Utility of β-diketones in heterocyclic synthesis: Synthesis of new tetrahydro-pyrimidinethione, pyrazole, thiophene, dihydropyridine, dihydropyrane, pyridazine derivatives and investigation of their antimicrobial activity

Synthesis, characterization and in vitro antimicrobial activity of novel fused pyrazolo[3,4-c]pyridazine, pyrazolo[3,4-d]pyrimidine, thieno[3,2-c]pyrazole and pyrazolo[3′,4′:4,5]thieno[2,3-d]pyrimidine derivatives

“…Heterocycles containing a pyrazole or pyrazolone nucleus have been reported to show abroad spectrum of biological activity including antimicrobial [4], anti-cyclooxygenase [5], anti-convulsant [6], antitubercular [7], antitumor [8], anti-inflammatory [9], analgesic [10], antidiabetic [11], antipshycotic [12–14]. In last few years, we have been involved in a program aimed at developing new efficient synthetic approaches for the synthesis of heterocyclic compounds of biological interest [15–17]. Since most of the pyrazole derivatives show anti-microbial activity, the synthesized compounds are also expected to show antimicrobial activity.…”

Microwave assisted the short time clean synthesis of 1,3-diketones as building blocks in heterocyclic synthesis: a facile synthesis and antimicrobial evaluation of new dihydropyridine, 4H-pyrane, dihydropyridazine, pyrimidine and pyrazole derivatives

“…The reactions under microwave irradiation take place in few minutes and no solvent is required [22][23][24][25]. In continution to our research for chemistry developments [26][27][28][29], we report here the use of microwave irradiation for the synthesis of 1-(1-hydroxynaphthalen-2-yl)-3-phenyl-propane-1,3-dione 3 in a quantitative yield (91%) from the reaction of α-naphthol and ethyl benzoylacetate in the presence of zinc chloride [30]. Rather than the expected coumarin 4 as the literature [31].…”

“…Compound 5 readily reacted with cyanothioacetamide 7 as example of active methylene reagents in refluxing ethanolic sodium ethoxide yield the expected pyridinethione derivative 10 which established on its spectral data (IR, 1 H-NMR, mass spectra, 13 C-NMR and elemental analyses). So, its mass spectrum revealed a molecular ion peak at m/z = 384 (M + + 2) corresponding to a molecular formula C 23 H 14 N 2 O 2 S. Formation of pyridinethione 10 is believed to be proceed via initial addition of active methylene moiety in cyanothioacetamide on the π-bond system of the carbonyl group of 5 to afford the Michael adduct 8 that cyclizes by losing water molecule under the same reaction condition to give intermediate 9 which eliminate dimethylamine molecule to yield the final structure 10 as demonstrated in (Scheme 2) [34]. Furthermore, the behavior of enaminone 5 toward binucleophilic reagents was also investigated.…”

Microwave assisted the short time clean synthesis of 1,3-Diketones as Building Blocks in Heterocyclic Synthesis: A Facile Synthesis and Antimicrobial Evaluation of New Dihydropyridine, 4H-Pyrane, Dihydropyridazine, Pyrimidine and Pyrazole derivatives

“…The reactions under microwave irradiation takeplace in few minutes and no solvent is required [22][23][24][25]. In continution to our research for chemistry developments [26][27][28][29], we report here the use of microwave irradiation for the synthesis of 1-(1-hydroxynaphthalen-2-yl)-3phenylpropane-1,3-dione 3 in a quantitative yield (91%) from the reaction of α-naphthol and ethyl benzoylacetate in the presence of zinc chloride [30,33]. Rather than the expected coumarin 4 as literature [31][32].…”