Hydrochloric Acid → 6,7-Dimethyl-1,4-di-cyanonaphthalene

Participants

Reaction Steps

17 parts of 4,5-dimethyl-1,2-bis-cyanomethyl-benzene and 7.8 parts of glyoxal hydrate (trimer) (3C2H2O2.2H2O) containing 80% of glyoxal to be liberated, are stirred in 100 parts by volume of methanol. The reaction mixture is treated at 0° to 5° C, with stirring and under nitrogen, with 10.5 parts of powdered potassium hydroxide added by small amounts. After the addition of potassium hydroxide, stirring is continued for a further 5 hours at 0° to 5° C under nitrogen. The slightly brown coloured reaction mixture is subsequently neutralised with dilute hydrochloric acid, freed from methanol in vacuo and extracted with methylene chloride. The methylene chloride extract is washed neutral with water, dried over sodium sulphate and concentrated to dryness in vacuo. Yield: 18 parts of a brown oil which is chromatographed over aluminium oxide. Elution with chlorobenzene yields 6.5 parts (34% of theory) of 6,7-dimethyl-1,4-di-cyanonaphthalene of formula ##STR46## in the form of white crystals with a melting point of 212°-220° C. Two recrystallisations from alcohol yield small white needles with a melting point of 225°-227° C.

Provenance & Evidence