- Ring enlargement and sulfur-transfer processes in SiO2-catalyzed reactions of thiocarbonyl compounds with optically active oxiranes
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The reactions of 1,3-dioxolane-2-thione (3) with (S)-2-methyloxirane ((S)-1) and with (R)-2-phenyloxirane ((R)-2) in the presence of SiO2 in anhydrous dichloroalkanes led to the optically active spirocyclic 1,3-oxathiolanes 8 with Me at C(7) and 9 with Ph at C(8), respectively (Schemes 2 and 3). The analogous reaction of 1,3-dimethylimidazolidine-2-thione (4a) with (R)-2 yielded stereoselectively (S)-2-phenylthiirane ((S)-10) in 83% yield and 97% ee together with 1,3-dimethylimidazolidin-2-one (11a). In the cases of 3-phenyloxazolidine-2-thione (4b) and 3-phenylthiazolidine-2-thione (4c), the reaction with (RS)-2 yielded the racemic thiirane (RS)-10, and the corresponding carbonyl compounds 11b and 11c (Scheme 4 and Table 1). The analogous reaction of 4a with 1,2-epoxycyclohexane (=7-oxabicyclo[4.1.0]heptane; 7) afforded thiirane 12 and the corresponding carbonyl compound 11a (Scheme 5). On the other hand, the BF3-catalyzed reaction of imidazolidine-2-thione (5) with (RS)-2 yielded the imidazolidine-2-thione derivative 13 almost quantitatively (Scheme 6). In a refluxing xylene solution, 1,3-diacetylimidazolidine-2-thione (6) and (RS)-2 reacted to give two imidazolidine-2-thione derivatives, 13 and 14 (Scheme 7). The structures of 13 and 14 were established by X-ray crystallography (Fig.).
- Malaschichin, Sergej,Fu, Changchun,Linden, Anthony,Heimgartner, Heinz
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- Dichloro (5,10,15,20-tetraphenylporphyrin) phosphorus(V) chloride as a new catalyst for conversion of 1,2-epoxyethanes to 2-hydroxyethyl thiocyanates with ammonium thiocyanate
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A convenient and efficient procedure for the cleavage of the oxirane rings with ammonium thiocyanate in the presence of phosphorus(V)tetraphenylporphyrin is described. The ring-opening of 1,2-epoxyethanes is found to proceed regioselectively under mild reaction conditions. Thus, several 2-hydroxyethyl thiocyanates, useful intermediates toward biologically active molecules, are easily obtained in very good yields.
- Sharghi, Hashem,Nejad, Alireza Hassani
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- Metalloporphyrins as new catalysts in the mild, efficient and regioselective conversion of epoxides to β-hydroxy thiocyanates with NH4SCN
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The regioselective cleavage of 1,2-epoxyethanes to 2-hydroxyethyl thiocyanates with ammonium thiocyanates in the presence of some metalloporphyrins has been studied. The epoxides were subject to cleavage by NH4SCN in the presence of these catal
- Sharghi, Hashem,Nejad, Alireza Hassani,Nasseri, Mohammad Ali
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Read Online
- ZnFe2O4 nanoparticles: A green and recyclable magnetic catalyst for fast and regioselective conversion of epoxides to vicinal hydroxythiocyanates using NH4SCN under solvent-free conditions
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ZnFe2O4 nanoparticles were synthesized and used as recyclable magnetic catalyst in the solvent-free conversion of different epoxides to vicinal hydroxythiocyanates with NH4SCN at room temperature. The reactions were carrie
- Eisavi, Ronak,Alifam, Somayieh
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p. 211 - 217
(2017/11/10)
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- A Highly Regioselective Palladium-Catalyzed O,S Rearrangement of Cyclic Thiocarbonates
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This work describes an operationally simple catalytic synthesis of cyclic S-thiocarbonates with predictable regioselectivity in good yields. The reaction utilizes substrates derived from ubiquitous 1,2-diols in an atom economical intramolecular rearrangement, catalysed by an inexpensive and simple catalyst–ligand system. A crystal structure is presented that clearly confirms the regioselectivity of the reaction.
- Mahy, William,Cabezas-Hayes, Sinéad,Kociok-K?hn, Gabriele,Frost, Christopher G.
