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Pyrolysis of Aryl Azides. XII. Mechanistic Implications of the Very Small Neighboring Group Effects Across the 2,3-Bond of 2-Azidonaphthalene

Pyrolysis of Aryl Azides. XII. Mechanistic Implications of the Very Small Neighboring Group... <jats:p>2-Azidonaphthalenes with nitro, acetyl, benzoyl and methoxycarbonyl substituents in the 3-position have been synthesized and then pyrolysed in nitrobenzene solution. At 120°, the rates (relative to 2-azidonaphthalene) are respectively 27.9, 24.8, 5.00 and 3.67. These very small neighbouring group effects are consistent with a transition state which has considerable quinonoid character. No evidence of cyclic products was obtained from the two azides with nitro and ester neighbouring groups. With the two azido ketones there was infrared spectroscopic evidence of clean cyclization in dilute solution, to form the corresponding naphth [2,3-c] isoxazole. Our attempts to isolate these two naphthisoxazoles led to decomposition, though 3-methylnaphth[2,3-c] isoxazole has been reported previously ( Friedrichsen and Kaschner 1977). </jats:p> http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Australian Journal of Chemistry CrossRef

Pyrolysis of Aryl Azides. XII. Mechanistic Implications of the Very Small Neighboring Group Effects Across the 2,3-Bond of 2-Azidonaphthalene

Australian Journal of Chemistry , Volume 47 (6): 1031 – Jan 1, 1994

Pyrolysis of Aryl Azides. XII. Mechanistic Implications of the Very Small Neighboring Group Effects Across the 2,3-Bond of 2-Azidonaphthalene


Abstract

<jats:p>2-Azidonaphthalenes with nitro, acetyl, benzoyl and methoxycarbonyl substituents in the 3-position have been synthesized and then pyrolysed in nitrobenzene solution. At 120°, the rates (relative to 2-azidonaphthalene) are respectively 27.9, 24.8, 5.00 and 3.67. These very small neighbouring group effects are consistent with a transition state which has considerable quinonoid character. No evidence of cyclic products was obtained from the two azides with nitro and ester neighbouring groups. With the two azido ketones there was infrared spectroscopic evidence of clean cyclization in dilute solution, to form the corresponding naphth [2,3-c] isoxazole. Our attempts to isolate these two naphthisoxazoles led to decomposition, though 3-methylnaphth[2,3-c] isoxazole has been reported previously ( Friedrichsen and Kaschner 1977). </jats:p>

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Publisher
CrossRef
ISSN
0004-9425
DOI
10.1071/ch9941031
Publisher site
See Article on Publisher Site

Abstract

<jats:p>2-Azidonaphthalenes with nitro, acetyl, benzoyl and methoxycarbonyl substituents in the 3-position have been synthesized and then pyrolysed in nitrobenzene solution. At 120°, the rates (relative to 2-azidonaphthalene) are respectively 27.9, 24.8, 5.00 and 3.67. These very small neighbouring group effects are consistent with a transition state which has considerable quinonoid character. No evidence of cyclic products was obtained from the two azides with nitro and ester neighbouring groups. With the two azido ketones there was infrared spectroscopic evidence of clean cyclization in dilute solution, to form the corresponding naphth [2,3-c] isoxazole. Our attempts to isolate these two naphthisoxazoles led to decomposition, though 3-methylnaphth[2,3-c] isoxazole has been reported previously ( Friedrichsen and Kaschner 1977). </jats:p>

Journal

Australian Journal of ChemistryCrossRef

Published: Jan 1, 1994

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