Hydrochloric Acid → p-[2-(3,4-dihydro-4,4-dimethyl-2H-1-benzothiopyran-7-yl)propenyl]benzoic acid

HRID 373540Notes

Reaction equation

[CH3:1][C:2]1([CH3:26])[C:7]2[CH:8]=[CH:9][C:10]([C:12]([CH3:25])=[CH:13][C:14]3[CH:24]=[CH:23][C:17]([C:18]([O:20]CC)=[O:19])=[CH:16][CH:15]=3)=[CH:11][C:6]=2[S:5][CH2:4][CH2:3]1.[OH-].[K+].Cl>C(O)C.O>[CH3:1][C:2]1([CH3:26])[C:7]2[CH:8]=[CH:9][C:10]([C:12]([CH3:25])=[CH:13][C:14]3[CH:15]=[CH:16][C:17]([C:18]([OH:20])=[O:19])=[CH:23][CH:24]=3)=[CH:11][C:6]=2[S:5][CH2:4][CH2:3]1

Participants

Conditions

Temperature: 50 °C

Procedure

1 g of the thus-obtained ester was dissolved in 20 ml of ethanol and treated with a solution of 1.6 g of potassium hydroxide in 10 ml of water. After heating to 50° C. for 2 hours, the mixture was poured on to ice, acidified with 2N hydrochloric acid and extracted repeatedly with ethyl acetate. The crystalline residue obtained after evaporation was recrystallized from acetic acid. There was obtained 0.6 g of p-[2-(3,4-dihydro-4,4-dimethyl-2H-1 -benzothiopyran-7-yl)propenyl]benzoic acid, m.p. 255°-257° C.

Workup

additionthe mixture was poured on to ice
extractionextracted repeatedly with ethyl acetate
customThe crystalline residue obtained
customafter evaporation
customwas recrystallized from acetic acid

Sources & evidence

ORD record: ord-1dda6590363e4a1cb74a8aabd8b849c7
Source dataset: uspto-grants-1992_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05164387

Reaction notes

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