1,5-Diiodopentane → 3-(4-Bromobutyl)-1-thia-3-azaspiro[5.4]decan-4-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-(4-bromobutyl)-4-thiazolidinone (25 g) in THF (350 ml) cooled to -60° C. was added 1,5-diiodopentane (100 g), and the resultant slurry was cooled to -65° C. A solution of lithium bis(trimethylsily)amide (0.220 mole) in hexanes (220 ml) was added dropwise, during which the internal temperature was maintained at or below -55° C. The addition was complete within 30 minutes. The mixture was stirred for additional 15 minutes at the same temperature and thereafter warmed to 0° C. with the aid of an ice bath. The mixture was stirred for additional 20 minutes and thereafter quenched with 500 ml of 0.5N HCl solution. The resultant mixture was placed under vacuum to remove some of the THF and thereafter extracted with ether (350 ml, 2×250 ml). The combined extracts were washed successively with water (400 ml) and brine (400 ml), dried with Na2SO4 and concentrated to a liquid. The liquid was chromatographed (2 silica gel columns) using 20-60% ethyl acetate/hexane as an eluent to obtain about 20.5 g of solid product.

Provenance & Evidence