LAUSR

Abstract By mixing guaiazulene-3-methanol derivatives and thiols at room temperature, benzylic substitution of the alcohol proceeded to yield the corresponding sulfide. Because of the blue color of the guaiazulene derivative, this spontaneous reaction was used for labeling of paper-immobilized biothiols. By treatment with tris(2-carboxyethyl)phosphine hydrochloride, the guaiazulene-3-ylmethyl part of the sulfide could be removed and the original thiol recovered. Based on these findings, a guaiazulene-3-methanol derivative was used as a protective group for the synthesis of cysteine derivatives.