- Synthesis, spectroscopic characterization, and antifungal activity of some mixed ligand complexes of Zn(II), Cd(II), and Hg(II)
-
A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with citronellal thiosemicarbazone [3,7-dimethyl-6-octene-1-a1 thiosemicarbazone (LH)] and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal(II) chloride with ligands citronellal thiosemicarbazone (DOTSC) and N-phthaloyl glycine [1,3-dihydro-1,3-dioxo-2H-isoindole-2-acetic acid (A1H)] or N-phthaloyl alanine [1,3-dihydro-1,3-dioxo-(methyl)-2H-isoindole-2-acetic acid (A2H)] in 1:1:1 molar ratio in dry refluxing ethanol. All the complexes have been characterized by elemental analyses, molar conductance measurement, molecular weight measurement, IR, and multinuclear NMR (1H and 13C{1H}) spectral studies. IR, 1H, and 13C{1H} NMR spectral studies suggest the involvement of azomethine-N, thiol-S atoms of the thiosemicarbazone moiety and both carboxylate-O of N-phthaloyl amino acid moiety in coordination with central metal(II) ion, and four coordinated geometries have been assigned to these complexes. The free ligands and metal complexes have been screened for their antifungal activity against two fungal strains, Fusarium moniliformae and Macrophomina phaseolina, using the the radial growth method. The results of antifungal activity show that metal complexes show enhanced higher activity than the free ligands. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Sharma, Renu,Nagar, Meena
-
-
Read Online
- Synthesis, structural, and antibacterial studies of some mixed ligand complexes of Zn(II), Cd(II), and Hg(II) derived from citral thiosemicarbazone and N-phthaloyl amino acids
-
A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with cis-3,7-dimethyl-2,6-octadienthiosemicarbazone (CDOTSC; LH) and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal dichloride with ligands CDOTSC and N-phthaloyl derivative of DL-glycine (A1H), L-alanine (A2H), or L-valine (A3H) in a 1:1:1 molar ratio in dry refluxing ethanol. All the isolated complexes have the general composition [M(L)(A)]. The plausible structure of these newly synthesized complexes has been proposed on the basis of elemental analyses, molar conductances, molecular weight measurement, and various spectral (IR, 1H NMR, and 13C NMR) studies, and four coordinated geometries have been assigned to these complexes. All the complexes and ligands have been screened for their antibacterial activity. Copyright Taylor & Francis Group, LLC.
- Sharma, Renu,Nagar, Meena
-
-
Read Online
- Dynamic kinetic resolution utilizing 2-oxoimidazolidine-4-carboxylate as a chiral auxiliary: Stereoselective synthesis of α-amino acids by Gabriel reaction
-
A Highly stereoselective Gabriel reaction via dynamic kinetic resolution utilizing 2-oxoimidazolidine-4-carboxylate as a chiral auxiliary was exploited. The reaction of tert-butyl (4S)-1-methyl-3-(2-bromopropionyl)-2- oxoimidazolidine-4-carboxylate (2a) w
- Kubo, Akira,Kubota, Hitoshi,Takahashi, Masami,Nunami, Ken-Ichi
-
-
Read Online
- Synthesis of new amides based on N-Phthaloyl-α-Amino Acids
-
N-phthaloyl derivatives of aliphatic α-amino acids were synthesized using phthalanhydride under standard conditions. The optimization reaction carried out by the thermal method to obtain the amides of these N-phthaloyl amino acids resulted in transimitted rather than amidation. The target amides of N-phthaloyl-α-amino acids were obtained by acylation of the amine with the corresponding acid chloroanhydrides in dichloromethane. These results were compared with the results of a similar acylation in a non-polar solvent (benzene). The dependence of the direction of the reaction on the duration of the acylation and the amount of amine used was established. The conditions for the formation of the corresponding N-phthaloyl-α-amino acid amides and asymmetric phthalic acid diamides were found. It is noteworthy that the formation of diamides is directly proportional to the equivalent amount of amine and the duration of the reaction, which makes it possible to purposefully control the synthesis in one reactor.
- Tukhtaev,Yusupov,Vinogradova
-
p. 3049 - 3058
(2021/05/28)
-
- AMINO ACID DERIVATIVES FOR THE TREATMENT OF INFLAMMATORY DISEASES
-
The present disclosure provides certain amino acid derivatives that inhibit NF-kB activation and are therefore useful for the treatment of inflammatory diseases. Also provided are pharmaceutical compositions containing such compounds and processes for preparing such compounds.
- -
-
Page/Page column 31
(2020/08/13)
-
- Synthesis of novel phthalimido oxime pseudoesters and evaluation of their cytotoxicity
-
A series of novel optically pure oxime pseudoesters derivatives were synthesized by the reaction of substitute keto oximes with various N-substituted α-amino acids chlorides in the presence of triethylamine and dichloromethane at 0 °C, and their structures were characterized by IR and 1D-NMR methods. The synthesized compounds were tested for their ability to inhibit the proliferation of human colon cancer cells and human epithelial cells. Some of them were revealed to have a significant cytotoxic effect.
- Mehrez, Asma,Chakroun, Ibtissem,Mtat, Dalila,Mansour, Hédi Ben,Touati, Ridha
-
-
- 1-Aminopyridinium Ylides as Monodentate Directing Groups for sp3 C-H Bond Functionalization
-
1-Aminopyridinium ylides are efficient directing groups for palladium-catalyzed β-arylation and alkylation of sp3 C-H bonds in carboxylic acid derivatives. The efficiency of these directing groups depends on the substitution at the pyridine moiety. The unsubstituted pyridine-derived ylides allow functionalization of primary C-H bonds, while methylene groups are unreactive in the absence of external ligands. 4-Pyrrolidinopyridine-containing ylides are capable of C-H functionalization in acyclic methylene groups in the absence of external ligands, thus rivaling the efficiency of the aminoquinoline directing group. Preliminary mechanistic studies have been performed. A cyclopalladated intermediate has been isolated and characterized by X-ray crystallography, and its reactivity was studied.
