N1, N4-bis (tert-butoxycarbony1) spermidine (12) and guanidine reagent N, N'-bis (tert- butoxycarbony1)-S-methylisothiourea (18). The sensitive alkanolamide moiety of (f)-15- deoxyspergualin ((2-11 in 2b) is formed and then protected as its tert-butyldimethylsilyl ether in 21. The reactive ester group of 21 undergoes aminolysis with 12 to form protected deoxyspergualin 22. All of the protecting groups in 22 are removed by trifluoroacetic acid ...
