- Facile Access to 1,4-Disubstituted Pyrrolo[1,2- a ]pyrazines from α-Aminoacetonitriles
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An efficient and practical synthetic protocol for the synthesis of 1,4-disubstituted pyrrolo[1,2- a ]pyrazine derivatives is described that originates from α-substituted pyrroloacetonitriles which, in turn, are readily available from aryl and alkyl aldehydes. The α-pyrroloacetonitriles were subjected to a Friedel-Crafts acylation with methyl chlorooxoacetate followed by reduction of the nitrile group under Pd-catalyzed hydrogenation conditions and finally aromatization with DDQ leading to the desired pyrrolo[1,2- a ]pyrazine derivatives. This method was generalized and successfully applied to various aryl, heteroaryl, and alkyl substrates. The developed protocol provides direct and convenient access to 1,4-disubstituted ring systems in moderate to good overall yields (51-68percent) without the need for purification of the intermediates. Further functionalization via the stepwise halogenation (bromination, iodination) and nitration was also demonstrated. In addition, the potential of the ester functionality for elaboration was demonstrated by manipulating into heterocyclic ring systems, exemplified by conversion into benzoxazole derivatives.
- Basha, Mushkin,Belema, Makonen,Dhar, T. G. Murali,Gupta, Anuradha,Gupta, Arun Kumar,Indasi, Gopi Kumar,Karmakar, Ananta,Mathur, Arvind,Meanwell, Nicholas A.,Ramalingam, Sridharan,Rampulla, Richard
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supporting information
p. 441 - 449
(2020/01/23)
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- Titanium-Catalyzed Cyano-Borrowing Reaction for the Direct Amination of Cyanohydrins with Ammonia
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α-Aminonitrile was an important building block in natural products and key intermedia in organic chemistry. Herein, the direct amination of cyanohydrins with the partner of ammonia to synthesis N-unprotected α-aminonitriles is developed. The reaction proceeds via titanium-catalyzed cyano-borrowing reaction, which features high atom economy and simple operation. A broad range of ketone or aldehyde cyanohydrins was tolerated with ammonia, and the N-unprotected α-aminonitriles were synthesis with moderate to high yields under mild reaction conditions.
- Li, Qing-Hua,Li, Zhao-Feng,Tao, Jing,Li, Wan-Fang,Ren, Li-Qing,Li, Qian,Peng, Yun-Gui,Liu, Tang-Lin
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supporting information
p. 8429 - 8433
(2019/10/14)
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- Gold-catalyzed oxidative couplings of two indoles with one aryldiazo cyanide under oxidant-free conditions
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Gold-catalyzed oxidative couplings of two indoles and one α-cyano gold carbene to form bis(indolyl)methane derivatives are described. Two different indoles are compatible with these reactions to provide reasonable yields. A plausible mechanism is postulated to rationalize the experimental data including product distributions, D2O labeling, and the significant effects of gold catalysts and cyano groups.
- Singh, Rahulkumar Rajmani,Liu, Rai-Shung
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supporting information
p. 4593 - 4596
(2017/04/28)
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- Gold-catalyzed [3+2]-annulations of α-aryl diazonitriles with ynamides and allenamides to yield 1-amino-1H-indenes
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Gold-catalyzed [3+2]-annulations of α-aryl diazonitriles with ynamides and allenamides yield 1-amino-1H-indenes in two distinct pathways; the success of these annulations relies on the high electrophilicity of α-cyano arylgold carbenes to activate an ionic pathway.
- Singh, Rahulkumar Rajmani,Pawar, Samir Kundlik,Huang, Min-Jie,Liu, Rai-Shung
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supporting information
p. 11434 - 11437
(2016/09/23)
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- An efficient and scalable synthesis of the spirocyclic glycine transporter inhibitor GSK2137305
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An efficient and scalable synthesis of a glycine transporter inhibitor is presented. The key steps in the synthetic sequence are the formation of a spirocyclic imidazolidinone from an -amino nitrile and a cyclic ketone and an arylation of 4-methyl imidazo
- Graham, Jonathan P.,Langlade, Nathalie,Northall, John M.,Roberts, Alastair J.,Whitehead, Andrew J.
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experimental part
p. 44 - 48
(2011/09/15)
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- Development of a new α-aminonitrile synthesis
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α-Aminonitriles are prepared upon reaction of aryl carboxaldehydes with LiHMDS and acetone cyanohydrin. This new method provides a general route to the synthesis of various substituted α-aminoarylacetonitriles in high yield and purity, and avoids the use of the highly toxic cyanide salts.
- Chu, Guo-Hua,Gu, Minghua,Gerard, Baudouin,Dolle, Roland E.
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p. 4583 - 4590
(2007/10/03)
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