- Synthesis of functionalized poly(vinyl acetate) mediated by alkyne-terminated RAFT agents
-
Two new xanthates with alkyne functionalities were synthesized for the reversible addition fragmentation chain transfer (RAFT) polymerization of vinyl acetate (VAc). The new RAFT agents were fully characterized by 1H and 13C NMR spectroscopy. Unlike the alkyne terminated RAFT agent (AT-X1) the protected alkyne-terminated RAFT agent (PAT-X1) was able to conduct the RAFT polymerization of VAc with a good control over the molecular weight (MW) and relatively narrow MW distributions (n with conversion as well as the close agreement between Mn,th and Mn,GPC values confirmed the controlled features of the RAFT system. It is worth mentioning that the polymer dispersity remained very low (1H NMR, FTIR-ATR and UV-Vis absorption analysis. The "livingness" of the obtained polymer was confirmed by a successful chain extension experiment. The deprotection of the alkyne functionality in the PVAc, allowed a further copper catalyzed azide-alkyne [3 + 2] dipolar cycloaddition reaction (CuAAC) with an azido terminated-poly(ethylene glycol) (PEG-N3), to afford PVAc-PEG block-copolymers as a proof-of-concept.
- Góis, Joana. R.,Popov, Anatoliy V.,Guliashvili, Tamaz,Serra, Arménio C.,Coelho, Jorge F. J.
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-
Read Online
- Synthesis and antimicrobial evaluation of new nitric oxide-donating fluoroquinolone/oxime hybrids
-
A new series of nitric oxide-donating fluoroquinolone/oximes was prepared in this study. The nitric oxide release from the prepared compounds was measured using a modified Griess colorimetric method. The antitubercular evaluation of the synthesized compounds indicated that ketone derivatives 2b and 2e and oximes 3b and 3d exhibited somewhat higher activity than their respective parent fluoroquinolones. Mycobacterial DNA cleavage studies and molecular modeling of Mycobacterium tuberculosis DNA gyrase were pursued to explain the observed bioactivity. More important, antibacterial evaluation showed that oximes 3c–e are highly potent against Klebsiella pneumoniae, with minimum inhibitory concentration (MIC) values of 0.06, 0.08, and 0.034 μM, respectively, whereas ketone 2c and oxime 4c are more active against Staphylococcus aureus than ciprofloxacin (MIC values: 0.7, 0.38, and 1.6 μM, respectively). Notably, the antipseudomonal activities of compounds 2a and 4c were much higher than those of their respective parent fluoroquinolones.
- Aziz, Hossameldin A.,Moustafa, Gamal A. I.,Abuo-Rahma, Gamal El-Din A.,Rabea, Safwat M.,Hauk, Glenn,Krishna, Vagolu S.,Sriram, Dharmarajan,Berger, James M.,Abbas, Samar H.
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-
- Design, synthesis and agricultural evaluation of derivatives of N-Acyl-N-(m-fluoro-benzyl)-6-amino-coumarin
-
ABTRACT: This study aims to design and synthesize a series of N-Acyl-N-(m-fluoro- benzyl)-6- amino-coumarins through the principle of active substructure stitching, which are based on the core structure of N-(m-fluoro-benzyl)-6-amino-coumarin. The structures of target compounds e1–e25 have been characterized by 1H NMR, 13C NMR, ESI-MS and elemental analysis. Meanwhile, their agricultural activity have been evaluated in two weeds (Amaranth and Crabgrass) and four widespread noxious pathogens (V.mali, B.cinerea, F.axysporium and C.bacteria). The herbicidal activity results showed that almost all synthetic molecules have a greater impact on the stem system than on the root. Excellent inhibition rates were discovered from compounds e2–e5 and e20–e23 against Amaranth on stems, which were above 58percent(20 mg/L), 68percent(100 mg/L) respectively. Compounds e2 and e21 also exhibited striking inhibition on stems growth of both weeds. Anti-pathogenic activity showed that all the compounds exerted a better inhibitory activity on B.cinerea at 20 ppm compared to control carbendazim. All the heterocyclic substituted compounds (e17–e24, >57percent) made a better influence than the control (54.1percent) at the100 ppm. This research provides promising herbicidal and anti-pathogenic agents that have the better effects and can be potential for further development.
