Dimethylformamide → p-nitrobenzyl (1R,5S,6S)-2-(1-{4-[N-methyl-N-(p-nitrobenzyloxycarbonyl)methyl-carbamoyl]-1,3-thiazol-2-yl}azetidin-3-yl)thio-6-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-1-methylcarbapen-2-em-3-carboxylate

Participants

Reaction Steps

To a suspension of p-nitrobenzyl (1R,5S,6S)-2-[1-(4-carboxy-1,3-thiazol-2-yl)azetidin-3-yl]thio-6-[(R)-1-t-butyldimethylsilyloxyethyl]-1-methylcarbapen-2-em-3-carboxylate (1.00 g, 1.51 mmol) (obtained as described in Reference Example 41(7)) and sarcosine p-nitrobenzyl ester hydrochloride (590 mg, 2.26 mmol) (obtained as described in Reference Example 43(2)) in dimethylformamide (30 ml) were added diethylphosphoryl cyanide (0.37 ml, 2.26 mmol) and triethylamine (0.95 ml, 6.80 mmol) in an ice bath under an atmosphere of nitrogen. The mixture was stirred at room temperature for 3 hours. After checking the completion of the reaction, the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium hydrogencarbonate solution. The obtained organic layer was washed successively with 0.5M aqueous hydrochloric acid solution, saturated aqueous sodium hydrogencarbonate solution and saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by chromatography on a silica gel column using hexane:ethyl acetate (1:1)→ethyl acetate as the eluant to afford p-nitrobenzyl (1R,5S,6S)-2-(1-{4-[N-methyl-N-(p-nitrobenzyloxycarbonyl)methyl-carbamoyl]-1,3-thiazol-2-yl}azetidin-3-yl)thio-6-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-1-methylcarbapen-2-em-3-carboxylate (997 mg, yield 76%).

Provenance & Evidence