- Le, Ky Khac Anh,Nguyen, Hanh,Daugulis, Olafs
-
supporting information
p. 14728 - 14735
(2019/10/11)
-
- Amino acid chiral ligand containing bidentate coordination group, chiral catalyst, and corresponding preparation methods and applications thereof
-
The present invention relates to an amino acid chiral ligand containing a bidentate coordination group, a chiral catalyst, and corresponding preparation methods and applications thereof. The chiral ligand is prepared from a cheap and easily available amino acid, and the development of the chiral ligand can improve the diversity of the chiral ligand. The chiral Ir (III) catalyst is simply and efficiently prepared from the chiral ligand only through a one-step reaction. The chiral Ir (III) catalyst is characterized in that a bidentate guiding group is introduced to an amino acid framework to change the original coordination mode of the amino acid and Ir in order to enhance the chiral control ability of the amino acid to the Ir(III) catalyst. The chiral Ir(III) catalyst is designed and synthesized for the first time, and the selectivity reaches up to 99% ee when the catalyst is successfully applied to the high-efficiency asymmetric synthesis of chiral gamma-cyclolactam, so the catalyst has superior stereo control ability.
- -
-
Paragraph 0072
(2019/10/02)
-
- Discovery of a novel dipeptidyl boronic acid proteasome inhibitor for the treatment of multiple myeloma and triple-negative breast cancer
-
A series of novel dipeptidyl boronic acid compounds were designed, synthesized and biologically investigated for the inhibition of the β5 subunit of 20S proteasome and several compounds showed high activities with IC50 values of less than 10 nM. Some of these compounds potently inhibited the multiple myeloma (MM) cancer cell lines with IC50 values of less than 10 nM. It was reported that the inhibition of both β2 and β5 subunits strongly increased the cytotoxicity of proteasome inhibitors in solid tumor cells, so some of the compounds were evaluated for the inhibition of the β2 subunit and the solid tumor triple-negative breast cancer cell line MDA-MB-231. The results showed that three compounds were active for both the β2 subunit and the triple-negative breast cancer cell line MDA-MB-231. The in vivo pharmacokinetic results showed that compound 8t had good biological parameters for both ig and iv administrations. An in vivo pharmacodynamic experiment showed that compound 8t inhibited the β5 subunit in whole blood more greatly than the marketed MLN9708 with the same dose at different time periods. A pathological analysis indicated that the injection of compound 8t in the tumor of a triple-negative breast cancer xenograft mice model led to tumor cell necrosis, nucleus condensation, deep staining, cell fragmentation, dissolution and neutrophil infiltration compared with the control group. The data in hand showed that compound 8t might be an effective candidate for the treatment of both MM and triple-negative breast cancer.
- Lei, Meng,Feng, Huayun,Bai, Enhe,Zhou, Hui,Wang, Jia,Qin, Yanru,Zhang, Haoyang,Wang, Xueyuan,Liu, Zhaogang,Hai, Ou,Liu, Jia,Zhu, Yongqiang
-
supporting information
p. 683 - 691
(2019/01/24)
-
- Synthesis and application of peptide borate compounds
-
The invention belongs to the field of drug synthesis, and specifically relates to a series of novel peptide borate compounds or pharmaceutical salts thereof, and a preparation method and pharmaceutical application thereof. The structure of the peptide borate compounds or the pharmaceutical salts thereof is as shown in a formula I which is described in the specification. The compounds of the invention can be used for preparing proteasome inhibitors, and thus can be further used for treating solid tumors and blood tumors.
- -
-
Paragraph 0111; 0112; 0115; 0116
(2019/12/25)
-
- Silver-Catalyzed Efficient Synthesis of Oxindoles and Pyrroloindolines via α-Aminoalkylation of N-Arylacrylamides with Amino Acid Derivatives
-
α-Aminoalkylation of N-arylacrylamides with amino acid derivatives was achieved by silver-catalysis in moderate to high yields. The reaction provides an efficient strategy for the synthesis of functionalized oxindoles, and is suitable for a wide range of N-arylacrylamides and amino acids, both of which are inexpensive and readily available. The oxindoles obtained were readily transformed into densely functionalized pyrroloindolines by deprotection and cyclization in one pot.
- Kanyiva, Kyalo Stephen,Makino, Sohei,Shibata, Takanori
-
supporting information
p. 496 - 499
(2018/03/06)
-
- Antiplasmodial activity of hydroxyethylamine analogs: Synthesis, biological activity and structure activity relationship of plasmepsin inhibitors
-
Malaria, particularly in endemic countries remains a threat to the human health and is the leading the cause of mortality in the tropical and sub-tropical areas. Herein, we explored new C2 symmetric hydroxyethylamine analogs as the potential inhibitors of Plasmodium falciparum (P. falciparum; 3D7) in in-vitro cultures. All the listed compounds were also evaluated against crucial drug targets, plasmepsin II (Plm II) and IV (Plm IV), enzymes found in the digestive vacuole of the P. falciparum. Analog 10f showed inhibitory activities against both the enzymes Plm II and Plm IV (Ki, 1.93 ± 0.29 μM for Plm II; Ki, 1.99 ± 0.05 μM for Plm IV). Among all these analogs, compounds 10g selectively inhibited the activity of Plm IV (Ki, 0.84 ± 0.08 μM). In the in vitro screening assay, the growth inhibition of P. falciparum by both the analogs (IC50, 2.27 ± 0.95 μM for 10f; IC50, 3.11 ± 0.65 μM for 10g) displayed marked killing effect. A significant growth inhibition of the P. falciparum was displayed by analog 12c with IC50 value of 1.35 ± 0.85 μM, however, it did not show inhibitory activity against either Plms. The hemolytic assay suggested that the active compounds selectively inhibit the growth of the parasite. Further, potent analogs (10f and 12c) were evaluated for their cytotoxicity towards mammalian HepG2 and vero cells. The selectivity index (SI) values were noticed greater than 10 for both the analogs that suggested their poor toxicity. The present study indicates these analogs as putative lead structures and could serve as crucial for the development of new drug molecules.
- Kumar Singh, Amit,Rajendran, Vinoth,Singh, Snigdha,Kumar, Prashant,Kumar, Yogesh,Singh, Archana,Miller, Whelton,Potemkin, Vladimir,Poonam,Grishina, Maria,Gupta, Nikesh,Kempaiah, Prakasha,Durvasula, Ravi,Singh, Brajendra K.,Dunn, Ben M.,Rathi, Brijesh
-
p. 3837 - 3844
(2018/07/13)
-
- A Simple Aliphatic Diamine Auxiliary for Palladium-Catalyzed Arylation of Unactivated β-C(sp3)-H Bonds
-
Palladium-catalyzed β-C(sp3)-H arylation of aliphatic acid derivatives was achieved by means of 2-dimethylaminoethylamine auxiliary as a directing group. The β-C(sp3)-H arylation reactions with aryl and heteroaryl iodides efficiently afforded the corresponding arylated hydrocinnamic acid derivatives. Direct β-C(sp3)-H alkynylation, and arene C?H arylation and alkynylation were also realized under the same or slightly modified conditions. The aliphatic diamine auxiliary in the products could be readily removed by methanol in the presence of BF3 ? OEt2. In comparison with the widely used bidentate nitrogen-containing directing groups, 2-dimethylaminoethylamine is a simple, cheap, readily available and removable, and atom-economical directing group for C?H functionalization. (Figure presented.).
