Spray Pyrolysis as a Synthetic Tool.
Abstract
The project is concerned mainly with the solution thermolysis and spray vacuum pyrolysis (SVP) of acyl and aryl azides. Under the latter conditions alkyl azidoformates (Ar(CH2)nOCON3; n = 1 or 2) yield 5:7 or 6:7 fused 1H-azepines. The majority of the 5:7 fused systems are unstable and undergo rapid (6 + 4) dimerisation. In contrast, the 6:7 fused systems are stable; the difference in stability is discussed in terms of the hybridisation of the bridgehead nitrogen. Attempts to trap aryl nitrenes intramolecularly by suitably placed OH and NH2 groups have failed. However, some novel polyheterocyclic structures have been obtained from the photo- and thermal decomposition of beta-hydroxyethyl o-azido-benzoate. The thermal decomposition of aryl azides in phenyl isocyanate yields 1-phenyl-3-phenylcarbamoyl-2-oxobenzimidazoles. In some cases N-arylcarbamates (p-XC6H4NHCO2Me) are produced. The mechanism of this surprising reaction is discussed. The behaviour of C-(o-azidobenzoyl) derivatives of alkyl ketones and esters on thermolysis and SVP is unpredictable and leads to a variety of heterocyclic products, dominant amongst which are 2,2-disubstituted indoxyls and 2,1-benz-isoxazoles. Anomolous behaviour is shown by o-azidobenzoyl malononitrile which on thermolysis yields a tetrazoloquinolone. The mechanisms of these reactions are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1984
- Accession Number
- ADA153891
Entities
People
- Damini Patel
- O. Meth-cohn
- R. K. Smalley
Organizations
- University of Salford