2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → Methyl (1,8-diethyl-4-oxo-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetate

Participants

Reaction Steps

The ester produced in step A (0.5g, 1.66 mmol) was dissolved in 5 ml of a 90% THF/water solution, and to this was added 2,3-dichloro-5,6-dicyano-1,4 -benzoquinone (0.75 g, 3.3 mmol., previously dissolved in 5 ml THF). This mixture was stirred overnight. The solvent was evaporated and 50 ml of ethyl acetate was added. The organic phase was extracted sequentially with 2.5N NaOH, distilled water and brine. The organic layer was separated, dried (MgSO4) and evaporated to produce 0.56 g of crude oil. The oil was flash chromatographed using CH2Cl2 --EtOAc 98-2 as eluant to yield 0.15 g of the desired product as a solid, m.p. 187°-189° C.

Provenance & Evidence