Versatility and the mechanism of the n-butyl-amine-catalyzed reaction of thiols with sulfur

Vineyard, B. D.

doi:10.1021/jo01287a024

Cited by 59 publications

(42 citation statements)

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“…In the colorless mixtures of 1 þ PhSSPh, thiophenol was not present, but if it were present in undetectable amounts, it would have helped to open the S 8 ring in the presence of triethylamine [30,31]. Control experiments showed that solutions of octasulfur in chloroform containing increasing amounts of thiophenol produced yellow to orange colors when triethylamine was added, indicating that polysulfides had been formed by ring opening of S 8 by the thiophenolate anion [30].…”

Section: The Reaction Of Me 2 Asà àSph (1) With S 8 /Et 3 Nmentioning

confidence: 99%

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The reactions of triethylamine-activated octasulfur with thioarsinites, L₂As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me₂As(S)‒S‒AsMe₂, and triphenylarsine

Sideris¹,

Tsivgoulis²,

Vachliotis³

et al. 2009

Main Group Chemistry

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The reactions of L 2 AsÀ ÀSPh (L ¼ Me or Ph) with varying amounts of octasulfur, activated by triethylamine, aiming at the preparation of L 2 AsÀ ÀSÀ ÀAsL 2 and L 2 As(S)À ÀSÀ ÀAsL 2 were slow and very complex in the sense that the composition in solution changed on work up. Generally, the disulfide L 2 As(S)À ÀSÀ ÀAsL 2 was formed admixed with L 2 AsÀ ÀSÀ ÀNEt 3 þ and L 2 AsÀ ÀS 7 . The disulfide Ph 2 As(S) À ÀSÀ ÀAsPh 2 was not stable during chromatography giving sulfur (S 8 ) and Ph 2 AsÀ ÀSÀ ÀAsPh 2 which was autoxidized to Ph 2 AsO 2 HÁPh 2 As(S)OH. Bunsen's cacodyl disulfide, Me 2 As(S)À ÀSÀ ÀAsMe 2 , was electrophilic toward activated octasulfur reacting at As¼S sulfur. Triphenylarsine was oxidized to pure triphenylarsine sulfide in boiling ethanol by octasulfur in the presence of a catalytic amount of triethylamine in short time and with excellent yields.

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Section: The Reaction Of Me 2 Asà àSph (1) With S 8 /Et 3 Nmentioning

confidence: 99%

“…Control experiments showed that solutions of octasulfur in chloroform containing increasing amounts of thiophenol produced yellow to orange colors when triethylamine was added, indicating that polysulfides had been formed by ring opening of S 8 by the thiophenolate anion [30].…”

Section: The Reaction Of Me 2 Asà àSph (1) With S 8 /Et 3 Nmentioning

confidence: 99%

The reactions of triethylamine-activated octasulfur with thioarsinites, L₂As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me₂As(S)‒S‒AsMe₂, and triphenylarsine

Sideris¹,

Tsivgoulis²,

Vachliotis³

et al. 2009

Main Group Chemistry

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“…In the starting esters 1a-1c and 2a, thiophenol was not present, but if it were present in undetectable amounts, it would have helped to open the octasulfur ring in the presence of triethylamine [24,25]. Control experiments showed that solutions of octasulfur in chloroform containing increasing amounts of thiophenol produced yellow to orange colors when triethylamine was added, indicating that polysulfides have been formed by ring opening of octasulfur by the thiophenolate anion [24].…”

Section: Substrates and Uncatalysed Reactionsmentioning

confidence: 99%

On the Reaction of Dithioarsonites, L‐As(SPh)₂ (L = Ar, R), with Octasulfur in the Presence of Triethylamine as an Activator. The Crystal Structure of the Sesquisulfide (2‐O₂N‐C₆H₄‐As)₂S₃

Terzis

Ioannou

2004

Zeitschrift anorg allge chemie

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Octasulfur (elemental sulfur) does not react at room temperature with a variety of As III compounds of the type Ar-As(SPh) 2 and R-As(SPh) 2 . However, in the presence of catalytic amounts of triethylamine, which probably acts as an activator of octasulfur, reactions do take place. The products isolated from the aromatic dithioarsonites are not the expected Ar-As(S)(SPh) 2 but the sulfide, cyclo-(PhAsS) 4 , and the sesquisulfides, (ArAs) 2 S 3 , which are the same with those obtained by reduction of arylarsonic acids with hydrogen sulfide. The action of S 8 /Et 3 N on aliphatic dithioarsonites did not give any As V products but gave mixtures of non-separable Inhaltsübersicht. S 8 (elementarer Schwefel) reagiert bei Raumtemperatur nicht mit einer Reihe von As III -Verbindungen des Typs Ar-As(SPh) 2 und R-As(SPh) 2 . Jedoch erfolgen Reaktionen in Gegenwart von katalytischen Mengen von Triethylamin, die wahrscheinlich als Aktivator des S 8 wirken. Die isolierten Produkte aus der Reaktion der aromatischen Dithioarsenite sind aber nicht das erwartete Ar-As(S)(SPh) 2 sondern die Sulfide cyclo-(PhAsS) 4 und die Sesquisulfide, (ArAs) 2 S 3 , die denen gleichen, die bei der Reduktion von Arylarsenitsäuren mit Schwefelwasserstoff erhalten werden.

