Aza analogs of kainoids by dipolar cycloaddition

The 1,3-dipolar cycloadditions of diazoalkanes with trans-diethyl glutaconate yield 1-pyrazolines, which isomerize to 2-pyrazolines or are oxidized to pyrazoles. The 2-pyrazolines may serve as precursors to novel glutamate analogs or aza analogs of kainoids. The regioselectivity of the 1,3-dipolar cycloadditions of diazoalkanes and trans-diethyl glutaconate and isomerization of the 1-pyrazolines to 2-pyrazolines are evaluated.