- KOtBu-Catalyzed Michael Addition Reactions Under Mild and Solvent-Free Conditions
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Designed transition metal complexes predominantly catalyze Michael addition reactions. Inorganic and organic base-catalyzed Michael addition reactions have been reported. However, known base-catalyzed reactions suffer from the requirement of solvents, additives, high pressure and also side-reactions. Herein, we demonstrate a mild and environmentally friendly strategy of readily available KOtBu-catalyzed Michael addition reactions. This simple inorganic base efficiently catalyzes the Michael addition of underexplored acrylonitriles, esters and amides with (oxa-, aza-, and thia-) heteroatom nucleophiles. This catalytic process proceeds under solvent-free conditions and at room temperature. Notably, this protocol offers an easy operational procedure, broad substrate scope with excellent selectivity, reaction scalability and excellent TON (>9900). Preliminary mechanistic studies revealed that the reaction follows an ionic mechanism. Formal synthesis of promazine is demonstrated using this catalytic protocol.
- Thiyagarajan, Subramanian,Krishnakumar, Varadhan,Gunanathan, Chidambaram
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supporting information
p. 518 - 523
(2020/02/04)
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- TRIAZOLE-BASED READER MOLECULES AND METHODS FOR SYNTHESIZING AND USE THEREOF
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Triazole-based molecules, methods of making and using the same are provided. Triazole-based molecules may be used as reading molecules and incorporated into or operatively-linked with electrodes, for example, and used in recognition tunneling systems to i
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Paragraph 0056
(2017/01/02)
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- PHARMACEUTICAL USE OF 3-BENZYLSULFONYLPROPIONITRILE
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The present invention is directed to a pharmaceutical composition comprising a pharmaceutically acceptable carrier and 3-benzylsulfonylpropionitrile, or a pharmaceutically acceptable salt thereof. The present invention is directed to a method for treating
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- Dithiooxamide as an Effective Sulfur Surrogate for Odorless High-Yielding Carbon-Sulfur Bond Formation in Wet PEG200 as an Eco-Friendly, Safe, and Recoverable Solvent
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In this study, we have employed dithiooxamide, a solid, odorless, and commercially available compound, as a sulfur surrogate for the preparation of dialkyl sulfides from available alkyl halides in high yields. This sulfur transfer agent was also used for a copper-catalyzed high-yielding preparation of diaryl sulfides from their available aryl halides and for the preparation of thia-Michael adducts in high yields. All the reactions were performed under odorless conditions in wet PEG200 (PEG = polyethylene glycol), which is an eco-friendly, safe, and recoverable solvent. The protocols were easily applicable to large-scale operation.
- Firouzabadi, Habib,Iranpoor, Nasser,Gorginpour, Forough,Samadi, Arash
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supporting information
p. 2914 - 2920
(2015/05/04)
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- Visible light promoted thiol-ene reactions using titanium dioxide
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The radical addition of thiols to alkenes is reported under photoredox conditions, using visible light and TiO2 as a cheap and readily available photocatalyst.
- Bhat, Venugopal T.,Duspara, Petar A.,Seo, Sangwon,Abu Bakar, Nor Syazwani Binti,Greaney, Michael F.
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supporting information
p. 4383 - 4385
(2015/03/18)
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- An atom-economic and odorless thia-Michael addition in a deep eutectic solvent
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The first 100% atom-efficient and odorless protocol for carbon-sulfur bond formation in a deep eutectic solvent (DES) as both the reaction medium and catalyst is reported. The biodegradable and inexpensive DES provides an efficient and convenient ionic reaction medium for the thia-Michael addition with in situ generation of S-alkylisothiouronium salts in place of thiols without the urea by-product segment. This protocol offers several advantages including short reaction times, high yields, clean reactions, and inexpensive and commercially available starting materials.
- Azizi, Najmedin,Yadollahy, Zahra,Rahimzadeh-Oskooee, Amin
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p. 1722 - 1725
(2014/03/21)
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- Novel atom-economic reaction: Comprehensive utilization of S-alkylisothiouronium salt in the synthesis of thioethers and guanidinium salts
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A novel atom-economic three-component one-pot reaction of a primary amine, an S-alkylisothiouronium salt and a Michael receptor is reported, which affords a guanidinium salt and thioether simultaneously. The guanidine moiety is involved in catalyzing the conjugated Michael addition of the mercaptan. The reaction proceeds under ambient conditions using a non-toxic EtOH-H2O mixture as the solvent, and the two products can be very easily purified. Complete atom economy is achieved by fully utilizing the S-alkylisothiouronium salt and converting the previously wasted mercaptan by-product into the valuable thioether.
- Gao, Pengchao,Leng, Penglin,Sun, Qi,Wang, Xin,Ge, Zemei,Li, Runtao
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p. 17150 - 17155
(2013/09/24)
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- Mild hydrosulfenylation of Olefins under neutral conditions using a defined NHC-ligated iron-sulfur catalyst
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A defined NHC-Fe-S complex proved to be an efficient catalyst for the selective hydrosulfenylation of α,β-unsaturated ketones or vinylnitriles. A wide range of different aliphatic thiols were transferred in this atom-economic reaction into the correspondi
- Alt, Isabel,Rohse, Philipp,Plietker, Bernd
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p. 3002 - 3005
(2014/01/06)
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- Pronounced catalytic effect of a micellar solution of sodium dodecyl sulfate (SDS) on the efficient C-S bond formation via an odorless thia-michael addition reaction through the in situ generation of S-alkylisothiouronium salts
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A pronounced catalytic effect of sodium dodecyl sulfate (SDS) was observed on the in situ production of 5-alkylisothiouronium salts via the reaction of primary, allyl and benzyl halides with thiourea in SDS droplets .Hydrolysis of the generated Salkylisot
- Firouzabadi, Habib,Iranpoor, Nasser,Abbasi, Mohammad
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experimental part
p. 755 - 766
(2009/11/30)
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- Thia-Michael addition using cheap and odorless S-alkylisothiouronium salts as thiol equivalents in water
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S-Alkylisothiouronium salt has been found to be a non-toxic, odorless and simply operational alternative of thiol for the thia-Michael addition with electron-deficient olefins. The reactions were carried out under alkaline conditions in water at room temperature within 5-20 minutes to afford the expected products in good to excellent yields. Georg Thieme Verlag Stuttgart.
