this order and the mixture is further refluxed for 4 hours. To the reaction mixture is added ice water and the mixture is made alkaline with potassium carbonate and extracted with ethyl acetate. The ethyl acetate layer is washed, dried and distilled to remove the solvent. The residue is recrystallized from tetrahydrofuran-n-hexane to give 3-(4-chlorophenyl)-2,3-dihydro-1H-naphtho[2,1-b][1,4]thiazine (32.3 g, yield 88%) as crystals.

Workup

  1. temperaturethe mixture is refluxed for 2 hours
  2. temperatureAfter cooling, to the mixture
  3. temperaturethe mixture is further refluxed for 4 hours
  4. extractionextracted with ethyl acetate
  5. washThe ethyl acetate layer is washed
  6. customdried
  7. distillationdistilled
  8. customto remove the solvent
  9. customThe residue is recrystallized from tetrahydrofuran-n-hexane

Sources & evidence

ORD record
ord-8a20a21ac36c4a8f8ac9ff1a44967d6e
Source dataset
uspto-grants-1994_01
Patent number
US05281592

Reaction notes

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