Oximoyl chlorides

Dipolar cycloaddition of nitrile oxide at the C=N bond of indole imino esters 130, followed by elimination of the alcohol moity gives oxadiazole derivatives 131 (Scheme 1.26) (298). Reaction of N-arylbenzamidines with arenenitrile N-oxides (generated in situ from oximoyl chlorides) produce unstable 5-amino-4,5-dihydro-1,2,4-oxadiazoles which, on aqueous acidic treatment hydrolyze to open-chain N-benzoyloxy-N -arylareneamidines (299). 

Oximoyl chlorides. Through simultaneous dichlorination and reduction, ni-troalkenes are converted to a-chloro-oximoyl chlorides as precursors of nitrile ox-ides. The presence of the a-chlorine may be useful in some synthetic situations. Oximoyl chlorides are obtained when the reaction is conducted in the presence of triethylsilane. ... 

Isoxazole-fused tetrahydroxanthenes can be obtained from the reaction of substituted salicylaldehydes with 2-bromo-2-cyclohexen-l-ol in a multistep approach involving oxime formation, conversion into an oximoyl chloride, intramolecular [3 + 2] cycloaddition and elimination of HBr promoted by silver(I) carbonate (14JOC7250). 

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See also in sourсe #XX -- [ ]

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