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p. 6441 - 6444
(2017/11/13)
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- Green synthesis of thiiranes from oxiranes under solvent- and catalyst-free conditions
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A simple and efficient method for the conversion of oxiranes to thiiranes using ammonium thiocyanate (NH4SCN) under solvent- and catalyst-free conditions is described. These conditions enable clean and fast conversion of oxiranes to the corresponding thiirane.
- Akhlaghinia, Batool,Rahimizadeh, Mohammad,Eshghi, Hosein,Zhaleh, Sara,Rezazadeh, Soodabeh
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experimental part
p. 351 - 361
(2012/08/27)
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- Fast, efficient and regioselective conversion of epoxides to β-hydroxy thiocyanates with NH4SCN/zeolite molecular sieve 4 A under solvent-free conditions
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Solvent-free conversion of various epoxides to their corresponding β-hydroxy thiocyanates was carried out successfully with NH 4SCN/zeolite molecular sieve 4 A system at room temperature. The reactions were completed within 2 - 7 min to give th
- Eisavi, Ronak,Zeynizadeh, Behzad,Baradarani, Mohammad Mehdi
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scheme or table
p. 630 - 634
(2011/12/03)
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- A facile and efficient one-pot synthesis of thiirans by the reaction of benzoxazolyl β-ketosulfides with NaBH4/NaOH
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Convenient and efficient procedures for thiirans have been developed via a one-pot reaction of benzoxazolyl β-ketosulfides with NaBH4 and NaOH in MeOH and THF. The reaction is considered to proceed via the spiro intermediate by the ipso-additio
- Yamada, Nobuhiko,Mizuochi, Masayoshi,Takeda, Masahiro,Kawaguchi, Hiroyuki,Morita, Hiroyuki
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p. 1166 - 1168
(2008/09/18)
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- Reaction between epoxides and carbon disulfide under hydrotalcite catalysis: Eco compatible synthesis of cyclic dithiocarbonates
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Cyclic dithiocarbonates were prepared in good yield and excellent selectivity through an environmental acceptable methodology involving the reaction of substituted epoxides with carbon disulfide under hydrotalcite catalysis. The catalyst can be recovered by filtration and reused several times. Georg Thieme Verlag Stuttgart.
- Maggi, Raimondo,Malmassari, Clara,Oro, Chiara,Pela, Roberto,Sartori, Giovanni,Soldi, Laura
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- Thermolysis of β-hydroxysulfides bearing several heteroaromatics
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Thermolyses of β-hydroxysulfides 2, bearing groups, such as 2-benzothiazolyl and 4-(4-methyl)-4H-1,2,4-triazolyl groups, were studied and found to afford the corresponding substituted styrenes 5 and hydroxy heteroaromatics in good yields, respectively. The product distribution change in the course of the thermolysis of 2a was also studied. The olefin products 5a were considered to be formed by the thermal desulfurization of the corresponding thiiranes 4a initially formed via the five-membered spiro intermediate 6a.
- Yamada, Nobuhiko,Mizuochi, Masayoshi,Morita, Hiroyuki
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p. 3408 - 3414
(2007/10/03)
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- Conversion of epoxides into 2-hydroxyethyl thiocyanates with NH 4SCN in the presense of 2,6-BIS[2-(O-amino phenoxy)methyl]-4-bromo-1- methoxybenzene (BABMB) as catalyst
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A convenient and efficient procedure for the ring-opening of 1,2-epoxyethanes with ammonium thiocyanate in the presence of 2,6-bis[2-(o-aminophenoxy)methyl]-4-bromo-1-methoxybenzene (BABMB) is described. In this study, a reagent and conditions have been discovered with which the individual 2-hydroxyethyl thiocyanates can be synthesized in high yield and with more than 90% regioselectivity. Thus, several 2-hydroxyethyl thiocyanates, useful intermediates toward biological-active molecules, are easily obtained in very good yields.