- Lou, Jiang,Wang, Quannan,He, Yuan,Yu, Zhengkun
-
supporting information
p. 4571 - 4584
(2018/10/25)
-
- Chiral sensors for determining the absolute configurations of α-amino acid derivatives
-
A simple strategy for configurational assignments of alpha-amino acids has been developed by comparison of the proton NMR chemical shift values of the alpha hydrogens of N-phthaloyl protected alpha-amino acids in the presence of (R)-CSA 1 and (S)-CSA 1, respectively. Highly resolved NMR spectra can be obtained directly on the mixed solution of the chiral solvating agents with N-phthaloyl protected alpha-amino acids in NMR tubes, giving well distinguishable proton signals without interference which dramatically improve the accuracy of assignment and hasten the assigning procedure. The strategy is widely applicable for varied natural and non-natural amino acids.
- Chen, Zhongxiang,Fan, Hongjun,Yang, Shiwei,Bian, Guangling,Song, Ling
-
p. 6933 - 6939
(2018/10/02)
-
- 1-Imidoalkylphosphonium salts with modulated Cα–P+ bond strength: synthesis and application as new active α-imidoalkylating agents
-
An effective synthesis of the hitherto unknown 1-imidoalkylphosphonium salts has been developed in the reported study. The crucial step in the method included the decarboxylative α-methoxylation of N-phthaloyl- or N-succinylamino acids to the corresponding N-(1-methoxyalkyl)imides, followed by the displacement of the methoxy group by the triarylphosphonium group through melting of the imide derivative with triarylphosphonium tetrafluoroborate. The imidoalkylating properties of the obtained 1-imidoalkylphosphonium salts were tested using the Tscherniac–Einhorn-type reaction with aromatic hydrocarbons as a model reaction. It was found that the Cα–P+ bond strength can be considerably reduced and the imidoalkylation of arenes can be markedly facilitated using 1-imidoalkylphosphonium salts derived from triarylphosphines with electron-withdrawing substituents such as tris(m-chorophenyl)phosphine, tris(p-chlorophenyl)phosphine and tris[p-(trifluoromethyl)phenyl]phosphine. Microwave irradiation also considerably facilitates the cleavage of the highly polar Cα–P+ bond.
- Adamek, Jakub,Mazurkiewicz, Roman,W?grzyk, Anna,Erfurt, Karol
-
supporting information
p. 1446 - 1455
(2017/08/02)
-
- RUTHENIUM COMPLEXES AND THEIR USES AS CATALYSTS IN PROCESSES FOR FORMATION AND/OR HYDROGENATION OF ESTERS, AMIDES AND RELATED REACTIONS
-
The present invention relates to novel Ruthenium complexes of formulae A1-A4 and their use, inter alia, for (1) dehydrogenative coupling of alcohols to esters; (2) hydrogenation of esters to alcohols (including hydrogenation of cyclic esters (lactones) or cyclic di-esters (di-lactones), or polyesters); (3) preparing amides from alcohols and amines—(including the preparation of polyamides (e.g., polypeptides) by reacting dialcohols and diamines and/or polymerization of amino alcohols and/or forming cyclic dipeptides from p-aminoalcohols; (4) hydrogenation of amides (including cyclic dipeptides, polypeptides and polyamides) to alcohols and amines; (5) hydrogenation of organic carbonates (including polycarbonates) to alcohols or hydrogenation of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (6) dehydrogenation of secondary alcohols to ketones; (7) amidation of esters (i.e., synthesis of amides from esters and amines); (8) acylation of alcohols using esters; (9) coupling of alcohols with water and a base to form carboxylic acids; and (10) preparation of amino acids or their salts by coupling of amino alcohols with water and a base. The present, invention further relates to the use of certain known Ruthenium complexes for the preparation of amino acids or their salts from amino alcohols.
- -
-
Paragraph 0328
(2017/10/18)
-
- Reagent-free continuous thermal tert-butyl ester deprotection
-
Continuous processing enables the use of non-standard reaction conditions such as high temperatures and pressures while in the liquid phase. This expands the chemist's toolbox and can enable previously unthinkable chemistry to proceed with ease. For a series of amphoteric amino acid derivatives, we have demonstrated the ability to hydrolyze the tert-butyl ester functionality in protic solvent systems. Using a continuous plug flow reactor at 120–240 °C and 15–40 min reaction times, no pH modification or additional reagents are needed to achieve the desired transformation. The method was then expanded to encompass a variety of more challenging substrates to test selectivity and racemization potential. The acid products were generally isolated as crystalline solids by simple solvent exchange after the deprotection reaction in good to high yield and purity.
- Cole, Kevin P.,Ryan, Sarah J.,Groh, Jennifer McClary,Miller, Richard D.
-
supporting information
p. 6209 - 6217
(2017/09/30)
-
- Palladium-catalyzed sequential monoarylation/amidation of C(sp3)-H bonds: Stereoselective synthesis of α-amino-β-lactams and: Anti -α,β-diamino acid
-
Pd-Catalyzed sequential monoarylation/amidation of C(sp3)-H bonds of alanine enabled by a removable 5-methoxyquinolin-8-amine (MQ) auxiliary is described. This process is highly efficient and compatible with a variety of functional groups, providing a general and practical access to various α-amino-β-lactams. The synthetic potential of this protocol is further demonstrated by the stereoselective synthesis of orthogonally protected anti-α,β-diamino acids.
- Ling, Peng-Xiang,Fang, Sheng-Long,Yin, Xue-Song,Zhang, Qi,Chen, Kai,Shi, Bing-Feng
-
supporting information
p. 6351 - 6354
(2017/07/11)
-
- 1,2-Hydride Migration in Dialkyl α-Diazophosphonates Catalyzed by [Cu(MeCN)4]PF6: A Novel Approach to β-Amino (E)-Enylphosphonates
-
The regiospecific and stereoselective 1,2-migration reaction of dialkyl α-diazophosphonates for the synthesis of β-amino (E)-enylphosphonates is developed utilizing tetrakis(acetonitrile)copper(I) hexafluorophosphate [Cu(MeCN)4PF6] as the catalyst and N,N-dimethylformamide as an additive. A possible mechanism for the 1,2-migration reaction involving a metal carbene is presented. An investigation on the E/Z isomer selectivity of this process demonstrates that steric factors play an important role on the outcome. This process provides a straightforward access to β-amino (E)-enylphosphonates in moderate to good yields.
