تفاعل #48034

معادلة التفاعل

ethyl 2-chloro[(4-chlorophenyl) hydrazono]acetate

styrene

triethylamine

→

ethyl 1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylate

المردود 94.0%

المذيبات

benzene

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةthe resulting solution is heated
2. 2
   درجة الحرارةat reflux temperature for 1 hour
3. 3
   أخرىthe formed precipitate is removed by filtration
4. 4
   غسيلwashed with toluene
5. 5
   تركيزThe filtrate is concentrated in vacuo
6. 6
   أخرىpurified by flash chromatography (silica gel, dichloromethane)

الإجراء التجريبي

Part B: To a stirred boiling solution of ethyl 2-chloro[(4-chlorophenyl) hydrazono]acetate (22.95 gram, 0.088 mol) and styrene (30.3 ml, 0.264 mol) in benzene (140 ml) is added triethylamine (34.3 ml, 0.247 mol) and the resulting solution is heated at reflux temperature for 1 hour. The resulting solution is cooled to room temperature and the formed precipitate is removed by filtration and washed with toluene. The filtrate is concentrated in vacuo and purified by flash chromatography (silica gel, dichloromethane) to give ethyl 1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylate (27.2 gram, 94% yield) as a syrup which slowly solidifies on standing. 1H-NMR (200 MHz, CDCl3): 1.38 (t, J=7 Hz, 3H), 3.06 (dd, J=18 and 7 Hz, 1H), 3.73 (dd, J=18 and 13 Hz, 1H), 4.33 (q, J=7 Hz, 2H), 5.38 (dd, J=13 and 7 Hz, 1H), 7.02 (br d, J=8 Hz, 2H), 7.08-7.40 (m, 7H).

المصدر