Sulfide derivatives

The thioboration of terminal alkynes with 9-(alkylthio)-9-borabicyclo[3.3.1]-nonanes (9-RS-9-BBN) proceeds regio- and stereoselectively by catalysis of Pd(Ph,P)4 to produce the 9-[(Z)-2-(alkylthio)-l-alkeny)]-9-BBN derivative 667 in high yields. The protonation of the product 667 with MeOH affords the Markownikov adduct 668 of thiol to 1-alkyne. One-pot synthesis of alkenyl sulfide derivatives 669 via the Pd-catalyzed thioboration-cross-coupling sequence is also possible. Another preparative method for alkenyl sulfides is the Pd-catalyzed cross-coupling of 9-alkyl-9-BBN with l-bromo-l-phe-nylthioethene or 2-bromo-l-phenylthio-l-alkene[534]. 

Chloro- and 2-acetamido-5-sulfide derivatives are readily oxidized to the corresponding sulfones, while curiously enough 2-hydroxy-5-arylsulfides are reported to be stable to oxidation (228, 55 )-... 

The Gassman indole synthesis involves an one-pot process in which hypohalite, a P-carbonyl sulfide derivative 2, and a base are added sequentially to an aniline or a substituted aniline 1 to provide 3-thioalkoxyindoles 3. Raney nickel-mediated desulfurization of 3 then produces the parent indole... 

The carbenoid displacement reaction (see Section 1.4.5.2.1.4.) of the optically active acetoxy sulfide derivative 19 (or the corresponding methoxymethyl ether) with diazomalonate in the presence of a catalytic amount of rhodium acetate in refluxing benzene affords the tram-alkylation productl22. 

Scheme 1.59 Test reaction with diamino sulfides derived from ephedrine.

Almost no attention has been paid to diphosphine sulfides employed as chiral ligands for palladium-catalysed nucleophilic substitution reactions. In this context, enantiomerically pure diphosphine sulfides derived from 2,2 -biphosphole, which combined axial chirality and phosphorus chiralities, were synthesised, in 2008, by Gouygou et al. through a four-step synthetic sequence. Among various palladium catalytic systems derived from this type of ligands and evaluated for the test reaction, that depicted in Scheme 1.62... 

Fresh and frozen human tissue samples obtained from brain, liver, and kidney have been analyzed for hydrogen sulfide levels by sulfide-derived methylene blue determination using ion-interaction reversed-phase HPLC (Mitchell et al. 1993). This method can quantify nmol/g levels of sulfide. Gas dialysis/ion chromatography with ECD has been utilized for measurement of sulfide in brain tissue with 95-100% recovery (Goodwin et al. 1989). 

The sulfide derivative of furocoumarin based natural products can be synthesized by treatment of a thiadiazole 107 with KO-f-Bu and an organohalide in an one-pot operation. This process presumably involves the generation of a phenolate 108 and is followed by an intramolecular proton shift and a rearrangement to give an alkynethiolate 109, which undergoes a sequence of intramolecular proton shift, cyclization and alkylation to lead to the furocoumarin product. The thiadiazole, in turn, can be prepared by reaction of the corresponding acetyl precursor with carbethoxyhydrazine, followed by treatment with thionyl chloride . 

Interaction of substituted arenediazonium salts with potassium O. O-diphenylphosphorodithioates gave a series of solid diazonium salts which decomposed explosively when heated dry [10], The unique failure of diazotised anthranilic acid solutions to produce any explosive sulfide derivatives under a variety of conditions has been investigated and discussed [6]. Preparation of diaryl sulfides from interaction of diazonium and thiophenoxide salts led to violent explosions, attributed to presence of some arenediazo sulfide during subsequent distillation of the diaryl sulfides. Precautions are detailed [11]. A safe method of preparation of diaryl sulfides from diazonium tetralluoroborates and sodium benzenethiolate in DMF is now available [12],... 

