New Access to 2,3-Disubstituted Quinolines through Cyclization of o-Alkynylisocyanobenzenes
摘要:
[GRAPHICS]o-Alkynylisocyanobenzenes underwent nucleophile-induced intramolecular cyclization to give 2,3-disubstituted quinoline derivatives in high yields. In addition to the oxygen and nitrogen nucleophiles such as methanol and diethylamine, the nucleophilic carbon of the enolate of malonate induced the cyclization effectively. Reaction of 1,4-di(trimethylsilylethynyl)-2,3-diisocyanobenzene with methanol afforded 2,9-dimethoxy-1,10-phenanthroline in good yield.
Mild Access to N-Formylation of Primary Amines using Ethers as C1 Synthons under Metal-Free Conditions
作者:Mohana Reddy Mutra、Ganesh Kumar Dhandabani、Jeh-Jeng Wang
DOI:10.1002/adsc.201800783
日期:2018.10.18
A new synthetic protocol has been developed for the synthesis of N‐formamide derivatives using ethers as a C1 synthon undermetal‐free reaction conditions. The reaction is proposed to proceed through C−H functionalization, C−O cleavage, and C−N bond formation. This protocol is applicable to a variety of primary amines resulting in N‐formamides in moderate to good yields. 1,4‐dioxane was chosen as best
the corresponding bis-thiolated indolederivatives. The advantages of the reaction include metal-free, room-temperature, mild reaction conditions and broad functional group compatibility. The reaction proceeds via nucleophilic addition of an alkanethiol to an isonitrile moiety, 5-exo cyclization, followed by nucleophilic addition of an alkanethiol to a 3-alkylidene indole intermediate. Density functional
Diverse 2-sulfonyl- and 2-thiocyanato-3-substituted quinolines were synthesized from o-alkynylisocyanobenzenes by nucleophilic addition of the respective sulfinate sodium salts and ammonium thiocyanate to the isocyanide moiety followed by cyclization. The salient features of the methodology include metal-free, ambient temperature and mild reaction conditions, ease of reagent handling, and broad functional
The cyclization reaction of various 2-ethynylanilines, which were easily synthesized from 2-haloanilines by the palladium-catalyzed reaction with terminal alkynes, with tetrabutylammonium fluoride (TBAF) to yield 2-substituted indoles proceeded at refluxing or room temperature in THF in excellent yields without affecting the bromo, chloro, cyano, ethoxycarbonyl, and ethynyl groups.
A facile synthesis of various functionalized 3-substituted quinolin-2(1H)-ones through Ag(I) nitrate-catalyzed cyclization of o-alkynylisocyanobenzenes is described. The reaction allows rapid and convenient access to 3-substituted quinolin-2(1H)-one scaffolds in moderate to good yields.