Amides halides

The use of oximes as nucleophiles can be quite perplexing in view of the fact that nitrogen or oxygen may react. Alkylation of hydroxylamines can therefore be a very complex process which is largely dependent on the steric factors associated with the educts. Reproducible and predictable results are obtained in intramolecular reactions between oximes and electrophilic carbon atoms. Amides, halides, nitriles, and ketones have been used as electrophiles, and various heterocycles such as quinazoline N-oxide, benzodiayepines, and isoxazoles have been obtained in excellent yields under appropriate reaction conditions. 

I. Action of Acids, Acid Amides, Halides and Anhydrides... 

Guanamines are obtainable from biguanides by the action of reagents other than esters. These include the amides, halides and anhydrides of organic acids, as well as the acids themselves. 

The pyrazolo-fused pyrimido[4,5-< ]-l,2,4-triazine 35 was synthesized using the 5-amino-6-cyano triazine 131 (Scheme 21) as the precursor. Reaction with phosgeniminium chloride gave the amide halide intermediate 132 which in turn produced the pyrimido[4,5-< ]-l,2,4-triazine 35 upon treatment with gaseous hydrogen chloride <1996T3037>. 

This synthetic method is of great importance in the synthesis of silicon amides. Halides of the type R SiCL,. (x = 0, 1, 2, 3) react with ammonia or primary and secondary amines to give the corresponding amides.17"24 Again, with sterically demanding amines only partial halide displacement is possible (equations 6 and 7).22,23... 

Acid derivatives including esters, amides, halides and nitriles are readily accessible. Dicyanofuroxan (72) shows in its reactions some similarities to phthalonitrile (75LA1029) it also provides a source of fused pyridazino- and oxazino-furoxans (73) and (74) via addition with hydrazine and hydroxylamine, respectively (82H(19)1063). The tetronic acid compound (75) yields a hydroxyamide (76) on aminolysis (79S977). 

From 1,1,1-trihaloalkanes, amide halides and related compounds 579... 

Synthesis ofiminium Salts, Orthoesters and Related Compounds 2.7.2.2 Halomethyleneiminium Salts (Amide Halides)... 

Phosgene, as well as the easier to handle diphosgene (chloroformic acid trichloromethyl ester) or triphosgene (carbonic acid bis(trichloromethyl) ester) transform primary, secondary and tertiary amides and thioamides to chloromethyleneiminium chlorides (25 equation 15), whereby the reaction with thioamides is of broader scope and proceeds with fewer side reactions. The amide chlorides derived from primary and secondary amides can lose HCl, giving nitriles or imidoyl halides, respectively. /V-Sub-stituted formamides can be converted to isonitriles via amide halides. ... 

Dihalomethyleneiminium salts undeigo condensation reactions with CH-acidic compounds such as ketones, carboxylic acid chlorides, nitriles and amides, to give amide halides, e.g. (51 equation... 

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