Pyrrolo isoquinoline alkaloid

Several tetra- and pentacyclic systems were prepared from Pro, which was first -substituted with naphthalene or phenanthrene rings whereupon the cyclization took place. Such reactions were used for synthetic ap-proaehes toward alkaloids vinceten from Cynachum vincetoxicum (the tetrahydrobenzo /]pyrrolo[l,2-Z ]isoquinoline system 146) (79LA1212 84AJC819) or tylophorine (65T2573). 

The improved synthesis of an antipsychotic pyrrolo[2,3-g]isoquinoline from an areca alkaloid shown in Scheme 3 <84JOC5109> began with a condensation of arecolone with dimethyl or diethyl malonate to give diketone (49). This diketone could be isolated and characterized as either the hydrochloride salt or the free base but was more conveniently subjected in crude form to Knorr... 

Lamellarins belong to a new dass of hexacyclic alkaloids including a pyrrole and an isoqtunoline the nitrogen atom is common to the two rings. Lamellarins are derived from pyrrolo[2-l,a]isoquinoline or pyrrolo[2-l,a]dihydroisoqui-noline according to the degree of unsaturation of the 5-6 bond. 

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