US1774650A - 5-halogen-2-cyano-3-amino-1-methyl-benzene compounds - Google Patents

Description

Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE ERWIN HOFFA AND HANS HEYNA, OF FRANKFORT- ON-THE-MIAIN-HOCHST, GERMANY, ASSIGNORS TO GENERAL .ANILINE VJORKS, INC., 013 NEW YORK, N. Y., A CORPORA- 'IION OF DELAWARE 5-HALOGEN-2-CYANO-3-AMINO-1-METI-IYL-IBENZENE COMPOUNDS No Drawing. Application filed August 2, 1928, Seria1 No. 297,101, and in Germany August 11, 1927.

Our present invention relates to 5-halogen-2-cyano-3 amino-l-methyl-benzene 7 compounds.

Various processes have already been disclosed by which it is possible to obtain 4.6- substituted hydroxythionaphthenes and thioindigo dyestuffs respectively, particularly the commercially valuable i-methyl-G-halo gen-hydroxythionaphthenes and oxidation or condensation products thereof. These processes are distinguished from each other by the kind of starting material used for the reaction and consequently by the differentsteps of the processes. All of the hitherto known processes can only be carried out in numerous intermediate stages which sometimes involve technical difficulties.

In order to obtain the important l-methyl- 6-halogen thioindigos by starting from the Q-amino-S-nitro 5-halogen-1 methylbenzenes being easily accessible in practice and having the formula:

ON HlgLINO:

which are formed as intermediate products, so as to obtain the carboxylic acids, but subjecting them to reduction. There are thus obtained the hitherto unknown 2-cyano-3- amino-5-halogen-1-methylbenzenes of the formula:

ON 111 Olin,

with the aid of these compounds there can be prepared the 5-halogen-l-methylbenzene- 2-cyano-8-thioglycollic acids of the formula:

Hlg somooon The transformation of the 2-cyano-3-amino-5-halogen-l-methylbenzenes into the corresponding cyano-thioglycollic acids can be effected by way of the xanthogen esters though in the course of this reaction an alkaline saponification is required for obtaining the corresponding ortho-cyanomercaptans and though the cyano group could have been saponified to the carboxyl group. It is, however, a surprising fact that the cyano group proved to be stable.

The ortho-aminonitriles can be transformed into the ortho-cyano-thioglycollic acids also in other ways, for instance by diazoting the ortho-aminonitriles, transforming the diazo compounds thus obtained by the action of alkalidior polysulfides and subsequent reduction into the mercaptan and finally causing the latter to react with chloroacetic acid according to any of the known methods.

In order to produce from the aforementioned compounds the corresponding hydroxythionaphthenes, it is possible to proceed according to German patent specifications Nos. 184,496 and 190,674 to Kalle & Co. Aktiengesellschaft or according to the oopending U. S. patent applications Ser. Nos. 211,850, 211,851 which have matured respectively into patents Nos. 1,703,15, dated February 26, 1929, and 1,7 25,080, dated August 20, 1929, and Serial No. 211,852 filed August 9, 1927. It is cheaper to carry out the transformation by one of these processes than by the process of closing the ring described in U. S. patent specification No. 892,897.

To more clearly explain our invention we give herewith asingle example but it is to be understood that we do not limit ourselves to the details of this example. The parts are by weight:

19 parts of 5-chloro-2-cyano-3-nitro-1-methylbenzene melting at 97 C. to 99 C. are gradually introduced at 0., while stirring, into a mixture of 80 parts of iron, 40 parts of water and 10 parts of glacial acetic acid and the whole is further stirred at 80 C. until the reduction is finished. The mass is cooled, filtered by suction and the base is eliminated in the usual manner from the residue remaining on the filter. The 5-cl1loro-2- cyano-3-amino-l-methylbenzene dissolves in the heat in dilute hydrochloric acid with for mation of the hydrochloride and crystallizes from benzene in the form of white needles melting at 100 C. to 101 C. It is sparingly soluble in water, more easily soluble in benzone and readily soluble in alcohol and ether.

e claim:

1. As new products, compounds of the formula:

Hlg NH:

wherein Hlg stands for a halogen atom, being white crystallized bodies.

2. As a new product, the compound of the "following formula:

being a white crystallized body melting at 100 C. to 101 (3., sparingly soluble in water, more easily soluble in benzene and readily soluble in alcohol and ether.

In testimony whereof, We aifix our signatures.

ERWVIN HOFFA. HANS HEYNA.