2,6-Pyridinedicarbonyl
dichloride (0.00961 mol, Wako Chemical Ltd.) and triethylamine (0.0193
mol, Kanto Chemical Co., Inc.) were dissolved in THF (40 mL, Kanto
Chemical Co., Inc.) in a 100 mL round-bottom flask. After the mixture
was cooled in an ice bath, THF (5 mL) containing N-ethylmethylamine, diethylamine, N-methylpropylamine,
or N-ethylpropylamine (0.0192 mol, Tokyo Chemical
Industry Co., Ltd.) was slowly added using a dropping funnel. Additional
THF (10 mL) was then further loaded. The mixture was stirred in the
ice bath for 1 h and at RT overnight. After removing the white precipitate
by filtration, the supernatant was concentrated using a rotary evaporator.
The residue was dissolved in dichloromethane (30 mL) and mixed with
2 M HCl(aq) (2 mL). The organic layer was separated, mixed with a
small portion of K2CO3 and MgSO4,
and rested for 15 min. Then, solid materials were removed by filtration.
Any volatile material in the filtrate was removed using the rotary
evaporator.
dichloride (0.00961 mol, Wako Chemical Ltd.) and triethylamine (0.0193
mol, Kanto Chemical Co., Inc.) were dissolved in THF (40 mL, Kanto
Chemical Co., Inc.) in a 100 mL round-bottom flask. After the mixture
was cooled in an ice bath, THF (5 mL) containing N-ethylmethylamine, diethylamine, N-methylpropylamine,
or N-ethylpropylamine (0.0192 mol, Tokyo Chemical
Industry Co., Ltd.) was slowly added using a dropping funnel. Additional
THF (10 mL) was then further loaded. The mixture was stirred in the
ice bath for 1 h and at RT overnight. After removing the white precipitate
by filtration, the supernatant was concentrated using a rotary evaporator.
The residue was dissolved in dichloromethane (30 mL) and mixed with
2 M HCl(aq) (2 mL). The organic layer was separated, mixed with a
small portion of K2CO3 and MgSO4,
and rested for 15 min. Then, solid materials were removed by filtration.
Any volatile material in the filtrate was removed using the rotary
evaporator.