Kasturi, Tirumalai Rangachar and Krishnan, Lalitha and Prasad, Ramanujam Srinivasa (1982) Amide-catalysed isomerisation of 5,6-dihydroisoquinolines: a novel synthesis of 1,2-dihydroisoquinolines. In: Perkin Transactions 1 (1). pp. 63-68.
article.1.pdf - Published Version
Restricted to Registered users only
Download (777Kb) | Request a copy
Knoevenagel condensation of 2-acylcyclohexanones or 2-ethoxycarbonylcyclohexanone with either cyanoacetamide or malononitrile followed by silver salt alkylation gave the 5,6,7,8-tetrahydroisoquinolines (3a–i). Chromic acid oxidation of the 5,6,7,8-tetrahydroisoquinolines (3a–i) to the corresponding tetralones (4a–i) followed by sodium borohydride reduction and p-toluenesulphonic acid-catalysed dehydration of the resulting alcohols (5a–i) gave the 5,6-dihydroisoquinolines (6a–i). Reaction of 5,6-dihydroisoquinolines (6a–g) with potassium amide in liquid ammonia gave a mixture of the 1,3-dihydroisoquinolines (7a–g) and the isoquinolines (8a–g). The C-1 unsubstituted 1,2-dihydroisoquinoline (7c) was found to be very unstable. In the case of the 5,6-dihydroisoquinolines (6h and 6i), reaction of potassium amide in liquid ammonia resulted in a mixture of 1-aminoisoquinoline (9) and the isoquinolines (8h and 8i). All the above compounds have been characterised by spectral data. A probable pathway for the formation of the 1,2-dihydroisoquinolines (7a–g) and the isoquinolines (8a–i) is suggested.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Royal Society of Chemistry|
|Department/Centre:||Division of Chemical Sciences > Organic Chemistry|
|Date Deposited:||01 Oct 2009 11:00|
|Last Modified:||19 Sep 2010 05:47|
Actions (login required)