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1.
A series of erythromycin-A oxime ether as well as esters have been synthesized. Ether derivatives were synthesized through the epoxy ether intermediate of erythromycin-9-oxime, followed by opening of the epoxy linkage through various amines, whereas esters have been prepared through DCC mediated protocol. These derivatives have been evaluated for antibacterial activity and found to be as active as erythromycin-A. 相似文献
2.
8-Oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid esters and derivatives were prepared and evaluated for cytotoxicity against A549 and P388 cell lines. Based on a novel chromophore precursor 8-oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile 1, the very insoluble 1 was converted to more soluble esters 5 and a series of 3-amino derivatives from 5 were obtained by mild S(N)Ar(H) reaction between 5 and various amines. The biological evaluation indicated that methyl esters 5a are the most cytotoxic with IC(50) values of 0.45 and 0.80 microM (against A549 and P388, respectively) among the parent esters 5a-5f, but 3-amino derivatives 4b and 4c of 5f with bromine showed the highest activity (with IC(50) values of 0.019-0.60 microM) among the 3-amino derivatives. 相似文献
3.
Tsumoto H Takahashi K Suzuki T Nakagawa H Kohda K Miyata N 《Bioorganic & medicinal chemistry letters》2008,18(2):657-660
We report the syntheses of C(60)-based active esters and the coupling of their C(60) moiety to various amines or alcohols. Methano[60]fullerene carboxylic acid was activated by esterification with N-hydroxysuccinimide (NHS) or pentafluorophenol (PFP) and the active esters were isolated. Reactions of the active esters with amines or alcohols proceeded easily to give a variety of compounds having the C(60) moiety. 相似文献
4.
V F Pozdnev 《International journal of peptide and protein research》1992,40(5):407-414
Activation of carboxylic acids was achieved via dialkyl pyrocarbonates (ROCO)2O, R = C2H5, i-C3H7, sec-C4H9, tert.-C4H9) in aprotic solvents in the presence tertiary amines. A convenient procedure for the preparation of carboxylic acid anhydrides from carboxylic acids and di-tert.-butyl pyrocarbonate in the presence of pyridine is reported. Analogously, di-isopropyl- or diethyl pyrocarbonate may be used in the presence of N-methylmorpholine (triethylamine). With pyridine, di-isopropyl- or diethyl pyrocarbonate carboxylic acids form isopropyl- or ethyl esters, respectively. A wide variety of esters were prepared in good yields in a one-pot procedure from carboxylic acids, including N-protected amino acids, and alcohols or from phenols by means of di-tert.-butyl pyrocarbonate in the presence of pyridine (Boc2O-pyridine system). t-Butyl esters of carboxylic acids were obtained by the same procedure with 4-dimethylaminopyridine. In the absence of carboxylic acid, with 4-dimethylaminopyridine Boc2O and alcohols generate alkyl tert.-butyl carbonates. 相似文献
5.
Santiago Conde Paloma Lpez-Serrano Ana Martínez 《Journal of Molecular Catalysis .B, Enzymatic》1999,7(5-6):299-306
Pyroglutamic acid esters, both (S)- and (R)-enantiomers, have been studied as substrates of the Candida antarctica lipase B catalyzed amidation in anhydrous organic solvents. They behaved as very good substrates when primary amines or ammonia were used as nucleophiles, affording the corresponding secondary and primary amides, respectively, but did not react with secondary amines. The reaction was enantioselective for the (R)-enantiomer of chiral amines although little kinetic difference was observed between (S)- and (R)-pyroglutamates as acyl donors. As an example of an infrequent reaction, free (S)-pyroglutamic acid may also act as a substrate of the reaction, but is much less reactive than its esters. 相似文献
6.
