- Incorporation of chlorinated analogues of aliphatic amino acids during cell-free protein synthesis
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3-Chloro-Abu and 4-chloro-Nva are biosynthetically incorporated into E. coli peptidyl-Pro cis-trans isomerase B, as substitutes for Val and Leu, respectively. The extent of incorporation is up to ~90%, and substituted protein is catalytically active. By contrast, 4-chloro-Val is not an effective replacement for Ile.
- Stigers, Dannon J.,Watts, Zachary I.,Hennessy, James E.,Kim, Hye-Kyung,Martini, Romeo,Taylor, Matthew C.,Ozawa, Kiyoshi,Keillor, Jeffrey W.,Dixon, Nicholas E.,Easton, Christopher J.
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Read Online
- EP300/CREBBP INHIBITOR
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The present invention provides a compound having excellent histone acetyltransferase inhibitory activity against EP300 and/or CREBBP, or a pharmacologically acceptable salt thereof. The compound is represented by the following formula (1) or a pharmacologically acceptable salt thereof: wherein ring Q1, ring Q2, R1, R2, R3 and R4 respectively have the same meanings as defined in the specification.
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Paragraph 0233; 0234; 0287; 0288
(2020/05/30)
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- Synthesis and evaluation of in vivo anti-hypothermic effect of all stereoisomers of the thyrotropin-releasing hormone mimetic: Rovatirelin Hydrate
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We discovered the orally active thyrotropin-releasing hormone (TRH) mimetic: (4S,5S)-5-methyl-N-{(2S)-1-[(2R)-2-methylpyrrolidin-1-yl]-1-oxo-3-(1,3-thiazol-4-yl)propan-2-yl}-2-oxo-1,3-oxazolidine-4-carboxamide 1 (rovatirelin). The central nervous system (CNS) effect of rovatirelin after intravenous (iv) administration is 100-fold higher than that of TRH. As 1 has four asymmetric carbons in its molecule, there are 16 stereoisomers. We synthesized and evaluated the anti-hypothermic effect of all stereoisomers of 1, which has the (4S),(5S),(2S),(2R) configuration from the N-terminus to the C-terminus, in order to clarify the structure?activity relationship (SAR) of stereoisomers. The (4R),(5R),(2R),(2S)-isomer 16 did not show any anti-hypothermic effect. Only the (4S),(5S),(2S),(2S)-isomer 10, which has the (2S)-2-methylpyrrolidine moiety at the C-terminus showed the anti-hypothermic effect similar to 1. Stereoisomers, which have the (5R) configuration of the oxazolidinone at the N-terminus and the (2R) configuration at the middle-part, showed a much lower anti-hypothermic effect than that of 1. On the other hand, stereoisomers, which have the (4R) configuration of the oxazolidinone at the N-terminus or the (2S) configuration of the C-terminus, have little influence on the anti-hypothermic effect.
- Kobayashi, Naotake,Sato, Norihito,Sugita, Katsuji,Takahashi, Kouji,Sugawara, Tamio,Tada, Yukio,Yoshikawa, Takayoshi
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- L-threonine-linked dihydroartemisinin-fluoroquinolone conjugates, intermediates thereof, and preparation methods and uses of conjugates and intermediates
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The invention discloses L-threonine-linked dihydroartemisinin-fluoroquinolone conjugates represented by formula I, intermediates represented by formula II, preparation methods of the compounds of formula I and formula II, and uses of the compounds of the formula I in the preparation of drugs for resisting mycobacterium tuberculosis or/and drugs for lowering blood lipids.
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Paragraph 0081-0086
(2019/12/08)
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- PROCESS AND INTERMEDIATES FOR SYNTHESIS OF PEPTIDE COMPOUNDS
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Disclosed is a new process and intermediates for preparing dipyrrolidine peptide compounds such as, for example, rapastinel. Advantageously, the process may be industrially scalable and cost-effective and use less toxic reagents and/or solvents. Further, the process may be used to prepare peptide compounds having improved purity.
