Approaches to the synthesis of azabullvalene

<p>"Three approaches to the synthesis of the heretofore unknown azabullvalene, the pi electron equivalent heterocyclic congener of bullvalene itself, are described. Two of the schemes are based upon the assumption that the most convenient method for the introduction of the nitrogen atom is via thermal rearrangement of the appropriate azide.</p> <p>The first involved the generation of the homobarrelene carbon skeleton and sub sequent decomposition of its azide. This compound arises formally as the product of the Diels-Alder addition of acetylene to the bicyclic valence isomer of tropyl azide (cyclohepta-1, 3, 5- trienyl-7-azide). In order to achieve this goal, Diels-Alder additions to 7- substituted tropilidene s were examined. A total of sixty-four possible combinations were analyzed. Additionally, an investigation into the diazo transfer reaction occurring upon cycloalkyl amines for the purpose of generation of cycloalkyl azides was undertaken. Cyclepropyl amine did not furnish cyclopropyl azide by this method. However, the technique was successfully applied to cyclobutyl through cyclooctyl amines and described by us last year. Subsequently, by employing N -nitro so-N-bicyclo [4.1.0] heptyl ethyl carbamate, we have worked out the conditions for the generation of simple cyclopropyl azides and defined suitable reaction conditions for their controlled decomposition to furnish 1-azetine derivatives. Thermolysis of exo- 7- azidobicyclo [4.1.0] heptane furnished 2- azabicyclo [4.2.0] oct-2-ene, which was characterized by analysis of the benzoyl derivative of its reduction product and by hydrolysis to the corresponding aminoaldehyde.</p> <p>A second scheme involved thermal rearrangement of the compound obtained from the formal addition of acetylene to the recently reported azocine (aza-cyclooctatetraene), the pi electron equivalent nitrogen heterocyclic derivative of cyclooctatetraene. Although azocine was not isolated due to its apparent instability and rapid rearrangement, we have demonstrated a workable method for its generation. A third approach to azabullvalene proceeded from the decomposition of the appropriate tropyl carboxazide by an analogous series of the reactions reported in the carbocyclic series.</p> <p>An estimation of the thermodynamic properties of azocine as well as the nitrogen derivatives of bullvalene precursors indicated a large thermodynamic preference for decomposition via hydrogen cyanide ejection. Thus, it appeared that facile loss of HCN will have a major influence upon the isolation of nitrogen analogues of C₈H₈ and C₁₀H₁₀ hydrocarbons"--Abstract, pages ii-iii. </p>

Name thesis:degree_name

Ph. D. in Chemistry

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Steinheimer, Thomas Rudolph

• Chemistry

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/237

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1239