A Study of some alkylidenephthalimidine derivatives

Abstract

The formation of trimethyl-1-ethylpyrrole-2,3,4-tricarboxylate (1) from 1-ethyl-2-methyleneaziridine (2) and dimethylacetylenedicarboxylate (DMAD) has been reported by Cookson et al. R.C. COOKON, B. HALTON, I.D.R. STEVENS and C.T. WATTS. J. (c) 928 (1967). The reaction is believed to proceed by addition of the acetylenic ester to the exocyclic double bond of the aziridine, followed by ring opening and then participation of the nitrogen non-bonded pair to produce the Δ3 -pyrroline derivative (3) as shown in Scheme 1. The pyrrole (4) could be formed by aromatisation of (3) but it was shown that the pyrroletricarboxylate (1) does not result from treatment of (4) with DMAD under conditions identical to those used for (2). Plausible routes for the formation of (1) from (3) have been written and involve addition of DMAD to the exocyclic double bond of (3) as shown, in part, in Scheme 2. One objective of this work was to investigate further the possibility of (3) as intermediate in this reaction scheme.