2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 4-Isopropyl-7,7-dimethyl-2',3',5',6',7,8-hexahydro-3H-spiro[furo[3,4-c]quinoline-1,4'-pyran]-3,9(6H)-dione

Participants

Reaction Conditions

Reaction Steps

3.12 g 3-Isobutyryl-1,8-dioxaspiro[4.5]dec-3-en-2-one and 2.13 g 3-amino-5,5-dimethylcyclohex-2-enone are mixed and heated to 200° C. for 10 minutes under a vacuo of 20 mbar. The mixture is cooled to room temperature, 15 ml ethylacetate are added and the mixture is stirred for 30 minutes. Then 15 ml petrole ether are added and the precipitate is isolated by filtration. The crude product is dissolved in 350 ml dichloromethane, treated with 2.46 g 2,3dichloro-5,6-dicyano-p-benzoquinone and stirred for 18 hours. 2 g Ascorbic acid are added and the mixture is stirred for 10 minutes. The it is washed for three times with water. The organic phase is dried with sodium sulphate and the solvents are evaporated in vacuo. The residue is chromatographed on silica gel (petrole ether/ethylacetate 100:0 to 50:50).

Provenance & Evidence