Tiwari VK Tewari N Katiyar D Tripathi RP Arora K Gupta S Ahmad R Srivastava AK Khan MA Murthy PK Walter RD 《Bioorganic & medicinal chemistry》2003,11(8):1789-1800
A series of N(1),N(n)-xylofuranosylated diaminoalkanes (3-9 and 11-18) has been synthesized either by reductive amination of deoxy xylouloses (2a, 2b) with amines followed by one pot reduction with NaBH(4) or NaCNBH(3); or by 1,4-conjugate addition of amines to glycosyl olefinic esters (10a, 10b). The compounds were screened for their interference with filarial worms' glutathione metabolism, a potential target for chemotherapeutic attack. Interestingly, these compounds affected intracellular glutathione, gamma-glutamyl cysteine synthetase, glutathione reductase and glutathione-S-transferase(s) of bovine filarial worms to varying degrees. Some of the compounds though effected the motility and MTT reduction potential of filarial worms Brugia malayi, however, little microfilaricidal and macrofilaricidal were noted with compounds at 50mg/kg oral dose. Compounds 6, 16 and 17 were evaluated also for in vivo activity. 相似文献
7.
Reaction of substrates containing primary amines with rhodamine 2'-esters cleanly produces fluorescent rhodamine 2'-amide conjugates at ambient temperature. Only primary amines react with the esters under these conditions. Chemoselectivity can thus be achieved in substrates containing different types of amines. 相似文献
8.
A general methodology for the selective derivatization of amines, to enable quantitation by high pressure liquid chromatography with electrochemical detection, is presented. N-Hydroxysuccinimide active esters present in large excess are suitably mild acylating agents to derivatize selectively trace quantities of amines for electrochemical detection. The 2 separate problems of extraction yield and detectability can be solved by this derivatization method. Due to its lipophilicity the resulting N-acylated amine, as demonstrated with serotonin, is extracted efficiently into organic solvents during sample preparation for chromatography. Moreover, the acyl group introduced can be designed to be electroactive, thus extending the procedure to amines not readily oxidized, e.g., histamine and phenylethylamine. 相似文献
9.
A simple three-component chiral derivatization protocol for determining the enantiopurity of chiral primary amines by 1H NMR spectroscopic analysis is described here. The method involves condensation of the amines with 2-formylphenylboronic acid and enantiopure 1,1'-bi-2-naphthol. This approach affords a mixture of diastereoisomeric iminoboronate esters whose ratio can be determined by the integration of well-resolved diastereotopic resonances in their 1H NMR spectra, thus enabling the enantiopurity of the parent amine to be determined easily. The protocol, as described, takes less than 90 min to complete. 相似文献
10.
Ligands containing amino or hydroxyl groups were converted to their corresponding activated N-hydroxysuccinimidyl carbamate and carbonate by reaction with disuccinimidyl carbonate (DSC). The latter reagents can be used for the group-specific modification of primary amines as an alternative to the widespread usage of N-hydroxysuccinimide esters. Biotin and 2,4-dinitrophenyl (DNP) derivatives were used as examples to demonstrate the approach. Biotin and DNP were each extended by attaching two different spacer arms, carrying either a hydroxyl group or a primary amine as terminal functions. The latter were then activated via their conversion to N-hydroxysuccinimide carbonates and carbamates, respectively. The usefulness of these reagents for protein modification was investigated. The modified proteins obtained exhibited similar stability and activity characteristics compared to those modified with active N-hydroxysuccinimdyl esters. The activation of hydroxy- or amino-terminating compounds with DSC represents a general method that can be applied to any ligand which contains these functional groups for its covalent coupling to amines. 相似文献
11.
Non-conventional hydrolase chemistry: amide and carbamate bond formation catalyzed by lipases 总被引:2,自引:0,他引:2
Gotor V 《Bioorganic & medicinal chemistry》1999,7(10):2189-2197
Biocatalysis in nonaqueous media is becoming increasingly important in organic synthesis. Lipases are the most used enzymes, especially in transesterification reactions. However, in the last years the amidation reaction catalyzed by lipases has also been shown to be a useful tool for the organic chemists. In this review, we discuss the possibilities of the enzymatic aminolysis and ammonolysis reactions for the preparation of different amides and for the resolution of esters, amines and aminoalcohols. The enzymatic alkoxycarbonylation of amines opens a new way for the synthesis of chiral carbamates. 相似文献
12.
