71784-32-2Relevant academic research and scientific papers
Photocyclization of 2-(dialkylamino)ethyl acetoacetates: Remote proton transfer and stern-volmer quenching kinetics in the system involving two reactive excited states
Hasegawa, Tadashi,Yasuda, Naoko,Yoshioka, Michikazu
, p. 221 - 226 (1996)
Upon irradiation, 2-(dibenzylamino)ethyl and 2-(N-benzyl-N-methylamino)ethyl acetoacetate (1a and 1b) undergo photocyclization via remote proton transfer from the benzyl group to the acetyl carbonyl oxygen to give eight-membered azalactones. Irradiation of the corresponding (diisopropylamino)- and (dimethylamino)ethyl esters gave no azalactones. Introduction of the methyl group on C-2 of 1a brought about a complicated photoreaction, probably due to competition of α-cleavage. The Stern-Volmer plots for the photoreaction of 1a did not show the linear relationship indicating that the photoreaction proceeds from two reactive excited states. The Stern-Volmer quenching equation for the system was obtained by applying the steady-state approximation and was used for the analysis of the photoreaction of 1a. The triplet lifetime was determined to be 1.6 × 10-8 s.
Applications of Stevens [1,2]-shifts of cyclic ammonium ylides. A route to morpholin-2-ones
West,Naidu
, p. 6051 - 6056 (2007/10/02)
2-(N,N-Dialkylamino)ethyl diazoacetoacetates 2 were prepared in two steps from readily available ethanolamines 1 . When heated in the presence of catalytic Cu, the substrates cleanly formed morpholinones 3, presumably via the intermediacy of copper cathenoids and cyclic ammonium ylides. In most cases involving benzylic or allylic migrating groups, ylide [1,2]-shift occurred in good yield (55-80%). In the case of benzhydryl containing substrate 2g, only dimer 4 was isolated. Simple alkyl groups failed to undergo the rearrangement, with the exception of tert-butyl case 2i, which furnished morpholinone 3i in low yield. Substituted allylic case 21 gave only [1,2]-shift product 3l, with no evidence for competing [2,3]-shift to give 3l'. Diazoacetates 2n-p also underwent conversion to morpholinones 3n-p in 19-64% yield with Cu(acac)2 catalysis.
