1,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochloride → (R)-3-[dimethyl-(1,1,2-trimethyl-propyl)silanyloxy]-5-methoxy-6-methyl-2-[2-(3-methyl-1,2,4-oxadiazol-5-yl)-2-(2-trityloxy-acetylamino]-ethylsulfanylmethyl]-benzoic acid allyl ester

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1.07 g of (R)-2-[2-amino-2-(3-methyl-1,2,4-oxadiazol-5-yl)-ethylsulfanylmethyl]-3-[dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-5-methoxy-6-methylbenzoic acid allyl ester and 0.96 g of trityloxy-acetic acid in 15 ml of acetonitrile, cooled to 0° C., were added 0.58 g of N-(dimethylamino-propyl)-N'-ethyl-carbodiimide hydrochloride. The mixture was stirred at 0° C. for 4 h, then diluted with 30 ml of ethyl acetate, and washed successively with 0.5N hydrochloric acid, water, 5% sodium bicarbonate solution, and brine. The organic layer was dried over sodium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel using ethyl acetate/hexane (1:1, v/v) as eluent to yield 1.42 g of (R)-3-[dimethyl-(1,1,2-trimethyl-propyl)silanyloxy]-5-methoxy-6-methyl-2-[2-(3-methyl-1,2,4-oxadiazol-5-yl)-2-(2-trityloxy-acetylamino]-ethylsulfanylmethyl]-benzoic acid allyl ester as a foam.

Provenance & Evidence