Pyridazine N-Oxides as Precursors of Metallocarbenes: Rhodium-Catalyzed Transannulation with Pyrroles
摘要:
Pyridazine N-oxides are used for the first time as precursors of metallocarbenes. These nitrogen-rich heterocycles led to the discovery of a novel acceptor and donor-acceptor enalcarbenoids. The synthetic utility of these metallocarbenes was demonstrated in the rhodium-catalyzed denitrogenative transannulation of pyridazine N-oxides with pyrroles to the valuable alkyl, 7-aryl, and 7-styryl indoles. The transannulation strategy was applied to the synthesis of a potent anticancer agent.
Metal-catalyzed coupling process comprising reacting a compound of general formula 1 with a compound A-X, to obtain a compound of general formula 2, which may further be converted to a compound of general formula 3
An efficient and general protocol for the decarboxylative cross-coupling of pyridazine-3-carboxylicacids with aryl-bromides has been described. This method provides a new avenue for the synthesis of 3-arylpyridazines via decarboxylative cross-coupling strategy by employing the dual-catalyst system of Pd(PPh3)4/Cu2O in the presence of Li2CO3 at 160 °C in DMA.
已经描述了哒嗪-3-羧酸与芳基溴化物的脱羧交叉偶联的有效且通用的方案。该方法为Pd(PPh 3)4 / Cu 2 O的双催化剂体系在160℃下Li 2 CO 3存在下通过Pd(PPh 3)4 / Cu 2 O双催化剂体系的合成提供了一种新的途径。 DMA。
Lewis Acid Directed Regioselective Metalations of Pyridazine
Mono‐ or bidentate boron Lewisacids trigger a regioselective magnesiation or zincation of pyridazine in position C3 (ortho product) or C4 (meta product). The regioselectivity of the metalation was rationalized with the help of calculated pKa values of both pyridazine and pyridazine/Lewisacid complexes.
单或二齿硼路易斯酸在位置C3(邻位产物)或C4(间位产物)处引发哒嗪的区域选择性镁化或锌化。借助于计算的哒嗪和哒嗪/路易斯酸络合物的p K a值,使金属化的区域选择性合理化。
Direct C–H photoarylation of diazines using aryldiazonium salts and visible-light
作者:Rodrigo C. Silva、Lucas F. Villela、Timothy J. Brocksom、Kleber T. de Oliveira
DOI:10.1039/d0ra06876d
日期:——
demonstrate the efficacy of this protocol by the scope with electron-donor, -neutral, and -withdrawing groups attached at the ortho, meta, and para positions of the aryldiazonium salts; the results are better than those reported for ruthenium-complex mediated photoarylations. Additionally, we demonstrate the robustness of this methodology with a 5 mmol scaled-up experiment. Mechanistic studies were carried
New pyrrolopyridazinederivatives were synthesized as potential blueorganicluminophors. Three different classes of pyrrolopyridazinederivatives were made, for example, aryl groups directly connected to the core PPY (pyrrolo[1,2-b]pyridazine-5,6,7-tricarboxylic acid trimethyl ester) moiety, aryl groups connected to the PPY via a vinylene linker and aryl groups connected to the PPY via an acetylene
合成了新的吡咯并哒嗪衍生物,作为潜在的蓝色有机发光体。制备了三种不同种类的吡咯并哒嗪衍生物,例如,直接连接到核心PPY(吡咯并[1,2 - b ]哒嗪-5,6,7-三羧酸三甲酯)部分上的芳基,将芳基连接到PPY上通过亚乙烯基连接基和通过乙炔连接基连接到PPY的芳基。他们的光学和电化学性能进行了比较。衍生物2之一显示出相对量子产率高达0.9。乙烯基桥联吡咯并哒嗪系列化合物8的特征在于其X射线晶体结构分析。