GB807679A - New substituted hydantoin and thiohydantoin - Google Patents

Abstract

The invention comprises hydantoin compounds of the general formula <FORM:0807679/IV (b)/1> wherein X represents an oxygen or sulphur atom, and the preparation thereof (a) in the case where X represents an oxygen atom by reacting cyclo-octanone, hydrogen cyanide or an alkali metal cyanide such as sodium or potassium cyanide, ammonia or an ammonium salt such as ammonium chloride, and carbon dioxide (the ammonia or ammonium salt and carbon dioxide may be present in the form of ammonium carbonate or ammonium carbamate), and (b) by reacting a compound of the formula <FORM:0807679/IV (b)/2> or a salt thereof such as the hydrochloride salt, and cyanic acid or an alkali metal cyanate such as sodium cyanate respectively followed by hydrolysis in an acid medium, e.g. an aqueous mineral acid medium-particularly aqueous hydrochloric acid, and the preparation thereof (c) in the case where X represents a sulphur atom by heating 5:5-cycloheptamethylene-2,4-dithiohydantoin with either ammonia or a primary amine for example monoethanolamine, in an aqueous medium, e.g. 33 per cent by weight of aqueous monoethanolamine, followed by hydrolysis of the product so formed in an acid medium, e.g. aqueous hydrochloric acid medium. Reaction (a) above is preferably carried out at a temperature of about 50 DEG to 55 DEG C. in the presence of an inert solvent or diluent, e.g. an aqueous medium such as water or aqueous alcohol (preferably ethanol containing 50 per cent by weight of water), and in this case it is preferable to use one molecular proportion of cyclo-octanone, about 2 molecular proportions of an alkali metal and about 4 molecular proportions of ammonium carbonate. Reaction (a) may be modified in that the cyclo-octanone and hydrogen cyanide or alkali metal cyanide are replaced by the corresponding cyclo-octanone cyanohydrin, or the cyclo-octanone, hydrogen cyanide or alkali metal cyanide are replaced by the corresponding cyclo-octanone aminonitrile, or the cyclo-octanone is replaced by a functional derivative of cyclo-octanone which under the conditions of the reaction reacts in effect like cyclo-octanone, e.g. an alkali metal bisulphite addition product thereof. Reaction (b) may be carried out in the presence of an inert diluent or solvent such as aqueous acetic acid. Reaction (b) may be modified in that the reactant of the above general formula is generated in situ by the interaction of the corresponding cyclooctanone cyanohydrin and ammonia. The cyclo-octanone cyanohydrin may also be formed in situ from cyclo-octanone in a medium containing hydrogen cyanide or an alkali metal cyanide such as sodium cyanide. In the examples 5,5 - cycloheptamethylenehydantoin and 5,5 - cycloheptamethylene - 2 - thiohydantoin are prepared. 1 - Amino - 1 - cyano - cyclo - octane hydrochloride is prepared by reacting cyclo-octanone, potassium cyanide and ammonium chloride in aqueous ethanol to form the free base which is then treated with hydrogen chloride.