Khellin → 1-(6-Hydroxy-4,7-dimethoxy-benzofuranyl)-3-(1-pyrrolidinyl)-2-buten-1-one

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Reaction Steps

A methanolic solution of khellin (5.2 g) and pyrrolidine (2.82 g) is heated at 80° C. for 6 hr. Upon cooling, bright orange crystals precipitate from the reaction mixture. After filtration, there is obtained 6.3 g of pure title product. Silica gel TLC Rf is 0.74 in ethyl acetate. Infrared absorptions are observed at 3180, 3160, 3120, 2300, 1630, 1600, 1530, 1345, 1325, 1260, 1170, 1155, 1140, 1130, 1060, 1050, and 1030 cm-1. NMR absorptions are observed at 7.45, 6.8, 6.25, 4.05, 3.89, 3.22-3.70, 2.68, and 1.8-2.15δ. The mass spectrum exhibits peaks at 331, 300, 261, 220, 205, 177, 111, 110, 83, and 70. The carbon:hydrogen:nitrogen ratio is 65.09:6.32:4.18.

Provenance & Evidence