The 1,3-dipolar cycloaddition of 2-diazopropane 1 with the N-substitued maleimides 2a-b at 0°C. has led to monoadducts Δ2-pyrazolines 3a-b. On the other hand the same reaction is carried out under similar operating conditions with maleimide 2c, has led to a new and unexpected heterocyclic structure 4c next to Δ2-pyrazolines. The photolysis of 3a-c has led to a cyclopropylketones 5a-c.
N. Ben Hamadi, J. Lachheb, A. Khemiss
2-diazopropane, Δ2-pyrazoline, photochemistry, cyclopropylketone