Patent GB-795107-A (GB)
Title: Improvements in or relating to cyclic dicyano and tetracyano compounds
IPC: C07D333/24
Filed: 1954-09-01
Abstract: The invention comprises cyclic di- or tetracyano compounds of formula: <FORM:0795107/IV (b)/1> wherein n is 1 or 2 and R is (1) a monocyclic aromatic radical which is substituted by one or more alkyl, phenolic hydroxy, aliphatic ester, cyano - alkyl, nitro - alkyl, carboxy - aliphatic, aralkyl or sulphoalkyl groups or a disubstituted monocyclic aromatic radical having two alkoxy groups or an alkoxy group and a halogen atom; (2) a heterocyclic radical with aromatic properties, having a 5- or 6-membered heterocyclic ring with not more than one oxygen or sulphur atom bridging carbon atoms in the ring or a substituted heterocyclic radical having the substituents defined above; or (3) a polynuclear aromatic radical which may be substituted with the substituents defined above, said R being free of aliphatic alcohol groups and nitrogen atoms excepting nitro and cyano groups attached to an aliphatic side chain.  The compounds are prepared by reacting a suitable aromatic or heterocyclic compound with 1 : 1-dicyanoethylene in the presence of an aluminium halide catalyst, preferably in the presence of a non-reactive diluent such as symtetrachloroethane, nitrobenzene and o-dichlorobenzene. Specified aromatic and heterocyclic compounds are toluene, xylenes, mesitylene, naphthalene, diphenyl, anthracene, phenanthrene, pyrene, chrysene, fluoranthrene, naphthacene, cyclohexylbenzene, tetrahydronaphthalene, benzocycloheptane, dibenzyl, tetraphenylmethane, pentacene, hexacene, furan, thiophene, thiophthene, thionaphthene, coumarone, 1 : 4-pyran and dibenzofuran. The cyano groups in the product may be hydrolysed to give dicarboxyethyl groups which can be decarboxylated to give monocarboxyethyl groups, e.g. 1 : 4 - dimethoxy - 2 : 5 - bis - (21 : 21-dicyanoethyl) benzene was hydrolysed to 1 : 4-dimethoxy - 2 : 5 - bis - (21 : 21 - dicarboxyethyl)-benzene which was decarboxylated to give 1 : 4-dimethoxy - 2 : 5 - bis - (21 - carboxyethyl)-benzene.  In examples: (1) toluene was reacted with 1 : 1-dicyano-ethylene using equimolar amounts in the presence of aluminium chloride and sym.-tetrachloroethane as diluent to give a mixture of ortho- and para-methylbenzylmalononitrile, the isomers were separated and the ortho-isomer was identified by hydrolysis, decarboxylation and oxidation to phthalic acid; (2) as in (1) m-xylene gave 2 : 4-dimethylbenzymalononitrile which was hydrolysed to 2 : 4-dimethylbenzylmalonic acid; (3) as in (1) 1-chloro - 4 - methoxybenzene gave 2 - methoxy -5-chlorobenzylmalononitrile, which was hydrolysed to 2-methoxy-5-chlorobenzylmalonic acid from which beta-(2-methoxy-5-chlorophenyl)-propionic acid was obtained by decarboxylation; (4) mesitylene and 1 : 1-dicyanoethylene in a molar ratio of 1 : 2 were reacted as in (1) to give 1 : 3 : 5-trimethyl-2 : 4-bis-(21 : 21-dicyanoethyl)-benzene which was hydrolysed to the corresponding acid; (5) as in (4) 1 : 4-dimethoxybenzene gave 1 : 4 - dimethoxy - 2 : 5 - bis (21 : 21 - dicyanoethyl)- benzene; (6) as in (1) 2 : 5 - dimethoxybenzylmalononitrile gave 1 : 4-dimethoxy - 2 : 5 - bis - (21 : 21 - dicyanoethyl)-benzene; (7) as in (1) furan gave 2-(21 : 21-dicyanoethyl)-furan, which was hydrolysed to alpha - furfuryl - malonic acid, which gave beta - (2 - furyl) - propionic acid on decarboxylation; (8) as in (4) dibenzyl gave p : p1 -(2 : 2 - dicyanoethyl) - dibenzyl which on hydrolysis gave p : p1 - (2 : 2 - dicarboxyethyl)-dibenzyl; (9) the following compounds were also obtained by the process of the invention, 2 : 4 : 6 - trimethylbenzylmalononitrile, 2 : 5-dimethylbenzylmalononitrile, 2 - naphthylmethylmalononitrile, 2 - thenylmalononitrile, 2 : 5 - dimethoxybenzylmalononitrile, p-hydroxybenzylmalononitrile, 1 - carboxymethyl - 3 - hydroxy - 4 - (21 : 21 - dicyanoethyl)-benzene, 1 - (b  - carboxyethyl) - 4 - (21 : 21 - dicyanoethyl) - benzene, 1 - (b  - phenylethyl) - 4-(21 : 21 - dicyanoethyl)- benzene, 1 - methyl - 2-(21 : 21 - dicyanoethyl) - 4 - nitromethyl - benzene, 4 - ethyl - 3 - (21 : 21 - dicyanoethyl)-phenylacetonitrile, 4 - (21 : 21 - dicyanoethyl)-benzyl acetate, 3 - (21 : 21 - dicyanoethyl) - 4-ethoxy - phenylmethanesulphonic acid, 4 - [p-(21 : 21 - dicyanoethyl) phenyl] - 3 - butenoic acid and 4 - [41 - (211 : 211 - dicyanoethyl)-naphthyl] - 3 - butenoic acid.