GB796069A - Substituted hydantoins - Google Patents

Abstract

The invention comprises substituted hydantoins of the general formula <FORM:0796069/IV (b)/1> wherein R1 and R2 represent hydrogen or methyl, ethyl or aryl radicals, and one of R3 and R4 represents hydrogen and the other a methyl or ethyl radical, and the preparation thereof in the case where R3 represents hydrol gen and R4 represents a methyl or ethyradical by alkylating hydontoin compounds of the general formula <FORM:0796069/IV (b)/2> wherein R1 and R2 have the above significance and in the case where R3 represents a methyl or ethyl radical and R4 represents hydrogen by reacting an hydrindene compound of the general formula <FORM:0796069/IV (b)/3> wherein R1 and R2 have the above significance and R3 represents a methyl or ethyl radical, and cyanic acid and hydrolysing the product in an acid medium, e.g. aqueous mineral acid such as aqueous hydrochloric acid. The latter process may be modified in that the hydrindene reactant is prepared by reacting the correponding a -hydrindone cyanohydrin and methylamine or ethylamine, e.g. a -hydrindone cyanohydrin itself may be reacted with methylamine. The alkylation step in the first process referred to above may be carried out with an alkyl sulphate, e.g. dimethyl sulphate, preferably in the presence of an aqueous or aqueous alcoholic alkaline medium such as aqueous alcoholic sodium hydroxide, or an alkyl halide, e.g. methyl or ethyl iodide, preferably in an alcoholic medium containing an alkali metal alkoxide such as an ethanolic metium containing sodium ethoxide. The latter process may also be modified in that the hydantoin reactant may be used in the form of a salt thereof such as the hydrochloride salt, and the cyanic acid is then used in the form of an alkali metal cyanate such as sodium cyanate. In the examples, 31-methylspirohydrindenyl - [1 : 51] - hydantoin, and the corresponding 1-methyl-, 31-ethyl-3 : 31-dimethyl-, 2 : 31-dimethyl- and 3-phenyl-31-methyl-compounds are prepared. Starting compounds. a -Hydrindone cyanohydrins of the general formula <FORM:0796069/IV (b)/4> wherein R1 and R2 have the above significance, are prepared by reacting the required a -hydrindone and hydrogen cyanaide or an alkali metal cyanide, e.g. sodium cyanide, in an aqueous medium. 2-Methylspirohydrindenyl-[1 : 51]-hydantoin is prepared by reacting 2-methyl-a -hydrindone, potassium cyanide and ammonium carbonate in aqueous ethanol, followed by acidification. 3-Phenylspirohydrindenyl-[1 : 51]-hydantoin is prepared by a similar method.