A novel synthesis of noviose and its C-(4) epimer

Functional characterizations of novWUS involved in novobiocin biosynthesis from Streptomyces spheroides

NovW, novU, and novS gene products represent dTDP-4-keto-6-deoxy-D-glucose 3,5 epimarase, C-methyltransferase and dTDP-glucose-4-ketoreductase involved in noviose biosynthetic pathway, respectively. We have expressed three genes to elucidate the functions of NovW, NovU, and NovS in Escherichia coli. NovW and NovU catalyze the formation of dTDP-4-keto-6-deoxy-5-C-methyl-L-lyxo-hexose from dTDP-4-keto-6-deoxy-D-glucose. NovS reduces the product formed from the reaction of NovW with dTDP-4-keto-6-deoxy-D-glucose in the presence of NADH to result in dTDP-l-rhamnose. Furthermore, a pathway for the biosynthesis of noviose is proposed.

Synthesis of (−)-Noviose from 2,3-O-Isopropylidene-d-erythronolactol

Noviose is a key synthon for the construction of novobiocin, a clinically useful antitumor agent that has been shown to inhibit both type II topoisomerases and Hsp90. The synthesis of d-noviose from 2,3-O-isopropylidene-d-erythronolactol is described.

D-Gulonolactone as a synthon for L-noviose: first preparation of 4-O-demethyl-L-noviofuranose and related derivatives

[reaction: see text] A new synthesis of L-noviose (11), a sugar moiety of novobiocin, is presented. D-Gulonolactone was initially converted in a few steps to the key ester derivative 7 [1-O-benzyl methyl 2,3-O-(1-methylethylidene)-alpha-L-lyxofuranosiduronate]. An appropriate selection of protecting groups enabled transformation of 7 under mild reaction conditions to 4-O-demethyl-L-noviofuranose 9a and related 9b-c. Derivatives 9 were further converted either to L-lyxopyranoses (10a and 10b) or to methyl L-lyxofuranoside 12.