Formylation and Cyanoethylation of Substituted Indoles

Abstract

The preparation of aromatic aldehydes by the use of N-methylformanilide and phosphorus oxychloride was first accomplished by Vilsmeier and Haack (1) who used this method for the synthesis of p-alkylaminobenzaldehydes. In a series of patents, Kaliseher, Scheyer, and Keller (2) reported that the reaction is applicable to certain phenolic ethers and aromatic hydrocarbons, and these claims were verified by Wood and Bost (3). Application of the reaction to indole derivatives unsubstituted in the 3-position was made by Wolff and Werner (4) who prepared 2-phenylindole-3-aldehyde, l-methyl-2-phenylindole-3-aldehyde, and others. The preparation of 2-phenylindole-3-aldehyde by the method of Wolff and Werner has been repeated; consistently high yields (90%) were obtained.In uder to establish the structure of 2-phenylindole-3-aldehyde with greater certainty, it was prepared from 2-phenylindole by the use of the Reimer-Tiemann reagents, chloroform and potassium hydroxide. The modification employed

Recent Studies in the Field of Indole Compounds

“…Two compounds (33 and 35), both 2-substituted heterocyclic tryptamines, showed appreciable activity in inhibiting spontaneous motor activity of mice in the actophotometer (light box). Three compounds (22,29,32), all tertiary amines, share the oxytoxic activity present in some of the indole-containing natural products.…”

Electrocatalytic Oxidation of Amines on a Mediator‐Modified Electrode by Electrochemical Copolymerization of Nitroxyl Radical Precursor Containing Pyrrole Side Chain and Bithiophene

“…4‐(3‐(Pyrrole‐1‐yl)propoxycarbonyl)‐TEMPO was prepared by the procedure of a previous report 13, 14. 2,2′‐Bithiophene and tetra‐ n ‐butylammonium perchlorate (TBAP) were purchased from Tokyo Chemical Industry Co., Ltd. and Nacalai Tesque, Inc., respectively.…”

Modern Friedel-Crafts chemistry. Part 35. New synthetic approach to substituted indolo[2,1-a][2]benzazepines and indolo[2,1-a]isoquinolines via Friedel-Crafts cyclialkylations

“…Path 2 comprised the conversion of substrate 3 to tertiary alcohols 6d-f via three consecutive steps: (i) cyanoethylation 41 of 3 with acrylonitrile (7) in the presence of Triton B, (ii) reaction of the resulting nitrile 8 with one equivalent of Grignard reagents to afford ketones 9a,b and (iii) reaction of ketones 9a,b with Grignard reagents to give alcohols 6d-f (R 1 # R 2 ) ( The third route (path 3) encompassed the production of alcohols 12a-c. These were prepared smoothly through the N-alkylation of 3 with 1-bromopropan-2-one (10) to give 1-(7-methyl-2-phenyl-1H-indol-1-yl)propan-2-one (11).…”