- Ge, Haihong,Liu, Shuang,Cai, Yan,Sun, Yuchao,Miao, Zhiwei
-
supporting information
p. 448 - 454
(2016/01/28)
-
- Design, synthesis and anti-cancer activity evaluation of podophyllotoxin-norcantharidin hybrid drugs
-
In this study, we designed and synthesized eighteen podophyllotoxin-norcantharidin hybrid drugs which could exhibit more potent anti-cancer activity than the parent drugs. Through the anti-proliferation assay, the most potent anti-cancer agent was screened out, namely Q9 (IC50?=?0.88?±?0.18?μM against MCF-7 cell line), and it showed lower cytotoxicity against non-cancer cells, human embryonic kidney cells (293T) (IC50?=?54.38?±?3.78?μM). Additionally, based on the flow cytometry analysis result, it can cause a remarkable cell cycle arrest at G2/M phase and induce apoptosis in MCF-7 cells more significantly than podophyllotoxin or norcantharidin per se. Moreover, the expression of cell cycle relative protein CDK1 was up regulated while a protein required for mitotic initiation, Cyclin B1 was down regulated. Furthermore, according to the confocal microscopy observation results, it was shown that Q9 was a potent tubulin polymerization inhibitor and the effect is comparable to that of colchicine. For further investigation on the aforementioned mechanisms, we performed western blot experiments, thus finding the increase of the cleavage of PARP. Consistent with these new findings, molecular docking observations suggested that compound Q9 could be developed as a potential anticancer agent.
- Han, Hong-Wei,Qiu, Han-Yue,Hu, Cui,Sun, Wen-Xue,Yang, Rong-Wu,Qi, Jin-Liang,Wang, Xiao-Ming,Lu, Gui-Hua,Yang, Yong-Hua
-
supporting information
p. 3237 - 3242
(2016/07/12)
-
- Direct, visible light-sensitized benzylic C[sbnd]H fluorination of peptides using dibenzosuberenone: selectivity for phenylalanine-like residues
-
A visible light-sensitized benzylic sp3C[sbnd]H fluorination protocol using dibenzosuberenone (5?mol?%) and Selectfluoris optimized for the direct functionalization of phenylalanine-like residues in short chain peptides. Amino acids, dipeptides, and tripeptides undergo benzylic fluorination with remarkable regioselectivity in the presence of protected basic, acidic, and nonpolar side chains (including those with tertiary sites). Additionally, protecting group compatibility, a gram scale application, and competition experiments were explored.
- Bume, Desta Doro,Pitts, Cody Ross,Jokhai, Rayyan Trebonias,Lectka, Thomas
-
supporting information
p. 6031 - 6036
(2016/09/16)
-
- KetoABNO/NOx Cocatalytic Aerobic Oxidation of Aldehydes to Carboxylic Acids and Access to α-Chiral Carboxylic Acids via Sequential Asymmetric Hydroformylation/Oxidation
-
A method for aerobic oxidation of aldehydes to carboxylic acids has been developed using organic nitroxyl and NOx cocatalysts. KetoABNO (9-azabicyclo[3.3.1]nonan-3-one N-oxyl) and NaNO2 were identified as the optimal nitroxyl and NOx sources, respectively. The mildness of the reaction conditions enables sequential asymmetric hydroformylation of alkenes/aerobic aldehyde oxidation to access α-chiral carboxylic acids without racemization. The scope, utility, and limitations of the oxidation method are further evaluated with a series of achiral aldehydes bearing diverse functional groups.
- Miles, Kelsey C.,Abrams, M. Leigh,Landis, Clark R.,Stahl, Shannon S.
-
supporting information
p. 3590 - 3593
(2016/08/16)
-
- 3D-QSAR-aided design, synthesis, in vitro and in vivo evaluation of dipeptidyl boronic acid proteasome inhibitors and mechanism studies
-
Proteasome had been clinically validated as an effective target for the treatment of cancers. Up to now, many structurally diverse proteasome inhibitors were discovered. And two of them were launched to treat multiple myeloma (MM) and mantle cell lymphoma (MCL). Based on our previous biological results of dipeptidyl boronic acid proteasome inhibitors, robust 3D-QSAR models were developed and structure-activity relationship (SAR) was summarized. Several structurally novel compounds were designed based on the theoretical models and finally synthesized. Biological results showed that compound 12e was as active as the standard bortezomib in enzymatic and cellular activities. In vivo pharmacokinetic profiles suggested compound 12e showed a long half-life, which indicated that it could be administered intravenously. Cell cycle analysis indicated that compound 12e inhibited cell cycle progression at the G2M stage.
- Lei, Meng,Feng, Huayun,Wang, Cheng,Li, Hailing,Shi, Jingmiao,Wang, Jia,Liu, Zhaogang,Chen, Shanshan,Hu, Shihe,Zhu, Yongqiang
-
p. 2576 - 2588
(2016/05/10)
-
- Dipeptide boric acid composed of carboxylic acid and alpha-amino acid as well as ester compound thereof, and preparation method and application of dipeptide boric acid and ester compound thereof
-
The invention belongs to the field of drug synthesis and in particular relates to a series of novel peptide boric acids as well as an ester compound or pharmaceutical salt thereof, and a preparation method and application of the peptide boric acids as well as the ester compound or pharmaceutical salt thereof in pharmacodynamics. A structure of the peptide boric acid and the ester compound or pharmaceutical salt thereof is shown in a formula I (described in the specification). The compound provided by the invention can be used for preparing a proteasome inhibitor and can further be used for treating solid tumours and blood tumours, wherein the solid tumours are selected from non-small cell lung cancer, small cell lung cancer, lung adenocarcinoma, lung squamous carcinoma, pancreatic cancer, breast cancer, prostate cancer, liver cancer, skin cancer, epithelial cell cancer, gastrointestinal stromal tumor, nasopharynx cancer and leukemia; and the blood tumours are selected from multiple myeloma, mantle cell lymphoma and histiocytic lymphoma.
