ABSTRACT. Starting from 2-acetylbenzofuran derivatives 1a-d, methyl/ethyl 4-substituted/unsubstituted benzofuran-2-yl)-2,4-dioxobutanoate 2a-d and 3a-d have been synthesized by Claisen's condensation reaction with diethyloxalate. The transesterified product, 1,3-diketoester 2a-d on condensation with phenyl hydrazine undergo cyclization to afford the corresponding methyl 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carboxylate 4a-d, which upon further condensation with hydrazine hydrate yielded 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide 5a-d. The structures of the newly synthesized compounds 2a-d, 3a-d, 4a-d and 5a-d were characterized by their elemental analysis and spectral studies such as IR, 1 H NMR, 13 C NMR and MS. All the synthesized compounds were screened for their antimicrobial activity. Most of the synthesized compounds showed high sensitivity against the selected bacteria and fungi at various concentrations.
The synthesis of polysubstituted quinoline and its derivatives is the focus of a large number of pharmacological studies because of their wide range of biological applications. The quinoline moiety constitutes the main framework of several natural products such as Montelukast and Skimmianine. Quinoline was synthesized by Vilsmeier-Haack reagent which is a versatile reagent used in various synthetic transformation [1]. Quinine, amodiaquine, piperaquine, orimaquine, mefloquine and chloroquine are used as antimalarial drugs mainly consist quinoline moiety [2]. Quinoline nucleus shows good antitumor [3] and antifungal [4] activities. It is also reported that coordination polymer of quinoline ligand too showed antimicrobial activity [5]. Antimicrobial screening and molecular docking studies of some triazoloquinazolinone [6] has also been studied. On the other hand, thiazolidinones are also an important class of heterocyclic compounds which has been classified as 2,4,5thiazolidinones depending on the position of carbonyl group. Out of these 4-thiazolidinone is a five member ring with carbonyl
An expeditious synthesis of series of novel 1,3,5-thiadiazine (5a-f) and (6a-f) derivatives have been
described. These compounds were synthesized by reaction of 1-(N-((6-methyl-2-(p-tolyloxy)quinoline-
3-yl)methylene)carbamimidoyl)-3-arylthiourea (3a-b) derivatives with N-aryl isocyanodichloride (4a-c)
in chloroform followed by basification with dilute NH4OH to give the target compounds 5a-f; which
were acetylated further to afford six novel 1,3,5-thiadiazin-3-(6H)-yl)ethanone (6a-f) derivatives. Synthesis
of intermediate compounds 3a-b was obtained by reacting 6-methyl-2-(p-tolyloxy)quinoline-3-
carbaldehyde (2a) and 1-carbamimidoyl-3-aryllthiourea (1a-b) in chloroform. Structures of compounds
5a-f and 6a-f were established by FTIR, 1H & 13C NMR, mass spectra and further supported by elemental
analysis. All synthesized compounds were investigated for their in vitro antimicrobial screening against
a panel of pathogenic microorganism comprising S. aureus as Gram positive while E. coli, P. vulgaris, S.
typhi as Gram-negative bacterial strains.
In the undertaken research we have reported simple efficient technique to afford a novel series of 3-(5-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-3-yl)-N-aryl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-6-amine (4a-g) derivatives obtained by one pot cyclocondensation reaction of 5-(5-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-3-yl)-4-amino-4H-1,2,4-triazole-3-thiol (3) with substituted aryl isothiocyanate in DMF and K2CO3, without formation undesirable side products by simple work up procedure. The structures yielded (4a-g) were established by 13CNMR, IR, 1HNMR, elemental analysis and mass spectra. Entire synthesised compounds were screened for their in-vitro biological assay via microorganism Gram positive and Gram negative bacterial strains at different concentrations. The bioassay revealed that some of the compounds have promising antimicrobial activities when compared with standard drug Chloramphenicol.
In present chapter we have reported green and highly efficient method for synthesize novel series of substituted -1H-indazol-3-amine derivative (3a-h) by cyclocondensation reaction of substituted benzonitrile (1a-h) and substituted Hydrazine (2a-h) using ceric (IV) ammonium nitrate (CAN) as a catalyst, EtOH-H2O as a ecofriendly media and reaction was carried out under ultrasound irradiation green method. The structures of newly synthesized indazole derivative (3a-h) were corroborated through spectral investigation such as elemental analysis and spectral studies like IR, C13 NMR, Mass spectra and 1H NMR. The compounds were assessed for their in-vitro antimicrobial activity with pathogenic microbe comprising Gram positive bacterial strains, S. aureus and Gram negative strains E.coli, P.vulgaris, and S. typhi at different concentration. The consequence of bioassay is compared with standard drug Chloramphenicol.
A series of 5-(benzofuran-2-yl)-N-(3-chloro-4-(2-(p-tolyloxy) substituted quinolin-3-yl)-2-oxoazetidin-1-yl)-1-phenyl-1H-pyrazole-3-carboxamide derivatives (4a-f) were synthesized with excellent yields by cyclocondensation reaction of 5-(benzofuran-2-yl)-N′-(2-(p-tolyloxy) substituted quinolin-3-yl)methylene)-1-phenyl-1H-pyrazole-3-carbohydrazide (3a-f) with chloroacetyl chloride in presence of triethylamine in DMF. One pot condensation of 5-(benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide (1) with 2-(p-tolyloxy) substituted quinoline-3-carbaldehyde (2a-f) in ethanol solvent in presence of catalytic amount of acetic acid gave intermediate compounds (3a-f). The structures of newly synthesized compounds have been substantiated through elemental analysis and spectral studies viz. 1H NMR, 13C NMR, IR and mass spectra. All the synthesized compounds were screened for their in vitro antibacterial activity against pathogenic bacteria such as S. aureus and E. coli at different
concentrations.
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