Thioglycolic Acid → 3-methylbenzo[b]thiophene-2-carboxylic acid

HRID 1739454Notes

Reaction equation

HRID 1739454 reaction equation
[OH-].[K+].[C:3]([OH:7])(=[O:6])[CH2:4][SH:5].Cl[C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[C:15](=O)[CH3:16]>O.CCCC[N+](CCCC)(CCCC)CCCC.[Br-]>[CH3:16][C:15]1[C:10]2[CH:11]=[CH:12][CH:13]=[CH:14][C:9]=2[S:5][C:4]=1[C:3]([OH:7])=[O:6]

Participants

6

Reactant 3

HCID 1133Thioglycolic AcidHCID 14797Potassium HydroxideHCID 72864Ethanone, 1-(2-chlorophenyl)-

Product 1

HCID 8218683-methylbenzo[b]thiophene-2-carboxylic acidYield 27%

Reagents, catalysts & solvents 2

HCID 74236Tetrabutylammonium BromideCatalystHCID 962WaterSolvent

Conditions

Temperature
253 fahrenheit

Procedure

Potassium hydroxide (12.5 g) was dissolved in water (105 ml) in a glass pressure bottle cooled in an ice bath. Then under a blanket of nitrogen, thioglycolic acid (7 ml) was added to the glass pressure bottle, to produce a reaction mixture. 2'-chloroacetophenone (12 g, 97%, 0.075 mol) and TBAB (0.5 g) were then added to the reaction mixture. The glass pressure bottle was then sealed and heated to 253° F. for 6 hours at 18 psi. The reaction was shut down and left overnight. Heating was then resumed at 270° F. at 30 psi for six hours and then cooled to ambient temperature. After the bottle was opened, the reaction mixture was washed with ether to remove organics, and acidified with hydrochloric acid to give 3.9 g of crude 3-methyl 2-benzo[b]thiophenecarboxylic acid (27% yield, mp>200° C.).

Workup

  1. temperaturecooled in an ice bath
  2. customto produce a reaction mixture
  3. customThe glass pressure bottle was then sealed
  4. temperatureHeating
  5. waitwas then resumed at 270° F. at 30 psi for six hours
  6. temperaturecooled to ambient temperature
  7. washthe reaction mixture was washed with ether
  8. customto remove organics

Sources & evidence

ORD record
ord-1126952c32124634a36f17889306008e
Source dataset
uspto-grants-1999_10
Patent number
US05965749

Reaction notes

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