A short high yielding synthesis of the potent anti-VZV carbocyclic nucleoside analogue carba-BVDU
A short high yielding synthesis of the potent anti-varicella-zoster virus (VZV) carbocyclic nucleoside analogue carba-BVDU 1 starting from aminodiol 2 is described. Reaction of 2 with acyl carbamate 3 and subsequent ring closure under acidic conditions afforded 5-ethyl-2'-deoxy-4'a-carbauridine 5. In situ acetylation of 5 afforded 3',5'-di-O-acetyl-5-ethyl-2'-deoxy-4'a-carbauridine 6 in 78% overall yield from 2. Radical bromination of 6 with either bromine or NBS and subsequent treatment with triethylamine gave an efficient conversion to 3',5'-di-O-acetyl-5-(E)-(2-bromovinyl)-2'-deoxy-4'a- carbauridine 7. Deacetylation of 7 afforded 1 in an overall 45-53% yield from 2.
Synthesis and cyanation of octaalkylporphyrins using electrochemical methods
The total synthesis of octaalkylporphyrins (ethyl, buthyl, isopropyl) and the cyanation of the meso (methine bridge) positions have been achieved using electrochemical methods.The coupled products (diketals) from anodic oxidation of aldehydes enol ethers (or enamines) in methanol, on subsequent reaction with benzyl carbamate undergo cyclisation to N-carbobenzyloxypyrroles.Deprotection and reaction with formaldehyde afforded the corresponding porphyrins.Electrolysis of zinc-octaethylporphyrin in dimethylformamide in the presence of cyanide at various concentrations and potentials (+0.45 to 0.9 V/SCE) gave mono- to tetracyano-octaethylporphyrins which were fully caracterized.
Callot, Henry J.,Louati, Abderrazak,Gross, Maurice