Synthesis of Heterocycles Through Multicomponent Reactions in Water

Substrate-controlled selectivity switch in a three-component reaction: sequential synthesis of spiro-oxazolidinedione-cyclopentenones and hydroxy enaminobarbiturates in water

“…The results show that the reaction is quite general with methyl acetoacetate, ethyl acetoacetate, tert-butyl acetoacetate, and acetylacetone affording 4, but failed to furnish the expected products with 1-phenylbutane-1,3-dione and ethyl 3-oxopentanoate. During further substrate screening, when the substrate combination was switched from N,N 0 -dimethylalloxan to alloxan using the optimized conditions, to our surprise the expected products 4 was not obtained and hydroxy enaminobarbiturates 6 was gained instead as the product (Table 1, entries [20][21][22][23].…”

“…19 Over the last decade multicomponent cascade reactions, particularly those performed in water as a cheap, non-ammable, nontoxic and environmentally friendly solvent, has witnessed considerable growth and development as a powerful tool in organic synthesis because of their expedient building up of molecular complexity and diversity, operational simplicity, convergence, atom economy, bond-forming efficiency and other suitable features from the point of view of green chemistry. 20,21 Fig. 1 Some biologically important oxazolidinedione-and cyclopentane-containing drugs and designed cyclopentenone-fused spiro oxazolidinediones hybrid prototype.…”

Synthesis of Nitrogen- and Oxygen-Containing Heterocycles Catalysed by Metal Nanoparticles Reported in 2022

“…42 Several three-to seven-membered heterocyclic ring systems have been synthesised using MNPs as catalysts, as evident from the published literature from the scientific community. 43 As part of the on-going research endeavour from this laboratory for the synthesis of such heterocyclic scaffolds [44][45][46][47][48][49][50][51] with biological importance, [52][53][54][55] we provided a decennary report on MNP-catalysed synthesis of heterocycles published during 2010-2019, 49 and kept updating the same for 2020 50 and 2021. 45 Herein, we have provided further updates of the review on the metal nanoparticle-catalysed synthesis of aza-and oxa-heterocycles, with a primary focus on the mechanistic insights into MNPs and synthetic approaches to heterocyclic scaffolds, together with their elaborated understandings, reported during the calendar year 2022 (Table 1).…”

Green Preparation and Structure Elucidation of Spiro Indole Derivatives Using Grindstone Technique

“…In this study, we report the development of a solvent-free mechanochemical 31,32 approach for the multicomponent 33,34 synthesis of a series of Spiro indole derivatives in one step by the reaction of isatin, malononitrile and rhodanine using grindstone chemistry technique as shown in Scheme I. The three starting compounds were mixed in a porcelain mortar at room temperature in the presence of few drops of piperidine and ground for 5-10 minutes.…”