title: A green expedient synthesis of pyridopyrimidine-2-thiones and their antitubercular activity.
abstract: The pseudo four-component domino reactions of N-substituted-4-piperidones, substituted aromatic aldehydes and thiourea in the presence of solid sodium ethoxide under solvent-free conditions afforded pyridopyrimidine-2-thiones in almost quantitative yields by simply grinding for 1-2 min. at ambient temperature. The synthesized compounds were screened for their in vitro activity against Mycobacterium tuberculosis H37Rv. Among them, (E)-6-benzyl-8-(2,4-dichlorobenzylidene)-4-(2,4-dichlorophenyl)-3,4,5,6,7,8-hexahydropyrido[4,3-d]pyrimidine-2(1H)-thione (MIC 2.8 μM) displays the maximum activity, being 2.7 and 1.7 times more active than the first line antitubercular drugs ethambutol and ciprofloxacin, respectively, and less active than rifampicin and isoniazid, by 28 and 7 times, respectively.
authors.affiliation: Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625 021, India.
authors.forename: Stephen Michael
authors.initials: SM
authors.lastname: Rajesh
authors.forename: Raju Suresh
authors.initials: RS
authors.lastname: Kumar
authors.forename: Lawzer Arun
authors.initials: LA
authors.lastname: Libertsen
authors.forename: Subbu
authors.initials: S
authors.lastname: Perumal
authors.forename: Perumal
authors.initials: P
authors.lastname: Yogeeswari
authors.forename: Dharmarajan
authors.initials: D
authors.lastname: Sriram
mesh_terms: D000995:Antitubercular Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D011743:Pyrimidines / Q000737:chemistry*; D013871:Thiones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000995:Antitubercular Agents; D011743:Pyrimidines; D013871:Thiones