Oxygen-containing Nucleophiles Research Articles

Photolysis of Trenbolone Acetate Metabolites in the Presence of Nucleophiles: Evidence for Metastable Photoaddition Products and Reversible Associations with Dissolved Organic Matter.

Photolysis of trenbolone acetate (TBA) metabolites in the presence of various nitrogen-, sulfur-, or oxygen-containing nucleophiles (e.g., azide, ammonia, or thiosulfate, respectively) results in rapid (half-lives ∼20-60 min), photochemically induced nucleophile incorporation across the parent steroid's trienone moiety. The formation of such nucleophile adducts limits formation of photohydrates, suggesting competition between the nucleophile and water for photochemical addition into the activated steroid structure. Analogous to previously reported photohydration outcomes, LC/MS analyses suggest that such photonucleophilic addition reactions are reversible, with more rapid elimination rates than thermal dehydration of photohydrates, and regenerate parent steroid structures. Beyond photonucleophilic addition pathways, we also found that hydroxylamine and presumed nucleophilic moieties in model dissolved organic matter (DOM; Fluka humic acid) can react via thermal substitution with TBA metabolite photohydrates, although this reaction with model DOM was only observed for photohydrates of trendione. Most nucleophile addition products [i.e., formed via (photo)reaction with thiosulfate, hydroxylamine, and ammonia] are notably more polar relative to the parent metabolite and photohydration products. Thus, if present, both nucleophilic adducts and bound residues in organic matter will facilitate transport and help mask detection of TBA metabolites in surface waters and treatment systems.

Catalyst-free fluorinative alkoxylation of alkenes

The fluorinative alkoxylation of simple alkenes under catalyst-free conditions was achieved. Various substituted olefins, including terminal and internal alkenes, and oxygen-containing nucleophiles were compatible with the standard conditions, and gave a variety of β-fluoroethers in good to excellent yields. Notably, the alkynyl and chloride-containing nucleophiles were well tolerated. In addition, acetic acid and TsNH2 could be also used as nucleophiles and successfully afforded the desired products in good yields.

One-pot synthesis, characterization, and antioxidant capacity of sulfur- and oxygen-substituted 1,4-naphthoquinones and a structural study

In the present study, we reported the one-pot synthesis of S,S- and S,O-substituted 1,4-naphthoquinones, their structural studies, and investigation of their antioxidant activity. The multicomponent reactions of 2,3-dichloro-1,4-naphthoquinone with sulfur- and oxygen-containing nucleophiles were investigated to obtain highly functionalized S,S- and S,O-substituted 1,4-naphthoquinone derivatives. All new compounds were characterized on the basis of 1H, 19F, and 13C nuclear magnetic resonance spectroscopy, mass spectrometry, and Fourier transform infrared spectroscopy. Crystal structure of 2,3-dihydro-2-(hydroxymethyl)naphtho[2,3-b]-1,4-oxathiin-5,10-dione was determined by X-ray diffraction method. The synthesized compounds were screened for their antioxidant capacity and free radical scavenging activity using the cupric reducing antioxidant capacity method and DPPH method, respectively. 3-Chloro-2-[3-(3-chloro-1,4-dihydro-1,4-dioxonaphthalen-2-yloxy)propylsulfanyl]-1,4-naphthoquinone shows the highest antioxidant capacity with 0.63 cupric reducing antioxidant capacity—trolox equivalent antioxidant capacity coefficient.

Hydrogen peroxide-or sodium hypochlorite-induced bromination of 1-arylbut-2-enes

Bromination of 1-arylbut-2-enes in the system [HBr or NaBr (KBr)-HX]-H2O2 (or NaOCl) under relatively mild conditions leads to electrophilic addition of bromine or hypobromous acid at the side-chain double bond. Under more severe conditions, the process is accompanied by bromination of the aromatic ring. Treatment of the title compounds with peroxy acids (RCOOH-H2O2) gives the corresponding epoxy derivatives which react with HBr and oxygen-containing nucleophiles to produce α-bromo alcohols, diols, and diol acetates.

Thienooxazolopyrimidinium Salts. Reaction of 1‐Bromomethyl‐5‐oxo‐4‐phenyl‐1,2,4,5,6,7,8,9‐octahydro[1]benzothieno [3,2‐e][1,3]oxazolo[3,2‐a]pyrimidin‐11‐ium Bromide with Oxygen‐Centered Nucleophiles.

