Synthesis of hexopyranosyl acetates and 2,3-disubstituted tetrahydropyrans via chemoselective hydrogenation of hex-2-enopyranosyl acetates

A simple and easy method for chemoselective synthesis of hexopyranosyl acetates and 2,3-disubstituted tetrahydropyrans from hex-2-enopyranosyl acetates was demonstrated. The former was achieved by hydrogenation catalyzed by Rh/Al₂O₃ in EtOAc/toluene solvent at 0 °C, while the latter was carried out using Pd/C in EtOH/AcOH at 25 °C.     

Preparation and polymerization of some N-(dialkylaminoalkyl)acrylamides

A series of N-(dialkylaminoalkyl)acrylamides was synthesized by reductive amination of N-(1,1-dimethyl-3-oxobutyl)acrylamide (diacetone acrylamide) and by the reaction of either an alkenylamine or an amino alcohol with acrylonitrile. These monomers homopolymerize and copolymerize readily to form high molecular weight products. The solubility of the monomers and their homopolymers in water ranges from soluble to insoluble at room temperature. The insoluble materials can be quaternized readily to produce water-soluble products. The solubility of the homopolymers in water decreases with increasing temperature. Glass transition and decomposition temperatures of the homopolymers are reported.     

Reactions of N- and C-alkenylanilines: X. Synthesis of 2-vinyldihydroindoles from 4-methyl-2-(pent-3-en-2-yl)aniline

2-(1-Iodoethyl)-3,5-dimethyl-1-(4-methylphenylsulfonyl)-2,3-dihydro-1H-indole reacted with pyridine, piperidine, N-alkylpiperidines, and dimethylformamide to give dehydrohalogenation and halogen substitution products whose ratio depended on the reagent structure. Heating of 2-(1-iodoethyl)-3,5-dimethyl-1-methylsulfonyl-2,3-dihydro-1H-indole with piperidine resulted in the formation of only dehydroiodination products.     

Reactions of N-(2,2-Dichloro-2-phenylethylidene)arenesulfonamides with Aromatic and Heterocyclic Compounds

Benzene, toluene, and 2-chlorothiophene regioselectively react with N-(2,2-dichloro-2-phenyl- ethylidene)arenesulfonamides in the presence of oleum to give N-[1-aryl(or hetaryl)-2,2-dichloro-2-phenylethyl]arenesulfonamides. Analogous C-amidoalkylation products are formed by the action of N-(2,2-dichloro- 1-hydroxy-2-phenylethyl)- and N-(1-arylsulfonylamino-2,2-dichloro-2-phenylethyl)arenesulfonamides on toluene and 2-chlorothiophene in concentrated sulfuric acid.     

Poly[N-(2-aminoethyl)acrylamido] triethylammonium polyhalide derivatives: Preparation and synthetic applications

Poly[N-(2-aminoethyl)acrylamido]triethylammonium dichloroiodate, tetrachloroiodate, and dibromoiodate polyhalides were developed as a new class of solid phase organic reagents. N,N′-methylenebisacrylamide crosslinked polyacrylamide support was utilized to prepare the reagents. The utility of polyhalide reagents for the α-halogenation of carbonyl compounds and oxidation of alcohols at various reaction conditions is described. The reactivity of the polyhalide reagents increased considerably in polar solvents and the optimum temperature for conducting the reactions was 30°C. Studies on halogenation and oxidation reactions using differently crosslinked polyacrylamide-based polyhalide reagents revealed that the reactivity increased up to 10% crosslinking and decreased progressively on further increase in the degree of crosslinking. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1413–1421, 1997     

Homogenous and heterogenous catalytic hydrogenation and isomerization of hex-1-ene by palladium(II) Schiff base complexes

Summary Pd^II complexes of Schiff bases with N₂O₂ donor sets were tested for their catalytic activity towards the reductive hydrogenation of hex-1-ene. During the hydrogenation, trans- and cis-hex-2-ene isomers were formed which generally react more slowly than hex-1-ene, hence the rate of hydrogenation tends to slow down with increasing conversion. The rates of hydrogenation and isomerization were studied in relation to the catalyst structure, time, type of catalysis and amount and nature of solvents. The solubility of H₂ and the polarity of reaction medium play a significant role in the hydrogenation yield and selectivity. Hydrogenation and isomerization are parallel reactions; a mechanism for the isomerization is proposed.     

Cyclodehydration of N-(2-nitroaryl)-1,2,3,4-tetrahydroisoquinoline derivatives

Compounds 1a-1g gave the corresponding N-oxide derivatives 3a-3g when heated with acetic or propionic acid.     

Asymmetric hydrogenation catalyzed by rhodium complexes of 2,3-bis(dimenthylphosphino)maleic anhydride and 2,3-bis(dimenthylphosphino)-N-phenylmaleimide

2,3-Bis(dimenthylphosphino)maleic anhydride and the phenylimide derivative have been prepared from 2,3-dichloromaleic anhydride and 2,3-dichloro-N-phenylmaleimide, respectively, and dimenthyl(trimethylsilyl)phosphine. These compounds have been used as ligands for Rh complexes and have been tested in the asymmetric hydrogenation of α-acetamidocinnamic acid, methyl-α-acetamidocinnamate and itaconic acid. Optical yields of up to approximately 70% were obtained with α-acetamidocinnamic acid.     

Heterocyclic analogs of pleiadiene. 49. Mass spectra of some N-substituted perimidines and 2,3-dihydroperimidines

The mass spectra of nine compounds of the perimidine series, as well as 1,3-dimethyl derivatives of 2,3-dihydroperimidine, perimidone, and thioperimidone, were obtained and are discussed. The perimidines are distinguished by their high resistance to electron impact. The initial fragmentation of their molecular ions is characterized by detachment of the substituent attached to nitrogen, as well as by detachment of a hydrogen atom from the N-methyl group. It is proposed that the intensities of the doubly charged M²⁺ ions be used to estimate the -donor properties of heterocyclic compounds.See [1] for communication 48.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 684–690, May, 1980.     

Au-catalyzed synthesis of 5,6-dihydro-8H-indolizin-7-ones from N-(pent-2-en-4-ynyl)-beta-lactams

Au-catalyzed synthesis of 5,6-dihydro-8H-indolizin-7-ones from readily available N-(pent-2-en-4-ynyl)-beta-lactams is developed. In this reaction, a 5-exo-dig cyclization of the beta-lactam nitrogen to the Au-activated C-C triple bond is followed by heterolytic fragmentation of the amide bond, forming a highly nucleophilic acyl cation. An expedient formal synthesis of indolizidine 167B was easily achieved using this new method.