Isatines-based small molecules represent an important product scaffold cluster by virtue of
their bioactivity and as intermediates for generating further molecular complexity including
natural ones. As the vital roles played by sugars in biological systems continue to be unravelled,
the demand for chemically pure and defined carbohydrate constructs needed to understand
structure-function relationships will remain high. Early, reported the isolation of the alkaloids -
Convolutamydine A, B, and C from Bryozoan Amathia convoluta [1]. In contrast to the
pharmacologically inactive nonglycosylated indigo, the akashines exhibit a considerable growth
inhibitory activity toward various human tumor cell lines [2,3].
Our approaches to glucopyranoside-incorporated 4,6-dibromoindoline-2,3-dione 4 from
monosaccharide 1 presented below shows benefit from the rapid advances in mainstream
carbohydrate chemistry, allowing for convenient integration in glycosylated Convolutamydine
A-E preparation.

The versatile, simple, and often cost-effective protocols in accessing monosaccharide
derivatives and 3,5-dibromoaniline 2 and its analogues, as well as future improvements thereof,
provide suitable building blocks 3, 4 for the assembly of sugars and other natural products
derivatives like 5 for growth inhibitory activity toward various human tumor cell lines.
The author gratefully acknowledges the bilateral project (13.820.19.07 STCU.A/5800) for
financial support and Prof. Macaev F. for helpful discussions.
References:
1. Kamano Y., Zhang H.P., Ichihara Y., Kizu H., Komiyama K., Pettit G. R. Tetrahedron
Lett. 1995, 36, 2783.
2. R. P. Maskey, I. Grun-Wollny, H. H. Fiebig, H. Laatsch. Angew. Chem., Int. Ed. 2002,
41, 597.
3. R. P. Maskey, I. Grun-Wollny, H. H. Fiebig, H. Laatsch, Angew. Chem. 2002, 114, 623.