72580-53-1Relevant articles and documents
Zeolite 4A supported CdS/g-C3N4 type-II heterojunction: A novel visible-light-active ternary nanocomposite for potential photocatalytic degradation of cefoperazone
AttariKhasraghi, Naime,Behnajady, Mohammad A.,Mehrizad, Ali,Modirshahla, Nasser,Zare, Karim
, (2021/09/15)
The CdS/g-C3N4 heterojunction photocatalyst supported on 4A zeolite was successfully synthesized using a simple chemical precipitation method. The physicochemical characteristics of the as-prepared ternary composite were assessed using X-Ray diffraction (XRD), field emission- scanning electron microscopy (FE-SEM), energy dispersive X-Ray (EDX), transmission electron microscopy (TEM), N2 adsorption–desorption, differential reflectance spectroscopy (UV–Vis-DRS), and photoluminescence (PL) techniques. The results confirmed the successful synthesis of the CdS/g-C3N4/4AZ nanocomposite and introduction of the CdS and g-C3N4 on the substrate of 4A zeolite. Cefoperazone (CFP) antibiotic was tested as the model pollutant to assess the photocatalytic performance of the synthesized nanocomposite under visible light irradiation. The response surface methodology (RSM) and artificial neural network (ANN) showed desirable reasonability for the prediction of the CFP degradation efficiency. More than 93% of CFP with a concentration of 17 mg L-1 degraded in the presence of the 0.4 g L-1 of the catalyst at pH of 9 after 80 min treatment time (RSM-based optimization results). The pH of the solution, irradiation time, catalyst dosage, and the initial concentration of the CFP affected degradation efficiency with a percentage impact of 37, 29, 19, and 15 %, respectively (ANN-based modeling results). The addition of 1 mM of isopropanol, benzoquinone, and sodium oxalate reduced the CFP degradation efficiency from 93.23% to 85.18, 41.16, and 32.47%, respectively, proving the decisive role of the °O2– and h+ in the photodegradation process. The kinetic studies indicated the following of the process from the Langmuir-Hinshelwood's pseudo-first-order model (kapp = 3.71 × 10-2 min?1). The structure of the identified by-products using GC-MS analysis confirmed that CFP mainly decomposed through the cleavage of C-S, C-N, and N-N bonds. Moreover, the formation of the aliphatic compounds and carboxylic acids as by-products confirmed nearly complete mineralization of the CFP to non-toxic products.
Preparation method of chiral 3-substituted pyrrolidine derivative
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Paragraph 0058-0061, (2020/11/01)
The invention provides a preparation method of a chiral 3-substituted pyrrolidine derivative. The preparation method comprises an intermediate preparation step, a diastereomer mixture preparation step, a chiral separation step and a chiral 3-substituted pyrrolidine derivative synthesis step. According to the invention, through catalytic asymmetric kinetic resolution, a mixture of two diastereoisomers is efficiently converted into a diastereoisomer with a certain single configuration, chiral separation is realized, a key intermediate is obtained with high yield, and a series of chiral 3-substituted pyrrolidine derivatives are synthesized. The whole reaction route is mild in reaction condition, simple and convenient to operate, high in resolution efficiency, high in atom economy, low in costand suitable for industrial scale production.
Design of novel HIV-1 protease inhibitors incorporating isophthalamide-derived P2-P3 ligands: Synthesis, biological evaluation and X-ray structural studies of inhibitor-HIV-1 protease complex
Ghosh, Arun K.,Brindisi, Margherita,Nyalapatla, Prasanth R.,Takayama, Jun,Ella-Menye, Jean-Rene,Yashchuk, Sofiya,Agniswamy, Johnson,Wang, Yuan-Fang,Aoki, Manabu,Amano, Masayuki,Weber, Irene T.,Mitsuya, Hiroaki
, p. 5114 - 5127 (2017/09/26)
Based upon molecular insights from the X-ray structures of inhibitor-bound HIV-1 protease complexes, we have designed a series of isophthalamide-derived inhibitors incorporating substituted pyrrolidines, piperidines and thiazolidines as P2-P3 ligands for specific interactions in the S2-S3 extended site. Compound 4b has shown an enzyme Ki of 0.025 nM and antiviral IC50 of 69 nM. An X-ray crystal structure of inhibitor 4b-HIV-1 protease complex was determined at 1.33 ? resolution. We have also determined X-ray structure of 3b-bound HIV-1 protease at 1.27 ? resolution. These structures revealed important molecular insight into the inhibitor–HIV-1 protease interactions in the active site.
