Water → 7-Methyl-1-benzothiophene

HRID 2111886Notes

Reaction equation

HRID 2111886 reaction equation
CO[CH:3](OC)[CH2:4][S:5][C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][C:7]=1[CH3:12].O>ClC1C=CC=CC=1>[CH3:12][C:7]1[C:6]2[S:5][CH:4]=[CH:3][C:11]=2[CH:10]=[CH:9][CH:8]=1

Participants

4

Reactant 2

HCID 962WaterHCID 66221073HCID 66221073, compound

Product 1

HCID 64285417-Methyl-1-benzothiopheneYield 77.6%

Reagents, catalysts & solvents 1

HCID 7964ChlorobenzeneSolvent2×

Procedure

To a heated (130° C.) solution of polyphosphoric acid (59 g) in chlorobenzene (500 ml) is added a solution of 1-[(2,2-dimethoxyethyl)thio]-2-methyl-benzene (23.4 g, 110 mmol) in chlorobenzene (125 ml) slowly over several hours and when addition is complete the reaction mixture is heated for a further 8 hours. The reaction mixture is cooled to ambient temperature and stirred for an additional 24 hours. Water is added, the layers are separated, and the aqueous layer is extracted with dichloromethane. The combined organic extracts are dried over anhydrous MgSO4, filtered, and concentrated. The crude material thus obtained is purified via flash chromatography on silica gel eluting with 100% pentane then 100% hexanes to afford 7-methyl-benzo[b]thiophene (12.65 g, 69%). 1H NMR (CDCl3): δ=7.71 (1H, d), 7.45 (1H, d), 7.39 (1H, d), 7.33 (1H, dd), 7.17 (1H, d), 2.61 (3H, s).

Workup

  1. additionwhen addition
  2. temperatureis heated for a further 8 hours
  3. customthe layers are separated
  4. extractionthe aqueous layer is extracted with dichloromethane
  5. dry with materialThe combined organic extracts are dried over anhydrous MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customThe crude material thus obtained
  9. customis purified via flash chromatography on silica gel eluting with 100% pentane

Sources & evidence

ORD record
ord-1bf06a88ebe848eeada0fbf1268a455e
Source dataset
uspto-grants-2009_04
Patent number
US07521462B2

Reaction notes

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