A detailed account is given of the syntheses of 9-alkyl-2-deuterioadenines (5b-d), adenosine-2-d (5e), and 2'-deoxyadenosine-2-d (5f) from the 9-substituted adenines 1b-f through cyclization of the aminoimidazolecarbox-amidine salts 9 or the corresponding free bases 8 with formic-d acid-d or 1-(formyl-d)-2(1H)-pyridone. Glycosidic hydrolysis of 5e with boiling 0.5N aqueous HCl afforded adenine-2-d (5a) in 77% yield. Peracid oxidation of 5a-e produced the corresponding 1-N-oxides (12a-e) in fair yields. Methylation of 9-methyl- (12b) and 9-benzyladenine-2-d 1-oxide (12d) and adenosine-2-d 1-oxide (12e) with MeI in AcNMe2 gave the corresponding 1-methoxy derivatives (13b, d, e) in good yields. Dimroth rearrangements of 13b, 13d, and 13e via the free bases 14b, 14d, and 14e furnished the N6-methoxy isomers 15b, 15d, and 15e, but their isotopic purities were unsatisfactory. Unambiguous assignments of the purine-ring proton signals in the proton nuclear magnetic resonance spectra of the unlabeled adenines (1a-f, 2a-e, 3b, d, and 10e) have been made by comparison with those of the labeled species (5a-f, 12a-e, 13b, d, and 14e).