(a) 200 g of 2-hydroxy-4-chlorobenzoic acid and 1 liter of methanol are
brought to reflux. Dry hydrogen chloride gas is bubbled through the mixture
during a time period of 8 hours. The excess of methanol is evaporated, the
residue is poured into cold water, neutralized and extracted with ether. After
evaporation of the solvent the product is distilled under vacuum. The boiling
point of the compound at 15 mm Hg is 127°C, and the yield is 85% of the
theoretical.
(b) The production of 2-allyloxy-4-chloromethyl benzoate:
4-Chloro-2-hydroxymethyl benzoate 186 g (1 mole), 152 g anhydrous
potassium carbonate, 133 g redistilled allyl bromide in 350 ml acetone are
heated of refluxing under agitation. At the end of 6 hours the reaction is
completed. The reaction mixture is filtered for removal of the mineral salts.
The acetone is evaporated. There is thus obtained an oily residue, which
rapidly crystallizes. After recrystallization from methanol the obtained product
is a white crystal solid, which melts at 56°C. The yield is 84%.
(c) The production of 2-allyl-oxy-4-chlorobenzoyl chloride:
The 2-allyloxy-4-chloromethyl benzoate obtained under (b) above is saponified
under the usual conditions on for obtaining the corresponding acid, and the
corresponding acid is obtained in a yield of 91%, the acid melting at 87°C.
The chloride of the acid is prepared by treating 1 mol of the acid with 1.5
moles of thionyl chloride (freshly rectified on linseed oil) in the presence of
benzene. There is thus obtained a pale yellow viscous liquid, which can be
further used without preliminary distillation.
(d) Preparation of the amide and of the hydrochloride:
115.5 g (0.5 mol) of the benzoyl chloride produced under (c) above is
dissolved in 500 ml of anhydrous chloroform. There is added to this solution
drop by drop while agitating and under cooling in an ice bath 116 g of β-
diethylaminoethylamine. After the addition is completed the agitation is
continued for 1 hour at ambient temperature. The reaction mass is then
washed with water, the chloroform is evaporated, the residue is taken up the
minimum of absolute alcohol, and there is then added a slight excess of
absolute alcohol saturated with hydrogen chloride. The hydrochloride
crystallizes by the addition of anhydrous ether. After recrystallization in
absolute alcohol plus ether there is obtained white crystals, which are soluble
in water and in alcohol. The 2-allyloxy-4-chloro-N-(β-
diethylaminoethyl)benzamide hydrochloride melts at 125°-127°C.
