Phosphoric Acid → Ethyl 5-bromo-6-methoxybenzo[b]thiophene-3-carboxylate

HRID 581981Notes

Reaction equation

HRID 581981 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([S:10][CH2:11][C:12](=O)[C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:6]=[CH:7][C:8]=1[Br:9].O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.P(=O)(O)(O)O>ClC1C=CC=CC=1>[Br:9][C:8]1[C:3]([O:2][CH3:1])=[CH:4][C:5]2[S:10][CH:11]=[C:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[C:6]=2[CH:7]=1

Participants

5

Reactant 3

HCID 1004Phosphoric AcidHCID 14812Phosphorus oxide (P4O10)HCID 54335313HCID 54335313, compound

Product 1

HCID 53817228Ethyl 5-bromo-6-methoxybenzo[b]thiophene-3-carboxylateYield 27.1%

Reagents, catalysts & solvents 1

HCID 7964ChlorobenzeneSolvent

Procedure

Ethyl 3-(3-methoxy-4-bromophenylthio)-2-oxopropanoate (D3) (3.7 g, 11 mmoles) in chlorobenzene (25 ml) was treated with phosphorus pentoxide (11.1 g, 78 mmoles) and 85% phosphoric acid (5.5 ml). The mixture was heated under reflux for 6 hrs. The mixture was allowed to cool and then partitioned between water (150 ml) and dichloromethane. The organics were washed several times with water then dried (Na2SO4). Evaporation to dryness followed by flash chromatography on TLC silica gel eluting with dichloromethane/60-80 petrol-ether 1:1 gave the title compound (D4) (0.94 g, 27%).

Workup

  1. temperatureThe mixture was heated
  2. temperatureunder reflux for 6 hrs
  3. temperatureto cool
  4. custompartitioned between water (150 ml) and dichloromethane
  5. washThe organics were washed several times with water
  6. dry with materialthen dried (Na2SO4)
  7. customEvaporation to dryness

Sources & evidence

ORD record
ord-e2d1c530b32b4f6c901b7b914bb02152
Source dataset
uspto-grants-1999_07
Patent number
US05922733

Reaction notes

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