R. Srinivasa Rao

First examples of C-arylation of aziridines catalyzed by indium triflate

Abstract Aziridines react smoothly with arenes in the presence of a catalytic amount of indium triflate at ambient temperature to afford the corresponding β-aryl amine derivatives in excellent yields with high regioselectivity.

Aza-Diels-Alder reactions in ionic liquids: a facile synthesis of pyrano- and furanoquinolines

Room temperature ionic liquids are found to catalyze efficiently the three component-coupling reactions of aldehydes, amines and cyclic enol ethers such as 3,4-dihydro-2H-pyran and 2,3-dihydrofuran under mild and convenient conditions to afford the corresponding pyrano- and furanoquinolines in excellent yields with high endo-selectivity. Interestingly, 2,3-dihydrofuran afforded selectively endo-products under the similar reaction conditions.

InCl3-Catalyzed hetero-Diels–Alder reaction: an expeditious synthesis of pyranoquinolines

Indium trichloride catalyzes efficiently the cycloaddition reactions of aryl amines with 3,4-dihydro-2H-pyran (DHP) under mild reaction conditions to afford the corresponding pyrano[3,2-c]quinolines in high yields with high diastereoselectivity.

Zinc-mediated acylation and sulfonation of pyrrole and its derivatives

Abstract Pyrrole and its derivatives react smoothly with acid chlorides and sulfonyl chlorides in the presence of zinc metal in toluene at ambient temperature to afford the corresponding 2-acetyl and 2-sulfonyl pyrrole derivatives in high yields with high regioselectivity.

Synthesis of new cis-fused tetrahydrochromeno[4,3-b]quinolines and their antiproliferative activity studies against MDA-MB-231 and MCF-7 breast cancer cell lines

New cis-fused tetrahydrochromeno[4,3-b]quinolines have been synthesized by intramolecular [4+2] imino-Diels-Alder reactions of 2-azadienes derived in situ from aromatic amines and 7-O-prenyl derivatives of 8-formyl-2,3-disubstituted chromenones in the presence of 20mol% Yb(OTf)(3) in acetonitrile under reflux conditions in good to excellent yields. The structures were established by spectroscopic data and further confirmed by X-ray diffraction analysis. These compounds were evaluated for their antiproliferative activity against MDA-MB-231 and MCF-7 breast cancer cells. The results showed that compounds 3e, 3f, and 3k exhibit significant antiproliferative activity against MCF-7 breast cancer cells and low inhibitory activity against MDA-MB-231 breast cancer cell lines. Compound 3h displayed activity as comparable to tamoxifen on both the cell lines.

Solvent free synthesis of 1,5-disubstituted tetrazoles derived from Baylis Hillman acetates as potential TNF-α inhibitors

Solvent free multicomponent reaction of Baylis Hillman acetate, TMS azide and arylnitrile to produce 1,5-disubstituted tetrazole is described. Some of these tetrazoles are found to be potential TNF-alpha inhibitors.

Synthesis of new chromeno-annulated cis-fused pyrano[3,4-c]pyran derivatives via domino Knoevenagel–hetero-Diels–Alder reactions and their biological evaluation towards antiproliferative activity

A new series of chromeno-annulated cis-fused pyrano[3,4-c]pyran derivatives have been synthesized by intramolecular [4 + 2] domino Knoevenagel–hetero-Diels–Alder reactions of 1-oxa-1,3-butadienes derived in situ from 1,3-dicarbonyls/active methylenes and 7-O-prenyl derivatives of 8-formyl-2,3-disubstituted chromenones in the presence of 20 mol% ethylenediamine diacetate (EDDA) in acetonitrile under reflux conditions in good to excellent yields. The structures were established based on spectroscopic data, and were further confirmed by X-ray diffraction analysis. These compounds were evaluated for their anti-proliferative activity using an in vitro MTT cytotoxicity assay. The results clearly demonstrated that compounds 4a, 4b, 4c, 4j, 4k, 4l, 4m and 4n exhibited significant anti-proliferative activity against human A549 lung cancer and non-cancer MRC-5 cell lines along with potent inhibitory activity against human neuroblastoma SK-N-SH cancer cell lines. Among these, compounds 4a, 4b and 4j displayed the most potent anti-proliferative activity against human lung cancer A549 cell lines, while 4a and 4b displayed against neuroblastoma SK-N-SH cancer cell lines when compared to the standard doxorubicin.

Efficient protocol for reductive amination of aldehydes and ketones with sodium borohydride in an ionic liquid/H2O system

Abstract The imines were generated in situ from carbonyl compounds and amines, which undergo smooth reduction with sodium borohydride in an ionic liquid/H2O solvent system. The reaction conditions were very mild and neutral to afford the corresponding highly functionalized amines in excellent yields. IICT Communication No. 041013.

Indium Catalyzed Synthesis of Heterocycles via Cycloadditions

Cycloaddition reactions have found many important synthetic applications in the preparation of biologically important classes of heterocycles. Cycloaddition reactions lead to the formation of new σ-bonds via a cyclic transition state resulting in cyclic products with desired ring size and stereoselectivities. This review collects the synthesis of the most important heterocyclic compounds via cycloadditions under indium catalysis. This review also discusses the mechanistic and stereochemical aspects of these cycloadditions.

Phosphomolybdic Acid (PMA) Catalyzed Highly Efficient and Rapid Synthesis of β-Enaminones

Abstract β-Enamino derivatives have been synthesized by the condensation of amines and β-dicarbonyl compounds in the presence of 1 mol% of phosphomolybdic acid (PMA) at room temperature in good to excellent yields. GRAPHICAL ABSTRACT