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Sulfonyl Group (sulfonyl + group)
Selected AbstractsLaser Flash Photolysis of Disulfonyldiazomethanes: Partitioning between Hetero-Wolff Rearrangement and Intramolecular Carbene Oxidation by a Sulfonyl GroupEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2003Götz Bucher Abstract Laser flash photolysis of bis(phenylsulfonyl)diazomethane (1a) and ditosyldiazomethane (1b) leads to the formation of sulfonylsulfenes 8a/8b (,max = 310 nm). Non-first-order kinetics and non-linear Stern,Volmer behavior suggest the formation of another transient species also absorbing at , = 310 nm. Based on the results of DFT calculations, these species are tentatively identified as dithiocarbonate S,S,S, -trioxides 12a/b, which are formed from the oxathiirene S -oxides 9a/b. The latter compounds bear the characteristics of masked carbenes (, estimated as 700 ps) and are quenched by methanol and cyclooctene. Singlet disulfonylcarbenes 2a/b are not predicted to be minima, since all attempts at optimizing the geometry of 2a led to 9a instead. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Broadening the Synthetic Scope of the Iron(III)-Catalyzed Aza-Prins CyclizationEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2010Rubén M. Carballo Abstract The nature and influence of the N -sulfonyl group in aza-Prins cyclization and the reactivity of the six-membered aza-cycle generated has been studied. The aza-Prins cyclization of ,,,-unsaturated amines with a tosyl group at the nitrogen atom produces 2-alkyl-4-halo-1-tosyl-1,2,5,6-tetrahydropyridines with a halovinyl function, extraordinarily stable to further derivatization and detosylation conditions. To modulate the reactivity of such aza-cycles, a general study of the aza-Prins cyclization reaction was performed with several sulfonamides. Ring formation occurs satisfactorily with both N -nosyl and N -mesylamines providing optimal conditions for further synthetic transformations. To exemplify the scope of this methodology, a short synthesis of the alkaloid coniine was successfully carried out. [source] The First Reaction of Dimethoxycarbene with an Imine MoietyHELVETICA CHIMICA ACTA, Issue 9 2007Grzegorz Mlosto Abstract The nucleophilic dimethoxycarbene (DMC; 2) generated by thermal decomposition of 2,5-dihydro-1,3,4-oxadiazole derivative 1 in boiling toluene reacts smoothly with N -(9H -fluoren-9-ylidene)-4-methylbenzenesulfonamide (7b) to yield carbonimidoate derivative 10. A multi-step reaction pathway, initiated by the attack of DMC onto the CN bond and followed by the migration of the sulfonyl group (or via a sulfinate anion) is proposed to explain the formation of the final product. In contrast to the formal ketimine 7b, N -benzylidene-4-methylbenzenesulfonamide (7a), a formal aldimine, does not react with DMC under comparable conditions. [source] Synthesis and Reactivity of , -Electron-Deficient (Arylsulfonyl)acetatesHELVETICA CHIMICA ACTA, Issue 12 2002Diego Different , -electron-deficient (arylsulfonyl)acetates 9 were synthesized (Scheme,1, Table,1), and their behavior as soft nucleophiles in the dialkylation reaction under phase-transfer catalysis conditions was studied (Schemes,2 and 3, Tables,2 and 3). The [3,5-bis(trifluoromethyl)phenyl]sulfonyl group was shown to be the best substituent for the stereoselective synthesis of (E)-aconitates 18via an alkylation hydro-sulfonyl-elimination integrated process under very mild phase-transfer-catalysis conditions (Scheme,5, Table,4). Sulfonylacetates 9h,i also underwent smooth Diels-Alder reactions with acyclic and cyclic dienes via in situ formation of the appropriate dienophile through a Knoevenagel condensation with paraformaldehyde (Scheme,6). Reductive desulfonylation with Zn and NH4Cl in THF was shown to be an efficient method for removal of the synthetically useful sulfonyl moiety (Scheme,7). [source] Gas-phase-assisted surface polymerization of methyl methacrylate with Fe(0)/TsCl initiator systemJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Yoshito Andou Abstract To obtain a high polymer coated Fe(0) surface, gas-phase-assisted surface polymerization (GASP) of methyl methacrylate (MMA) was investigated using a zero-valent iron (Fe(0))/p -toluene sulfonylchloride (TsCl) initiator system, resulting in successful high polymer production on the solid surface. GASP was found to be initiated by radical species that might have been generated via redox reactions with Fe(0), Fe(II), Fe(III), and TsCl. From 1H-NMR analysis, the p -toluene sulfonyl group was found at one end of the polymer chain. The molecular weight of obtained PMMA drastically decreased with increase in the composition ratio of Fe(0) in the initiator system, and increased with increase in polymer yield. From the results, it was assumed that the physically controlled polymerization of MMA proceeded by