Formic Acid → Camptothecin

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of 9-hydroxycamptothecin (9-HC; 300 mg, 0.82 mmol) in N,N-dimethylformamide (15 ml), triethylamine (0.68 ml, 4.92 mmol. 6.0 eq.) and N-phenyl trifluoromethanesulfonimide (879 mg, 2.46 mmol, 3.0 eq.) were added, and the mixture was stirred at 60° C. for 0.5 hr under argon gas atmosphere. After confirmation of the disappearance of the starting material by thin layer chromatography (chloroform:methanol=20:1), this reaction solution was added with triethylamine (1.14 ml, 8.20 mmol. 10.0 eq.), dichlorobis(triphenylphosphine)palladium (58 mg, 0.08 mmol, 10 mol %), formic acid (189 mg, 4.10 mmol, 5.0 eq.) and heated at 60° C. for 3 hr. After the disappearance of 9-OTfC was confirmed by thin layer chromatography (chloroform:methanol=50:1), and the reaction mixture was cooled, followed by evaporation of the solvent under reduced pressure. The residue was added with chloroform (5 ml) and n-hexane (200 ml) and the resulting precipitate was taken by suction filtration to give camptothecin (CPT) (209 mg, yield 73%) as a yellow solid.

Herkunft & Nachweise