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1.
The methyl esters of colchicidylglycyl-L-leucine, -L-phenylalanine, and-L-tryptophan and the ethyl esters of colchicidylglycylglycine, -L-isoleucine,-L-valine, -L-tyrosine, and -L-glutamic acid have been obtained by the condensation of colchicidylglycine and esters of amino acids. The structures of the compounds have been confirmed on the basis of their UV spectra and nuclear magnetic resonance spectra.Institute of Molecular Biology and Biochemistry, Kazakh SSR Academy of Sciences, Alma-Ata. Institute of Molecular Biology, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 91–95, January–February, 1989.  相似文献   

2.
The 13C-NMR. spectra of a number of colchicine derivatives are given comprising examples of the normal series ( 4→10 ), iso series ( 11→16 ) and colchicine series ( 17 ), which were either reported in the literature or obtained by partial synthesis or degradation reactions. The 13C-NMR. assignments were made by comparisons with known compounds and selective single-frequency offresonance decoupling experiments. Selective proton decoupling experiments have also allowed assignments of the H —C(11) and H —C(12) protons of the iso and colchicine series.  相似文献   

3.
[reaction: see text] A series of novel chiral ionic liquids (CILs) has been synthesized and fully characterized. The reaction of 1-methyl-2-imidazolecarboxaldehyde and chiral amino alcohols followed by reduction is key to the design of these new CILs. This is the first time that CILs have been synthesized by introducing chiral scaffolds on the C-2 position of the imidazolium cation of ILs. The simple and straightforward procedure resulted in CILs as colorless oils at room temperature in good yields.  相似文献   

4.
Based upon the structural similarities of cannabinoid derivatives which inhibit the biosynthesis of prostaglandins with those of the potent inhibitor, indomethacin, several cannabinoid derivatives possessing C-3 side chain carboxylic acid functionalities were prepared.  相似文献   

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8.
In this letter, we describe the ring-rearrangement metathesis (RRM) of bicyclic amino acid derivatives. The procedure is of use for the synthesis of constrained amino acid and peptide derivatives with potential as reverse-turn inducers.  相似文献   

9.
A series of novel d-glucose derivatives, functionalized at the C-2 or the C-6 position with an iminodiacetic acid moiety for transition-metal complexation, has been prepared. The sugar and the metal-chelating parts are separated by either propyl or octyl chains and were introduced by the reaction of bromoalkylamine. Either N-1-Boc-3-bromopropylamine (17) or N-(8-bromooctyl)phthalimide (19) reacted with methyl 3,5,6-tri-O-benzyl-alpha-beta-d-glucofuranoside (4) (C-2 position) and 1,2:3,5-(O-methylene)-alpha-d-glucose (11) (C-6 position), respectively, in the presence of sodium hydride in DMF at room temperature, affording the desired intermediates. For aminopropyl derivatives, yields varied between 57% and 65%, and for aminooctyl derivatives, yields varied between 40% and 71%. After deprotection of the amine functionality, the metal chelate was built up by dialkylation (6a-c and 13a,b) with methyl bromoacetate in the presence of triethylamine under reflux in THF. Yields varied between 56% and 69% for the glucose modified at the C-2 position and between 58% and 62% for the one modified at the C-6 position. All compounds were characterized by 1H or 13C NMR or both, IR, and mass spectroscopy. Final products were isolated as a mixture of alpha and beta anomers.  相似文献   

10.
A number of aminoacyl derivatives of 4-phenylcoumarin have been obtained by the condensation of N-hydroxysuccinimide esters of 7-(1-carboxyalkoxy)-4-phenylcoumarins with L-amino acids and their derivatives.Kiev Taras Shevchenko University, Chemical Faculty, 252033, Kiev, Ul. Vladimirskaya, 65, tel/fax 225 12 73. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 464–469, July–August, 1999.  相似文献   

11.
Phenylalanine ethyl ester-selective polymers have been prepared using the ion-pair association of substrate and carboxyl-containing vinyl monomers in the polymerization step.  相似文献   

