2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane → Ethyl 2-phenyl-4-thioxo-4H-1-benzopyran-8-carboxylate

HRID 1452310Notes

Reaction equation

HRID 1452310 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:15]2[O:14][C:13]([C:16]3[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=3)=[CH:12][C:11](=O)[C:10]=2[CH:9]=[CH:8][CH:7]=1)=[O:5])[CH3:2].COC1C=CC(P2SP(C3C=CC(OC)=CC=3)[S:32]2)=CC=1>C1(C)C=CC=CC=1>[C:16]1([C:13]2[O:14][C:15]3[C:6]([C:4]([O:3][CH2:1][CH3:2])=[O:5])=[CH:7][CH:8]=[CH:9][C:10]=3[C:11](=[S:32])[CH:12]=2)[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1

Participants

4

Reactant 2

HCID 127328752,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetaneHCID 199725494h-1-Benzopyran-8-carboxylic acid,4-oxo-2-phenyl-,ethyl ester

Product 1

HCID 19972750Ethyl 2-phenyl-4-thioxo-4H-1-benzopyran-8-carboxylateYield 123.2%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of 4.0g of 8-ethoxycarbonyl-2-phenyl-4-oxo-4H-1-benzopyran (prepared as described in Da Re et al., Ber. 1962, 99 (1966)) and 3.55 g of 2,4-bis-(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane (Lawesson's reagent) in 68 ml of toluene was stirred at reflux for 2 hours. The reaction mixture was cooled to room temperature and evaporated to dryness in vacuo. The crude residue was rinsed with petroleum ether and filtered to give a solid. The material was purified by flash chromatography on silica gel, eluting with a petroleum ether - ethyl acetate gradient (9:1 to 7:3). Evaporation in vacuo of the collected fractions yielded 3.99 g of pure title compound, melting at 161°-163° C. after recrystallization from cyclohexane.

Workup

  1. temperatureat reflux for 2 hours
  2. customevaporated to dryness in vacuo
  3. washThe crude residue was rinsed with petroleum ether
  4. filtrationfiltered
  5. customto give a solid
  6. customThe material was purified by flash chromatography on silica gel
  7. washeluting with a petroleum ether - ethyl acetate gradient (9:1 to 7:3)
  8. customEvaporation in vacuo of the collected fractions

Sources & evidence

ORD record
ord-d57f514d6f16462c87d8231445b8069b
Source dataset
uspto-grants-1997_02
Patent number
US05605896

Reaction notes

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