- Ding, Yin-hao,Dong, Jing-jing,Feng, Bai-cheng,Hao, Shuang-hong,Jin, Yan,Wei, Yan
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supporting information
(2020/08/19)
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- POLYCYCLIC COMPOUND ACTING AS IDO INHIBITOR AND/OR IDO-HDAC DUAL INHIBITOR
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The present invention provides polycyclic compounds as IDO inhibitors and/or dual inhibitors of IDO-HDAC. Specifically, the present invention provides compounds represented by the following formula (I), wherein each group is defined as described in the specification. The compounds have IDO inhibitory activity or IDO-HDAC dual inhibitory activity and can be used for preventing or treating diseases associated with IDO and/or IDO-HDAC activity or expression levels. At the same time, the compounds of the present invention can be combined with an antitumor antibody such as PD-1 and PD-L1, and such a combination can greatly increase the antitumor response rate of the antibody and broaden the types of tumors to be treated.
- -
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Paragraph 0368-0369
(2020/08/09)
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- Substituted Pyridazin-3(2 H)-ones as Highly Potent and Biased Formyl Peptide Receptor Agonists
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Herein we describe the development of a focused series of functionalized pyridazin-3(2H)-one-based formyl peptide receptor (FPR) agonists that demonstrate high potency and biased agonism. The compounds described demonstrated biased activation of prosurvival signaling, ERK1/2 phosphorylation, through diminution of the detrimental FPR1/2-mediated intracellular calcium (Cai2+) mobilization. Compound 50 showed an EC50 of 0.083 μM for phosphorylation of ERK1/2 and an approximate 20-fold bias away from Cai2+ mobilization at the hFPR1.
- Deora, Girdhar Singh,Qin, Cheng Xue,Vecchio, Elizabeth A.,Debono, Aaron J.,Priebbenow, Daniel L.,Brady, Ryan M.,Beveridge, Julia,Teguh, Silvia C.,Deo, Minh,May, Lauren T.,Krippner, Guy,Ritchie, Rebecca H.,Baell, Jonathan B.
-
supporting information
p. 5242 - 5248
(2019/05/28)
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- SPIROCYCLIC COMPOUNDS AS MODULATORS OF INDOLEAMINE 2,3-DIOXYGENASE
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The present invention relates to novel spirocyclic compounds of formulas (1) and (2) which act as modulators of indoleamine 2,3-dioxygenase (ID01) and to the use of said compounds in the prophylaxis and/or treatment of diseases or conditions mediated by indoleamine 2,3-dioxygenase. The invention further relates to pharmaceutical compositions comprising the novel compounds.
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Page/Page column 78
(2019/11/12)
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- Iron-Catalyzed Intramolecular C-H Amination of α-Azidyl Amides
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Iron-catalyzed intramolecular C-H amination of aliphatic azides has recently emerged as a powerful tool for the preparation of nitrogen heterocycles. This paper reports that α-azidyl amides can be converted in high efficacy to imidazolinone compounds via intramolecular C(sp3)-H amination by the action of a simple catalytic system composed of FeCl2 and a β-diketiminate ligand. The reactions provide a simple and atom-economical approach toward polysubstituted imidazolinones.
- Zhao, Xiaopeng,Liang, Siyu,Fan, Xing,Yang, Tonghao,Yu, Wei
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supporting information
p. 1559 - 1563
(2019/03/20)
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- Method and using tracer charged ion channel
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The invention provides compounds, compositions, methods, and kits for the treatment of pain, itch, and neurogenic inflammation.
- -
-
Paragraph 0227; 0229; 0230-0232
(2018/08/20)
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- Method for manufacturing isavuconazole or ravuconazole
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The invention provides a method for manufacturing a triazole compound isavuconazole or ravuconazole which is enriched by a diastereoisomer and enantiomer. The method comprises the following steps: a Reformatsky reaction is carried out between ketone and dihalogeno metal propionitrile; an enantiomer mixture is generated, and separation is carried out. The method can obviously reduce steps for synthesis of isavuconazole or ravuconazole, yield of products is improved, and production cost is reduced.
- -
-
Paragraph 0072; 0073
(2017/08/27)
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- Transition-Metal-Free Coupling of Alkynes with α-Bromo Carbonyl Compounds: An Efficient Approach towards β,γ-Alkynoates and Allenoates
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A direct transition-metal-free coupling between alkynes and α-bromo carbonyl compounds has been developed with ultraviolet (UV) light in aqueous media. This method represents a facile approach to synthetically useful β,γ-alkynyl esters and amides stereoselectively from two readily available starting materials. As an example of the synthetic application of the products, the alkynyl esters were readily converted into allenoates. Time for UV! A direct coupling between alkynes and α-bromo compounds has been developed with ultraviolet light in aqueous media (see scheme). This method represents a facile approach to synthetically useful β,γ-alkynyl esters and amides stereoselectively from two readily available starting materials.
