262842-06-8Relevant articles and documents
Direct observation of a carbene-pyridine ylide by matrix IR spectroscopy. Rearrangements of 2-pyridylacylcarbenes
Kuhn, Arvid,Plueg, Garsten,Wentrup, Curt
, p. 1945 - 1948 (2000)
FVT of 2-(2-diazoacetyl)pyridine (1) yields 2-pyridylketene (3) (largely in the s-Z form 3Z), which dimerizes to quinazolinone 5. Matrix photolysis of 1 (largely in the EZ form 1EZ) yields the carbene-pyridine ylide 6, which on further photolysis at λ > 320 nm is converted to (mainly) the s-E ketene 3E. Continued photolysis of 3E at 320 nm converts it to 3Z, and this process is reversed on photolysis at 254 nm.
Observable azacyclobutenone ylides with antiaromatic character from 2-diazoacetyl-azaaromatics
Fu, Nanyan,Allen, Annette D.,Kobayashi, Shinjiro,Sequeira, Pearl A.,Shang, Muhong,Tidwell, Thomas T.,Mishima, Masaaki
, p. 6210 - 6215 (2007)
Azacyclobutenone ylides 2 and 11 were generated in solution by laser flash photolysis of 2-diazoacetylpyridine (1) and 3-diazoacetylpyridazine (10), respectively, together with the corresponding ketenes. The ylides were identified by their characteristic IR and UV spectra: 2, ν (CH3CN) 1725 cm-1, λmax 360 and 550 (br) nm; 11, ν (CH3CN) 1776 cm-1, λmax 370 and 550 (br) nm. 2-Triisopropylsilyldiazoacetylpyridine 20 upon photolysis at 5°C in CH3CN forms the ylide 21 as a rather persistent (T1/2 2 h at 25°C) purple solution, ν (CH3CN) 1718 cm-1z, λmax 245, 378 and 546 (br) nm, but no ketene is observed. Quinolyl ylide 14 and pyridyl ylides 17 and 19 with Me and 2-pyridyl substituents, respectively, with characteristic IR and UV spectra were also generated. The 1H NMR spectrum of the pyridyl ring of 21 shows substantial upfield shifts relative to those of 20. Calculated nucleus-independent chemical shifts (NICS) for 2, 11, and 21 are comparable to those for benzocyclobutadiene (22) and benzocyclobutenone enolate (23), with substantial positive values for the 4-membered rings, while the NICS values for the 6-membered rings are significantly more positive than for benzene or pyridine. Significant bond alternation is also found in the calculated ylide structures, and these results suggest strong antiaromatic character for the 4-membered rings of 2, 11, 14, 17, 19, and 21, and greatly reduced aromatic character for the 6-membered rings.
Amination of pyridylketenes: Experimental and computational studies of strong amide enol stabilization by the 2-pyridyl group
Acton, Austin W.,Allen, Annette D.,Antunes, Luis M.,Fedorov, Andrei V.,Najafian, Katayoun,Tidwell, Thomas T.,Wagner, Brian D.
, p. 13790 - 13794 (2007/10/03)
Laser flash photolyses of 2-, 3-, and 4-diazoacetylpyridines 8 give the corresponding pyridylketenes 7 formed by Wolff rearrangements, as observed by time-resolved infrared spectroscopy, with ketenyl absorptions at 2127, 2125, and 2128 cm-1, re
