3-(2,5-Dimethyl-phenylsulfanyl)-propionic acid → 5,8-Dimethyl-3,4-dihydro-2H-1-benzothiopyran-4-one

HRID 1602768Notes

Reaction equation

HRID 1602768 reaction equation
[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[CH:4][C:3]=1[S:9][CH2:10][CH2:11][C:12]([OH:14])=O>S(=O)(=O)(O)O>[CH3:8][C:5]1[C:4]2[C:12](=[O:14])[CH2:11][CH2:10][S:9][C:3]=2[C:2]([CH3:1])=[CH:7][CH:6]=1

Participants

3

Reactant 1

HCID 167883143-(2,5-Dimethyl-phenylsulfanyl)-propionic acid

Product 1

HCID 216965945,8-Dimethyl-3,4-dihydro-2H-1-benzothiopyran-4-oneYield 51.4%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

530 mL of concentrated sulfuric acid was added to 24.91 g (0.119 mol) of the title compound of Step A while being cooled with an acetone/ice bath. The ice bath was removed, the mixture stirred for 1 hr and was then poured over crushed ice. The aqueous layer was extracted with a 1:9 mixture of diethyl ether:hexane (6×500 mL), dried (MgSO4), filtered, and evaporated to dryness to yield 11.75 g of the title compound of Step B as an oil. 1H NMR (CDCl3): δ2.3 (s,3H), 2.6 (s,3H), 2.97 (m,2H), 3.2 (m,2H), 6.9-7.1 (m,2H).

Workup

  1. temperaturewhile being cooled with an acetone/ice bath
  2. customThe ice bath was removed
  3. additionwas then poured
  4. customover crushed ice
  5. extractionThe aqueous layer was extracted with a 1:9 mixture of diethyl ether
  6. dry with materialhexane (6×500 mL), dried (MgSO4)
  7. filtrationfiltered
  8. customevaporated to dryness

Sources & evidence

ORD record
ord-d4991a37bb4846419b69757d97e9107e
Source dataset
uspto-grants-1999_11
Patent number
US05985799

Reaction notes

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