- -
-
Paragraph 0090; 0091; 0094; 0095
(2016/12/01)
-
- Chiral Pool-Based Synthesis of Naphtho-Fused Isocoumarins
-
A variety of chiral derivatives of benzo[d]naphtho[1,2-b]pyran-6-one were prepared in a single step by Et3N-mediated condensation of homophthalic anhydride with different derivatives of (S)-amino acid chlorides at -5 °C by employing a chiral pool methodology. Chirality 27:951-957, 2015.
- Raza, Abdul Rauf,Saddiqa, Aisha,?akmak, Osman
-
p. 951 - 957
(2015/11/16)
-
- Development of modifiable bidentate amino oxazoline directing group for Pd-catalyzed arylation of secondary C-H bonds
-
Abstract A novel bidentate α-amino oxazolinyl directing group has been developed. Different from previous directing groups, this newly designed directing group was easily prepared from amino acids and modified in structure. This auxiliary preferentially effects functionalization at secondary C(sp3)-H bonds, rather than at aryl C(sp2)-H bonds. The diastereoselectivity of direct arylation between geminal secondary C(sp3)-H bonds in linear molecules has also been realized for the first time with a chiral directing group by remote chirality relay. Two diastereoisomers are produced with the same chiral source by changing the substituents of substrates and aryl halides. A new direction: A multifunctional amino oxazoline directing group that is readily available from amino acids, has been developed, which can induce chemo-, regio- and diastereoselectivity in secondary C(sp3)-H arylation reactions. Furthermore, this directing group is removable and modifiable. Steric control and counterions play important roles in the relayed chirality transfer.
- Chen, Kang,Li, Zhao-Wei,Shen, Peng-Xiang,Zhao, Hong-Wei,Shi, Zhang-Jie
-
supporting information
p. 7389 - 7393
(2015/05/13)
-
- Design, synthesis and mechanism of novel shikonin derivatives as potent anticancer agents
-
In this study, a series of novel shikonin derivatives (30-49) were designed and synthesized and their anti-proliferative activities were evaluated against five different cancer cell lines, including HeLa, HepG2, MCF-7, BGC and A549. Some of the compounds show strong anti-proliferative effects against HeLa, HepG2 and MCF-7 with IC50 values ranging from 1.26 to 18.50 μM and show lower side effects towards normal cell lines as compared to shikonin. Compared to other compounds and shikonin itself, compound 40 displayed much stronger anti-proliferative effects against various cancer cell lines. Furthermore, the flow cytometry results demonstrated that compound 40 could obviously induce apoptosis in a dose- and time-dependent manner and also cause cell cycle arrest at the G2/M phase. For further investigation of the aforementioned mechanisms, we performed Western blot experiments and found that the cleavage of PARP and upstream caspase-3 increased; moreover, caspase-9 was activated by cleavage but not caspase-8. These aforementioned results also indicate that compound 40 could induce caspase-9 involved apoptosis and G2/M phase cell cycle arrest via the P21, p-CDC2 (Tyr15) pathway independent of P53.
- Baloch, Shahla Karim,Ma, Lin,Wang, Xue-Liang,Shi, Jing,Zhu, Yu,Wu, Feng-Yao,Pang, Yan-Jun,Lu, Gui-Hua,Qi, Jin-Liang,Wang, Xiao-Ming,Gu, Hong-Wei,Yang, Yong-Hua
-
p. 31759 - 31767
(2015/04/22)
-
- Pd(II)-catalyzed C(sp3)-H arylation of amino acid derivatives with click-triazoles as removable directing groups
-
By using click-triazoles as conveniently approachable and removable directing groups, the direct palladium-catalyzed C(sp3)-H arylation of amino acid derivatives with various aryl iodides bearing different electronic properties has been achieved. Notably, the desired amino acid molecule can be obtained by the cleavage of the tethered click-triazoles after the catalytic reaction, which aims to provide a practical protocol for the accessibility of both natural and synthetic amino acids.
- Zhang, Guofu,Xie, Xiaoqiang,Zhu, Jianfei,Li, Shasha,Ding, Chengrong,Ding, Ping
-
supporting information
p. 5444 - 5449
(2015/05/20)
-
- Trifluoroborane-catalyzed C-H functionalization/S-H insertion reaction: Construction of N,S-acetal quaternary centers
-
Abstract The trifluoroborane-catalyzed C-H functionalization/S-H insertion reaction of α-diazophosphonates with thiols has been developed. A plausible reaction mechanism has been proposed to understand the combined reaction. This process provides straightforward access to N,S-acetals containing quaternary centers in moderate to good yields and chemoselectivity.
- Cai, Yan,Ge, Haihong,Sun, Weize,Miao, Zhiwei
-
supporting information
p. 1669 - 1677
(2015/06/02)
-
- A multigram-scale lower E-factor procedure for MIBA-catalyzed direct amidation and its application to the coupling of alpha and beta aminoacids
-
The development of direct and atom-economical amidation methods is of high priority because of the importance of amides and peptides as components of pharmaceuticals and commodity chemicals. This article describes the identification of more economical and more practical conditions for direct amidation of carboxylic acids and amines using the MIBA catalyst (5-methoxy-2-iodophenylboronic acid, 6) and its application to the coupling of α- and β-amino acid derivatives. It is now possible to use half of the quantity of molecular sieves prescribed in the original procedure, at a higher concentration leading to a reduction of waste and a substantially improved E-factor. This procedure was validated in the multigram scale preparation of prototypical amides, including aminoacids, using toluene as the solvent. Because of substrate inhibition of the catalyst with monoprotected α-aminoacids, the use of doubly-protected N-phthaloyl α-aminoacids or α-azidoacids is required in order to produce dipeptide products in moderate yields. β-Aminoacids do not suffer from this problem, and Boc-β-aminoacids can be coupled successfully. Unlike other boronic acid catalysts, 6 is active under ambient and low-heat conditions, which helps prevent any epimerization of chiral α-aminoacid derivatives.
- Fatemi, Solmaz,Gernigon, Nicolas,Hall, Dennis G.
