83469-43-6

Basic information

• Product Name: 4H-cyclobutaphenanthrene
• Synonyms: 4H-cyclobutaphenanthrene
• CAS NO: 83469-43-6
• Molecular Weight: 190.244
• Mol File: 83469-43-6.mol
• Article Data: 3

Chemical Properties

• CAS DataBase Reference: 4H-cyclobutaphenanthrene(CAS DataBase Reference)
• NIST Chemistry Reference: 4H-cyclobutaphenanthrene(83469-43-6)
• EPA Substance Registry System: 4H-cyclobutaphenanthrene(83469-43-6)

Safety Data

• Hazardous Substances Data: 83469-43-6(Hazardous Substances Data)

Upstream product

• 53137-61-4 sodium salt of the tosylhydrazone of phenanthrene-9-carboxaldehyde 
• 98370-88-8 5-(phenanthren-9-yl)-2H-tetrazole 
• 83469-42-5 trimethylsilane 

Relevant articles and documents

Synthesis of peri-cyclobutarenes by thermolysis of [methoxy(trimethylsilyl)methyl]arenes

[Methoxy(trimethylsilyl)methyl]arenes are readily prepared by reactions of chlorotrimethylsilane with (α-methoxy)arenylmethyllithium reagents as obtained from (methoxymethyl)arenes and t-BuLi. The [methoxy(trimethylsilyl)methyl]arenes eliminate methoxytrimethylsilane at 525-675 °C/0.05-0.10 mm to yield peri-cyclobutarenes as derived from arenylcarbenes. Of importance is the fact that the initial arenylcarbenes generated insert into adjacent peri C-H bonds and/or isomerize to other arenylcarbenes that insert into their peri C-H bonds to give peri- cyclobutarenes. Thus, flash-vacuum pyrolysis of 1- [methoxy(trimethylsilyl)methyl]naphthalene (13) at 575-675 °C/0.05-0.10 mm yields 1H-cyclobuta[de]naphthalene (6, up to 39%) in practical quantities. 2- [Methoxy(trimethylsilyl)methyl]naphthalene (23) also affords 6 as a major thermolysis product. At 510 °C/0.05-0.10 mm 4-methoxy-1- [methoxy(trimethylsilyl)methyl]naphthalene (29) decomposes to 4-methoxy-1H- cyclobuta[de]naphthalene (31, 46%). Under similar conditions, 2-methoxy-1- [methoxy(trimethylsilyl)methyl]naphthalene (33) converts to 1,2- dihydronaphtho[2,1-b]furan (35, 64%) and naphtho[2,1-b]furan (36, 31%), presumably by insertion of 2-methoxy-1-naphthylcarbene (34) into a C-H bond of its o-methoxy group and then dehydrogenation of the resultant dihydrofuran. Further, 1-[methoxy(trimethylsilyl)methyl]-6-methylnaphthalene (39) pyrolyzes (510 °C/0.10-0.20 mm) to 6-methyl-1-naphthylcarbene (40), which isomerizes in part to 7-methyl-1-naphthylcarbene (49); carbenes 40 and 49 then undergo peri C-H insertion to give 3-methyl-1H- cyclobuta[de]naphthalene (41) and 2-methyl-1H-cyclobuta[de]naphthalene (42) in an 8:1 ratio and a combined yield of 44%. The pyrolytic method is particularly valuable for preparing higher peri single carbon atom bridged arenes such as 4H-cyclobuta[jk]phenanthrene (53, 65%) and 3H- cyclobuta[cd]pyrene (59, 86%).

PERI-METHANOARENES BY THERMOLYSIS OF TRIMETHYLSILANES

Practical syntheses of varied peri-methanoarenes have been developed.