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Thienooxazolopyrimidinium salts. Reaction of 1-bromomethyl-5-oxo-4-phenyl-1,2,4,5,6,7,8,9-octahydro[1]benzothieno-[3,2-e][1,3]oxazolo[3,2-a]pyrimidin-11-ium bromide with oxygen-centered nucleophiles

Reactions of [1]benzothieno[3,2-e][1,3]oxazolo[3,2-a]pyrimidin-11-ium bromide with oxygen-containing nucleophiles involve opening of the dihydrooxazole ring and lead to the formation of new functionally substituted thieno[2,3]-d]pyrimidine derivatives.

Reactions of alicyclic epoxy compounds with oxygen-centered nucleophiles

The review analyzes the reactions of alicyclic epoxy compounds with oxygen-containing nucleophiles (alcohols, water, and organic acids), describes biologically active products of these reactions, and discusses their mechanisms and results of their simulation by quantum-chemical methods. The regio-and stereoselectivity of nucleophilic reactions of epoxy compounds and the activation of epoxy ring by achiral and chiral catalysts are also considered.

Design of Polyaromatic Ethers Using Cyclopentadienyliron Complexes

Nucleophilic aromatic substitution of cyclopentadienyliron complexes of chloroarenes with oxygen-containing nucleophiles led to the isolation of a number of aromatic ether complexes (2, 5a−e) in very good yields. Reactions of these complexes with 1-naphthol, followed by removal of the cyclopentadienyliron moieties produced aromatic ether compounds with terminal naphthoxy groups (3, 7a−e). Polymerization of these monomers in the presence of ferric chloride gave the poly(aryl ethers) 4 and 8a−e. These materials were obtained with weight-average molecular weights up to 139 900 g/mol. Thermogravimetric analysis of the poly(aryl ethers) showed that these materials displayed no significant weight loss until 458−575 °C. The glass transition temperatures for these polymers ranged from 147 to 226 °C, as measured by differential scanning calorimetry.

Synthesis of (4-chlorophenyl)-(1-oxo-1λ 4-benzo[b]thien-2-yl)methanone and study of its reactivity towards sulfur- and oxygen-containing nucleophiles

(4-Chlorophenyl)-(1-oxo-1λ 4-benzo[b]thien-2-yl)methanone 2a was synthesized by oxidation of the corresponding benzo[b]thiophene derivative 2 with the oxidative system H 2O 2 TFA . This benzo[b]thiophene sulfoxide undergoes Michael-type nucleophilic addition of sulfur- and oxygen-containing nucleophiles either under basic conditions leading to 2,3-dihydro-3-substituted-benzo[b]-thiophene 1-oxides or in acidic media leading then to rearomatized 3-substituted-benzo[b]thiophenes. This method provides an easy two-step functionalization of 2-acyl-benzo[b]thiophene derivatives.

Breaking and making of the S–S linkage via nucleophilic substitution.: An ab initio study

The energetics of nucleophilic opening and closing of protonated disulphide bridges has been studied for the case of two sulphur-containing (H 2S and CH 3SH) nucleophiles. The energetics of this reaction was compared to that of the nucleophilic opening and closing of disulphide bridges with thiolate ions: In the former case a not so good nucleophile is combined with an excellent leaving group, and in the latter case a superior nucleophile is combined with a relatively poor leaving group. The barrier heights for these S N2-type reactions were found to be comparable as calculated by ab initio MO methods. In addition, two oxygen-containing nucleophiles (H 2O, HCONH–CH[CH 2OH]–CONH 2) have also been studied in the following reaction: The water molecule is not nucleophilic enough to open the disulphide bridge. However, in a serine residue, in which the oxygen of the side-chain OH group is activated through backbone/side-chain hydrogen bonding, the hydroxy group is sufficiently nucleophilic to open the disulphide bridge, just like the sulphur-containing nucleophiles mentioned above.

