Benzene thiol

The reactions of dinuclear thioaldehyde and -ketone complexes with PR3 take a different course. When the dimeric complexes 112 are treated with PMe3 a Ti-S bond in 112 is cleaved and the monomeric complexes 113 are reversibly formed (see Scheme 26), 69 The reaction of 112 with benzene-thiol led to a Ti-C cleavage and formation of 1,3-propanedithiolato-(phenylthiolato) complex.69 The reaction of binuclear p-191 rf-thioketone molybdenum complexes related to 115 (M = Mo, E = S, R = Aryl) with P(OEt)3 also gave mononuclear complexes [Mo(CO)2(Et) i72-S = C(Aryl)2 (i75-C5H5)] by a rather complicated reaction sequence. When other phosphites were employed additionally binuclear complexes derived from addition of the phosphite to one molybdenum atom were isolated.225... 

In contrast, because of similar electronegativities, the transition state for hydrogen transfer from benzene thiol to a perfluoro-n-alkyl radical should have little polar character. In confirming the important role of polar effects in these hydrogen transfer processes, a good Hammett correlation was observed for the reduction of n- c7f15i by a series of arene thiols [141,143]. 

Thiol 33 was made by the thiourea method from 35 and further disconnection by the methods from previous chapters takes us back to available benzene thiol 39. 

The first sulfide needs only a weak base as benzene thiol is acidic and the electron-donating BuS group directs para. The rest is straightforward.4... 

It is interesting that with the rather mild catalyst pyridine hydrochloride, benzene-thiol does not react with saturated ketones, but reacts with a,p-unsaturated ketones to give thioenol ethers (with increased conjugation) or 1,4-additions.35... 

Remarkably, thermolysis of the Baylis-Hillman adducts 311 (R1 = alkyl or aryl Rz = Ac, CN, CC Me) in toluene at 210 °C in a sealed tube gave stereoselectively the cyclized product (+)-312, which included incorporation of the elements of the solvent and, when Rz = Ac, a single isomer was obtained (Equation 33). The yields were moderate (37-56%) and when RZ = CN and C02Me some racemization occurred. Similar results were obtained when either p-xylene or mesitylene was used but no reaction occurred when chlorobenzene or anisole was used. Unsaturated rings are obtained in similar yields and stereoselectivity if the N-substituent is an alkyne. In addition, benzene thiol reacted in boiling benzene in the presence of AIBN to give 313, which on ozonolysis yielded the cyclic ketones 314 ( = 1-3) in 52-70% yield <2001JOC1612>. 

Thiophenol, also known as benzene thiol, is a small molecule that does not exhibit the pre-resonance issues of dye molecules. Thiophenol has been shown to produce relatively stable monolayers on silver and gold surfaces which make it a convenient reference compound for SERS substrates [28, 29, 38, 39]. When the SERS substrate is immersed in an ethanolic solution of thiophenol, the sulfur groups form covalent bonds with the metal surface, forming self-assembled mono-layers over time, as illustrated in Fig. 4.1. 

Fig.11.2 Optical spectra of various optical probes, (a) Photo-luminescence spectra of Q-dots (from the work by Michalet et al. [2]), (b) scattering spectra of gold nanoparticles with different aspect ratio (from the work by Jain et al. [3]), and (c) fluorescence spectrum of FITC (black line) and SERS spectrum (red line) of benzene thiol with 514.5 nm photo-excitation (from the work by Jun et al. [4]). Raman band has much narrower bandwidth than the others...

In principle, cyclic systems with six units cannot be formed directly in this reaction, however, in a related reaction in which the oxidized form of 8. that is 4,4 -sufonylbis(benzene thiol) is reacted with 4,4 -dichlorodiphenylsulfone, the cyclic system containing six aromatic rings has been found to predominate. This arises by intramolecular displacement of a bridging thioether group rather than a terminal halide. 

Thiol (12) is made by the thiourea method from halide (14), and this is clearly derived from the Friedel-Crafts product (15). Benzene thiol is available. 

In general, aldehydes react more readily than ketones of thiols, a-toluenethiol condenses more easily than ethane-, pentane-, or benzene-thiol.418... 