- Liu, Wenbo,Chen, Zhengwang,Li, Lu,Wang, Haining,Li, Chao-Jun
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supporting information
p. 5888 - 5893
(2016/04/26)
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- Enantioselective synthesis of quaternary α-amino acids via l -tert-leucine-derived squaramide-catalyzed conjugate addition of α-nitrocarboxylates to enones
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Enantioselective Michael addition of tertiary α-nitroesters to β-unsubstituted vinyl ketones has been carried out in the presence of an l-tert-leucine-derived squaramide as organocatalyst. The products, quaternary α-nitroesters, were formed in excellent yield and moderate to good ee's in most cases. Scale-up of the reaction and synthetic applications of the products, including transformation to representative quaternary α-amino acids, have also been demonstrated.
- Bera, Kalisankar,Satam, Nishikant S.,Namboothiri, Irishi N. N.
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p. 5670 - 5680
(2016/07/14)
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- Asymmetric synthesis of 4,1-Benzoxazepine-2,5-Diones -Effect of the halogen of (2S)-A-Haloacids
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Novel chiral 4,1-benzoxazepine-2,5-diones have been unusually synthesized in a single step by exploiting the chiral pool methodology. Substituted anthranilic acids afford N-Acylanthranilic acids and (3R)-3-Alkyl-4,1- benzoxazepines-2,5-dione upon coupling with a-chloroacids or a-bromoacids, respectively.
- Rubab, Syeda Laila,Nisar, Bushra,Raza, Abdul Rauf,Ullah, Nisar,Tahir, Muhammad Nawaz
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p. 139 - 148
(2014/02/14)
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- Enantioselective construction of tetrasubstituted stereogenic carbons through bronsted base catalyzed michael reactions: α′-hydroxy enones as key enoate equivalent
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Catalytic and asymmetric Michael reactions constitute very powerful tools for the construction of new C-C bonds in synthesis, but most of the reports claiming high selectivity are limited to some specific combinations of nucleophile/electrophile compound types, and only few successful methods deal with the generation of all-carbon quaternary stereocenters. A contribution to solve this gap is presented here based on chiral bifunctional Bronsted base (BB) catalysis and the use of α′-oxy enones as enabling Michael acceptors with ambivalent H-bond acceptor/donor character, a yet unreported design element for bidentate enoate equivalents. It is found that the Michael addition of a range of enolizable carbonyl compounds that have previously demonstrated challenging (i.e., α-substituted 2-oxindoles, cyanoesters, oxazolones, thiazolones, and azlactones) to α′-oxy enones can afford the corresponding tetrasubstituted carbon stereocenters in high diastereo- and enantioselectivity in the presence of standard BB catalysts. Experiments show that the α′-oxy ketone moiety plays a key role in the above realizations, as parallel reactions under identical conditions but using the parent α,β-unsaturated ketones or esters instead proceed sluggish and/or with poor stereoselectivity. A series of trivial chemical manipulations of the ketol moiety in adducts can produce the corresponding carboxy, aldehyde, and ketone compounds under very mild conditions, giving access to a variety of enantioenriched densely functionalized building blocks containing a fully substituted carbon stereocenter. A computational investigation to rationalize the mode of substrate activation and the reaction stereochemistry is also provided, and the proposed models are compared with related systems in the literature.
- Badiola, Eider,Fiser, Bla,Gmez-Bengoa, Enrique,Mielgo, Antonia,Olaizola, Iurre,Urruzuno, Iaki,Garca, Jess M.,Odriozola, Jos M.,Razkin, Jess,Oiarbide, Mikel,Palomo, Claudio
-
supporting information
p. 17869 - 17881
(2015/02/19)
-
- Synthesis of β-hydroxy-δ-trichloromethyl-δ-valerolactones by intramolecular samarium/ytterbium diiodide-mediated Reformatsky reaction
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The synthesis of α-methyl-β-hydroxy-δ-trichloromethyl- δ-valerolactone was achieved by an intramolecular Reformatsky reaction. The cyclisation was effected by samarium diiodide or (for the first time) ytterbium diiodide. The diastereoselectivity of the reaction corresponds to earlier investigations by Molander. Consecutive stereoselective reactions during the esterification to the Reformatsky precursor 1,1,1-trichloropent-4-en-2-yl 2-bromopropanoate and in the Reformatsky reaction itself led to (3RS,4RS,6SR)-4-hydroxy-3-methyl-6-(trichloromethyl)tetrahydro-2H-pyran-2-one (3a) as the major formed diastereomer. The influence of the orientation of the substituents in the transition state is discussed.
