19 research outputs found
An Efficient Multi-component Synthesis of 6-Amino-3-methyl-4-Aryl-2,4- dihydropyrano[2,3-c]Pyrazole-5-carbonitriles
Multi-component reactions are effective in building complex molecules in a single step in a
minimum amount of time and with facile isolation procedures; they have high economy1–7
and thus have become a powerful synthetic strategy in recent years.8–10 The multicomponent
protocols are even more attractive when carried out in aqueous medium. Water
offers several benefits, including control over exothermicity, and the isolation of products
can be carried out by single phase separation technique. Pyranopyrazoles are a biologically
important class of heterocyclic compounds and in particular dihydropyrano[2,3-c]pyrazoles
play an essential role in promoting biological activity and represent an interesting template
in medicinal chemistry. Heterocyclic compounds bearing the 4-H pyran unit have received
much attention in recent years as they constitute important precursors for promising
drugs.11–13 Pyrano[2,3-c]pyrazoles exhibit analgesic,14 anti-cancer,15 anti-microbial and
anti-inflammatory16 activity. Furthermore dihydropyrano[2,3-c]pyrazoles show molluscidal
activity17,18 and are used in a screening kit for Chk 1 kinase inhibitor activity.19,20 They
also find applications as pharmaceutical ingredients and bio-degradable agrochemicals.21–29
Junek and Aigner30 first reported the synthesis of pyrano[2,3-c]pyrazole derivatives from
3-methyl-1-phenylpyrazolin-5-one and tetracyanoethylene in the presence of triethylamine.
Subsequently, a number of synthetic approaches such as the use of triethylamine,31
piperazine,32 piperidine,33 N-methylmorpholine in ethanol,34 microwave irradiation,35,36
solvent-free conditions,37–39 cyclodextrins (CDs),40 different bases in water,41 γ -alumina,42
and l-proline43 have been reported for the synthesis of 6-amino-4-alkyl/aryl-3-methyl-
2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles. Recently, tetraethylammonium bromide
(TEABr) has emerged as mild, water-tolerant, eco-friendly and inexpensive catalyst. To
the best of our knowledge, quaternary ammonium salts, more specifically TEABr, have notbeen used as catalysts for the synthesis of pyrano[2,3-c]pyrazoles, and we decided to investigate
the application of TEABr as a catalyst for the synthesis of a series of pyrazole-fused
pyran derivatives via multi-component reactionsCUSATOrganic Preparations and Procedures International, 45:429–436, 201
A facile strategy for the synthesis of highly substituted imidazole using tetrabutyl ammoniumbromide as catalyst
A simple and facile strategy for the synthesis of highly substituted
imidazoles has been developed by multi-component condensation of 1,2-diketone,
aldehyde, amine, and ammonium acetate in presence of tetrabutyl ammonium
bromide as catalystCochin University Of Science And TechnologyRes Chem Intermed (2012) 38:359–365
DOI 10.1007/s11164-011-0352-
Synthesis of novel 5-substituted isoxazole-3-carboxamide derivatives and cytotoxicity studies on lung cancer cell line
1369-1375A series of novel 5-substituted
isoxazole-3-carboxamide derivatives 6 have
been prepared by coupling of 5-substituted isoxazole-3-carboxylic acids 3 with substituted-3-benzyloxyaniline <b style="mso-bidi-font-weight:
normal">5 using DCC/HOBT as coupling agent. The products 6 have been evaluated for cytotoxicity
on A549 lung cancer cell line and compounds <b style="mso-bidi-font-weight:
normal">6a, 6b, 6e, 6j are<b style="mso-bidi-font-weight:
normal"> found to show moderate proliferative activity and low
cytotoxicity
A facile and single pot strategy for the synthesis of novel naphthyridine derivatives under microwave irradiation conditions using ZnCl2 as catalyst, evaluation of AChE inhibitory activity, and molecular modeling studies
A series of novel naphthyridine derivatives 3
and 4 was prepared from substituted pyridine 2 and ketones
using ZnCl2 as catalyst under microwave irradiation conditions.
All the compounds were evaluated for AChE
inhibitory activity and promising compounds 3d, 3e, 4b,
and 4g was identified. Representative compounds 3d and
3e were found to show insignificant THLE-2 liver cell
viability/toxicity. The binding mode between X-ray crystal
structure of human AChE and compounds was studied
using molecular docking method and fitness scores were
found to be in good correlation with the activity data.CUSATMed Chem Res (2012) 21:1785–1795
DOI 10.1007/s00044-011-9695-