12.
Thin layer chromatography of Dansyl amino acid derivatives   总被引:10,自引:0,他引:10  
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13.
The efficient and direct synthesis of protected biaryl amino acids, including dityrosine (50% overall yield over 3 steps), by Negishi cross-coupling of the serine-derived organozinc reagent 4 with iodo- and di-iodobiaryls, is reported. An improved, although still not perfect, diiodination of 2,2'-biphenol has been achieved using NMe3BnICl2-ZnCl2. Protection of phenolic hydroxyl groups as acetates, rather than benzyl ethers, is required for efficient cross-coupling, and evidence for acetyl migration has been observed during debenzylation of a substituted 2-acetoxy-2'-benzyloxybiaryl. Aromatic C-I to C-Cl conversion has been detected as a minor reaction pathway in the palladium-catalyzed coupling of aryl iodide 3b with organozinc reagent 4.  相似文献   

14.
Background: Amide bonds in peptides and proteins typically adopt planar cis or trans conformations. Conversions between cis and trans amide conformations are necessary for protein folding and for many other processes, but are difficult to achieve since they involve disruption of the planarity of the bond. As a first step to understanding cis-trans isomerization, we set out to synthesize and characterize peptides that mimic the tilted or twisted amide structures that are postulated to form the intermediate states in this process.Results: We have synthesized a model amino acid and four dipeptide derivatives containing a methyl-substituted aziridine residue. Single crystals of phenacyl (2R, 3R)-benzyloxycarbonyl-3-methyl-2-aziridinecarboxylate and phenacyl (2R, 3R)-acetyl-glycyl-3-methyl-2-aziridine-carboxylate were obtained. Using X-ray diffraction analysis, we determined that the amide nitrogens of the aziridine rings have tetrahedral sp3-like geometry with tilt angles in the range of 37–38°. The 13C-NMR spectra indicate that the amide carbonyl is dramatically shifted downfield as a consequence of the tilt.Conclusions: In peptides containing a substituted aziridine ring, the orbitals of the amide nitrogen are constrained into a tilted configuration. These peptides may mimic the transition state between cis and trans amide conformations. This technique thus provides a novel strategy for the study of isomerization and other biorecognition processes.  相似文献   

15.
Fluorine chemistry has represented a hot topic in drug research over the last decade. Because of their pharmaceutical potential, fluorine-containing amino acids and related derivatives have acquired high importance among medicinal chemists. Therefore their synthesis and the development of various synthetic methods for these types of molecular scaffolds have gained increasing interest in synthetic organic chemistry. The current review focuses on synthetic protocols towards fluorine-containing amino acid derivatives through late-stage fluorination with various nucleophilic reagents, describing the access of various open-chain and cyclic α-, β-, γ-amino acid derivatives.  相似文献   

16.
[reaction: see text] An efficient and practical N-methylation of amino acid derivatives with dimethyl sulfate in the presence of sodium hydride and a catalytic amount of water is described. Reaction of water with sodium hydride generated highly reactive dry sodium hydroxide, which led to much faster reaction rates than powdered sodium hydroxide itself.  相似文献   

17.
It is suggested that the open-flask system for the acid hydrolysis of proteins described earlier can also be used to advantage for the alkaline hydrolysis of amino acid phenylthiohydantoin derivatives obtained in protein sequential analysis according to Edman. Results obtained under nitrogen and argon atmospheres are reported for the hydrolysis of 0.5 mumole of each phenylthiohydantoin derivative, which is the amount of protein that is usually employed in an automatic sequenator.  相似文献   

18.
The partial molar volumes at infinite dilution for a number of hydrochlorides and sodium salts of N-methyl derivatives of , -aminocarboxylic acids in water at 25°C are measured and related to their van der Waals volumes. Results indicate that 4.96±0.48 water molecules hydrate a betaine hydrochloride. Volumes of proton ionization and interaction terms are evaluated. Group contributions to the partial molar volumes are also reported.  相似文献   

19.
The dependence of the circular dichroism spectra of the amino acid derivatives of fullerene C60 on the structure of the initial α-amino acid was studied.  相似文献   

20.
Sialic acids are 9-carbon acidic sugars involved in a number of important biological processes and human diseases. As part of our ongoing interest in the development of novel sialic acids as biological probes, we have developed an efficient and simple synthesis of C-9 oxidised sialic acid derivatives. The key oxidative step involves the use of TEMPO under carefully controlled aqueous pH conditions.  相似文献   

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