- Schulze, Thies M.,Grunenberg, J?rg,Schulz, Stefan
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supporting information
p. 921 - 924
(2013/02/25)
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- Synthesis of enantiomerically enriched-bromonitriles from amino acids
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Two methods were investigated for the preparation of six chiral-bromonitriles with different optic purities. The nitrous deamination of amino acids gives-bromoacids, which react with chlorosulfonyl isocyanate followed by triethylamine to afford-bromonitriles with moderate enantiomeric excess. However, the dehydration of corresponding-bromoamids using thionyl chloride gives-bromonitriles with good enantiomeric excess up to 94%. The use of phosphoryl chloride instead of thionyl chloride results in more than 30% racemization as determined by high-performance liquid chromatograpic analysis.
- Tka, Najeh,Kraem, Jamil,Hassine, Bechir Ben
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p. 735 - 743
(2013/01/15)
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- HETEROCYCLYLAMINES AS PI3K INHIBITORS
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The present invention provides heterocyclylamine derivatives of Formula I: wherein the variables are defined herein, that modulate the activity of phosphoinositide 3-kinases (PI3Ks) and are useful in the treatment of diseases related to the activity of PI3Ks including, for example, inflammatory disorders, immune-based disorders, cancer, and other diseases.
- -
-
Paragraph 1063
(2013/03/26)
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- Direct amination of phenols under metal-free conditions
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Herein, we disclose the metal-free synthesis of arylamines via the direct amination of phenols using aminating reagents. This reaction procedure uses easy accessible aminating reagents and provides a versatile synthetic route to a broad range of arylamines with various functionalities in good to excellent yield. By using a two-step route of amination and oxidative coupling reaction, we synthesized three naturally occurring carbazole alkaloids: murrayafoline A, mukonine, and clausenine from two commercially available phenols. Georg Thieme Verlag Stuttgart · New York.
- Yu, Jianzhong,Wang, Yongtao,Zhang, Peizhi,Wu, Jun
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supporting information
p. 1448 - 1454
(2013/07/26)
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- Synthesis, enantioresolution, and activity profile of chiral 6-methyl-2,4-disubstituted pyridazin-3(2H)-ones as potent N-formyl peptide receptor agonists
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A series of chiral pyridazin-3(2H)-ones was synthesized, separated as pure enantiomers, and evaluated for N-formyl peptide receptor (FPR) agonist activity. Characterization of the purified enantiomers using combined chiral HPLC and chiroptical studies (circular dichroism, allowed unambiguous assignment of the absolute configuration for each pair of enantiomers). Evaluation of the ability of racemic mixtures and purified enantiomers to stimulate intracellular Ca 2+ flux in FPR-transfected HL-60 cells and human neutrophils and to induce β-arrestin recruitment in FPR-transfected CHO-K1 cells showed that many enantiomers were potent agonists, inducing responses in the sub-micromolar to nanomolar range. Furthermore, FPRs exhibited enantiomer selectivity, generally preferring the R-(-)-forms over the S-(+)-enantiomers. Finally, we found that elongation of the carbon chain in the chiral center of the active compounds generally increased biological activity. Thus, these studies provide important new information regarding molecular features involved in FPR ligand preference and report the identification of a novel series of FPR agonists.
- Cilibrizzi, Agostino,Schepetkin, Igor A.,Bartolucci, Gianluca,Crocetti, Letizia,Dal Piaz, Vittorio,Giovannoni, Maria Paola,Graziano, Alessia,Kirpotina, Liliya N.,Quinn, Mark T.,Vergelli, Claudia
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experimental part
p. 3781 - 3792
(2012/08/28)
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- Enantio-and diastereoselective oxidation of N-alkylimines using chiral-bromonitriles and hydrogen peroxide system
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Chiral-bromonitriles were prepared with good chemical and optical yields starting from natural-amino acids by dehydrating the corresponding α-bromoamides with thionyl chloride. The combined system-bromonitriles/ hydrogen peroxide was examined for the enantio-and diastereoselective oxidation of N-alkylimines in basic media at room temperature. The oxidation of N-tertiobutylarylimines leads to optically active oxaziridines with moderate enantiomeric excess. However, the oxidation of (S)-1-phenylethylarylimines affords the corresponding oxaziridines with good diasteromeric excess up to 97/3 as proved by gaseous-phase chromatography.