The role of sulfur in these vents is complex and often obscured by its multiple redox states and by uncertainties in the degree of equilibration. Studies by Styrt et al. (1981), Arnold and Sheppard (1981), Skirrow and Coleman (1982), Kerridge et al.(1983), Zierenberg et al. (1984), and others have shown that the sulfur in these deposits is enriched in S relative to a mantle source (typical 5 " S ranges are between 1 and 5%c), implying small additions of sulfide derived from sea water. 

However, formation of this bond through the conjugate addition of a soft sulfur nucleophile to a,P-unsaturated aldehydes is efficiently catalysed using iminium ion catalysis [116], Using diarylprolinol silyl ether 55 the addition of a series of sulfur based nucleophiles to a variety of a,P-unsaturated aldehydes was shown to be effective (73-87% yield 89-97% ee). The products were isolated as their p-hydroxy sulfide derivatives 73 after in situ reduction of the products (Scheme 33). 

For the synthesis of selenocysteine derivatives that are suitable for peptide synthesis essentially two approaches have been used to date (1) conversion of p-chloroalanine 23 or serine-O-tosylate derivatives 24 into the desired selenocysteine derivatives by a nucleophilic displacement reaction with an areneselenol and (2) full reduction of selenocystine and in situ reaction with aryl halides to produce the aryl selenides. 7 25 In this context, reduction of selenocystine in 2 M NaOH with 2-methyl-2-propanethiol for concomitant formation of the mixed selenide/sulfide derivative 5e-(tert-butylsulfanyl)selenocysteine in analogy to the formation of 5-(fett-butylsulfanyl)cysteine 26 fails as a consequence of the difficult reduction of the diselenide with monothiols. 27 ... 

Table 8. P-NMR Chemical Shift Differences0 for Diastereomeric 1,3,2-Oxazaphospholidine 2-Sulfide Derivatives of Amines40...

Synthesis conditions and analytical results (Table II) are consistent with the hypothetical structures of sulfur lignin shown in Figure 2. Sulfur lignin is an aromatic thioether and it resembles polyphenylene sulfide derivatives (8). 

Oxide- and Sulfide-derived Compounds 34.2.8.1 Oxides and peroxides... 

The synthesis of the thiophene ring system by formation of a bond between the two /3-carbons of a diethyl sulfide derivative, or between the (3 -carbon and an ortho position of a phenylthio ethyl derivative, has been one of the most widely exploited methods for the preparation of thiophene derivatives. 

An interesting cleavage of a carbon-sulfur bond in benzylic and allylic sulfides derived from 5-mercapto-l -phenyl-1 //-tetrazole has been reported [326]. The overall reaction is an alkylation a to a carbonyl group. 

Quinones, thiazoles, oxazoles Esters, carbonyl compounds, sulfide derivatives, carbinols Same as methyl acetate... 

Various l,3,2-diazaphospholidin-4-thione-2-sulfides 91 were prepared in moderate yield by the reaction of 3-substituted glycinamides 89 with Lawesson s reagent 90 in benzene at 55-60°C (Equation 6) <1999HAC105, 1997PS(129)111>. A similar procedure based on the reaction of Lawesson s reagent 90 with a-aminonitriles was used for the synthesis of 1,3,2-diazaphospholidine-4-thione 2-sulfide derivative 92 <2001S2445>. 

Many individual flavor chemicals which were isolated and identified from Maillard "side reactions" have been reported in the patent literature. It is evident from these patents that much work has been done to glean specific flavor chemicals from the complexities of the Maillard reaction. 3-Furyl alkyl sulfide, disulfide, and 0-chalcogenalkyl sulfide derivatives are claimed to provide bloody, meaty, and roasted notes to beef broth and beef products (64-66). 3-Methylcyclopent-2-en-l-one was declared for its flavor eiiEancement of beef bouillon (67). Firmenich claimed 2,6-dimethyl-2-octenal and its analogs as possessing meat flavor qualities (68). A method to produce disulfides for application to meat and savory flavors was patented (69). 

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