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Different thiosemicarbazone derivatives react with dimethyl acetylene dicarboxylate (DMAD) and diethyl acetylene dicarboxylate (DEAD) by three different methods: a) in ethyl acetate solvent at ambient temperature, b) one-pot synthesis under microwave irradiation and solventfree conditions (three-component reaction between thiosemicarbazide, aldehyde/ ketone and DMAD or DEAD), c) a microwave-assisted synthesis under solvent-free conditions, to obtain five-membered S,N-heterocycles thiazolines in good to excellent yields.

Some pentafluoropyridine derivatives have been synthesized by the reaction of pentafluoropyridine with appropriate mono and bidentate nucleophile under ultrasonic irradiation. This new methodology provides good to excellent yields in short reaction times (25-120 min) at room temperature.

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A new reagent 2-(2,3-dihydroxy-4-oxocyclobut-2-enylidene) hydrozinecarbothiamide has been synthesized and used for developing a simple spectrophotometric method for the determination of Fe(III) which is based on a 2 : 1 complex formation between Fe(III) and new reagent in aqueous solution. e method is optimized in terms of the pH value, amount of reagent required, ionic strength, and stability of the complex, sensitivity, linearity, and tolerance limits of various foreign ions. e complex is a redbrown chelate, with max = 465 nm at pH = 3 (= 5 3 L⋅mol − ⋅cm −). e ionic strength was kept constant at 0.02 by adding appropriate amounts of NaCl solution. e calibration curve is linear in the concentration range from 0.27-33.50 g⋅mL −. e effects of foreign ions on the determination of Fe(III) were investigated in order to assess the selectivity of the method. e method was applied in determination of Fe(III) in tap water, cow milk, and human serum.

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