3-Azabicyclo[3.3.1]nonane Derivatives: IV. Synthesis of Amino Acids with 3-Azabicyclo[3.3.1]nonane Fragment

A series of 1.5-dinitro-3-azabicyclo[3.3.1]non-6-enes was prepared by reduction of 1-R-2,4- and 1-R-3,5-dinitrobenzenes with potassium borohydride followed by Mannich reaction with formaldehyde and amino acids. The molecular structure of (6-bromo-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid was studied by X-ray diffraction analysis. The mechanism of decomposition under electron impact was determined for (7-methoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid.     

3-Azabicyclo[3.3.1]nonane Derivatives: V. Synthesis of 7-Polyfluoroalkoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

A number of 7-polyfluoroalkoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes were synthesized by reduction of 3,5-dinitrophenyl polyfluoroalkyl ethers with sodium tetrahydridoborate, followed by the Mannich reaction with formaldehyde and primary amines.     

Synthesis and Stereochemistry of Some 3-Azabicyclo[3.3.1]nonane Derivatives

Michael reactions of methyl (ethyl) 1-benzyl-4-oxopiperidine-3-carboxylates with a number of ,-unsaturated carbonyl compounds result in formation of 6- and 6,8-substituted methyl (ethyl) 3-benzyl-9-oxo-3-azabicyclo[3.3.1]nonane-1-carboxylates. Stereochemical aspects of these reactions were studied, and some further transformations of the products were performed.     

3-Azabicyclo[3.3.1]nonane Derivatives: VIII. Synthesis and Properties of 6(7)-R-3,3-Dimethyl-1,5- dinitro-3-azoniabicyclo[3.3.1]non-6-ene Iodides

N-Alkylation of 6(7)-R-1,5-dinitro-3-methyl-3-azabicyclo[3.3.1]non-6-enes with methyl iodide afforded a series of quaternary ammonium salts whose yield depended on the solvent polarity and character of substituents located in positions 6 or 7 of substrate. The presence of electron-withdrawing groups reduced the yield of the target products compared to unsubstituted compound, whereas the electron-donor substituents increased the yield. As shown by the X-ray diffractionstudy the congormation of the substances was not changed in the course of quaternization. The DTA-TG analysis revealed that in the first stage of thermolysis the 6(7)-R-3,3-dimethyl-1,5-dinitro-3-azoniabicyclo[3.3.1]non-6-ene iodides suffer dealkylation. Two fragmentation paths of compounds synthesized under electron impact were observed: elimination either of methyl iodide or aziridinium cation.     

Chemistry of 3-Azabicyclo[3.3.1]nonane: II. Reduction of 6-Acetoxy-3-benzyl-1- ethoxycarbonyl-3-azabicyclo[3.3.1]nonan-9-one with Sodium Borohydride

Reduction of 6-acetoxy-3-benzyl-l-ethoxycarbonyl-3-azabicyclo[3.3.1]nonan-9-one with sodium borohydride was investigated in various conditions. The stereochemistry of reduction products was deduced from ¹H and ¹³C NMR and mass spectra.     

Synthesis of novel piperazine based building blocks: 3,7,9-triazabicyclo[3.3.1]nonane, 3,6,8-triazabicyclo[3.2.2]nonane, 3-oxa-7,9-diazabicyclo[3.3.1]nonane and 3-oxa-6,8-diazabicyclo[3.2.2]nonane

The preparation of four novel bridged piperazine building blocks is described: 3,7,9-triazabicyclo[3.3.1]nonane 1, 3-oxa-7,9-diazabicyclo[3.3.1]nonane 2, 3,6,8-triazabicyclo[3.2.2]nonane 3 and 3-oxa-6,8-diazabicyclo[3.2.2]nonane 4. The scaffold of 1 was synthesized from N,N′-dibromobenzenesulfonamide and ethyl acrylate. Compound 2 may be prepared from identical starting materials or alternatively from α,α′-diglycerol. Compounds 3 and 4 were identified as side products from possible aziridinium intermediates.     

Synthesis and Chemical Transformations of 7-Hydroxybicyclo[3.3.1]nonane-3-carbohydrazide

Russian Journal of Organic Chemistry - The reaction of 4-oxahomoadamantan-5-one with hydrazine gave (3-exo,7-endo)-7-hydroxybicyclo[3.3.1]nonane-3-carbohydrazide. The latter was reacted with...     

Pseudo-Five-Component Stereoselective Synthesis of Highly Functionalized 3-Azabicyclo[3.3.1]nona-2,7-dienes

Russian Journal of General Chemistry - The reaction of aromatic aldehydes with malononitrile, ethyl or butyl cyanoacetate and acetylacetone in the presence of NaOH under mild conditions (EtOH,...     

Synthesis,crystal and molecular structure of 3,7-ditosyl-1,5-diphenyl-3,7-diazabicyclo[3.3.1]nonane

3,7-Ditosyl-1,5-diphenyl-3,7-diazabicyclo[3.3.1]nonane has been found to adopt a chair–chair conformation in the crystalline state in contrast to 3,7-ditosyl-1,5-diphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one, which had been previously found to exist in a chair-boat conformation.     

The chemistry of piperidines—I : 3-Azabicyclo[3.3.1]nonanes

The reaction of pyrrolidine, piperidine and morpholine enamines of 1-methyl-4-piperidone with acraldehyde is found to be a convenient route to 3-aza-3-methyl-6-cycloalkylaminobicyclo[3.3.1]-nonan-9-ones. In each case two difficultly separable ketones are obtained which on reduction give mixtures of isomeric alcohols. The alcohols are separated and their stereochemistries are determined from their physical and chemical properties.     

Conformational behavior of 3-borabicyclo[3.3.1]nonanes: 1. Study of molecular dynamics in 3-methoxy-7α-phenyl-1,5-dimethyl-3-borabicyclo[3.3.1]nonane

3-Methoxy-7α-phenyl-1,5-dimethyl-3-borabicyclo[3.3.1]nonane 5 in solution at room temperature exists in the double chair conformation, as shown by NMR studies. Increasing the temperature leads to an increase in the population of the chair–boat conformation. At decreased temperature hindered rotation around the B---O bond is observed for 5. Dissolving 5 in deuteropyridine leads to the reversible formation of complex 6, which exists in the chair–boat conformation. The chair–boat conformation is also the most stable one for chelate compound 7 with a tetracoordinated boron atom.     

Conformational analysis of 3-borabicyclo[3.3.1]nonane derivatives

Conformations of 3-borabicyclo[3.3.1]nonane derivatives have been studied by means of ¹H and ¹³C NMR spectroscopy. With the aid of the coupling constants ³J(HH) and ¹³C chemical shifts it has been shown that all the derivatives of 3-borabicyclo[3.3.1]nonane with the trigonal boron atom studied are in a flattened double-chair conformation. In 3-borabicyclo[3.3.1]nonane derivatives with the tetra-coordinated boron atom and substituents at the 7α-position, the chair-boat conformation predominates, the boat conformation being characteristic of the cyclohexane ring; exceptions are the compounds with the internal donor—acceptor bond between the boron atom an 7α-substituent.