Synthesis and Spectroscopic Characterization of the First Mixed Six- and Seven-Membered Heterocyclic Boron Compounds With Intramolecular N→B Bond

The precursor three-coordinate boron compounds of the type (G)BOPri (where G = 2,2'-biphenolate and 2,5-dimethyl-2,5-hexanediolate) have been prepared by the reactions of boron isopropoxide with 2,2'-dihydroxybiphenyl and 2,5-dimethyl-2,5-hexanediol. The reactions of these precursor derivatives with N-arylsalicylaldimines, HOC6H4CH=NAr (where Ar = C6H5, C6H3Me2-2,6; C6H2Me3-2,4,6; C6H3Et2-2,6; C6H3Pr2i-2,6) afforded the synthesis of six- and seven-membered mixed cyclic glycolate-salicylaldiminate derivatives of boron containing intramolecular N -> B bond. All these derivatives have been characterized by elemental analysis, spectroscopic (IR, H-1 and B-11 NMR) studies, as well as by molecular weight determinations. C-13 NMR spectra of three typical derivatives have also been studied.