Academic literature on the topic '4-dithiane'

δ-Valerolactone (3), on treatment with tris(methylthio)methyllithium (7) followed by weakly acidic aqueous work-up, gave a tautomeric mixture of 1, 1-bis(methylthio)-6-hydroxy-2-hexanone (8a) and tetrahydro-2-bis(methylthio)methyl-2-pyranol (8b). Under analogous conditions 3 reacted with tris(phenylthio)methyllithium (10) to form tetrahydro-3-(phenylthiocarbonyl)-2-pyranone (11). With 2-(methylthio)-1,3-dithian-2-yllithium (16) it gave a tautomeric mixture of 2-(5-hydroxy-1-oxopentyl)-2-(methylthio)-1,3-dithiane (17a) and 2-(tetrahydro-2-hydroxy-2-pyranyl)-2-(methylthio)-1,3-dithiane (17b). Treatment of 17 with methanol in the presence of acidic ion-exchange resin gave a mixture of 2-(5,6-dihydro-3-(methylthio)-2(4H)-pyranyl)-1,3-dithiane (20), 2-(tetrahydro-2-methoxy-2-pyranyl)-1,3-dithiane (21), and 2-(tetrahydro-2-methoxy-4-(methylthio)-2-pyranyl)-1,3-dithiane (22). Similar treatment of 20 gave a mixture of 20, 21, and 22. Compound 21 was synthesized independently by similar treatment of 2-(tetrahydro-2-hydroxy-2-pyranyl)-1,3-dithiane (23). The origins of the anomalous products are discussed briefly. It is concluded that because of these anomalies the preparation of tetrahydro-2-hydroxypyran-2-carboxylic acid acetals and related glycosides via trithio-orthoformate derivatives can encounter difficulties, although dithioacetals may serve this purpose. Key words: 1,3-dithianes, α-hydroxy acids,δ-lactones, trithio-orthoformates.

A model calix[4]arene-based rosette carrying two alternating photocleavable dithianyl-hydroxy-methyl moieties and two benzophenonecarboxylates was synthesized and shown to be capable of photoinduced fragmentation, with efficiency comparable to that of the externally sensitized parent dithiane–benzaldehyde adducts.Key words: photoinduced electron transfer, photofragmentation, calixarene, dithiane–carbonyl adducts.

The synthesis of 2-(4-methoxyphenylseleno)-1,3-dithiane 3 and 2-(4-trifluoromethylphenylseleno)-1,3-dithiane 5 from 2-chloro-1,3-dithiane 1 and the corresponding sodium arylselenolates is described. Nuclear magnetic resonance spectroscopic investigation of the products indicates that the compounds exist predominantly in a conformation in which the arylseleno moiety adopts an axial orientation. X-ray crystallographic investigation indicates that the 1,3-dithiane ring exists in the chair conformation with the arylseleno moiety in the axial orientation. Compound 3 is orthorhombic, space group P212121 with a = 5.449(2) Å, b = 9.217(2) Å, c = 24.860(3) Å, V = 1248.5 Å3, Z = 4. The structure was refined to R = 0.038 for 689 reflections with I > 2.3σ(I). Compound 5 is monoclinic, space group C2/c, with a = 28.628(7) Å, b = 5.246(2) Å, c = 21.342(5) Å, β = 121.12(1)°, V = 2743.8 Å3, Z = 8. Its structure refined to R = 0.064 for 966 reflections with I > 2.3σ(I).

The title compound, [SnBr4(C4H8S2)] {systematic name:catena-poly[[tetrabromidotin(IV)]-μ-1,4-dithiane-κ2S:S′]}, represents the first 1,4-dithiane complex with tin as coordination centre. The asymmetric unit consist of half a formula unit with the tin(IV) atom at the centre of symmetry at 0,0,1/2 (Wyckoff symbolb) and a centrosymmetric 1,4-dithiane molecule with the centre of symmetry in 1/2,0,1 (Wyckoff symbolc). The tin(IV) atom is coordinated in a distorted octahedral manner by the four bromine atoms and two sulfur atoms of two 1,4-dithiane molecules in atrans-position. Sn—Br [mean value: 2.561 (5) Å] and Sn—S distances [2.6546 (6) Å] are in the typical range for octahedrally coordinated tin(IV) atoms and the dithiane molecule adopts a chair conformation. The one-dimensional polymeric chains propagate along the [101] direction with weak intermolecular Br...Br [3.5724 (4) Å] between parallel chains and weak Br...H interactions [2.944–2.993 Å] within the chains.

