Since the discovery of nojirimycin, a glycosidase inhibitor, polyhydroxylated piperidines (also called azasugars: the ring O‐atom of a carbohydrate is replaced by nitrogen) have attracted considerable attention and have been the target of numerous synthetic strategies during the last decade. The efficient synthesis of naturally occurring azasugars and their analogs is of considerable importance due to their potential glycosidase inhibitor properties. Some of them have been widely investigated as candidates for drugs to treat a variety of carbohydrate‐mediated diseases such as diabetes, viral infections, including HIV, cancer metastasis, hepatitis, and Gaucher’s disease. This microreview focuses on recent syntheses of azasugars. In addition, the biology of these compounds is briefly considered. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

No abstract

The nitration of 2‐(trimethylstannyl)heteroarenes by tetranitromethane (TNM) or dinitrogen tetroxide has been shown to be possible when the HOMO energy of the heteroaryltin is high enough to allow the formation of the corresponding radical cation. The reaction proceeds through a charge‐transfer complex between heteroaryltin and TNM, followed by a single‐electron transfer, which is enhanced under sunlamp irradiation. Accordingly, 2‐nitrobenzo[b]furan, 2‐nitrobenzo[b]thiophene, 2‐nitropyridine and 2‐nitroindoles were obtained by this method. However, the nitration of 2‐stannylated pyrimidine or of stannylated 1,3,5‐triazines has been shown to be impossible, due to the low energy of their HOMO orbitals. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)