Patent GB-1210568-A (GB)
Title: 2-aminomethylindole derivatives and a process for preparing 1,4-benzodiazepine derivatives
Inventor: YAMAMOTO H
IPC: C07D209/04
Filed: 1968-04-11
Abstract: 1,210,568. 2-Aminomethylindole derivatives and a process for preparing 1,4-benzodiazepine derivatives. SUMITOMO CHEMICAL CO. Ltd. 11 April, 1968 [22 Sept., 1967; 27 Sept., 1967 (7); 9 Oct., 1967 (2); 18 Oct., 1967; 2 Nov., 1967 (3); 6 Nov., 1967; 8 Nov., 1967; 9 Dec., 1967; 15 Dec., 1967; 21 Dec., 1967; 10 Jan., 1968], No. 17646/68. Heading C2C. Novel 2-aminomethylindole derivatives of the general Formula II  wherein R 1  is hydrogen, an alkyl group having 1 to 3 carbon atoms or a cycloalkylmethyl group having 4 to 7 carbon atoms, and R 2  is hydrogen or a halogen and their salts are prepared by reduction of the corresponding 2-cyanomethyl derivatives or 2-thioamido or 2-carboxamido derivatives.  The invention also comprises a process for the preparation of 1,4-benzodiazepine derivatives having the general Formula I wherein R 1  and R 2  are as defined above which comprises cyclising a compound of the Formula II defined above or a salt thereof by treating it with an oxidising agent. The 2-cyanomethyl indole derivatives are prepared by heating the corresponding 2-thioamido- or 2-carboxamido-indole derivatives. The 2-thioamido-indole derivatives are prepared by treating the corresponding 2-carboxamido-derivatives with phosphorus pentasulphide. The 2 - carboxamido - indole derivatives are prepared by (i) treating the corresponding carboxylic acid or its halide with ammonia; (ii) reacting phenylpyruvic acid derivatives having the Formula III wherein R 3  is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a benzyl group with phenylhydrazine derivatives having the Formula IV wherein R 1  and R 2  are as defined above, in the presence of an inert solvent e.g. a lower alcohol, to yield the corresponding phenylhydrazones, treating the latter in the presence of an acid to yield indole-2-carboxylic acid derivatives of the Formula VI and treating these acid derivatives with ammonia or hydroxylamine; (iii) reacting #-keto acid ester derivatives having'the Formula VII wherein R 5  is an alkyl group having 1 to 4 carbon atoms or a benzyl group, and R 4  is an alkyl group having 1 to 4 carbon atoms, with R 2 -substituted benzene diazonium halides wherein R 2  is as defined above, in the presence of a strong base to give the corresponding phenylhydrazone derivatives, treating the latter in the presence of an acid to give indole-2- carboxylic acid ester derivatives, alkylating these to give the corresponding N-alkylindole-2- carboxylic acid ester derivatives, converting these to the corresponding acid and treating this with ammonia or hydroxylamine; (iv) as method (iii) above, except that a weak base is present and the corresponding azo derivatives (instead of phenylhydrazone derivatives) are obtained. These are treated with an acid to give indole-2-carboxylic acid ester derivatives which are then treated as in (iii) above. The N-unsubstituted indole derivatives may be converted to N-R 1  (where R 1  is not a hydrogen atom) indole derivatives by the use of alkylating agents. The salts of the benzodiazepine derivatives of the Formula I above are prepared by treatment of the latter with acids. The compounds of Formula I are known as remarkably effectiv tranquillizers, muscle relaxants, anti-convulsants and hypnotics. Many examples of the various compounds mentioned above are given in the Specification, together with their preparations.