The reaction of antimony(III) chloride with 1,4-dithiane (1,4-dt) in the ionic liquid [BMIM]Cl ([BMIM]Cl: 1-butyl-4-methylimidazolium chloride) with an excess of the Lewis acid AlCl3 results in the formation of a ligand-stabilized stibenium cation [SbCl2]+. 1,4-Dithiane simultaneously serves as a chelating η2-ligand, exhibiting a boat-like conformation, as well as a bridging μ2-ligand, exhibiting a chair-like conformation, with Sb3+ as the coordinating cation. Due to the bridging 1,4-dithiane ligands, a chain-like structural building unit 1∞[SbCl2(η2-1,4-dt)1/1(μ2-1,4-dt)2/2]+ is formed.

The use of cadmium chloride to control the regioselectivity of vinylogous anions upon condensation with aldehydes is described. Addition occurred preferentially at the γ position with substituted crotonates and 2-ethylidene-1,3-dithiane (6). Experiments demonstrated that this selectivity arose as a consequence of isomerization of the initially formed kinetic α product to the thermodynamic γ product (e.g., 2 to 4). The optimum results were achieved with 2 equivalents of cadmium chloride and quenching at 0 °C. Key words: vinylogous anions, cadmium, condensation, dithiane.

A facile synthesis of 4-hydroxy-3-arylthiazolidine-2-thiones through novel domino reactions of aryl isothiocyanates and 1,4-dithiane-2,5-diol under solvent- and catalyst-free microwave irradiation is reported.

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SuperfÃcie de ouro modificada com as espÃcies 1,4-ditiano (1,4-dt) e 4- mercaptopiridina (pyS), foram estudadas neste trabalho. Para a realizaÃÃo desse estudo foram utilizadas as seguintes tÃcnicas eletroquÃmicas: polarizaÃÃo linear com eletrodo de disco rotatÃrio, voltametria cÃclica, voltametria de pulso diferencial, impedÃncia eletro-hidrodinÃmica e espectroscopia de impedÃncia eletroquÃmica. Outras tÃcnicas tambÃm deram suporte, tais como, microscopia de forÃa atÃmica (MFA), microscopia de superfÃcie por tunelamento (MST), espectroscopia RAMAN e microbalanÃa de quartzo (MBQ). Para as superfÃcies modificadas com a molÃcula 1,4-dt, foi observado a diminuiÃÃo do processo redox [Fe(CN)6]3-/4- com o aumento do tempo de imersÃo do eletrodo de ouro na soluÃÃo modificadora. Estes resultados sugerem que taxa de recobrimento da superfÃcie de ouro, com esta espÃcie, aumenta com o tempo de modificaÃÃo. Os resultados de impedÃncia eletro-hidrodinÃmica juntamente com as micrografias MFA e MST revelam que esta superfÃcie està parcialmente bloqueada apresentando defeitos sobre o filme formado. Os resultados de espectroscopia RAMAN sugerem que esses defeitos podem ser resultantes da adsorÃÃo das conformaÃÃes diferenciadas na forma de âcadeiraâ e âbarcoâ da molÃcula 1,4 dt. Por outro lado, os resultados eletroquÃmicos com as superfÃcies modificadas com a espÃcie pyS indicam um aumento do processo de transferÃncia de carga com o aumento do tempo de imersÃo do eletrodo de ouro na soluÃÃo modificadora. Este resultado sugere a perda do poder de cobertura para a superfÃcie de ouro modificada com esta espÃcie. Os resultados de MFA reforÃam os resultados anteriores para esta espÃcie demonstrando que esta superfÃcie apresenta maiores quantidade de defeitos para tempos mais longos de modificaÃÃo. As curvas de variaÃÃo de freqÃÃncia (ΔF) versus tempo de modificaÃÃo indicam um aumento de massa na superfÃcie de ouro modificada com a espÃcie 1,4-dt, enquanto que para a espÃcie pyS observa-se um processo de desorÃÃo, confirmando qualitativamente os resultados obtidos anteriores para estas duas molÃculas.
Modified gold surface with organosulfur species, 1,4-dithiane (1,4-dt) and 4- mercaptopyridine (pyS), was studied in this work. The study was carried out using the following electrochemical techniques: linear polarization with rotate disk electrode, cyclic voltammetry, differential pulse voltammetry, electrohydrodynamic impedance and electrochemical impedance spectroscopy. Other techniques also gave support, such as, atomic force microscopy (AFM), Scanning tunneling microscopy (STM), RAMAN spectroscopy and quartz crystal microbalance (QCM). For the modified gold surface with the 1,4-dt, it was observed the decrease of the redox-active [Fe(CN)6]3- species with the increase of the immersion time of the gold electrode in the modifier solution. These results suggest that the fractional coverage increases with the modification time. The electrohydrodynamic impedance results together with the MFA and MST results suggest that this surface is partially blocked presenting defects on the formed film. The RAMAN spectra suggest that those defects can be resulting of the adsorption of the different configuration of the modifier molecules (1,4-dt) on the surface ("trans" and "gauche"). The electrochemical results about the modified gold surfaces with the molecule pyS indicate an increase of the electron transfer process with the increase of the immersion time, which suggests the loss of the covering power on the modified gold surface with this species. The AFM results agree the previous results demonstrating that this surface presents larger amount of defects for longer modification times. The frequency curves variation (ΔF) versus the immersion time indicate a mass increase on the modified gold surface with the species 1,4-dt and a process desorption for the species pyS confirming the results obtained previously.

