Synthesis of the spermidine alkaloid (±)- N-acetyl- N(1)-deoxymayfoline

Abstract

The total synthesis of the spermidine alkaloid (±)- N(1)-acetyl- N(1)-deoxymayfoline ((±)- 1) was achieved by expansion of rings. The 5-membered cyclic compound 2was fused with butadiene by intermolecular Diels-Alder cycloaddition. The resulting 7-phenyl-1,6-diazabicyclo[4.3.0]nona-3,7-dien-9-one ( 4) was reductively cleaved with Raney-Ni in alcoholic KOH to afford the mono-cyclic lactam 6. This was selectively alkylated in high yields to the cyano derivative 7. Reduction of the nitrile group to the amine derivative 8 went smoothly by use of Adam's catalyst in the presence of acid. Intramolecular transamidation was then accomplished by acid catalysis with TsOH to furnish the 13-membered diazalactam 9. The synthesis of (±)- 1 was completed by the selective acetylation of the more nucleophilic amino group.