Hydrochloric Acid → (3AS,6aR)-1,3-dibenzyltetrahydro-1H-furo(3,4-d)imidazole-2,4-dione

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Reaction Steps

A solution of (4S,5R)-1,3-dibenzyl-5-methoxycarbonyl-2-oxoimidazolidine-4-carboxylic acid (mp., 146°-150° C., [α]36525 =-27.6° at c=1 in DMF, 3.68 g) in isopropanol (10 ml) and 1,2-dichloroethane (60 ml) was added dropwise to a mixture of sodium borohydride (760 mg) and isopropanol (20 ml) at 5°-10° C. over a period of 15 minutes. The obtained mixture was allowed to warm up to room temperature and to react at the same temperature for 20 hours. Then, 1N hydrochloric acid (50 ml) was added to the reaction mixture. The mixture was stirred at 55°-60° C. for 30 minutes. Aqueous layer was separated from organic layer and extracted once with 1,2-dichloroethane (50 ml). The organic layers were combined, washed successively with water, 5% aqueous sodium hydrogen carbonate, dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give (3aS,6aR)-1,3-dibenzylhexahydro-1H-furo[3,4-d]imidazole-2,4-dione (3.12 g). M.P., 116°-117° C. [α]D25 =+61.0° (c=1, CHCl3).

Provenance & Evidence