Synthesis and Reactions of a New Cyclobutanethione Derivative

Abstract

The 3,3-dichloro-2,2,4,4-tetramethylcyclobutanethione (4b) was prepared from the parent diketone by successive reaction with PCl5 and Lawesson reagent in pyridine. This new thioketone 4b was transformed into 1-chlorocyclobutanesulfanyl chloride 5 and chloro 1-chlorocyclobutyl disulfide 9 by treatment with PCl5 and SCl2, respectively, in chlorinated solvents (Schemes 1 and 2). These products reacted with S-and P-nucleophiles by substitution of Cl− at the S-atom; e.g., the reaction with 4b yielded the diand trisulfides 6b and 11, respectively. Surprisingly, only pentasulfide 12 was formed in the reaction of 9 with thiobenzophenone (Scheme 3). In contrast to 5 and 9, the corresponding chloro 1-chlorocyclobutyl trisulfide 13 could not be detected, but reacted immediately with the starting thioketone 4b to give the tetrasulfide 14 (Scheme 4). Oxidation of 4b with 3-chloroperbenzoic acid (mCPBA) yielded the corresponding thione oxides (= sulfine) 15, which underwent 1,3-dipolar cycloadditions with thioketones 3a and 4b (Scheme 5). Furthermore, 4b was shown to be a good dipolarophile in reactions with thiocarbonylium methanides (Scheme 6) and iminium ylides (= azomethine ylides; Scheme 7). In the case of phenyl azide, the reaction with 4b gave the symmetrical trithiolane 25 (Scheme 8). and 2). These products reacted with S-and P-nucleophiles by substitution of Cl -at the sulfanyl group; e.g. the reaction with 4b yielded the di-and trisulfane derivatives 6b and 11, respectively. Surprisingly, only pentasulfane 12 was formed in the reaction of 9 with thiobenzophenone (Scheme 3). In contrast to 5 and 9, the corresponding α-chloro trisulfanylchloride 13 could not be detected, but reacted immediately with the starting thioketone 4b togive the tetrasulfane 14 (Scheme 4). Oxidation of 4b with mCPBA yielded the corresponding sulfine 15, which underwent 1,3-dipolar cycloadditions with thioketones 3a and 4b (Scheme 5). Furthermore, 4b has been shown to be a good dipolarophile in reactions with thiocarbonyl methanides and azomethine ylides (Schemes 6 and 7). In the case of phenyl azide, the reaction with 4b gave the symmetrical trithiolane 25 (Scheme 8).

Formation of Phosphonylated Thiiranes in the Reaction of a Diazomethanephosphonate and Cycloaliphatic Thioketones.

“…Ethyl diazomethanephosphonate (1) was prepared by the Seyferth method. 21 2,2,4,4-Tetramethyl-3-thioxocyclobutanone (6a), 22 2,2,4,4-tetramethylcyclobutane-1,3-dithione (6b), 22 3,3-dichloro-2,2,4,4-tetramethylcyclobutanethione (6c), 11 2-adamantanethione (6e), 23 1,1,3,3-tetramethylindan-2-thione (6d), 24 2,2,6,6-tetramethylcyclohexanethione (6g), 25 thiofenchone (6f), 26 and thiocamphor (6h) 26 were synthesized by thionation of corresponding ketones following the literature procedure.…”

Reactions of (1,3,3-Trichloro-2,2,4,4-tetramethylcyclobutyl)sulfenyl Chloride with Some S- and O-Nucleophiles

“…The product was purified by repeated crystallisation from diethyl ether. ,3,3-trichloro-2,2,4,4-tetramethylcyclobutyl)disulfide (9) …”

“…8 In a recent paper, the preparation of a new stable cycloaliphatic thioketone, 2c, was described. 9 Thioketones 2a,b easily add Cl 2 to yield stable α-chlorosulfenyl chlorides 3a,b. 10 Similarly, treatment of thioketone 2c with PCl 5 in CCl 4 , gave the sulfenyl chloride 3c.…”

“…10 Similarly, treatment of thioketone 2c with PCl 5 in CCl 4 , gave the sulfenyl chloride 3c. 9 In the same paper, some reactions of 3c with non-enolizable thioketones and selected nucleophiles such as diethyl phosphite and thioacetic acid were described. The present report is focused on the results obtained in reactions of 3c with benzylsulfane (4), enolizable thiocamphor (5), and allyl as well as propargyl alcohol.…”

“…The second product was identified as the known thiocarbonyl S-oxide (sulfine) 14. 9 Both products were isolated as pure substances after chromatographic separation (TLC, ratio ca. 2:1).…”