Synthesis and reactivity of 2-(carboxymethyl)aziridine derivatives.

Ring-opening, cycloaddition and rearrangement reactions of nitrogen-substituted cyclopropane derivatives

1,3-Dipolar cycloadditions of diazoalkanes to some nitrogen containing heteroaromatic systems

1,3-Dipolar cycloadditions of diazoalkanes to pyridazines. Asymmetric 1,3-dipolar cycloadditon of azomethine imines derived from diazoalkane-pyridazine cycloadducts

Publisher Summary This chapter reviews heterocyclic β-enamino esters and an approach on annelation of a pyrimidine ring to an existing ring. While most classical enamines and open-chain enamino esters are obtained by condensation, for example, of a secondary amine with a keto compound, heterocyclic β-enamino esters can be obtained only by special reactions, such as rearrangement or direct syntheses. Heterocyclic β-enamino esters which are dihydrofurans, dihydro-4H-pyrans, and dihydro-4H-thiopyrans are easily accessible in a special case of acyl lactone rearrangement. While oxiranes afford with sodium ethylcyanoacetate only α-cyano-γ-butyrolactone—that is, the insertion of the hydroxyethyl moiety into ethyl cyanoacetate, thiiranes give with sodium cyanoacetate, in a one-step procedure, ethyl 2-amino-4,5-dihydrothiophene-3-carboxylate and some polymeric side products. Heterocyclic β-enamino esters differ in many aspects from enamines, open-chain β-enamino esters, and heterocyclic enamines, all of which point to a specific electron distribution in their enaminocarbonyl chromophore. Particular attention is paid to spectroscopic studies of these title compounds and to the consequences of their structures, protonation behavior, tautomerism, stability, and mesomeric forms.

Yasuko Adachi

Papers

Synthesis and reactions of ethyl 3-acetyl-8-cyano-6,7-dimethylpyrrolo[1,2-a]pyrimidine-4-carboxylate and related compounds