9H-Purine, 6-[(1-methyl-4-nitro-1H-imidazol-5-yl)thio]-9-.beta.-D-ribofuranosyl-, compd. with ethanol (4:1) 9H-Purine, 6-[(1-methyl-4-nitroimidazol-5-yl)thio]-9-.beta.-D-ribofuranosyl-, compd. with ethyl alcohol (4:1) NSC91745