abstract |
Cyclic polyamines with N nitrogen atoms in the ring are N-1-protected (eg all but one nitrogen atom are protected) in high yield using certain fluorine-containing agents which provide easy deprotection. Preferably, a novel process for the preparation of 1,1 '- [1,4-phenylenebis (methylene)] - bis-1,4,8,11-tetraazacyclotetradecane is disclosed. |