in this work, a green, simple and highly efficient procedure for the synthesis of bis(indolyl)methanes is described. the condensation of indoles with carbonyl compounds catalyzed by citric acid in water affords bis(indolyl)methanes in high yields and relatively short reaction times. the advantages of this method are using of water as a low cost solvent and efficient recyclability of the catalyst.

In this work, the volatile composition of kale ( Brassica oleracea L. var. acephala) and its variation during germination were monitored during the first 9 days of seedling development by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography/ion trap-mass spectrometry (GC/IT-MS). Differences were found among the materials in the distinct analyzed periods. A total of 6...

The Strecker-type degradation of phenylalanine in the presence of 2-pentanal and phenolic compounds was studied to investigate possible interactions that either promote or inhibit the formation of Strecker aldehydes in food products. Phenylacetaldehyde formation was promoted by 2-pentenal and also by o- and p-diphenols, but not by m-diphenols. This is consequence of the ability of phenolic comp...

In this project various types of carbonyl compounds were efficiently converted to their corresponding 1,3-oxathiolanes  with 2-mercaptoethanol in the presence of catalytic amount of Al-MCM-41 with microwave energy. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, reusability of the catalyst, and easy workup are noteworthy advantages of ...

β-cyclodextrin sulfuric acid as a green lewis acid catalyst has been applied for the preparation of bis(indolyl)methanes, tris(indolyl)methanes and 3,3'-diindolyloxindole derivatives by the condensation of indoles with various carbonyl compounds in aqueous media with high to excellent yields.

A tetra-n-butylammonium (TBA) salt of a γ-Keggin -6-charged germanodecatungstate, [γ-H(2)GeW(10)O(36)](6-) (I), could act as an efficient homogeneous catalyst for Knoevenagel condensation of active methylene compounds with carbonyl compounds.

Starting from unsaturated carbonyl compounds a mild new cascade reaction involving enolboration, rhodium-catalysed hydroformylation and intramolecular aldol addition in a regio- and diastereoselective fashion leads to cyclic compounds containing highly-functionalised quaternary carbon centres.

Metal-free deprotonative functionalization of heteroaromatic compounds was achieved using an organic superbase catalyst; an organosilicon additive such as trimethylsilylpropyne was employed for activating the catalytic cycle of 1,2-addition to carbonyl compounds.

We report one-pot and chemoselective Knoevenagel-type reactions using highly stable amides and lactams as the electrophilic substrates. The method is based on the in situ activation of amide carbonyl with triflic anhydride and a subsequent reaction with carbanions generated in situ from carbonyl compounds. The amide-based method is an alternative to the versatile thioamide-based Eschenmoser sul...