Carbon Dioxide → 1,5-Dimethyl-3-oxabicyclo[3.2.0]heptane-2,4-dione

HRID 1702773Notes

Reaction equation

HRID 1702773 reaction equation
CC1=C(C)[C:4]([O:6]C1=O)=[O:5].[C:10]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)(=[O:17])C1C=CC=CC=1.C(=O)=O.C=C>ClCCl.[Hg].C(O)(C)C>[CH3:23][C:18]12[C:10](=[O:17])[O:6][C:4](=[O:5])[C:21]1([CH3:22])[CH2:20][CH2:19]2

Participants

8

Reactant 4

HCID 280Carbon DioxideHCID 3102BenzophenoneHCID 6325Ethylene2×HCID 13010Dimethylmaleic anhydride

Product 1

HCID 123563691,5-Dimethyl-3-oxabicyclo[3.2.0]heptane-2,4-dioneYield 1,201.2%

Reagents, catalysts & solvents 3

HCID 23931MercuryCatalystHCID 3776IsopropanolSolventHCID 6344DichloromethaneSolvent

Procedure

In a low temperature exposure unit equipped with a 125 W mercury lamp in a cooled immersion bath, stirrer and gas inlet pipe, 15 g (0.12 mole) of dimethyl maleic anhydride and 1 g (0.0054 mole) of benzophenone are dissolved in 300 ml of dichloromethane, and the solution is cooled by means of an external cooling bath with a mixture of isopropanol and dry ice to -60° to -70° C. Ethylene gas is then introduced over 1 hour and the reaction mixture is subsequently irradiated at the above temperature for 12 hours while introducing a weak flow of ethylene. The solvent is then evaporated off and the crude product is recrystallised from dichloromethane/n-hexane, affording 10 g of 1,2-dimethylcyclobutane-1,2-dicarboxylic anhydride (54% of theory) in the form of white crystals with a melting point of 84°-86° C.

Workup

  1. customthe reaction mixture is subsequently irradiated at the above temperature for 12 hours
  2. customThe solvent is then evaporated off
  3. customthe crude product is recrystallised from dichloromethane/n-hexane

Sources & evidence

ORD record
ord-2ecdc4013e0d43c298053098c5d94939
Source dataset
uspto-grants-1982_09
Patent number
US04349565

Reaction notes

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