Three new alternative synthetic strategies based on reactions of hydrazonoyl halides 3 with 2-methylthiouracil 2 and treatment of either 2-pyrimidinyl thiohydrazonates 8 or the diazonium coupling products of active (pyrimidin-2-ylthio)methylene compounds 12 with sodium ethoxide in ethanol are described for the title compounds. The mechanisms and regiochemistry of the studied reactions are discussed.
In this study, 2-N-arylimino-2,3-dihydro-1,3,4-thiadiazoles derivatives (6a-h) were synthetized. The mechanism of the studied reactions was discussed. The chemical structures of the compounds were elucidated by their IR, 1H-NMR, 13C-NMR, and Mass spectral data and elemental analyses. The compounds were tested for antimicrobial activity using diffusion agar technique.
The photochemical reactions of some azo derivatives of substituted pyrazolin-5one were examined. Irradiation of 4-arylazopyrazolin-5-one 1-3 gave the corresponding hydrazo derivatives 4-6 via reduction of the azo group and rearrangement of the pyrazolinone ring. The photo α-cleavage of (-CO-N-Ph) in the pyrazolinone ring is suggested leading to the formation of a diradical component followed by cyclization to give the final rearrangement products.Introduction: Diazopyrazole derivatives are known as versatile reagents that have been extensively utilized in synthetic heterocyclic chemistry [l-4]. A variety of pyrazolinone derivatives are known to exhibit analgesic and antiflammatory effect [5,6]. Continuation to our previous work aiming towards the synthesis of new substituted pyrazoles with expected pharmacological activity[7-10], it is of interest to study the photochemistry of the corresponding azo derivatives. Thus, when 2,3-dimethyl-l-phenyl-4-(2-hydroxynaphthyl-Brought to you by |
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