The direct three component modified Mannich reaction via condensation of aldehydes, 2-naphthol or 2,7-naphthalendiol and piperidine to generate Betti bases has been carried out over L-proline (20 mol%) with high efficiency under solvent free conditions at 70 OC. Also, the reaction of aromatic aldehyde and 4-hydroxycoumarin in the presence of L-proline (20 mol%) in the ethanol under reflux condi...

A three-component reaction of beta-nitrostyrene, arylmethylidenemalononitrile and malononitrile catalyzed by imidazole produced the corresponding polysubstituted cyclohexene derivatives in moderate to good yields under mild conditions. A further improvement of this three-component reaction has also been achieved by starting from a commercially available aromatic aldehyde, nitromethane and malon...

Bulky aluminum Lewis acids such as MAD and MABR are introduced as new efficient catalysts in substoichiometric amounts for the allylation of aldehydes with allyltributylstannane. In addition, chemoselective allylation of a less hindered or aromatic aldehyde was achieved with catalytic amounts of the carbonyl receptor aluminum tris(2,6-diphenyl-phenoxide) (ATPH).

A concise and efficient approach to the synthesis of structurally diverse 6,8a-dihydropyrido[2,3-d]pyrimidine derivatives has been accomplished by a three-component reaction involving sulfonyl acetonitrile, an aromatic aldehyde, and 6-aminouracil. The method involves the domino Knoevenagel condensation/Michael addition/cyclization cascade in the presence of triethylamine in refluxing ethanol.

The first enantioselective synthesis of the fungal metabolite (+)-O-methylasparvenone was achieved in eight steps and 22% overall yield from inexpensive 3,4,5-trimethoxybenzaldehyde dimethyl acetal. Key steps include (i) early-stage asymmetric alkynylation of an aromatic aldehyde with a propiolate, (ii) intramolecular Friedel-Crafts acylation, and (iii) site-selective cleavage of an aryl methyl...

In the crystal structures of the respective title compounds, C12H10N4O, C13H11N3O.H2O and C11H9N3O2, variations in the torsion angles of the aromatic pyridyl and benzoyl groups are observed, and the disposition of the heterocyclic aldehyde is shown to be influenced by the ring size of this group.

An efficient four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles is described by one-step condensation of an aldehyde, benzil, ammonium acetate and primary aromatic amine with nanocrystalline magnesium aluminate in ethanol under ultrasonic irradiation. High yields, short reaction times, mild conditions, simplicity of operation and easy work-up are some advantages of this protocol.

The title compound, C(14)H(11)BrClNO, is a Schiff base compound derived from the condensation of 3-bromo-5-chloro-salicyl-aldehyde and o-toluidine in methanol. The aromatic rings make a dihedral angle of 38.3 (1)°. The mol-ecular conformation is stabilized by an intra-molecular O-H⋯N hydrogen bond, generating an S(6) ring.

A simple and environmentally benign procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes by a one-pot condensation of 2-naphthol with aromatic aldehyde in the presence of [Et3NH][HSO4] as an acidic ionic liquid catalyst under solvent-free conditions has been developed. The reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused s...