The effect of quercetin on the mutagenicity of 32 kinds of aromatic amines and their acetamides were investigated using Salmonella typhimurium TA98 with a mammalian metabolic activation system (S9 mix). Quercetin enhanced the mutagenicity of the tricyclic aromatic amines (aminofluorene, aminoanthracene and aminophenanthrene) and their acetamides by 1.2-5.9-fold. Whereas, quercetin depressed the mutagenicity of aniline derivatives, biphenyl derivatives, and bi- and tetra-cyclic amino derivatives. The modulation of mutagenicity of Trp-P-1, Trp-P-2, Glu-P-1 and Glu-P-2 (heterocyclic amines) by quercetin were liable to be affected by the content of S9 in the S9 mix. It seems that quercetin does not have the same effect as norharman, because quercetin did not enhance the mutagenicity of aniline. It is suggested that the modulation of the mutagenicity of aromatic amines and acetamides is caused by the modulation of the balance between the mutagenic activation and inactivation in the metabolism of these amines and acetamides in the presence of quercetin. In this modulation, quercetin may participate through its effects on the promotion of N-hydroxylation and the inhibition of arylhydroxylation and transacylation. The presence of tricyclic aromatic rings of amines and acetamides is a structural requirement for the mutagenicity enhancement by quercetin. 相似文献
13.
Analysis of Biogenic Amines in Bovine Retina by Gas Chromatography-Negative Ion Chemical Ionisation Mass Spectrometry 总被引:1,自引:1,他引:0
R. G. Macfarlane S. C. Macleod J. M. Midgley D. G. Watson 《Journal of neurochemistry》1989,53(6):1731-1736
Biogenic amines in bovine retina have been identified and quantified by an extraction-derivatisation procedure involving their reaction with 3,5-di(trifluoromethyl)benzoyl chloride (DTFMBCl) in the aqueous phase followed by extraction into an organic solvent, hydrolysis of phenolic esters, and conversion of free hydroxyl groups to trimethylsilyl ethers. Subsequent analysis of these DTFMB-trimethylsilyl derivatives by gas chromatography-negative ion chemical ionisation mass spectrometry revealed that the molecular ion carried most (greater than 60%) of the ion current, which made the method highly specific and gave a potential limit of detection below the picogram level. This method establishes unequivocally that the principal amines in bovine retina are p-tyramine, dopamine, and 5-hydroxytryptamine. 相似文献
14.
The total fractions of choline esters have been isolated from different parts of Sinapis alba. 4-Hydroxybenzoylcholine has been identified and found to be one of the quantitatively dominating choline esters in seed extracts of S. alba. The identity of the new natural product has been confirmed by comparison with synthetic reference compounds. Several different choline esters are present in this plant but in extracts of seedlings, leaves, and inflorescences they are not so quantitatively dominating as in seeds. The modified ion-exchange technique applied appeared to be an efficient tool in the isolation and separation of choline esters and amines from other types of phenolic plant constituents. 相似文献
15.
A range of cross-linked enzyme aggregates (CLEAs) was prepared from commercially available aminoacylase I. Results from three test reactions showed that aminoacylase does not possess aminolysis or alcoholysis activity, both previously ascribed to this enzyme. This result was confirmed using aminoacylase purified by chromatographic techniques, which leads us to conclude that the previously observed acylations of esters and amines is due to other enzymes present as impurities in the crude aminoacylase I. 相似文献
16.
The interactions of long chain (greater than C7), alkyl compounds with tightly coupled, beef heart submitochondrial particles (SMP) have been investigated with respect to their effects upon respiratory chain-linked electron transfer and energy coupling capacity. Long chain alkyl alcohols, amines, free fatty acids, and methyl esters exhibit a general uncoupling effect, with stimulation of the succinate oxidase activity but inhibition of the NADH oxidase, in SMP. The degree of effectiveness is dependent on the nature of the functional group and the length of the alkyl chain. Submitochondrial particles depleted of F1 and the F1-inhibitor protein are similarly affected. Subsequent treatment with bovine serum albumin reverses the effects of free fatty acids and results in partial recovery of activity with alkyl amines, alcohols, and methyl esters. Differences between the effects of these alkyl compounds and those of sodium dodecyl sulfate, deoxycholate, palmitoyl carnitine, and palmitoyl CoA rule out detergent-like action as the explanation for these observations. These data suggest that specific lipophilic interactions with the membrane, modulated by the nature of the functional group, are responsible for the effects of these compounds on the energy transducing system of SMP. Analyses of the reduction kinetics of the cytochromes indicate that the sites of interaction of these compounds with the inner mitochondrial membrane are associated with the primary dehydrogenase of complex I and energy coupling site 2; alkyl amines possess an additional site of interaction in the region of complex III. 相似文献
17.
