N-叔丁氧羰基-L-天冬氨酸酐

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 23.3 g N-t-butyloxycarbonyl-L-aspartic acid in 150 mL of tetrahydrofuran was added portionwise 20.6 g of N,N-dicyclohexyl-carbodiimide at 0° C. and overnight at room temperature. The precipitated dicyclohexyl urea was filtered off and all solvent was evaporated under reduced pressure. The oily residue was crystallized from acetone/hexane to give 18.24 g of anydride as white needles. overnight at room temperature The precipitated dicyclohexyl urea was filtered off all solvent was evaporated under reduced pressure The oily residue was crystallized from acetone/hexane to give 18.24 g of anydride as white needles

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 23.3 g N-t-butyloxycarbonyl-L-aspartic acid in 150 mL of tetrahydrofuran was added portionwise 20.6 g of N,N-dicyclohexyl-carbodiimide at 0° C. and overnight at room temperature. The precipitated dicyclohexyl urea was filtered off and all solvent was evaporated under reduced pressure. The oily residue was crystallized from acetone/hexane to give 18.24 g of anydride as white needles. overnight at room temperature The precipitated dicyclohexyl urea was filtered off all solvent was evaporated under reduced pressure The oily residue was crystallized from acetone/hexane to give 18.24 g of anydride as white needles

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Due to its low cost, L-aspartic acid appears to be the most attractive starting material for the preparation of (S)-3-amino-1-substituted-pyrrolidines. The literature method from L-aspartate (D. T. Witiak, loc. cit.) involves treatment of N-boc-L-aspartate with acetic anhydride to give (S)-3-(tert-butoxycarbonylamino)succinic anhydride followed by addition of a primary amine and ring closure with heat to give the succinimide, (S)-3-(tert-butoxycarbonylamino)-1-substituted pyrrolidine-2,5-dione. The latter is then reduced and deblocked to give the 1-substituted-3-aminopyrrolidine in low overall yield. From our experience with this method some racemization takes place when the blocking group is p-toluenesulfonyl(tosyl) and the primary amine is benzylamine.

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Due to its low cost, L aspartic acid appears to be the most attractive starting material for the preparation of (S)-3-amino-1-substituted-pyrrolidines. The literature method from L-aspartate (D. T. Witiak, loc. cit.) involves treatment of N-boc-L-aspartate with acetic anhydride to give (S)-3-(tert butoxycarbonylamino)succinic anhydride followed by addition of a primary amine and ring closure with heat to give the succinimide, (S)-3-(tert-butoxycarbonylamino)-1-substituted pyrrolidine-2,5-dione. The latter is then reduced and deblocked to give the 1-substituted-3-aminopyrrolidine in low overall yield. From our experience with this method some racemization takes place when the blocking group is p-toluenesulfonyl(tosyl) and the primary amine is benzylamine.

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 23.3 g N-t-butyloxycarbonyl-L-aspartic acid in 150 mL of tetrahydrofuran was added portionwise 20.6 g of N,N-dicyclohexyl-carbodiimide at 0° C. and overnight at room temperature. The precipitated dicyclohexyl urea was filtered off and all solvent was evaporated under reduced pressure. The oily residue was crystallized from acetone/hexane to give 18.24 g of anydride as white needles. overnight at room temperature The precipitated dicyclohexyl urea was filtered off all solvent was evaporated under reduced pressure The oily residue was crystallized from acetone/hexane to give 18.24 g of anydride as white needles