78649-21-5

Upstream product

• 23416-98-0 9,10-Dihydro-9,10-propenoanthracene 
• 30122-20-4 cyclopropa-9,10-ethano-9,10-dihydroanthracene 
• 140710-61-8 C₁₉H₁₈O₂ 
• 78649-20-4 2',3'-Dihydro-1,1'-spirobiinden 
• 52703-44-3 2:3,6:7-Dibenzobicyclo[6.1.0]nona-2,4,6-trien 
• 36736-96-6 10,11-dihydro-5,10-ethano-5H-dibenzocyclohepten-12-ol 

Downstream Products

• 238-84-6 benzo[a]fluorene 
• 78649-22-6 3-(2-ethylphenyl)-indene 

Relevant academic research and scientific papers

Flow-vacuum pyrolysis of polycyclic compounds. 101: Pyrolysis of cyclopropa[r]-9,10-ethano-9,10-dihydroanthracene

The title hydrocarbon (11) reacts thermally by two competitive routes: (a) a retrodiene reaction affording anthracene and (b) a sequence of isomerizations generating 9,10-dihydro-9,10-propenoanthracene (1), 1,1a,6,10b-tetrahydro-1,6-methanodibenzo[a,e] cyclopropa[c]cycloheptene (2), 11,11a-dihydro-6aH-benzo[a]fluorene (4), 6,11-dihydro-5H-benzo[a]fluorene (5) and finally through dehydrogenation 11H-benzo[a]fluorene (6).

BENZOANNELATED VALENCE ISOMERS OF HOMOANNULENES. 2. THERMAL BEHAVIOUR OF DIBENZOBICYCLONONA-2,4,6-TRIENE

The flow-vacuum pyrolysis of the title dibenzo(C9H10) hydrocarbon 3 was investigated between 400-650 deg C and 1 Torr.The main reaction product, 11,11a-dihydro-6aH-benzofluorene (5) was isolated and characterized.At elevated temperatures 5 is converted into a mixture of 6,11-dihydro-5H-benzofluorene (6) and 11H-benzofluorene (7).A reaction mechanism for pyrolysis is suggested and a comparison between the thermal behaviour of 3 and of some related hydrocarbons is made.

Benzoannelated valence isomers of homoannulenes. I. Thermal behaviour of some dibenzo(C9H10)hydrocarbons

The flow-vacuum pyrolyses of 9,10-dihydro-9,10-propenoanthracene 1 and 1,1a,6,10b-tetrahydro-1,6-methanodibenzocyclopropacycloheptene 2 (two isomeric dibenzo(C9H10)hydrocarbons occuring in the acetolysis of 5-(β-tosyloxyethyl)-5H-dibenzocycloheptene 4a) were examined at 1.33 mbar and various temperatures between 300 deg C and 700 deg C.The thermal interconversion of 1 and 2 was proved as well as the formation of a new unstable dibenzo(C9H10) valence isomer, 3, which is converted further at higher temperatures into stable benzofluorene derivatives 6 and 7.Radical mechanisms are proposed and the possibility of formation of another transient dibenzo(C9H10)hydrocarbon 30 is supposed.The essential role of the CH2 moiety in pyrolyses of the investigated hydrocarbons is underlined and a comparsion of pyrolysis mechanisms in C9H10-, benzo(C9H10)- and dibenzo(C9H10)-series is made. Key words: valence isomers of homoannulenes / dibenzo(C9H10)hydrocarbons / flow-vacuum pyrolysis

HOMO- AND SPIROCONJUGATIVE EFFECTS IN THE SIGMATROPIC REARRANGEMENT OF 1,1'-SPIROBIINDENES

Due to homoconjugative interactions 2,3-dihydro-1,1'-spirobiindene and 1,1'-spirobiindene yield isomeric benzofluorenes in thermal, photochemical, and electron transfer induced rearrangement.