- Synthesis of common-sized heterocyclic compounds by intramolecular cyclization over halide cluster catalysts
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Five- to seven-membered common-sized heterocyclic compounds containing an oxygen, sulfur, or nitrogen were synthesized by the intramolecular condensation of α,ω-hydroxy, mercapto, or amino alkanes, respectively, over halide cluster complexes as a thermally stable molecular solid weak acid catalyst in the gas phase at temperatures ≥150 °C. From ω- mercapto and ω-amino alcohols, cyclic sulfides and amines were obtained, respectively. These unimolecular reactions are thermodynamically and kinetically favored.
- Nagashima, Sayoko,Sasaki, Tomoaki,Kamiguchi, Satoshi,Chihara, Teiji
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supporting information
p. 764 - 766
(2015/06/22)
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- Synthesis of 3,6-diaryl-1,4,5-thiadiazepines from substituted 2-thiocyano acetophenone and investigation of reaction mechanism
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In this work, we have studied the reaction of substituted 2-thiocyanoacetophenone and hydrazine hydrate as a novel and simple pathway for the preparation of the substituted 1,4,5-thiodiazepine ring system. The mechanism of this reaction revealed that in the initial step condensation of hydrazine with carbonyl groups of substituted 2-thiocyanoacetophenons 2a-2f gives the corresponding substituted aromatic dithiocyano azide intermediates which in turn undergo cyclization to1,4,5-thiadiazepines in the presence of hydrazine. This cyclization is a novel method for the preparation of sulfide bond from the reaction of hydrazine and a dithiocyano intermediate. An account of the reaction mechanism is given.
- Rahimizadeh,Feizyzadeh,Bakavoli,Eshghi
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p. 276 - 283
(2013/08/26)
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- A kinetic investigation, supported by theoretical calculations, of steric and ring strain effects on the oxidation of sulfides and sulfoxides by dimethyldioxirane in acetone
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The oxidations of alkyl 4-nitrophenyl, and dialkyl, sulfides and sulfoxides by dimethyldioxirane in acetone occur by concerted mechanisms but the sulfides respond differently from the sulfoxides to variation in the alkyl group. The reactions of the sulfides are inhibited by the steric effects of alkyl groups and these predominate over their inductive effects. By contrast, the reactions of these limited sets of sulfoxides are insensitive to alkyl steric effects but there is an indication of steric acceleration when a broader set of sulfoxides is considered. This behaviour is rationalised in terms of the differences in dipolar charge and its solvation between the ground state and transition state for the two types of substrate. The oxidations of cyclic sulfides and sulfoxides also exhibit contrasting behaviour. The reactivity of the sulfides is insensitive to ring strain but is explicable in frontier orbital terms whereas that of the sulfoxides is partly dependent upon the change in ring strain between reactant and product on oxidation, a difference rationalised in terms of the relative positions of the transition states in the reaction coordinates of the two oxidations. The reactivity of 4-, 5- and 6-membered cyclic sulfoxides is also dependent on a ring-size related property of the transition state. Calculations at the B3-LYP/6-31G* level of density functional theory on both ground states and transition states, including simulation of solvation by acetone, strongly support the mechanistic conclusions reached in this and earlier work.
- Hanson, Peter,Hendrickx, Ramon A. A. J.,Lindsay Smith, John R.
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supporting information; experimental part
p. 65 - 84
(2011/01/07)
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- The macrocyclization reaction of terminal dibromoalkanes with sulfide on alumina. The use of a solid support as an alternative to the high dilution technique
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The reaction of a series of terminal dibromoalkanes with S-2 on Al2O3 has been examined. The use of a solid support for the macrocyclization represents a viable alternate procedure to the more traditional high dilution technique in solution. The cyclization also occur with thioacetamide on unactivated alumina.
- Tan,Pagni,Kabalka,Hillmeyer,Woosley
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p. 7709 - 7712
(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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- Heterocyclisation alkylante radicalaire par photolyse de sulfures ethyleniques. III. Photolyse de sulfures de butene-3 yle-1 et hexene-5 yle-1
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Photolysis of allyl but-3-en-1-yl sulfide (I) gives the thiolan 3 and the 3-allylthiolan 4 resulting from "forbidden" 5-endotrig cyclization.Photolysis of allyl hex-5-en-1-yl sulfide (III) gives, besides the mixture of six- and seven-membered non-alkylated heterocycles 10 and 11, exclusively the alkylated 2-(but-3-enyl) thian 12.These and other results confirm and generalize the mechanism proposed earlier for the photolytic cyclization of pent-4-enyl sulfides.Photolitic cleavage of unsaturated allyl or benzyl sulfides gives the unsaturated thiyl radical.The unsaturated radical undergoes an intramolecular reversible addition out of the cage.Then the more stable cyclized radical is trapped selectively by the allyl or benzyl radical.
- Bastien, Gerard,Surzur, Jean-Marie
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