Carbon Dioxide → 4,4-Dimethyl-7-carboxythiochroman

HRID 2247983Notes

Reaction equation

HRID 2247983 reaction equation
Br[C:2]1[CH:13]=[CH:12][C:5]2[C:6]([CH3:11])([CH3:10])[CH2:7][CH2:8][S:9][C:4]=2[CH:3]=1.C([Li])CCC.[C:19](=[O:21])=[O:20].Cl>CCOCC.O1CCCC1.CCCCCC>[CH3:10][C:6]1([CH3:11])[C:5]2[CH:12]=[CH:13][C:2]([C:19]([OH:21])=[O:20])=[CH:3][C:4]=2[S:9][CH2:8][CH2:7]1

Participants

8

Reactant 4

HCID 280Carbon DioxideHCID 313Hydrochloric AcidHCID 223930997-Bromo-4,4-dimethylthiochromanHCID 178418339Butyllithium

Product 1

HCID 199355444,4-Dimethyl-7-carboxythiochroman

Reagents, catalysts & solvents 3

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Conditions

Temperature
-78 °C

Procedure

11 g of 7-bromo-3,4-dihydro-4,4-dimethyl-2H-1-benzothiopyran were dissolved in a mixture of 100 ml of ether and 10 ml of tetrahydrofuran and treated at -78° C. with 33 ml of a 1.6 molar solution of n-butyllithium in hexane. The reaction solution was held at -50° C. for 15 minutes, again cooled to -78° C. and gassed with carbon dioxide for 2 hours. Thereafter, the mixture was poured on to ice, acidified with 6N hydrochloric acid and extracted with ethyl acetate. The organic phases were washed with water, dried and evaporated. After recrystallization of the crude product from ethyl acetate/hexane, there were obtained 4.6 g of 3,4-dihydro-4,4-dimethyl-2H-1-benzothiopyran-7-carboxylic acid, melting point 202°-204° C.

Workup

  1. additionThereafter, the mixture was poured on to ice
  2. extractionextracted with ethyl acetate
  3. washThe organic phases were washed with water
  4. customdried
  5. customevaporated
  6. customAfter recrystallization of the crude product from ethyl acetate/hexane

Sources & evidence

ORD record
ord-2fd5bab02d5e4be2aeec1e932e294b87
Source dataset
uspto-grants-1991_08
Patent number
US05037825

Reaction notes

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