-
p. 4016 - 4028
(2015/07/15)
-
- Silicon-containing poly(esters) with halogenated bulky side groups. Synthesis, characterization and thermal studies
-
Poly(esters) (PEs) derived from diacids containing bulky side groups, which have an halogenated (Cl, Br) imide ring, an aminoacidic residue (glycine, l-alanine, l-valine) and an amide group were obtained with a silicon-containing diphenol. Also PEs without the aminoacidic residue were obtained. PEs were characterized by IR and NMR spectroscopy, and the results were in agreement with the proposed structures. PEs were obtained with good yields and moderate or high ηinh values. PEs were soluble in aprotic polar solvents and were swollen in other solvents like m-cresol and THF. The Tg values were determined and it was possible to see a tendency in the sense that when the size of the atom (Cl, Br) bonded to the imidic ring is increased, the Tg values decreased, also for those PEs obtained without the aminoacidic residue. The thermal decomposition temperatures showed that only two PEs can be considered as thermostable, considering TDT values above 400°C at 10% of weight lost. The other PEs showed good thermal stability, showing in general a decrease of the TDT values when the volume of the side group, is increased. PEs showed UV-vis transparency at 400 nm lower than 20%, but between 500 and 600 nm, showed 80% transparency. PEs containing halogen atoms showed flame retardancy in a simple essay, with respect to PEs without halogen atoms in which the combustion was complete.
- Tagle,Terraza,Tundidor-Camba,Coll
-
p. 49132 - 49142
(2015/06/16)
-
- LIGAND-CONTROLLED C(SP3)-H ARYLATION AND OLEFINATION IN SYNTHESIS OF UNNATURAL CHIRAL ALPHA AMINO ACIDS
-
The use of ligands to tune the reactivity and selectivity of transition metal-catalysts for C(-sp3)-H bond functionalization is a central challenge in synthetic organic chemistry. Herein, we report a rare example of catalyst-controlled C(sp3)-H arylation using pyridine and quinoline derivatives: the former promotes exclusive monoarylation, whereas the latter activates the catalyst further to achieve diarylation. Successive application of these ligands enables the sequential diarylation of a methyl group in an alanine derivative with two different aryl iodides, affording a wide range of β-Ar-p-Ar ' -cc-amino acids with excellent levels of diastereoselectivity (d.r. > 20:1). Both configurations of the β-chiral center can be accessed by choosing the order in which the aryl groups are installed. The use of a quinoline derivative as a ligand also enables C(sp3)-H olefination of a protected alanine.
- -
-
Page/Page column 80-85
(2015/10/05)
-
- Ligand-Enabled Cross-Coupling of C(sp3)-H Bonds with Arylsilanes
-
Pd(II)-catalyzed cross-coupling of C(sp3)-H bonds with organosilicon coupling partners has been achieved for the first time. The use of a newly developed quinoline-based ligand is essential for the cross-coupling reactions to proceed.
- He, Jian,Takise, Ryosuke,Fu, Haiyan,Yu, Jin-Quan
-
supporting information
p. 4618 - 4621
(2015/04/27)
-
- Phthaloyl amino acids as anti-inflammatory and immunomodulatory prototypes
-
A series of phthalimide analogs were synthesized by derivatization of phthalic anhydride, a highly toxic substance, using a "one pot" condensation reaction to α-amino acids. All phthaloyl amino acid derivatives presented anti-oral inflammatory activity, but compounds 2e and 2g were found to possess the best activities comparable to thalidomide.Most of the compounds effectively suppressed nitric oxide production inmurine cells stimulatedwith lipopolysaccharide. N-phthaloyl amino acids did not exhibit any significant cytotoxicity in vitro when tested against tumor cells as well as a spleen cell culture of BALB/c mice. Compounds 2a, 2g, and 2h were able to inhibit TNF-α and IL-1β production by macrophages. At the same concentration, thalidomide did not exhibit significant inhibitory activity. Springer Science+Business Media 2013.
- Leite, Ana Cristina Lima,Barbosa, Fabio Fernandes,Cardoso, Marcos Verissimo De Oliveira,Moreira, Diogo R. M.,Coelho, Lucas Cunha D.,Da Silva, Elany Barbosa,Filho, Gevanio Bezerra De Oliveira,De Souza, Valdenia Maria Oliveira,Pereira, Valeria Rego A.,Reis, Luiza De C.,Ferreira, Paulo Michel Pinheiro,Pessoa, Claudia,Wanderley, Almir Goncalves,Mota, Fernanda Virginia B.,Da Silva, Teresinha G.
-
p. 1701 - 1708
(2014/05/06)
-
- Chiron based synthesis of isocoumarins: Reactivity of α-substituted carboxylic acids
-
The asymmetric synthesis of a novel (S)-isocoumarin has been attempted in a single step by the coupling of homophthalic acid with (S)-N-protected amino acids and α-chloroacids at high temperature by exploiting a chiral pool methodology. The coupling of homophthalic acid with N-protected (S)-amino acids gave exclusion of the carboxyl/alkyl group. However, coupling of homophthalic acid with α-chloroacids afforded asymmetric isocoumarins in high yield.
- Saddiqa, Aisha,Raza, Abdul R.,Black, David Stc.,Kumar, Naresh
-
p. 736 - 743
(2014/06/09)
-
- Unexpected stereoselective synthesis of (Z)-β-alkenyl substituted β-amino phosphonates through β,γ-dihydrogen shift reaction catalyzed by a copper(I) complex and iodine [Cu(MeCN)4]PF 6/I2
-
A series of dialkyl a-diazophosphonates has been prepared from natural amino acids. The diazo decomposition of these diazophosphonate compounds with tetrakis(acetonitrile)copper(I) hexafluorophosphate/iodine, [Cu(MeCN) 4]PF6/I2, as catalyst has been investigated. It was found that the diazo decomposition of dialkyl a-diazophosphonates gave a mixture of β,γ-dihydrogen shift and 1,2-hydride migration products and afforded β-alk- enyl-substituted β-amino phosphonates with the Z configuration. The mechanism of this novel diazo decomposition process was discussed.
- Cai, Yan,Lyu, Hairong,Yu, Chengbin,Miao, Zhiwei
-
supporting information
p. 596 - 602
(2014/05/20)
-
- Novel phthalimide derivatives with TNF-α and IL-1β expression inhibitory and apoptotic inducing properties
-
Modulation of the immune system is an emerging concept in the control of tumor growth. Bearing in mind the pharmacological properties of thalidomide and its phthalimide derivatives, we describe here the structural design, synthesis and pharmacological evaluation of N-acylhydrazones derived from phthalimide. The ability of these N-acylhydrazones in inhibiting the secretion of TNF-α in stimulated cells as well as in inhibiting the transcription of the TNF-α gene was evaluated. We identified N-acylhydrazones 6b and 9c, which substantially impaired TNF-α secretion, expression and reduced IL-1β production similar to thalidomide or Revlimid. N-Acylhydrazone 9c was also able to induce apoptosis in Jurkat cells, however it does not have either antiproliferative properties or cytotoxicity for mouse splenocytes. Beyond that, we have assayed the ability of these compounds to induce cell death and a number of them are able to induce apoptosis.
