- Catalytic Synthesis of N-Unprotected Piperazines, Morpholines, and Thiomorpholines from Aldehydes and SnAP Reagents
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Commercially available SnAP (stannyl amine protocol) reagents allow the transformation of aldehydes and ketones into a variety of N-unprotected heterocycles. By identifying new ligands and reaction conditions, a robust catalytic variant that expands the substrate scope to previously inaccessible heteroaromatic substrates and new substitution patterns was realized. It also establishes the basis for a catalytic enantioselective process through the use of chiral ligands. SnAPcat! The identification of new ligands and reaction conditions provides a robust catalytic method for the synthesis of N-unprotected heterocycles using SnAP reagents. This catalytic variant expands the substrate scope to include previously inaccessible piperazines, morpholines, and thiomorpholines and establishes the basis for a catalytic enantioselective process through the use of chiral ligands.
- Luescher, Michael U.,Bode, Jeffrey W.
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supporting information
p. 10884 - 10888
(2015/09/15)
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- SnAP reagents for the transformation of aldehydes into substituted thiomorpholines - An alternative to cross-coupling with saturated heterocycles
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It's a SnAP! The transformation of aldehydes into N-unsubstituted 3-thiomorpholines provides a convenient alternative to metal-catalyzed cross-coupling reactions, which are generally unsuited to the functionalization of saturated N-heterocycles. A copper-mediated radical cyclization is the key to the mild conditions, high functional group tolerance, and broad substrate scope offered by these reagents. Copyright
- Vo, Cam-Van T.,Mikutis, Gediminas,Bode, Jeffrey W.
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supporting information
p. 1705 - 1708
(2013/04/10)
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- 1-(3-heterocyclyphenyl)-S-triazine-2,6,6-oxo or thiotrione herbicidal agents
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There is provided a 1-(3-heterocyclylphenyl)-s-triazine-2, 4,6-oxo or thiotrione compound having the structural formula I STR1 Further provided are a composition and a method comprising that compound for the control of undesirable plant species.
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- 1-(3-heterocyclylphenyl)-s-triazine-2,4,6-oxo or thiotrione herbicidal agents
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There is provided a 1-(3-heterocyclylphenyl)-s-triazine-2,4,6-oxo or thiotrione compound having the structural formula I STR1 Further provided are a composition and a method comprising that compound for the control of undesirable plant species.
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- 1-(3-heterocyclylphenyl)-s-triazine-2,4,6-oxo or thiotrione herbicidal agents
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There is provided a 1-(3-heterocyclylphenyl)-s-triazine-2,4,6-oxo or thiotrione compound having the structural formula I STR1 Further provided are a composition and a method comprising that compound for the control of undesirable plant species.
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- Synthesis of Amino Acids with Modified Principal Properties 3: Sulfur-Containing Amino Acids
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The synthesis and characterization of seven medium-sized, medium-polar, sulfur-containing amino acids are presented.The compounds were prepared with the objective of finding amino acids which possess physical and chemical properties such that their principal properties would be clearly different from those of previously known amino acids.The principal properties are determined as latent variables in principal component analysis of molecular property descriptors.The following amino acids were prepared in homochiral form from L-cysteine: (2R)-2-amino-3-(2-hydroxyethylsulfanyl)propanoic acid, (2R)-2-amino-3-(2-hydroxyethylsulfonyl)propanoic acid, (3R)-perhydro-1,4-thiazine-3-carboxylic acid and (3R)-1,1-dioxoperhydro-1,4-thiazine-3-carboxylic acid. (3R)-1-Oxoperhydro-1,4-thiazine-3-carboxylic acid was prepared in N,C protected form, but all attempts to obtain the free amino acid failed.The principal properties of this amino acid were determined on the racemic diastereomers obtained by oxidation of the racemic perhydro-1,4-thiazine-3-carboxylic acid prepared from 2-aminoethanethiol and ethyl 3-bromo-2-oxopropanoate.With the exception of (3R)-perhydro-1,4-thiazine-3-carboxylic acid for which the synthesis has been previously described, the amino acids described are new compounds.An improved synthesis of (3R)-perhydro-1,4-thiazine-3-carboxylic acid via the cyclization of (2R)-benzyl-2-amino-3-(2-hydroxyethylsulfanyl)propanoate under Mitsunobu conditions is presented.Full experimental details for the syntheses are given.The principal property scores of the synthesized sulfur-containing amino acids and of the structurally related 3-(2-aminoethyl)cysteine which was commercially available are given.
- Larsson, Ulf,Carlson, Rolf
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p. 517 - 525
(2007/10/02)
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