Reactions of Phthalimide and Potassium Phthalimide With Sulfur Monochloride

Kalnins, Malda V.

doi:10.1139/v66-318

Cited by 32 publications

(12 citation statements)

References 5 publications

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“…Fmoc‐[ 13 C 3 , 15 N]Cys(Trt)‐OH was supplied by Cambridge Isotope Laboratories and [ 13 C 3 ]PyvONa was obtained from Sigma‐Aldrich. N , N ′‐thiobisphthalimide, β‐chloroalanine and Fmoc‐Sec(Mob)‐OH were synthesized according to the published procedures. Analytical RP‐HPLC for synthetic work was carried out on a Waters analytical system consisting of a Waters 600 Controller, a Waters 2487 dual absorbance UV detector and a 717plus Autosampler with Empower 2 software package.…”

Section: Methodsmentioning

confidence: 99%

On the mechanism of degradation of oxytocin and its analogues in aqueous solution

Wiśniewski¹,

Finnman²,

Flipo³

et al. 2013

Biopolymers

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Oxytocin (OT) is a cyclic nonapeptide containing one internal disulfide bond between its Cys(1) and Cys(6) residues. Although OT is one of the most commonly used peptidic drugs, the mechanism of its degradation in aqueous solution and the identity of its degradants have not been fully elucidated. To investigate the pathways and products of OT degradation in slightly acidic to neutral solutions, we prepared the peptides: OT, [D-Cys(1)]OT, a series of N-alkylated OT analogues, [[(13)C3,(15) N]Cys(1)]OT, and OT where each sulfur atom was systematically replaced by either methylene, (34)S, or Se. The peptides were incubated at 40°C and the degradation products studied by HPLC, LCMS, and (13)C-NMR. Our findings suggest that the degradation begins with β-elimination of the disulfide linkage to form a putative intermediate linear peptide containing an S-thiocysteine (a persulfide) in position 6 and a dehydroalanine in position 1. This intermediate persulfide appears to donate a sulfur atom to an intact OT molecule to form OT trisulfide and higher monomeric polysulfides, while the dehydroalanine residue is hydrolyzed with loss of the N-terminal amino group to yield a linear N-pyruvoylated octapeptide containing a reduced Cys(6). Based on the MS and (13)C-NMR data of the products from degradation of [[(13)C3,(15)N]Cys(1)]OT, we postulate that the ultimate degradation products of OT are dimers composed of two pyruvoylated octapeptides held together by one disulfide bridge between the two Cys(6) residues and by one more, non-reducible, linkage resulting from an aldol-type condensation between the two N-terminal pyruvoyl groups.

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Section: Methodsmentioning

confidence: 99%

On the mechanism of degradation of oxytocin and its analogues in aqueous solution

Wiśniewski¹,

Finnman²,

Flipo³

et al. 2013

Biopolymers

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“…A literature procedure was followed with slight modifications. 58 To a solution of phthalimide (7.1 g, 48.3 mmol) dissolved in DMF (40 mL), sulfur monochloride (6.4 g, 47.4 mmol) was added. The contents were stirred for 16 h. The white precipitate was collected by vacuum filtration and washed with toluene (10 mL) to give the product in a 75% yield (5.9 g).…”

Section: Methodsmentioning

confidence: 99%

Stabilities of Three Key Biological Trisulfides with Implications for Their Roles in the Release of Hydrogen Sulfide and Bioaccumulation of Sulfane Sulfur

Brown

Bowden

2022

ACS Omega

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Trisulfides and higher polysulfides are important in the body due to their function as key reservoirs of sulfane sulfur and their rapid reactions to release persulfides. Recent work has shown that persulfides act as powerful antioxidants and release hydrogen sulfide, an emerging gasotransmitter with numerous therapeutic effects. Despite the important role of polysulfides, there is a lack of understanding of their stabilities in aqueous systems. To investigate the reactivity of trisulfides and polysulfides, three key biologically important trisulfides were synthesized from cysteine, glutathione, and N -acetylcysteine, and the tetrasulfide of N -acetylcysteine was synthesized as a representative polysulfide. The stabilities of sulfides were monitored in buffered D 2 O using 1 H NMR spectroscopy under a range of conditions including high temperatures and acidic and alkaline environments. The tri- and tetrasulfides degraded rapidly in the presence of primary and tertiary amines to the corresponding disulfide and elemental sulfur. The half-lives of N -acetylcysteine tri- and tetrasulfides in the presence of butylamine were 53 and 1.5 min, respectively. These results were important because they suggest that tri- and tetrasulfide linkages are short-lived species in vivo due to the abundance of amines in the body. Under basic conditions, cysteine and glutathione trisulfides were unstable due to the deprotonation of the ammonium group, exposing an amine; however, N -acetylcysteine trisulfide was stable at all pH values tested. Hydrogen sulfide release of each polysulfide in the presence of cysteine was quantified using a hydrogen sulfide-sensitive electrode and 1 H NMR spectroscopy.

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“…46 Of note here is that the original work on the reaction of SCl 2 or S 2 Cl 2 with phthalimide dates back to Kuverji Naik in 1921. 48 However, his assignment of structure was questioned by Malda Kalnins 49 in the 1960s, who established that the outcome for producing (PhthN) 2 S versus (PhthN) 2 S 2 with S 2 Cl 2 is solvent dependent.…”

Section: Review Synopenmentioning

confidence: 99%

A Review of Heterolytic Synthesis Methodologies for Organotri- and Organotetrasulfane Synthesis

Ali

Amer

Petersen

et al. 2021

SynOpen

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It has been ten years since the last comprehensive review on polysulfanes, and during the intervening period, organodi-, organotri- and organotetrasulfanes have featured prominently in both the chemistry and biology literature. This timely update presents both a mechanistic and historical account of synthesis methodology available for organotri- and organotetrasulfanes involving heterolytic S–S bond formation.

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Reactions of Phthalimide and Potassium Phthalimide With Sulfur Monochloride

Cited by 32 publications

References 5 publications

On the mechanism of degradation of oxytocin and its analogues in aqueous solution

On the mechanism of degradation of oxytocin and its analogues in aqueous solution

Stabilities of Three Key Biological Trisulfides with Implications for Their Roles in the Release of Hydrogen Sulfide and Bioaccumulation of Sulfane Sulfur

A Review of Heterolytic Synthesis Methodologies for Organotri- and Organotetrasulfane Synthesis

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