Synthesis, reaction, and cytotoxicity of novel propargylic sulfones

Abstract Propargylic sulfones 1 and 2 have been synthesized for their potent interactions with DNA. The crown ether conjugate 8 was also prepared from 1 under carefully established reaction conditions. The synthesized propargylic sulfones 2, 5, and 8 exhibited high reactivity toward sulfur-, nitrogen-, and oxygen-containing nucleophiles. Compound 1 showed an IC50 of 5.3×10−6 M against KB/P cancer cells comparable with that of the clinically used agent 5-FU.

Ethynyl carbonium ions. 1. Reaction of 2.6-diaryl-4-phenylethynylpyrulium perchlorates with oxygen-containing nucleophiles

When 2,6-diaryl-4-phenylethynylpyrylium perchlorates are refluxed in water, methanol, or ethanol, they are converted to monomethinecyanines, the formation of which is explained by hydration of the phenylethynyl group and subsequent [2+2]-cycloaddition of the resulting 2,6-diaryl-4-benzoylmethylenepyrans to the starting pyrylium salt. The corresponding pyridine derivatives were obtained by the action of ammonia and aniline on the monomethinecyanines. The IR and PMR spectra of the compounds and the results of x-ray diffraction analysis of 2,6-diphenyl-4-[1′-(2″,6″-diphenyl-4″-pyranylidene)-2′-phenyl-3′-benzoylallyl]pyridine are presented.

Some new highly substituted trifluoromethyl sulfuranes

Abstract trans-Chlorotetrafluoro(trifluoromethyl)sulfur(VI), CF3SF4Cl, readily undergoes reductive defluorination to sulfur(IV)-containing compounds when it is reacted with nitrogen- or oxygen-containing nucleophiles. Thus, CF3S(NR2)2Cl results from a variety of nitrogen bases, such as R2NH = piperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, morpholine, 3,5-dimethylmorpholine, and N,N'-dimethylethenediamine. With alcohols, CF3S(ORf)2Cl is formed where RfOH = 2,2,2-trifluoroethanol and 1,1,1-trifluoro-2-propanol. Due to the low stability of all of these compounds, complete characterization was difficult.

5-membered cyclic acyl phosphates : A new class of extremely reactive phosphorylating agents

The reaction of phosgene with the oxyphosphorane made from biacetyl and trimethyl phosphite gives an α-(dimethylphosphato)-β-ketoacid chloride, which undergoes an intramolecular loss of methyl chloride under catalysis; by CuSO 4, and yields the first reported 5-membered cyclic acyl phosphate. The acyl phosphate is attacked exclusively at phosphorus by water, alcohols and phenols, at an extraordinarily rapid rate. In contrast, tertiary amines attack only the Me carbon of the exocyclic OMe group of the acyl phosphate to give quaternary ammonium salts of 5-membered cyclic acyl phosphates. These cyclic mixed anhydrides of phosphoric acid are the most powerful phosphorylating agents for oxygen-containing nucleophiles known at present. The end-products of the phosphorylations are phosphotriesters, phosphodiesters, and phosphomonoesters, containing the easily removable acetoinyl group, [(CH 3CO)(CH 3)CHO]P(O)(OR)(OR′).

3-Heteraglutaraldehydes. Part II. Tetrahydrothiophen-3,4-diol 1,1-dioxides and the chemistry of their oxidation product, 3-thiaglutaraldehyde 3,3-dioxide, and its derivatives

Reproducible methods are described for the preparation of 3,4-epoxytetrahydrothiophen 1,1-dioxide and trans-tetrahydrothiophen-3,4-diol 1,1-dioxide by acid-catalysed reactions of 2,5-dihydrothiophen 1,1-dioxide with hydrogen peroxide. Earlier confusing accounts of the effect of acetic and formic acids have been clarified. The trans- as well as the more reactive cis-diol was oxidised by periodate to 2,2′-sulphonyldiacetaldehyde. In reaction with nitrogen-, sulphur-, or oxygen-containing nucleophiles, the dialdehyde formed crystalline linear derivatives and the only cyclic compounds readily obtained were 2-acetoxy-6-phenylthio-1,4-oxathian 4,4-dioxide and 1,4-dithian-2,6-diol 4,4-dioxide. 2,2′-Sulphonyldi(acetaldehyde oxime) was dehydrated to sulphonyldiacetonitrile, also prepared by oxidation of the known thiodiacetonitrile. An alternative approach to the dialdehyde by addition of sulphuryl chloride to ethyl vinyl ether was unsuccessful.