Dicyclohexylcarbodiimide → N-BOC-6-aminocaproic acid, N'-FMOC hydrazide

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Reaction Conditions

Reaction Steps

A 250 ml round bottom flask was charged with 4.190 g (0.0181 mol) of N-BOC-6-aminocaproic acid, 4.60 g of 9-fluorenylmethyl carbazate (FMOC), (prepared by the method of Carpino et. al., 1972, J. Org. Chem., 37: 3404) and 35 ml of N,N-dimethylformamide. The reaction solution was cooled to 0° C. and then 3.75 g (0.0182 mol) of 1,3-dicyclohexylcarbodiimide (Aldrich) was added. The reaction mixture was allowed to stir for 2 h at 0° C. The white precipitate which formed during this time was filtered off and the solvents evaporated under reduced pressure. The distillation residue was applied to a 225 cc pad of silica gel (Merck), which was then washed with 1L of chloroform. The product was then eluted from the column using 1 L of 50% methanol in chloroform. The solvents were evaporated from the desired eluent fractions to give 4.98 g (0.011 mol, 59% yield) of N-BOC-6-aminocaproic acid (N'-FMOC-hydrazide) as a yellow oil. 1H NMR (DMSO-d6) showed the peaks observed in the starting material and new protons in the aromatic region between 7-8 ppm (FMOC group).

Provenance & Evidence