Antimycobacterial pyrroles: synthesis, anti-Mycobacterium tuberculosis activity and QSAR studies Original Research Article

A number of known antifungal pyrrole derivatives and some newly synthesized compounds (5–33) were tested in vitro against Mycobacterium tuberculosis CIP 103471. The majority of tested compounds were efficient antimycobacterial agents showing MIC values ranging from 0.5 to 32 μg/mL. A 3-D-QSAR study has been performed on these pyrrole derivatives to correlate their chemical structures with their observed inhibiting activity against M. tuberculosis. Due to the absence of information on a putative receptor responsible for this activity, classical quantitative structure–activity relationships (QSAR) and comparative molecular field analysis (CoMFA) have been applied. A model able to well correlate the antimycobacterial activity with the chemical structures of pyrrole derivatives 5–33 has been developed which is potentially helpful in the design of novel and more potent antituberculosis agents. The combination of CoMFA with classical QSAR descriptors led to a better hybrid 3-D-QSAR model, that successfully explains the structure–activity relationships (r2=0.86) of the training set. A comparison between the QSAR, CoMFA and mixed QSAR–CoMFA models is also presented. The hybrid model is to be preferred, however, because of its lowest values of the average absolute error of prediction toward a limited external test set.