Structural, Spectral, Biological and Electrochemical Studies Of Some ...

(Hexahydroazepine-4-thiocarboxylic acid 2-[1-(2-pyridinyl) ethylidene] hydrazide),
HL4A
The O-N-S donor ligands that we synthesized were,
4) Salicylaldehyde 4N -pyrrolidine thiosemicarbazone
(N-Pyrrolidine-2- [1-(2-hydroxy) benzylidine] hydrazine carbothioamide), H2SAP
5)2-Hydroxyacetopheone 4N -pyrrolidine thiosemicarbazone
(N-Pyrrolidine [1-(2- hydroxy methyl' benzylidine] hydrazine carbothioamide),
H2APP
2.3 Experimental techniques
Followings are some of the general experimental methods for the synthesis of
thiosemicarbazones.
Method-I. It involves the condensation of thiosemicarbazide with appropriate
simple or substituted carbonyl compounds.
Method-2. It involves replacement of the S-methyl group of the compound
formed from the condensation of a carbonyl compound with methyl hydrazine
carbodithioate by an appropriate amine; the rate of transamination depends on the
basicity of the amine.
Method-3. It involves a condensation between a carbonyl compound and
isothiocyanate.
Method-4. Holmberg and Psilanderhielm originally reported it and later refined
by J. P. Scovill [3]. In this, carboxymethyl -N-methyl -N-Phenyl dithiocarbamate
formed by the reaction between carbon disulphide, N-methylaniline, sodium
hydroxide and sodium chloroacetate is treated with hydrazine hydrate to get N­
methyl -N-phenyl thiosemicarbazide. It is then condensed with an appropriate
carbonyl compound and then transaminated with a suitable amine into desired
thiosemicarbazones. Using a suitable solvent both condensation and transamination
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