- Tka, Najeh,Kraem, Jamil,Hassine, Bechir Ben
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experimental part
p. 2994 - 3003
(2012/08/07)
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- Study of the lanthanide-catalyzed, aqueous, asymmetric Mukaiyama aldol reaction
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The development of efficient methods for the asymmetric Mukaiyama aldol reaction in aqueous solution has received great attention. We have developed a new series of chiral lanthanide-containing complexes that produce Mukaiyama aldol products with outstanding enantioselectivities. In this paper, we describe an optimized ligand synthesis, trends in stereoselectivity that result from changing lanthanide ions, and an exploration of substrate scope that includes aromatic and aliphatic aldehydes and silyl enol ethers derived from aromatic and aliphatic ketones.
- Mei, Yujiang,Averill, Derek J.,Allen, Matthew J.
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scheme or table
p. 5624 - 5632
(2012/09/05)
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- A new class of ligands for aqueous, lanthanide-catalyzed, enantioselective Mukaiyama aldol reactions
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The development of aqueous methods for generating enantiopure β-hydroxy carbonyl compounds is an important goal because these subunits compose many bioactive compounds and the ability to synthesize these groups in water has environmental and cost benefits. In this communication, we report a new class of ligands for aqueous, lanthanide-catalyzed, asymmetric Mukaiyama aldol reactions for the synthesis of chiral β-hydroxy ketones. Furthermore, we have used luminescence-decay measurements to unveil mechanistic information regarding the catalytic reaction via changes in water-coordination number. The precatalysts presented here yielded β-hydroxy carbonyls from aliphatic and aryl substrates with outstanding syn:anti ratios and enantiometric excesses of up to 49:1 and 97%, respectively.
- Mei, Yujiang,Dissanayake, Prabani,Allen, Matthew J.
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supporting information; experimental part
p. 12871 - 12873
(2010/11/16)
-
- Synthesis, antibacterial and antifungal activities of new chiral 5-alkyl-3-(1′-benzenesulfonylpyrrolidin-2′-yl)-4,5-dihydro-1,2, 4-oxadiazin-6-ones
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Chiral α-bromoacid chlorides can be easily prepared from amino acids. Their condensation with new 1-benzenesulfonylpyrrolidin-2-carboxamidoxime derived from proline lead to the corresponding O-(bromoacyl) amidoximes. The latter afforded new chiral 5-alkyl-3-(1′-benzenesulfonylpyrrolidin- 2′-yl)-4,5-dihydro-1,2,4oxadiazin-6-ones in good chemical yields via intramolecular cyclization in the presence of one equivalent of NaH. These new compounds were evaluated for their antibacterial and antifungal activities using micro-dilution tests against some strains of bacteria and fungi. Our compounds showed an excellent antibacterial activity, which is better than the drug levofloxacin.
- Tka, Najeh,Jegham, Nafaa,Ben Hassine, Béchir
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experimental part
p. 1278 - 1283
(2011/12/04)
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- MITOTIC KINESIN INHIBITORS
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The present invention relates to dihydropyrazole compounds that are useful for treating cellular proliferative diseases, for treating disorders associated with KSP kinesin activity, and for inhibiting KSP kinesin. The invention also related to compositions which comprise these compounds, and methods of using them to treat cancer in mammals.
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Page/Page column 51-52
(2008/06/13)
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- Privileged structure based ligands for melanocortin-4 receptors-Aliphatic piperazine derivatives
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Aliphatic carbocyclic replacement of the benzyl group of compound 1 yielded compounds with high affinity for the melanocortin-4 receptor (MC4R). Compounds with a cyclohexyl group showed a consistent high affinity, while different polar groups with less basicity were good replacements for the original diethyl amines. Substitution of the polar group found in these privileged structures with an aliphatic moiety produced compounds with high affinity for MC4R.
- Briner, Karin,Collado, Iván,Fisher, Matthew J.,García-Paredes, Cristina,Husain, Saba,Kuklish, Steven L.,Mateo, Ana I.,O'Brien, Thomas P.,Ornstein, Paul L.,Zgombick, John,de Frutos, óscar
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p. 3449 - 3453
(2007/10/03)
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- α-amino acid phenolic ester derivatives: Novel water-soluble general anesthetic agents which allosterically modulate gabaa receptors
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In the search for a novel water-soluble general anesthetic agent the activity of an α-amino acid phenolic ester lead, identified from patent literature, was markedly improved. In addition to improving in vivo activity in mice, good in vitro activity at GABAA receptors was also conferred. Within the series of compounds good enantioselectivity for both in vitro and in vivo activity was found, supporting a protein-mediated mechanism of action for anesthesia involving allosteric modulation of GABAA receptors. α-Amino acid phenolic ester 19, as the hydrobromide salt Org 25435, was selected for clinical evaluation since it retained the best overall anesthetic profile coupled with improved stability and water solubility. In the clinic it proved to be an effective intravenous anesthetic in man with rapid onset of and recovery from anesthesia at doses of 3 and 4 mg/kg.
