The Infrared Spectra of 4-Substituted-Thiosemicarbazides and Diazotization Products

Lieber, Eugene; Rao, C. N. R.; Pillai, C. N.; Ramachandran, J.; Hites, Ralph D.

doi:10.1139/v58-118

Cited by 71 publications

(12 citation statements)

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“…A strong band near 1600-1640 cm Ϫ1 corresponds to -NH 2 bending vibration and a band at 1370-1400 cm Ϫ1 corresponds to CϭS stretching vibration. 25) On complexation both the -NH 2 bending and CϭS stretching vibrations were changed. These observations clearly indicate the participation of the NH 2 group and thiocarbonyl sulfur in coordination to the metal ion.…”

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confidence: 99%

Synthesis, Anticancer and Antibacterial Activity of Some Novel Mononuclear Ru(II) Complexes

et al. 2004

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The success of cisplatin and related platinum complexes as anticancer agents has stimulated a search for other active transition metal complexes, and ruthenium in particular has attracted the researchers.1) Metal complexes of ruthenium containing nitrogen and oxygen donor ligands are found to be effective catalysts for oxidation, reduction, hydrolysis and other organic transformation.2) The coordination environment around ruthenium plays the key role in stabilizing its different oxidation states and hence dictates the redox properties of the control atoms. (areneϭp-cymene, hexamethylbenzene and lϭcarbene or nitrogen containing heterocycles) have been tested for antibacterial and antifungal activity.The tris chelates of the ruthenium with bidentate ligands show intercalate properties with the DNA 13) and bind to Fe(III) sites of the proteins lactoferin and transferrin 14,15) and transferrin is thought to be responsible for the delivery of Ru(III) to cancer cells where it is taken up via receptor mediated endocytosis.16) Transferrin normally transports Fe(III) in the blood but is only about one third occupied by Fe(III), and so there are vacant sites available for Ru(III) binding. Another important step in the mechanism of action of Ru(III) complexes is thought to be in vivo reduction to Ru(II), 17) which is kinetically more reactive than Ru(III). Recently we have reported, N-alkyl and N-aryl substituted thiosemicarbazide complexes with Ru(bpy) 2 Cl 2 and greater antibacterial activity was found in the N-alkyl substituted complexes whereas N-aryl substituted exhibited more antitumor activity.18) In view of the above facts we have investigated the design of a novel range of Ru(II) complexes and the structural features as well as the contribution of the ligands that are responsible for antitumor and antibacterial activity. Results and DiscussionChemistry The ligands nmit (nmitϭN-methyl-isatin-3-thiosemicarbazone) and icpl (icplϭisatin-3-(4-chlorophenyl) thiosemicarbazone) were prepared by reacting Nmethylisatin and isatin with thiosemicarbazide and 4-chlorophenyl thiosemicarbazide in alcohol in presence of glacial acetic acid in 1 : 1 molar ratios respectively. Other ligands like r-tsc (r-tscϭ4-substituted thiosemicarbazides) were prepared according to the literature 19,20) with slight modification (Chart 1). All these ligands were confirmed for their purity by their melting point, elemental analysis and infrared spectra.Ruthenium metal complexes with the ligands nmit, icpl, aze (azeϭacetazolamide) and r-tsc were prepared by the reaction of a stoichiometric quantity of Ru(phen) 2 Cl 2 / Ru(bpy) 2 Cl 2 with the respective ligands in alcohol in presence of nitrogen (Chart 2). The completion of the reaction was monitored by TLC on silica gel.The structures of these ligands, especially nmit, icpl and rtsc in Fig. 1, show that in no case these ligands can exhibit tridentate behavior. There are very few cases in which the thiosemicarbazides act as monodentate ligands binding to the metal centre through the sulfur atom, th...

