A novel carbon tetrabromide promoted one-pot reaction of amines and carbon disulfide under mild conditions has been developed, which provides a straightforward and efficient access to thioureas and thiuram disufides, depending on the nature of the amines employed. The promotion effect is explained as the transient formation of a sulfenyl bromide intermediate from dithiocarbamate and carbon tetrabromide during the reaction.

A simple and efficient AlCl(3)-mediated C-C coupling reaction between readily available alpha-hydroxyketene-S,S-acetals and various arenes via direct substitution of the hydroxy group in alcohols has been developed. On the basis of this C-C coupling reaction, a series of bio- and pharmacologically important 3,4-disubstituted dihydrocoumarins, difficult to obtain by other methods, were prepared in high yields by a sequential Friedel-Crafts alkylation and intramolecular annulation reaction of alpha-hydroxyketene acyclic-S,S-acetals with phenols under mild conditions.

A novel and efficient route to 4-halogenated N-substituted 2(1H)-pyridinones has been developed via a one-pot domino process of readily available alpha-acetyl-alpha-carbamoyl ketene dithioacetals with Vilsmeier reagents. These 4-halogenated-2(1H)-pyridinones constitute useful intermediates due to the easy elaboration on either the pyridinone core (by the displacement of the halogen atom) or functionality transformation (dithiocarbonyl functionality) and have proven to be a useful synthetic scaffold in the synthesis of the bio- and pharmacologically important fused-ring diazepine core.

2008 C-C bond formation O 0282AlCl3-Mediated Direct Carbon-Carbon Bond-Forming Reaction of α-Hydroxyketene-S,S-acetals with Arenes and Synthesis of 3,4-Disubstituted Dihydrocoumarin Derivatives. -In the presence of AlCl3 α-hydroxyketeneacetals efficiently react with arenes to afford products of type (III) and (VI). Coupling of the acyclic acetals (VII), (XI), and (XIV) with phenols and naphthols allows facile access to 3,4-substituted dihydrocoumarins and chromene derivatives. -(PIAO, C.-R.; ZHAO*, Y.-L.; HAN, X.-D.; LIU, Q.; J.

Synthesis of 4-Halogenated 2(1H)-Pyridinones. -The target compounds are useful synthons which can easily be transformed into biologically important diazepines such as (XI) and some other products. Starting from dithioacetals of type (IV), diones are formed instead of the expected halogenated pyridinones. -(CHEN, L.; ZHAO*, Y.-L.; LIU, Q.; CHENG, C.; PIAO, C.-R.; J. Org. Chem. 72 (2007) 24, 9259-9263; Dep. Chem., Northeast Norm. Univ., Changchun 130024, Peop. Rep. China; Eng.) -Jannicke 15-138