- Palladium and Lewis-Acid-Catalyzed Intramolecular Aminocyanation of Alkenes: Scope, Mechanism, and Stereoselective Alkene Difunctionalizations
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An expansion of methodologies aimed at the formation of versatile organonitriles, via the intramolecular aminocyanation of unactivated alkenes, is herein reported. Importantly, the need for a rigid tether in these reactions has been obviated. The ease-of-synthesis and viability of substrates bearing flexible backbones has permitted for diastereoselective variants as well. We demonstrated the utility of this methodology with the formation of pyrrolidones, piperidinones, isoindolinones, and sultams. Furthermore, subsequent transformation of these motifs into medicinally relevant molecules is also demonstrated. A double crossover 13C-labeling experiment is consistent with a fully intramolecular cyclization mechanism. Deuterium labeling experiments support a mechanism involving syn-addition across the alkene.
- Pan, Zhongda,Wang, Shengyang,Brethorst, Jason T.,Douglas, Christopher J.
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p. 3331 - 3338
(2018/03/13)
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- The synthesis of arylcyanamides: A copper-catalyzed consecutive desulfurization and C-N cross-coupling strategy
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A one pot highly efficient and simple protocol for the construction of aromatic cyanamides from thiourea via desulphurization/C-N cross coupling using a cheap, readily available and air stable copper source as a catalyst has been described. Various iodobenzenes could give their respective C-N cross-coupled products in good to excellent yields under optimized reaction conditions. Further, the substrate scope has been explored.
- Boddapati, S. N. Murthy,Polam, Naresh,Mutchu, Baby Ramana,Bollikolla, Hari Babu
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supporting information
p. 918 - 922
(2018/02/03)
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- A novel one-pot synthesis of isothiocyanates and cyanamides from dithiocarbamate salts using environmentally benign reagent tetrapropylammonium tribromide
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A highly efficient and simple protocol for the synthesis of isothiocyanates and cyanamides from their respective amines in the presence of a mild, efficient, and non-toxic reagent tetrapropylammonium tribromide is described. High environmental acceptability of the reagents, cost effectiveness and high yields are the important attributes of this methodology.
- Kuotsu, Neivotsonuo Bernadette,Jamir, Latonglila,Phucho, Tovishe,Sinha, Upasana Bora
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p. 832 - 841
(2018/01/17)
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- Environmentally benign one-pot synthesis of cyanamides from dithiocarbamates using I2 and H2O2
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An environmentally benign reaction is devised for the synthesis of cyanamides from dithiocarbamate salts using iodine and H2O 2. Taylor & Francis Group, LLC.
- Jamir, Latonglila,Sinha, Upasana Bora,Nath, Jayashree,Patel, Bhisma K.
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p. 951 - 958
(2012/02/01)
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- Bromineless bromine as an efficient desulfurizing agent for the preparation of cyanamides and 2-aminothiazoles from dithiocarbamate salts
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In a one-pot procedure, bromineless brominating reagent 1,1'-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been used as a desulfurizing agent in the preparation of organic cyanamides and substituted thiazoles starting from dithiocarbamic acid salts. In this approach, alkyl/aryl isothiocyantes were first obtained by the desulfurization of dithiocarbamic acid salts with EDPBT. The in situ-generated isothiocyanates reacts with an aqueous ammonia, forming alkyl or aryl thioureas, which on subsequent oxidative desulfurization with EDPBT led to the formation of corresponding cyanamides in good yields. Alternatively, an efficient one-pot synthesis of substituted thiazoles has been achieved by the condensation of the in situ-generated 1-aryl thioureas with the in situ-generated -bromoketones from ketones, again using EDPBT. The reagent EDPBT can be easily prepared from the readily available reagents. Desulfurizing ability dominates over its brominating ability for substrates amenable to bromination.
- Yella, Ramesh,Kavala, Veerababurao,Patel, Bhisma K.
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p. 792 - 805
(2011/04/22)
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- Copper(I)-catalyzed cascade synthesis of 2-arylsulfanyl-arylcyanamides
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We have developed a ligand-assisted copper(I)-catalyzed two sequential heteroarylation sequence. An intramolecular S-arylation is followed by an intermolecular N-arylation leading to the direct synthesis of N-aryl-2-aminobenzothiazoles. In most cases however, the 2-arylsulfanyl- arylcyanamide was the major product obtained via an intramolecular C-S bond formation, associated with C-S bond breakage, followed by an intermolecular S-arylation. The selectivity of this ligand-assisted reaction is quite different as compared to that of ligand-free reactions and the rates are much faster giving good yields of products. Various cyanamides can be prepared in excellent yields from their corresponding 1-substituted thioureas with or without the assistance of a ligand with a catalytic quantity of copper(I).
- Sahoo, Santosh K.,Jamir, Latonglila,Guin, Srimanta,Patel, Bhisma K.
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experimental part
p. 2538 - 2548
(2010/12/29)
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- An efficient synthesis of cyanamide from amine promoted by a hypervalent iodine(III) reagent
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In a one-pot strategy we have achieved an efficient method for the synthesis of organic cyanamides starting from dithiocarbamic acid salts/amines. In this strategy the in situ generated alkyl or aryl isothiocyanates, obtained by the desulfurization of dithiocarbamic acid salts with diacetoxyiodobenzene (DIB) react with aqueous ammonia forming alkyl or aryl thiourea which on subsequent oxidative desulfurization with DIB led to the formation of corresponding cyanamide in good yields. Mild reaction conditions, shorter reaction time, an environmentally benign protocol, and easy isolation of the desired product make the present methodology a suitable alternative for the preparation of various organic cyanamides.
- Ghosh, Harisadhan,Yella, Ramesh,Ali, Abdur Rezzak,Sahoo, Santosh K.,Patel, Bhisma K.
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experimental part
p. 2407 - 2410
(2009/07/26)
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- A one-pot preparation of cyanamide from dithiocarbamate using molecular iodine
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An efficient one-pot method for the synthesis of cyanamides from dithiocarbamate salts via a double desulfurization strategy using molecular iodine is disclosed. Dithiocarbamates, by the action of iodine yield isothiocyanates in situ, which on treatment with aqueous NH3 give thioureas. The thioureas so generated undergo further oxidative desulfurization with I2 giving corresponding cyanamides in good yields. Environmental benignity, cost effectiveness and high yields are the important attributes of this one pot procedure. The Royal Society of Chemistry 2009.
- Nath, Jayashree,Patel, Bhisma K.,Jamir, Latonglila,Sinha, Upasana Bora,Satyanarayana
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experimental part
p. 1503 - 1506
(2010/05/18)
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