- Zhao, Yan,Ge, Ze-Mei,Cheng, Tie-Ming,Li, Run-Tao
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p. 1529 - 1532
(2008/02/04)
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- Michael addition of masked thiolates to conjugated systems in aqueous media promoted by ammonium tetrathiomolybdate
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Thiolates generated in situ by the action of ammonium tetrathiomolybdate on alkyl halides, thiocyanates and disulfides undergo Michael addition to α,β-unsaturated esters, nitriles and ketones in water under neutral conditions.
- Devan, Naduthambi,Sureshkumar, Devarajalu,Beadham, Ian,Prabhu, Kandikere Ramaiah,Chandrasekaran, Srinivasan
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p. 2112 - 2115
(2007/10/03)
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- Regiochemical and Stereochemical Studies on Halocyclization Reactions of Unsaturated Sulfides
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The regiochemistry and stereochemistry for the halocyclization reactions of unsaturated benzyl sulfides have been examined as a function of tether length, type of unsaturation (carbon-carbon double bond versus carbon-carbon triple bond), substituents, and halogenating agent.Alkenyl sulfides were found to react with iodine or bromine at room temperature to give five-membered ring cycloadducts exclusively over those having four-membered rings, while for larger systems, six-membered ring products are formed preferentially over their five-membered ring isomers and exclusively over the seven-membered ring adducts.The endo- versus exo-regioselectivity of these alkenyl sulfide ring closure most likely reflects the difference in thermodynamic stabilities of the β-halo sulfide cycloadducts, which are able to equilibrate via a common episulfonium intermediate.The efficiency of cyclization process markedly drops off for these alkenyl sulfides as the tether length increases beyond four intervening carbon centers.Thus, while the halogenations of 3-butenyl sulfides and 4-pentenyl sulfides give high yields of cycloadducts, those of 5-hexenyl sulfides afford only small amounts of cyclized products and large quantities of acyclic dibromides.Conversely, the reactions of acetylenic sulfides with iodine give uniformly high yields and regiochemical control regardless of the tether length.Thus, 3-butynyl and 4-pentynyl sulfides cyclize cleanly to the five-membered ring while 5-hexynyl sulfides give exclusively the six-membered ring.The products arising from these alkynyl sulfide ring closures are believed to be formed under kinetic control.The methodology has been applied to the synthesis of unusual bicyclic β-lactams related to the penicillin family of antibiotics.
- Ren, Xiao-Feng,Turos, Edward,Lake, Charles H.,Churchill, Melvyn Rowen
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p. 6468 - 6483
(2007/10/03)
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- ORGANIC COMPOUNDS AND THEIR PHARMACEUTICAL USE
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There are disclosed pharmaceutical compounds of the formula: STR1 in which R 1 is halo-substituted alkyl;X is alkenylene; and R 1--X--contains 6 to 34 carbon atoms; R 2 is C 1-5 alkyl substituted by(i) optionally protected carboxyl, nit
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- Synthesis and Coordinating Properties of Ligands Designed for Modeling of the Active Site Zinc of Liver Alcohol Dehydrogenase
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Some tridentate ligands have been prepared for coordination of zinc(II) ions (or cobalt(II), which acts as a surrogate for Zn(II) ions) in a manner analogous to the coordination found in liver alcohol dehydrogenase.This entails coordination of the metal ion to two thiolates and an imidazole.The ligands must be sufficiently sterically hindered to prevent thiolate from acting as a bridging ligand between two metal ions.For some aspects of this work pyridine was used instead of imidazole.A trisubstituted benzene derivative, 3,5-bis(3-mercaptopropoxy)-N-benzamide (7) was prepared.Zn(II) complexes with 7 could not be characterized but the Co(II) complexes showed excellent spectral correlation with liver alcohol dehydrogenase in which Zn(II) has been replaced by Co(II).Several analogues of 7 have also been synthesized.Another ligand, 2,6-bispyridine (17), does provide a monomeric Zn(II) complex.The synthesis and coordination of various analogues of this system have been examined.The bis-alcohol, 2,6-bis(2-methyl-2-hydroxypropyl)pyridine (24), gives a stable pentacoordinate complex with Zn(NO3)2 and two water molecules.
- Kaptein, Bernard,Barf, G.,Kellogg, Richard M.,Bolhuis, F. Van
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p. 1890 - 1901
(2007/10/02)
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- A Facile Synthesis of Functionalised Organic Sulphides
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Thioiminium salts and organic halides or Michael acceptors, in the absence of solvent and at ambient temperature, give title compounds in excellent yields.
- Singh, Harjit,Batra, Manohar S.
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p. 1111 - 1112
(2007/10/02)
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