F. Felluga et al., REARRANGEMENT AND AROMATIZATION OF THE KETOENAMINE ADDUCTS FROM DIBENZOYLDIAZENE AND SECONDARY ALPHA-KETOENAMINES AND BETA-KETOENAMINES, Gazzetta chimica italiana, 127(1), 1997, pp. 31-35
The reaction of secondary alpha-ketoenamines 10 with dibenzoyldiazene
(DBD) furnish exclusively the corresponding enamine type adducts 11, w
hich rearrange at 80 degrees C in acidic medium to the more stable ena
minone isomers 12. Secondary beta-ketoenamines 14 react with the same
electrophilic diazene only at 80 degrees C to give the open-chain addu
cts 15, which undergo aromatization under prolonged heating to the phe
nol derivatives 16. The presence of 1,3,4-oxadiazine derivatives could
not be observed.