3- -thione atropisomers

The use of a chiral additive in the mobile phase has been exemplified by Roussel and Favrou who studied the separation of several N-aryl-thiazo-line-2-thione atropisomers on an achiral column with p or y cyclodextrin in the mobile phase. It is worth recalling that the association constants between each enantiomer and the chiral selector can be determined by varying the chiral additive concentration (93CHI471, 93JIP283). 

N-(o-Functionalized-aryl)-4-alkyl-thiazolin-2-one and thiazoline-2-thione atropisomers were nicely resolved by chiral chromatography (05LOC433). 

Figure 3. Chromatogram of atropisomers of a N-aryl-thiazoline-2-thione.

Chiral imidazoUdin-2-thione or 2-one were prepared from o-glucoseamine by reaction with o,o -disubstituted arylisothiocyanates to give 39 which can be cycHzed to 40 [76]. Thus, a variety of derivatives were prepared carrying different aryl groups and as a consequence of hindered rotation, some of them exist as stable rotamers (Fig. 7). Treatment of 39 with acetic anhydride in pyridine at low temperature gave the respective per-O-acetyl derivative imidazolidine thione, which upon elimination of acetic acid gave the imidazoline thion 41 as a mixture of atropisomers [76]. 

Bruceolline F 18, an A/ -glucosyl-indole, has been isolated from root wood of Brucea mollis Stable, separable atropisomers of the -glucosyl-pyrrole derivative 19 were obtained by elaboration of 2,3,4,6-tetra-(7-pivaloyl-p-D-glucopyranosyIamine (i, PhCMXXOEt)=M(CO)s where M=Cr or W ii, Bu NC) the isomers result from restricted rotation about the glycosidic bond." N-Gluco- and galactosyl-pyridine-2(lH)-thione derivatives such as 20 have been synthesized by... 

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