- Synthesis of novel 3D-rich α-amino acid-derived 3-pyrazolidinones
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Synthetic approaches towards novel 3-pyrazolidinone derivatives functionalized at positions N(1) and/or C(5) were studied. 5-Aminoalkyl-3-pyrazolidinones were prepared in four steps from N-protected glycines via Masamune-Claisen homologation, reduction, O
- Glava?, Jaka,Dahmann, Georg,Po?gan, Franc,Ri?ko, Sebastijan,?tefane, Bogdan,Svete, Jurij,Gro?elj, Uro?
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p. 715 - 726
(2018/01/17)
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- A mild titanium-catalyzed synthesis of functionalized amino coumarins as fluorescence labels
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In contrast to Bronsted and other Lewis acids ClTi(OiPr)3 is especially suited to catalyze the formation of amino-substituted coumarins from aminophenols and functionalized β-oxo esters in a Pechmann condensation. This straightforward protocol allows the synthesis of fluorescence labels and false fluorescent neurotransmitters.
- Wirtz, Lisa,Kazmaier, Uli
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supporting information; experimental part
p. 7062 - 7065
(2012/01/05)
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- Chain extension of amino acid skeletons: Preparation of ketomethylene isosteres
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Ketomethylene isosteric replacements for peptide bonds were generated through a zinc carbenoid-mediated chain extension reaction in which a variety of amino acid-derived β-keto esters are converted to γ-keto esters in a single step. The reaction tolerates a variety of protecting groups and amino acid side chains with no epimerization of the amino acid stereocenter.
- Theberge, Cory R.,Zercher, Charles K.
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p. 1521 - 1527
(2007/10/03)
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- Process for preparing optically active 4-hydroxy-2-pyrrolidone
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A process for preparing optically active 4-hydroxy-2-pyrrolidone comprising asymmetrically hydrogenating an N-substituted-4-amino-3-oxobutanoic ester represented by formula (I): STR1 wherein R1 represents a benzyloxycarbonyl group, the benzene
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- Baker's yeast reduction of N-protected methyl 4-amino-3-oxobutanoates and 3-oxopentanoates
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Baker's yeast reduction of N-tert-butoxycarbonyl (Boc) or N-benzyloxycarbonyl (Cbz) protected methyl 4-amino-3-oxopentanoates 4b-e and 4-amino-3-oxobutanoates 7a,b stereoselectively afforded the erythro-hydroxy esters 5b-e and (R)-hydroxy esters 8a,b, res
- Hashiguchi,Kawada,Natsugari
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p. 403 - 408
(2007/10/02)
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- Intramolecular N-H, O-H, and S-H Insertion Reactions. Synthesis of Heterocycles from α-Diazo β-Keto Esters
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Several aspects of the Rh2(OAc)4-catalyzed intramolecular N-H, O-H, and S-H insertion reactions have been studied.Examination of the effect of ring size revealed that four-, five- and six-membered nitrogen heterocycles can be efficiently prepared from the corresponding α-diazo β-keto ester precursors (9a-c), whereas competing C-H insertion prevented formation of the seven-membered heterocycle.Variations in solvent, temperature, and catalyst concentration were found to play an important role in determining the product distribution in the cyclization of the 6-carbamoyl 2-diazo 3-keto ester 9c.The intramolecular X-H insertion reaction has also been successful in the synthesis of oxygen (39) and sulfur (49) heterocycles as well as a heterocycle containing two (N, O) heteroatoms (34).
- Moyer, Mikel P.,Feldman, Paul L.,Rapoport, Henry
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p. 5223 - 5230
(2007/10/02)
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