Carboxylic acids, amides prepared chlorination

Wallach was the first (1874) to report on the transformation of carboxylic acid amides to amide chlorides by treatment with PCls various types of amides were converted by this reagent to chloromethyleneiminium chlorides (30 equation lg). - > Side reactions can include the a-chlorination of the amide chloride. If excess PCIs is used, the formation of iminium salts with complex ions (31) has been reported. The very labile bromomethyleneiminium bromides (32 equation 19) can be obtained by action of PBrs on tertiary amides. The iodomethyleneiminium salt (33) was prepared from DMF and diphosphorus tetraiodide in CS . ... 

The acid chloride of phenothiazine-1-carboxylic acid has been prejDared by treating the acid with the calculated amount of PCI5 in benzene, thus avoiding ring chlorination -(see Section V, A, 1, d). Another way to prevent ring chlorination in this reaction is first to acylate at position 10. ° Some amides have been prepared from phenothiazine carboxylic acid chlorides - ° and Curtius degradations performed. ... 

Other carboranylporphyrins and boronated chlorine eg for PDT, in which porphyrin is linked to the carboranyl moiety via the boron or the carbon atoms have also been reported by OTshevskaya et al. In arecent work, boronated amide derivatives starting from 5,10,15,20-tetra(p-aminophenyl) porphyrin and 9-o- and 9-m-carborane carboxylic acid chlorides were prepared. Also, the reaction of 2-formyl-5,10,15,20-tetraphenylporphyrin with the lithium salt of 1,2-c/oso-C2BjoHj2, and... 

Many commercial sulfonylureas contain an ortho ester, therefore, preparation of tied-back ester was of great interest. We could use the target intermediate monomethylamide 2 (Scheme X), as both a directing group for metallation and as the latent lactone group. The sulfonamide handle could be added via metallation and quenched with propyl disulfide. Sulfide 2Q can also be prepared via a nucleophilic displacement of the chlorobenzamide 21. A second metallation of 2Q gave the ethanol derivative 22. Base hydrolysis to the amide to the carboxylate, then lactonization under acidic conditions, gave the isocoumarin 22. Oxidative chlorination and amination proceeded without a problem. 

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