- Application of alkoxy-λ6-sulfanenitriles as strong alkylating reagents
-
Alkoxy-λ6-sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, ptoluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ6-sulfanenitriles showed an opposite trend to the usual SN2 character, i.e. Me (la), Pr (1b), and Bu (1d) ? i-Pr (1c). In the presence of p-TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy-λ6-sulfanenitrile, was found to undergo an SN2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield.
- Hao, Wei,Fujii, Takayoshi,Dong, Tiaoling,Wakai, Youko,Yoshimura, Toshiaki
-
p. 193 - 198
(2007/10/03)
-
- Aqueous high-temperature chemistry of carbo- and heterocycles: Part 24 [1]. First demonstration of specific C-C bond scission of the pyridine ring. Reactions of piperidine, pyridine and some of their methyl derivatives in aqueous formic acid
-
In its reactions with the title compounds, formic acid variously acts as a formylating, methylating, and reducing agent. Both pyridine and piperidine are converted in significant amounts into 1-methyl-, 1-ethyl-, 1-propyl- and 1-pentyl-piperidines. Of the N-alkyl groups, isotopic labeling shows that only N-methyl derives from the formic acid, while the N-ethyl and N-propyl arise from heterocyclic ring C-C bond scission by retro-vinylogous-bis-aza-Aldol reactions. Detailed analysis of the products for pyridine, piperidine, and their 4-methyl derivatives, reacted separately and mixed, supports mechanisms in which a piperidine adds 1,2 to a pyridinium cation, or to a di- or tetra-hydropyridine, to initiate reaction sequences leading to the product slates found.
- Katritzky, Alan R.,Parris, Roslyn L.,Ignatchenko, Elena S.,Balasubramanian, Marudai,Barcock, Richard A.,Siskin, Michael
-
p. 220 - 230
(2007/10/03)
-
- Unprecedented Pyridine Ring C-C Bond Cleavages by Formic Acid.
-
Formic acid at 350 deg C converts pyridine and 4-methylpyridine into products deriving from both αβ and βγ C-C bond cleavages of the pyridine ring.
- Siskin, Michael,Katritzky, Alan R.,Balasubramanian, Marudai,Ferrughelli, David T.,Brons, Glen,Singhal, Gopal H.
-
p. 4739 - 4742
(2007/10/02)
-
- PIPERIDINE-MODIFIED FISCHER-TROPSCH SYNTHESIS
-
N-Alkylpiperidines with alkyl fragment length from C1 to C15 were synthesized by the reaction of CO + H2 + piperidine.The molecular mass distribution of the N-alkylpiperidines has two different distribution parameters α.Thus, α = 0.45 +/- 0.03 for C1-C5 alkyl fragments, while α = 0.65 +/- 0.02 for C6-C15.Piperidine was found to act as modifier reagent and chemical trap for the intermediates in the synthesis reaction.
- Kliger, G. A.,Lesik, O. A.,Mikaya, A. I.,Marchevskaya, E. V.,Zaikin, V. G.,et al.
-
p. 435 - 438
(2007/10/02)
-
- Catalytic Hydroamination of Furfuryl and Tetrahydrofurfuryl Alcohols with Nitriles
-
Reaction of furfuryl and tetrahydrofurfuryl alcohols with nitriles over copper oxide catalysts under a hydrogen pressure of 15 atm at a temperature of 230 deg C gives N-alkylfurfuryl- (yield 46-50percent) and N-alkyltetrahydrofurfurylamines (49-53percent), and N-alkylpiperidines (28-41percent).A reaction mechanism is proposed.
- Kozintsev, S. I.,Basalaeva, L. I.,Gladkikh, L. V.,Kozlov, N. S.
-
-
- Catalyst system for amine transalkylation
-
In the transalkylation of tertiary amines, unexpected higher yields are achieved requiring substantially less catalyst and much shorter reaction times at lower reaction temperatures using a homogeneous catalyst in the presence of an alcohol solvent and carbon monoxide. The process may be exemplified by reacting triethylamine and tripropylamine in the presence of a homogeneous triosmiumdodecacarbonyl catalyst, ethanol, and carbon monoxide to prepare diethylpropylamine and ethyldipropylamine.
- -
-
-
- HYDROGENOLYTIC CLEAVAGE OF PYRIDINE ON DIFFERENT COBALT-MOLYBDENUM AND NICKEL-TUNGSTEN CATALYSTS
-
Composition of the reaction products formed by hydrogenation of pyridine at 300 deg C and 15 MPa in the presence of 15 sulphided and unsulphided molybdenum and tungsten catalysts promoted by cobalt and by nickel, respectively, using alumina as the support in most cases, has been examined.It has been proved that the catalyst composition affects both its hydrogenation activity and the ratio of transalkylation to cracking (or hydrocracking) reactions.Relations between the catalysts composition and its activity and selectivity found for the reaction of pyridine differ from those reported for hydrogenolytic cleavage of thiophene, hydrogenation and isomerisation of cyclohexene.
- Cerny, Mirko,Kraus, Milos
-
p. 1348 - 1354
(2007/10/02)
-
