Staurosporine sugar moiety

The UV 242, 291, 320, 334, 354, and 370 nm) and IR 1670 and 3400 cm ) spectra of 4 -N-methyl-5 -hydroxystaurosporine (300) were very similar to those of (+)-staurosporine (295) (see Scheme 2.74), indicating the presence of a similar indolo[2,3-fl]carbazole framework with a lactam function. The NMR spectra of 4 -N-methyl-5 -hydroxystaurosporine (300) were also very similar to those of (+)-staurosporine (295) (see Scheme 2.74), except for the difference in the substitution pattern of the sugar moiety. Thus, the H-NMR spectrum showed two shielded N-methyl singlets at 2.37 and a doublet (/=9.9Hz) for the C-5 proton at 4.43 and the C-3 singlet at 5 3.95, and a shielded doublet (/=9.9 Hz) for the C-4 proton at 5 3.02, indicating the presence of additional methyl and hydroxy groups at the C-4 N-methyl and the C-5 carbon, respectively. Based on these spectral data, and the structural similarity to (+)-staurosporine (295), the structure 300 was assigned to 4 -N-methyl-5 -hydroxystaurosporine. This structure was further supported by the C-NMR and NOESY spectra (298) (Scheme 2.75). 

The UV spectrum [7max 238, 256 (sh), 293 (sh), 314, 362 (sh), and 390 (sh) nm] of rebeccamycin (337) indicated the presence of an indolo[2,3-fl]pyrrolo[3,4-c]carbazole-5,7(6H)-dione framework. This was also discernible from its IR spectrum. The H-NMR spectrum indicated the presence of an amide NH at 8 11.37 and an indole NH at 6 10.30, in addition to signals for aromatic protons and a sugar moiety. Unlike (+)-staurosporine (295) (see Scheme 2.74), where the lactam function deshielded only the ortho C-4 proton, the C-4 and C-8 aromatic protons in rebeccamycin are both deshielded due to the anisotropic deshielding effect of the phthalimide function. 

The second group of compounds includes the protein kinase C (PKC) inhibitors, such as staurosporine and its derivatives. Usually, they contain a sugar moiety linked... 

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