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Benzo[b][1,4]oxazines have been synthesized in good to excellent yields in the presence of the ionic liquid 1-butyl-3-methylimidazolium bromide [bmim]Br under relatively mild conditions without any added catalyst, The method offers the advantages of good yields and short reaction times, and the ionic liquid can be easily separated from the product and reused. [ABSTRACT FROM AUTHOR]

Aromatic aldehydes have been successfully converted into their corresponding dithioacetal, dithiolane and dithiane derivatives in excellent yields with thiol (benzyl thiol and thiophenol), 1,2-ethanedithiol and 1,3-propanedithiol using trichloroacetic acid in sodium dodecyl sulfate micelles. The same procedure is applicable to ketones, but they need more time to be converted into their thioacetals. [image omitted] [ABSTRACT FROM AUTHOR]

A quaternary ammonium hydroxide-type of anion exchange resin (Amberlite IRA-400) was found to be an effective and reusable catalyst for the synthesis of various 4H-benzo[b]pyran derivatives via a one-pot, three-component condensation in aqueous media. Short reaction time, easy and quick isolation of the products, environmentally friendly procedure, excellent chemoselectivity, and excellent yields are the main advantages of this procedure. [ABSTRACT FROM AUTHOR]

Selective oxidation of sulfides to sulfoxides is achieved by H2O2 using HNO3 as the promotor. Aromatic and aliphatic sulfides are oxidized to sulfoxides in excellent yields and short reaction times. Different functional groups including C-C double bond, ester, ketone, acetal, alcohol, and oxime groups are tolerated under this reaction condition. [ABSTRACT FROM AUTHOR]

Various types of sulfides are selectively oxidized to sulfoxides in excellent yields using 30% aqueous hydrogen peroxide as an oxidant in the presence of POCl3 in ethanol at 50 °C. It is noteworthy that functional groups remain unaffected and only the sulfur atom is selectively oxidized. [ABSTRACT FROM AUTHOR]

Oxidative coupling of thiols to the corresponding symmetrical disulfides was performed in the presence ofγ-picolinium chlorochromate and its silica gel supported. The reactivity of silica gel supportedγ-picolinium chlorochromate for thiophenol derivatives is more than the reactivity of pyridinium andγ-picolinium chlorochromates. [ABSTRACT FROM AUTHOR]

Bismuth nitrate pentahydrate catalyzes the three component condensation reaction of an aromatic aldehyde, urea and a β-ketoester or a β-diketone under solvent-free conditions to afford the corresponding dihydropyrimidinones (DHPMs) in high yields. The present method is also effective for the selective condensation of aryl aldehydes in the presence of aliphatic aldehydes. [ABSTRACT FROM AUTHOR]