Nos travaux s'inscrivent dans le domaine de la chimie des cétohexoses et en particulier de deux d'entre eux : le D-fructose et le D-psicose. En vue de l'évaluation des potentialités biologiques de ces oses, nous avons d'abord étudié les voies'd'accès à des nucléosides dérivés du D-fructofuranose puis la synthèse de composés aminés issus de cet ose et du D-psicofuranose. Cette approche nous a amené à mettre au point la préparation d'un dérivé du D-psicofuranose comportant une différenciation au niveau de ses deux hydroxyméthyles. Ce composé devrait permettre de résoudre certains problèmes synthétiques inhérents à la chimie des cétohexoses et qui n'avaient pas trouvé jusqu'ici de solution satisfaisante.

(–)-GB17 3 is one of the Galbulimima alkaloids, a family that shows a wide range of interesting physiological activity. Regan J. Thomson of Northwestern University devised (Angew. Chem. Int. Ed. 2012, 51, 2481) a convergent assembly of 3, a key step of which was the intramolecular Michael cyclization of 1 to 2. The hydroxy aldehyde 6 was prepared by alkylation of the dithiane 4 with 5, followed by hydrolysis. The preparation of 9, by condensation of 8 with 7 followed by hydrogenation and protection, had been reported by Lhommet. Condensation of 9 with the linchpin reagent 10 gave an intermediate keto phosphonate, which was combined with 6 to give, after oxidation, the aldehyde 1. Two new stereogenic centers are created in the course of the cyclization of 1. The authors found that the TFA salt 11 of the Hayashi catalyst delivered 2 with high diastereocontrol. Control experiments showed that the buttressing effect of the dithiane was required for the cyclization. The authors then explored the next intramolecular Michael cyclization of 13 to 14. In this cyclization, the stereogenic center at 6 is in jeopardy by elimination and readdition. Cyclization of the trans unsaturated ester led to the wrong diastereomer of 14, but cyclization of the cis ester 13, prepared by the Still-Gennari protocol, cleanly gave the desired diastereomer. The reaction worked best with the free amine. Under the conditions of the reaction the Michael addition product spontaneously cyclized to the lactam 14. The ketone of 14 was selectively enolized, then converted to its enol triflate, which under Pd-mediated reduction gave the alkene 15. Alkylation of 15 with 16 predominantly gave the diene 18. Hydrolysis of the dithiane to the ketone followed by reduction gave mainly the desired equatorial alcohol, which was cleaved oxidatively to (–)-GB17 3. Although there have been many isolated reports of the utility of intramolecular Michael addition as a synthetic method, there has been little systematic investigation. The optimization studies that are the heart of this work are a welcome addition.

