Flash Vacuum Pyrolysis of [2,3-13C2]Triphenylene-2,3-dicarboxylic Anhydride: Formation of Labelled Cyclopent[hi]acephenanthrylene and Triphenylene

1997 ◽  
Vol 50 (12) ◽  
pp. 1183 ◽  
Author(s):  
Roger F. C. Brown, ◽  
Karen J. Coulston ◽  
Frank W. Eastwood
Keyword(s):  
Major Product ◽  
Principal Product ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Flash vacuum pyrolysis (f.v.p.) of [2,3-13C2]triphenylene-2,3-dicarboxylic anhydride (c. 22·5% 13C2) at 950°C gave a pyrolysate which was analysed by 13C n.m.r. spectroscopy. The principal product was [2,3-13C2]triphenylene. The second major product was a 1 : 2 : 1 mixture of [4,7- 13C2]-, [4,6-13C2]- and [5,6-13C2]-cyclopent[hi]acephenanthrylene.

Some reactions of 2-ethenyl-4,4-Ethylenedioxy-1-methylcyclohex-1-ene prepared by pyrolysis of 5,5-Ethylenedioxy-7a-methyl-4,5,6,7-tetrahydro-2H-inden-1(7aH)-one

1984 ◽  
Vol 37 (11) ◽  
pp. 2295 ◽  
Author(s):  
RFC Brown ◽  
GL Burge ◽  
DJ Collins
Keyword(s):  
High Pressures ◽  
Preparative Thin Layer Chromatography ◽  
Major Product ◽  
Diels Alder ◽  
Lewis Acid Catalysts ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Layer Chromatography ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Flash vacuum pyrolysis of 5,5-ethylenedioxy-7a-methyl-4,5,6,7-tetrahydro-2H-inden-1(7aH)-one (2) at 630� gave a good yield of 2-ethenyl-4,4-ethylenedioxy-1-methylcyclohex-1-ene (6), but at 740� p-cresol was the major product. The diene acetal (6) was also obtained by pyrolysis of 5,5-ethylene- dioxy-lβ-hydroxy-7a-methyl-1,2,5,6,7,7a-hexahydro-4H-indene-1α-carbonitrile (3) at 600�. Pyrolytic reactions of 7a-methyl-2,3,7,7a-tetrahydro-1H-indene-1,5(6H)-dione (1), 5,5-ethylenedithio-7a- methyl-2,3,5,6,7,7a-hexahydro-1H-inden-1-one (7) and of 1,1-ethylenedioxy-3,5,5-trimethylcyclohex- 3-ene (8) are also described. Mild hydrolysis of the diene acetal (6) afforded 3-ethenyl-4-methylcyclohex-3-en-1-one (9) which upon brief treatment with dry hydrogen chloride in chloroform at 0� gave, after preparative thin-layer chromatography, a low yield of pure 3-ethenyl-4-methylcyclohex-2-en-1-one (11). The diene acetal (6) failed to undergo Diels-Alder reactions, even at high pressures with Lewis acid catalysts, and it reacted anomalously with two molecules of 4-phenyl-1,2,4-triazoline-3,5-dione; the isomeric diene acetal 1-ethenyl-3,3-ethylenedioxy-6-methylcyclohex-1-ene (18) gave the expected Diels-Alder adduct with this reagent.

Pinching group stabilization. The synthesis and thermal isomerization of 10-Oxapentacyclo[6.3.2.13,6.01,8.02,7]tetradeca-4,12-diene

1984 ◽  
Vol 37 (6) ◽  
pp. 1293 ◽  
Author(s):  
DN Butler ◽  
RA Russell ◽  
RB Waring ◽  
RN Warrener
Keyword(s):  
Cyclic Ether ◽  
Major Product ◽  
The Novel ◽  
Lithium Aluminium Hydride ◽  
Group Effect ◽  
Flash Vacuum Pyrolysis ◽  
Lithium Aluminium ◽  
Vacuum Pyrolysis ◽  
Site Selective ◽  
Dimethyl Benzene

Sensitized irradiation (benzophenone, 0�, N2, pyrex filter, medium pressure Hg lamp) of dimethyl tricyclo[4.2.1.02,5]nona-3,7-diene-3,4-dicarboxylate (11) in (E)-1,2-dichloroethene yielded a mixture of 1 : 1 adducts (13) and (14) by site selective [2 π+2 π] cycloaddition at the cyclobutene π-bond. Reduction of the (Z)-dichloro isomer(13) with lithium aluminium hydride formed the related diol (16) which is the immediate precursor to the cyclic ether (18). Dechlorination of (18) with zinc in ethanol forms the title diene (19). Thermolysis of the polycyclic diester (20) affords the fragmentation products cyclopentadiene and dimethyl benzene-1,4-dicarboxylate. In contrast, the title compound (19) containing the cyclic ether ring was more stable and yielded the novel isomer (28) as the major product only upon flash vacuum pyrolysis at 560�(1.5 × 10-2 Torr). This difference in behaviour is attributed to a pinching group effect exerted by the cyclic ether present in (19).

