- Stereoselective Synthesis of Protected l - Allo -Enduracididine and l -Enduracididine via Asymmetric Nitroaldol Reaction
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The diastereoselecetive and scalable synthesis of cyclic guanidine-containing nonproteinoginic amino acids, enduracididines, has been achieved. Both diastereomers, l - allo -enduracididine and l -enduracididine, were prepared via catalyst-controlled asymmetric nitroaldol reaction with the aldehyde precursor derived from l -aspartic acid. The cyclic guanidine of di-Cbz-protected l - allo -enduracididine was fully protected with an allyl group to suppress nucleophilic side reactions. Introduced allyl group was efficiently removed via π-allylpalladium chemistry without attaching the Cbz group on the cyclic guanidine moiety.
- Doi, Takayuki,Ganesan, A.,Masuda, Yuichi,Ohsawa, Kosuke,Thomas, Carys,Tokunaga, Takuya,Zhao, Hongbin
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supporting information
p. 942 - 948
(2020/03/23)
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- Multigram-scale and column chromatography-free synthesis of L-azetidine-2-carboxylic acid for the synthesis of nicotianamine and its derivatives
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Multigram-scale synthesis of L-azetidine-2-carboxylic acid from L-aspartic acid was achieved in 13 conventional synthetic steps, without the need for purification by silica-gel column chromatography and expensive reagents. Nicotianamine and its fluorescence-labeled derivatives could be obtained from this synthetic strategy.
- Takaishi, Tomohiro,Wakisaka, Kyosuke,Vavricka, Christopher J.,Kiyota, Hiromasa,Izumi, Minoru
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p. 2126 - 2134
(2019/04/04)
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- Stereoselective synthesis of unsaturated and functionalized L-NHBoc amino acids, using wittig reaction under mild phase-transfer conditions
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The stereoselective synthesis of a new amino acid phosphonium salt was described by quaternization of melting triphenylphosphine with the β-iodo NHBoc-amino ester, derived from l-aspartic acid. The deprotection of the carboxylic acid function to afford the phosphonium salt with a free carboxylic acid group was achieved by a palladium-catalyzed desallylation reaction. This phosphonium salt was used in the Wittig reaction with aromatic or aliphatic aldehydes and trifluoroacetophenone, under solid-liquid phase-transfer conditions in chlorobenzene and in the presence of K3PO4 as weak base, to afford the corresponding unsaturated amino acids without racemization. Thus, the reaction with substituted aldehydes allows to graft various functionalized groups on the lateral chain of the amino acid, such as trifluoromethyl, cyano, nitro, ferrocenyl, boronato, or azido. In addition, the reaction of the amino acid Wittig reagent with α,β-unsaturated aldehydes leads to amino acids bearing a diene on the lateral chain. Finally, this amino acid phosphonium salt appears to be a new powerful tool for the preparation of unsaturated and non-proteinogenic α-amino acids, directly usable for the synthesis of customized peptides.
- Remond, Emmanuelle,Bayardon, Jerome,Ondel-Eymin, Marie-Joelle,Juge, Sylvain
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p. 7579 - 7587
(2012/10/29)
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- A PREPARATION METHOD OF SITAGLIPTIN
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The present invention relates to a preparation method of sitagliptin, and more particularly, to a method of preparing sitagliptin using L-aspartic acid having a (R)-beta amino acid structure by mild amide formation, by the use of industrially applicable halo isopropylmagnesium, and by removal of amine protecting group using Pd/C and H2 and carbonyl reduction using reducing agent.
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Page/Page column 16
(2012/11/13)
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- Synthesis of (-)-dihydropinidine, (2S,6R)-isosolenopsin and (+)-monomorine via a chiral synthon from l-aspartic acid
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The use of a β-amino aldehyde derived from l-aspartic acid as a chiral synthon to construct 2,6-disubstituted piperidines is described. The synthesis of (-)-dihydropinidine·HCl, (2S,6R)-isosolenopsin·HCl and (+)-monomorine has been achieved from this chiral synthon using a Wittig reaction followed by hydrogenation (reductive cyclization) as the key steps.
- Reddy, Chada Raji,Latha, Bellamkonda
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experimental part
p. 1849 - 1854
(2012/02/05)
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- A rapid access to the spiroaminoketal framework
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A convergent and stereoselective synthesis of 1-oxa-7-azaspiro[5.5]undecane is described. This functional new spiroheterocycle is readily available from acetone N,N-dimethylhydrazone via a double alkylation and subsequent spiroannulation process. Georg Thieme Verlag Stuttgart.
- Tursun, Ahmatjan,Aboab, Bettina,Martin, Anne-Sophie,Sinibaldi, Marie-Eve,Canet, Isabelle
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p. 2397 - 2399
(2007/10/03)
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- Utility of tetrathiomolybdate and tetraselenotungstate: Efficient synthesis of cystine, selenocystine, and their higher homologues
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Efficient synthesis of cystine, selenocystine, and their higher homologues like homo and bishomo amino acid derivatives from natural amino acid derivatives using tetrathiomolybdate and tetraselenotungstate reagents under mild and neutral conditions is reported. The generality of the reaction has been studied by capping various groups to amino and carboxyl components of canonical amino acids.
- Bhat, Ramakrishna G.,Porhiel, Emmanuel,Saravanan, Vadivelu,Chandrasekaran, Srinivasan
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p. 5251 - 5253
(2007/10/03)
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- A Simple and Convenient Synthesis of β-Aspartates and γ-Glutamates
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A simple and convenient, high yield synthesis of ω-esters of aspartic as well as glutamic acid has been developed, using tetrafluoroboric acid as catalyst. (13)C-NMR data of the products are given.
- Albert, Rainer,Danklmaier, Johann,Hoenig, Helmut,Kandolf, Harald
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p. 635 - 637
(2007/10/02)
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- Chirally Selective Hydrolysis of D,L-Amino Acid Esters by Alkaline Protease
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Alcalase selectively catalyses the hydrolysis of D,L-amino acid methyl and benzyl ester to provide L-amino acid and D-amino acid ester with high optical purity.
- Chen, Shui-Tein,Wang, Kung-Tsung,Wong, Chi-Huey
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p. 1514 - 1516
(2007/10/02)
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