When Hydrazonoyl Chlorides Meet Terminal Alkynes: Regioselective Copper(I)-Catalysed "Click" Sequential Reactions to 5-Substituted Pyrazoles
作者:Giorgio Molteni
DOI:10.3987/com-20-14268
日期:——
In the presence of catalytic amounts of copper(I) salts, terminal alkynes underwent the formation of copper(I) acetylides that enabled their nucleophilic addition onto hydrazonoyl chlorides followed by spontaneous cyclisation of the resulting alkynylhydrazone intermediate. This sequential reaction sequence was exploited as a facile and regioselective synthesis of 1,3,5-substituted pyrazoles. A catalytic
Synthesis and Characterization of Oxadisilole-Fused 1<i>H</i>-Benzo[<i>f</i>]indazoles and 1<i>H</i>-Naphtho[2,3-<i>f</i>]indazoles
作者:Yajuan Zhang、Xuyan Ma、Yali Chen、Xuanming Chen、Lei Guo、Weiguo Cao、Jie Chen、Man Shing Wong
DOI:10.1002/ejoc.201300110
日期:2013.5
1H-benzo[f]- and 1H-naphtho[2,3-f]indazoles have been synthesized by the 1,3-dipolar cycloaddition reactions of benzo- or naphtho-oxabicycloalkenes with nitrile imines generated in situ from N-arylhydrazonoyl chlorides followed by deoxygenation and aromatization. The photophysical, redox and thermal properties of these compounds have been characterized. Some of the indazoles show potential as deep-blue emitters
One-flask synthesis of 1,3,5-trisubstituted 1,2,4-triazoles from nitriles and hydrazonoyl chlorides via 1,3-dipolar cycloaddition.
一瓶法合成1,3,5-三取代-1,2,4-三唑,从腈和叠氮酰氯通过1,3-偶极环加成。
Uncommon aqueous media for nitrilimine cycloadditions. I. Synthetic and mechanistic aspects in the formation of 1-aryl-5-substituted-4,5-dihydropyrazoles
作者:Giorgio Molteni、Alessandro Ponti、Marco Orlandi
DOI:10.1039/b205063c
日期:2002.9.23
A number of 1-aryl-5-substituted-4,5-dihydropyrazoles 4 have been synthesised by 1,3-dipolar cycloaddition of variously substituted nitrilimines 2 onto the appropriate alkenyl dipolarophiles 3 in aqueous media and in the presence of a surfactant. Under these conditions, uncommon for the large majority of [3 + 2] cycloadditions, the electronic features of both the cycloaddends strongly dictate the reaction outcome. Clean and fast cycloadditions were observed between electron-rich nitrilimines and electron-poor dipolarophiles, while the reversal of the electronic features of the reactants gave poor results. Changes in surfactant concentration leads to some novel mechanistic insights.
15N NMR spectroscopy of partially saturated pyrazoles
作者:Lara De Benassuti、Teresa Recca、Giorgio Molteni
DOI:10.1016/j.tet.2007.02.063
日期:2007.4
namely 1-(4-substituted)phenyl-3-methoxycarbonyl-5-ethoxycarbonyl-4,5-dihydropyrazoles, were submitted to extensive 15N NMR spectroscopic analyses, performed in natural abundance. Nitrogen chemicalshifts were measured by means of INEPT and HMBC experiments, while long range proton–nitrogen scalar coupling values were taken through J-HMBC experiments. A linear plot between nitrogen chemicalshifts and
将部分饱和的吡唑,即1-(4-取代)苯基-3-甲氧基羰基-5-乙氧基羰基-4,5-二氢吡唑,进行大量的15 N NMR光谱分析,以自然丰度进行。氮化学位移通过INEPT和HMBC实验测量,而远距离质子-氮标量耦合值通过J -HMBC实验获得。氮化学位移和哈米特之间的线性图σ p观察到,使我们能够定量地涉及观察到的化学位移的取代基的电子特征的4,5-二氢吡唑环的1-位上。