E)-1Alkyl4-[2-(alkylsulfonyl)-1-ethenyl]pyridinium Salts: Reaction with Thiol Groups Giving Rise to Chromophoric (E)-1Alkyl4-[2-(alkylsulfanyl)-1-ethenyl]pyridinium Salts (original) (raw)
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The Journal of Organic Chemistry, 2007
Aliphatic thiolates were efficiently converted into the corresponding sulfenates by smooth oxidation with trans-(()-2-tert-butyl-3-phenyloxaziridine at room temperature (five examples). Subsequent electrophilic quench with benzyl bromide led to sulfoxides (S-alkylation) in good to moderate yields. Application of the protocol to an aromatic substrate was also successful. This work represents the first valuable example of the use of this poorly active oxidizing agent in synthetic organic chemistry without the need for activating conditions.
The Journal of Organic Chemistry
The behavior of cyclic thiolsulfiiates 5 and 6 (dibenzo[c,e]-l,2-dithiin 1-oxide and naphtho[l,&cd]-l,2-dithiole 1-oxide) upon treatment with either sulfite, cyanide, or t-Bus-ions has been examined and compared with the behavior of the corresponding thiolsulfonates 1 and 2 (dibemo[c,e]-1,2-dithiin and naphtho[l,&cd]-l,2-dithiole 1,l-dioxides). Very marked differences are observed. Whereas thiolsulfonates 1 and 2 are converted essentially quantitatively to ring-open substitution produds (3 and 4) upon treatment with exceas sulfite, cyanide, or t-Bus-, with thiolsulfiites 5 and 6 the equilibrium constants for opening of the sulfur-containing ring are so much smaller that only in the case of 5 and t-Bus-is the equilibrium constant large enough that a significant fraction of the thiolsulfinate is converted to the ring-opened product (7 or 8) at equilibrium. Kinetic studies of the rates of nucleophilmtalyzed racemization of optically active 5 and 6 show that the major factor reaponsible for the dramatic difference in the magnitude of the equilibrium constants is not a decrease in the rate constant for opening of the ring by the nucleophile but rather a huge increase in the rate constant for the reverse of the ring-opening reaction, which in the case of the thiolsulfinates involves displacement of the nucleophile (Nu-) from SNu by a sulfenate (SO-) group, whereas for the thiolsulfonates it is a sulfinate (SOz-) group that performs the same displacement. In the 5-t-BUS-system the rate constant for the displacement by the sulfenate is 30 OOO times faster than the rate constant for the corresponding displacement in the 1-t-Bus-system involving the sulfmate; this provides the first quantitative measure of just how much more reactive a sulfenate ion is as a nucleophile than the corresponding sulfinate. Other aspects of the kinetics of the reactions of 5 and 6 with these nucleophiles provide additional information on the behavior of 7 and 8 and their conjugate acids and thereby furnish new insight into the chemistry and reactivity and of arenesulfenates and arenesulfenic acids.
Inorganic Chemistry, 2000
The three-component reaction of ReS 4-(1), H 2 S, and unsaturated substrates (un) alkene, alkyne) affords the Re V derivatives Re(S)(S 2 un)(SH) 2-. These adducts arise via the addition of H 2 S to intermediate dithiolates ReS 2 (S 2 C 2 R 4)and dithiolenes ReS 2 (S 2 C 2 R 2)-. The species {ReS[S 2 C 2 (tms) 2 ](SH) 2 }-, [ReS(S 2 C 7 H 10)(SH) 2 ]-(3), and [ReS(S 2 C 2 H 4)(SH) 2 ]are prepared according to this route. Similarly, the selenolate-thiolate complex [ReS(S 2 C 7 H 10)(SeH)(SH)]-(5) is produced by the reaction of [ReS 2 (S 2 C 7 H 10)]with H 2 Se. The corresponding reactions using benzenethiol in place of H 2 S afford the more thermally robust adducts {ReS[S 2 C 2 (tms) 2 ](SH)(SPh)}-, [ReS(S 2 C 7 H 10)(SH)(SPh)]-(7), and [ReS(S 2 C 2 H 4)(SH)(SPh)]-. Norbornanedithiolato compounds 3, 5, and 7 are obtained as pairs of isomers that differ in terms of the relative orientation of the norbornane bridgehead relative to the RedS unit. The reaction of [ReS(S 2 C 7 H 10)(SD) 2 ]-(3-d 2) with H 2 S to give 3 is proposed to proceed via elimination of D 2 S and subsequent addition of H 2 S. Variable-temperature 1 H NMR measurements on the equilibrium of [ReS(S 2 C 6 H 12)(SPh)(SH)]with 1, 1-hexene, and PhSH gave the following results: ∆H)-7 ((1) kJ‚mol-1 ; ∆S) 23 ((4) J‚mol-1 ‚K-1. Solutions of ethanedithiol and 1 react with C 2 (tms) 2 and C 2 H 4 to give {ReS[S 2 C 2 (tms) 2 ](S 2 C 2 H 4)}and [ReS(S 2 C 2 H 4) 2 ]-, respectively, concomitant with loss of H 2 S. The pathway for the ethanedithiol reaction is examined using 2-mercaptoethanol, affording {ReS[S 2 C 2 (tms) 2 ](SC 2 H 4 OH)}-, which does not cyclize. Treatment of a solution of diphenylbutadiyne and 1 with PhSH gives two isomers of the dithiolene {ReS(SH)(SPh)[S 2 C 2 Ph(C 2 Ph)]}-. The corresponding reaction of ethanedithiol, diphenylbutadiyne, and 1 affords the 1,4-diphenylbutadiene-1,2,3,4-tetrathiolate complex {[ReS(S 2 C 2 H 4)] 2 (S 4 C 4 Ph 2)} 2- .
Journal of Pharmaceutical Research International
Aim: To systematically design, synthesize and evaluate the biological activities of new threonine-based sulfonamide derivatives in order to achieve improved drug potency. Methodology: Sulfamoyl carboxylic acids were prepared by the reaction of threonine with the appropriate sulfonyl chloride while their acetylated, carboxamide and aniline derivatives were synthesized via Lumiere-Barbier acetylation, Schotten-Baumann ammonolysis and Buchwald-Hartwig cross-coupling methods respectively. The FTIR, 1H-NMR, 13C-NMR and elemental analytical data were employed in the structural characterization. In vitro and in silico antioxidant and antimicrobial studies were carried out. Results: Compounds 1b and 1d displayed the best in vitro antibacterial activities against Escherichia coli, Salmonella typhi, Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and antifungal activities against Candida albican sand Aspergillus niger. Compound 1f (IC50 = 1.150±0.003 µg/ml) exhibited the bes...