An appropriate one-pot synthesis of 3,4-dihydropyrano[c]chromenes and 6-amino-5-cyano-4-aryl-2-methyl-4H-pyrans with thiourea dioxide as an efficient, reusable organic catalyst in aqueous medium

A Synthetic Approach to Pyrazolopyranopyrimidinones and Pyrazolopyranooxazinones as Antimicrobial Agents

“…A mixture of 2-chloro-5-nitrobenzaldehyde or 2,4dichlorobenzaldehyde (5 mmol), malononitrile (5 mmol), hydrazine monohydrate (5 mmol), and ethyl acetoacetate (5 mmol) in n-butanol (15 ml) containing few drops of piperidine was heated under reflux for 5 h. The separated solid was filtered off, dried, and crystallized from proper solvent to give compounds 1a and 1b, respectively. [2,3-c] [2].…”

“…2-Amino-3-cyano-4-(H)pyran derivatives [1,2] represent a group of heterocycles of special interest due to their biological activities as antimicrobial, antioxidant, antifungal, and antimycobacterial [3][4][5]. Meanwhile, they have been utilized as building block for the synthesis of important heterocycles including pyrazopyranopyrimidines [6], chromenooxazine [7], and pyrrolopyranopyrazole [8].…”

Valorization of the Modified Mono Ammonium Phosphate by Cobalt in the Synthesise of 3,4‐Dihydropyrano[c]chromene Derivatives

“…In general, 3,4‐dihydropyrano[3,2 c]chromenes are accessible through the one‐pot three‐component condensation of an aromatic aldehyde, malononitrile, and 4‐hydroxycoumarin. Several synthesis of these heterocyclic compounds have been reported, using various catalysts like synthetic diammonium hydrogen phosphate (DAHP), Tetrabutylammonium bromide (TBAB), Sodium dodecyl sulfate (SDS), 4‐(dimethylamino) pyridine (DMAP), [ 14 ] poly(N,N′‐dibromo‐N‐ethyl‐benzene‐1,3‐disulfonamide) [PBBS], ionic liquid [DBU][AC], [ 15 ] Silica‐Grafted Ionic Liquids[Sipim]HSO 4, starch solution, thiourea dioxide, poly (ethylene glycol) grafted N,N‐dimethylaminopyridine functionalized dicationic ionic liquid [DMAP‐PEG1000‐DIL][BF 4 ], 1‐Methylimidazolium tricyanomethanide ([HMIM]C(CN) 3 ) and Ru(II) complexes bearing tertiary phosphine ligands . Despite this, these procedures have drawbacks, which imply unsatisfactory yields, extended reaction times and the use of expensive catalysts.…”

Succinimide-N-sulfonic acid as an efficient recyclable catalyst for the synthesis of some fused indolo pyrano pyrimidinone derivatives

“…As part of continuing effort in our laboratory towards the development of environmentally friendly procedures for the synthesis of biologically active heterocyclic molecules [24][25][26], we now describe the synthesis of 5,6-dihydro-2-(2-oxo-2H-chromen-3-yl)-5-phenyl-indolo[2',3':5,6]-pyrano [2,3-d]pyrimidin-4(3H)-one derivatives from the reaction of 2-amino-4,5-dihydro-4-phenylpyrano [3,2-b]indole-3-carbonitriles and coumarine-3-carboxylic acid using SuSA as an efficient reusable catalyst under solvent-free conditions. 2-Amino-4,5-dihydro-4-phenylpyrano [3,2-b]indole-3-carbonitriles were synthesized from benzaldehydes, 3-hydroxyindole and malononitrile using TUD as an efficient organocatalyst (Scheme 1).…”

“…In recent years, TUD is used as the catalyst for the hydrolysis of imines [27], synthesis of naphthopyran derivatives [28], synthesis of a library of novel heterocyclic compounds [29], synthesis of 3,4-dihydropyrimidinones [30] and for the catalytic oxidation of alcohols [31]. We have also reported the application of TUD for the synthesis of 3,4-dihydropyrano[c]chromenes and 6-amino-5-cyano-4-aryl-2-methyl-4H-pyrans in water [26]. Multicomponent reactions (MCRs) allow the creation of several bonds in a single operation and are attracting increasing attention as one of the most powerful emerging synthetic tools for the creation of molecular diversity and complexity [32][33][34].…”