Thiolane , structure

Other results make it clear that solvent can have a striking influence on the nature of the product. The use of aqueous alcoholic solvents rich in alcohol such as 70 - 95% aqueous alcohols, resulted in good conversion of several chalcones to thiolanes typified by the structure 7. However, the use of the solvent 80% water - 20% ethanol resulted in the formation of both thiolane structural types 7 and 32 (Figure 2) although the conversion of... 

IR spectra of thiolane oxides in the solid phase were shown to be most outstandingly different in the sulfoxide region depending on the particular crystalline state/structure a fact which can be used to advantage for conformational analysis. Also, as one could expect, the sulfoxide absorptions indicate strong hydrogen bonding. 

Two thiolane steroids, for which the structures are also presented in Figure 3 (13), were only found in a late Pleistocene mud from the Gulf of California (481, E8473). This sample contains the largest variety of OSC of all samples investigated. 

To determine the three-dimensional structure of iV-phenylthiolano[3,4-rf]thiazolidine-2-thione 5,5-dioxide (13), an X-ray diffraction study was carried out. The thiazolidine ring is planar, while the thiolane ring has an envelope configuration, presumably the result of the effect of the thiazolidine ring portion (82CHE668). 

C22H26N2O6S3, Mr 510.64 needles ( )4 ethyl acetate) mp. 155 C (decomp.), [ajp +140° (CH3OH). A structurally unusual streptomycete antibiotic with a 1,2-di-thiolane-3-one 1-oxide unit linked in a spirane-like manner to an 18-membered, highly unsaturated lactam ring. L. exhibits strong activity against various experimental tumors. Two possible mechanisms of thiol-ac-... 

Generally, low solubility favors adsorption. The dramatic effects of the solute-solvent interaction on adsorption may be illusffated by adsorption of aqueous solutions of thiolane and its derivative, sulfolane. Sulfolane is of interest because it has been used for more than 40 years for solvent extraction in a number of industrial processes (e.g., the Sulfinol process for CO2 removal, the UOP Sulfolane process for recovery of aromatics from hydrocarbons, processes for extraction of fatty acids, etc.). It has now become a serious pollutant for ground water, however. The structures of sulfolane and thiolane are shown in Figure 5.10. The adsorption isotherms of their aqueous solutions on a clay sorbent are given in Figure 5.11 (Kim et al 1999). The clay had a cation exchange capacity of 0.3 meq/g, and its surface was relatively polar (more polar than carbon but less polar than silica gel and activated alumina). 

Cycloaddition reactions are particularly valuable for the construction of sulphur heterocycles, and have been intensively investigated. Thus, Diels-Alder reactions of the thiolan (22), which has an exocyclic cis-diene structure, and which is easily prepared from 2,3-bis(bromomethyl)buta-1,3-diene, have been studied. Addition of SOj gave the cyclo-adduct (23). A series of dithiabicycloheptan-3-ones have been prepared by [3 -i- 2]cycloadditions of the cyclic thiocarbonyl ylide (24) to a variety of dipolarophiles e.g., to formaldehyde to give (25). ... 

The structures of several natural products containing a thiolan ring have been determined. Among these are breynolide (30), which is a degradation product of a bio-active sulphur-containing glycoside, and several related alkaloids, e.g. thiobinupharidine (31), isolated from Nuphar plant material. ... 

Cyclic Disulphides.— Most of the syntheses of these types of compounds involved oxidation of the open-chain dithiols. Asparagusic acid, or 1,2-di-thiolan-4-carboxylic acid, a new plant-growth inhibitor, has been isolated from extracts of etiolated asparagus and its structure confirmed by synthesis. Brugeriol and isobrugeriol, trans- and cis-4-hydroxy-l,2-dithiolan... 

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