Synthesis and biological evaluation of pyrimidine analogs of antimycobacterial purines.

Pyrimidine analogs of antimycobacterial 6-aryl-9-benzylpurines have been synthesized and screened for antibacterial activity against Mycobacterium tuberculosis H(37)Rv in vitro. Several active compounds were identified and the best results were observed for 5-formamidopyrimidines. These compounds generally displayed IC(90) values < or =1microg/mL, and they exhibited low toxicity towards mammalian cells. Imidazolylpyrimidines, which may be regarded as fleximer analogs of the parent purines, were also synthesized and one of them was found to be quite a potent inhibitor of M. tuberculosis (IC(90) 14microg/mL).

Synthesis, structure, and antimycobacterial activity of 6-[1(3H)-isobenzofuranylidenemethyl]purines and analogs.

6-Benzofuryl-, styryl, benzyl, and furfurylpurines as well as 6-[1(3H)-isobenzofuranylidenemethyl]purines have been synthesized and their activities against Mycobacterium tuberculosis (Mtb) determined. Several compounds displayed profound antimycobacterial activity in combination with low toxicity towards mammalian cells. NMR and X-ray crystallography were employed to determine the detailed structures and the results were supported by quantum chemical calculations.

Synthesis and antimycobacterial activity of 5-formylaminopyrimidines; analogs of antibacterial purines.

Pyrimidine analogs of antimycobacterial purines have been synthesized and their biological activities evaluated. Several 5-formamidopyrimidines exhibited profound activity against Mycobacterium tuberculosis in vitro (IC(90)< or =1.5 microg/mL), and they were essentially inactive against other bacteria.

Synthesis, biological activity, and SAR of antimycobacterial 2- and 8-substituted 6-(2-furyl)-9-(p-methoxybenzyl)purines.

A number of 6-(2-furyl)-9-(p-methoxybenzyl)purines carrying a variety of substituents in the 2- or 8-position have been synthesized and their ability to inhibit growth of Mycobacterium tuberculosis in vitro has been determined. It is demonstrated that sterical hindrance in the purine 8-position reduces activity and that C-8 should be unsubstituted. In the purine 2-position small, hydrophobic substituents are beneficial. The electronic properties of the 2-substituents appear to have only a minor influence on bioactivity. The compounds studied exhibit low toxicity toward mammalian cells (VERO cells) and are essentially inactive toward Staphylococcus aureus and Escherichia coli. The most active and selective antimycobacterial in the series detected to date is the novel 2-methyl-6-furyl-9-(p-methoxybenzyl)purine with MIC=0.20 microg/mL against M. tuberculosis and IC(50) against VERO cells >62.5 microg/mL. Also the novel 2-fluoro analog and the previously known 2-chloro compound, both with MIC=0.39 microg/mL, are highly interesting drug candidates.

2-Chloro-6-(2-furyl)-9-(4-methoxybenzyl)-9H-purine.

The title compound, C(17)H(13)ClN(4)O(2), displays profound and selective activity against Mycobacterium tuberculosis. In the crystal structure, there are two independent molecules in the asymmetric unit. Intermolecular hydrogen bonding between a CH group of the purine ring and the O atom of the furan ring, and also pi-pi stacking in another direction, builds the three-dimensional network.

Selective anti-tubercular purines: synthesis and chemotherapeutic properties of 6-aryl- and 6-heteroaryl-9-benzylpurines.

6-Aryl- and 6-heteroaryl-9-benzylpurines have been synthesized employing palladium-catalyzed coupling reactions in the step forming the C-C or C-N bond between the aryl- or heteroaryl and the purine. The compounds were screened for activity against Mycobacterium tuberculosis as well as representative Gram+ and Gram- bacteria, and for cytotoxic effects on mammalian cells. Several potent antimycobacterials were identified. These compounds probably act by a novel and selective mechanism; they exhibit low toxicity toward other bacteria as well as mammalian cells.