Potassium cyanate → 4-Cyano-2,3,4,9-tetrahydrothiopyrano[2,3-b]indole

HRID 127509Notes

Reaction equation

HRID 127509 reaction equation
[CH2:1]([S:4][C:5]1[NH:6][C:7]2[C:12]([CH:13]=1)=[CH:11][CH:10]=[CH:9][CH:8]=2)[C:2]#[CH:3].[O-][C:15]#[N:16].[K+]>C(O)C.C(N(CC)CC)C.O>[C:15]([CH:3]1[C:13]2[C:12]3[C:7](=[CH:8][CH:9]=[CH:10][CH:11]=3)[NH:6][C:5]=2[S:4][CH2:1][CH2:2]1)#[N:16]

Participants

6

Reactant 2

HCID 11378442Potassium cyanateHCID 202847712-[(Prop-2-yn-1-yl)sulfanyl]-1H-indole

Product 1

HCID 147356314-Cyano-2,3,4,9-tetrahydrothiopyrano[2,3-b]indoleYield 69%

Reagents, catalysts & solvents 3

HCID 702EthanolSolvent2×HCID 962WaterSolventHCID 8471TriethylamineSolvent

Procedure

The product of the above (2) (13.2 g) is dissolved in a mixture of ethanol (300 ml) and triethylamine (20 ml). The solution is refluxed for 1 hour and further 2 hours after addition of a solution of potassium cyanate (25 g) in a mixture of ethanol (170 ml) and water (80 ml) and evaporated to remove the solvent. The residue is extracted with ether after addition of water. The extract is washed with water, dried and evaporated to remove the solvent. The oily residue (15 g) is chromatographed on an column of silica gel (450 g) and eluted with benzene. The eluate is condensed to give the title compound as crystals melting at 125°-126° C. Yield: 69%

Workup

  1. temperatureThe solution is refluxed for 1 hour and further 2 hours
  2. customevaporated
  3. customto remove the solvent
  4. extractionThe residue is extracted with ether
  5. additionafter addition of water
  6. washThe extract is washed with water
  7. customdried
  8. customevaporated
  9. customto remove the solvent
  10. customThe oily residue (15 g) is chromatographed on an column of silica gel (450 g)
  11. washeluted with benzene
  12. customcondensed

Sources & evidence

ORD record
ord-4667abd387504f358b99fae953c62ba0
Source dataset
uspto-grants-1981_03
Patent number
US04256640

Reaction notes

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