The Pyrolysis of Butatrienone Precursors: 3,4-Diazatricyclo[5.2.1.02,6]deca-3,8-diene-endo-cis-2,6-dicarboxylic anhydride and Its 5,5-Diphenyl Derivative

1990 ◽  
Vol 43 (3) ◽  
pp. 549 ◽  
Author(s):  
MR Anderson ◽  
RFC Brown ◽  
NR Browne ◽  
FW Eastwood ◽  
GD Fallon ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Infrared Spectroscopy ◽  
Matrix Isolation ◽  
Argon Matrix ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Flash vacuum pyrolysis of the title anhydride (4) gave a poor yield of butatrienone , detected by argon matrix isolation infrared spectroscopy. Similar pyrolysis of the 5,5-diphenyl derivative (8) failed to give diphenylbutatrienone ; the red product (16) is considered to have been formed by dimerization of an intermediate 2H-indenylidenemethanone (15). The crystal structure of (16) has been determined.

Pyridyl- and Pyridylperoxy Radicals – A Matrix Isolation Study

2014 ◽  
Vol 67 (9) ◽  
pp. 1324 ◽  
Author(s):  
André Korte ◽  
Artur Mardyukov ◽  
Wolfram Sander
Keyword(s):  
Density Functional Theory ◽  
Infrared Spectroscopy ◽  
Density Functional ◽  
Matrix Isolation ◽  
Ring Expansion ◽  
Peroxy Radicals ◽  
Functional Theory ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Good Agreement

The three isomeric pyridyl radicals 2a–c were synthesised using flash vacuum pyrolysis in combination with matrix isolation and characterised by infrared spectroscopy. The IR spectra are in good agreement with spectra calculated using density functional theory methods. The reaction of the pyridyl radicals 2 with molecular oxygen leads to the formation of the corresponding pyridylperoxy radicals 3a–c. The peroxy radicals 3 are photolabile, and irradiation results in syn–anti isomerisation of 3a and 3b and ring expansion of all three isomers of 3.

ChemInform Abstract: Detection by infrared Spectroscopy of Benzyne Formed by Flash Vacuum Pyrolysis and Trapped in an Argon Matrix.

1986 ◽  
Vol 17 (25) ◽  
Author(s):  
R. F. C. BROWN ◽  
N. R. BROWNE ◽  
K. J. COULSTON ◽  
L. B. DANEN ◽  
F. W. EASTWOOD ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Argon Matrix ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Conformational behaviour, photochemistry and flash vacuum pyrolysis of a 2-(1H-tetrazol-1-yl)thiophene

2017 ◽  
Vol 41 (24) ◽  
pp. 15581-15589 ◽  
Author(s):  
Maria I. L. Soares ◽  
Cláudio M. Nunes ◽  
Clara S. B. Gomes ◽  
Teresa M. V. D. Pinho e Melo ◽  
Rui Fausto
Keyword(s):  
Infrared Spectroscopy ◽  
Low Temperature ◽  
Theoretical Calculations ◽  
Matrix Isolation ◽  
Flash Vacuum Pyrolysis ◽  
Fused Heterocycles ◽  
Vacuum Pyrolysis ◽  
Temperature Matrix ◽  
Photochemical Behaviour

The conformational and photochemical behaviour of a 2-(1H-tetrazol-1-yl)thiophene was studied using low-temperature matrix isolation infrared spectroscopy and theoretical calculations. FVP of 2-(1H-tetrazol-1-yl)thiophene afforded new thieno-fused heterocycles.

Synthesis of Dimethylbutatrienone, (CH3)2C=C=C=C=O, by a Rearrangement-Fragmentation Process and by Direct Elimination

1991 ◽  
Vol 44 (1) ◽  
pp. 87 ◽  
Author(s):  
RFC Brown ◽  
KJ Coulston ◽  
FW Eastwood ◽  
MJ Irvine
Keyword(s):  
Infrared Spectroscopy ◽  
Acid Chloride ◽  
Fragmentation Pathway ◽  
Dienoic Acid ◽  
Fragmentation Process ◽  
Mixed Anhydride ◽  
Argon Matrix ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Derivatives Of

4-Methylpenta-1,2,3-trien-1-one ( dimethylbutatrienone , Me2C=C=C=C=O) was generated by flash vacuum pyrolysis of precursors derived from 4,4-dimethyl-2-oxotetrahydrofuran-3-ylideneacetic acid (6) and from 4-methylpenta-2,3-dienoic acid (14). Pyrolysis of the mixed trifluoroacetic anhydride and of the acid chloride of (6) and, in poorer yield, of (14) gave 4-methylpenta-1,2,3-trien-1-one which was detected by argon matrix infrared spectroscopy (Vmax 2224, 2216 cm-1) and by reaction with methanol to form methyl 4-methylpenta-2,3-dienoate. The fragmentation pathway for the derivatives of (6) was established by detection of the initially formed propadienone, 4,4-dimethyl-2-oxotetrahydrofuran-3-ylideneethenone, and also by pyrolysis of the trifluoroacetic mixed anhydride (7.L) and the acid chloride (8-L) of 4,4-dimethyl-2-oxotetrahydro(2-13C)furan-3-ylideneacetic acid. The argon matrix spectra of pyrolysates from (7-L) and (8-L) showed bands at 2182 and 2177cm-1 attributed to 4-methyl(1-13C)penta-1,2,3-trien-1-one. 4,4-Dimethyl-3-methylenedihydrofuran-2-one was prepared in 67% yield by flash vacuum pyrolysis of the acid (6).

