Ph.D. in Chemistry from IIT Indore, M.Sc Organic Chemist from NIT Warangal
RESEARCH, TEACHING, or OTHER INTERESTS
Chemistry, Organic Chemistry, Catalysis, Medicine
7
Scopus Publications
Scopus Publications
Robust Organocatalytic Three-Component Approach to 1,3-Diarylallylidene Pyrazolones via Consecutive Double Condensation Reactions Ashvani K. Patel, Sampak Samanta Journal of Organic Chemistry, 2024 A robust pyrrolidine-BzOH salt-catalyzed one-pot three-component reaction involving 4-unsubstituted pyrazolones, aryl/heteroarylaldehydes, and aryl methyl ketones is reported for the first time. This catalytic process fortifies an efficient method, allowing for the practical synthesis of a wide array of synthetically useful 1,3-diarylallylidene pyrazolones in good to high yields exclusively in their single geometrical isomer forms. Furthermore, this catalyst facilitates a sequential double condensation reaction under thermal conditions, thereby enabling two consecutive C═C bonds through displacement of aryl groups. Moreover, this organocatalytic technique achieves a 100% carbon atom economy, marking a significant step forward toward efficient and sustainable synthesis.
Organocatalyzed Double C(sp3)−H Alkylation of Cyclic N-Sulfonyl Ketimines with 3-Chloropropiophenones: Selective Access to 2,3,6-Trisubstituted Pyridines Ashvani Kumar Patel, Sampak Samanta European Journal of Organic Chemistry, 2023 An efficient sequential one‐pot, two‐step pseudo‐four‐component reaction between 3/4‐methyl N‐sulfonyl ketimines with 3‐chloropropiophenones triggered by DIPEA/NaHCO3 as a cooperative base and subsequent aza‐cyclization using NH4OAc is reported. This transition‐metal‐oxidant‐free technique concocts new C−C/C=C/C=N−C bonds selectively, guaranteeing acceptable yields of 2,3,6‐trisubstituted pyridines possessing ortho‐hydroxyaryl/benzenesulfonamide and propiophenone moieties at C2 and C3 positions, respectively. Interestingly, while replacing methyl‐substituents with straight alkyl chains of N‐sulfonyl ketimines, only a monoalkylation reaction happened with in situ‐generated vinyl ketones to deliver promising yields of 3‐picoline derivatives. Moreover, the synthetic transmutation of prepared pyridine derivative led to several important classes of pyridocoumarin, 5H‐chromenopyridine, and di(pyridin‐3‐yl) methane derivatives.
AgOTf/Et3N Cooperative Catalysis Enabled One-Pot Access to α-(Indolizinylethyl)-Substituted N-Sulfonyl Ketimines via an Imino-Alkyne Cyclization Rajni Lodhi, Ashvani K. Patel, Sampak Samanta Asian Journal of Organic Chemistry, 2022 Abstract The β‐Csp 3 −H functionalization of N‐sulfonyl ketimines with 2‐(2‐enynl)pyridines/quinolines via a cooperative Ag(I)‐/organobase‐catalyzed 5‐ endo‐dig cyclization‐addition reaction is reported. This successive C−N/C−C bond‐making reaction provides a simple and atom‐economical technique for granting a diverse set of 1,3‐disubstituted indolizines/pyrrolo[1,2‐ a ]quinolines possessing a synthetically resourceful N‐sulfonyl ketimine moiety. Moreover, our designed strategy applies to broad substrates and allows various functionalities. Furthermore, this technique has many imperative synthetic points such as mild reaction conditions, low catalyst loading, acceptable chemical yields and highly diastereoselective (up to ≤93 : 7 dr). The N‐sulfonyl ketimine moiety of indolizine was easily transmuted into the reputed classes of coumarin and benzofuran derivatives.
Reversal Reactivity of β-Alkylnitroalkenes as 1,3-Binucleophiles: Application to Nitroarenes using Organocatalysis Debashis Majee, S Banuprakash Goud, Soumitra Guin, Shikha S. Rathor, Ashvani K. Patel, Sampak Samanta Asian Journal of Organic Chemistry, 2021 Abstract An efficient pyrrolidine : 4‐ClBzOH salt (catalyst IV ) catalyzed [3+3] cyclization reaction of β‐alkyl‐substituted nitroalkenes as 1,3‐binucleophiles with various β‐aryl/alkyl/alkenyl‐substituted acroleins in an open‐atmosphere is reported. Eventually, this tunable organocatalytic reaction creates one C−C and C=C bonds selectively that turns out to have a wide substrate scope, which affords a series of substituted nitroarenes in good to high yields. In addition, several other positive features are associated with this organocatalytic approach such as evading toxic metal‐catalysts, no need for external oxidant and nitrating agent, 100% carbon‐economical, excellent tolerance of functionalities, water as a sole by‐product, circumventing of pre‐functionalized arenes etc. Moreover, a range of important hetero‐and carbocycles such as 2‐arylcarbazole, 2,6‐diphenylindole, 2′‐chloro‐1,1′ : 4′,1′′‐terphenyl and 1 : 1′ : 4′,1′′‐terphenyl were accessed from nitroarenes through our unique methods.
