Amidinomycin

The stereoisomers of amidinomycin 7 and their intermediates 1-6, which are produced from homochiral 3-oxocyclopentanecarboxylic acids by asymmetric synthesis, are tested for their antimicrobial effects by agar diffusion test and by Bouillon serial dilution assay. Their antibiotic activities against Bacillus subtilis, Staphylococcus aureus, and Micrococcus Iuteus, respectively, are reported. Structure-activity relationships depend on the type and combination of functional groups, on only the relative stereochemistry as well as on the grade of lipophilia of the tested compounds.

A set of racemic N-phenyl-substituted β-amidoamidines hydrochlorides 4, which are structurally related to natural antiviral agent amidinomycin (1), was synthesized in four steps starting from methacryloyl anilide (5). In the final step of the synthetic route, an uncommon monoacylation of β-aminoamidine 8 at the less reactive β-phenylamino-group took place. To rationalize this result, a mechanism which involves initial acylation at the more active amidine-function followed by intramolecular acyl-group transfer to β-phenylamino-group was suggested. All three β-amidoamidines 4d-f bearing long linear aliphatic chain (from n-C8H17 to n-C12H25) revealed significant in vitro activity against influenza A virus (H3N2) and modest cytotoxicity. The in vitro antiviral potency of 4d,e is 6-20 times greater than that of commercial rimantadine with lower EC50 values and higher therapeutic index. The non-toxic in vivo compounds 4d-f showed a beneficial protective effect in influenza A (H3N2) infected mice.

A family of naturally occurring oligopeptides includes netropsin, distamycin, anthelvencin, kikumycin B, amidinomycin, and norformycin. Netropsin (I) and distamycin (II) express their biological activities by targeting specific sequences of chemical functionalities in the minor groove of DNA. Both netropsin and distamycin can be regarded as polyamide chains in which each alpha-carbon has been replaced by a five-membered pyrrole ring. The repeat distance in such an augmented polyamide chain is almost the same as the distance from one base pair to the next along the floor of a minor groove within beta-DNA. In this paper we report the synthesis of 16-21 cross-linked polyamides containing a thiazole heterocyclic ring bearing the active functionalites NH(2), NHCHO, or H. 16 and 17 were synthesized by DCC and HOBt catalyzed reaction of 5 with 14 and 15, while the formylation products 18 and 19 were obtained by coupling the formylated 4-methyl-thiazolated acid 6 with 14 and 15. The deaminated compounds 20 and 21 were obtained by the coupling of 5-trichloroacetyl-4-methylthiazole 7 synthesized from 4-methylthiazole. All the six cross-linked polyamides 16-21 were tested for their DNA gyrase inhibition. The studies have shown these polyamides have better sequence recognition and a greater percentage of inhibition than the corresponding monomers. The compound 17 shows complete inhibition of gyrase at 0.5 microM concentration as compared to the naturally occurring distamycin at 1.0 microM.