Synthetic routes to pyrrolizine-1,5-dione derivatives by flash vacuum pyrolysis of amidomethylene derivatives of Meldrum's acid.
Methoxymethylene Meldrum's acid 1 reacts with 5- and 6-membered lactams in refluxing acetonitrile to give the N-substituted products 9-15. If the reactions are continued for extended times, the Meldrum's acid derivatives decompose to provide enamidoesters e.g. 22-24. Flash vacuum pyrolysis of the 5-membered ring products 9-13 provides reasonable yields of the fused pyrrolones 31-35. The constitution of the products is supported by X-ray crystal structures of 10, 12, 19, 32 and 34.
McNab
Hamish
H
School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh, UK EH9 3JJ. H.McNab@ed.ac.uk
Morrow
Mark
M
Parsons
Simon
S
Shannon
David A
DA
Withell
Kirsti
K
D000097:Acetonitriles / Q000737:chemistry; D018360:Crystallography, X-Ray; D004146:Dioxanes / Q000737:chemistry*; D007769:Lactams / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D014618:Vacuum
D000097:Acetonitriles; D004146:Dioxanes; D007769:Lactams; D011758:Pyrroles; C076489:Meldrum's acid; C032159:acetonitrile