- Anderson,Belelli,Bennett,Buchanan,Casula,Cooke,Feilden,Gemmell,Hamilton,Hutchinson,Lambert,Maidment,McGuire,McPhail,Miller,Muntoni,Peters,Sansbury,Stevenson,Sundaramt
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p. 3582 - 3591
(2007/10/03)
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- Process research and development of L-alanyl-L-glutamine, a component of parenteral nutrition
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A large-scale manufacturing method of L-alanyl-L-glutamine used for a component of parenteral nutrition has been studied. The method consisted of a reaction of D-2-chloro- or D-2-bromopropionic acid with thionyl chloride and Schotten-Baumann reaction with L-glutamine followed by ammonolysis reaction. The intermediate D-2-chloropropionyl-L-glutamine was found to be more stable than its bromo analogue. In the ammonolysis reaction, the former intermediate needed a higher reaction temperature, but the by-products produced had little effect on the quality of the final product. The structures of the by-products were conjectured mainly by mass spectrometry and they were removed by anion resin treatment and recrystallization.
- Sano, Takahiro,Sugaya, Toru,Inoue, Kunimi,Mizutaki, Sho-Ichi,Ono, Yasuyuki,Kasai, Masaji
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p. 147 - 152
(2013/09/07)
-
- Dynamic enzymatic resolution of thioesters
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A detailed investigation of several issues related to the enzymatic resolution of thioesters under conditions of continuous racemization of substrate was conducted. The kinetic acidity of the α-protons of a series of α-substituted propionate thioesters was studied. It was found that the rate of α-proton exchange could be enhanced as much as 20-fold by variation of the thiol moiety, increasing the range of compounds to which enzymatic dynamic resolution may be applied. The relative rates of hydrolysis of ethyl butyrate and ethyl thiobutyrate by several enzymes commonly used in enzymatic resolution were determined. All of the enzymes studied exhibited similar rates of thioester and oxoester hydrolysis except for the esterase from pig liver, which showed very low activity in thioester hydrolysis. Dynamic resolution of the propargyl and trifluoroethyl thioesters of α- phenylpropionate was conducted using subtilisin Carlsberg as a catalyst. These examples demonstrated that enzymatic dynamic resolution can be applied even when the rate of α-proton exchange and the enantioselectivity of the enzyme are fairly low. A dynamic enzymatic transesterification procedure was demonstrated in the resolution of the trifluoroethyl thioester of α-(2,4- dichlorophenoxy)propionate, and product was obtained in 93% ee. This work helps expand and define the scope of enzymatic dynamic resolution of thioesters.
- Um, Pil-Je,Drueckhammer, Dale G.
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p. 5605 - 5610
(2007/10/03)
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- Stereoselective synthesis of α-substituted ulosonic acids by magnesio-Reformatsky reactions
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A new method of homologation of aldonolactones allowing the incorporation of propionate units with excellent chemo- and stereoselectivity is performed by the magnesium-graphite mediated reaction between Oppolzer sultam derived α-halogenated amides and an aldonolactone.
- Csuk, Rene,Schroeder, Christina,Krieger, Claus
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p. 12947 - 12960
(2007/10/03)
-
- PTC sulfanylation of some carboxylic acids derivatives activated by α-sulfonyl or α-sulfinyl group, in solid-liquid system
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The sulfanylation of α-sulfonyl substituted lactone and thioesters and α-sulfinyl-substituted esters and thioesters, employing solid K2CO3, S-methyl methanethiosulfonate and TEBA, is reported. The results are compared with those in the homogeneous phase and in the non-catalytic two-phase system.
- Wladislaw, Blanka,Marzorati, Liliana,Donnici, Claudio L.,Biaggio, Francisco C.,Neves, Regina M. A.,Claro Jr., Nelson F.
