- Inexpensive multigram-scale synthesis of cyclic enamines and 3-N spirocyclopropyl systems
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Cyclic enamines are important synthons for many synthetic and pharmacological targets. Here, we report an inexpensive, catalyst-free, multigram-scale synthesis for cyclic enamines with exocyclic double bonds and four- to seven-membered rings. This strategy is more conducive to scale up, permissive of functionalization around the cyclic system, and less sensitive to the nature of the N-protecting group than previously-described methods for cyclic enamine synthesis. Further, we explore application of these enamines to the synthesis of highly-strained spirocyclic 3N-cyclopropyl scaffolds.
- Kumar, Pratik,Zainul, Omar,Laughlin, Scott T.
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supporting information
p. 652 - 656
(2018/02/07)
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- Synthesis of 2-carboxylated aza-ring derivatives through α-monohalogenation/ring-contraction of N-sulfonyl lactams
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2-Carboxylated aza-rings have been synthesized in two steps through a highly selective monohalogenation of N-sulfonylated lactams of various ring sizes (from 5- to 8-membered rings) followed by a ring contraction reaction. The selective monohalogenation of N-sulfonyl lactams has been achieved in modest to excellent yields (9 examples, 39–96%) using N-halogenosuccinimides via the in situ generation of trimethylsilyl ketene aminal derivatives. The so-obtained α-halogeno N-sulfonyl lactams were engaged in a ring opening/ring closing reaction in the presence of various alcohols or anilines under basic conditions affording 2-carboxylated aza-rings, such as azetidine, pyrrolidine or piperidine derivatives in high yields (24 examples, 61–99%).
- Sirindil, Fatih,Miaskiewicz, Solène,Kern, Nicolas,Lalaut, Arno,Felten, Anne-Sophie,Weibel, Jean-Marc,Pale, Patrick,Blanc, Aurélien
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p. 5096 - 5106
(2017/07/28)
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- An efficient synthesis of azetidines with (2-bromoethyl)sulfonium triflate
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Easily accessible arylglycine derivatives were cyclized to azetidines by using commercially available (2-bromoethyl)sulfonium triflate in a simple and mild procedure. The high-yielding reaction has a relatively broad scope and was extended to the synthesi
- Fritz, Sven P.,Moya, Juan F.,Unthank, Matthew G.,Mcgarrigle, Eoghan M.,Aggarwal, Varinder K.
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p. 1584 - 1590
(2012/06/29)
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- Enantiodivergent synthesis of N-protected azetidine-2-carboxylic acid
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A new route to both enantiomers of N-tosyl-azetidine-2- carboxylic acid has been developed from (R)-2-cyclohexylideneglyceraldehyde which proceeded with good overall yield and excellent enantiomeric purity.
- Biswas, Tanmoy,Mukherjee, Jyoti Prasad,Chattopadhyay, Shital K.
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p. 1416 - 1422,7
(2020/09/16)
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- Thermal Arndt-Eistert reactions of N-tosyl cyclic α-amino acids
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Thermal Arndt-Eistert reactions of N-tosyl cyclic α-amino acids were studied to explore the preparation of α,β-unsaturated esters bearing a terminal tosylamino group. For L-N-tosyl-aziridine 2-carboxylic acid and L-N-tosyl-azetidine 2-carboxylic acid, the corresponding (E)-α,β- unsaturated esters were obtained stereospecifically. Copyright Taylor & Francis, Inc.
- Jin, Jing Yi,Wu, Xue,Tian, Guan Rong
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p. 2535 - 2541
(2007/10/03)
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- Process for preparation of optically active n-substituted azetidine-2-carboxylic acids
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The object of the present invention is to produce an optically active N-substituted azetidine-2-carboxylic acid by an efficient, expedient and commercially profitable process. The present invention provides a production method of an optically active N-sub
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- Peptidyl aldehyde inhibitors of calpain incorporating P2-proline mimetics
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Four new peptidyl aldehydes bearing proline mimetics at the P2-position were synthesized and studied as inhibitors of calpain I, cathepsin B, and selected serine proteases. The ring size of the P2-constraining residue influenced the
- Donkor, Isaac O.,Korukonda, Rajani,Huang, Tien L.,LeCour Jr., Louis
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p. 783 - 784
(2007/10/03)
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- PROCESS FOR PREPARATION OF OPTICALLY ACTIVE N-SUBSTITUTED AZETIDINE-2-CARBOXYLIC ACIDS
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The object of the present invention is to produce an optically active N-substituted azetidine-2-carboxylic acid by an efficient, expedient and commercially profitable process. The present invention provides a production method of an optically active N-sub
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Page 10 - 11
(2008/06/13)
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- 3-Pyridyl enantiomers and their use as analgesics
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The present invention relates to a method of controlling pain in mammals, including humans, comprising administering to a mammal or patient in need of treatment thereof selected compounds of formula I: STR1 or a pharmaceutically acceptable salt thereof. The invention further relates to selected (R) and (S) compounds of formula I above which are useful as analgesics as well as neuronal cell death preventors and anti-inflammatories.
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- Novel chiral dirhodium catalysts derived from aziridine and azetidine carboxylic acid for intermolecular cyclopropanation reactions with methyl phenyldiazoacetate
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Three new chiral dirhodium(II) tetracarboxylate catalysts, based on azetidine- and aziridine-2-carboxylic acid, were prepared. Their selectivities in the cyclopropanation reaction of methyl phenyl-diazoacetate and olefins were determined in solvents of de
- Starmans, Wim A. J.,Thijs, Lambertus,Zwanenburg, Binne
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p. 629 - 636
(2007/10/03)
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- A New Anodic C-N Bond Forming Reaction Useful to Formation of Aziridine, Azetidine, and Pyrrolidine Rings
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Aziridine, azetidine, and pyrrolidine rings were formed in high yields by oxidation of the corresponding dimethyl α-(ω-tosylaminoalkyl)malonates in methanol containing KI as a mediator.
- Shono, Tatsuya,Matsumura, Yoshihiro,Katoh, Susumu,Ohshita, Jyoji
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p. 1065 - 1068
(2007/10/02)
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