- Niknam, Khodabakhsh
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p. 499 - 506
(2007/10/03)
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- Thermal degradation processes in polysulfide copolymers investigated by direct pyrolysis mass spectrometry and flash pyrolysis - Gas chromatography/mass spectrometry
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This is the first report on the analysis of random block polysulfide copolymers containing different amounts of repeating units in the copolymer backbone, which has been studied by direct pyrolysis mass spectrometry (DPMS) and by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The homopolymers such as poly(ethylene sulfide) (PES), poly(styrene sulfide) (PSS), and two random copolymers, viz., poly(ethylene sulfidex-co-styrene sulfidey) [copolymer I (x = y = 0.5) and copolymer II (x = 0.74, y = 0.26)] were investigated by both DPMS and Py-GC/MS (except copolymer II) techniques. In the case of copolymer I, the thermal degradation products of SE1, SE2, S2, and S2E (S = styrene sulfide, E = ethylene sulfide) were detected in DPMS, whereas the formation of SE1 and SE2 were observed by Py-GC/MS technique. However, for copolymer II, SE3 was also found along with SE1, SE2, S2, and S2E in DPMS. The formation of additional product (SE3) observed in copolymer II could be due to an increase in the block length formed during copolymerization. Further, a comparative study on thermal degradation of PES, poly(ethylene disulfide) (PEDS), and poly(ethylene tetrasulfide) (PETS) were investigated by Py-GC/MS. The pyrolysis products detected by both DPMS and Py-GC/MS indicates that the thermal decomposition of these polymers yield cyclic sulfides through an intramolecular exchange or by backbiting processes. The linear products with thiol and vinyl groups were also observed by Py-GC/MS along with the cyclic products via carbon hydrogen transfer reaction.
- Sundarrajan,Surianarayanan,Srinivasan,Kishore
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p. 3331 - 3337
(2007/10/03)
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- An expeditious one-pot synthesis of thiiranes from α-halo ketones in solvent-free conditions using microwaves
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Thiiranes are obtained in excellent yields and with high diastereoselectivity upon microwave irradiation of a mixture of α-haloketones, O,O-diethyl hydrogen phosphorodithioate and alumina-supported sodium borohydride in solvent-free conditions.
- Yadav, Lal Dhar S.,Kapoor, Ritu
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p. 2344 - 2346
(2007/10/03)
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- N-bis(methylthio)methylene derivatives. VII. Syntheses and reactions of synthetic equivalents of new 1,3-dipolar reagents using N- bis(methylthio)methylene derivatives
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N-Cyano- or N-(p-toluenesulfonyl)-N'-(trimethylsilylmethyl)-S- methylisothioureas (3,4), readily prepared by reactions of S,S'-dimethyl N- cyano- (1a) and S,S'-dimethyl N-(p-toluenesulfonyl)- (1b) carbonimidodithioates with trimethylsilylmethylamine (2a), followed by N- alkylation, have been found to provide synthetic equivalents of iminoazomethine ylide. Treatment of these compounds with cesium fluoride in the presence of reactive heterodipolarophiles such as carbonyl compounds afforded 1,3-dipolar cycloadducts, 4,5-dihydro-2-iminooxazoles and 4,5- dihydro-2-iminothiazoles, via the 1,3-elimination of (methylthio)trimethylsilane. S-Methyl-S'-trimethylsilylmethyl N-cyano- (5a) and N-(p-toluene-sulfonyl)- (5b) carbonimidodithioates, also readily prepared from the corresponding 1a and 1b with (mercaptomethyl)trimethylsilane (2b), were used as new reagents for introducing a thioformaldehyde unit at a carbonyl carbon. Reactions of these compounds with aldehydes in the presence of cesium fluoride afforded thiiranes via the 1,3-dipolar cycloaddition of iminothiocarbonyl ylide to the C=O double bond. Reactions of 5 with dimethyl fumarate and maleate in the presence of cesium fluoride in acetonitrile gave 1,3-dipolar cycloadducts, dimethyl 2-(N-(p- toluenesulfonyl)imino)tetrahydrothiophene-3,4-dicarboxylates.