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p. 197 - 208
(2007/10/03)
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- Presynaptic cholinergic modulators as potent cognition enhancers and analgesic drugs. 2. 2-Phenoxy-, 2-(phenylthio)-, and 2-(phenylamino)alkanoic acid esters
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Further modifications of the leads ((R)-(+)-hyoscyamine and (p- chlorophenyl)propionic acid α-tropanyl ester), which show analgesic and nootropic activities as a consequence of increased central presynaptic ACh release, are reported. 2-Phenoxy- and 2-(phenylthio)alkanoic acid esters showed the best results. Several members of these classes possess analgesic properties which are comparable to that of morphine and at the same time are able to reverse dicyclomine-induced amnesia. Confirmation was found that the mechanism of action is due to an increase in ACh release at central muscarinic synapses and that both auto- and heteroreceptors controlling ACh release are very likely involved. According to the results obtained with (R)- (+)-hyoscyamine, analgesic activity is stereochemistry dependent, since the R-(+)-enantiomers are always more efficacious than the corresponding S-(-)- ones. On the basis of their potency and acute toxicity, compounds (±)-28 (SM21) and (±)-42 (SM32) were selected for further study.
- Gualtieri,Bottalico,Calandrella,Dei,Giovannoni,Mealli,Romanelli,Scapecchi,Teodori,Galeotti,Ghelardini,Giotti,Bartolini
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p. 1712 - 1719
(2007/10/02)
-
- Chemistry of Novel Compounds with Multifunctional Carbon Structure. 9. Molecular Design, Synthetic Studies, and NMR Investigation of Several Efficient Chiral Derivatizing Reagents which Give Very Large (19)F NMR Δδ Values in Enantiomeric Excess Determination
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In order to develop efficient ee-determining reagents potentially superior to MTPA (1), some multifunctional compounds 2-5 were rationally designed.From NMR investigations of the analogous diastereomeric derivatives it was found that the chemical shift differences for each pair of diastereomers (Δδ values) for CFPA derivatives 5d-f were approximately five times greater in (19)F NMR spectra and two times greater in 1H NMR spectra than those of 1d-f.Synthesis of the optically pure CFPA, (-)-5a nd (+)-5a, was achieved by nitrosation of each diasteromer of the optically active N-(1-phenylethyl)amides, 5fM and 5fL, followed by thermal decomposition.Various derivatives were prepared by the condensation of 5b and 1b with alcohol and amine nucleophiles, and both ΔδF and ΔδH values were obtained for each compound.The CFPA derivatives 5d-m have proven to be significantly superior for ee determinations when compared to the corresponding MTPA derivatives 1d-m, particularly in compounds having remotely disposed chiral centers.
- Takeuchi, Yoshio,Itoh, Noriaki,Satoh, Toshihiro,Koizumi, Toru,Yamaguchi, Kentaro
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p. 1812 - 1820
(2007/10/02)
-
- Synthesis and study of new α-haloacid ferroelectric liquid crystal derivatives. MM2 approach to the molecular structure-ferroelectric activity relationship
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In order to understand the structural factors that influence ferroelectric properties, three new series (F, Cl, and Br) of chiral naphthalene-ring derived compounds were synthesized, and their ferroelectric properties [spontaneous polarization (Ps) and response time (τ)] were evaluated in the pure compound. The chiral tails are α-halo acids derived from L-α-amino acids: L-α-alanine (1), L-leucine (2), L-isoleucine (3), and L-valine (4), with a fluorine, chlorine, or bromine atom in the chiral center. The highest Ps values were obtained for compounds containing a fluorine or chlorine atom in their asymmetric center and with chiral tail derived from L-isoleucine (3) (F-3, 102 nC/cm2; Cl-3, 100 nC/cm2). The steric requirements of the halogen atom and the bulky alkyl group in the asymmetric center determine the most stable conformations of these chiral tails, which have been studied by molecular mechanic empirical calculations, MM2. MM2 calculations prove to be a successful tool for understanding how the structure of the lateral chiral tail affects molecular arrangement and, as a consequence, the ferroelectric properties of the materials.
- Sierra,Serrano,Ros,Ezcurra,Zubía
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p. 7645 - 7651
(2007/10/02)
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- Synthesis of chrysogine, a metabolite of Penicillium chrysogenum and some related 2-substituted 4-(3H)-quinazolinones
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Syntheses of both enantiomers of chrysogine, 2-(α-hydroxyethyl)-4(3H)-quinazolinone, 1 from 2-ammobenzamide are reported. Thus reaction of 2-aminobenzamide and optically active α-acetoxypropionyl chloride gave 9, which upon saponification and cyclization induced by aqueous sodium carbonate at room temperature gave chrysogine. The enantiomeric purity of 1 was determined by NMR. Inversion of (-)-(S)-1, using the Mitsunobo reaction, gave (+)-(R)-1. Reduction of 2-acetyl-4(3H)-qumazolinone 2 with baker's yeast gave the S-enantiomer of 1. The cyclization method used could be extended and a number of 2-(a-hydroxy)alkyl-4-(3H)-quinazolinones are also reported.
