Comparison of the reactivity of N‐(p‐toluenesulfonyl)‐sulfinimidoyl fluorides and chlorides toward triphenylphosphine

The path of the reaction of aryl‐N‐(p‐toluenesulfonyl)‐sulfinimidoyl fluorides and triphenylphosphine is highly dependent on the order of the reactants addition. Addition of triphenylphos‐phine to aryl‐N‐(p‐toluenesulfonyl)‐sulfinimidoyl fluorides results in the formation of triphenyl(aryl‐thio)phosphonium salts of N,N′‐bis(p‐toluenesul‐fonyl)aryl‐sulfinamidines and triphenyldifluorophosphorane. By changing the reagent addition order, we obtained triphenyldifluorophosphorane, P,P,P‐triphenyl‐N‐(p‐toluenesulfonyl)‐phosphine imide, and diaryl disulfides. The outcome of the reaction aryl‐N‐(arenesulfonyl)‐sulfinimidoyl chlorides and triphenylphosphine does not depend on the order of addition of the reactants. P,P,P‐Triphenyl‐N‐(arenesulfonyl)‐phosphine imides, triphenyldichloro‐phosphorane, and diaryl disulfides were formed as a result. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:66–71, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20408     

Synthesis of S‐Aryl Arenethiosulfonates from N,N‐Di(arenesulfonyl)hydrazines: Reduction of Sulfonyl Chlorides with an Organic Reagent

N,N‐Di(arenesulfonyl)‐N′,N′‐dimethyl‐hydrazines, readily prepared from arenesulfonyl chlorides and N,N‐dimethylhydrazine, were heated at 120°C in chlorobenzene to give S‐aryl arenethiosulfonates, ArSSO₂Ar, in good yields.     

Metal-Free and NBS-Mediated Direct Thiol-Disulfide Exchange Reaction to Access Unsymmetrical Disulfides

A metal-free and N-Bromosuccinimide (NBS)-mediated direct thiol-disulfide exchange reaction at room temperature is developed. A variety of unsymmetrical disulfides have been prepared with good to excellent yields. Efficient late-stage modification of amino acids and drugs demonstrates the utility of this strategy. In addition, easy to operate, broad substrate scope and good functional group tolerance further demonstrate that this reaction provides an essential complementary route to access unsymmetrical disulfides.     

N-(Morpholine-4-dithio)phthalimide: A Shelf-Stable,Bilateral Platform Molecule Enabling Access to Diverse Unsymmetrical Disulfides**

Synthetic methods for unsymmetrical disulfides are greatly needed owing to their applications in drug discovery, linker chemistry, and materials sciences. In this study, a new shelf-stable and easy-to-prepare bilateral disulfurating platform molecule, N-(morpholine-4-dithio)phthalimide, has been developed for the divergent synthesis of unsymmetrical disulfides. The amino and imide leaving groups of this reagent can be orthogonally transformed. Under acidic conditions, the amino moiety undergoes selective protonation and thus can be displaced by various carbon nucleophiles, such as allyl trimethylsilanes, alkynyl silanes, and electron-rich arenes, leaving the phthalimide moiety untouched. Meanwhile, the phthalimide leaving group is amenable to substitution under basic or neutral conditions. The combination of these transformations provides rapid access to diverse unsymmetrical disulfides through two C−S bond-forming reactions.     

N,N'-Bis(vinyloxyalkyl) Dicarboxamides

N,N'-Bis(vinyloxyalkyl)oxamides and N,N'-bis(vinyloxyalkyl)phthalamides were synthesized in 60-95% yield by reactions of vinyloxyalkylamines with diethyl oxalate and phthalimide, respectively.     

Structural and Kinetic Relations Holding in the Halogen Abstraction from Organohalogen Compounds by Alkyl Radicals

The relative rate constants were determined, and the absolute rate constants were estimated, for halogen transfer from N,N-dihaloarenesulfonamides, (dichloroiodo)arenes, benzyl bromides, and arenesulfonyl chlorides to cyclohexyl radical and from N,N-dihaloarenesulfonamides to benzyl radical. Polar effect of the substituent was found to be the main factor determining the rate of halogen transfer from benzyl bromides and arenesulfonyl chlorides; it increases with rise in the electrophilicity of the organohalogen substrate due mainly to charge distribution in the transition state.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 33–39.Original Russian Text Copyright © 2005 by Dneprovskii, Eliseenkov, Chulkova.     

