Thioether continued

The first three-dimensional macrobicyclic TTF derivatives have been obtained <96CC615> and work on TTF-containing crown ethers and thioethers has continued <96LA551, 96JCS(P1)1995> with structures of this type being used to obtain the first TTF-containing... 

There is huge potential in the combination of biocatalysis and electrochemistry through reaction engineering as the linker. An example is a continuous electrochemical enzyme membrane reactor that showed a total turnover number of 260 000 for the enantioselective peroxidase catalyzed oxidation of a thioether into its sulfone by in situ cathodic generated hydrogen peroxide - much higher than achieved by conventional methods [52],... 

Chromium complexes (continued) organohalide activation, 5, 381 with phosphine-based supporting ligands, 5, 365 porphyrin-ligated derivatives, 5, 364 pyridinebis(imine) ligand derivatives, 5, 361 salen-ligated complexes, 5, 379 surface chemistry on oxides, 12, 525 tetradentate [04] compounds, 5, 352 tetradentate thioether derivatives, 5, 365 thiolate-bridged, Fe- and Rh complexes, 5, 308 with Ti(IV), 4, 627... 

As is the case for the complexes with pendant thioether donors, the N-alkyl complexes show a second oxidation (Epa = 0.7-0.9 V) that is coupled to the formation of a new species with an irreversible reduction (Figure 8c) the potential can be continuously cycled between +1.5 and — 1.5 V without changing the voltammogram. 

Slowly add the p-halo thioether solution from the addition funnel over a period of 18 h. Once the addition is complete, continue stirring for a further 2 h. Remove the DMF by distillation under reduced pressure (bath temperature 50°C, 0.2 mmHg) and swirl the residue with dichloromethane (2 x 150 mL) for 15 min. 

Eow-spin Fe porphyrins continue to be of major interest to many investigators, both because of the large number of different low-spin complexes that can be prepared, and because of the relevance of this spin state to a variety of heme proteins. Ligands that give rise to low-spin complexes of Fe porphyrins include two imidazoles, two imidazolates, two pyridines (for TPPs but not OEP and natural porphyrins for lower-basicity pyridines), " two thioethers, two thiolates, two isocyanides, two phosphines, two anunonia molecules, two primary amines (as amino acid esters), two cyanides, two nitrite ions, two methoxide ions, two alkyl... 

Over the years, several techniques have been developed to elucidate the structure of a new lantibiotic. The extensive post-translational modifications limit Edman degradation to a stretch of amino acids from the N-terminus to the first modification. Various chemical derivatization techniques have been used to allow continuation of the sequence and to reveal the position of the posttranslationaUy modified residues. Originally, these techniques relied on treatment with ethanethiol under highly basic conditions that result in elimination reactions of the thioethers... 

In continuation of efforts to identify Mi-selective muscarinic agonists capable of crossing the blood-brain barrier, the 3-carbo-methoxy group of arecoline was replaced by bioisosteric 1,2,5-oxadiazole (154) or by 1,2,5-thiadiazole rings with oxygen ether substituents at position 3 (155)or with thioether substituents at position 3 (156) (190). 

Synthesis and structural characterization of synthetic analogs of liver alcohol dehydrogenase (LADH) continued to be one of the most investigated fields of research. A number of ligands suitable for modeling LADH have been reported and their hydroxo zinc complexes also described.133-135 [Zn(TmMes)(HOMe)]+, for example, exhibits a coordination environment that resembles aspects of that in LADH.136 The ethanol complex [Zn(Tm Bu)(HOEt)]+ has been also isolated.137 [NS2] donor ligands, that feature thioether donors, also provide coordination environments that mimic the active site of LADH.138,139... 

The reactions of lithiophosphide reagents with alkyl halides or sulphonate esters have continued to find wide application in the synthesis of new phosphines. A series of phosphino-ethers, e.g., (22), has been prepared from the reactions of chloromethyl-substituted ethers with lithium diphenylphosphide. " A one-step synthesis of macrocyclic phosphino-ethers and -thioethers (23) is afforded by the reactions of dilithio-organophosphides with bis(j8-chloroethyl)-ethers and -thioethers derived from ethane-1,2-diol and ethane-1,2-dithiol, respectively. " A new family of water soluble phosphonio-phosphine ligands (24) has been prepared by the reaction of a,o)-dihaloalkanes with one mole of lithium diphenylphosphide, followed by quatemisation of the intermediate w-haloalkylphosphine with trimethylphosphine. The new ligand system (25) has been prepared by the reaction of chloromethylbenzene-chromium tricarbonyl with... 

TABLE XXVI. ORGANIC DERIVATIVES OF THIOETHERS (SULFIDES) a) Liquids I) Noncyclic (Listed in order of increasing b.p.) (Continued)... 

We thank Messrs. David Wliite and Simba Matondo, and Drs. Heinz-Josef Kiippers and Pliil Blower for their invaluable efforts on this project on the crown thioether chemistry, and Piofessors S.W.J. Lamberts and E.P. Krenning for their continuing counsel. 

---