Pyrazofurin B,

Pyrazofurin B (8), the a-anomer of pyrazofurin (7), was also isolated from culture filterates of the same microorganism [73BBR(51)312] and has been suggested to be produced as a result of acid-catalyzed anomerization of 7 through the intermediacy of the acyclic structure 245 (75ANY544) (Scheme 54),... 

Pyrazofurin (7) and its a-anomer pyrazofurin B (8) were obtained upon diazotization of the 3-oxo-2-(a-D-ribofuranosyl)glutarate derivative 252 followed by cyclization and ammonolysis prolonging the time of ammonolysis... 

Puromycin aminonucleoside, A-154 Puromycin hydrochloride, P-111 Puromycin, P-111 Purpurosamine A, P-20 Purpurosamine B, P-20 Purpurosamine C, D-471 Pustulan, P-112 Putidolumazine, P-113 PX Glycoprotein, P-114 4/f-Pyran, P-115 y-Pyran, P-115 1,4-Pyran, P-115 Pyrazofurin B, P-116 Pyrazofurin, P-116 Pyrazomycin B, P-116 Pyrazomycin, P-116 Pyrogallitol, C-185 Pyrrocycline C, R-155 Pyrrolosine, P-117 PZ 68, X-3... 

The synthesis of pyrazofurin A (the 4-hydroxy analogue of (17)) and its a-anomer pyrazofurin B by a Wittig condensation on a ribose derivative is mentioned in Chapter 3 (ref. 183). Further references to antibiotic C-nucleosides occur in Chapter 18. C-Nucleosides of indoles have been prepared by glycosylation using ribosyl chloride derivatives. ... 

Considering the number of naturally occurring C-glycosides known, we cannot ignore the specific class of C-nucleosides. This class of compounds is particularly important due to the antibacterial, antiviral, and antitumor properties of many of these molecules. Some examples of naturally occurring C-nucleosides are shown in Figure 1.3.6 and include pyrazofurin, showdomycin, oxazinomycin, formycin, and formycin B.17>18... 

In reversal experiments using the human B-cell line (RPMI 8422), pyrazofurin inhibited cell growth at a concentration of 10 M. This PF effect was completely reversed with the addition of 10 M to 10 M of uridine or cytidine but not by orotic acid or orotidine. This is additional confirmation of the assumption that the site of inhibition in the biosynthesis of pyrimidine nucleotides is at the site of orotidylic carboxylase ... 

It is concluded that the presence of phosphorylated pyrazofurin was established in cells incubated with pyrazofurin. Both the human T-cells and B-cells yielded essentially the same results. 

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