Indoles reaction with copper chloride

The reaction of indole (38) with copper(II) chloride also proceeds dirough a cation radical intermediate (39) to give mainly 2-chloroindole (40), together with a dimeric by-product (41), as shown in equation (15) ... 

Indolines 41, 42 are dehydrogenated by anhydrous copper chloride in pyridine to the corresponding indoles 41a, 42a [33, 35] with yields of up to 40%. The production of 5-(diethoxyphosphoryl)indoline (43) and 5-(dicthoxyphosphoryl[indole (43a) from 5-bromoindoline (5-bromoindole) and trialkyl phosphites by the Arbuzov reaction, catalyzed by nickel chloride has been described [35] ... 

The reaction of zinc-copper reagents with acid chlorides has a remarkable generality [7,19] and has found many applications in synthesis (Scheme 9-30) [16,59-64]. The treatment of silyl-protected o-aminated benzylic zinc-copper derivatives such as 33 with an acid chloride leads to a 2-substituted indole 34. Aromatic and heterocyclic zinc compounds provide polyfunctional aromatic or heterocyclic ketones like 35 (see Section 9.6.8 Scheme 9-31) [60]. 

The aryl chlorides and aryl bromides are easily prepared by treatment of the arylthallium(III) bis(trifluoroacetates) with the corresponding copper(I) or copper(II) halides. The best yields were obtained with the copper(II) halides in dioxane under reflux. 2 These reactions have been successfully applied by Somei et al to the synthesis of indole derivatives by reaction of the arylthallium compounds with copper(II) salts in DMF. 127,133,134... 

Another type of o-aminobenzyl synthon is based on o-(bis-trimethylsilylaminobenzyl)copper-zinc reagents <89TL4795>. These are prepared from the corresponding benzylic bromides by reaction with zinc, followed by addition of cuprous cyanide. These reagents react with acid chlorides to give 2-substituted indoles. Since the reactions proceed by C-acylation rather than iV-acylation, the conditions required for cyclization are mild and typically the C-acylated intermediates are not isolated. 

Indole has been separated from carbazole and diphenylamine on silica gel, copper sulphate-impregnated silica gel, on alumina and on cellulose with aqueous and non-aqueous systems (212). The color reactions with six different spray reagents following two-dimensional separations on silica gel H have been studied (213) for a wide range of indoles and skatole on cellulose detected by its fluorescence with 2,4-dinitrophenylpyridinium chloride (213a). Indole and oxindole alkaloids have been separated in 10 neutral and 10 alkaline solvents (214). 

EtOH). No methoxyl is present. It forms a series of crystalline double chlorides with cadmium, zinc or copper, does not give the thalleioquin reaction, and solutions of its sulphate are not fluorescent. It is diacidie and forms two series of salts of which the nitrate, B. HNOj, crystallises in minute prisms, m.p. 196°, insoluble in water. Cinchonamine hydrochloride, B. HCl, laminae or B. HCl. HjO, cubical crystals, has been suggested for use in the estimation of nitrates. When warmed with strong nitric acid the alkaloid furnishes dinitrocinchonamine. It gives an amorphous, monoacetyl derivative, and forms a methiodide, m.p. 208 , which with silver oxide yields an amorphous methylcinchonamine. Raymond-Hamet found that cinchonamine ves typical indole colour reactions and is probably an indole alkaloid. This seems to have been... 

Indolyl A-Grignards, "" or even better their zinc analogues, undergo reaction predominantly at C-3 with a variety of carbon electrophiles such as aldehydes, ketones and acid halides, or reactive halo-hetero-cycles. Including aluminium chloride in the zinc reactions produces high yields of 3-acyl-indoles. The copper-catalysed reactions of indolyl-A-Grignards with A-t-butoxycarbonyl-aziridines also proceed well at C-3. ... 

Oxidative Cyclization and Ring Contraction. An intramolecular cychzation/carboalkoxylation reaction takes place when 2-(penten-l-yl)-indole is treated with Pd2(dba)3 and a stoichiometric amount of copper (II) chloride in methanol under CO (1 atm). The polycyclic indole derivative was obtained in 68% yield, along with the minor C(3)-chlorinated by-product. A het-erobimetaUic Pd/Cu complex was proposed as the active catalyst in this transformation (eq 47). ... 

Finally, copper(II) catalysis was reported to be efficient in the formation of complex indolizine templates constructed Irom pyridine via a three-component reaction. When an excess of pyridine is reacted with equimolar amount of 1,4-naphthoquinone and dimethyl butynedioate (1 equiv) in the presence of copper(II) chloride under aerobic conditions, benzo[/]pyrido[l,2-a]indole-6,ll-dione is formed in 93% yield (eq 39). 

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