Phosphorus--nitrogen compounds XXIII: Oncolytic phosphorylated imines

A series of 15 amidine, iminopiperidine, iso(thio)urea, and guanidine derivatives and six 2,5-dihydro-1,3,5,2-triazaphosphorines were synthesized. Most of the compounds were tested for ability to react with L-cysteine and for antitumor activity against sarcoma 180 and P-388 murine tumor systems. Three acyclic phosphorylated imines and one triazaphosphorine showed activity in the former model to indicate that the P(O)N = C grouping serves as an oncolytic moiety. All agents condensed with L-cysteine with the active antitumor compounds displaying a tendency for relatively higher reactivity with this amino acid.