- A convenient preparation of (2SR,3S)-3-amino-2-hydroxy-4-phenylbutanoic acid; an important peptide bond isostere
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We present an efficient synthesis of N-Z-(2SR,3S)-3-amino-2-hydroxy-4- phenylbutanoic acids by hydroxylation of an enolate derived from methyl (3S)N-Z-3-amino-4-phenylbutanoate with oxodiperoxymolybdenum (pyridine) (hexamethyl phosphoric triamide) complex
- May, Barnaby C.H.,Abell, Andrew D.
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- O-N intramolecular alkoxycarbonyl migration of typical protective groups in hydroxyamino acids
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O-N Intramolecular alkoxycarbonyl (carbonate-carbamate) migration was found to occur as a common reaction of hydroxyamino acids under mild basic aqueous conditions with no formation of side products. Carbonate protective groups migrate to produce amino-pr
- Skwarczynski, Mariusz,Sohma, Youhei,Noguchi, Mayo,Kimura, Tooru,Hayashi, Yoshio,Kiso, Yoshiaki
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p. 2542 - 2545
(2007/10/03)
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- Acylation of alkyl halides and amino aldehydes with a phosphane oxide-based d1-synthon
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Alkyl iodides and α-amino aldehydes can be homologated to the corresponding methyl esters and β-amino methyl esters, including β-amino-α-hydroxy methyl esters, using lithiated (dimethoxymethyl) diphenylphosphane oxide. The primary α,α-(dimethoxy) diphenylphosphane oxides obtained by this Horner-Wittig type process collapse to give the target esters under proton-catalyzed conditions in the presence of water. Detailed and carefully conducted mechanistic studies revealed that the diphenylphosphane oxide group is activated by protonation, and acts as the initial leaving group in this process. In the cases of adducts derived from the reaction of the phosphane oxide-stabilized anion with α-amino aldehydes, homologation to the β-amino- and β-amino-α-hydroxy methyl esters can be achieved by KOtBu-mediated elimination to the intermediate O,O-ketene acetals. These may either be allowed to react with water under acidic conditions to yield the β-amino methyl esters, or may be treated under the Sharpless asymmetric dihydroxylation conditions to directly furnish the β-amino-α-hydroxy methyl esters. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Bruenjes, Marco,Kujat, Christof,Monenschein, Holger,Kirschning, Andreas
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p. 1149 - 1160
(2007/10/03)
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- Lithiated dimethoxymethyl diphenyl phosphine oxide, a versatile formiate carbanion equivalent
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Aldehydes are homologated to the corresponding α-hydroxy methyl esters using lithiated dimethoxymethyl diphenyl phosphine oxide. The primary addition product of this Horner-Wittig process collapses to the corresponding α-hydroxy ester under proton-catalyzed conditions.
- Monenschein, Holger,Brünjes, Marco,Kirschning, Andreas
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p. 525 - 527
(2007/10/03)
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- Azobenzene-containing, peptidyl α-ketoesters as photobiological switches of α-chymotrypsin
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Three photoswitchable, peptidomimetic inhibitors of α-chymotrypsin have been synthesised. The compounds comprise an azobenzene, an α-ketoester and L-phenylalanine. The compounds were photoisomerised to give enriched states of the (E) and (Z) isomers and t
- Harvey, Andrew J,Abell, Andrew D
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p. 9763 - 9771
(2007/10/03)
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- Inactivation of serine protease, α-chymotrypsin by fluorinated phenylalanine analogues
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Fluorinated phenylalanine analogues were found to be slow-binding or reversible competitive inhibitors of α-chymotrypsin. A series of these compounds were designed to inactivate α-chymotrypsin as a result of the formation of hydrogen-bonding between fluorine atom of the inhibitors and the amide protons known as oxy-anion hole in the active-site of serine and cysteine proteases.
- Ohba, Tsuyoshi,Ikeda, Eitatsu,Takei, Hisashi
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p. 1875 - 1880
(2007/10/03)
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- Stereoselection in the Synthesis of threo- and erythro-3-Amino-2-hydroxy-4-phenyl-butanoic Acid using Chiral Acetal Templates
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Boron trifluoride-diethyl ether mediated addition of trimethylsilylcyanide (TMSCN) to the chiral acetals derived from Z-L- and Z-D-phenyl alaninal, Z-N-benzyloxycarbonyl), and (+)-(2S,4S)- and (-)-(2R,4R)-2,4-pentanediol stereoselectivity gave the four st
- Herranz, Rosario,Castro-Pichel, Julia,Vinuesa, Soledad,Garcia-Lopez, Ma. Teresa
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p. 938 - 939
(2007/10/02)
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- Tributyltin Cyanide, a Novel Reagent for the Stereoselective Preparation of 3-Amino-2-hydroxy Acids via Cyanohydrin Intermediates
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Reaction of tributyltin cyanide with optically active 2-N-benzyloxycarbonylamino aldehydes 1 gives the corresponding O-tributylstannyl cyanohydrins 2 and 3 stereoselectively.Compounds 2 and 3 are transformed in situ into the methyl 3-N-benzyloxycarbonylam
- Herranz, Rosario,Castro-Pichel, Julia,Garcia-Lopez, Teresa
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p. 703 - 706
(2007/10/02)
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