Functionalized thioethers

This functionalized thioether dps ligand is also formed under solvothermal conditions at 120°C by in situ cleavage of both S-S and S—C(sp2) bonds of starting material 4,4 -dithiopyridin.126 In the presence of Cul in a 1 2 ratio using MeCN as the reaction medium, polymeric [ Cu4(p,3-I)4 (dps)2] (6) was isolated in 85% yield according Scheme 4. 

The complexation of Cu(II) by water-soluble hydroxy-functionalized thioether macrocycles has also been reported (163). 

Uses Reactive functional thioether additive for electroplating baths... 

Facile preparation of size-controlled GNPs using versatile and end-functionalized thioether polymer ligands... 

Huang X, Li B, Zhang H, Hussain I, Liang L, Tan B (2011) Facile preparation of size-controlled gold nanoparticles using versatile and end-functionalized thioether polymer... 

Sulfur Substituents. Acetylation and alkylation of pyridinethiones usually take place on sulfur (39). An exception to this is 4-pyridinethione [19829-29-9] which is acetylated on nitrogen. Displacement of thioethers can be achieved with hydroxide or amines (eq. 13) (40). Thioether functional groups can also be removed by reduction (39). 

A wide variety of /3-lactams are available by these routes because of the range of substituents possible in either the ketene or its equivalent substituted acetic acid derivative. Considerable diversity in imine structure is also possible. In addition to simple Schiff bases, imino esters and thioethers, amidines, cyclic imines and conjugated imines such as cinnamy-lidineaniline have found wide application in the synthesis of functionalized /3-lactams. A-Acylhydrazones can be used, but phenylhydrazones and O-alkyloximes do not give /3-lactams. These /3-lactam forming reactions give both cis and /raMS-azetidin-2-ones some control over stereochemistry can, however, be exercised by choice of reactants and conditions. 

Cytochromes c (Cyt c) can be defined as electron- transfer proteins having one or several haem c groups, bound to the protein by one or, more commonly two, thioether bonds. Cyt c possesses a wide range of properties and function in a large number of different redox processes. 

Silyl-derived protective groups are also used to mask the thiol function. A complete compilation is not given here since silyl derivatives are described in the section on alcohol protection. The formation and cleavage of silyl thioethers proceed analogously to simple alcohols. The Si—S bond is weaker than the Si—O bond, and therefore sulfur derivatives are more susceptible to hydrolysis. For the most part silyl ethers are rarely used to protect the thiol function because of their instability. Silyl ethers have been used for in situ protection of the — SH group during amide formation. ... 

A great advantage of catalyst 24b compared with other chiral Lewis acids is that it tolerates the presence of ester, amine, and thioether functionalities. Dienes substituted at the 1-position by alkyl, aryl, oxygen, nitrogen, or sulfur all participate effectively in the present asymmetric Diels-Alder reaction, giving adducts in over 90% ee. The reaction of l-acetoxy-3-methylbutadiene and acryloyloxazolidinone catalyzed by copper reagent 24b, affords the cycloadduct in 98% ee. The first total synthesis of ewt-J -tetrahydrocannabinol was achieved using the functionalized cycloadduct obtained [23, 33e] (Scheme 1.39). 

Much of the current work is based on the fact that the side chain can be replaced by an alternative functionality, which contains sulfur. Metabolic destruction presumably involves the readily oxidized thioether groups. 

Surprisingly there are relatively few data on the cathodic or anodic behaviour of sulfoxides 77. It is quite interesting to consider that the sulphoxide function is intermediate between the corresponding thioether and sulphone. Thus data concerning the cathodic properties of sulphoxides derive both from the basicity of the S=0 group and from their capability to allow the formation of the corresponding thioether, while cleavage reactions on the C—S bond are quite unusual. On the other hand, oxidation may provide sulphones. 

This method for introduction of the thioether functional group tolerates the presence of a broad range of functional groups, such as alkene, ester, carbonyl, and cyano groups. 

Konig et al. have achieved thioether functionalization of T8[CH = CH2]8 via the radical addition of thiols such as thiophenol, cyclohexylthiol, and 2-mercaptopyridine in the presence of azobisisobutyronitrile (AIBN) as a radical initiator (Table 13), while Gao et al. have also used this method to prepare very highly functionalized POSS by reacting T8[CH = CH2]8 with thiol-terminated glycosides giving glycoclusters in 70% yield (Figure 22). 

The reactivity of epoxides can be modified by various proximal functionality. For example, 2,3-epoxy sulfides 118 are converted to the corresponding TMS-thiiranium species 119 upon treatment with TMS triflate. This intermediate reacts with O-silyl amides regiospecifically to form l-substituted-3-hydroxy-2-thioethers (e.g., 120). Simple primary amines undergo polyalkylation, but imines can be used as an indirect amine equivalent <96TET3609>. 

Primary phosphines (R-PHj) are an important ciass of compounds in organophosphorus chemistry. Aithough discovered over a century ago, their chemistry and appiications have gained prominence in recent years. This review discusses recent deveiopments on synthesis, moiecuiar structure, properties, and appiications of primary phosphines. In particular, discussions on synthesis and properties emphasize recent results from our laboratory on the chemical architecture of amide, thioether, and carboxylate functionalized primary bisphos-phines. The utility of bromo- and aminopropyl phosphines (X(CH2)3PH2 X=Br or NH2) as building blocks to produce designer primary phosphines that display exceptional oxidative stability is described. The review also discusses the utility of carboxylate functionalized primary phosphines for incorporation on to peptides and their potential applications in catalysis and biomedicine. 

Keywords. Primary phosphines, Thioether phosphines, Amido phosphines, Carboxylate phosphines, Functionalized phosphines... 

The thioether functionalized bisphosphonates, 7 and 8, upon reduction with LiAlH4 produced the corresponding S2P2 and S3P2 primary bisphosphine frameworks 9 and 10 respectively in good yields (Scheme 4) [47,48]. 

Scheme 4. Synthesis of thioether functionalized primary phosphines 9 and 10...

These thioether functionalized primary bisphosphines 9 and 10 showed modest oxidative stabilities and have found applications as novel precursors in the development of functionalized water-soluble phosphines via formylation reactions across P-H bonds (see below) [47]. 

Additional examples of thiol (11) [49] and thioether (12) functionalized primary phosphines are outlined in Scheme 5. 

It is striking to note that the new generation of amide, thioether and car-boxylate functionalized primary bisphosphines, 1,10,16,18, and 19 as shown in Fig. 3, provide examples of primary bisphosphines with unprecedented oxidative inertness. 

Recent studies in our laboratory have demonstrated that formylation of P-H bonds can be achieved without the aid of transition metal catalysts under mild reaction conditions [47]. For example, amide and thioether functionalized primary phosphines, 5 and 9 respectively, upon treatment with 37% formaldehyde produced the corresponding amide/thioether functionaUzed water soluble phosphines 21 and 22 respectively in near quantitative yield (Scheme 10) [47]. 

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