- Synthesis of ω-tert-butyl esters of aspartic acid and glutamic acid via B,B-difluoroboroxazolidones
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B,B-Difluoroboroxazolidones (DFBONs) were synthesized for the first time from salts of amino acid and BF3·Et2O, and their properties were examined. DFBONs were used in selective preparation of Glu(OBu(t)) and Asp(OBu(t)) in good yields under catalysis with BF3·Et2O and H3PO4. Amberlite XAD-2 resin was successfully employed to purify the above amino acid derivatives.
- Wang, Jidong,Okada, Yoshio,Wang, Zongmu,Wang, Yuhong,Li, Wei
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Read Online
- ANTI-CD40 ANTIBODY DRUG CONJUGATES
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Provided herein are anti-CD40 antibody drug conjugates comprising a radical of Formula (I), wherein R1, R2, and R3 are as defined herein. Further provided are anti-CD40 antibody drug conjugates of Formula (II), wherein Z, R, AA1, AA2, AA3, m, p, q, n, w, R1, R2, and R3 are as defined herein. Further provided are pharmaceutical compositions and kits thereof, and methods of using same.
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Paragraph 00149
(2019/06/17)
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- PROCESSES FOR PREPARATION OF (S)-TERT-BUTYL 4,5-DIAMINO-5-OXOPENTANOATE
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Provided are processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate, or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof. Also provided are solid forms of various intermediates and products obtained from the processes.
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Paragraph 00353
(2019/03/12)
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- Fluorescent mimics of cholesterol that rapidly bind surfaces of living mammalian cells
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Mammalian cells acquire cholesterol, a critical membrane constituent, through multiple mechanisms. We synthesized mimics of cholesterol, fluorescent N-alkyl-3β-cholesterylamine-glutamic acids, that are rapidly incorporated into cellular plasma membranes compared with analogous cholesteryl amides, ethers, esters, carbamates, and a sitosterol analogue. This process was inhibited by ezetimibe, indicating a receptor-mediated uptake pathway.
- Hymel, David,Cai, Sutang,Sun, Qi,Henkhaus, Rebecca S.,Perera, Chamani,Peterson, Blake R.
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supporting information
p. 14624 - 14627
(2015/09/28)
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- Mild oxidative cleavage of 9-BBN-protected amino acid derivatives
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Protection of the amino acid moiety using 9-BBN is an effective method to enable side chain manipulations in synthesis of complex amino acids. We investigated the standard, mild method for deprotection of the 9-BBN group in methanolic chloroform, and found that it relies on a slow oxidation mediated by molecular oxygen. Building on this insight, we have developed a method that allows for a fast and selective deprotection using simple peroxy acid reagents. After Fmoc protection, products were isolated in >90% yield for a series of amino acid derivatives, including a galactosylated derivative of hydroxylysine. A representative set of 9-BBN-protected amino acid derivatives were efficiently deprotected using peracid reagents in excellent yields. Deprotection is orthogonal with several common protecting groups. Its tolerance of highly acid sensitive groups, such as trityl-protected amides and glycosidic linkages, is especially notable.
- Ankner, Tobias,Norberg, Thomas,Kihlberg, Jan
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p. 3767 - 3770
(2015/06/16)
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- A mild removal of Fmoc group using sodium azide
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A mild method for effectively removing the fluorenylmethoxycarbonyl (Fmoc) group using sodium azide was developed. Without base, sodium azide completely deprotected Nα-Fmoc-amino acids in hours. The solvent-dependent conditions were carefully studied and then optimized by screening different sodium azide amounts and reaction temperatures. A variety of Fmoc-protected amino acids containing residues masked with different protecting groups were efficiently and selectively deprotected by the optimized reaction. Finally, a biologically significant hexapeptide, angiotensin IV, was successfully synthesized by solid phase peptide synthesis using the developed sodium azide method for all Fmoc removals. The base-free condition provides a complement method for Fmoc deprotection in peptide chemistry and modern organic synthesis. Graphical Abstract: [Figure not available: see fulltext.]
