Diphenyl Sulfide Derivatives

4 -tetrahydroxydiphenylsulfldewith triflnoroacetic anhydride in the presence of aluminium chloride in ethylene dichloride atr.t. (10%) [4689]. 

20 Aromatic Ketones Containing Only Acetyl Groups 

2-hydroxy-acetophenone in the presence of copper powder in chloroform at 60° for 10 min [5924]. 

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The smooth intramolecular nucleophilic displacement of biphenyl carboxylic acids leading to benzocoumarins (See Section II.A.) inspired also investigation of the behavior of similar diphenyl ether, diphenyl sulfide and A-methyldiphenyl amine derivatives 458 under similar conditions. However, all these attempts to achieve cyclization to tricyclic compounds 459 were unsuccessful, probably due to the unfavorable stereochemistry for the formation of the required seven-mem-bered transition states and also to the presence of the deactivating bridge groups X (Eq. 42) [68JCS(C)1030]. 

A comparative study of the (3-menthyl (Men) ester of aspartic acid with other cycloalkyl esters showed that this ester is less susceptible to base-catalyzed aspartimide formation than the cPe, Cy, cHp, or cOc derivatives. Boc-Asp(OMen)-OH is prepared by esterification of Boc-Asp-OBzl with menth-l-ol by the DCC/DMAP procedure (see Section 2.2.2.5), followed by hydrogenolysis. The menthyl ester is stable to TFA treatment and is cleaved by HF or 1M TfOH/thioanisole in TFA within 60 min in an ice bath. For some syntheses, dependent on the peptide sequence, an excess (1.4 equiv) of Boc-Asp(OMen)-OSu has to be used, presumably owing to the bulkiness of the protected side chain. For the cleavage of the Men group, in some cases diphenyl sulfide (20 equiv) has to be added as a scavenger to the 1M TfOH/thioanisole/TFA mixture to facilitate its removal. However, acid-catalyzed aspartimide formation cannot be fully prevented. 

Thiophene is generally considered the most aromatic of the five-membered heterocycles, hence its reluctance to function as a diene in cycloadditions. A detailed study of the reaction of thiophene with six common benzyne precursors showed that side reactions with intermediates en route to benzyne often dominate the reaction course. Best results were obtained with diphenyliodonium-2-carboxylate 294, which gave up to 30% yields of naphthalene, presumably mainly through intermediate 295. Other benzyne-derived products [benzo( )thiophene, 0.5% 2-phenylthiophene, trace diphenyl sulfide, trace 1- and 2-naphthyl phenyl sulfides, 9 and 6%, respectively o-(2-thienyl)biphenyl, 4%] bring the... 

A first retrosynthetic approach disconnects the C-N bond yielding a diphenyl sulfide that can remake the initial phenothiazine via cyclization (Scheme 2). Sulfides that could produce phenothiazines by cyclization can be prepared as described in Section II.B. This is a relatively general pathway that allows for the synthesis of a large number of phenothiazine derivatives. 

In the same way, 2-bromo-2 -hydrazino-diphenyl sulfide cyclizes to AT-amino-phenothiazine (also through a benzyne intermediate) (78JHC1137). Other syntheses of phenothiazine derivatives by an Ullmann-type cyclization were reported earlier (50JA888, 81JHC759, 57USP2769002). 

SER effects have been observed for a number of adsorbates on copper hydro-sols. Triphenylphosphine, diphenyl sulfide, and benzotriazole all partially displace adsorbed pyridine from colloidal copper and result in SER spectra which contain both pyridine bands and those of the coadsorbate. Diphenyl sulfide and thio-phenol were found to displace pyridine. [207] A similar displacement of pyridine by thiophenol was observed with copper organosols. [218] Tliese results exemplify the potential of this technique for investigating the surface coordination chemistry of colloidal metals. SER spectra of cytosine and of guanine and their derivatives on copper and on silver have been reported. [219, 220]... 

Attempts to combine the activity of the naphthylazo-sulfonamides with that of the sulfones resulted in N l N"- sulfonylbis ( -phenyleneazo-l 4-naphthylene)7 bis(N > N -dialkylalkylenediamines) (II) with marked activity but which were imable to overcome DDS resistance. Of 24 diphenyl-sul-fone derivatives 5 were active and 3 were curative. Biguanide and ami-nourea derivatives of diphenyl sulfide, sulfoxide and eulfone were tested and three out of twelve were active ... 

Resonance stabilization is also forwarded as a rationale for the relatively high stability of monomeric aromatic sulfide radical cations. Extensive studies have been conducted with respect to the one-electron oxidation of diphenyl sulfide and thioanisol [130-132]. The absorption spectra of the radical cations typically show several bands based on transitions within the aromatic 7i-system but also involving the non-bonding electrons at sulfur (i ax 360 nm and 740 nm for (C5H5)2S, and 310 nm, 530 nm and possibly 740 nm for QHs-S -CH ). In their elaborate study on a variety of thioanisol derivatives, lolele cf a/. [ 131 ] provided information on extinction coefficients, being typically on the order of 1 x lO and 6 X 10 M" cm" for the UV and visible band, respectively. Oxidations of the parent sulfides by OH and several one-electron oxidants (TF, SO/", Br2 ", etc.) occur with rate constants on the order of some 10 M s . Dimerization to the corresponding (>S S<) could not be achieved in most cases, most likely due to solubility limitations. 

The chemistry of sulfonyl hydrazides and azides has been discussed and both derivatives are used as blowing and cross-linking agents in the manufacture of foam rubbers and plastics. Some of the best hydrazides for this purpose are diphenyl ether-4,4 -disulfonyl hydrazide 59 together with the corresponding thio analogue 60. These hydrazides are respectively prepared by reaction of diphenyl ether or diphenyl sulfide with excess chlorosulfonic acid as previously described (Chapter 4, p 74, 76), followed by condensation of the appropriate disulfonyl chloride with excess hydrazine hydrate. ... 

Dialkyl derivatives of aniline, diphenylamine, and carbazole, when melted with benzotrichloride and fused zinc chloride, yield triphenylmethane dyes of the malachite green type. Phenols, diphenyl sulfide, and indole react as well, but the dyes obtained are red. This test can be completed by identifying the triphenylmethane dye formed by paper chromatography (22) to differentiate, for example, dimethyl- and diethylaniline. A similar reaction results from melting the sample with oxalic acid. This reaction leads to the formation of blue dyes, characteristic of the derivatives of diphenylamine and carbazole (23). 

The C—S bond lengths vary upon changing carbon valence states. However, the sulfones and sulfoxides show less sensitivity to these changes than the analogous sulfides . These effects can be illustrated by considering the C—S bond lengths (A) in analogous dimethyl and diphenyl derivatives ... 

In contrast to a-hydroxyalkylphosphine, the derivatives of a-hydroxyal-kylphosphines (oxides, sulfides, selenides) are borylated only under severe conditions or do not react at all. Thus diphenylboric acid esters do not react with a-hydroxyalkylphosphine oxides even on prolonged heating. 2,5-Diphenyl-5-oxo-l, 3,2,5-dioxaboraphosphorinanes (107) were obtained... 

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