Oxathiazolidine derivative

Although the 1,4,2-oxathiazolidine derivatives 16 (X = O Y = S) are usually nonisolable intermediates of reactions between nitrones and thiocarbonyl compounds, in some instances a cycloaddition/cycloreversion equilibrium is established with steric hindrance influencing its position. This is the case for the kinetically stable... 

There are no reports concerning reactivity of substituents attached to ring heteroatoms. In fact, most 1,4-(oxa/thia)-2-azoles are unsubstituted at ring heteroatoms and the only data concerning dithia- or oxathiazolidine S,S-dioxides, or N-substituted derivatives is limited to their preparation and to the reactivity of the ring systems. 

A similar synthesis of enantiopure (l )-sulfinamides 123 from indane-derived toluenesulfonyl 1,2,3-oxathiazolidine-2-oxide 121 has been developed. This method includes chemoselective ring opening with inversion of configuration at the sulfur atom, using Grignard reagent at the first step and lithium amide in liquid ammonia in the second step (Scheme 17) <2002JA7880>. Intermediate stable and crystalline sulfinate esters 122 were isolated in >95% yield in diastereopure form. 

Reaction of A-sulfinyl derivative 162 with oxiranes in the presence of a catalyst such as Et4NBr and LiCl or LiBr gave the cyclocondensation products - 1,2,3-oxathiazolidines 163 (Equation 47) <1996JFC49>. 

Treatment of the oxathiazolidine (55) at 140 °C with PhNH2 or PhC02H leads to SN attack at the oxy carbon, with loss of S02 and formation of 2-substituted aminoethanes (68BCJ1925). Likewise, C-methyl derivatives, e.g. (164), are catalytically isomerized at sulfur by halide ions to an equilibrium mixture of cis and trans isomers via the intermediates (165) (75BCJ929). 

Certain oxathiazolines are useful ataraxics with low toxicity. An example is the chloroben-zylamine derivative (233) (68SAP6804299). Modest CNS depressant activity has also been found in certain 1,3,4-dioxazolines (234) (77JPS772) and in l,2,3-oxathiazolidin-5-imine S-oxides (235) (77IJC(B)133) (see also Chapter 1.06). 

Cyclic sulfamidites and cyclic sulfamidates have been prepared from l-serine. L-Serine was first converted into L-serine-O-sulfate in 40% yield, which was then converted into l,2,3-oxathiazolidine-4-carboxylate 2,2-dioxide (67BCJ1554) in poor yield. Later, Baldwin et al. (90TA881) reported an excellent overall yield of cyclic sulfamidate (52) derived from l-serine (49), as shown in Scheme 10. 

Like the reaction of organometallic reagents with cyclic sulfites, reaction of 1,2,3-oxathiazolidine 2-oxide 107 derived from ephedrine (106) and thionyl chloride with a Grignard reagent (RMgX) or an alkyllithium (QHsLi or MeLi) furnished a mixture of sulfinamides 110. 

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