反应详情

840 mg of 4-formyl-l-methyl pyridinium benzensulfonate were added to a solution of 740 mg of the product of Step A, 15 ml of methylene chloride and 5 ml of dimethylformamide and the reaction mixture was stirred for 45 minutes. 1 ml of diazobicyclo[5,4,0]-undec-7-ene was added and the reaction mixture was stirred for 45 minutes. After cooling down to 5-l0° C., 5 ml of a saturated aqueous solution of oxalic acid were added and the reaction mixture was stirred for 1 hour. Extraction took place with methylene chloride followed by washing with a solution of sodium bicarbonate, drying, filtering and bringing to dryness to obtain 630 mg of product which was chromatographed on silica, eluting with a cyclohexane-ethyl acetate (9-1) mixture to obtain 160 mg of Isomer A and 125 mg of Isomer B.

1. stirringthe reaction mixture was stirred for 45 minutes
2. temperatureAfter cooling down to 5-l0° C
3. stirringthe reaction mixture was stirred for 1 hour
4. extractionExtraction
5. washby washing with a solution of sodium bicarbonate
6. customdrying
7. filtrationfiltering