- Chen, Chun-Chi,Rajagopal, Basker,Liu, Xuan Yu,Chen, Kuan Lin,Tyan, Yu-Chang,Lin, Fui,Lin, Po-Chiao
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p. 367 - 374
(2014/03/21)
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- SYNTHETIC CHOLESTERYLAMINE-LINKER DERIVATIVES FOR AGENT DELIVERY INTO CELLS
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Synthetic cholesterylamine-linkers can include derivatives of cholesterol, cholesteryl, or sitosteryl coupled through the linker to an agent for delivery into cells. The cholesterylamines are thought to mimic cholesterol in the capacity and mechanism for enhanced entry into cells. The configuration of the cholesterylamine-linker that is thought to provide for enhanced entry into cells includes a cholesterylamine that is coupled to a linker from the amine, and which linker includes a negative charge at a spatial distance from the amine of the cholesterylamine.
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Page/Page column 31-32
(2011/02/24)
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- The Synthesis of the High-Potency Sweetener, NC-00637. Part 3: The Glutamyl Moiety and Coupling Reactions
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The synthesis of the high-potency sweetener, NC-00637 (1), required selective preparation of the γ-protected glutamic acid. Coupling of the three components could be performed in any order, but the final route involved N-acylation of the protected L-glutamic acid with the acid chloride derived from (S)-2-methylhexanoic acid. Activation of the α-carboxyl group allowed condensation with 5-amino-2-cyanopyridine (4). Saponification of the γ-ester 19 then provided the sweetener 1.
- Ager, David J.,Babler, Scott,Erickson, Robert A.,Froen, Diane E.,Kittleson, Jeannine,Pantaleone, David P.,Prakash, Indra,Zhi, Ben
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- Hydrolysis of amino acid diesters
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The present invention provides a method for preparing an amino acid monoester from an amino acid diester without the use of an enzyme. Particularly, the method involves hydrolysis of an amino acid diester in the presence of a non-enzyme additive and under reaction conditions that affect selective hydrolysis of the α-ester group. The reaction conditions comprise a specific pH, temperature, and vapor pressure.
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- Structure-based design of nonpeptidic thrombin inhibitors: Exploring the D-pocket and the oxyanion hole
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Structure-activity relationships for new members of a class of nonpeptidic, low-molecular-weight inhibitors of thrombin, a key serine protease in the blood coagulation cascade, are described. These compounds, which originate from X-ray-structure-based design, feature a conformationally rigid, bi- or tricyclic core from which side chains diverge into the four major binding pockets (distal D, proximal P, recognition or specificity Sl, and oxyanion hole O) at the thrombin active site (Fig. 1). Phenylamidinium is the side chain of choice for the S1 pocket, while the most active inhibitors orient an i-Pr group into the P-pocket (Table 1). The key step in the synthesis of the inhibitors is the construction of the central bi- or tricyclic scaffold by 1,3-dipolar cycloaddition of an in situ prepared azomethine ylide and an N-substituted maleimide (Schemes 1-3, and 8-10). One series of compounds was designed to explore the binding features of the large hydrophobic D pocket. This pocket provides space for lipophilic residues as bulky as benzhydryl groups. A new strategy was developed, allowing introduction of these sterically demanding substituents very late in the synthesis (Schemes 5 and 6). Benzhydryl derivative (±)-2 was found to be the most selective member (Ki (trypsin)/Ki (thrombin) = 1200) of this class of nonpeptidic thrombin inhibitors, while the 'dipiperonyl' analog (±)-3 (Ki = 9 nM, 7.60-fold selectivity) displays the highest potency of all compounds prepared so far (Table 1). A second series of inhibitors features side chains designed to orient into the oxyanion hole and to undergo H-bonding with the backbone NH groups lining the catalytic site of the enzyme. Unfortunately, neither activity nor selectivity could be substantially improved by introduction of these substituents (Table 2), Presumably, the high degree of pre-organization and the rigidity of the tightly bound scaffolds prevents the new substituents from assuming a position that would allow favorable interactions in the oxyanion hole. However, the oxyanion hole and the S1' pocket next to it were found to be capable of accommodating quite large groups, which leaves much room for further exploration.
- Betschmann, Patrick,Sahli, Stefan,Diederich, Francois,Obst, Ulrike,Gramlich, Volker
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p. 1210 - 1245
(2007/10/03)
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