Patent GB-868786-A (GB)
Title: Cyclic triaza and tetra-aza compounds and light-sensitive silver halide emulsions containing them
IPC: C07D513/04
Filed: 1957-10-21
Abstract: The invention comprises compounds having the general formula: <FORM:0868786/IV (b)/1> wherein D completes a benzene nucleus, Q is -N= or -CR= (R being H, OH or substituted or unsubstituted alkyl or aryl), and X is S, Se or -NH-, except that it cannot be -NH- when Q is -N= ; and, when Q is -CR=, quaternary alkyl salts of such compounds.  The benzene ring completed by D may carry methyl, ethyl, chloro, bromo, hydroxyl, methoxy, ethoxy or amino substituents. Compounds wherein Q is -CR= and R is H or an alkyl group of 1-3 carbon atoms are prepared by condensing a compound of formula: <FORM:0868786/IV (b)/2> with an ortho ester RC(OR2)3 where R2 is methyl or ethyl, by refluxing e.g. in xylene and removing the alcohol formed with a fractionating column until the theoretical amount (3 mole) has been removed.  Thus 2-hydrazinobenzthiazole is refluxed with ethyl orthoformate or ethyl orthoacetate with or without xylene solvent, to give 8-thio-1 : 2 : 3a-triazacyclopent[a]indene and its 3-methyl derivative respectively, and 2-hydrazinobenzimidazole is refluxed in xylene with ethyl orthoacetate to give 3-methyl-1 : 2 : 3a : 8-tetrazacyclopent[a]indene.  Similarly, 3-ethyl-8-thia1,2,3a-triazacyclopent[a]indene, 3-methyl and 3-ethyl-1,2,3a,8-tetrazacylopent[a]indene, 8-selena-1,2,3a-triazacyclopent[a]indene and its 3-methyl derivative are prepared.  Compounds wherein Q is -CR= and R is an alkyl group of 3 or more carbon atoms or a substituted alkyl group, e.g. an alkyl group substituted by a chlorine atom or a carboxy or hydroxy group, and including b -carboxyethyl and g -hydroxypropyl, are prepared by refluxing a compound of Formula II with a large excess of acid RCOOH to give an acyl hydrazine, and refluxing this with phenol to effect ring closure.  By this method, 3-n(or iso) propyl-8-thia-1,2,3a-triazacyclopent[a]indene is prepared.  By using 1 mole of a dicarboxylic acid and 2 mols of Compound II in this method, a symmetrical bis(azacyclopent[a]indenyl) alkane is formed. Thus 2-hydrazinobenzthiazole is refluxed with adipic acid in phenol to give 1,4-bis(8-thia-1,2,3a-triazacyclopent[a]indene-3-yl)butane. Compounds wherein Q is -CR= and R iso-hydroxyphenol are prepared by refluxing an o-hydroxyphenol ester with a hydrazine of Formula II, e.g. in 1,2,4-trichlorobenzene, and distilling off the water formed. By this method 3-(o-hydroxyphenyl)-, 3-(2-hydroxy-5-sulphophenyl)-, 3-(1-hydroxy-4-sulpho-2-naphthyl)-, or 3-(1-hydroxy-2-naphthyl)-8- thia-1,2,3atriazacyclopent[a] indene is prepared.  Compounds where Q is -CR= and R is -OH are prepared by refluxing a hydrazine of Formula II with an arylisocyanate in trichlorobenzene. 3-Hydroxy-8-thia-1,2,3a-triazacyclopent[a]indene or its keto form, is prepared by this method.  Compounds wherein Q is -CR= and R is aryl or substituted aryl are prepared by condensing a compound of formula: <FORM:0868786/IV (b)/3> with a compound RCONHNH2 in phenol, and preferably in the presence of sodium phenoxide.  Thus 2-chlorobenzthiazole, bezhydrazide and sodium phenoxide are refluxed in phenol to give 3-phenyl-8-thia-1,2,3a-triazacyclopent[a]indene. 3-(p-Methoxyphenyl)-8-thia-1,2,3a-triazacyclopent[a]indene is similarly prepared.  Compounds wherein Q is -N= are prepared by dissolving a hydrazine of Formula II in aqueous acetic acid, cooling and adding sodium nitrite. 8-Thia-1,2,3,3a-tetrazacyclopent [a]indene is prepared in this manner.  The quaternary alkyl salts of compounds of Formula I wherein Q is -CR= can be prepared by heating the compound with an alkyl salt such as methyl-p-toluene sulphonate, ethyl sulphate or methyl sulphate.  2-Chlorobenzselenazole is prepared by adding sulphur monochloride to 2-mercaptobenzselenazole. 2-Hydrazinobenzselenazole is prepared by heating 2-chlorobenzselenazole with hydrazine hydrate.  Specifications 742,219, 742,220, 742,221, 742,224, 783,021 and U.S.A. Specification 2,073,600 are referred to.