1,7-dithioxo systems. Reaction of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione with 2-aminoethanol and ethane-1,2-diamine

Abstract

The reaction of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione with 2-aminoethanol involves cleavage of the sulfide bond with formation of 3-[(2-hydroxyethyl)-amino]-5,5-dimethylcyclohex-2-ene-1-thione as the major product. The reaction of the same sulfide with ethane-1,2-diamine gave previously unknown 3-({2-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)amino]ethyl}-amino)-5,5-dimethylcyclohex-2-ene-1-thione.In continuation of our studies on the chemical properties of compounds containing an S=CC=CSC=CC=S fragment [1,2], in the present work we examined reactions of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione (I) with N,O-and N,N-binucleophiles. The reactions of dithioxo sulfide I with 2-aminoethanol and ethane-1,2-diamine were carried out in acetonitrile in an inert atmosphere. Like aminolysis of compound I reported previously [2], these reactions involved cleavage of the sulfide bond in the substrate.The reaction of I with 2-aminoethanol resulted in the formation of 3-[(2-hydroxyethyl)amino]-5,5-dimethylcyclohex-2-ene-1-thione (II) as the major product (Scheme 1). Enamino thioketone II was synthesized previously by reaction of 2-aminoethanol with 3-methoxy-5,5-dimethylcyclohex-2-ene-1-thione [3]. In the present article we report for the first time detailed spectral parameters of compound II. Its 1 H NMR spectrum contained signals at δ 6.49 ppm typical of =CH protons and NH signal at δ 8.08 ppm; protons of the methylene groups in the CH 2 CH 2 OH fragment resonated at δ 3.39 and 4.74 ppm, respectively, and broadened signal at δ 4.84 ppm was assigned to the hydroxy proton. In the 13 C NMR spectrum of II, the CH 2 OH signal was located at δ C 58.62 ppm, and the =C-N carbon atom gave a signal at δ C 161.48 ppm.Analysis of the 1 H ans 13 C NMR spectra showed that the reaction of dithioxo sulfide (I) with 2-aminoethanol at 20°C, apart from enamino thioketone II, produced a small amount of 3-[(2-{2-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)amino]ethoxy}ethyl)amino]-5,5-dimethylcyclohex-2-ene-1-thione (III).