Quinolines copper catalyzed synthesis

Halothiophenes, which are not activated through the presence of —I—M-substituents, undergo substitution smoothly under more forcing conditions with copper salts in pyridine or quinoline. Hence 3-cyanothiophene and 5-methyl-2-cyanothiophene have been obtained from the corresponding bromo compounds. 2-Bromothiophene reacts readily with aliphatic cuprous mercaptides in quinoline at 200°C to give thioethers in high yields. The use of the copper-catalyzed Williamson synthesis of alkoxythiophenes from iodo- or bromo-thiophenes and alcoholate has been mentioned before. The reaction of 2-bromothiophene with acetanilide in nitrobenzene in... 

The most useful approaches to the synthesis of di- and poly-ynes from terminal alkynes are undoubtedly the copper-catalyzed couplings discovered by Glaser (CuCl, NH4OH, EtOH, 02)," Eglinton [Cu(OAc)2, hot pyridine or quinoline, 02], and Hay [Cu(I), tmed, 02]. Some of the many applications of these reactions are discussed in the following. 

In 2011, Cai s group reported a copper-catalyzed tandem reaction of isocyanides with N-(2-haloatyl)propiolamides for the synthesis of pyrrolo[3,2-c]quinolin-4-ones. Highly reactive cyclic organocopper intermediates were... 

Other reactions that have been applied in the Ugi postmodification strategy are the aza-Wittig reaction [80-84] and copper-catalyzed processes [85, 86], More recently, Domling and coworkers have developed a new approach for the synthesis of polycyclic compounds via Ugi MCR followed by a Pictet-Spengler reaction [87-89]. In 2011, apro-tocol for the rapid access to quinolin-2-(l//)-one scaffold was reported by a sequential 4-component Ugi-Knoevenagel condensation [90]. Hulme et al. have introduced a one-pot, two-step protocol for large-scale production of libraries of novel peptidomimetic-like fcM-pyrrolidinone tetrazoles via the Ugi-3CR-azide reaction of tethered keto ester methyl... 

Gabriele B, Mancuso R, Salerno G et al (2007) Novel and convenient synthesis of substituted quinolines by copper- or palladium-catalyzed cyclodehydration of l-(2-aminoaryl)-2-yn-1-ols. J Org Chem 72 6873-6877... 

A carboxyl group is removed from a heterocyclic nucleus in much the same way as from an aromatic nucleus (method 13), i.e., by thermal decomposition. The pyrolysis is catalyzed by copper or copper salts and is frequently carried out in quinoline solution. The reaction is important in the synthesis of various alkyl and halo furans. Furoic acid loses carbon dioxide at its boiling point (205°) to give furan (85%). A series of halo furans have been made in 20-97% yields by pyrolysis of the corresponding halofuroic acids. The 5-iodo acid decarboxylates at a temperature of 140°, whereas the 3- and 5-chloro acids requite copper-bronze catalyst at 250°. ... 

In 2014 several reports described the use of inverse-electron-demand Diels-Alder reactions to furnish naphthalene-based compounds from phthalazine-containing ring systems. Employing nonprecious metal complexes, copper(l) and nickel(O) complexes, instead of silver salts to catalyze formal [4+ 2] cycloadditions of 1,2-diazines and siloxyalkynes, Rawal and his group developed an environmentally friendlier and more economical method for preparing siloxy derivatives of naphthalene, anthracene, and phenanthrene (Scheme 16) (140L3236). In addition, the copper catalyst could also be employed for the synthesis of the corresponding quinolines and isoquinolines. This method provided the respective products in... 

Ahmadi, S. J., Hosseinpour, M., and Sadjadi, S. 2011. Nanocrystalline copper(II) oxide-catalyzed one-pot synthesis of imidazo[l,2-a]quinoline and quinolino[l,2-a]quinazo-line derivatives via a three-component condensation. Synth. Commun. 41(3) 426-435. 

The efficient synthesis of aminoindolizines 53 was successfully achieved in PEG using copper(I) chloride catalyzed three-component reaction of pyridine- or quinolin-2-carboxaldehyde with terminal alkynes and secondary amines (Scheme 30) [54]. The reaction in conventional solvents gave lower yields of the product 53. The structure of the obtained aminoindolizines was confirmed by the X-ray crystallography data (53, R =4-MeC6H4, r2]sjr3=morpholino). 

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