7090-45-1Relevant academic research and scientific papers
BIPHENYLENES AND HETEROCYCLIC ANALOGUES OF BIPHENYLENE. PART 6. CHLORINATION OF 4,5,9,10-TETRA-AZAPHENANTHRENE AND PREPARATION OF HEXACHLORO-1,8-DIAZABIPHENYLENE
Kilcoyne, John P.,MacBride, J. A. Hugh,Muir, Max,Wright, Peter M.
, p. 215 - 237 (2007/10/02)
Chlorination of 4,5,9,10-tetra-azaphenanthrene with phosphorous pentachloride in a stainless steel autoclave at 240 deg C gave hexachloro-4,5,9,10-tetra-azaphenanthrene in small scale experiments but scale-up required addition of free chlorine.At lower temperatures tetrachloro- and pentachloro-derivatives were formed in which proton nmr showed that positions adjacent to pyridine nitrogen remained unchlorinated and it is proposed that these positions react by radical substitution whereas those meta and para to ring nitrogen undergo electrophilic chlorination which is suppressed by phosphorus trichloride.Vacuum pyrolysis of hexachloro-4,5,9,10-tetra-azaphenanthrene gave hexachloro-1,8-diazabiphenylene in low yield, in contrast with the corresponding preparation of octachlorobiphenylene whose formation under milder conditions is attributed to steric strain in the precursor.
BIPHENYLENES AND HETEROCYCLIC ANALOGUES OF BIPHENYLENE. PART I. PREPARATION OF BIPHENYLENE AND OCTACHLOROBIPHENYLENE BY VACUUM PYROLYSIS OF BENZO(c)CINNOLINES; PYROLYSIS OF BENZOCINNOLINE N-OXIDE.
Kanoktanaporn, Santhi,MacBride, J. A. Hugh
, p. 2901 - 2910 (2007/10/02)
Vacuum sublimation of benzocinnolines through a silica tube at 700-950 deg C gives biphenylenes in good yield.The first reaction when benzocinnoline N-oxide is similarly pyrolysed is deoxygenation to benzocinnoline.
