3-[(1H-Indol-3-yl)sulfanyl]prop-2-enoic acid → Thiopyrano[3,2-b]indol-4(5H)-one

HRID 437780Notes

Reaction equation

HRID 437780 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[C:3]([S:10][CH:11]=[CH:12][C:13]([OH:15])=O)=[CH:2]1>C(O)(=O)C>[S:10]1[C:3]2[C:4]3[CH:5]=[CH:6][CH:7]=[CH:8][C:9]=3[NH:1][C:2]=2[C:13](=[O:15])[CH:12]=[CH:11]1

Participants

3

Reactant 1

HCID 544439283-[(1H-Indol-3-yl)sulfanyl]prop-2-enoic acid

Product 1

HCID 20326608Thiopyrano[3,2-b]indol-4(5H)-oneYield 53.7%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of 76.7 g (0.35 mole) of 3-(indol-3 ylthio) acrylic acid in 4 liters of 10% polyphosphoric acid in acetic acid is stirred at room temperature for 65 hours. The supernatent is decanted from the sticky precipitate, which is partitioned between chloroform and 5% NaOH solution. The organic phase is washed with water, dried, evaporated and the residue recrystallized from 3 liters of 95% ethanol to give 37.8 g of product, mp 242°-243° C.

Workup

  1. customThe supernatent is decanted from the sticky precipitate, which
  2. customis partitioned between chloroform and 5% NaOH solution
  3. washThe organic phase is washed with water
  4. customdried
  5. customevaporated
  6. customthe residue recrystallized from 3 liters of 95% ethanol

Sources & evidence

ORD record
ord-81e187c3b3c143088521aa23533f1ccc
Source dataset
uspto-grants-1977_06
Patent number
US04032537

Reaction notes

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