GB807678A - New substituted hydantoins and thiohydantoins - Google Patents

Abstract

The invention comprises hydantoin compounds of the general formula <FORM:0807678/IV (b)/1> wherein one of R1 and R2 represents hydrogen and the other a methyl radical and X represents an oxygen or sulphur atom, and the preparation thereof (a) in the case where X represents oxygen by reacting 3-methyl- or 4-methyl-cycloheptanone, 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 general formula <FORM:0807678/IV (b)/2> wherein R1 and R2 have the above significance, 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. on aqueous mineral acid medium-particularly aqueous hydrochloric acid, and the preparation thereof (c) in the case where X represents a sulphur atom by reacting a di-thiohydantoin compound of the general formula <FORM:0807678/IV (b)/3> wherein R1 and R2 have the above significance, with ammonia or a primary organic amine such as 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 such as an 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 3-methyl- or 4-methyl-cycloheptanone, about 2 molecular proportions of an alkali metal cyanide and about 4 molecular proportions of ammonium carbonate. Reaction (a) may be modified in that the 3 - methyl - or 4 - methyl - cycloheptanone and the hydrogen cyanide or alkali metal cyanide are replaced by the corresponding 3-methyl - or 4 - methyl - cycloheptanone cyanohydrin, or the 3-methyl- or 4-methyl-cycloheptanone, the hydrogen cyanide or alkali metal cyanide and ammonia or ammonium salt are replaced by the corresponding 3-methyl- or 4-methyl-cycloheptanone aminonitrile, or the 3-methyl- or 4-methyl-cycloheptanone is replaced by a functional derivative of 3-methyl- or 4-methyl-cycloheptanone which under the conditions of the reaction reacts in effect like 3-methyl- or 4-methyl-cycloheptanone, 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 general formula given above is generated in situ by the interaction of the corresponding 3-methyl- or 4-methylcycloheptanone cyanohydrin and ammonia, the 3-methyl- or 4-methyl-cycloheptanone cyanohydrin may also be formed in situ from the corresponding 3 - methyl - or 4 - methyl - cycloheptanone in a medium containing hydrogen cyanide or an alkali metal cyanide, e.g. sodium cyanide. In the examples the following compounds are prepared: 5:5-(31-methylcyclohexamethylene) - and 5:5 - (21 - methylcyclohexamethylene)-hydantoin and 2-thiohydantoin. Dithiohydantoin compounds of the general formula <FORM:0807678/IV (b)/4> wherein R1 and R2 have the above significance, are prepared by the sulphurization of the corresponding hydantoins, e.g. by heating with phosphorus pentasulphide in an inert solvent such as tetrahydronaphthalene, or by heating 3-methyl- or 4-methyl-cycloheptanone, sodium cyanide, ammonium chloride and carbon disulphide in the presence of an inert diluent or solvent such as aqueous methanol. The preparation of 5:5 - (31 - methylcyclohexamethylene)-and 5:5 - (21 - methylcyclohexamethylene)-2:4-dithiohydantoin is detailed. 1-Amino-1-cyano - 4 - methylcycloheptane hydrochloride is obtained by reacting 4-methylcycloheptan-1-one, potassium cyanide and ammonium chloride in water and ethanol, to form the desired free base which is then treated with hydrogen chloride.