Sodium hydride → Methyl 2-(5,5-dimethyl-5'-nitro-2'-oxospiro[[1,3]dioxane-2,3'-indoline]-1'-yl)acetate

Participants

Reaction Conditions

Reaction Steps

Crude 5,5-dimethyl-5′-nitrospiro[[1,3]dioxane-2,3′-indolin]-2′-one (obtained as described in Example 17, Step 1) (361 mg) was dissolved in dry DMF (11 ml) and cooled to 0° C.; NaH (60% w/w dispersion in mineral oil, 83 mg, 2.076 mmol) was added; and the mixture was stirred at 0° C. for 10 minutes (the reaction turned dark orange). Methyl 2-bromoacetate (0.144 ml, 1.557 mmol) was then added, the reaction was warmed to room temperature and stirred for 3 hours. The solvent was evaporated, water was added and extracted with EtOAc; the combined organic layers were dried over Na2SO4, filtered and evaporated. The crude was purified by flash chromatography on silica gel cartridge (petroleum ether:EtOAc from 95:5 to 85:15) affording methyl 2-(5,5-dimethyl-5′-nitro-2′-oxospiro[[1,3]dioxane-2,3′-indoline]-1′-yl)acetate (344 mg, 0.982 mmol, 84% yield). MS/ESI+ 351.0 [MH]+.

Provenance & Evidence