Quinoline-8-thiol is used as a reactant in the preparation of classical and nonclassical 6-arylthio-2,4-diamino-5-ethylpyrrolo[2,3-d]pyrimidines as antifolates and as antitumor agents.
It is more convenient to make 8-mercaptoquinoline by reduction of the disulfide. [Nakamura & Sekido Talanta 17 515 1970.] The hydrochloride (see thiooxine hydrochloride below) is more stable. [Beilstein 21 III/IV 1197, 21/3 V 30.]
