对叔丁基苯甲醛 、
9-amino-7-methylhomocamptothecin 在
吡啶 、
ytterbium(III) triflate 作用下,
以28%的产率得到8-[(4-tert-butylphenyl)methylideneamino]-20-ethyl-20-hydroxy-10-methyl-17-oxa-3,13-diazapentacyclo[11.9.0.02,11.04,9.015,21]docosa-1(22),2,4(9),5,7,10,15(21)-heptaene-14,18-dione