Synthesis and Molecular Structure of 2,4,8a‐Triaryl‐6‐methylperhydro[1,3,2]dioxaborinino[5,4‐c]pyridines.

Abstract

Organo-boron compounds S 0040Synthesis and Molecular Structure of 2,4,8a-Triaryl-6-methylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines. -Condensation of 1,3-diol (I) with arylboronic acids affords the title compounds (III), which are representatives of a new heterocyclic system. Their stereochemistry and molecular structures are established by single crystal X-ray diffraction analysis. -(LE TUAN ANH; POLYANSKII, K. B.; ANDRESYUK, A. N.; SOLDATENKOV*, A. T.; MAMYRBEKOVA, Z. A.; KULESHOVA, L. N.; KHRUSTALEV, V. N.; Russ. Chem. Bull. 53 (2004) 4, 842-845; Russ. Peoples' Friendship Univ., Moscow 117198, Russia; Eng.) -D. Singer 03-165

Synthesis and spectral characteristics of 2-aryl-6-methyl-and 2-aryl-6-benzyl-4,8a-diphenylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines

“…The triplet shape of this signal and large coupling constant (10.08-11.3 Hz) suggest, by analogy with similar characteristics for the cyclohexane system, that this proton has axial orientation relative to both cis-fused rings (this has been confirmed by X-ray diffraction structural data for 2a [2]) as well as trans position relative to H-4 and H e -5 protons. The axial orientation of H-4 proton is indicated by the broad half-height width of its unresolved signal.…”

“…The reaction course and purity of the isolated products were monitored by thin-layer chromatography on Silufol UV-254 plates with ethyl acetate as the eluent and development by iodine vapor. Piperidols 1a and 1b were obtained in three steps: 1) condensation of acetophenone with formaldehyde and methylamine or benzylamine, leading to the corresponding Mannich salts [3]; 2) cyclization of these salts to give 3-benzyl-4-phenylpiperidols [3]; 3) reduction of these piperidols to 1,3-diols [2,3].…”

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We have previously reported the synthesis of perhydro[1,3,2]dioxaborinino [5,4-c]pyridines, which are representatives of a new class of compounds containing four heteroatoms, from N-methyldiol 1a and a series of arylboronic acids 2a-f [1,2]. In the present work, we describe the synthesis of new N-methyl-and N-benzyl-2-aryl-4,8a-diphenylperhydrodioxaborninopyridines 2g-j and 3a-d from diol 1a and N-benzyldiol 1b, respectively, and arylboronic acids (Scheme 1) and examine the 1 H NMR and mass spectra of 2a-j and 3a-d. Products 2g-j and 3a-d were synthesized, similarly to 2a-f, by the tandem diesterification of piperidols 1a and 1b with arylboronic acids upon heating these compounds in toluene at reflux.

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