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Paragraph 0176; 0177
(2019/02/13)
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- Strategy for O-alkylation of serine and threonine from serinyl and threoninyl acetic acids by photoinduced decarboxylative radical reactions: Connection between serine/threonine and carbohydrates/amino acids at the side chain
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O-Alkylations of serine and threonine derivatives at the hydroxy group were achieved using photoinduced decarboxylative radical reactions of serinyl and threoninyl acetic acids with an organic photocatalyst without racemization under mild conditions. Photoinduced decarboxylative radical additions of serinyl and threoninyl acetic acids to electron-deficient alkenes provided linked serine and threonine with carbohydrates and amino acids at the side chain. In addition, O-methylations containing deuterium and O-benzylation of serine were performed under similar photochemical conditions.
- Yamamoto, Takashi,Iwasaki, Tomoya,Morita, Toshio,Yoshimi, Yasuharu
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p. 3702 - 3709
(2018/04/14)
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- SPIRO-LACTAM NMDA MODULATORS AND METHODS OF USING SAME
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Disclosed are compounds having potency in the modulation of NMDA receptor activity. Such compounds can be used in the treatment of conditions such as depression and related disorders. Orally delivered formulations and other pharmaceutically acceptable delivery forms of the compounds, including intravenous formulations, are also disclosed.
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Page/Page column 51; 53
(2018/03/28)
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- SPIRO-LACTAM AND BIS-SPIRO-LACTAM NMDA RECEPTOR MODULATORS AND USES THEREOF
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Disclosed are compounds having potency in the modulation of NMDA receptor activity. Such compounds can be used in the treatment of conditions such as depression and related disorders. Orally delivered formulations and other pharmaceutically acceptable delivery forms of the compounds, including intravenous formulations, are also disclosed.
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Page/Page column 87
(2018/03/28)
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- PROCESSES FOR SYNTHESIS OF DIPYRROLIDINE PEPTIDE COMPOUNDS
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Disclosed is a new process for preparing dipyrrolidine peptide compounds such as, for example, GLYX-13. Advantageously, the process may be industrially scalable and cost-effective and use less toxic reagents and/or solvents. Further, the process may be used to prepare peptide compounds having improved purity.
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Paragraph 00108-00113
(2017/12/27)
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- Highly stable triple helix formation by homopyrimidine (l)-acyclic threoninol nucleic acids with single stranded DNA and RNA
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Acyclic (l)-threoninol nucleic acid (aTNA) containing thymine, cytosine and adenine nucleobases were synthesized and shown to form surprisingly stable triplexes with complementary single stranded homopurine DNA or RNA targets. The triplex structures consist of two (l)-aTNA strands and one DNA or RNA, and these triplexes are significantly stronger than the corresponding DNA or RNA duplexes as shown in competition experiments. As a unique property the (l)-aTNAs exclusively form triplex structures with DNA and RNA and no duplex structures are observed by gel electrophoresis. The results were compared to the known enantiomer (d)-aTNA, which forms much weaker triplexes depending upon temperature and time. It was demonstrated that (l)-aTNA triplexes are able to stop primer extension on a DNA template, showing the potential of (l)-aTNA for antisense applications. This journal is
- Kumar, Vipin,Kesavan, Venkitasamy,Gothelf, Kurt V.
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supporting information
p. 2366 - 2374
(2015/03/04)
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- SPIRO-LACTAM NMDA RECEPTOR MODULATORS AND USES THEREOF
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Disclosed are compounds having enhanced potency in the modulation of NMDA receptor activity. Such compounds are contemplated for use in the treatment of conditions such as depression and related disorders. Orally available formulations and other pharmaceutically acceptable delivery forms of the compounds, including intravenous formulations, are also disclosed.
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Paragraph 0099
(2014/08/19)
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- SPIRO-LACTAM NMDA RECEPTOR MODULATORS AND USES THEREOF
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Disclosed are compounds having enhanced potency in the modulation of NMDA receptor activity. Such compounds are contemplated for use in the treatment of conditions such as depression and related disorders. Orally available formulations and other pharmaceutically acceptable delivery forms of the compounds, including intravenous formulations, are also disclosed.
