[EN] 4(SPIROPIPERIDINYL)METHYL SUBSTITUTED PYRROLIDINES AS MODULATORS OF CHEMOKINE RECEPTOR ACTIVITY [FR] 4(SPIROPIPERIDINYL)METHYL PYRROLIDINES SUBSTITUEES SERVANT DE MODULATEURS DE L'ACTIVITE DES RECEPTEURS DES CHIMIOKINES
On the utility of the azido transfer protocol: synthesis of 2- and 5-azido N-methylimidazoles, 1,3-thiazoles and N-methylpyrazole and their conversion to triazole–azole bisheteroaryls
作者:Paolo Zanirato、Stefano Cerini
DOI:10.1039/b500634a
日期:——
The azido transfer procedure of heteroaryllithium and tosyl azide was used to synthesize selected 2- and 5-azidoazoles. This procedure, which is based on the fragmentation of the appropriate lithium triazene salts 1aâ7a, successfully afforded 2-azido-N-methylimidazole 1, 2-azido-1,3-thiazole 2, 2-azidobenzo-1,3-thiazole 3, 5-azido-N-methylpyrazole 4, 5-azido-N-methylimidazole 6 [via 2-(trimethylsilyl)-5-azido-N-methylimidazole 5], and 5-azido-1,3-thiazole 7 (via 5-lithio-1,3-thiazole), but attempts to prepare 5-azido-2-(trimethylsilyl)-1,3-thiazole 8 from the corresponding triazene 7a failed, affording only the desilylated azide 7 in poor yield. Azides 1â7 underwent 1,3-dipolar cycloaddition when mixed with neat (trimethylsilyl)acetylene, giving 1-heteroaryl-4-trimethylsilyl-1,2,3-triazoles 1bâ7b generally in very high yields.
Regioselectivity in lithiation of 1-methylpyrazole: experimental, density functional theory and multinuclear NMR study
作者:Thomas Balle、Mikael Begtrup、Jerzy W. Jaroszewski、Tommy Liljefors、Per-Ola Norrby
DOI:10.1039/b517607g
日期:——
Reaction of 1-methylpyrazole with n-BuLi in THF followed by reaction with monodeuteromethanol (CH3OD) under kinetically controlled conditions leads to functionalisation at the methyl group, whereas reaction under thermodynamically controlled conditions leads to functionalisation at the pyrazole 5-position. The observed regioselectivity can be correctly predicted, at least qualitatively, using density functional B3LYP/6-31+G(d,p) calculations only when solvation effects (IEFPCM) are taken into account. The 1H,6Li HOESY and NOESY NMR spectra of the thermodynamic product 5-lithio-1-methylpyrazole (5-Li) in [D8]THF are consistent with an oligomeric structure.
STRUCTURE OF 1,4-DIHYDRO-1,4-DIAZOCINE
WITH THREE ANNULATED PYRAZOLE RINGS
作者:G. V. Romanenko、S. E. Tolstikov、V. I. Ovcharenko
DOI:10.1134/s0022476621030094
日期:2021.3
The structures of four products formed in the interaction of lithiated N-methylpyrazole with isoamyl nitrite are determined. One of the reaction products is found to be a 1,4-diazocine derivative–a medium-sized condensed heterocycle in which three pyrazole moieties are annulated to an eight-membered heterocycle and yet another pyrazole moiety is located in a side chain. This molecular structure of the