C. Gremmen et al., THE SYNTHESIS OF NEW HETEROCYCLIC BRIDGED RING-SYSTEMS - ANALOGS OF TETRAHYDRO-BETA-CARBOLINES, Tetrahedron letters, 39(11), 1998, pp. 1441-1444
New bridged beta-carbolines were synthesized via a short synthetic rou
te. The key step of the sequence is a Pictet-Spengler condensation und
er neutral conditions, employing a cyclic amine and several aldehydes.
Using 5,5-diethoxypentanal gave a bridged analog which could be furth
er ring closed to a new pentacyclic system. (C) 1998 Elsevier Science
Ltd. All rights reserved.