Alkyl thiol

Porter M D, Bright T B, Allara D L and Chidsey C E D 1987 Spontaneously organized molecular assemblies. 4. Structural characterization of normal-alkyl thiol monolayers on gold by optical ellipsometry, infrared-spectroscopy, and electrochemistry J. Am. Chem. Soc. 109 3559-68... 

By hydrolysis of a phthalocyaninc containing an in situ generated alkyl isothiuronium salt, alkyl thiols as side chains have been obtained.438... 

The coupling of thiols with aryl halides has been recently reported using Ni(NHC)2 complexes [171]. After screening different pre-catalysts, compound 28 showed the best behaviour in terms of activity and substrate scope, allowing the coupling of electron rich and poor aryl bromides with aryl or alkyl thiols (Scheme 6.52). 

A thio-substituted, quaternary ammonium salt can be synthesized by the Michael addition of an alkyl thiol to acrylamide in the presence of benzyl trimethyl ammonium hydroxide as a catalyst [793-795]. The reaction leads to the crystallization of the adducts in essentially quantitative yield. Reduction of the amides by lithium aluminum hydride in tetrahydrofuran solution produces the desired amines, which are converted to desired halide by reaction of the methyl iodide with the amines. The inhibitor is useful in controlling corrosion such as that caused by CO2 and H2S. 

The boron trifluoride-alkyl thiol reagent combination also operates on the basis of nucleophilic attack on an oxonium ion generated by reaction of the ether with boron trifluoride.90... 

In 1978 and 1980 the coupling of aryl bromides and iodides with both aliphatic and aromatic thiols was first reported in the presence of NaO-t-Bu and Pd(PPh3)4 (Equation (35)).118,119 In contrast to aryl halide aminations and etherifications, the thiation reactions did not require unusual catalysts. Yet, reactions that form aryl alkyl sulfides from alkyl thiols occurred in modest yields in many cases ... 

Figure 1.10 Sulfhydryl groups may undergo a number of additional reactions, including acylation and alkylation. Thiols also may participate in redox reactions, which generate reversible disulfide linkages.

Metal nanoparticles are synthesized by reduction of metal ions using reducing agents such as borohydride, amines, and 1,2-diols in the presence of stabilizing agents, typically long-chain alkyl thiols (e.g., dodecanethiol), amines,... 

Efficient addition between various nitrile oxides and both, short (C2) and long-chain (C16) alkyl thiols, aliphatic dithiols and aryl thiols occurs rapidly at... 

Sealants obtained by curing polysulfide liquid polymers with aryl bis(nitrile oxides) possess stmctural feature of thiohydroximic acid ester. These materials exhibit poor thermal stability when heated at 60°C they soften within days and liquefy in 3 weeks. Products obtained with excess nitrile oxide degrade faster than those produced with equimolar amounts of reagents. Spectroscopic studies demonstrate that, after an initial rapid addition between nitrile oxide and thiol, a second slower reaction occurs which consumes additional nitrile oxide. Thiohydroximic acid derivatives have been shown to react with nitrile oxides at ambient temperature to form 1,2,4-oxadiazole 4-oxides and alkyl thiol. In the case of a polysulfide sealant, the rupture of a C-S bond to form the thiol involves cleavage of the polymer backbone. Continuation of the process leads to degradation of the sealant. These observations have been supported by thermal analysis studies on the poly sulfide sealants and model polymers (511). 

Alkyl-substituted silicon peroxides, 78 444 Alkyl sulfates, 23 537 use in cosmetics, 7 849 Alkylsulfones, O-alkylation and, 9 280 Alkyl sulfoxide, micellization of, 24 132t Alkyl tertiary alkyl ethers, 70 575 Alkylthexylboranes, 73 639 Alkyl-thiols, 77 57 4-Alkylthiosemicarbazides, 73 575 Alkyl-tin catalysts, 20 40 Alkyltitanium halides, 25 108—109 Alkyltitaniums, 25 106 higher, 25 116... 

The base-catalysed addition of thiols to Jt-electron-deficient alkenes is an important aspect of synthetic organic chemistry. Particular use of Triton-B, in place of inorganic bases, has been made in the reaction of both aryl and alkyl thiols with 1-acyloxy-l-cyanoethene, which behaves as a formyl anion equivalent in the reaction [1], Tetra-n-butylammonium and benzyltriethylammonium fluoride also catalyse the Michael-type addition of thiols to a,P-unsaturated carbonyl compounds [2], The reaction is usually conducted under homogeneous conditions in telrahydrofuran, 1,2-dimethoxyethane, acetone, or acetonitrile, to produce the thioethers in almost quantitative yields (Table 4.22). Use has also been made of polymer-supported qua-... 

Inhibitors form a film on the surface that blocks the dissolution of the substrate. Adsorption of an alkyl-thiol to the surface of the CU3AU alloy resulted in an inaeased surface tension of the gold film this is observed as an increase in the value of <., which depresses dissolution of copper. This behavior resembles inhibition of copper corrosion on a pure copper surface where benzotriazole increases the potential to start significant copper dissolution this was demonstrated by Cruickshank et using in situ AFM. However, when the critical potential for benzotriazole film... 