immobilized active species at gas,solid interfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1879,1886, 2007 [source] Preparation of new N6, 9-disubstituted 2-phenyl-adenines and corresponding 8-azaadenines.: A feasibility study for application to solid-phase Synthesis.JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2004A suitably substituted pyrimidine 1 was converted to a number of title compounds. Nucleophilic substitu tion involving the chlorine atoms in 1 by treatment with phenylmethanethiol yielded 2 or 3, depending on the reaction temperature. Treatment of 3 with an amine afforded 6-phenylmethanesulfanyl-N4 -substituted-2-phenyl-pyrimidine-4,5-diamines 4,7. These pyrimidines were converted into 2-phenylpurines 8,11 and 2-phenyl-8-azapurines 12,14, by treatment with triethyl orthoformate in the presence of hydrochloric acid (or acetic anhydride), or with potassium nitrite and acetic acid respectively. The thioether function on C(6) was then converted into a sulfonyl group by oxidation with m -chloroperoxybenzoic acid affording purines 15,18 and their 8-azaanalogs 19,21; these compounds, as crude products, were treated with an amine to yield the corresponding adenines 22,25 or 8-azaadenines 26,31. All reactions were performed under conditions com patible with the possible use of a thiomethyl resin in place of phenylmethanethiol to bind the pyrimidine ring of 1 to a solid phase. [source] Computational study of base-induced skeletal conversion via a spirocyclic intermediate in dibenzodithiocinium derivatives by ab initio MO calculationsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 5 2003Keiji Okada Abstract Reaction of 6-methyl-12-oxo-5H,7H -dibenzo[b,g][1,5]dithiocinium salt (1-SO) with methanolic KOH afforded a mixture of dibenzothiepin derivatives 2-SO. In order to clarify the intermediates of the rearrangement, ab initio MO calculations with the HF/6,31G* basis set were performed on the reaction intermediates, the transition states and related compounds. The rearrangement was explained in terms of the usual [2,3]-sigmatropic shift via a spirocyclic intermediate, followed by a 1,3-shift of the sulfonyl group. However, a different type of rearrangement was observed in 6-methyl-5H,7H -dibenzo[b,g][1,5]dithiocinium salt (1-S), giving an unexpected dibenzothiepin derivative 3-S along with a small amount of a ring-opening product 8 under the same reaction conditions. The formation of 3-S and 8 was understandable by the assumption of a cationic intermediate resulting from heterolytic cleavage at the benzyl position. Copyright © 2003 John Wiley & Sons, Ltd. [source] Computer-aided design of selective COX-2 inhibitors: comparative molecular field analysis and docking studies of some 3,4-diaryloxazolone derivativesJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 7 2001G. R. Desiraju Abstract The recent discovery of a second, inducible isoform of cyclooxygenase, COX-2, has stimulated the search for highly selective non-steroidal anti-inflammatory drugs (NSAIDs). These NSAIDs have the ability to treat pain and inflammation caused by arthritis with less risk of gastrointestinal or renal toxicity. We report here the results of 3D-quantitative structure,activity relationship and docking studies, performed on a series of 3,4-diaryloxazolones. Comparative moleculer field analysis studies provided a good model with cross-validated and conventional r2 values of 0.688 and 0.969 respectively for 24 analogues in the training set with six components. Docking studies with both COX-1 and COX-2 indicate good selectivity for COX-2. The binding energies between COX-2 and some of the most active oxazolones are comparable to those of celecoxib or rofecoxib. These compounds adopt similar orientations and form similar sets of hydrogen bonds involving the sulfonyl group of the ligand and His 90, Leu 352, Ser 353, Arg 513, Phe 518 and Ser 530 residues of the receptor. Copyright © 2001 John Wiley & Sons, Ltd. [source] Trimethyl[3-methyl-1-(o -tolenesulfonyl)indol-2-ylmethyl]ammonium iodide and benzyl[3-bromo-1-(phenylsulfonyl)indol-2-ylmethyl]tolylamineACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2002P. R. Seshadri The title compounds, C20H25N2O2S+·I,, (I), and C29H25BrN2O2S, (II), respectively, both crystallize in space group P. The pyrrole ring subtends an angle with the sulfonyl group of 33.6° in (I) and 21.5° in (II). The phenyl ring of the sulfonyl substituent makes a dihedral angle with the best plane of the indole moiety of 81.6° in (I) and 67.2° in (II). The lengthening or shortening of the C,N bond distances in both compounds is due to the electron-withdrawing character of the phenylsulfonyl group. The S atoms are in distorted tetrahedral configurations. The molecular structures are stabilized by C,H,O and C,H,I interactions in (I), and by C,H,O and C,H,N interactions in (II). [source] | ||||||||||