Selective Synthesis of Indazolo[2,3‐
<i>a</i>
]quinolines via Rh(III)‐Catalyzed Oxidant‐Free [4+2] or [5+1] Annulation of 2‐Aryl‐2
<i>H</i>
‐indazoles with
<i>α</i>
‐Diazo Carbonyl Compounds
作者:Shenghai Guo、Lincong Sun、Xuzhuo Li、Xinying Zhang、Xuesen Fan
DOI:10.1002/adsc.201901422
日期:2020.2.21
A selective synthesis of 5,6‐disubstituted and 5‐substituted indazolo[2,3‐a]quinolines through a Rh(III)‐catalyzed oxidant‐free annulation of 2‐aryl‐2H‐indazoles with α‐diazo carbonyl compounds is reported. With 2‐aryl‐2H‐indazoles as the substrates, α‐diazo carbonyl compounds could act as a C2 synthon to afford 5,6‐disubstituted indazolo[2,3‐a]quinolines via a Rh(III)‐catalyzed [4+2] annulation. On
通过Rh(III)催化的2-芳基-2 H-吲唑与α-重氮羰基化合物的无氧化剂环氧化反应选择性合成5,6-二取代和5-取代的吲唑并[2,3- a ]喹啉是报告。以2-芳基-2 H-吲唑为底物,α-重氮羰基化合物可作为C2合成子,通过Rh(III)催化[ 5,6-二取代的吲唑并[2,3- a ]喹啉] [4 +2]。另一方面,当使用2-芳基-3-甲酰基-2 H-吲唑类作为底物时,α-重氮羰基化合物转变为C1合成子,需要经历更复杂的[5 + 1]环化工艺来提供5位取代的吲哚并[2,3- a ]喹啉。
Reduction of nitro- and nitroso-compounds by tervalent phosphorus reagents. Part XI. A kinetic study of the effects of varying the reagent and the nitro-compound in the conversion of o-nitrobenzylideneamines to 2-substituted indazoles
作者:Margaret-Ann Armour、J. I. G. Cadogan、David S. B. Grace
DOI:10.1039/p29750001185
日期:——
A kinetic study of the effects of varying the phosphorus reagent and substituents in the nitro-compound in the reductivecyclisation of o-nitrobenzylideneamines to 2-substituted indazoles has been made. First-order rate constants vary from 8.2 to 52.2 × 10–5 s–1 for the triethyl phosphite-induced reduction of N-o-nitrobenzylideneanilines [o-NO2C6H4CHNC6H4Y; Y =p-MeO, p-Me, H, p-CI, p-Br, p-CO2Et, p-CN
动力学研究了在邻硝基亚苄基胺还原成2-取代的吲唑的环化反应中改变硝基化合物中磷试剂和取代基的作用。一级速率常数从8.2变化至52.2×10 -5小号-1为的亚磷酸三乙酯诱导的减少ñ - ö -nitrobenzylideneanilines [ ø -NO 2 ç 6 ħ 4 CH NC 6 H ^ 4 ÿ; Y = p -MeO,p -Me,H,p -Cl,p -Br,p -CO 2等等,p -CN。p -NO 2,或ö ] -CI和Ñ -5-氯-2- nitrobenzylideneaniline,并略有不同的5至6×10 -5小号-1为ö -nitrobenzylideneamines [ ø -NO 2 ·C 6 H ^ 4 · CH NR; R = Me中,乙基,丙基我,或卜Ñ ]。这些反应的产物是相应的2-芳基-(芳基= C 6 H 4 Y)和2-烷基-(烷基= R)-吲唑。这
A Biphilic Phosphetane Catalyzes N–N Bond-Forming Cadogan Heterocyclization via P<sup>III</sup>/P<sup>V</sup>═O Redox Cycling
作者:Trevor V. Nykaza、Tyler S. Harrison、Avipsa Ghosh、Rachel A. Putnik、Alexander T. Radosevich
DOI:10.1021/jacs.7b03260
日期:2017.5.24
chemoselective catalytic synthesis of 2H-indazoles, 2H-benzotriazoles, and related fused heterocyclic systems with good functional group compatibility. On the basis of both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic PIII/PV═O cycling, where DFT modeling suggests a turnover-limiting (3+1) cheletropic addition between the phosphetane catalyst and nitroarene
Electrochemical Radical–Radical Cross-Coupling Approach between Sodium Sulfinates and 2<i>H</i>-Indazoles to 3-Sulfonylated 2<i>H</i>-Indazoles
作者:Wansoo Kim、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.0c02144
日期:2020.8.21
A direct cross-coupling between sodium sulfinates and 2H-indazoles has been developed under electrochemical conditions. The utilization of a graphite anode and platinum cathode in an undivided cell with a constant current of 7 mA allowed the concurrent oxidations of sulfinates and 2H-indazoles to sulfonyl radical and radical cationic 2H-indazoles, facilitating the direct radical–radical coupling strategy
The Mills reaction and cyclization of readily available 2‐aminobenzyl alcohols and nitrosobenzenes using thionyl bromide provided 2H‐indazoles in up to 88 % yields. In the metal‐free process, acetic acid played a crucial role for the both Mills reaction and cyclization. A brominated 2H‐indazole could also be obtained through the one‐pot sequence.