Highly selective asymmetric Rh-catalyzed hydroformylation of heterocyclic olefins
Chikkali, Samir H.,Bellini, Rosalba,De Bruin, Bas,Van Der Vlugt, Jarl Ivar,Reek, Joost N. H.
supporting information; experimental part, p. 6607 - 6616 (2012/06/15)
A small family of new chiral hybrid, diphosphorus ligands, consisting of phosphine-phosphoramidites L1 and L2 and phosphine-phosphonites L3a-c, was synthesized for the application in Rh-catalyzed asymmetric hydroformylation of heterocyclic olefins. High-pressure (HP)-NMR and HP-IR spectroscopy under 5-10 bar of syngas has been employed to characterize the corresponding catalyst resting state with each ligand. Indole-based ligands L1 and L2 led to selective ea coordination, while the xanthene derived system L3c gave predominant ee coordination. Application of the small bite-angle ligands L1 and L2 in the highly selective asymmetric hydroformylation (AHF) of the challenging substrate 2,3-dihydrofuran (1) yielded the 2-carbaldehyde (3) as the major regioisomer in up to 68% yield (with ligand L2) along with good ees of up to 62%. This is the first example in which the asymmetric hydroformylation of 1 is both regio- and enantioselective for isomer 3. Interestingly, use of ligand L3c in the same reaction completely changed the regioselectivity to 3-carbaldehyde (4) with a remarkably high enantioselectivity of 91%. Ligand L3c also performs very well in the Rh-catalyzed asymmetric hydroformylation of other heterocyclic olefins. Highly enantioselective conversion of the notoriously difficult substrate 2,5-dihydrofuran (2) is achieved using the same catalyst, with up to 91% ee, concomitant with complete regioselectivity to the 3-carbaldehyde product (4) under mild reaction conditions. Interestingly, the Rh-catalyst derived from L3c is thus able to produce both enantiomers of 3-carbaldehyde 4, simply by changing the substrate from 1 to 2. Furthermore, 85% ee was obtained in the hydroformylation of N-acetyl-3-pyrroline (5) with exceptionally high regioselectivities for 3-carbaldehyde 8Ac (>99%). Similarly, an ee of 86% for derivative 8Boc was accomplished using the same catalyst system in the AHF of N-(tert-butoxycarbonyl)-3-pyrroline (6). These results represent the highest ees reported to date in the AHF of dihydrofurans (1, 2) and 3-pyrrolines (5, 6).
A rapid and convenient synthesis of β-proline
Blanchet, Jér?me,Pouliquen, Mickael,Lasne, Marie-Claire,Rouden, Jacques
, p. 5727 - 5730 (2008/02/09)
A short, reliable, and cheap synthesis of both enantiomers of β-proline, an efficient organocatalyst and an important building block in medicinal chemistry, has been developed in four steps (overall yield: 72%) from the diasteromeric adducts of methyl itaconate and (R)-α-methylbenzylamine. The key step involves the chemoselective reduction of a lactam group in the presence of a benzyl ester.
TRANS-3,5-DISUBSTITUTEDPYRROLIDINE: ORGANOCATALYST FOR anti-MANNICH REACTIONS
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Page/Page column 26, (2010/11/27)
A compound of Formula I is disclosed, in which R is a substituent containing a hydrogen bond-forming atom within three atoms from the ring carbon to which the substituent is bonded; X is CH2, O, S or NR1, wherein R1 is a hydrocarbyl group or an amino-protecting group having one to about 18 carbon atoms; R2 is hydrido or a hydrocarbyl group containing one to about twelve carbon atoms; and R3 is hydrido or methyl, but both R2 and R3 are not hydrido when X is CH2 A molecule of Formula I and those in which R2 and R3 can both be hydrido (Formula X) functions as a catalyst in a Mannich reaction to asymmetrically form β-aminoaldehyde or β-aminoketone diastereomeric products having two chiral centers on adjacent carbon atoms and in which the anti-diastereomers are in excess over the syn-diastereomers. Methods for carrying out those syntheses are also disclosed.