- Coêlho, Lucas Cunha Duarte,De Oliveira Cardoso, Marcos Veríssimo,Moreira, Diogo Rodrigo Magalh?es,De Moraes Gomes, Paulo André Teixeira,Cavalcanti, Suellen Melo Tibúrcio,Oliveira, Arsenio Rodrigues,De Oliveira Filho, Gevanio Bezerra,Pessoa De Siqueira, Lucianna Rabelo,De Oliveira Barbosa, Miria,De Oliveira Borba, Elizabeth Fernanda,Da Silva, Teresinha Gon?alves,Kaskow, Belinda,Karimi, Mahdad,Abraham, Lawrence J.,Leite, Ana Cristina Lima
-
p. 758 - 765
(2014/06/10)
-
- Combined C-H functionalization/O-H insertion reaction to form tertiary β-alkoxy substituted β-aminophosphonates catalyzed by [Cu(MeCN) 4]PF6
-
The copper-catalyzed C-H functionalization/O-H insertion reaction of α-diazophosphonates with alcohols has been developed with iodine as an additive. In order to understand this reaction, we present here a possible mechanism for the combined reaction. This process provides straightforward access to tertiary β-alkoxy substituted β-aminophosphonate derivatives with moderate to good yields. The Royal Society of Chemistry.
- Cai, Yan,Lu, Yuchen,Yu, Chengbin,Lyu, Hairong,Miao, Zhiwei
-
supporting information
p. 5491 - 5499
(2013/09/02)
-
- Use of a readily removable auxiliary group for the synthesis of pyrrolidones by the palladium-catalyzed intramolecular amination of unactivated γ C(sp3)-H Bonds
-
Easy on, easy off: Directing groups found to promote the palladium-catalyzed amination of γ C(sp3)-H and C(sp 2)-H bonds of secondary amides included 5-methoxy-8-aminoquinoline, which can be removed under mild conditions (see scheme; CAN=ceric ammonium nitrate). In conjunction with a β-C-H methylation or γ-C-H arylation step, the γ-C(sp3)-H amination provided access to complex pyrrolidones from readily available precursors. Copyright
- He, Gang,Zhang, Shu-Yu,Nack, William A.,Li, Qiong,Chen, Gong
-
supporting information
p. 11124 - 11128
(2013/10/22)
-
- Stereoselective synthesis of chiral α-amino-β-lactams through palladium(II)-catalyzed sequential monoarylation/amidation of C(sp 3)-H Bonds
-
Give Me an Ar, give Me an N! Arylation of the methyl group in a simple derivative of readily available alanine under palladium catalysis was followed by intramolecular amidation at the same position to give chiral α-amino-β-lactams with a wide range of aryl substituents (see scheme; Phth=phthaloyl). The α-amino-β-lactams were obtained in moderate to high yields with good functional-group tolerance and high diastereoselectivity. Copyright
- Zhang, Qi,Chen, Kai,Rao, Weihao,Zhang, Yuejun,Chen, Fa-Jie,Shi, Bing-Feng
-
supporting information
p. 13588 - 13592
(2014/01/06)
-
- Nonnatural amino acid synthesis by using carbon-hydrogen bond functionalization methodology
-
Taking direction well: Substituted phenylalanine derivatives were prepared by C-H bond functionalization (see scheme). The syntheses are highly convergent and employ an N-phthaloylalanine with a 2-thiomethylaniline directing group. The use of an 8-aminoquinoline directing group allows for the diarylation of methyl and the diastereoselective arylation of methylene groups. Copyright
- Tran, Ly Dieu,Daugulis, Olafs
-
supporting information; experimental part
p. 5188 - 5191
(2012/07/27)
-
- Rhodium(II)-catalyzed intramolecular carbonyl ylide formation of α-diazo-β-ketoesters derived from N-phthaloyl-α-amino acids
-
Starting from L-alanine, L-phenylalanine, L-leucine, L -norleucine, or L-isoleucine, 2-diazo-3-oxo-4-phthalimido-alkanoates 8 were prepared in three steps. Considerable racemization occurred at the stage of the 3-oxo-4-phthalimido-alkanoates 7. Dirhodium tetraacetate effectively catalyzed the intramolecular formation of carbonyl ylides 9, which in the absence of a trapping reagent underwent a [3+3] cycloaddition reaction to form the dimers 10. Carbonyl ylides 9 underwent [3+2] cycloaddition reactions with several electron-deficient alkenes and alkynes to give oxygen and nitrogen containing multicyclic systems 12-16. The keto group of the αoxy-β-ketoester moiety of cycloadducts 2 and 12 is easily hydrated to give the gem-diol. ARKAT-USA, Inc.
- Enssle, Marc,Buck, Stefan,Werz, Roland,Maas, Gerhard
-
p. 149 - 171
(2013/09/24)
-
- Synthesis of new cyclic imides derivatives with potential hypolipidemic activity
-
Certain new nitrogen-substituted derivatives of cyclic imides phthalimide (a), 1,8-naphthalimide (b), and diphenimide (c), were synthesized aiming to obtain potent hypolipidemic agents. Thus, 2-(N-imido) propanoic acids, 2-(N-phthalimido)-2-methylpropionic acid, and their ethyl esters were synthesized (Target derivative A). Also their corresponding N-substituted-2-(N- imido) propionamides and 2-(N-phthalimido)-2-methylpropionamides were prepared (Target derivative B). In addition, N-phthalimidomethyleneoxy acetate was prepared. Some of the newly prepared compounds were subjected to 3D studies and were found to be superimposed on Clofibrate, which is the first generation of fibrate drugs. The preliminary evaluation of hypolipidemic activity of the newly prepared compounds against triton WR-1339-induced hyperlipidemia in rat showed that several derivatives have demonstrated significant lowering of serum total cholesterol and triglyceride levels at dose of 150 mg/kg/i.p. comparing with Fenofibrate which is one of the second generations of fibrate drugs. Springer Science+Business Media, LLC 2010.
