Carboximidoyl chlorides

Carboximidoyl chlorides may be reacted with oximes to give 30-65% yield of amidines, which may then be used to form imidazoles in good yields, by treatment with TsOH (equation 201)716. Highly substituted imidazoles may be prepared in a simple one-pot synthesis by treating vicinal tricarbonyl compounds with an aldehyde and ammonium acetate (equation 202)717. The reaction occurs in 66-90% yield and seems to be general in scope. 

Sequential [3+2] cycloaddition/silicon-based cross-coupling reactions allowed for the synthesis of 3,4,5-trisubsti-tuted isoxazoles. Regioselective 1,3-dipolar cycloaddition reactions between alkynyldimethylsilyl ethers 400 and ethyl or phenyl nitrile oxides, generated in situ from 1-nitropropane and A -hydroxybenzene carboximidoyl chloride, respectively, gave as predominant products after hydrolysis isoxazol-4-ylsilanols 401, converted into 4-arylisoxazoles 402 by cross-coupling with a variety of aryl iodides (Scheme 97) <2005JOC2839>. 

The four-atom unit is an unsaturated 6-amino ester, 6-amino nitrile, 6-amino amide, or an equivalent structure (Scheme 85). The two-atom unit is an isocyanate or an isothiocyanate, a carboximidic ester or carboximidoyl chloride, a thioamide, an amide or amidine, a cyanamide, a carbodiimide, and a nitrile . 

---