In addition, several Tc(V) complexes based on the 0=Tc(S)4-core have been prepared. The preparation w as achieved by exchange reaction of Tc(V) gluconate with various dithiols in aqueous cthanolic solution. The oxo-dithiolatotechnetatc(V) complexes were mostly precipitated as the Et4N] salts. The complex compounds turned out to be diamagnetic in solution, and have probably square pyramidal structure [117,118,119]. Stereoisomcric complexes derived from mesa and racemic 2.3-dimer-captosuccinic acid dimethylcster were identified by H NMR [120]. The kinetics of the reaction between pcrtcchnetatc and meso- or racemic dimcrcaptosuccinic acid in hydrochloric acid solution were studied. The reaction was found to be first order in each reactant [121]. Also the reaction of pertechnetate with para-substituted benzene thiols was followed and showed a simple second order kinetics. The reaction rate decreased when the substituent became more electron-withdrawing [122]. 

Electrophilic aromatic substitution is not observed with benzenethiol either. Instead, the treatment of two equivalents of benzene thiol with the S-dication, as shown in Equation (15), gives the oxidation product, diphenyl disulfide, and the monocyclic bis-sulfide as the reduced 5-dication. The disulfide dication (36) similarly oxidizes 1,2-diphenylhydrazine into azobenzene without any accompanying substitution products <93T1605>. 

There are no electrophilic aromatic substitution reactions, analogous to those of S-dications or Se-dications, reported in the literature involving the Te-dication (58). As expected, the oxidant properties of the Te-dication are observed in reactions with 1,2-diphenylhydrazine and with benzene thiol where oxidation products, azobenzene and diphenyl disulfide, are obtained respectively. Unlike its S-dication counterpart, the Te-dication does not undergo hydrolysis with water and retains its oxidant properties. NaBH4 reduction converts the Te-dication (58) into the cyclic bis-telluride (59) <91TU537>. 

Scavengers are usually added to arrest the p-methoxybenzyl carbocation before it can do any collateral damage. Typical combinations of Lewis acid and scavenger are trifluoroborane and triethylsilane tin(IV) chloride and benzene-thiol - catalytic amounts of tin(II) chloride dihydrate and ethanelhiol - catalytic amounts of trichloroalane and ethanethiol magnesium bromide etherate and dimethyl sulfide and trichloroborane and dimethyl sulfide [Scheme 4.188]. Cerium(III) chloride heptahydrate together with sodium iodide cleaves p-methoxybenzyl ethers in refluxing acetonitrile- as does iodine in refluxing methanol but in the latter case, isopropylidene acetals do not survive. ... 

In an acid dilute alcohol medium, comparable to wine (pH 3.2), de Freitas (1995) showed that the carbocation formed from procyanidin B3 (Figure 6.23) could easily react with a nucleophilic compound, such as ethanethiol. The 4-o -ethylthioflavan-3-ol derived from (-l-)-catechin has been isolated and synthesized (Figure 6.24). Its structure has been formally established by NMR of the proton and Ci3 after acetylation. Thiolysis is a standard technique using various thiols (toluene a-thiol, benzene thiol) to study procyanidic oligomer structures. This... 

In connection with a study of a number of anticancer compounds which, presumably also act as inhibitors of free-radical polymerization, eight classes of compounds were studied as to their inhibitory properties. The classes studied were unsaturated hydrocarbons, phenolic compounds, quinones, amines, stable free-radicals, sulfiir compounds, carbonyl compounds, and metallic salts. The most effective inhibitors, of those evaluated, were cupric acetate and cupric resinate, followed by /runs-1,3,5-hexatriene, hydroquinone, benzoquinone, and diphenylamine as modest inhibitors. Among the low-activity inhibitors were 2,2-diphenyl-1-picrylhydrazyl, benzene thiol, and crotonaldehyde [70]. 

The charge-transfer complexes formed by iodine with ethane- and benzene-thiols, diphenyl sulphide, and diphenyl disulphide have been investigated in cyclohexane at 25 °C. Spectroscopic data for the 1 1 complexes and the... 

Ehrenson, Brownlee, and Taft have reported that their a/t values do not give results with phenol which are comparable to the results obtained with other systems. We have examined a number of set of substituted phenol ionization constants in water and other protic solvents and one set in a dipolar aprotic solvent. The results are fairly comparable with those obtained for NH " ", NMe2H", and NHZa as active groups. We would suggest that the a/ values can be applied successfully to phenolic reactivities and that the differences observed by Ehrenson, Brownlee, and Taft may be due in part to the data examined. Best results are obtained when the data have all been obtained in the same laboratory or alternatively when only those values are considered for which the error is known and is not more than 0.05 pX units. The one set of pX data for 4-substituted benzene thiols in water also gives excellent results. We conclude then, that the ionization constants of active sites of the type NHa" ", NMeCH", NHZa, CHZa, OH, and SH and probably to other... 

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