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Paragraph 00121; page 45
(2014/08/19)
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- N -(2-Oxo-3-oxetanyl)carbamic acid esters as N-acylethanolamine acid amidase inhibitors: Synthesis and structure-activity and structure-property relationships
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The β-lactone ring of N-(2-oxo-3-oxetanyl)amides, a class of N-acylethanolamine acid amidase (NAAA) inhibitors endowed with anti-inflammatory properties, is responsible for both NAAA inhibition and low compound stability. Here, we investigate the structure-activity and structure-property relationships for a set of known and new β-lactone derivatives, focusing on the new class of N-(2-oxo-3-oxetanyl)carbamates. Replacement of the amide group with a carbamate one led to different stereoselectivity for NAAA inhibition and higher intrinsic stability, because of the reduced level of intramolecular attack at the lactone ring. The introduction of a syn methyl at the β-position of the lactone further improved chemical stability. A tert-butyl substituent in the side chain reduced the reactivity with bovine serum albumin. (2S,3R)-2-Methyl-4-oxo-3-oxetanylcarbamic acid 5-phenylpentyl ester (27, URB913/ARN077) inhibited NAAA with good in vitro potency (IC50 = 127 nM) and showed improved stability. It is rapidly cleaved in plasma, which supports its use for topical applications.
- Duranti, Andrea,Tontini, Andrea,Antonietti, Francesca,Vacondio, Federica,Fioni, Alessandro,Silva, Claudia,Lodola, Alessio,Rivara, Silvia,Solorzano, Carlos,Piomelli, Daniele,Tarzia, Giorgio,Mor, Marco
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experimental part
p. 4824 - 4836
(2012/07/03)
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- Total synthesis of (-)-lemonomycin
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When life gives you lemons: An efficient and convergent enantioselective total synthesis of (-)-lemonomycin, which shows potent activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF), is presented. The key reaction steps are a Hosomi-Sakurai-type cyclization, a thermodynamically controlled Pictet-Spengler reaction, and a glycosidation reaction with lemonose (see scheme). Copyright
- Yoshida, Atsushi,Asakawa, Tomohiro,Hamashima, Yoshitaka,Kan, Toshiyuki,Akaiwa, Michinori,Yokoshima, Satoshi,Fukuyama, Tohru
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supporting information
p. 11192 - 11195,4
(2012/12/12)
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- Part II. Development of novel colchicine-derived immunosuppressants with improved pharmacokinetic properties
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We have developed a new series of immunosuppressant with improved pharmacokinetic properties as the second-generation of colchicine analogs, which were designed based on the privileged structure derived from our previous work. In particular, we identified an analog (14), which exhibited a potent in vitro activity (IC50: 5 nM) in MLR and excellent in vivo efficacy in the Zymosan A-induced arthritis model, in the Carrageenan-induced edema model and in the local lymph node assay (LLNA). Analog 14 also revealed a good oral bioavailability (F: 67.3%) in BALB/c mice.
- Chang, Dong-Jo,Lee, Sujin,Jang, Jaebong,Suh, Young-Ger,Kim, Soon-Ok,Kim, Wan-Joo
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p. 6750 - 6755,6
(2012/12/12)
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- Papain-catalyzed peptide bond formation: Enzyme-specific activation with guanidinophenyl esters
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The substrate mimetics approach is a versatile method for small-scale enzymatic peptide-bond synthesis in aqueous systems. The protease-recognized amino acid side chain is incorporated in an ester leaving group, the substrate mimetic. This shift of the specific moiety enables the acceptance of amino acids and peptide sequences that are normally not recognized by the enzyme. The guanidinophenyl group (OGp), a known substrate mimetic for the serine proteases trypsin and chymotrypsin, has now been applied for the first time in combination with papain, a cheap and commercially available cysteine protease. To provide insight in the binding mode of various Z-XAA-OGp esters, computational docking studies were performed. The results strongly point at enzyme-specific activation of the OGp esters in papain through a novel mode of action, rather than their functioning as mimetics. Furthermore, the scope of a model dipeptide synthesis was investigated with respect to both the amino acid donor and the nucleophile. Molecular dynamics simulations were carried out to prioritize 22 natural and unnatural amino acid donors for synthesis. Experimental results correlate well with the predicted ranking and show that nearly all amino acids are accepted by papain.