Unexpected Pyrolytic Behaviour of Substituted Benzo[c]thiopyran and Thieno[2,3-c]thiopyran S,S-dioxides

2014 ◽  
Vol 67 (9) ◽  
pp. 1288 ◽  
Author(s):  
R. Alan Aitken ◽  
Clémence Hauduc ◽  
M. Selim Hossain ◽  
Emily McHale ◽  
Adrian L. Schwan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Hydrogen Atom Transfer ◽  
Membered Ring ◽  
X Ray ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Higher Temperature ◽  
Intramolecular Hydrogen ◽  
Carbonyl Products

Flash vacuum pyrolysis (FVP) of benzo[c]thiopyran S,S-dioxide (1) results in formation of indene and 2-vinylbenzaldehyde as previously described. A range of eight analogues with various substitution patterns are found to behave differently. In general, there is no extrusion of SO2 to give products analogous to indene, but unsaturated carbonyl products analogous to 2-vinylbenzaldehyde are formed in most cases by way of ring expansion to a 7-membered ring sultine, extrusion of SO, and intramolecular hydrogen atom transfer. Other processes observed include formation of anthracene via an isomeric 7-membered sultine with loss of SO, CO and methane or butane, and formation of 4-ethylidene-4,5-dihydrocyclobuta[b]thiophenes by way of SO loss, a radical rearrangement, and extrusion of acetone. The analogues with a halogen substituent at position 8 on the benzene ring require a higher temperature to react and give naphthalene resulting from net elimination of HX and SO2. The X-ray crystal structure of 1 is also reported.

Flash Vacuum Pyrolysis and Photolysis of 3,3,5,5-Tetramethylpyrazolin-4-one - A Matrix Isolation Study

2000 ◽  
Vol 2000 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Wolfram Sander ◽  
Roman Wrobel ◽  
Peter Komnick ◽  
Paul Rademacher ◽  
Heidi M. Muchall ◽  
...  
Keyword(s):  
Matrix Isolation ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Detection by infrared spectroscopy of benzyne formed byflash vacuum pyrolysis and trapped in an argon matrix

1986 ◽  
Vol 27 (9) ◽  
pp. 1075-1078 ◽  
Author(s):  
Roger F.C. Brown ◽  
Neil R. Browne ◽  
Karen J. Coulston ◽  
Louisa B. Danen ◽  
Frank W. Eastwood ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Argon Matrix ◽  
Vacuum Pyrolysis

The 1,2-Didehydronaphthalene to 1H-Indenylidenecarbene Rearrangement: Formation of 7-Methyl-1H-Indenylideneethenone and Its Rearrangement to Acenaphthylen-4-Ol in a Flash Vacuum Pyrolytic Reaction

1987 ◽  
Vol 40 (10) ◽  
pp. 1687 ◽  
Author(s):  
RFC Brown ◽  
KJ Coulston ◽  
BJ Dobney ◽  
FW Eastwood ◽  
GD Fallon
Keyword(s):  
Crystal Structure ◽  
Trifluoroacetic Anhydride ◽  
X Ray ◽  
Flash Vacuum Pyrolysis ◽  
Ethanoic Acid ◽  
Vacuum Pyrolysis ◽  
Pyrolytic Reaction ◽  
E And Z Isomers

7-Methyl-1 H- indenone was trapped as the cyclopentadiene adduct endo* 8-methyl-1,4,4a,9a tetrahydro-1,4-methano-9H-fluoren-9-one (11) which was converted into the E- and Z-isomers (15) and (16) of endo (8'-methyl-l',4',4a',9a'-tetrahydro-1',4'-methano-9'H-fluoren-9'-ylidene) ethanoic acid by addition of methoxyethyne, rearrangement and hydrolysis. Both acids yielded the anhydride (17) of the E-acid on treatment with trifluoroacetic anhydride. Flash vacuum pyrolysis of this anhydride at 650� gave acenaphthylen-4-ol. 7-Methyl-1 H- indenylideneethenone (7) is proposed as an intermediate in this reaction and the results are discussed in relation to the rearrangement described in the title. The X-ray crystal structure of methyl endo (E)-(8'-methyl-l',4',4a',9a'-tetrahydro-l',4'-methano-9'H-fluoren-9'-ylidene) ethanoate (13) is reported.

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