meso-Functionalized dipyrromethanes 6-10 were synthesized by acid-catalyzed addition of pyrrole to αposition of 2-alkenyl pyrroles. The regiochemistry of the reaction can be explained by either the formation of more stable carbocation intermediate or β-addition of α,β-unsaturated carbonyl compounds. The starting 2alkenyl pyrroles were synthesized by Aldol condensation of 2-formylpyrrole with ac...

The mechansim of the three-component Biginelli dihydropyrimidine synthesis was reinvestigated using (1)H and (13)C NMR spectroscopy. Condensation of benzaldehyde, ethyl acetoacetate, and urea (or N-methylurea) in CD(3)OH according to the procedure described by Biginelli produced the expected 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxylates. According to NMR measurements, ther...

A short and robust approach for the synthesis of 2-(hetero)aryl substituted thieno[2,3-b]indoles from easily available 1-alkylisatins and acetylated (hetero)arenes has been advanced. The two-step procedure includes the "aldol-crotonic" type of condensation of the starting materials, followed by treatment of the intermediate 3-(2-oxo-2-(hetero)arylethylidene)indolin-2-ones with Lawesson's reagen...

A novel one step regioand stereoselective synthesis of functionalised bicyclo[2.2.2]octenones from readily available aromatic precursors is described. The methodology involved in situ generation of reactive spiroepoxycyclohexadienones and p4sþp2s cycloaddition with methyl vinyl ketone. Study on p-facial alkylation that led to the formation of homobrendane derivatives as a result of stereochemic...

Aldol condensation reaction between 3-indolaldehyde 1 and 4-methoxyacetophenone 2 afforded chalcone compounds 3. This compound was reacted with some different reagents such as hydrazine hydrate, phenyl hydrazine, thiosemicarbazide, hydroxylamine, ethyl cyanoacetate, urea and thiourea to give pyrazolines 4a, 4b, 5a, 5b, 6, oxazoline 7, Michael adduct 8, pyranone 9, and oxo 14a and thiopyrimidine...

Chemical investigation of a Fijian ascidian, Polyandrocarpa sp., has resulted in the isolation of two new 2-aminoimidazolone-derived compounds, polyandrocarpamines A (1) and B (2). The structures of these unique metabolites were determined by the interpretation of spectroscopic data and confirmed by total synthesis. The stereospecific synthesis of 1 was accomplished using aldol condensation che...

o-Fructose 1,6-bis(phosphate) aldolase from rabbit muscle (RAMA, 8.C.4.L.2.13) catalyzes the aldol condensation betwe.tr dihyd.oxyacetone phosphate (DHAP) and various aldehydes; the products are ketosugars with 3(S),4iR) stereochemistry. When racemic a-hydroxy aldehydes are condensed with DHAF, two diastereomeric products are formed. This paper demonstrates that RAMA can kinetically resolve a-h...

Microwave assisted new aldol condensation reaction of 1-oxo-1,2,3,4tetrahydrocarbazoles 1 with thiophene-2-carbaldehyde 2 in the presence of alcoholic KOH affords a single product 2-Thiophen-2-ylmethylene-2,3,4,9-tetrahydro-carbazol-1-one 3. 3 on irradiation with hydroxylamine hydrochloride yielded 3-Thiophen-2-yl-4,5-dihydro-10H-2-oxa-1,10-diazacyclopenta[a]carbazole 4 and 3 on irradiation wit...

Acid-base bifunctional organic polymeric catalysts were synthesized with tunable structures. we demonstrated two synthesis approaches for structural fine-tune. In the first case, the framework flexibility was tuned by changing the ratio of rigid blocks to flexible blocks within the polymer framework. In the second case, we precisely adjusted the acid-base distance by distributing basic monomers...

Traditionally, bio-butanol is produced with the ABE (Acetone Butanol Ethanol) process using Clostridium species to ferment sugars from biomass. However, the route is associated with some disadvantages such as low butanol yield and by-product formation (acetone and ethanol). On the other hand, butanol can be directly produced from ethanol through aldol condensation over metal oxides/ hydroxyapat...