Acylanthranils. 11. Reaction of Acylanthranils with Alcohols To Give the Corresponding Esters

Article abstract of DOI:10.1021/jo00141a004

Although the reactions of acetylanthranil (1, R = CH3) with nucleophilic molecules of the type HNu usually occur "abnormally" via nucleophilic attack at the less electropositive center, C-2 (pathway A, Scheme II), it was shown that reactions of 1 with the anion form, Nu(1-), always occur "normally" via nucleophilic attack at the more electropositive center, C-4 (pathway B, Scheme II).Thus, reaction of 1 with ROH in the presence of a small amount of RO(1-) gives the corresponding o-acetamidobenzoate ester 4 in very good yields, rather than the corresponding acetimidate 3.These results are consistent with the hypothesis that the "abnormal" selectivity is attributable to formation of a molecular complex, 1*(HNu)n, via hydrogen bonding with the heterocyclic nitrogen atom of 1, which favors subsequent nucleophilic attack at the adjacent electropositive center at C-2.Since Nu(1-) cannot be restrained by the tether of hydrogen bonding to the electron donating atoms of 1, reaction occurs "normally" via direct nucleophilic attack at C-4.