- Bergman, Jan,Brynolf, Anna
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p. 1295 - 1310
(2007/10/02)
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- Synthesis and Reaction of Optically Active Morpholinones
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The reactions of variously substituted chiral morpholin-2-and-3-ones chemoselectively synthesized from chiral amino acids and lactic acid as the chiral source are described.
- Kashima, Choji,Harada, Kazuo
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p. 1521 - 1526
(2007/10/02)
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- Herbicidal aryl triazolinones
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Herbicidal aryl triazolinones include the compounds of the formula STR1 where X is preferably halogen such as fluorine, Y is preferably halogen such as chlorine, R1 is preferably methyl, R2 is preferably CHF2, R3 is preferably CH(CH3), and STR2 is --NH2 or the residue of a primary or secondary amine or of a sulfonamide.
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- Catalytic Asymmetric Cyclization of Some Bromohydrins with Chiral Cobalt Complex
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Asymmetric cyclization of a variety of bromohydrins with base was examined in the presence of an optically active cobalt(salen) type complex.Optically active oxiranes of modest optical purities were obtained. erythro-3-Bromo-2-butanol and threo-3-bromo-2-butanol were cyclized similarly, and only trans-2,3-dimethyloxirane and cis-2,3-dimethyloxirane were obtained, respectively, indicating that the cyclization of bromohydrin proceeds by complete SN2 type reaction.
- Takeichi, Tsutomu,Takakura, Teruo,Ishimori, Michihiro,Tsuruta, Teiji
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p. 603 - 605
(2007/10/02)
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- Process for preparing naproxen
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Process for preparing Naproxen via a sequence of stereospecific reactions which comprises: condensation of 1-chloro-2-methoxy-naphthalene with a (S)-2-halo-propionyl halide according to the Friedel-Crafts reaction, ketalization of the thus obtained (S)-2-halo-1-(5'-chloro-6'-methoxy-2'-naphthyl)-propan-1-one, rearrangement of said ketal to afford an ester, hydrolysis of the ester and removal of the chlorine atom in 5-position by hydrogenolysis. New (S) 2-halo-1-(5'-chloro-6'-methoxy-2'-naphthyl)-propan-1-ones.
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- The Determination of Small Amounts of Enantiomeric Impurities in α-Halo Carboxylic Acids
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The accurate determination of the enantiomeric composition of α-halo carboxylic acids is reported.Such data are of importance in the synthesis of chiral compounds and in mechanistic studies involving the title compounds.
- Watabe, K.,Chang, S.-C.,Gil-Av, E.,Koppenhoefer, B.
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p. 225 - 228
(2007/10/02)
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- Preparation and Properties of Substituted 6&β-Vinylpenicillanic Acids
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Routes to the title compounds are described, either using the selective addition of thiols to the known 6-allylidenepenicillanic acids or by the conjugate addition of Grignard derivatives, derived from 6,6-dibromopenicillanates, to substituted acrylates and acrylamides, followed by stereoselective reduction of the remaining 6-bromo-group to produce the 6β-substituted penicillanates.The 6β-derivatives containing the acryloyl side-chain were relatively unstable and readily underwent intramolecular rearrangement to the corresponding thiazepinones.
- Foulds, Christopher D.,Jaxa-Chamiec, Albert A.,O'Sullivan, Anthony C.,Sammes, Peter G.
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- 1,3-Dipolar Character of Six-membered Aromatic Rings. Part 52. 2?+8? Cycloaddition Reactions of 1-Substituted 3-Oxidopyridinium Betaines
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Dichloroketen and a series of aryl(bromo)ketens react with various 1-substituted 3-oxidopyridiniums to give novel bicyclic compounds by addition across the C(4)-O and the C(2)-O positions.Frontier-MO theory is used to rationalise the orientation of these cycloadditions.Acid-catalysed hydrolysis of the C(2)-O adducts (9) yielded 3-hydroxy-2-benzylpyridines.
- Katritzky, Alan R.,Cutler, Alan T.,Dennis, Nicolas,Sabongi, Gebran J.,Rahimi-Rastgoo, Soheila,et al.
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p. 1176 - 1184
(2007/10/02)
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