Glycomaurin and Glycomaurrol, New Carbazole Alkaloids From Glycosmis mauritiana (Rutaceae) Bark

The stem bark of Glycosmis mauritiana contained the acridone alkaloids noracronycine and des-N- methylacronycine, and two new carbazole alkaloids, 3,3,10-trimethyl-3,7-dihydropyrano[2,3-c] carbazole (glycomaurin) and 6-methyl-4-(3′-methylbut-2′-enyl)carbazol-3-ol (glycomaurrol), whose structures were confirmed by synthesis and by cyclization to dihydroglycomaurin respectively. Glycomaurin has a ring system which has not been previously found in nature.