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Synthesis, Anticancer and Antibacterial Activity of Some Novel Mononuclear Ru(II) Complexes

et al. 2004

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“…Smith and Kenny (7) have also arrived a t a similar conclusion. Thiohydrazides show no SH stretching absorption in the infrared spectra, but exhibit the characteristic --N-C=S bands (17) in the regions 1515-1495, 1325-1300, and I 1050-1010 crn-l. ~~~a r e n t l y there is no thione-thiol tautornerisrn in these derivatives in the solid state just as in the case of thiosernicarbazides (3). Thiohydrazides exhibit the characteristic frequencies due to the hydrazino group (3,18,19) in the regions 1600-1585, 1250-1190, 993-930, and 840-710 cnl-l.…”

Section: Thermal Decomposition Studiesmentioning

confidence: 92%

“…For personal use only. characteristic azide stretching frequencies (12), but exhibit the thiatriazole frequencies (3,5) in the regions 1615-1515, 1300-1270, 1120-1100, and 1080-1030 cm-I. Thus, the acyclic azide structure (V) for thioacyl azides, suggested by Oliveri-Mandala (13), must be eliminated from consideration.…”

Section: Thermal Decomposition Studiesmentioning

confidence: 99%

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5-Aryl- And 5-Alkyl-1,2,3,4-Thiatriazoles: Synthetic, Spectroscopic, and Degradative Studies

Lieber¹,

Rao²,

Orlowski³

1963

Can. J. Chem.

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A number of 5-(p-substituted)phenyl-1,2,3,4-thiatrizoes have been synthesized by the diazotization of p-substituted thiobenzhydrazides or by the reaction of sodium thiobenzoylthioglycollates with sodium azide. The thermal decomposition of these thiatriazoles yields nitriles, nitrogen, and sulphur. 5-Alkyl-1,2,3,4-thiatriazoles are very unstable and readily decompose to nitriles. Infrared and ultraviolet absorption spectra of 5-(p-substituted)phenyl-1,2,3,4-thiatriazoles have been studied. Infrared spectra of several thiohydrazides have also been studied and there appears t o be no thiol-thione tautomerism in these derivatives. The thiatriazole ring is found to be electron withdrawing. ISTRODUCTIONThe existence of the 1,2,3,4-thiatriazole system was firmly established by Lieber and co-workers (1-5). I t has been shown that the diazotization of 4-substituted thiosemicarbazides, as well as the reaction of alkyl-and aryl-isothiocyanates with hydrazoic acid, leads to 5-(substituted)amino-1,2,3,4-thiatriazoles (1, 2). The reaction product of azide ion with carbon disulphide has been shown to possess the 1,2,3,4-thiatriazoline-5-thione structure and not the acyclic azidodithiocarbonic acid structure (4). The esters of the so-called azidodithiocarbonic acid have been found to be either 5-substituted mercapto-1,2,3,4-thiatriazoles or 4-substituted-1,2,3,4-thiatriazoline-5-thiones (5). In the present communication, we report the synthesis of 5-alkyl-and 5-(substituted)phenyl-1,2,3,4-thiatriazoles (I) by two independent methods.* We have also investigated thethermal decomposition and infrared and near-ultraviolet absorption spectra of these thiatriazoles (I). In addition, we have studied the infrared spectra of 4-(substituted)-thiobenzhydrazides and aliphatic thiohydrazides.

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“…Depending on the substituent, substituted tetrazoles can undergo several forms of tautomerism: apart from the ring-opening within the azido-imine-tautomerism, C5-alkyl or unsubstituted rings undergo changes in the substitution pattern via annular-tautomerism [2], whereas an electronegative substituent in the C5-position favours amino-imino-tautomerism [3]. …”

Section: Introductionmentioning

confidence: 99%

Microwave alkylation of lithium tetrazolate

2016

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N1-substituted tetrazoles are interesting ligands in transition metal coordination chemistry, especially in the field of spin crossover. Their synthesis is performed in most cases according to the Franke-synthesis, using a primary amine as reagent introducing the substitution pattern. To enhance flexibility in means of substrate scope, we developed a new protocol based on alkylation of lithium tetrazolate with alkyl bromides. The N1–N2 isomerism of the tetrazole during the alkylation was successfully suppressed by use of highly pure lithium tetrazolate and 30 vol.% aqueous ethanol as solvent, leading to pure N1-substituted products. The feasibility of this reaction was demonstrated by a selection of different substrates.Graphical abstract

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The Infrared Spectra of 4-Substituted-Thiosemicarbazides and Diazotization Products

Cited by 71 publications

References 9 publications

Synthesis, Anticancer and Antibacterial Activity of Some Novel Mononuclear Ru(II) Complexes

Synthesis, Anticancer and Antibacterial Activity of Some Novel Mononuclear Ru(II) Complexes

5-Aryl- And 5-Alkyl-1,2,3,4-Thiatriazoles: Synthetic, Spectroscopic, and Degradative Studies

Microwave alkylation of lithium tetrazolate

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