63548-78-7

Basic information

• Product Name: 1,4,5,8-tetramethylbiphenylene
• CAS NO: 63548-78-7
• Molecular Formula: C₁₆H₁₆
• Molecular Weight: 208.2982
• Mol File: 63548-78-7.mol
• Article Data: 4

Chemical Properties

• Boiling Point: 338.1°C at 760 mmHg
• Flash Point: 149.9°C
• Density: 1.079g/cm³
• Vapor Pressure: 0.000196mmHg at 25°C
• Refractive Index: 1.692
• CAS DataBase Reference: 1,4,5,8-tetramethylbiphenylene(CAS DataBase Reference)
• NIST Chemistry Reference: 1,4,5,8-tetramethylbiphenylene(63548-78-7)
• EPA Substance Registry System: 1,4,5,8-tetramethylbiphenylene(63548-78-7)

Safety Data

• Hazardous Substances Data: 63548-78-7(Hazardous Substances Data)

Usage

Structure

Consists of a benzene ring with four methyl groups attached at the 1, 4, 5, and 8 positions

Type

Biphenyl derivative

Applications

Used as a building block in the synthesis of various organic compounds, including pharmaceuticals, dyes, and polymers

Physical properties

Unique and symmetrical structure due to the presence of four methyl groups on the biphenylene ring

Chemical properties

Distinct properties due to the presence of the four methyl groups, making it suitable for specific industrial and research applications

Versatility

Interesting and versatile compound for further study and potential use in various fields

Upstream product

• 131543-46-9 Glyoxal 
• 41634-34-8 cyclobutanaphthalene-1,2-dione 
• 87739-06-8 1,4,5,8-tetrakis<(triphenylphosphonio)methyl>biphenylene tetrabromide 
• 15540-84-8 2,3-dibromo-1,4-dimethylbenzene 
• 68596-88-3 3,6-dimethylbenzenediazonium 2-carboxylate 
• 6383-11-5 benzocyclobutene-1,2-dione 
• 15540-90-6 4,7-dimethyl-indole-2,3-dione 
• 15540-89-3 N-(2,5-dimethylphenyl)-2-hydroxyiminoacetamide 
• 95-78-3 2,5-Dimethylaniline 
• 15540-91-7 2-amino-3,6-dimethylbenzoic acid 
• 5463-50-3 3,6-dimethyl phthalic anhydride 

Relevant articles and documents

MP2 and DFT calculations on circulenes and an attempt to prepare the second lowest benzolog, [4]circulene

MP2 and DFT calculations have been carried out for [n]circulenes for n=3 to 20 in order to predict the strain energy and topology of these cyclically condensed aromatic systems. To synthesise [4]circulene (2), 1,5,7,8- tetrakis(bromomethyl)biphenylene (14) was prepared from the corresponding tetramethyl derivative (8) and subjected to various dehalogenation reactions; all attempts to obtain [2.2]biphenylenophane (7) as a precursor for 2 by this route failed. Treatment of 14 with sodium sulfide furnished the thiaphanes 16 and 17, thermal and photochemical desulfurization of which also failed to provide 7. In a second approach [2.2]paracyclophane was converted to the pseudo-geminal dithiol23, which was subsequently bridged to the thiaphanes 22 and 24. On flash vacuum pyrolysis at 800°C these were converted exclusively into phenanthrene (30). An approach to dehydrochlorinate the commercial product PARYLENE C to the tetrahydro[4]-circulene 7 led only to polymerisation. The X-ray structures of the intermediates 8, 14, 17, 23, 24, 26, and 35 are reported.

Cyclooctannelated Biphenylenes. Diagnosis of an Anomalous Bond Length by Analysis of Ring Current Geometric Factors

The syntheses and properties of the benzocyclobutene- and naphthocyclobutene-fused dicyclooctabiphenylenes 8 and 9 are described.These ? systems show paratropic 1H NMR effects with magnitudes between those of the parent hydrocarbon dicyclooctabiphenylene (7) and the cyclooctabiphenylenes 1,2,and 3.A complete 1H NMR spectral analysis was performed on a series of 14 polycyclic hydrocarbons related to biphenylene (10) including 1-3 and 7-9.A self-consistent Heuckel-McWeeny ring current model provided an excellent description of the 1H NMR spectra observed for these polycycles.Correlation of biphenylenic 1H NMR chemical shifts with calculated ring currents for the polycycles 1,2,3,7,8,9, and 10 afforded a semiempirical determination of ring current geometric factors for these systems.Deviations of certain observed geometric factors from theoretical "Biot-Savart" values were found to be diagnostic for an unusually long bond in the cyclobutene ring of the higher annelates 2,3,8, and 9.