Selective and Scalable Synthesis of Trifluoromethanesulfenamides and Fluorinated Unsymmetrical Disulfides using a Shelf‐Stable Electrophilic SCF3 Reagent

The chemoselective trifluoromethylthiolation of nitrogen nucleophiles and thiols using N‐(trifluoromethylthio)phthalimide under mild, metal‐free conditions is described. A series of trifluoromethanesulfenamides and unsymmetrical disulfides is prepared from the corresponding aliphatic and aromatic amines and thiols in good yields. The reactions are operationally simple and tolerate a wide variety of functional groups. Trifluoromethanesulfenamides and disulfides belong to interesting classes of organic molecules which possess remarkable properties for medicinal and agrochemical applications.     

Reactions of N,N'-Dimethyl-N,N'-bis(trimethylsilyl)methylphosphonic Diamide with Chloral and Chloromethyldimethylchlorosilane

N,N'-Dimethyl-N,N'-bis(trimethylsilyl)methylphosphonic diamide reacts with chloral to form 1,2,3-trimethyl-4,4-dichloro-5-trimethylsiloxy-1,3,2-diazaphospholidine 2-oxide and with chloromethyldi- methylchlorosilane to form 1,2,3,4,4-pentamethyl-1,3-diaza-2-phospha-4-silacyclopentane 2-oxide.     

N,N'-Bis(3-triethoxysilyl)phthalic Diamide, N,N'-Bis(3-triethoxysilyl)malonic Damide and Derivatives

Condensation of 3-triethoxysilylpropylamine with malonic amide was studied. The condensation products, dicarboxylic acid diamides (malonic and phthalic), were used for peretherification with triethanolamine and thus new representatives of silatran series compounds were prepared: N,N'-bis(3-triethoxysilyl)malonic diamide and -phthalic diamide. By hydrolytic polycondensation of N,N'-bis(3-triethoxysilyl)malonic diamide we synthesized an organosilicon polymer with silsesquioxane structure, which we studied as a sorbent of platinum group metals rhodium, palladium and platinum. Peculiar features of sorption activity of the polymer and speculative mechanism of metal sorption are discussed.     

N,N'-Bis(3-triethylsilylpropyl)thiourea S-Dioxide and Poly[N,N'-bis(silsesquioxanylpropyl)thiourea S-Dioxide] as Reductants

The reducing power of organosilicon thiourea S-dioxides, N,N'-bis(3-triethylsilylpropyl)thiourea S-dioxide and poly[N,N'-bis(silsesquioxanylpropyl)thiourea S-dioxide], was studied. The first, monomeric dioxide readily reduces cyclohexanone to cyclohexanol. In its presence, under phase-transfer conditions, dipropyl disulfide reacts with bromobenzene to form propyl phenyl sulfide, and tellurium reacts with ethyl bromide to form diethyl telluride. The reducing power of the polymeric dioxide was demonstrated by the example of reduction of potassium permanganate. Irrespective of the medium (neutral, acidic, or alkaline), this polymer reduces Mn(VII) to Mn(IV).     

An efficient and convenient synthesis of unsymmetrical disulfides from thioacetates

We have developed convenient methods for the synthesis of functionalized unsymmetrical dialkyl disulfides under mild conditions in very good yields. The designed method is based on the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)-disulfanyl derivatives 1 with functionalized alkyl thiolate anions, generated in situ from thioacetates 2 and sodium methoxide or butylamine. The developed method allows the preparation of unsymmetrical disulfides bearing additional hydroxy, carboxy, amino, azido, biotin, or maleimide functionalities.     

Sulfonylimines of Polychloroaldehydes in Reaction with Thioamides

N-(2,2,2-Trichloroethylidene)- and N-(2-phenyl-2,2-dichloroethylidene)amides of aromatic sulfonic acids react with thioacetamide, thiourea, and N-acetylthiourea at equimolar reagents ratio to furnish N-(1-arenesulfonamido-2,2,2-trichloroethyl)- and N-(1-arenesulfonamido-2-phenyl-2,2-dichloroethyl)thioamides. The reaction with deficient amount of thiourea results in N,N'-bis(1-arenesulfonamido-2-polychloroethyl)-thiocarbamides.     

Synthesis of 4-Aryl-1,5-benzodiazepine-2-carboxamides

4,N-Diaryl-1,5-benzodiazepine-2-carboxamides were synthesized by acid-catalyzed reaction of (Z)-4,N-diaryl-2-hydroxy-4-oxo-2-butenamides with o-phenylenediamine or N,N'-bis(triphenylphosphoranediyl)-o-phenylenediamine. The reaction mechanism is discussed.     

N-Trifluoroacetyl arenesulfenamides, effective precursors for synthesis of unsymmetrical disulfides and sulfenamides

N-Trifluoroacetyl arenesulfenamides (3) were effective precursors for the synthesis of unsymmetrical disulfides (4) and sulfenamides (5). Reactions of 3 with a variety of aromatic thiols at room temperature were generally complete within 5 min and gave unsymmetrical diaryl disulfides in high yields. Aralkyl disulfides were isolated in high yields from the reaction of 3 with aliphatic thiols. The nucleophilic substitution reactions of 3 with amines proceeded smoothly and provided N-substituted sulfenamides in good to excellent yields.     

