Anthranils, reaction with hydrazine

Anthranilic acid reacts with the fused-ring chloroimine 155 in ethanol at 170°C to give the pentacycle 156 (Equation 38), and similar compounds can be prepared from the keto-ester 157 by reaction with hydrazine in acetic acid (Equation 39) <2003HC0181>. 

With respect to time and cost, this method is superior to the five-step synthesis from anthranilic acid. Older literature sources have been cited in an earlier volume of Organic Syntheses. Indazole has also been prepared recently by the reaction of 2-hy-droxymethylenecydohexanone with hydrazine and dehydrogenation of the 5,6,7,8-tetrahydro derivative. ... 

Similarly, 3-amino-4(3//)-quinazolinones (600) are formed in high yields when methyl or ethyl o-acylaminobenzoates are heated with hydrazine in an alcohol. Alternatively, acylation and cyclization of an o-aminobenzoylhydrazine is effected by heating with anhydrous formic acid, ethyl orthoformate, or acetic anhydride. Related is the action of heat on a mixture of anthranilic esters and semicarbazides to yield A3-aminated 2,4(1//,3//)-quinazolinediones (601). Reactions which involve... 

Dihydro - 2,2,4 - trimethyl - 2H,6H -1,3,4-oxadiazino[2,3-6]quinazolines (654) were synthesized together with 2,3-dihydro-3-methyl-2-thioxo-6H-1,3,4-thiadiazolo[2,3-6]quinazolines by the reaction of isatoic anhydrides with l-[(2-hydroxy-2-methyl)propyl]hydrazine to give the corresponding anthranilic acid hydrazides (652), which were cyclized to the quinazoline intermediates 653 and then to 654 (79JHC1339). 

The synthesis starts from anthranilic acid which is first diazotized and the selenium introduced by treatment of the diazonium salt with Li2Sc2, obtained from elemental lithium and selenium in an aptotic medium <1993LA1239> or better with Na2Se2, prepared in advance by the reaction of selenium powder, 100% hydrazine hydrate, and sodium... 

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