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“…20 However, it has been reported that this enzyme can act as an HS − :O 2 oxidoreductase that converts HS − and O 2 into H 2 O 2 and S (Eqn 10, where S is defined as elemental sulfur and related species in which sulfur is bonded to sulfur). 58 Under the reaction conditions employed here, elemental sulfur, in the form S 8 , is expected 17,59 to react with thiol to generate additional persulfides (RS x S − ) that, in turn, generate additional superoxide radical. In addition, Cu,Zn-SOD has the potential to act as an oxidase that converts thiols in the assay mixture to disulfide and H 2 O 2 .…”

mentioning

confidence: 99%

Possible chemical mechanisms underlying the antitumor activity of S-deoxyleinamycin

Sivaramakrishnan

Gates

2008

Bioorganic & Medicinal Chemistry Letters

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Though less potent than the parent natural product leinamycin, S-deoxyleinamycin displays activity against human cancer cell lines that is comparable to many clinically-used agents. The results reported here suggest that the 1,2-dithiolan-3-one heterocycle found in S-deoxyleinamycin reacts with thiols to generate a persulfide intermediate (RSS − ) that could deliver biologically active polysulfides, hydrogen sulfide, and reactive oxygen species (O 2 • − , H 2 O 2 , and HO•) to the interior of cells.Leinamycin (1) is a structurally interesting natural product that displays impressive, nanomolar IC 50 -values against human cancer cell lines. 1-5 Reaction of thiols with leinamycin leads to ejection of a persulfide intermediate (2) that generates cell-killing reactive oxygen species (Scheme 1). [6][7][8][9] In addition, the 1,2-oxathiolan-5-one derivative (3) formed in this reaction undergoes further rearrangement to an episulfonium ion (4) that efficiently alkylates guanine residues in duplex DNA. 6,10 The resulting 7-alkylguanine residues undergo rapid depurination to generate a burst of cytotoxic abasic sites in duplex DNA. [11][12][13] The reaction with thiols may be central to the potent biological activity of leinamycin because cells contain millimolar concentrations of the thiol-containing tripeptide glutathione 14 that can trigger the release of cell killing reactive intermediates from this natural product.In light of the central role played by leinamycin's sulfoxide oxygen in the generation of cytotoxic reactive intermediates (Scheme 1), it is not surprising that S-deoxyleinamycin (5) is markedly less cytotoxic than leinamycin. For example, 5 displays an IC 50 value of 4 μM against HeLa S3 cells, whereas that for leinamycin is 27 nM. 3 Despite its diminished cytotoxicity relative to leinamycin, it is important to note that the activity of 5 is comparable to some clinically-used anticancer drugs. 15 Accordingly, studies of 5 have the potential to reveal new chemical processes by which organic molecules can elicit anticancer activity.Previous work has shown that 5 does not cause thiol-triggered DNA alkylation; 3 however, our previous experience with related sulfur heterocycles [16][17][18][19] led us to consider the possibility that reactions of thiols with the 1,2-dithiolan-3-one heterocycle in 5 might lead to the generation of superoxide radical (O 2 • − ). Under physiological conditions, superoxide radical decomposes to hydrogen peroxide and, ultimately, hydroxyl radical as shown in the (unbalanced) Eqns 4 -5, where M represents a transition metal such as iron or copper. 20 Intracellular production of *Corresponding author. Tel.: +1-573-882-6763; fax: +1-573-882-2754, e-mail gatesk@missouri.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in ...

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Versatility and the mechanism of the n-butyl-amine-catalyzed reaction of thiols with sulfur

Cited by 59 publications

References 2 publications

The reactions of triethylamine-activated octasulfur with thioarsinites, L₂As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me₂As(S)‒S‒AsMe₂, and triphenylarsine

The reactions of triethylamine-activated octasulfur with thioarsinites, L₂As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me₂As(S)‒S‒AsMe₂, and triphenylarsine

On the Reaction of Dithioarsonites, L‐As(SPh)₂ (L = Ar, R), with Octasulfur in the Presence of Triethylamine as an Activator. The Crystal Structure of the Sesquisulfide (2‐O₂N‐C₆H₄‐As)₂S₃

Possible chemical mechanisms underlying the antitumor activity of S-deoxyleinamycin

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Versatility and the mechanism of the n-butyl-amine-catalyzed reaction of thiols with sulfur

Cited by 59 publications

References 2 publications

The reactions of triethylamine-activated octasulfur with thioarsinites, L2As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me2As(S)‒S‒AsMe2, and triphenylarsine

The reactions of triethylamine-activated octasulfur with thioarsinites, L2As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me2As(S)‒S‒AsMe2, and triphenylarsine

On the Reaction of Dithioarsonites, L‐As(SPh)2 (L = Ar, R), with Octasulfur in the Presence of Triethylamine as an Activator. The Crystal Structure of the Sesquisulfide (2‐O2N‐C6H4‐As)2S3

Possible chemical mechanisms underlying the antitumor activity of S-deoxyleinamycin

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The reactions of triethylamine-activated octasulfur with thioarsinites, L₂As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me₂As(S)‒S‒AsMe₂, and triphenylarsine

The reactions of triethylamine-activated octasulfur with thioarsinites, L₂As‒SPh (L = Me, Ph), Bunsen's cacodyl disulfide, Me₂As(S)‒S‒AsMe₂, and triphenylarsine

On the Reaction of Dithioarsonites, L‐As(SPh)₂ (L = Ar, R), with Octasulfur in the Presence of Triethylamine as an Activator. The Crystal Structure of the Sesquisulfide (2‐O₂N‐C₆H₄‐As)₂S₃