Stephen G. DiMagno of the University of Nebraska developed (Chem. Eur. J. 2015, 21, 6394) a protocol for the clean monoiodination of 1 to 2. The bromomethylation (or chloromethylation, with HCl) of a benzene derivative is straightforward with formal­dehyde and HBr. Naofumi Tsukada of Shizuoka University designed (Organometallics 2015, 34, 1191) a Cu catalyst that mediated the coupling of an alkyne with the benzyl bromide so produced, effecting net propargylation of 3 with 4 to give 5. Triazenes such as 7, versatile intermediates for organic synthesis, are usually prepared by diazotization of the corresponding aniline. Kay Severin of the Ecole Polytechnique Fédérale de Lausanne established (Angew. Chem. Int. Ed. 2015, 54, 302) an alternative route from the aryl Grignard reagent 6. Ping Lu and Yanguang Wang of Zhejiang University showed (Chem. Commun. 2015, 51, 2840) that dimethylformamide could serve as the carbon source for the conversion of 8 to the nitrile 9. Junha Jeon of the University of Texas at Arlington effected (J. Org. Chem. 2015, 80, 4661; Chem. Commun. 2015, 51, 3778) the reductive ortho silylation of 10 to give 11. Vladimir Gevorgyan of the University of Illinois at Chicago found (Angew. Chem. Int. Ed. 2015, 54, 2255) that the phenol derivative 12 could be ortho carboxylated, leading to 13. Lutz Ackermann of the Georg-August-Universität Göttingen, starting (Chem. Eur. J. 2015, 21, 8812) with the designed amide 14, effected ortho metala­tion followed by coupling, to give the methylated product 15. Tetsuya Satoh and Masahiro Miura of Osaka University used (Org. Lett. 2015, 17, 704) the dithiane of 16 to direct ortho metalation. Coupling with acrylate followed by reductive desulfu­rization led to the ester 17. Jin-Quan Yu of Scripps/La Jolla designed (Angew. Chem. Int. Ed. 2015, 54, 888) the phenylacetamide 18 to direct selective meta metalation, leading to the unsat­urated aldehyde 19. In an extension of the Catellani protocol, Guangbin Dong of the University of Texas prepared (J. Am. Chem. Soc. 2015, 137, 5887) the biphenyl 21 by net meta metalation of the benzylamine 20. Several methods for the de novo assembly of benzene derivatives have recently been put forward. Rajeev S. Menon of the Indian Institute of Chemical Technology condensed (Org. Lett. 2015, 17, 1449) the unsaturated aldehyde 22 with the sulfonyl ester 23 to give 24.