- de Beer, Roseri J.A.C.,Zarzycka, Barbara,Amatdjais-Groenen, Helene I.V.,Jans, Sander C.B.,Nuijens, Timo,Quaedflieg, Peter J.L.M.,van Delft, Floris L.,Nabuurs, Sander B.,Rutjes, Floris P.J.T.
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experimental part
p. 2201 - 2207
(2012/05/05)
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- Synthesis and evaluation of lysophosphatidylserine analogues as inducers of mast cell degranulation. Potent activities of lysophosphatidylthreonine and its 2-deoxy derivative
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In response to various exogenous stimuli, mast cells (MCs) release a wide variety of inflammatory mediators stored in their cytoplasmic granules and this release initiates subsequent allergic reactions. Lysophosphatidylserine (lysoPS) has been known as an exogenous inducer to potentiate histamine release from MCs, though even at submicromolar concentrations. In this study, through SAR studies on lysoPS against MC degranulation, we identified lysoPT, a threonine-containing lysophospholipid and its 2-deoxy derivative as novel strong agonists. LysoPT and its 2-deoxy derivative induced histamine release from MCs both in vitro and in vivo at a concentration less than one-tenth that of lysoPS. Notably, lysoPT did not activate a recently proposed lysoPS receptor on MCs, GPR34, demonstrating the presence of another undefined receptor reactive to both lysoPS and lysoPT that is involved in MC degranulation. Thus, the present strong agonists, lysoPT and its 2-deoxy derivative, will be useful tools to understand the mechanisms of lysoPS-induced activation of degranulation of MCs. 2009 American Chemical Society.
- Iwashita, Masazumi,Makide, Kumiko,Nonomura, Taro,Misumi, Yoshimasa,Otani, Yuko,Ishida, Mayuko,Taguchi, Ryo,Tsujimoto, Masafumi,Aoki, Junken,Arai, Hiroyuki,Ohwada, Tomohiko
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experimental part
p. 5837 - 5863
(2010/03/24)
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- Enantioselective total synthesis of callipeltoside A: two approaches to the macrolactone fragment
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The enantioselective total synthesis of callipeltoside A is described. Two syntheses of the macrolactone subunit are included: the first relies upon an Ireland-Claisen rearrangement to generate the trisubstituted olefin geometry and the second utilizes an enantioselective vinylogous aldol reaction for this purpose. Enantioselective syntheses of the sugar and chlorocyclopropane side chain fragments are also disclosed. The relative and absolute stereochemistry of this natural product was determined by fragment coupling with the two enantiomers of the side chain fragment.
- Evans, David A.,Burch, Jason D.,Hu, Essa,Jaeschke, Georg
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p. 4671 - 4699
(2008/09/21)
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- Aqueous phase mono-protection of amines and amino acids as N-benzyloxycarbonyl derivatives in the presence of β-cyclodextrin
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A simple and selective protection of amines/amino acids with Cbz-Cl has been achieved in aqueous phase with catalytic amounts of β-cyclodextrin in high yields at room temperature. This reaction proceeds without the formation of any by-products and has advantages over existing methods.
- Pavan Kumar,Somi Reddy,Narender,Surendra,Nageswar,Rama Rao
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p. 6393 - 6396
(2007/10/03)
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- Synthesis and biological activity of piperazine-Based dual MMP-13 and TNF-α converting enzyme inhibitors
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A series of novel MMP-13 and TNF-α converting enzyme inhibitors based on piperazine 2-hydroxamic acid scaffolds are described. The TACE, MMP-1 and MMP-13 activity of these inhibitors as well as the effect of substitution of the piperazine nitrogen and the P-1′ benzyloxy tailpiece is discussed. Moderate in vivo activity is observed with several members of this group.
