反应详情

A solution of 734 milligrams (mg) [2 millimol (mmol)] of 7-β-galactosylcoumarin-3-carboxylic acid and 210 mg (2 mmol) of N-hydroxysuccinimide in 20 ml of dimethylformamide was cooled to -10° C. while stirring under an inert atmosphere. To this was added 412 mg (2 mmol) of dicyclohexyl carbodiimide. After 15 minutes at -10° C., a clear solution was obtained. The reaction was allowed to warm to room temperature and stirred for 2 hours. It was again cooled to -10° C. and the precipitate of dicyclohexyl urea removed by filtration under vacuum. The filtrate, now containing the activated ester (3), was placed in a dropping funnel and added dropwise over a 15 minute period to a 0° C. solution consisting of 346 mg (2 mmol) of 6-amino-2-n-propylhexanoic acid (2), n=4, and 0.5 ml of triethylamine in 20 ml of water. After 1 hour at 0° C., the reaction was allowed to warm to room temperature and stirred for 2 hours. Ten grams of silicic acid was added and the solvent removed on the rotary evaporator under high vacuum. The impregnated silicic acid was placed atop a column of 120 g of silicic acid packed in 3:2 (v:v) ethyl acetate:ethanol. The column was eluted with this solvent and 15 ml fractions were collected. Fractions 28 to 40 were combined, evaporated, and the residue recrystallized from ethanol to give 365 mg (35% yield) of the labeled conjugate (4), n=4, as cream colored crystals, mp 162° C.

1. customa clear solution was obtained
2. stirringstirred for 2 hours
3. temperatureIt was again cooled to -10° C.
4. customthe precipitate of dicyclohexyl urea removed by filtration under vacuum
5. additionThe filtrate, now containing the activated ester (3)
6. customwas placed in a dropping funnel
7. additionadded dropwise over a 15 minute period to a 0° C. solution
8. waitAfter 1 hour at 0° C.
9. temperatureto warm to room temperature
10. stirringstirred for 2 hours
11. customthe solvent removed on the rotary evaporator under high vacuum
12. washThe column was eluted with this solvent and 15 ml fractions
13. customwere collected
14. customevaporated
15. customthe residue recrystallized from ethanol