Radioprotective action of thiadiazole derivatives
Continuing previous investigations on the search for radioprotectors among the sulfurcontaining heterocycles [i, 2], we synthesized and studied the radioprotective properties of derivatives of 1,3,4and 1,2,4-thiadiazoles with various substituents: amino groups, alkyls, and mercapto groups. The following thiadiazole derivatives were investigated: 2alkylamino-5-alkyl-l,3,4-thiadiazoles and their methiodides (I-VII); 2-alkylamino-l,3,4thiadiazole-5-thiones (VIII-XII); 2-alkylamino-5-alkylmercapto-l,3,4-thiadiazoles (XIIIXVIII); 2,5-diamino-l,3,4-thiadiazole and its methiodide (XIX, XX), and 1,2,4-thiadiazoles (XXI-XXIII).
Synthesis of New 1,3,4-Thiadiazole and 1,2,3,4-Oxathiadiazole Derivatives from Carbohydrate Precursors and Study of Their Effect on Tyrosinase Enzyme
5-(1,2,3,4-Tetrahydroxybutyl)-2-methylfuran-3-carbohydrazide (2) was condensed with a variety of ketones to afford carbohydrazide derivatives 3–6. Acetylation of 3–5 afforded the acetyl derivatives 7–9, while periodate oxidation of 3–6 afforded the formyl derivatives 10–13. Acid catalyzed condensation of thiosemicarbazide or o-tolylthiosemicarbazide with the prepared aldehydes 10–12 gave thiosemicarbazone derivatives 14–19. Cyclization of the latter with acetic anhydride afforded 4,5-dihydro-1,3,4-thiadiazolyl derivatives 20–25. On the other hand, condensation of p-tosylhydrazine with the prepared aldehydes 10–12 afforded p-tosylhydrazone derivatives 26–28. Cyclization of 26–28 with acetic anhydride afforded 1,2,3,4-oxathiadiazole derivatives 29–31 respectively. Moreover, the obtained results regarding to the effect of some of the prepared compounds on tyrosinase enzyme showed that the majority of these compounds having an inhibitory effect; especially compounds 12, 16, 17, and 28.
Luminescence Phenomena Involving Metal Enolates
1 
Introduction 
 
2 
Metal Enolates 
 
3 
Luminescence of Rare-Earth Enolates 
 
4 
Luminescence Involving s, p and d Metal Block Enolates 
 
5 
Applications 
 
6 
Acknowledgments 
 
 
 
Keywords: 
 
luminescence phenomena involving metal enolates; 
chemistry of metal β-diketonate complexes; 
luminescence of rare-earth enolates; 
photoluminescence of rare-earth β-diketonates; 
diketonate ligand–rare-earth ion energy transfer rates; 
luminescence involving s, p and d metal block enolates; 
photoluminescence of d-transition metal enolates; 
applications - time-resolved detection of luminescence for bioassays