反应详情

A mixture of 8.0 g of 4',5'-dihydrospiro[benzo[b]-thiophene-2(3H),3'(2'H)-furan]-3,2'-dione, 2.3 g of sodium chloride and 20 ml of dimethylsulfoxide is stirred in nitrogen streams at 155°-160° C. for 3.5 hours. The reaction mixture is poured in ice-water, the resultant precipitate recovered by filtration and rinsed, and the residue recrystallized from methanol. By the above procedure there is obtained 5.2 g of 3-oxo-2,3-dihydro[1]benzothiophene-2-spirocyclopropane as colorless platelets melting at 70° C.

1. filtrationthe resultant precipitate recovered by filtration
2. washrinsed
3. customthe residue recrystallized from methanol