87308-11-0Relevant academic research and scientific papers
Convergent and Efficient Synthesis of Spiro
Rosenberg, Saul H.,Rapoport, Henry
, p. 56 - 62 (2007/10/02)
A synthesis is presented of spiro, tricyclic analogues containing the A, N, and O rings of codeine.Two successive 1,4-additions into a pyridine residue, an intermolecular aryllithium addition followed by an intramolecular ester enolate ring closure, establish the spiro system.Reduction and finally α-methylene lactam rearrangment provide the necessary functionalization for further elaboration and C-ring closure.
Synthesis of 3-Methyl-5,6-dihydro-3H-benzofuroisoquinolin-7(7aH)-ones
Weller, Dwight D.,Stirchak, Eugene P.,Weller, Doreen L.
, p. 4597 - 4605 (2007/10/02)
The coupling of 2-(alkoxymethoxy)phenylcopper derivatives with the salt of ethyl chloroformate and ethyl 3-(pyridin-3-yl)propenoate was found to be an efficient method for the preparation of 4-(2-hydroxyphenyl)pyridines 13 substituted at C-3 with a propanoate side chain.N-Methylation and O-alkylation with ethyl bromoacetate gave salts 3 which when treated with base underwent an intramolecular enolate addition to the pyridinium nucleus to produce spiro 4.Prolonged base treatment of 4 yielded ethyl 3-methyl-7-hydroxy-5,7a-dihydro-3H-benzofuroisoquinoline-6-carboxylates 5 by a Dieckmann reaction.Reduction of 5 led to predominately trans-3-methylhexahydro-1H-benzofuroisoquinolin-7(7aH)-ones, while reduction of 4 and then Dieckmann cyclization yielded mainly the cis isomers.
