2-Thiophenecarbonyl chloride

Reduction of 1-adamantanecarbonyl chloride at carbon or mercury leads to the quantitative formation of 1-adamantanecarboxaldehyde [80]. Mubarak [81] investigated the reduction of 2-thiophenecarbonyl chloride at both carbon and mercury the starting material appears to undergo a two-electron reduction to form an acyl anion, which leads to l,2-di(2-thienyl)ethene-l,2-diol di(2-thiophenecarboxylate) as the major product and to 2-thiophenecarboxaldehyde as the minor product. 

Thiophenecarbonyl chloride is used as intermediate in the synthesis of many pharmaceuticals. For example, its condensation with protected L-4-hydroxyproline followed by deprotection gives a product claimed as antiinflammatory and antidystrophic agent (Ref. 16). 

Fu and Shuttleworth (03TL3843) (Scheme 14) set out to develop conditions for A -acylating 5-aminopyrazol-3-ones used in previous years as building blocks in the construction of 6,5-fused heterocycles. The simple reaction of 5-aminopyrazol-3-one 51 with 2-thiophenecarbonyl chloride 52 in DMF in the presence of polymer-supported Hunig s base 53, however, turn out to be extremely capricious. Under... 

Thiophene 2-Thiopheneaceticacid 2-Thiopheneacetonitrile 2-Thiophenecarbonitrile 3-Thiophenecarbonitrile 2-Thiophenecarbonyl chloride... 

Friedel-Crafts reaction of phosgene with heterocyclic aromatic compounds is also difficult to stop at the acid chloride stage. However, under selected conditions, heteroaromatics such as thiophene can be directly acylated to give thiophenecarbonyl chloride [Scheme T9] (Ref. 15) ... 

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