Indolocarbazole glycosides

Indolocarbazole glycosides have attracted considerable interest over the years, as most indolo[2,3-fl]pyrrolo[3,4-c]carbazole alkaloids possess this structural feature. These systems are beyond the scope of this review however, there are several studies where glycosides of the parent system 1 have been investigated, in some... 

Go 6976, a non-glycosidic/non-aminoalkyl substituted indolocarbazole lactam was shown to be a potent and selective PKC inhibitor with a remarkable... 

The stereoselective glycosidation of the secoaglycon 1338 was achieved by reaction of the sodium salt of 1338 with the a-l,2-anhydrosugar 1339 to give the p-glucopyranoside 1340 in 48% yield. After the removal of the SEM protecting group with TBAF, the photocyclization of compound 1341 afforded the indolocarbazole... 

The anhydride moiety of a rebeccamycin analogue 112 (where R = glycoside) is partially or totally reduced by reaction with a zinc-mercury amalgam to give lactones 113 and indolocarbazoles 114 as a mixture of regioisomers (Equation 29) <2004BMC1955>. 

The benzannulation allows a facile incorporation of a hydrogen-bonding functionality, which complements the pharmacophore in naturally occurring indolocarbazoles. Orthogonally protected indolocarbazole nitrogen atoms allow a concise and selective glycoside formation en route to synthetic indolocarbazoles as natural product analogues. 

Danishefsky formulated a strategy to staurosporine [41], in which epoxidation of glycal (-)-98 with maleimide 97 resulted in one of the indole N-glycosidic linkages to form 99. Treatment of olefin 99 using Barton deoxygenation, iodine and f-BuOK followed by radical dehalogenation provided the pyranosylated indolocarbazole 101 with 64% yield. Deprotection and methylation followed as shown in Scheme 14 (i.e., 101—102), after which reduction of imide 102 led to a 1 1 mixture of 1 and la. 

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