27041-32-3Relevant academic research and scientific papers
Improved synthesis of benzocyclobutenone by flash vacuum pyrolysis
Suzzarini, Laurence,Lin, Jian,Wang, Zhi Yuan
, p. 1695 - 1696 (1998)
Flash vacuum pyrolysis of o-toluoyl chloride at 780 °C under 0.5 mmHg afforded benzocyclobutenone in higher yield (80%) than previously reported one (28 %).
Nitrile imines: Matrix isolation, IR spectra, structures, and rearrangement to carbodiimides
Begue, Didier,Qiao, Greg Guanghua,Wentrup, Curt
supporting information; scheme or table, p. 5339 - 5350 (2012/05/20)
The structures and reactivities of nitrile imines are subjects of continuing debate. Several nitrile imines were generated photochemically or thermally and investigated by IR spectroscopy in Ar matrices at cryogenic temperatures (Ph-CNN-H 6, Ph-CNN-CH317, Ph-CNN-SiMe323, Ph-CNN-Ph 29, Ph3C-CNN-CPh334, and the boryl-CNN-boryl derivative 39). The effect of substituents on the structures and IR absorptions of nitrile imines was investigated computationally at the B3LYP/6-31G level. IR spectra were analyzed in terms of calculated anharmonic vibrational spectra and were generally in very good agreement with the calculated spectra. Infrared spectra were found to reflect the structures of nitrile imines accurately. Nitrile imines with IR absorptions above 2200 cm -1 have essentially propargylic structures, possessing a CN triple bond (typically PhCNNSiMe323, PhCNNPh 29, and boryl-CNN-boryl 39). Nitrile imines with IR absorptions below ca. 2200 cm-1 are more likely to be allenic (e.g., HCNNH 1, PhCNNH 6, HCNNPh 43, PhCNNCH317, and Ph3C-CNN-CPh334). All nitrile imines isomerize to the corresponding carbodiimides both thermally and photochemically. Monosubstituted carbodiimides isomerize thermally to the corresponding cyanamides (e.g., Ph-N=C=N-H 5 Ph-NH-CN 8), which are therefore the thermal end products for nitrile imines of the types RCNNH and HCNNR. This tautomerization is reversible under flash vacuum thermolysis conditions.
1,2,4,6-CYCLOHEPTATETRAENE: THE KEY INTERMEDIATE IN ARYLCARBENE INTERCONVERSIONS AND RELATED C7H6 REARRANGEMENTS
McMahon, Robert J.,Abelt, Christopher J.,Chapman, Orville L.,Johnson, Jeffery W.,Kreil, Curits L.,et al.
, p. 2456 - 2469 (2007/10/02)
Thermolysis or photolysis of phenyldiazomethane (2) produces phenylmethylene (3), which ring-expands to give 1,2,4,6-cycloheptatetraene (6).Spectroscopic and chemical evidence rule out bicyclo(4.1.0)hepta-2,4,6-triene (4), cycloheptatrienylidene (5), and bicyclo(3.2.0)hepta-1,3,6-triene (11) intermediates.The strained allene in cycloheptatetraene (6) exhibits infrared absorption at 1824 and 1816 cm-1.Deuterium substitution produces the expected 10-cm-1 shift in the allene absorption.Fluorine or chlorine substitution substantially enhances the allene absorption intensity.Deuterium labeling studies reveal that the intramolecular chemistry of cycloheptatetraene (6) involves reversible thermal or photochemical equilibriation with phenylmethylene (3).The intermolecular chemistry of 6 involves dimerization.At temperatures as low as 10 K, 6 forms a labile (2+2) dimer,7, which undergoes thermally allowed, electrocyclic ring opening to give heptafulvalene (8) upon warming to room temperature.The rearrangements of 7-acetoxynorbornadiene (9), 2-diazobicyclo(3.2.0)hepta-3,6-diene (31), and 8-diazobicyclo(2.2.2)octa-2,5-dien-7-one (33) all involve cycloheptatetraene (6) intermediates.
Bicyclofulvenes, XI, On the Question of Spiroconjugation in Spiro
Riemann, Achim,Hoffmann, Reinhard W.,Spanget-Larsen, Jens,Gleiter, Rolf
, p. 1000 - 1007 (2007/10/02)
The title compound 4 as well as the derivatives 5 and 6 have been prepared.The first band in the UV spectrum of 4 in n-heptane is blue-shifted by ca. 20 nm with respect to those of 5 and 6.Model calculations with the CNDO/S-CI method indicate that this hypsochromic shift as well as the bathochromic shift of the corresponding band of 2 relative to that of 3, cannot be explained by spiroconjugation.The thermolysis of 4 yields benzene, heptafulvalene (15), and fulveneallene (16).The latter products are probably derived from cycloheptatrienylidene (14) as an intermediate.
Carbene Reactions, XIV. - Generation of Cycloheptatrienylidene by Vapor Phase Thermolysis of C7H7-Acetates
Hoffmann, Reinhard W.,Loof, Ingo H.,Wentrup, Curt
, p. 1198 - 1206 (2007/10/02)
Gas phase thermolysis at 450 deg C of 7-acetoxynorbornadiene (1) or of 7-acetoxycycloheptatriene (2) yielded acetic acid and heptafulvalene (4) indicative of the intermediate formation of cycloheptatrienylidene (3).The latter rearranged to fulveneallene (8) on thermolysis at 600 deg C.The elimination of acetic acid could involve a tropylium/acetate-ion pair since ionic processes dominate in the similar elimination of acetic acid from the tricyclic acetate 20.
