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Novel 5-ring heterocyclic building blocks are synthesized. These can be incorporated into analogs of peptide antibiotics such as microcin B17, which is a potent DNA-gyrase inhibitor that exhibits eight thiazole and oxazole moieties. In particular, the syntheses of imidazole and bisoxazole amino acids as novel peptidomimetics are reported, this includes a new procedure for the oxidative conversion of the intermediates oxazoline, imidazoline as well as oxazole-oxazoline into the corresponding heteroaromatic compounds. A mixture of 1,8-diazabicyclo-[5.4.0.]-undec-7-ene carbon tetrachloride/acetonitrile and pyridine proved to be a very effective and mild agent.

The antitumor effect of some N alpha-benzyloxycarbonyl-N,N-bis-(2-halogenethyl)hydrazide derivatives of lysine, glycine, cystine, phenylalanine and p-chlorophenylalanine, was studied. Six of eight newly synthesized compounds show considerable antitumor effect on solid Walker carcinosarcoma 256 (about 95% tumor growth inhibition). Three of these compounds under study increased the lifespan of mice with leukemia L1210. The investigation of the effect of N alpha-benzyloxycarbonyl,D,L-phenylalanine-N,N-bis(2-chloroethyl)hydrazine on various mouse tumors showed remarkable growth inhibition of the Ehrlich ascites carcinoma, sarcoma 37, colon adenocarcinoma akatol and lesser antitumor effect also on solid adenocarcinoma 755, Lewis lung carcinoma and melanoma B16. All investigated compounds exhibited depression of leukocyte count--their toxicity being, however, lower than that of sarcolysine in parallel experiments.