3-Chlorothietane 1,1-dioxide

B. 3-Chlorothietane 1,1-dioxide. Thietane 1,1-dioxide (14.0 g, 0.132 mol) is placed in a three-necked, 500-mL, round-bottomed flask fitted with a magnetic stirrer, reflux condenser and a chlorine bubbler, caution sinae ahtovine is poisonous, the reaation involving it should be done in a good hood.) Carbon tetrachloride (300 mL) is added to the flask (Note 4) and the suspension is irradiated by a 250-watt sunlamp positioned as close as possible to the reaction flask without touching it (Note 5) while chlorine is bubbled through the solution for 15 min at a moderate rate (Note 6). A copious white precipitate forms and irradiation and addition of chlorine must be stopped at... 

Conversion of 3-chlorothietane 1,1-dioxide to the 3-(N,N-dimethylaraino) derivative followed by reduction, quaternization, and Hofmann elimination affords a convenient route to the highly reactive thiete (thiacyclobutenel... 

C. Thiete 1,1-dioxide. A sample of 3-chlorothietane 1,1-dioxide (8.0 g, 0.057 mol) is dissolved 1n dry toluene (300 mL) (Note 7) in a 500-mL, twonecked, round-bottomed flask equipped with a reflux condenser, magnetic stirrer, heating mantle (or silicone oil bath), and thermometer. The reaction is heated to 60° C and tri ethyl amine (28.7 g, 0.28 mol, 39.5 mL) is added through the condenser. The reaction mixture is stirred for 4 hr and trlethyl-amlne hydrochloride is removed by filtration and washed with toluene (100 mL). Toluene 1s removed on a rotary evaporator and the residue 1s recrystallized from diethyl ether-ethanol (Note 8) to give a white solid (4.5-4.8 g, 75-81%) mp 49-50°C (lit3 mp 52-54 C). 

The dipole moment of thietane 1,1-dioxide in benzene solution is 4.49 The dipole moment of 3.33 D for 3-chlorothietane 1,1-dioxide is in better agreement with a planar than a nonplanar ring conformation, The dipole moments of 3-hydroxy-3-methyl-(jU = 4.73 D, dioxane, axial OH), 3,3-dimethyl (jli = 4.56D, CCI4), 3-phenoxy-( u = 4.13 D, CCU), and 2,3-dichloro-4,4-diphenyl (cis, 2a, 3e, /.i = 4.51 D, CeHg trans 2e, 3e, = 3.32 D, thietane 1,1-dioxides have been... 

The first synthesis of thiete 1,1-dioxide 248 was achieved by elimination of hydrogen chloride from 3-chlorothietane 1,1-dioxide. The overall synthesis from epichlorohydrin (chloromethyloxiran) has been improved in several details. 3-Bromothietane 1,1-dioxide ha.s been obtained by direct bromination of thietane hl-dioxide " and the 3-chloro-derivative has been obtained similarly. " ... 

A preparation of 3-substituted thiete dioxides takes advantage of the commercial availability of the parent four-membered thietanes. The latter is oxidized to the sulfone, which in turn is photochemically mono- or di-chlorinated in the 3-position. The 3-chlorothietane dioxide (239a) can be easily transformed into the thiete dioxide, whereas the 3,3-dichloro homolog is transformed into the 3-chloro-2H-thiete 1,1-dioxide (240b) (equation 91). 240b reacts with carbanions, amines, alcohols and thiols to give the corresponding 3-substituted thiete dioxides. ... 

Qy chemical transfonnation. 3-Thletanol 14-dtoxide, whidb Gontaine an hydroxyl group, can be converted to 8-chlorothietane Ll-dioxide by thionyl chloride in the presence of pyridine or, better, of 2,4,B-ooUidine. On treatment with triedi ainine in benzene at 40 c. dua derivative loses hydroohlcrio add to form thiete sulfone, whi< in turn b reduced by sodium borohydride into tiuetane 1,1-... 

Physical Properties.—Structure determinations by X-ray analysis of 2,2-dimethylthietan 1,1-dioxide and of 3-chlorothietan and 3-hydroxythietan l,l-dioxides have been accomplished. The vibrational frequencies of the sulphone group in thietan 1,1-dioxide and a number of other sulphones have been compared with hydrogen-bonding ability, calculated ir charge densities and S—O bond orders. " The signs of the proton coupling c[Pg.121]

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