Abstract:We describe here an efficient and regioselective synthesis of arylselanyl anilines by coppercatalyzed direct arylselenation of arylamines. Using a catalytic amount of copper iodide in dimethyl sulfoxide at 110 8C under an air atmosphere, a range of arylselanyl anilines was obtained directly from substituted diaryl diselenides in moderate to good yields via C À H bond cleavage of aryl amines.

We described herein our results on the silver-catalyzed synthesis of diaryl selenides via a cross-coupling reaction of diaryl diselenides with aryl boronic acids. The methodology is tolerant to electron-donor and electron-withdrawing groups at the substrates and the desired products were obtained in good to excellent yields.

We described herein the use of imidazolium ionic liquids [bmim]PF 6 and [bmim]BF 4 in the selective, metal and catalyst-free synthesis of unsymmetrical diaryl selenides by electrophilic substitution in arylboron reagents with arylselenium halides (Cl and Br) at room temperature. This is a general substitution reaction and it was performed with arylboronic acids or potassium aryltrifluoroborates bearing electron-withdrawing or electron-donating groups, affording the corresponding diaryl selenides in good to excellent yields. The ionic liquid [bmim] [PF 6 ] was easily recovered and utilized for further substitution reactions.

Bis-arylsulfenyl- and bis-arylselanyl-benzo-2,1,3-thiadiazoles were synthesized in good yields by copper-catalysed cross-coupling reaction of arylthiols or diaryl diselenides with the commercially available 4,7-dibromobenzo[c][1,2,5]thiadiazole.

Palavras-chave: adubo nitrogenado, ureia, eficiência do fertilizante, volatilização de amônia, N-(nbutil) triamida tiofosfórica. ABSTRACT Urea is the main nitrogen source used in flooded rice fields, but it is prone to ammonia volatilization losses. The use of N-(n-butyl) thiophosphoric triamide (NBPT) urease inhibitor, as urea additive, can reduce this inconvenient, inhibiting temporarily urea enzymatic degradation. An experiment was carried out on a Planossolo Háplico (Albaqualf), from October 2004 to April 2005, in Capão do Leão, RS, Brazil, to

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We described here an alternative method for the selective synthesis of mono‐ or bis‐selanyl alkenes. This method involves reactions of terminal alkynes with organylselenols, generated in situ by the reaction of diorganyl diselenides with H3PO2. These reactions proceeded efficiently at 90 °C under N2 atmosphere and are suitable to a range of diorganyl diselenides and terminal alkynes, both containing electron‐withdrawing and electron‐donating groups, affording the corresponding mono‐ or bis‐selanyl alkenes in good yields and selectively. When the reactions were performed using 5.0 equiv. of H3PO2 (0.5 mL; 50 wt% in H2O), mono‐selanyl alkenes were formed in good yields, whereas reactions carried out with additional H2O as the solvent (3.0 mL/mmol) provided bis‐selanyl alkenes in high yields. Additionally, the solvent/reducing agent system (H2O/H3PO2) could be recovered and directly reused for further reactions to synthesize bis‐selanyl alkenes.