- Letavic, Michael A.,Barberia, John T.,Carty, Thomas J.,Hardink, Joel R.,Liras, Jennifer,Lopresti-Morrow, Lori L.,Mitchell, Peter G.,Noe, Mark C.,Reeves, Lisa M.,Snow, Sheri L.,Stam, Ethan J.,Sweeney, Francis J.,Vaughn, Marcie L.,Yu, Chul H.
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p. 3243 - 3246
(2007/10/03)
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- Benzyl 4,6-dimethoxy-1,3,5-triazinyl carbonate as N-protecting reagent
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A new active carbonate ester, benzyl 4,6-dimethoxy-1,3,5-triazinyl carbonate (Z-DMT), was prepared, and found to be a useful reagent for the introduction of benzyloxycarbonyl group into amines. Since Z-DMT is neither unstable nor irritating, it is practically useful.
- Hioki, Kazuhito,Fujiwara, Miho,Tani, Shohei,Kunishima, Munetaka
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- An aldol-based approach to the asymmetric synthesis of L-callipeltose, the deoxyamino sugar of L-callipeltoside A.
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[reaction: see text] The L-callipeltose subunit of L-callipeltoside A has been synthesized in 10 steps and 13% overall yield from D-threonine. The key steps are a highly diastereoselective Felkin anti aldol addition to a methyl ketone and a selective methylation of a secondary alcohol in the presence of a secondary carbamate.
- Evans,Hu,Tedrow
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p. 3133 - 3136
(2007/10/03)
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- Selective inhibitors of aggrecanase in osteoarthritis treatment
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This invention relates to a method of treatment for osteoarthritis involving inhibitors of aggrecanase that demonstrate IC50s of less than 20 nM and demonstrate differential potency against matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs or reprolysins). This invention also relates to compounds, methods of treatment and composition of Formula I: or a therapeutically acceptable salt thereof, whereinX is carbon or nitrogen;R1 and R2 are independently selected from the group consisting of hydrogen, hydroxy, and methyl, wherein at least one of R1 and R2 is methyl;R3 and R4 are independently selected from the group consisting of hydrogen, hydroxy, and methyl, or R3 and R4 may be taken together to form a carbonyl group; andR5 and R6 are independent substituents in the ortho, meta, or para positions and are independently selected from the group consisting of hydrogen, halogen, cyano, methyl, and ethyl;with the provisos:when X is carbon, then R7 and R8 are both hydrogen and at least one of R1, R2, R3, and R4 is hydroxy;when X is carbon and R5 is para-halo, then at least one of R6, R3, and R4 is not hydrogen;when X is nitrogen, then R8 is not present and R7 is hydrogen or a group of the formula:wherein, Y is -CH2-NH2 or -NH-CH3; andwhen X is nitrogen and R7 is H, then R3 and R4 are taken together to form a carbonyl group.
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- Synthesis of acyclic nucleoside and nucleotide analogues from amino acids: A convenient approach to a PMEA-PMPA hybrid
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Nonracemic amino alcohols derived from common amino acids have been used to assemble acyclic nucleoside and nucleotide analogues with control of absolute stereochemistry. Both (R)- and (S)-2-amino-1-propanol, readily available from D- or L-alanine, were used to prepare the nucleoside analogues (R)- and (S)-9-[1- methyl-2-hydroxyethyl]adenine, and then the nucleotide analogues (R)- and (S)-9-[1-methyl-2-phosphonomethoxyethyl]adenine. In a similar fashion, the CBz derivative of L-threonine was used to prepare first (1R,2R)-9-[1-hydroxymethyl-2-hydroxypropyl]adenine, and then the bis phosphonomethoxy derivative. The bis phosphonate derived from threonine represents a unique structural hybrid of PMEA and PMPA, both of which have well established antiviral activity. (C) 2000 Elsevier Science Ltd.
- Jeffery, Arlen L.,Kim, Jae-Hun,Wiemer, David F.
