Ritter reactions. II. Reductive deamidation of N-bridgehead amides.

✍ Scribed by Roger Bishop; Graham Burgess

• Book ID: 104233451
• Publisher: Elsevier Science
• Year: 1987
• Tongue: French
• Weight: 219 KB
• Volume: 28
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)81048-0

✦ Synopsis

Adam'ZltyZ- or homoadamantyl-derived N-bri&ehead amides are converted in high yields into hydrocarbon derivatives on prolonged ref7,ux in ethanol and 50% sulphuric acid (I:1 by volwne). This process probably involves A AL1 hydrolysis to the tertiary carboniwn ion, followed by hydride abstraction from the ethanol solvent.

7,11-Dimethylene-6,7,8,9-tetrahydro-5,9-propano-5H-benzocycloheptene (1) undergoes an efficient intramolecular cyclisation and Ritter reaction in the presence of 1 strong acid and acetonitrile to yield the acetamide derivative (2) . When this amide was refluxed in a mixture of ethanol and 50% sulphuric acid (1:l by volume) a less polar compound was formed slowly, the reaction being essentially complete after 46 hours. Purification of this material on alumina gave a 60% yield of a hydrocarbon product whose data 2 indicated the structure 7-methyl-6,7,8,9,10,ll-hexahydro-5,9:7,ll-dimethano-5H-benzocyclononene (3).