Patent GB-854955-A (GB)
Title: A process for the production of symmetrical and unsymmetrical azo compounds
IPC: C07C245/10
Filed: 1957-11-20
Abstract: Symmetrical and unsymmetrical azo compounds are prepared by subjecting at least one organic compound containing at least one methylene and/or methine group, in the dissolved state to the action of an organic azide.  The azides are of formula RN3 wherein R may be an aliphatic, cycloaliphatic, aromatic, aralkyl, ester, heterocyclic, acyl or sulphonyl radical.  In a modification of the process, the product of the above process is an intermediate which may be disproportionated by heating to give an azo compound or may be further reacted with an organic compound containing a methylene and/or methine group to give an azo compound.  In the latter case, the azo compound may not contain the structure of the intermediate which may only contribute the azo nitrogen atoms to the final product.  In Examples: (1) a mixture of 1-phenyl-3-methyl-5-pyrazolone, piperidine and phenyl azide is heated, cooled, diluted with water, acidified with hydrochloric acid, the residue filtered off and recrystallised from glacial acetic acid to give a brick-red crystalline powder of probable formula: <FORM:0854955/IV(b)/1> and the following compounds; 1-(p-amino-phenyl)-3-methyl-5-pyrazolone, 1-phenyl-3-carboxy-5-pyrazolone, 1-pyridyl-(2')-5-pyrazolone, a - and b  naphthols, 2 : 3-hydroxynaphthoic acid anilide, -cyano-acetophenone, 1 : 3-di(cyanoacetyl)-5-stearoyl-aminobenzene (to give a pentakisazo compound), 1 : 3 : 3-trimethyl-2-methylene-indoline, 3-phenyl-isoxazolone and ethyl cyanoacetate are reacted similarly with benzene sulphonyl, dimethyl-aminosulphonyl, 1-carboxy-2-chlorobenzene-5-sulphonyl and methane sulphonyl azides; (2) diethyl malonate is reacted with methane sulphonyl azide to give a compound of formula: <FORM:0854955/IV(b)/2> which is reacted with 1-phenyl-3-methyl-5-pyrazolone to give the compound of formula (I) above; (3) the compound obtained by reacting anthrone with methane sulphonyl azide is heated to give 9-[101-hydroxy-anthracenylazo-(91) ]-10-hydroxy-anthracene, which passes with loss of nitrogen to 10 : 101-dihydroxy-9 : 91-bianthryl.  Dimethyl-aminosulphonyl azide is prepared by reacting dimethylamino-sulphochloride with sodium azide in aqueous acetone and steam distilling the oil which separates on adding water to the reaction mixture. 1-Carboxy-2-chlorobenzene-5-sulphonylazide is prepared by reacting 1-carboxy-2-chlorobenzene-5- sulphonyl chloride with sodium azide in aqueous methanolic sodium hydroxide and recovering the product by acidification and filtration.  Specification 800,262 is referred to.ALSO:Symmetrical and unsymmetrical azo compounds are prepared by subjecting at least one organic compound containing at least one methylene and/or methine group, in the dissolved state to the action of an organic azide.  The azides are of formula RN3 wherein R may be an aliphatic, cycloaliphatic, aromatic, aralkyl, ester, heterocyclic, acyl or sulphonyl radical.  In a modification of the process, the product of the above process is an intermediate which may be disproportionated by heating to give an azo compound or may be further reacted with an organic compound containing a methylene and/or methine group to give an azo compound.  In the latter case, the azo compound may not contain the structure of the intermediate which may only contribute the azo nitrogen atoms to the final product.  In Examples: (1) a mixture of 1-phenyl -3- methyl -5- pyrazolone, piperidine and phenyl azide is heated, cooled, diluted with water, acidified with hydrochloric acid, the residue filtered off and recrystallised from glacial acetic acid to give a brick-red crystalline powder of probable formula: (I) <FORM:0854955/IV (c)/1> and the following compounds: 1-(p-amino-phenyl) -3- methyl -5- pyrazolone, 1- phenyl -3-carboxy -5- pyrazolone, 1- pyridyl -(21)- 5- pyrazolone, a - and b -naphthols, 2 : 3- hydroxynaphthoic acid anilide, -cyanoacetophenone, 1 : 3- di(cyanoacetyl) -5- stearoylaminobenzone (to give a pentakisazo compound), 1 : 3 : 3-trimethyl -2- methyleneindoline, 3-phenyl-isoxazolone and ethyl cyanoacetate are reacted similarly with benzene sulphonyl, dimethyl-aminosulphonyl, 1- carboxy -2- chlorobenzene-5- sulphonyl and methane sulphonyl azides; (2) diethyl malonate is reacted with methane sulphonyl azide to give a compound of formula: <FORM:0854955/IV (c)/2> which is reacted with 1- phenyl -3- methyl -5-pyrazolone to give the compound of formula (I) above; (3) the compound obtained by reacting anthrone with methane sulphonyl azide is heated to give 9-[101- hydroxyanthracenylazo-(91) ]-10- hydroxyanthracene.  Specification 800,262 is referred to.