Heptafulvenone, Vinylketene, Butadienylketene, and Allenylketene − Facile Generation, Observation, and Radical Reaction with TEMPO
摘要:
Heptafulvenone (1), vinylketene (11), 1,3-butadienylketene [(E)-15], and allenylketene (21) have been prepared by reaction of the corresponding acyl chlorides with 1,8-bis(dimethylamino)naphthalene as long-lived species in solution at room temperature, and their ketenyl IR bands observed under these conditions for the first time, at 2101, 2118, 2111, 2117 cm(-1), respectively. These unsaturated ketenes react with tetramethylpiperidinyloxyl (TEMPO, TO.) with initial attack at the carbonyl carbon giving delocalized radicals which give from 1 a mixture of the ring contracted o-, m-, and p-formylbenzoates O=CHC6H4CO2T (6) and the bis(cycloheptatrienyl) dimer 7. The products from 11, (E)-15, and 21 are the bis(TEMPO) adducts. (E,Z)-TOCH2CH= CHCO2T (12), (E,E)-TOCH2CH=CHCH=CHCO2T (17), and (E,Z)-CH2=C(OT)CH=CHCO2T (22), respectively.
Neutralization-reionization study of C6H6O isomers
作者:Frantisek Turecek、Donald E. Drinkwater、Andre Maquestiau、Fred W. McLafferty
DOI:10.1002/oms.1210240825
日期:1989.8
AbstractNeutralization‐reionization (+NR+) mass spectrometry is employed to examine the behavior of C6H6O isomers in the gas phase. Phenol and cyclohexa‐2,4‐dienone are found not to interconvert following neutralization with mercury of their corresponding cation radicals at 9.9 keV kinetic energy. A very low extent of isomerization is observed following collisional activation of fast C6H6O neutrals with helium. The +NR+ and collisionally activated dissociation spectra, the latter obtained at unit mass resolution, are used to identify these [C6H6O]+ ˙ isomers. Hexa‐1,3,5‐trienal is found to cyclize spontaneously to cyclohexa‐2,4‐dienone during attempted pyrolytic preparation. The thermochemistry of these C6H6O molecules and cation radicals is discussed on the basis of experimental data and MNDO calculations.