1,3-dipolar cycloaddition of 2-diazopropane on coumarine 2 done at 0°C leads to the corresponding pyrazoline 3. The oxidation of 3 by MnO2 led to the pyrazolenine 4. On the other hand, the same reaction is carried out under similar operating conditions with 2-arylidenindane-1,3-diones 5a-d, leading to a new and unexpected heterocyclic structures 6a-d.
M. Askri, N. Ben Hamadi, M. Msaddek, M.E. Rammah
2-diazopropane, oxydation, Δ2-pyrazoline, spiro-Δ3-(1,3,4)-oxadiazoline