Pyridine-4-aldehyde thiosemicarbazone

An extensive presentation of biological data produced by a total of 33 pyridine aldehyde thiosemicarbazones has been described [32]. This report also included data on 26 isoquinoline carboxaldehyde thiosemicarbazones and 45 other heterocyclic aldehyde thiosemicarbazones. However, no attempt was made to correlate structure with activity. Recently, a series of 5-substituted analogues of (4) has been reported [33] which included various esters of 5-hydroxymethyl-pyridine thiosemicarbazone. 5-Acetoxymethyl (57b) and 5-isonicotinoyl (570 derivatives were found to be active antineoplastic agents. The acetoxymethyl derivative (57b) was markedly active against the Ehrlich ascites carcinoma, leukemia L-1210, and leukemia C-1498, while moderately effective against Nakahara-Fukuoka sarcoma and inactive against adenocarcinoma 755. The iso-... 

Horse heart cytochrome c (Sigma, type VI) was purified by chromatography on a Whatman CM-32 column at 4 C as described previously 24 according to the literatures 28 Pyridine aldehyde thiosemicarbazones (PATS) and benzaldehyde thiosemicarbazone (BATS) were synthesized from thiosemicarbazide and corresponding aldehydes , and recrystallized from ethanol. All other reagents were of analytical grade, and used as received. 

Virus replication comprises numerous biochemieal transformations that might provide suitable targets for antiviral therapy. The antiviral effect of thiosemicarbazones was first demonstrated by Hamre et al. [53, 54], who showed that p-aminobenzaldehyde-3-thiosemicarbazone and several of its derivatives were active against vaccinia virus in mice. These studies were extended to include thiosemicarbazones of isatin, benzene, thiophene, pyridine, and quinoline derivatives, which also showed activity against vaccinia-induced encephalitis. The nature of the aldehyde/ketone moiety was not as significant as the presence of the thiosemicarbazide side chain the latter was deemed essential for antiviral activity. 

Another study of an active antineoplastic agent, 2-formyl-4-morpholino-pyridine thiosemicarbazone (107), revealed that the conformation of the molecule is similar to that observed with other related thiosemicarbazone derivatives [51]. Comparison of these molecular structures indicates that the rotational barrier about the 2-carbon of the pyridine ring and the aldehydic carbon, which is influenced by the dihedral angle of this bond, may be important for the antineoplastic activity of this class of agents. 

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