3,7a-Diepialexine

A. Frankowski, C. Seliga, and J. Streith, Imidazole analogues of 6-epicastanospermine and of 3,7a-diepialexine, Helv. Chim. Acta, 74 (1991) 934—940. 

The imidazole derivative 31 was transformed to bicyclic analogs by selective tritylation at the nitrogen and the primary hydroxyl groups followed by benzylation and then detritylation to give 33 [71]. When the benzylation was carried out at lower temperatures followed by detritylation, the dibenzyl derivative 32 was obtained. Both 32 and 33 were readily cyclized by the action of triflic anhydride in pyridine and chloroform to give 34 and 35, respectively as imidazole analogues of 6-epicastanosperimine and 3,7a-diepialexine. 

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