Several workers have reported that formaldehyde reacts with 8-hydroxyquinoline in the presence of alkali, sulphuric acid or hydrochloric acid, and that the products obtained were carbinols or diquinolylmethancsl*.
A Swiss patent' describes the preparation of a derivative of 8-hydroxyquinoline by saturating a mixture of formaldehydc and 8-hydroxyquinoline in hydrochloric acid solution, with hydrochloric acid gas. The conditions employed in this preparation are however the same as those used in chloromethylation reactions. The reaction between 8-hydroxyquinoline and formaldehyde in hydrochloric acid solution was therefore investigated in order to discover the reaction products formed under particular conditions, and to study the chelating properties of the substituted 8-hydroxyquinoline.
EXPERI hf ENTAL
Preparation of 7-chloromelhyl-8-hydroxygurnolinc hydvochloride
Formaldehyde (8 ml of a 37% solution) was added to a solution of 8-hydroxyquinoline in concentrated hydrochloric acid (7.3 g in 8 ml) and the resulting solution was saturated with hydrochloric acid gas for z to 3 hours. A bright yellow crystalline compound separated. Yield 609,. Calcd. for C,,H,NOCll: C, 52.20; H, 3.95; Found: C, 51.98; H, 3.95; decomposes above 283 l C. 8-Hydroxyquinaldine could also be chloromethylatcd under tho same conditions, and the product obtained was probably 7-chloromethyl-8-hydroxyquinaldme lrydrochlorlde. Yield 58%,. Calcd. for C,,H,,NOCl,: