- ANTHELMINTIC DEPSIPEPTIDE COMPOUNDS
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The present invention provides cyclic depsipeptide compounds of formula (I) wherein the stereochemical configuration of at least one carbon atom bearing the groups Cy1, Cy2, R1, R2, R3, R4, Ra and Rb is inverted compared with the naturally occurring cyclic depsipeptide PF1022A. The invention also provides compositions comprising the compounds that are effective against parasites that harm animals. The compounds and compositions may be used for combating parasites in or on mammals and birds. The invention also provides for an improved method for eradicating, controlling and preventing parasite infestation in birds and mammals.
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Page/Page column 229
(2018/06/06)
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- ANTHELMINTIC DEPSIPEPTIDE COMPOUNDS
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The present invention provides cyclic depsipeptide compounds of formula (I) and compositions comprising the compounds that are effective against parasites that harm animals. The compounds and compositions may be used for combating parasites in or on mammals and birds. The invention also provides for an improved method for eradicating, controlling and preventing parasite infestation in birds and mammals.
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Page/Page column 210; 211
(2016/12/07)
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- Diastereoselective amidoallylation of glyoxylic acid with chiral tert-butanesulfinamide and allylboronic acid pinacol esters: Efficient synthesis of optically active γ,δ-unsaturated α-amino acids This work is dedicated to Dr. Masanori Sakamoto, Professor Emeritus of Meiji Pharmaceutical University, on the occasion of his 77th birthday (KIJU)
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A convenient synthesis of δ,γ-unsaturated amino acids has been developed. After a mixture of (R)-tert-butanesulfinamide and glyoxylic acid with molecular sieves in CH2Cl2 was stirred for 42 h at room temperature, allylboronic acid pinacol ester was added to the mixture to give (R)-2-((R)-tert-butanesulfinamido)pent-4-enoic acid with high diastereoselectivity. The corresponding reaction of (Z)-crotylboronic acid pinacol ester produced no product; however, that of (E)-crotylboronic acid pinacol ester produced (2R,3S)-2-((R)-tert-butylsulfinamido)-3-methylpent-4- enoic acid with excellent diastereoselectivity.
- Sugiyama, Shigeo,Imai, Saori,Ishii, Keitaro
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p. 1069 - 1074
(2013/10/08)
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- Peptides containing γ,δ,-dihydroxy-L-leucine
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(Chemical Equation Presented) (±)-Dehydroleucine was prepared and resolved by porcine kidney acylase. Under the conditions of the Sharpless asymmetric dihydroxylation (SAD), employing AD-mix-α, Nα- carbobenzyloxy-(2S)-4,5-dehydroleucine methyl ester (16)
- Edagwa, Benson J.,Taylor, Carol M.
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supporting information; experimental part
p. 4132 - 4136
(2009/09/26)
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- The asymmetric synthesis of allylglycine and other unnatural α-amino acid via zinc-mediated allylation of oximes in aqueous media
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Enantiomerically pure or highly enriched allylglycine and its chain-substituted analogs are easily accessible from the reaction of the sultam derivative of O-benzyl glyoxylic acid oxime with allylic bromides in the presence of powdered zinc in aqueous ammonium chloride.
- Hanessian, Stephen,Yang, Rui-Yang
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p. 5273 - 5276
(2007/10/03)
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- The total synthesis of eponemycin
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Eponemycin, an antibiotic with a highly potent and specific antitumor activity against B16 melanoma cells in vivo, has been synthesized. The framework of the western half of the molecule was built up from N-trityl- γ,δ-didehydroleucinal and the dilithium
- Schmidt,Schmidt
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p. 300 - 304
(2007/10/02)
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- Kinetic Resolution of Unnatural and Rarely Occuring Amino Acids: Enantioselective Hydrolysis of N-Acyl Amino Acids Catalyzed by Acylase I
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Acylase I (aminoacylase; N-acylamino-acid amidohydrolase, EC 3.5.1.14, from porcine kidney and the fungus Aspergillus) is broadly applicable enzymatic catalyst for the kinetic resolution of unnatural and rarely occuring α-amino acids.Its enantioselectivity for the hydrolysis of N-acyl L-α-amino acids is nearly absolute, yet it accepts substrates having a wide range of structure and functionality.This paper reports the initial rates of enzyme-catalyzed hydrolysis of over 50 N-acyl amino acids and analogues, the stabilities of the enzymes in aqueous and aqueous/organic solutions, and the effects of different acyl groups and metal ions on the rates of enzymatic hydrolysis.Eleven α-amino and α-methyl α-amino acids were resolved on a 2-29-g scale.Crude L- and D-amino acid products had generally >90percent ee.The utility of resolved amino acids as chiral synthons was illustrated by the preparation of (R)- and (S)-1-butene oxide and the diastereoselective (cis:trans, 7-8:1) iodolactonization of three 2-amino-4-alkenoic acid derivatives.
- Chenault, H. Keith,Dahmer, Juergen,Whitesides, George M.
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p. 6354 - 6364
(2007/10/02)
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