Thiols incorporation

Our retrosynthesis for the epipolythiodiketopiperazine alkaloids by and large observes the basic strategic framework laid out in the synthesis of (+)-11,11 dideoxyverticillin A (1) the main deviation is aptly in the final stages of thiol incorporation (Scheme 9.11). 

Quantification of the thiol-ene coupling was carried out by H-NMR and revealed, in all cases, reduction of the double-bond peak at =5.4 ppm in the spectra of the final product. This finding suggested that the efficiency of thiol-ene coupling was >75% for the reaction undertaken with the thiol with an internal ester moiety, and >95% for reactions carried out with the aliphatic thiol incorporating an internal amide moiety. Values of molecular weight after functionalisation were 16-26 kDa. 

The chemistry of organic sulfur compounds is very rich and organosulfur compounds are incorporated into many molecules. Thiols, or mercaptans as they were originally called, are essential as feedstocks in the manufacture of many types of mbber (qv) and plastics (qv). They are utilized as intermediates in agricultural chemicals, pharmaceuticals (qv), ia flavors and fragrances, and as animal feed supplements. Many reviews have been undertaken on the chemistry of the thiols, regarding both their preparation and their reactions (1 7). 

Arylidene-5-oxazolones undergo a ring-opening reaction with aromatic thiols and a second mole of thiol is then incorporated to give products such as 48. ... 

The cleavage of epoxides by water is a classical reaction. Such epoxide cleavage can be catalyzed by both acids and bases in aqueous media. In the presence of other nucleophiles, the corresponding nucleophilic ringopening products are obtained with the nucleophiles being incorporated into the products.68 Examples include azides, iodides, and thiols in the presence or absence of metal salts in aqueous media. The pH of the reaction medium controls the reactivity and regioselectivity of the... 

Develop bifunctional ligands which NCI, NIH have a high affinity for Pb(ll) and Bi(lll) systematic exploration of incorporating thiol donor groups into chelating agents... 

Linen esterified with thioglycolic acid to incorporate thiol groups, these being more strongly nucleophilic than hydroxy groups. 

Fig. 6 Schematic representation of an Hg-drop LAJ incorporating SAMs of organic molecules of (a) alkanethiols, (b) oligophenylene thiols and (c) benzylic derivatives of oligophenylene thiols of different length formed on an Ag electrode, (d) Semi-logarithmic plot of measured current at applied bias I 0.5 V vs electrode gap flowing through the a, b, c interfaces...

When thioxo (or thiol) derivatives (as part of a thiourea function incorporated into the heterocyclic system) are present, effective. Y-alkylation is observed. Thus, the 3-heteroaryl-substituted [l,2,4]triazolo[3,4-/)][l,3,4]thiadiazole-6(5//)-thiones 37 dissolved in sodium hydroxide solution react with alkyl halides to afford the corresponding 6-alkylthio derivatives 38 (Equation 4) <1992IJB167>. The mesoionic compounds 39, inner salts of anhydro-7-aryl-l-methyl-3-methylthio-6-sulfonyl-[l,2,4]triazolo[4,3-A [l,2,4]triazolium hydroxides, are methylated with methyl iodide to give the corresponding quaternary salts 40 (Equation 5) <1984TL5427, 1986T2121>. 

Further, N-methyl dithiocarbamate (MDTC) (.9) and N-metylglycine (sarcosine) (10) were similarly incorporated into PVC matrices resulting in the derivatives usable to chelate forming and introduction of thiol-function as shown in following scheme. Of the two main purpose of modification of commercial polymers 1) improvement of original property of each polymer and 2) incorporation of new function into the polymeric materials, our studies would be served from the viewpoint of the latter as the fundamental design for PVC and PECH with specific functions. 

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