FURTHER STUDY ON THE TRANSFORMATION OF BETA-(1-HYDROXYBUT-3-ENYL)INDOLES INTO 1-BETA-(INDOLYL)BUTA-1,3-DIENE, YUEHCHUKENE, MURRAPANINE AND ANALOGS

beta(1-Hydroxybut-3-enyl)indoles have been converted into three indole natural products: yuehchukene 1, beta-(dehydroprenyl)indole 2, murrap anine 3 and other analogues in a one step procedure under various acid -catalysed reaction conditions in THF. A one-pot synthesis of bisnoryu ehchukene 15 starting from indole-3-carboxaldehyde was also achieved u sing a similar approach. beta(1-Hydroxybut-3-enyl)indoles are presumed to be dehydrated to 1-(beta-indolyl)buta-1,3-dienes which then react further to give yuehchukene, murrapanine and other derivatives via a D iels-Alder pathway. The yields of 3 and normurrapanine 31 could be imp roved by using an aerial oxidation method. Murrapanine and analogues w ere found to exhibit potent cytotoxicity towards various cancer cell l ines.