Shou-Fei Zhu of Nankai University developed (Angew. Chem. Int. Ed. 2014, 53, 13188) an iron catalyst that effected the enantioselective cyclization of 1 to 2. Bypassing diazo precursors, Junliang Zhang of East China Normal University used (Angew. Chem. Int. Ed. 2014, 53, 13751) a gold catalyst to cyclize 3 to 4. Taking advantage of energy transfer from a catalytic Ir complex, Chuo Chen of University of Texas Southwestern carried out (Science 2014, 346, 219) intramolec­ular 2+2 cycloaddition of 5, leading, after dithiane formation, to the cyclobutane 6. Intramolecular ketene cycloaddition has been limited in scope. Liming Zhang of the University of California Santa Barbara found (Angew. Chem. Int. Ed. 2014, 53, 9572) that intramolecular oxidation of an intermediate Ru vinylidene led to a species that cyclized to the cyclobutanone 8. James D. White of Oregon State University devised (J. Am. Chem. Soc. 2014, 136, 13578) an iron catalyst that mediated the enantioselective Conia-ene cyclization of 9 to 10. Xiaoming Feng of Sichuan University observed (Angew. Chem. Int. Ed. 2014, 53, 11579) that the Ni-catalyzed Claisen rearrangement of 11 proceeded with high diastereo- and enantiocontrol. The relative configuration of the product 12 was not reported. Robert H. Grubbs of Caltech showed (J. Am. Chem. Soc. 2014, 136, 13029) that ring opening cross metathesis of 13 with 14 delivered the Z product 15. Mn(III) cyclization has in the past required a stoichiometric amount of inorganic oxidant. Sangho Koo of Myong Ji University found (Adv. Synth. Catal. 2014, 356, 3059) that by adding a Co co- catalyst, air could serve as the stoichiometric oxidant. Indeed, 16 could be cyclized to 17 using inexpensive Mn(II). Matthias Beller of the Leibniz-Institüt für Katalyse prepared (Angew. Chem. Int. Ed. 2014, 53, 13049) the cyclohexene 20 by coupling the racemic alcohol 18 with the amine 19. Paultheo von Zezschwitz of Philipps-Universität Marburg added (Chem. Commun. 2014, 50, 15897) diethyl zinc in a conjugate sense to 21, then reduced the product to give 22. Depending on the reduction method, either diastereomer of the product could be made dominant. Nuno Maulide of the University of Vienna dis­placed (Angew. Chem. Int. Ed. 2014, 53, 7068) the racemic chloride 23 with diethyl zinc to give 24 as a single diastereomer.

Dithianes such as 1 are readily prepared, from the corresponding ketone or by alkyl­ation. Masayuki Kirihara of the Shizuoka Institute of Science and Technology devel­oped (Tetrahedron Lett. 2013, 54, 5477) an oxidative method for the deprotection of 1 to 2. Konrad Tiefenbacher of the Technische Universität München devised (J. Am. Chem. Soc. 2013, 135, 16213) a hexameric resorcinarene capsule that selectively catalyzed the hydrolysis of the smaller acetal 3 to 4 in the presence of a longer chain acetal. David J. Gorin of Smith College reported (J. Org. Chem. 2013, 78, 11606) the methylation of an acid 5 to 6 using dimethyl carbonate as the donor. Two peroxide-based methods (J. Org. Chem. 2013, 78, 9898; Org. Lett. 2013, 15, 3326) for carboxylic acid methylation (not illustrated) were also recently described. Hisashi Yamamoto of the University of Chicago showed (Angew. Chem. Int. Ed. 2013, 52, 7198) that the “supersilyl” ester 8, prepared from 7, was stable enough to be deprotonated and alkyl­ated, but was easily removed. Michal Szostak and David J. Procter of the University of Manchester uncovered (Angew. Chem. Int. Ed. 2013, 52, 7237) the remarkable cleavage of a C–N bond in an amide 9, leading to the secondary amide 10. This could offer an alternative strategy for difficult-to-hydrolyze amides. Richard B. Silverman of Northwestern University described (J. Org. Chem. 2013, 78, 10931) improved protocols for the formation and removal of the N-protecting 2,5-dimethylpyrrole 11 to give 12. Huanfeng Jiang of the South China University of Technology showed (Chem. Commun. 2013, 49, 6102) that an arenesulfonamide 14 can be prepared by oxidation of the corresponding sodium arenesulfinate 13. Douglas A. Klumpp of Northern Illinois University prepared (Tetrahedron Lett. 2013, 54, 5945) sul­fonamides (not illustrated) by combining a sulfonyl fluoride with a silyl amine. K. Rajender Reddy of the Indian Institute of Chemical Technology developed (Chem. Commun. 2013, 49, 6686) a new route to a urea 17, by oxidative coupling of an amine 15 with a formamide 16.