Mitomycin derivatives as antileukemia agents

Mitomycin compounds represented by the formula:

• ##STR31## wherein A is ON-- or R.sub.4 N.dbd.N-- wherein R.sub.4 is selected from ##STR32## (wherein R.sub.5 and R.sub.8 are each independently selected from hydrogen, alkyl having 1-6 carbon atoms and cycloalkyl having 3-6 carbon atoms;
• R.sub.6 is selected from hydrogen, halogen, hydroxy, alkoxy having 1-6 carbon atoms, amino and nitro;
• R.sub.7 is selected from alkyl having 1-6 carbon atoms and cycloalkyl having 3-6 carbon atoms;
• and X is selected from oxygen, sulphur and imino) and an unsubstituted or substituted heterocyclic group selected from imidazoyl, imidazolinyl, thiazolyl, thiazolinyl, oxazolyl, oxazolinyl, triazolinyl and pyrimidyl (wherein the substituent is selected from alkyl having 1-6 carbon atoms);
• R.sub.1 and R.sub.2 are each independently selected from hydrogen, alkyl having 1-6 carbon atoms, cycloalkyl having 3-6 carbon atoms, unsubstituted or substituted phenethyl, diphenylmethyl, trityl, benzyl, phenyl and naphthyl (wherein the substituent is selected from one or two members selected from halogen, nitro, cyano, alkyl having 1-6 carbon atoms and alkoxy having 1-6 carbon atoms), unsubstituted or substituted alkanoyl having 1-6 carbon atoms and alkanesulfonyl having 1-6 carbon atoms (wherein the substituent is selected from 1, 2 or 3 halogen benzenesulfonyl, p-toluenesulfonyl and benzylsulfonyl;
• R.sub.3 is hydrogen or carbamoyl;
• Y is hydrogen or methyl;
• Z is selected from hydrogen, methyl and acetyl;
• and is an .alpha. or .beta. bond.