- Tominaga,Ogata,Ueda,Kohra,Hosomi
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p. 1425 - 1434
(2007/10/03)
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- PREPARATION OF NEW THIOCARBANION SPECIES BEARING THIAZOLINYL AND BENZOTHIAZOLYL GROUPS AND REACTIONS WITH CARBONYL COMPOUNDS
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2-Trimethylsilylmethylthiothiazoline (1) reacted with aromatic aldehydes in the presence of cesium fluoride or tris(dimethylamino)sulfur(trimethylsilyl)difluoride (TASF) to give 2-heteroarylthioethanol (4) or thiiran (5) derivatives in good yields.The rea
- Kohra, Shinya,Ueda, Hiroshi,Tominaga, Yoshinori
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p. 2673 - 2676
(2007/10/02)
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- New synthesis of thiiranes by fluoride ion-promoted reaction of S-methyl-S'-trimethylsilylmethyl N-(p-toluenesulfonyl)dithioiminocarbonate and 2-(trimethylsilylmethylthio)thiazoline with aldehydes
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The title compounds, readily prepared by the reaction of the corresponding S-methyl N-(p-toluene-sulfonyl)dithioiminocarbonate and 2-mercaptothiazoline with (chloromethyl)trimethylsilane in the presence of a base, were used as a new reagents for the intro
- Tominaga,Ueda,Ogata,Kohra,Hojo,Ohkuma,Tomita,Hosomi
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- Selective Conversion of 2-Mercaptoalkanols to Thiirans with Orthocarbonates
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Tetraalkyl orthocarbonates 1 were demonstrated to serve as potent cyclodehydrating agents for 2-mercaptoalkanols 2 to give the corresponding thiirans in good yields in acid-catalyzed reactions in aprotic solvents.Effect of catalysts, solvents, and alkyl substituents of 1 were examined.Activity of the acid catalysts depended on their acidity (pKa), and the strong Lewis acid BF3*OEt2 also had high catalytic activity.Effects of solvents and alkyl substituents of 1 were little observed.
- Takata, Toshizaku,Endo, Takeshi
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p. 1818 - 1820
(2007/10/02)
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- THE CHEMISTRY OF α,ω-MERCAPTOALCOHOLS IN THE PRESENCE OF DIETHOXYTRIPHENYLPHOSPHORANE. TEMEPERATURE DEPENDENCE OF CYCLODEHYDRATIONS AND S-ETHYLATIONS
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Diethoxytriphenylphosphorane (DTPP) is easily prepared by oxidative addition of triphenylphosphine with diethyl peroxide.DTPP converts a variety of mercaptoalcohols to cyclic sulfides as well as hydroxythioethers.The temperature dependence (+25 --> -25 deg C) of the product distribution has synthetic petential.
- Robinson, Philip L.,Kelly, Jeffery W.,Slayton, A. Evans
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- DIOXYPHOSPHORANES, AN EMERGING CLASS OF VERSATILE REAGENTS FOR ORGANIC SYNTHESIS
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Several ?-dioxyphosphoranes have been prepared and their structural characterizations using NMR techniques support the trigonal bipyramidal conformer as the most stable for the acyclic phosphoranes.Their utility in smooth conversions of hydroxylated substrates to the corresponding X-heterocycles is documented.
- Kelly, Jeffery W.,Robinson, Philip L.,Evans, Slayton A.
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p. 147 - 150
(2007/10/02)
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- Pesticidal compositions containing phosphoric esters and divalent sulphur compounds
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Pesticidal composition comprising: a pesticidal, phosphoric ester the molecule of which has at least one alkyl group of 1 to 3 carbon atoms, 0.05 to 10% of an agent stabilizing the said ester against decomposition by protonisation, together with adjuvants characterized in that the stabilizing agent comprises at least one sulphur compound containing per molecule at least one divalent sulphur atom of which one valence is bonded to an atom chosen from sulphur, carbon, nitrogen, hydrogen, and metals capable of giving a salt, the other valence being bonded to an atom chosen from hydrogen, the carbon atom already noted, a second carbon atom, the nitrogen atom already noted, a second nitrogen atom, the metal atom already noted in the case of a metal of valence greater than one, a second atom of metal and oxygen when the first valence is not attached to an atom of hydrogen, the proportion of sulphur calculated with reference to the weight of the sulphur compound being between 5 and 99%. Process for stabilizing a phosphoric ester of which the molecule possesses at least one alkyl group containing 1 to 3 carbon atoms characterized in that there is added to the phosphoric ester or to a mixture which contains it, 0.05 to 10% calculated on the weight of the phosphoric acid ester of an agent capable of stabilizing the said phosphoric ester against protonisation and comprising at least one sulphur compound such as that defined thereupon.
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