Lomeguatrib192441-08-0100 % similar O6-Benzylguanine19916-73-557 % similar 6-O-Methylguanine20535-83-549 % similar Thioguanine154-42-740 % similar Guanine73-40-540 % similar Guanine hydrochloride635-39-238 % similar Guanine sulfate10333-92-335 % similar