Covalent adducts from 1,3-disubstituted pyridinium salts and piperidine
作者:F. Micheletti Moracci、B. Di Rienzo、S. Tortorella、F. Liberators
DOI:10.1016/s0040-4020(01)93695-6
日期:1980.1
isolated from the reactionbetween piperidine and pyridiniumsalts 1a-f. 3a-f are stable both in the solid state and in apolar solvents, whereas their fast dissociation back to piperidine and pyridinium ions occurs in aqueous solution. The latter, in the alkaline environment produced by the amine, yields the correspondent pseudobases, which are key intermediates of the subsequent reactions. For instance
1-(2-Indolyl)vinylstannane 1b has been transmetallated into both the corresponding HO mixed cyanocuprate and the Cu-catalysed organomagnesium reagent, and the reactivity of these species towards N-alkyl-3-acylpyridinium salts 8 and 17 has been tested.
Synthesis of 3,5-diacyl-4-phenyl-1,4-dihydropyridines
作者:M.-Lluïsa Bennasar、Cecília Juan、Joan Bosch
DOI:10.1016/s0040-4039(98)02084-x
日期:1998.12
via a regio- and chemoselective addition of Ph2Cu(CN)Li2 to β-substituted N-alkylpyridinium salts, followed by acylation of the intermediate 1,4-dihydropyridines with trichloroacetic anhydride and subsequent haloform-type reaction. A similar sequence using an N-silylpyridinium salt and PhMgBr allows the preparation of the corresponding N-unsubstituted dihydropyridines.
Addition of organocopper reagents to N-alkylpyridinium salts. A flexible access to polysubstituted dihydropyridines
作者:M.-Lluı̈sa Bennasar、Cecı́lia Juan、Joan Bosch
DOI:10.1016/s0040-4039(00)02006-2
日期:2001.1
The addition of a series of organocopper (alkyl, vinyl, allyl, and ethynyl) reagents to 3-acyl-N-alkylpyridinium salts, followed by acylation of the intermediate 1,4- or 1,2-dihydropyridines with trichloroacetic anhydride has been studied.
The addition of a series of stabilized carbon nucleophiles to 3-acyl-1-alkylpyridinium salts. followed by acylation of the intermediatedihydropyridines with trichloroacetic anhydride has been studied. The C-4 adducts resulting from the addition of α-(methylsulfanyl)ester enolates have been converted into synthetically useful 1,2,3,4-tetrahydropyridines.