反应详情

A suspension of 2B —which contained approximately 50% of methyl 5-(4-chlorophenyl)-1,3,4-oxadiazole-2-carboxylate as an impurity—(1.38 g, 2.47 mmol) in dichloromethane (50 mL) was cooled in an ice-bath. Triethylamine (0.51 mL, 3.70 mmol) was added followed by methanesulfonyl chloride (0.27 mL, 3.45 mmol). After the addition, the cooling bath was removed. The mixture was stirred for 7 h. The reaction mixture was transferred to a reparatory funnel and was washed with water followed by aqueous NaHCO3. The organic solution was dried (phase separator) and evaporated. Dichloromethane (50 mL) and diethyl ether (200 mL) were added and the solid product was collected by filtration. The solid was washed twice with diethyl ether and then dried in vacuo. The product was purified using flash column chromatography first eluting with dichloromethane and then with a mixture of dichloromethane and methanol containing 2M NH3 (20:1). There was obtained 0.66 g (75%) of 2C as a solid. 1H NMR (500 MHz, CDCl3): δ 3.13 (s, 3H), 4.43 (dd, 1H), 4.65 (dd, 1H), 4.87 (dd, 1H), 5.12 (dd, 1H), 5.41 (m, 1H), 7.53 (d, 2H), 8.10 (d, 2H), MS (APCI+) m/z 358 [M+H]+.

1. temperaturewas cooled in an ice-bath
2. additionAfter the addition
3. customthe cooling bath was removed
4. customThe reaction mixture was transferred to a reparatory funnel
5. washwas washed with water
6. customThe organic solution was dried (phase separator)
7. customevaporated
8. additionDichloromethane (50 mL) and diethyl ether (200 mL) were added
9. filtrationthe solid product was collected by filtration
10. washThe solid was washed twice with diethyl ether
11. customdried in vacuo
12. customThe product was purified
13. washfirst eluting with dichloromethane
14. additionwith a mixture of dichloromethane and methanol containing 2M NH3 (20:1)