Little is known about the chemical reactions involved in the conversion of carbohydrate to fatty acids. Hypothetical schemes have been abundant, and have included aldol condensation of acetaldehyde (Magnus-Levy2"), aldol condensation of acetaldehyde with pyruvic acid (Smedley,30 Smedley and Lubrzynska81), direct condensation of hexoses (Fischer1"), and other possibilities (Hilditch15). The lack...

Carbohydrat,es are fermented by Clostridium acetobutylicum and related microorganisms with the formation of acetic acid, n-butyric acid, acetone, ethanol, and n-butanol. It has been conclusively proved that the butanol arises by the reduction of the butyric acid (1, 2). As yet, however, there is no exact information as to the sequence of reactions by which butyric acid is formed from glucose by...

Direct 2(5H)-furanone annulation produces promising cross-coupling partners incorporating mor p-bromoand p-tosyloxyphenyl groups into the 5-position of a notable 2(5H)furanone pharmacore. The present one-pot annulation method involves two distinctive reactions: (i) a powerful and crossed Ti-direct aldol addition and (ii) an acid-induced characteristic cyclocondensation, leading to 2(5H)-furanon...

The mechanism of formation of coumarin (1) by Perkin reaction from salicylaldehyde was shown to involve exclusively a basecatalyzed intramolecular aldol-type condensation of O-acetyl salicylaldehyde (2) as an obligatory intermediate followed by dehydration. Direct evidence in support of this contention was provided by the formation of coumarin and 3-phenyl coumarin(5) as the sole products in th...

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...