This compound can be obtained in two different ways: 1) The acylation of 5-amino-1-beta-D-ribofuranosylimidazole-4-carboxamide (I) with propionic anhydride (A) in pyridine gives the corresponding tri-O-propionyl derivative (II), which by treatment with POCl3 and triethylamine in CHCl3 is converted into 5-amino-4-cyano-1-(2,3,5-tri-O-propionyl-beta-D-ribofuranosyl)imidazole (III). The hydrolysis of (III) with methanolic ammonia yields 5-amino-4-cyano-1-beta-D-ribofuranosylimidazole (IV), which is finally cyclized with phenylcyanamide (V) in methanolic ammonia at 180 C in a pressure vessel. This cyclization can also be performed with (III) and (V) directly, using the same procedure. 2) By reaction of 2-bromoadenosine (VI) with aniline (VII) in 2-methoxyethanol at 120 C.
The reaction of guanosine-2',3',5'-triacetate (I) with amyl nitrite and bromoform at 90 C gives 2-bromoinosine-2',3',5'-triacetate (II), which is condensed with aniline (III) in refluxing methanol to afford N-phenylguanosine-2',3',5'-triacetate (IV). The reaction of (IV) with POCl3 and N,N-dimethylaniline in refluxing acetonitrile gives 6-chloro-N-phenyl-9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-9H-purine-2-amine (V), which is finally treated with ammonia in methanol to give CV-1808.