Publications

This report describes the synthesis and antiviral effects of (6'R)-6'-C-ethynyl, -ethenyl, and -ethyl derivatives of neplanocin A (7a, 8a, and 9a, respectively) and the corresponding 6'S-diastereomers (7b, 8b, and 9b, respectively), as examples of 6'-C-substituted analogues of neplanocin A. Grignard reaction of the 6'-formyl derivative 4, which was readily prepared from neplanocin A, with ethynylmagnesium bromide gave a diastereomeric mixture of the corresponding 1,2-addition products 5a and 5b. After removal of the protecting groups, (6'R)- and (6'S)-6'-C-ethynylneplanocin A's (7a, 7b) were separated. The corresponding ethenyl derivatives 8a and 8b and ethyl derivatives 9a and 9b were prepared by catalytic hydrogenation of 7a and 7b, respectively. As compared to neplanocin A, the new neplanocin A derivatives were much weaker inhibitors of S-adenosyl-L-homocysteine hydrolase, the R-diastereomers being more inhibitory than the S-diastereomers. The decreasing order of activity was 7a > 8a > 7b > 9a > 8b > 9b. The cytotoxicity (for CEM cells) followed exactly the same order. Of these compounds, (6'R)-6'-C-ethynylneplanocin A (7a, RENPA) showed an antiviral activity spectrum that was comparable to, and an antiviral specificity that was higher than, that of neplanocin A. RENPA was particularly active against those viruses (i.e. vaccinia virus, vesicular stomatitis virus) that are known to be highly sensitive to AdoHcy hydrolase inhibitors.

In December 1995, a 70-years old male was referred to us because of rapid visual loss in the right eye, one month after a central retinal artery occlusion in the left eye. This renal transplant patient, with limited renal function, was on immunosuppressive therapy. The diagnosis of bilateral progressive outer retinal necrosis (PORN) due to varicella-zoster virus (VZV) was confirmed by polymerase chain reaction (PCR) detection of VZV DNA in the aqueous fluid. As retinitis progressed despite of intravenous acyclovir administration, the antiviral therapy was switched to oral bromovinyldeoxyuridine (BVDU). This case-report demonstrates that oral BVDU can be a good alternative to acyclovir for the treatment of VZV retinal infections.

Abstract The addition reaction of either 3-bromo-5-lithiopyridine (2a) or 3-cyano-5-lithiopyridine (2b) to 2,4:3,5-di-O-benzylidene-aldehydo-D-xylose (1) gave a D-gulo/D-ido mixture of respectively 3-bromo- and 3-cyano-5-(2,4;3,5-di-O-benzylidene-pentitol-1-yl)pyridine (3a, b). Mesylation of C-1′ followed by reaction with CF3COOH/H2O resulted in the formation of the corresponding D-xylo-furanosyl pyridine C-nucleosides. 3-Cyano-5-D-xylofuranosylpyridine (5b) was converted to 3-carbamoyl-5-D-xylofuranosylpyridine (6) with Amberlite IRA 400 (OH−). The D-xylofuranosyl C-nucleosides were evaluated for their antiviral and cytostatic activity. No significant activity was found.

Although more and more computer-aided technologies are utilised or demonstrated on well-known monuments or archaeological sites, there is - at least for the professionals working in the field - still some lack of clarity about their application. The main idea of our...