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p. 5077 - 5083
(2007/10/03)
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- Oxazaborolidine-mediated asymmetric reduction of 1,2-diaryl-2- benzyloxyiminoethanones and 1,2-diarylethanediones
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Highly enantioselective reduction of 1,2-diaryl-2- benzyloxyiminoethanones and 1,2-diarylethanediones was conducted using oxazaborolidine derived from L-threonine and borane complexes to give β- imino alcohols and 1,2-diaryl-1,2-ethanediols in high enantiomeric purity. Subsequent reduction of the imino functionality of the former products afforded either syn- or anti-2-amino-1,2-diarylethanols in high enantiomeric purity by choosing appropriate reduction methods.
- Shimizu, Makoto,Tsukamoto, Keiko,Matsutani, Takayuki,Fujisawa, Tamotsu
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p. 10265 - 10274
(2007/10/03)
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- Synthesis of the Peptide Fragment of Pseudobactin
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Synthesis of the peptide fragment, L-Lys-D-threo-β-OH-Asp-L-Ala-D-allo-Thr-L-Ala-N-OH-D-cOrn, of pseudobactin (2) is reported.By utilizing 2-ethoxy-1-(ethoxycarbonyl)-1,2-dihydroquinoline (EEDQ) as a coupling reagent, peptide bonds were constructed without requiring protection of hydroxyl groups.To access the D-allo-Thr residue in the peptide fragment of pseudobactin, the Thr residue in N-Cbz-L-Ala-D-Thr-L-Ala-O-t-Bu (4b) was converted to a peptidyl oxazoline using Burgess' reagent.Hydrolysis of the oxazoline with 1 N HCl followed by base-catalyzed acyl migration then provided the D-allo-Thr analog 4a.
- Okonya, John F.,Kolasa, Teodozyj,Miller, Marvin J.
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p. 1932 - 1935
(2007/10/02)
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- Improved efficiency and selectivity in peptide synthesis: Use of triethylsilane as a carbocation scavenger in deprotection of t-butyl esters and t-butoxycarbonyl-protected sites
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The use of triethylsilane as a carbocation scavenger in the presence of trifluoroacetic acid in dichloromethane leads to increased yields, decreased reaction times, simple work-up and improved selectivity for the deprotection of t-butyl ester and t-butoxycarbonyl sites in protected amino-acids and peptides in the presence of other acid-sensitive protecting groups such as the benzyloxycarbonyl, 9-fluorenylmethoxycarbonyl, O- and S-benzyl and t-butylthio groups.
- Mehta, Anita,Jaouhari, Rabih,Benson, Timothy J.,Douglas, Kenneth T.
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p. 5441 - 5444
(2007/10/02)
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- 3,5-substituted 4,5-dihydroisoxazoles as transglutaminase inhibitors
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The present invention is directed to certain 3,5 substituted, 4,5-dihydroisoxazoles, and methods for their use. These compounds are transgulatminase inhibitors, and are particularly effective in the inhibition of epidermal transglutaminase and the treatment of acne.
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- PEPTIDE SYNTHESIS CATALYZED BY NATIVE PROTEINASE K IN WATER-MISCIBLE ORGANIC SOLVENTS WITH LOW WATER CONTENT
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Rection of Ac-Tyr-OEt with HBr.Gly-NH2, catalysed by free proteinase K in various water-miscible organic solvents in the presence of triethylamine and 5 mol percent of water, was studied.Some aliphatic alcohols and acetonitrile proved to be suitable solvents.The effect of water content (2 percent - 20 percent) on the synthesis of Ac-Tyr-Gly-NH2 was studied using acetonitrile as solvent.Lowering of the water content to 5 percent or 2 percent led to almost 100 percent yield of the desired dipeptide; higher water content accelerated the reaction reducing at the same time the yield of Ac-Tyr-Gly-NH2 due to the concurrent hydrolysis of the ester Ac-Tyr-OEt.No reaction was observed in the absence of base (triethylamine), wereas an excess of base only retarded the reaction.The enzyme is capable of catalyzing the peptide bond synthesis with N-acylamino acids or N-acyl peptides as acylating components, which may contain all types of L-amino acid residues (except Pro) in the P1 position.However, the peptide bond synthesis depends strongly on the amino component composition, particularly on the amino acid residue in the P'1 position.Only amides of glycine and of hydrophillic amino acids were acylated with Ac-Tyr-OEt; amides of hydrophobic amino acids enter the reaction only reluctantly or not at al.The presence of Leu or Phe in position P'2 and Leu in position P'3 has not so negative effect on acylation of the amino component as has in presence in the P'1 position.The choice of protecting groups for the α-carboxyl of the amino component is restricted only to amide and in some cases its undesired enzymatic removal was observed.Unprotected peptides seem to be suitable amino components.
