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The synthesis of 2,4,8a-triarylperhydro[1,3,2]dioxaborinino [5,4-c]pyridines with aryl substituents at the boron atom has been reported [1-3]. The preparation of indicated derivatives of new heterocyclic systems was dictated by the observation that many of them when subjected to the PASS program [4] should possess (to a high degree of probability) effects on the central nervous system. In the same connection the molecular structure of B-phenyl-substituted perhydrodioxaborininopyridine was studied in detail -a racemic diastereomer for which cis-fusion of the two heterocyclic units was established, with three chiral atoms, C(4), C(4a), and C(8a) with the R-, S-, and S-configurations respectively [2]. In the present paper the syntheses of B-(2-propoxy)-(2a) and B-hydroxyperhydro[1,3,2]dioxaborinino [5,4-c]pyridine (2b) are described, based on the substituted γ-piperidol 1, and also their structural analog 2c in which the boron atom is replaced by the CH 2 group; the __________________________________________________________________________________________

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. These products were separated by column chromatography. Their composition and structure were supported by elemental analysis and 1 H NMR spectroscopy (Tables 1 and 2) as well as the nature of their decomposition upon electron impact (Table 3).The signal for H-4a provides the most useful information in the 1 H NMR spectra of 2g-i, 3a-b. 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. __________________________________________________________________________________________

Organo-boron compounds S 0040 Synthesis and Molecular Structure of Substituted 2-Hydroxyperhydro[1,3,2]dioxaborinino[5,4-c]pyridines, Perhydro[1,3]dioxano[5,4-c]pyridine, and Their Precursor -4-Hydroxy-3-(α-hydroxybenzyl)-1-methyl-4-phenylpiperidine. -Title perhydropyridines [(III), (V) and (VI)] are synthesized starting from piperidine (I) and their molecular and crystal structures are determined by X-ray crystallography. Interestingly, formation of dioxanopiperidine (III) is accompanied by an inversion at the C-8 phenyl position. -(ANH, L. T.; SOLDATENKOV*, A. T.; MAMYRBEKOVA, Z. A.; SOLDATOVA, S. A.; POLYANSKIY, K. B.; TUNG, T. T.; KHRUSTALEV, V. N.; Chem. Heterocycl.

Organo-boron compounds S 0040Synthesis and Spectral Characteristics of 2-Aryl-6-methyl-and 2-Aryl-6-benzyl-4,8a-diphenylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines. -Newly synthesized title heterocycles (IIIa)-(IIIc) do not show activity against E. coli 1157 (a hospital strain of wound infection) and Staphylococcus albus. -(ANH, L. T.; POLYANSKIY, K. B.; MAMYRBEKOVA, J. A.; SOLDATENKOV, A. T.; SOLDATOVA*, S. A.; KURILKIN, V. V.; TERENTIEV, P. B.; Chem. Heterocycl.