Approaches to the synthesis of diazabiphenylenes

Cyclopent-2-enone was prepared from either dicyclopentadiene or cycopentanone, and then converted to the photodimer cis,trans,cis-tricyclo[5,3,0,0 2,6]decane-3,8- dione. A limited investigation was conducted into the Beckmann rearrangement of the dioxime(s) of this diketone and polyphosphoric acid then used as a catalyst to give the expected cis,trans,cis-4,10-diazatricyclo[6,4,0,0 2,7]- dodecane-3,9-dione as the major product. The Schmidt reaction of the diketone gave the known cis,trans,cis- 3,9-diazatricyclo[6,4,0,0 2,7]dodecane-4,10-dione, which was converted into its N,N'-dibenzyl derivative. The two dilactams were reduced to the corresponding amines cis,trans,cis-4,10-diazatricyclo[6,4,0,0 2,7]-dodecane and cis,trans,cis-3,9-diazatricyclo[6,4,0,0 2,7]-dodecane, with diborane, the structures of which were established on the basis of their spectroscopic properties and also those of their N,N'-bis(4-nitrobenzoyl) derivatives. The N,N'-dibenzyl derivative of the latter dilactam was reduced with lithium aluminium hydride to the known tertiary amine. The catalytic dehydrogenation of the tertiary amine with palladium on carbon gave two products, one of which was shown to be 2,3'-bipyridine, and the other tentatively identified as either 3- or 4-benzylpyridine. A repetition of this reaction, using nitrobenzene as a solvent, again gave two products, one of which was established as benzylideneaniline and the other also tentatively identified as either 3- or 4-benzylpyridine. Following initial dehydrogenation studies on piperidine as a model compound, the catalytic dehydrogenations of the above two amines was attempted, both neat and in solution. However, it appeared that polymeric material only was produced and no identifiable products were observed for any of the reactions. Attempts to prepare the 0,0'-dimethyl derivatives of the dilactams from the Beckmann and Schmidt reactions were unsuccessful, but following experiments with a model compound, piperazine-2,5-dione, treatment of the dilactams with triethyloxonium tetrafluoroborate gave the lactim ethers cis,trans,cis-3,9-diethoxy-4,10-diazatricyclo-[6,4,0,0 2,7] dodeca-3,9-diene and cis,trans,cis-4,10-diethoxy-3,9-diazatricyclo[6,4,0,0 2,7]dodeca-3,9-diene. A minor product cis,trans,cis-9-ethoxy-4,10-diazatricyclo-[6,4,0,0 2,7]dodec-9-en-3-one was also isolated from the former reaction and the structures of all three compounds were established on the basis of their spectroscopic properties. The attempted dehydrogenations of these two lactim ethers with 2 , 3-dichloro-5,6-dicyano-l,4-benzoquinone did not give any diazabiphenylenes.

Level dc:type.qualificationlevel

mphil

Grantor dc:publisher.institution

Thames Polytechnic

Year dc:date.issued

1983

Author dc:creator

• Packham, Terence William

Advisors dc:contributor.advisor

• Rogers, V.
• Smith, P.

• QD Chemistry

Language dc:language

en