ES260796A1 - Substituted indoles - Google Patents

Abstract

The invention comprises compounds of the general formula: <FORM:0951112/C2/1> and salts and esters thereof wherein the dotted line in the 2(3)-position indicates that a single or double bond is present there, R1 and R3 are hydrogen atoms or C1-5-alkyl or C2-5 alkenyl groups, R2 is a hydrogen atom or a hydrocarbon or a substituted hydrocarbon group, R4 is a halogen atom or a hydrocarbon, hydroxy, nitro, amino substituted amino, mercapto, substituted mercapto, cyano, haloalkyl acyl, carboxy or derivatized carboxy group, R5 is hydrocarbonyl, R6 is a hydrogen atom or a hydrocarbonoxy group, a is 1, 2, 3 or 4 and b is 0, 1, 2 or 3 and the preparation thereof by reacting together, in an alkaline medium either (a) an appropriate benzyl ester of a strong acid or (b) an appropriate benzyl alcohol and an ester of a strong acid, with a compound of the formula: <FORM:0951112/C2/2> wherein Y is a hydrogen atom or a hydrocarbon group or (where the 2(3) linkage is saturated) by hydrogenating the corresponding D 2(3)-compound. The group R2 may be an alkyl, alkenyl, cycloaliphatic, aryl or aralkyl group or a substituted group such as haloalkyl, hydroxyalkyl, halophenyl or alkoxyphenyl. Substituted amino groups of R4 may include acylamino, amino oxide, urethane, alkyl- and dialkyl-amino, amidino, acylamidino, hydrazino sulphonyl-amino and alkoxy amino groups, and derivatized carboxyl groups may include alkali metal salts, alkyl esters of the carboxyl residue, aldehydes, azides, amides or hydrazides. The free acids may be converted into salts such as the sodium, potassium or ammonium glucosamine, morpholine, diethylamine and choline salts. When R4 is a basic radical it is preferred to carry out the aralkylation with the nitro substituted indole and subsequently reduce the nitro group to the amino group. The amino group may be acylated in a further reaction. Indolyl aliphatic acids used as starting materials are prepared by reacting an appropriately substituted phenylhydrazine with a b -keto aliphatic acid or by introducing the carboxylic acid residue into the 3-position under Mannich reaction conditions with formaldehyde-dialkyl-amine to produce a gramine and reacting this with an alkali metal cyanide and hydrolysing the nitrile. Substituted phenyl hydrazines such as 4-methoxy -2- methylphenylhydrazine are prepared by reduction of the diazonium salt of the corresponding amine. Ethyl a -(2, 5-dimethyl-2, 3-dihydro -3- indolyl)-acetate is prepared by reduction of the indole derivative with tin and hydrochloric acid. U.S.A. Specification 2,825,734 is referred to.