A facile synthesis of unsymmetrical heterocyclic azines by cyclodesulfurization: Reaction of methyl arylalkylidenehydrazinecarbodithioates with diamines

A new and facile synthesis of unsymmetrical heterocyclic azines is described. Methyl arylalkylidenehydraz-inecarbodithioates, prepared by the condensation of ketones or aldehydes with methyl hydrazinecarbodithioate, were heated under reflux with various diamines in ethanol. Secondary diamines, such as N,N′-dimethyl-ethylenediamine, N,N′-dimethyl-1,3-diaminopropane or N,N′-dimethyl-o-phenylenediamine, reacted smoothly with loss of hydrogen sulfide to give good yields of unsymmetrical azines. However, primary diamines, such as ethylenediamine or o-phenylenediamine, and primary/secondary diamines, such as N-methylethyl-enediamine and N-methyl-1,3-diaminopropane gave, instead, only the corresponding uncyclized thiosemi-carbazones. A cyclodesulfurization mechanism for azine formation is discussed.     

Ditocopheryl Sulfides and Disulfides: Synthesis and Antioxidant Profile

Symmetrical ditocopheryl disulfides ( Toc ) ₂ S₂ and symmetrical and unsymmetrical ditocopheryl sulfides ( Toc )₂ S were simply prepared under remarkably mild conditions with complete control of the regiochemistry by using δ-, γ-, and β-tocopheryl-N-thiophthalimides ( Toc-NSPht ) as common starting materials. The roles of sulfur atom(s), H-bond and aryl ring substitution pattern on the antioxidant profile of these new compounds, which were assembled by linking together two tocopheryl units, are also discussed.     

Stereoselective synthesis of trisubstituted alkenes containing (Z)‐allylthio units from the acetates of Baylis–Hillman adducts

A series of trisubstituted alkenes containing (Z)‐allylthio moieties as key structural units, that is, sodium (Z)‐allyl thiosulfates, symmetrical di(Z‐allyl) sulfides, and di(Z‐allyl) disulfides, unsymmetrical diallyl sulfides were prepared in moderate to good yields via chemical transformations from the acetates of Baylis‐‐Hillman adducts. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:188–198, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20394     

Electro- and Photoelectroactivity of Thin-Layer Polymers Based on [NiSalen] and [NiSalphen] Complexes

New experimental data on physicochemical properties of polymeric nickel(II) complexes with N,N'-bis(salicylidene)ethylenediamine and N,N'-bis(salicylidene)-o-phenylenediamine (including redox conductivity, photoactivity in a solution of a supporting electrolyte, and electrochemical stability) were obtained. The rate of charge transport in the polymeric matrix was studied as a function of the polymer film thickness.     

NBS‐Promoted Sulfenylation of Sulfinates with Disulfides Leading to Unsymmetrical or Symmetrical Thiosulfonates

A highly practical method to access unsymmetrical and symmetrical thiosulfonates in moderate to excellent yields has been developed through NBS‐promoted sulfenylation of sulfinates with disulfides. The present process enables the use of two RS in RSSR and shows broad functional group tolerance, which represents an atom‐economical and practical procedure for the synthesis of thiosulfonates. A plausible mechanism for the role of NBS as a promoter for the cleavage of disul?des generating N‐(organothio)succinimide that then undergos facile sulenylation with sulfinates is proposed.     

N-Acylureas in Peptide Synthesis: An X-Ray Diffraction and IR-Absorption Study

An X-ray diffraction analysts of two N-acyl derivatives of symmetrical dialkylureas, N-[N^α-(benzyloxycarbonyl)-L -valyl] -N, N′-diisopropylurea ( 1 ) and N-{Nα(tert-butyloxy)carbonyl -L -valyl}-N-N′-dicyclohexylurea ( 2 ), and one N-acyl derivative of an unsymmetrical N-N′-dialkylurea, N-[N^α-(benzyloxycarbonyl)-L -valyl] -N′-(tert-butyl)-N-ethylurea ( 3 ), has been performed. It was established that it is the least hindered O-acylisourca N-atom that attacks intramolecularly the carbonyl group of the N^α-protected amino acid activated by the unsymmetrical carbodiimide to form the major rearrangement product. The occurrence and nature of intra- and intermolecularly H? bonded forms of the N-acylureas in the crystal state were also assessed. It was also shown that soluble N-acylureas may compete with intermolecular (peptide)N? H…O?C(peptide) H-bonds in CH₂Cl₂.