3-Pyrrolidinecarboxylic acid for direct catalytic asymmetric anti-Mannich-type reactions of unmodified ketones
Zhang, Haile,Mifsud, Maria,Tanaka, Fujie,Barbas III, Carlos F.
, p. 9630 - 9631 (2007/10/03)
We report the development of direct catalytic, enantioselective, anti-selective Mannich-type reactions between unmodified ketones and α-imino esters under mild conditions. The reactions were performed using 5-10 mol % of (R)-3-pyrrolidinecarboxylic or (R)-β-proline as catalyst in an environmentally benign solvent, 2-PrOH, at room temperature. The anti-Mannich products were obtained in good yields with high diastereo- and enantioselectivities (up to anti/syn >99:1, 99% ee). While (3R,5R)-5-methyl-3-pyrrolidinecarboxylic acid is an excellent catalyst for the anti-Mannich-type reactions of aldehydes, it did not efficiently catalyze the corresponding Mannich-type reactions of ketones; (R)-3-pyrrolidinecarboxylic acid did efficiently catalyze the Mannich-type reactions of ketones. (S)-Proline or (S)-2-pyrrolidinecarboxylic acid has been reported to catalyze the Mannich-type reactions of ketones to afford the syn-products. Thus, the position of the carboxylic acid group on the pyrrolidine ring directs the stereoselection of the catalyzed reaction, providing either syn- or anti-Mannich products. Copyright
Stability against enzymatic hydrolysis of endomorphin-1 analogues containing β-proline
Cardillo, Giuliana,Gentilucci, Luca,Tolomelli, Alessandra,Calienni, Maria,Qasem, Ahmed R.,Spampinato, Santi
, p. 1498 - 1502 (2007/10/03)
The enantiomer of endomorphin-1 (Tyr-Pro-Trp-PheNH2) and the analogues containing (S)-or (R)-β-proline have been synthesized, and their affinities towards μ-opioid receptors have been measured. As expected, the incubations of the different peptides with some commercially available enzymes showed that the presence of D-residues gave strong resistance towards digestion. The presence of β-proline alone is sufficient to confer good resistance against the hydrolysis of the biologically strategic Pro-Trp bond.
Synthesis and binding activity of endomorphin-1 analogues β-amino acids
Cardillo, Giuliana,Gentilucci, Luca,Melchiorre, Paolo,Spampinato, Santi
, p. 2755 - 2758 (2007/10/03)
Endomorphin-1 (Tyr-Pro-Trp-PheNH2) has been proposed as the most potent endogenous ligand of the μ-opioid receptors. In this paper, we describe the synthesis of some endomorphin-1 based tetrapeptides in which a residue of the sequence Tyr-Pro-Trp-PheNH2 is replaced by the corresponding β-isomer. These novel peptides showed different affinities for the opioid receptors labeled with [3H]-DAMGO in rat brain membranes, depending on the β-amino acid. In particular, the tetrapeptide containing β-Pro (Tyr-β-(R)-Pro-Trp-PheNH2) displayed a higher affinity than endogenous endomorphin-1, as revealed by their K(i) values (0.33 and 11.1 nM, respectively). (C) 2000 Elsevier Science Ltd.
A practical ex-chiral-pool synthesis of β-proline and homo-β-proline
Thomas, Christoph,Orecher, Florian,Gmeiner, Peter
, p. 1491 - 1496 (2007/10/03)
Starting from aspartic acid an efficient synthesis of enantiomerically pure β-proline and homo-β-proline is described. The key step of the synthesis includes formation of the 1,4-biselectrophile 6, followed by rearrangement via the aziridinium intermediate 7 and ring closure to give the pyrrolidinium salt 9a which can serve as a common precursor for both target compounds.
