intermediates heterocyclic Halide chemicals cyan chemicals boronic chemicals sulfon chemicals

A method for bromo-and iododifluoromethylation of aldehydes using bromo- and iodo-substituted difluoromethyl silicon reagents is described. The reaction is performed in the presence of a combination of tetrabutylammonium and lithium salts Bu4NX LiX X;Br or I in propionitrile. It is believed that, in this process, a short-lived halodifluoromethyl carbanion serves as nucleophile, which is reversibly generated from difluorocarbene and a halide anion.
An efficient synthesis of sulfonyl carbamates and sulfonyl ureas from sulfonyl azides employing a palladium-catalyzed carbonylation protocol has been developed. Using a two-chamber system, sulfonyl azides, PdCl2, and CO gas, released ex situ from Mo(CO)6, were assembled to generate sulfonyl isocyanates in situ, and alcohols and aryl amines were exploited as nucleophiles to afford a broad range of sulfonyl carbamates and sulfonyl ureas. A protocol for the direct formation of substituted sulfonamides from sulfonyl azides and amines via nucleophilic substitution was also developed.
Heteroaromatic thiols may be oxidized to the sulfonyl chloride at low temperature by using 3.3 equiv of aqueous sodium hypochlorite. The reaction is rapid, avoids the use of chlorine gas, and succeeds with substrates that have previously been found to afford little or none of the sulfonamide product with other procedures. The method allows the preparation of the sulfonyl fluorides, which are stable enough to be purified and stored, making them potentially useful monomers in parallel chemistry efforts.
A new transition-metal-free amination of pyridine-2-sulfonyl chloride and related N-heterocycles using magnesium amides of type R2NMgCl.LiCl is reported. Additionally, the directed ortho-magnesiation of pyridine-2-sulfonamides using TMPMgCl.LiCl was investigated. Reaction of the magnesium intermediates with various electrophiles and subsequent amination using magnesium amides led to a range of 2,3-functionalized pyridines. Also, cyclization reactions providing an aza-indole and an aza-carbazole were carried out.
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