Polymer-bound N-hydroxysuccinimide esters of 1-pyrenebutyric acid, 6-carboxyfluorescein diacetate, and biotin were efficiently prepared. Column-free fluorescent- and biotin-labeling reactions of various amines using these resins were successfully demonstrated. 相似文献
18.
Liang Lu Xiaorong Gu Li Hong James Laird Keeve Jaffe Jaewoo Choi John Crabb Robert G. Salomon 《Bioorganic & medicinal chemistry》2009,17(21):7548-7561
Protein modifications in which the ε-amino group of lysyl residues is incorporated into a 2-(ω-carboxyethyl)pyrrole (CEP) are mediators of age-related macular degeneration (AMD). They promote both angiogenesis into the retina (‘wet AMD’) and geographic retinal atrophy (‘dry AMD’). Blood levels of CEPs are biomarkers for clinical prognosis of the disease. To enable mechanistic studies of their role in promoting AMD, for example, through the activation of B- and T-cells, interaction with receptors, or binding with complement proteins, we developed an efficient synthesis of CEP derivatives, that is especially effective for proteins. The structures of tryptic peptides derived from CEP-modified proteins were also determined. A key finding is that 4,7-dioxoheptanoic acid 9-fluorenylmethyl ester reacts with primary amines to provide 9-fluorenylmethyl esters of CEP-modified proteins that can be deprotected in situ with 1,8-diazabicyclo[5.4.0]undec-7-ene without causing protein denaturation. The introduction of multiple CEP-modifications with a wide variety of CEP:protein ratios is readily achieved using this strategy. 相似文献
19.
This protocol details the most commonly used nuclear magnetic resonance (NMR)-based method for deducing the configuration of otherwise unknown stereogenic, secondary carbinol (alcohol) centers (R1R2CHOH (or the analogous amines where OH is replaced by NH2)). This 'Mosher ester analysis' relies on the fact that the protons in diastereomeric alpha-methoxy-alpha-trifluoromethylphenylacetic acid (MTPA) esters (i.e., those derived from conjugation of the carbinol under interrogation with MTPA) display different arrays of chemical shifts (deltas) in their 1H NMR spectra. The protocol consists of the following: (i) preparation of each of the diastereomeric S- and R-MTPA esters and (ii) comparative (Delta delta(SR)) analysis of the 1H NMR spectral data of these two esters. By analyzing the sign of the difference in chemical shifts for a number of analogous pairs of protons (the set of Delta delta(SR) values) in the diastereomeric esters (or amides), the absolute configuration of the original carbinol (or amino) stereocenter can be reliably deduced. A typical Mosher ester analysis requires approximately 4-6 h of active effort over a 1- to 2-d period. 相似文献
20.
N-hydroxysuccinimide (NHS) esters are derivatizing agents that target primary amine groups. However, even a small molar excess of NHS may lead to acylation of hydroxyl-containing amino acids as a side reaction. We report a straightforward method for the selective removal of ester-linked acyl groups after NHS ester-mediated acylation of peptides and proteins. It is based on incubation in a boiling water bath and does not require a change in pH or the addition of chemicals. It is therefore particularly suited for proteomics samples that are often small in volume and contain low amounts of peptides. The method was optimized and evaluated with two peptides and one protein that were acetylated at a high excess of NHS-acetate. While the large molar excess resulted in complete acylation of all primary amines, hydroxyl-containing amino acids were shown to react as well. By incubating the peptide or protein solutions in a boiling water bath, acetyl-ester bonds were hydrolyzed, whereas acetyl-amide bonds remained stable. The reaction was also performed in 6 M guanidine-HCl, which prevented protein precipitation. In conclusion, the present method allows the selective acylation of primary amines by NHS esters and constitutes a valuable alternative to the treatment with hydroxylamine under alkaline conditions. 相似文献