反应详情

To a solution of 75 g 5-phenyl-2-picoline N-oxide from Step 1 in 375 mL of CH2Cl2 were added simultaneously a solution of 41.5 mL phosphoryl chloride in 150 mL of CH2Cl2 and a solution of 62 mL Et3N in 150 mL of CH2Cl2. The rate of addition was adjusted so that the reaction reached reflux temperature. The addition completed, the reaction was poured into a solution of NH4OAc (25%), stirred 30 minutes and extracted with EtOAc. The organic layer was dried over MgSO4, filtered on a silica gel bed and evaporated to dryness. The resulting solid was recrystallised from petroleum ether (30°-60° C.) to afford pure title product, m.p.: 73° C. The filtrate was chromatographed on silica gel (hexane/EtOAc 9:1) to give the title product along with 4-chloro-5-phenyl-2-picoline and 6-chloro-5-phenyl-2-picoline.

1. additionThe rate of addition
2. temperaturereached reflux temperature
3. additionThe addition
4. extractionextracted with EtOAc
5. dry with materialThe organic layer was dried over MgSO4
6. filtrationfiltered on a silica gel bed
7. customevaporated to dryness
8. customThe resulting solid was recrystallised from petroleum ether (30°-60° C.)