Patent GB-749191-A (GB)
Title: Improvements in or relating to heterocyclic compounds
Inventor: KENDALL JOHN DAVID
IPC: C07D233/42
Filed: 1953-05-06
Abstract: The invention comprises compounds of formula <FORM:0749191/IV(a)/1> and quaternary salts thereof, wherein R1 and R2 are the same or different alkyl or aralkyl groups, or together constitute with the carbon atom to which they are linked an aliphatic carbocyclic ring, R3 is an alkyl group and R4 is a hydrocarbon group, e.g. alkyl, aryl or aralkyl.  The compounds are prepared by alkylating a compound of the above formula in which R3 is hydrogen, and, if desired, heating the resulting compound with an alkyl salt R5X, where R5 is an alkyl group and X is an acid radical, to form the corresponding quaternary salt.  The alkylation of the mercapto group is preferably effected by treatment with an alkyl salt R3X where X is an acid radical (e.g. a halide, sulphate or para-toluene sulphonate), in presence of a strong base (e.g. sodium and potassium hydroxide or alkoxides).  The examples describe the preparation of 2 : 5 : 5-trimethyl-4-ethylthioiminazoleinine; 2 : 5 : 5 - trimethyl-, 5 : 5 - diethyl - 2 - methyl -, 2 : 5 - dimethyl-benzyl -, 2 : 5 - dimethyl - 5 - ethyl -, 5 : 5 - dimethyl - 2 - ethyl -, 5 : 5 cyclopentamethylene-2 - methyl -, 5 : 5 - dimethyl - 2 - benzyl - and 5 : 5 - dimethyl - 2 - phenyl - 4 - methylthioiminazolenine; 1 : 2 : 5 : 5 - tetramethyl - and 1 : 5 : 5 - trimethyl - 2 - ethyl - 4 - methylthioiminazoleninium iodide.  2 : 5 : 5 - Trimethyl -, 5 : 5 - diethyl - 2 - methyl -, 2 : 5 - dimethyl - 5 - ethyl -, 5 : 5 - dimethyl - 2 - ethyl -, 5 : 5 - cyclopentamethylene - 2-methyl -, 5 : 5 - dimethyl - 2 - benzyl - and 2 : 5-dimethyl - 5 - benzyl - 4 - mercaptoiminazoleneine are prepared by heating the appropriate amido-thioamides to give ring closure.  a  : a  - Dimethyl - a  - acetamido -, a  : a  - diethyl - a  - acetamido -, a  - ethyl - a  - methyl - a -acetamido -, a  : a  - dimethyl - a  - propionamido-, a : a  - cyclopentamethylene - a  - acetamido -, a -benzyl - a  - methyl - a  - acetamido - and a  : a  - dimethyl - a  - phenylacetamido - thioacetamide are prepared by reacting hydrogen sulphide with a solution of the appropriate acylamidoacetonitrile dissolved in pyridine and triethylamine.  a  : a  - Dimethyl - acetamido -, a  : a  - diethyl-a  - acetamido -, a  - methyl - a  - ethyl - acetamido-, a  : a  - dimethyl - propionamido -, a  : a  - cyclopentamethylene - acetamido - and a  - benzyl - a -methyl - acetamidoacetonitrile are prepared by condensation of the appropriate acid anhydride and a -aminonitrile.  a  : a -Dimethyl-benzoimidoacetonitrile and a  : a  - dimethyl - phenylacetamidoacetonitrile are similarly prepared from the appropriate acyl chloride and a -aminonitrile in pyridine.  a  : a  - Dimethyl -, a  : a  - diethyl -, a  - methyl-a  - ethyl -, a  : a  - cyclopentamethylene - and a  - methyl - a  - benzyl - aminoacetonitrile are prepared by treating an appropriate ketone with sodium cyanide and ammonium chloride to form the corresponding cyanohydrin, and reacting the latter compound with excess of ammonia gas.  5 : 5 - Dimethyl - 2 - phenyl - 4 - mercapto-iminazolenine is prepared by refluxing 5 : 5-dimethyl - 2 - phenyl - 4 - iminazolone with phosphorus pentasulphide.  5:5 - Dimethyl - 2 - phenyl - 4 - iminazolone is prepared by refluxing an alkaline solution of a :a  - dimethyl - a  - benzamidoacetonitrile with hydrogen peroxide and saturating the cooled solution with carbon dioxide.  Specifications 749,189, 749,190, 749,192 and 749,193, [all in Group XX], are referred to.