- Cerovsky, Vaclav,Martinek, Karel
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p. 2027 - 2041
(2007/10/02)
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- Composition containing a penem or carbapenem antibiotic and the use of the same
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Administration of an N-acylated amino acid in association with a penem or carbapenem antibiotic relieves or eliminates the renal problems associated with administration of the antibiotic alone. The amino acid derivative and antibiotic may be formulated together as a composition or administered separately, either simultaneously or sequentially.
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- π-Facial selection in intermolecular Diels-Alder reactions: Total syntheses of (+)-actinobolin and (+)-5,6,10-triepi-actinobolin
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Syntheses of both 5,6,10-triepi-actinobolin and the antibiotic actinobolin are described in which a homochiral diene prepared from L-threonine is employed as a key componenet in a Diels-Alder reaction with an acetylenic dienophile. While the Diels-Alder reaction of this diene with methyl propiolate furnished the cycloadduct required for the synthesis of (+)-actinobolin as the minor diastereomer, the completion of the synthesis required but seven additional steps. The steric and stercoelectronic features responsible for the π-facial course of this cycloaddition reaction are discussed along with the various steps required to complete the syntheses of the title compounds.
- Kozikowski,Nieduzak,Konoike,Springer
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p. 5167 - 5175
(2007/10/02)
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- Composition containing a penem or carbapenem antibiotic
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Administration of an N-acylated amino acid in association with a penem or carbapenem antibiotic relieves or eliminates the renal problems associated with administration of the antibiotic alone. The amino acid derivative and antibiotic may be formulated together as a composition or administered separately, either simultaneously or sequentially. The composition may be prepared by simple mixing.
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-
- On the Synthesis of Benzyloxycarbonyl Amino Acids
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Dibenzyl dicarbonate and 1-benzyloxycarbonyl-benzothiazole are proposed as efficient new acyl donors for the introduction of the benzyloxycarbonyl group into amines for the reversible protection of amino functions particularly in peptide synthesis.
- Wuensch, E.,Graf, W.,Keller, O.,Keller, W.,Wersin, G.
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p. 958 - 960
(2007/10/02)
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- Method for preparing N-benzyloxycarbonyl amino acids containing additional functionality
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Poly(oxyalkylene) glycols and polymer-supported poly(oxyalkylene) alcohols are employed as phase-transfer reagents in blocking primary amino functionality of alkali metal salts of amino acids with a benzyloxycarbonyl group.
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- New Amino-protective Reagents for t-Butoxycarbonylation and Benzyloxycarbonylation of Amines and Amino Acids
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New amino-protective reagents for t-butoxycarbonylation and benzyloxycarbonylation of amines and amino acids have been developed. t-Butyl 2-pyridyl carbonate and t-butyl S-(2-pyridyl) thiocarbonate react cleanly with various amines and amino acids to afford N-Boc amines and N-Boc amino acids in high yields.Benzyl 2-pyridyl carbonate and O-benzyl S-(2-pyridyl) thiocarbonate are also found to be very effective in the benzyloxycarbonylation of amino acids.
- Kim, Sunggak,Lee, Jae In,Yi, Kyu Yang
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p. 3570 - 3575
(2007/10/02)
-