Open AccessThe dipolar cycloaddition of methyl acrylate to 5,6‐diethyl‐1‐methyl‐3‐oxidopyrazinium
Author(s) -
Helliwell Madeleine,
You Yun,
Joule John A.
Publication year - 2006
Publication title -
acta crystallographica section e
Language(s) - English
Resource type - Journals
ISSN - 1600-5368
DOI - 10.1107/s1600536806017107
Subject(s) - methyl acrylate , cycloaddition , 1,3 dipolar cycloaddition , acrylate , chemistry , medicinal chemistry , organic chemistry , polymer , catalysis , monomer , copolymer
5,6‐Diethylpyrazin‐2‐one reacts with iodomethane to give a quaternary salt, deprotonation of which, in situ , liberates a 3‐oxidopyrazinium which undergoes a 1,3‐dipolar cycloaddition with methyl acrylate to form methyl ( Z )‐5‐ethyl‐4‐ethylidene‐8‐methyl‐2‐oxo‐3,8‐diazabicyclo[3.2.1]octane‐6‐ endo ‐6‐carboxylate. The crystal structure revealed (i) the existence of the imine product as its enamine tautomer, (ii) the Z geometry of the exocyclic double bond, and (iii) the endo orientation of the ester group. Pairwise hydrogen bonding between the NH H atom and the amide carbonyl group links the molecules into centrosymmetric dimers.