-a simple, efficient, and general method has been developed for the chemoselective acetalization of aldehydes with 1,3-propanediol, 1,2-ethanediol and trimethyl orthoformate in the presence of solid lithium perchlorate under solvent-free conditions. both cyclic and acyclic acetals of aldehydes were obtained under environmentally benign conditions in good to excellent yields.

nano silica-h2so4 is an efficient and mild catalysis system for the regeneration of aldehyde from aldoximes. ketoximes are converted to amides by beckmann rearrangement in the presence of nano silica-h2so4. the reactions are carried out in solvent-free conditions under microwave irradiation (600 w) within 50-120 sec in good yields.

in this research, different alcohols and phenols are subjected to the reaction with hmds in the presence of ionic liquid and silica-supported catalysts. silylation was accomplished under mild reaction conditions at room temperature in short reaction times and good to excellent yields.

a new efficient method for the synthesis of carboacyclic nucleosides as biologically interesting compounds via aza-conjugate addition of pyrimidine nucleobases to a,β-unsaturated esters in the presence of catalytic amount of lioh.h2o (1.2-4.8 mol%) under microwave irradiation is described. this method affords the title compounds in good to excellent yields and in short reaction times.

Chiral N-heterocyclic carbenes were found to be efficient catalysts for the formal [2+2] cycloaddition reaction of alkyl(aryl)ketenes and nitroso compounds to give the corresponding 1,2-oxazetidin-3-ones in moderate to good yields with high enantioselectivities. Reductive ring-opening of the oxazetidinones give the corresponding α-hydroxy acid derivatives in good yields.

Benzylcyanide and 4-nitrobenzylcyanide condensed with triethyl orthoformate and piperidine or morpholine to yield 2-aryl-2-piperidinyl or 2-morpholinylacrylonitriles. These coupled with aromatic diazonium salts to yield the 2-arylhydrazno-2-arylethane nitriles in good yields. The latter were converted into 4-aminopyrazoles in good yields using the Thorpe-Ziegler cyclization.

Benzylcyanide and 4-nitrobenzylcyanide condensed with triethyl orthoformate and piperidine or morpholine to yield 2-aryl-2-piperidinyl or 2-morpholinylacrylonitriles. These coupled with aromatic diazonium salts to yield the 2-arylhydrazno-2-arylethane nitriles in good yields. The latter were converted into 4-aminopyrazoles in good yields using the Thorpe-Ziegler cyclization.

Methoxymethylation of a variety of alcohols was performed using formaldehyde dimethyl acetal in the presence of 1,3-dichloro-5,5-dimethyl hydantoin [DCDMH] and Poly N,N′-dibromo-N-ethyl naphthyl-2,7-disulfonamide [PBNS] as catalysts at room temperature and under solvent-free conditions. Our experiments show that primary and secondary alcohols can be smoothly converted into the corresponding MOM...

Various sulfonamides have been synthesized from triazenes and sulfur dioxide. In the presence of just a catalytic amount of BF3·OEt2, a series of 1-aryl-triazenes were converted into sulfonyl hydrazines in good to excellent yields. When using CuCl2 as the catalyst, the corresponding sulfonamides can be produced from the 1-aryl triazenes in good yields.

Homopropargylic alcohols undergo directed hydrozirconation with Schwartz reagent (Cp(2)ZrHCl) to generate vinyl-metal species in which the metal fragment is proximal to the alkoxide. Electrophilic trapping yields tri-substituted olefins in good yields with good control of regio- and stereochemistry. Experiments with a homopropargylic ether confirmed the role of the hydroxyl group in the directe...