In this work new heterocyclic pyrazolin derivatives have been synthesized
from diazonium chloride salt of 4-aminobenzoic acid: firstly, Azo compounds
were prepared from the reaction of an ethanolic solution of sodium acetate and
calculated amount of active methylene compound namely, (ethyl acetoacetate)
obtain the corresponding hydrazono derivative (1). Secondly,
Cyclocondensation reaction of compound (1) with hydrazine hydrate (2) inboiling ethanol affording the corresponding pyrazoline-5-one. Then compound
(2) reacted with thionyl chloride to give the corresponding acid chloride
derivative(3), followed by conversion into the corresponding carboxylic acid
thiosemicarbazide (4), esters (7-9), thioesters (10), (11), and amides (12-14),
when treated hydrazine hydrate, thiosemicarbazide, alcohols, alkylthiol and
secondary amines in dry refluxing benzene; respectively. Furthermore, 1,2,4-
triazole heterocyclic ring, which might result in biologically active agents, have
been prepared by refluxing thiosemicarbazide derivative (4) with sodium
hydroxide solution (4%) followed acidification of the result using (10%)HCl
solution. Moreover, 1, 3, 4, - thiadiazole heterocyclic ring (6) has been prepared
by treatment of thiosemicarbazide derivative with concentrated sulfuric acid as
cyclization agent. Finally, derivative (15) has prepared by reflux (1) with phydroxybenzaldehyde
then the product reflux with 5-amino-1, 3, 4-thiadiazol-2-
thiol to product (16) derivative. All structures of newly synthesized compounds
have been characterized and identified via of their physical properties and
spectral data analysis (IR, UV.) |