The Pyrolysis of Phenylnaphthalenedicarboxylic Anhydrides: Products of Ring Contraction and of Radical Cyclization

1990 ◽  
Vol 43 (7) ◽  
pp. 1137 ◽  
Author(s):  
MR Anderson ◽  
RFC Brown ◽  
KJ Coulston ◽  
FW Eastwood ◽  
A Ward
Keyword(s):  
Major Product ◽  
Radical Cyclization ◽  
Diels Alder ◽  
Ring Contraction ◽  
Step Process ◽  
Flash Vacuum Pyrolysis ◽  
Cyclization Process ◽  
Vacuum Pyrolysis ◽  
One Step

Naphthalene-1,2,-dicarboxylic anhydrides with neighbouring phenyl substituents give on flash vacuum pyrolysis (850-900°/0.02-0.04 mm) ring-contracted carbenes which insert into the phenyl groups. The 8- phenyl anhydride (7) gives acephenanthrylene (10) as the major product, and the 3-phenyl anhydride (15) gives 1,2 : 4,5-dibenzopentalene (indeno [2,1-a]indene) (18). The anhydrides (7) and (15) were � synthesized by pyrolysis of the corresponding 1-naphthylmethyl propynoates (2) and (13) through a new one-step process of intramolecular Diels -Alder addition/retro-Diels -Alder elimination of acetylene. 1-Phenylnaphthalene-2,3-dicarboxylic anhydride (19) on pyrolysis at 960°/0.02 mm gives fluoranthene (11) as the major product. The behaviour of the 1-C6D5 compound (24) suggests involvement of a radical cyclization process.

Sulfonyl isocyanides RSO2NC

2017 ◽  
Author(s):  
Curt Wentrup ◽  
Horst Briehl
Keyword(s):  
Ir Spectrum ◽  
Reaction Conditions ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Flash vacuum pyrolysis (FVP) of 5-azido-1-aryltetrazoles results in triple N<sub>2</sub> elimination and formation of aryl isocyanides RNC, which rearrange in part to aroylnitriles RCN under the reaction conditions. Similar FVP of 5-azido-1-arenesulfonyltetrazoles generates a compound absorbing in the IR spectrum (77 K) at 2090 cm<sup>-1 </sup>and assigned the structure of arenesulfonyl isocyanide, ArSO<sub>2</sub>NC <b>11</b>. FVP at temperatures above 600 <sup>o</sup>C results in progressively more nitrile ArSO<sub>2</sub>CN <b>12</b>. Compound <b>11</b> also disappears on warming above -80 <sup>o</sup>C

Sulfonyl isocyanides RSO2NC

2017 ◽  
Author(s):  
Curt Wentrup ◽  
Horst Briehl
Keyword(s):  
Ir Spectrum ◽  
Reaction Conditions ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Flash vacuum pyrolysis (FVP) of 5-azido-1-aryltetrazoles results in triple N<sub>2</sub> elimination and formation of aryl isocyanides RNC, which rearrange in part to aroylnitriles RCN under the reaction conditions. Similar FVP of 5-azido-1-arenesulfonyltetrazoles generates a compound absorbing in the IR spectrum (77 K) at 2090 cm<sup>-1 </sup>and assigned the structure of arenesulfonyl isocyanide, ArSO<sub>2</sub>NC <b>11</b>. FVP at temperatures above 600 <sup>o</sup>C results in progressively more nitrile ArSO<sub>2</sub>CN <b>12</b>. Compound <b>11</b> also disappears on warming above -80 <sup>o</sup>C

Flash Vacuum Pyrolysis of Isoxazoles, Pyrazoles and Related Compounds

2004 ◽  
Vol 8 (12) ◽  
pp. 1071-1088 ◽  
Author(s):  
G. Yranzo ◽  
E. Moyano
Keyword(s):  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Related Compounds

Preparation of furanoradialene by the flash vacuum pyrolysis of diesters of 3,4-bis(hydroxymethyl)-2,5-dimethylfuran

1984 ◽  
Vol 106 (26) ◽  
pp. 8197-8201 ◽  
Author(s):  
Walter S. Trahanovsky ◽  
Timothy J. Cassady
Keyword(s):  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

The Pyrolytic Rearrangement of 1-Alkynoyl-3-methylpyrazoles: Synthesis of Pyrazolo[1,5-a]pyridin-5-ols and Related Compounds

1994 ◽  
Vol 47 (6) ◽  
pp. 991 ◽  
Author(s):  
RFC Brown ◽  
FW Eastwood ◽  
GD Fallon ◽  
SC Lee ◽  
RP Mcgeary
Keyword(s):  
Carbon Chain ◽  
Ring Structure ◽  
High Yield ◽  
Methyl Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Fused Ring ◽  
Related Compounds

Flash vacuum pyrolysis of 1-(alkyn-2′-oyl)-3-methylpyrazoles at 650°/0.03 mm forms pyrazolo[1,5-a]pyridin-5-ols, often in high yield, which may bear substituents at C2, C3 or C7. In the absence of a 3-methyl group in the precursor, N-ethynylpyrazoles are formed in low yield. The formation of both types of product is interpreted as involving 3-(N-pyrazolyl)propadienones formed by N1 → N2 migration of the N-alkynoyl group with inversion of the three-carbon chain. The fused-ring structure of 2-methylpyrazolo[1,5-a]pyridin-5-ol (25) was established by X-ray crystallography of the O-benzoyl derivative (27).

Preparation of benzocyclobutenes by flash vacuum pyrolysis

1978 ◽  
Vol 19 (46) ◽  
pp. 4569-4572 ◽  
Author(s):  
Peter Schiess ◽  
Markus Heitzmann ◽  
Suzanne Rutschmann ◽  
René Stäheli
Keyword(s):  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis

Enones with strained double bonds. 10. Use of flash vacuum pyrolysis to obtain bicyclo[3.3.1]non-1-en-3-one

1987 ◽  
Vol 52 (12) ◽  
pp. 2474-2481 ◽  
Author(s):  
Kay Ann Campbell ◽  
Herbert O. House ◽  
Bruce W. Surber ◽  
Walter S. Trahanovsky
Keyword(s):  
Double Bonds ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis
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