Pyridyl(methyl)ketenes
Subtitle: preparation, detection and trends in reactivity.
Contributors: University of Toronto.  Dept. of Chemistry.
Published: 2004
Language: eng
Number of pages: 105
Description: Methyl substituted ketenes 17 are less reactive than their monosubstituted counterparts 14 because of steric hindrance to water attack in the ketenyl plane by the methyl group. Conversion of 3- 23 to 3-24 is unaffected by the methyl group, whereas conversion of 2- and 4-29 to 2- and 4-24, respectively, are affected by steric crowding associated by with the methyl group.2-, 3-, and 4-Pyridyl(methyl)ketenes 17 were generated by photochemical Wolff rearrangements and detected by IR spectroscopy. Generation of 17 in water by flash photolysis with detection by UV spectroscopy, revealed formation of transient species which were converted to the corresponding 2-pyridylpropanoic acids 24. 3-17 reacts with water to form the ene-diol 3-23, which tautomerises to 3-24. Hydration of 2- and 4-17 occurs by addition of water to form dihydropyridine intermediates 2- and 4-29, respectively. Proton transfer via water bridges, converts 2- and 4-29 to 2- and 4- 24, respectively.
Notes: Adviser:  Thomas T. Tidwell.

Thesis (M.Sc.)--University of Toronto, 2004.

Electronic version licensed for access by U. of T. users.

Source: Masters Abstracts International, Volume: 43-03, page: 0854.

MICR copy on microfiche (2 microfiches).