- El-Zahabi, Mohamed A.,Gad, Laila M.,Bamanie, Faida H.,Al-Marzooki, Zohair
-
experimental part
p. 75 - 84
(2012/06/01)
-
- Organocatalytic, oxidative, intermolecular amination and hydrazination of simple arenes at ambient temperature
-
New atom-economical, environmental friendly, direct oxidative intermolecular processes of amination and hydrazination of nonprefunctionalized arenes were developed. The products were formed in a good regioselective manner under organocatalytic conditions
- Samanta, Rajarshi,Antonchick, Andrey P.,Bauer, Jonathan O.,Strohmann, Carsten
-
p. 5518 - 5521,4
(2012/12/12)
-
- Hydrogen bonding chains and rings structural motifs in new series of N-phthaloyl aminocarboxylic acid derivatives. Solid state microwave synthesis, structural chemistry, computational calculations and antimicrobial activity
-
A series of six N-phthaloyl aminocarboxylic acids were synthesized by using improved microwave irradiation with a multimode reactor. X-ray single crystal diffraction established the molecular structure of three N-protected aminocarboxylic acids derivatives, and spectral data agree with these in solution. The hydrogen bonding characteristics of this class of molecules are discussed on the basis of crystal structural analyses, MP2/DFT quantum calculations and Hirshfeld surfaces analyses. The relative strengths of the structural O-H?O and C-H?O hydrogen bonding chain and ring motifs are compared. Antimicrobial activities of 2-(1,3-dioxoisoindolin-2-yl)propanoic acid, 2-(1,3-dioxoisoindolin-2-yl)-3-phenylpropanoic acid and 2-(4-(1,3-dioxoisoindolin-2-yl)phenyl)acetic acid, were screened against three pathogenic strains; only the first two compounds were found to be quite sensitive against Gram +ve and Gram -ve bacterial strains, respectively. A relative structure-function relationship is observed.
- Al-Farhan, Khalid,Ghazzali, Mohamed,Al-Hazimi, Hassan M.A.,El-Faham, Ayman,Reedijk, Jan
-
scheme or table
p. 269 - 275
(2011/08/03)
-
- Substituted Phenylpiperazinyl Aralkylalcohol Derivatives, Pharmaceutical Compositions Containing Such Derivatives and Uses Thereof
-
The invention relates to a substituted phenylpiperazine aryl alkanol derivative represented by the following general formula and its salt and hydrate, wherein C1 and C2 represent chiral carbon atoms, and the compound is one of the six isomers: (1RS, 2SR), (1RS, 2RS), (1R, 2S), (1S, 2S), (1R, 2R) or (1S, 2R); and R, R1, R2, R3 and Ar are as defined in the specification. The derivative is non-opioid analgesic, has good analgesic effect and relatively small side effects. The invention also relates to a composition comprising the derivative and its use.
- -
-
Page/Page column 17
(2011/12/13)
-
- Synthesis and nootropic activity of some 2,3-Dihydro-1H-isoindol-1-one derivatives structurally related with piracetam
-
Three 2,3-dihydro-1H-isoindol-1-ones structurally related with piracetam (=2-oxopyrrolidine-1-acetamide) have been synthesized and tested for their nootropic effects in the passive avoidance test in mice. Compounds (RS)-2, (R,R)-3, and (R,S)-3 were obtained in good yields in only two steps starting from methyl dl-phthaloylalanine. Compound (RS)-2 exhibited nootropic activity at lower doses than piracetam, used as reference drug, but it showed lower efficacy. Whereas diastereoisomers (R,R)-3 and (R,S)-3 were as potent as piracetam to revert amnesia induced by scopolamine, (R,S)-3 showed lower efficacy than (R,R)-3. Only (R,R)-3 showed myorelaxant effect at doses of 10 and 30mg/kg; other compounds did not exhibit any anticonvulsant, sedative, myorelaxant, or impaired motor-coordination effect in mice. These synthesized 2,3-dihydro-1H-isoindol-1-one derivatives constitute a new kind of nootropic compounds.
- Reyes, Adelfo,Huerta, Leticia,Alfaro, Marisol,Navarrete, Andres
-
experimental part
p. 2718 - 2726
(2011/08/10)
-
- Diastereoselective synthesis of γ-phthalimido-β-hydroxy esters and n-protected 4-amino-1,3-diols starting from natural α-amino acids
-
An efficient diastereoselective synthes.is of γ-phthalimido-β- hydroxy esters and N-protected 4-amino-1,3- diols, starting from natural amino acids is described. The key synthetic strategies involve diastereoselective reduction of γ-phthalimido-β-keto esters with NaBH4 as hydride reducing. The diastereoselective reduction has been found to be highly selective if carried out in methanol at -78°C. Furthermore, the resulting diastereomeric mixture of the reduced products was successfully and cleanly separated by column chromatography.
- Essersi, Amel,Touati, Ridha,Hassine, Bechir Ben
-
scheme or table
p. 69 - 72
(2010/08/05)
-
- Catalytic asymmetric protonation of α-amino acid-derived ketene disilyl acetals using P -Spiro diaminodioxaphosphonium barfates as chiral proton
-
Chiral diaminodioxaphosphonium salts have been developed and their unique abilities as a chiral proton have been revealed through the establishment of a highly enantioselective protonation of α-amino acid-derived ketene disilyl acetals.
- Uraguchi, Daisuke,Kinoshita, Natsuko,Ooi, Takashi
-
supporting information; scheme or table
p. 12240 - 12242
(2010/11/19)
-
- Chemical resolution of (±)-calanolide A, (±)-cordatolide A and their 11-demethyl analogues
-
The chemical resolution of (±)-calanolide A and (±)-cordatolide A into their corresponding optically active enantiomers is described. Their inhibitory activities against HIV-1 are tested in vitro.
- Ma, Tao,Gao, Qi,Chen, Zhiwei,Wang, Lin,Liu, Gang
-
p. 1079 - 1083
(2008/12/20)
-
- Cyclomaltooligosaccharide-assisted spectroscopic discrimination of phthalimido-derived amino acids through the formation of molecular aggregates
-
Spectroscopic evidence was used to demonstrate the formation of molecular associates in an aqueous solution of phthalimido tryptophan. These molecular associates are loosely formed through π-π aromatic stacking, properties that are not sufficient to cause NMR spectroscopic enantiomeric discrimination. A cyclomaltooligosaccharide with a larger cavity, such as cyclomaltooctaose (γ-cyclodextrin), is capable of forming a ternary complex with these molecular associates and enhances π-π aromatic stacking interactions, resulting in NMR enantiomeric discrimination. Electrospray-ionization mass spectroscopy (ESIMS) and NOESY two-dimensional NMR spectroscopic methods were used to study these complexes. Association constants and thermodynamic data for these cyclomaltooligosaccharide complexes were also estimated.
- Jursic, Branko S.,Patel, Paresh K.
-
p. 2858 - 2866
(2007/10/03)
-