Ds. Black et al., CALIX[3]INDOLES, NEW MACROCYCLIC TRIS(INDOLYLMETHYLENE) COMPOUNDS WITH 2,7-LINKAGES, Journal of the Chemical Society, Chemical Communications, (10), 1993, pp. 819-821
A series of macrocyclic tris(indolylmethylene) compounds (calix[3]indo
les] can be obtained from 7- or 2-hydroxymethylindoles or from the com
bination of either an indole with a bis(hydroxymethyl)-2,7'-diindolylm
ethane or a bis(hydroxymethyl)indole with a 2,7'-diindolylmethane; an
isomeric series can be obtained from the combination of an indole with
a bis(hydroxymethyl)-2,2'-diindolylmethane.