Considerable research effort was focused on systems of colloidal gold of which a broad variety of synthetic procedures were reported [140 b, fj. While native colloidal gold solutions are only stable for a restricted time, Brust et al. [141] were able to overcome this problem by developing a simple method for the in situ preparation of alkyl thiol-stabihzed gold nanoparticles. This synthetic route yields air-stable and easy to handle passivated nanoparticles of moderate polydispersity, and is now commonly employed for the preparation of inorganic-organic core-shell composites. Such composites are used as catalytic systems with principally two different functions of the protective 3D-SAM layer. Either the metal nanoparticle core can be used as the catalytically active center and the thiol layer is only used to stabihze the system [142], or the 3D-SAM is used as a Hnker system to chemically attach further catalytic functions [143]. 

The cross-coupling reaction proceeds through the initial oxidation of the more reactive thiol, followed by the gradual thiolysis of the formed disulphide by the less reactive thiol. The method is therefore useful for the cross-coupling of the reactive aryl and n-alkyl thiols with the less reactive f-alkylthiols. 

This enzyme [EC 4.2.99.8], also known as cysteine synthase and O-acetylserine sulfhydrylase, catalyzes the pyr-idoxal-phosphate-dependent reaction of H2S with O -acetylserine to produce cysteine and acetate. Some alkyl thiols, cyanide, pyrazole, and some other heterocyclic compounds can also act as acceptors. 

This enzyme [EC 4.4.1.6] catalyzes the pyridoxal-phos-phate-dependent hydrolysis of an 5-alkyl-L-cysteine to generate an alkyl thiol, ammonia, and pyruvate. The reaction is an a,/3-elimination. In yeast, the enzyme may be identical to cystathionine /3-lyase. See also Alliin Lyase... 

This pyridoxal-phosphate-dependent enzyme [EC 4.4.1.10] catalyzes the reaction cysteine with sulfite to produce cysteate and H2S. The enzyme can also catalyze the reaction of two cysteines (thereby producing lanthio-nine) as well as other alkyl thiols as substrates. 

Taft and coworkers ° have reported lithium ion affinities, AGu+, for various types of compounds. Values of AGu+ for alkyl thiols, dialkyl sulfides, alcohols and dialkyl ethers (sets CP3, CP4, CPS and CP6, Table 10) were correlated with equation 27. The regression equation for the alkyl thiols is equation 58 ... 

Organized multilayers of ferrocene alkyl thiol have been self-assembled on Au(lll) under conditions of controlled thiol concentration. Several methods, such as CV, ellipsometry, STM, AFM, and in situ FTIR spectroscopy have been applied in these studies in order to find out the differences between mono- and multilayers of the same compound [152]. Similar compounds, namely, short-chain alkyl thiols (n = 3-10) with ferrocene terminal group were allowed to form organized monolayers at Au(lll) surfaces [153]. 

Fig. 5.1 Scheme for patterned deposition of PbS. (a) Self-assembled monolayer (SAM) of long-chain mercapto-carboxylic acid. On exposure to UV radiation through a mask, the exposed thiol group is oxidized to a sulphonate group (b) that is weakly bound to the An substrate and can be easily rinsed away (c). Subsequent formation of a long-chain alkyl thiol SAM occurs only on the exposed Au (d). CD of PbS occurs only on hydrophilic car-boxylate endgroups and not on hydrophobic methyl groups (e). (See Ref. 41). 

A number of volatile aliphatic compounds that contain nitrogen or sulfur atoms are important aroma constituents. Alkyl thiols, dialkyl sulfides and disulfides, and alkyl thiocyanates belong to this group. They occur widely in foods and spices and determine the odor of, for example, onions, garlic, and mustard. Because of their potent smell, they are used in high dilution and are often produced only in small quantities. The same is true for the following ... 

Sulfur is oxidatively fluorinated up to its highest valence state, six. For instance, alkyl thiols give perfluoroalkyl-sulfurpentafluorides (Fig. 40) [104] and sulfides give perfluorodialkyl-sulfurtetrafluorides (Fig. 41) [105,106]. Similarly, phosphorous is oxidatively fluorinated up to the pentavalent state (Fig. 42) [107]. 

Multifunctional ligands are able to link nanoparticles, for example in small assemblies like extended architectures. In early reports, Osifchin et al. and Brust et al. reported the self-assembly of alkyl-thiol capped gold nanoparticles using dithiol ligands [163, 164]. 

Desulfurization of Mob. The combination of FeCl2 (2 equivalents) and NaB(C2Hs)3H (4 equivalents) desulfurizes aryl, benzylic, and alkyl thiols to hydrocarbons at — 78 - 25°. CoCl2 and VCI3 are less useful metal salts. Yields are in the range 60-85% (four examples). 

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