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At least 91 records · Page 5Linked to original sources
PubMed1993

Dimethyl-acetamide as a cryoprotectant for rainbow trout spermatozoa.

Dimethyl-acetamide was evaluated as a cryoprotectant for rainbow trout (Oncorhynchus mykiss ) semen on the basis of motility, percentage of dead spermatozoa as determined by fluorometry, and fertility of frozen-thawed spermatozoa. Dimethyl-acetamide performed significantly better (P<0.05) than the conventional cryoprotectant, dimethyl sulfoxide, by all evaluation methods. An extender comprised of 0.137 M NaCl, 0.011 M KCl, 0.004 M Na(2)HPO(4) 7H(2)O, 7.5 g/l L-alpha-lecithin and 10 % DMA showed promise for cryopreserving rainbow trout spermatozoa. Future evaluation of new extenders should be carried out by several in vitro techniques and fertility measurements to present a complete assessment of an extender's ability to cryopreserve sperm cells.

Journal Article↗
PubMed2004

A validated chiral LC method for the enantioselective analysis of Levetiracetam and its enantiomer R-alpha-ethyl-2-oxo-pyrrolidine acetamide on amylose-based stationary phase.

A new, simple chiral HPLC method was developed for the enantiomeric separation of Levetiracetam, [(S)-alpha-ethyl-2-oxo-pyrrolidine acetamide], an antiepileptic drug in pharmaceutical formulations and in bulk materials. Enantiomeric separation was achieved on a chiralpak AD-H column using a mobile phase consisting of hexane and isopropanol in the ratio (90:10, v/v) at a flow rate of 1.0 ml/min. The resolution between the enantiomers was found to be not less than 7 in the optimized method. Interestingly, unwanted enantiomer, namely R-alpha-ethyl-2-oxo-pyrrolidine acetamide ((R)-enantiomer), was eluted prior to its mirror image in the developed method. The developed method was found to be selective in the presence of related impurities of Levetiracetam, namely N-(1-carbamoyl-propyl)-4-chloro-butyramide (Imp-1) and 1-ethyl-2-oxo-1-pyrrolidine acetic acid (Imp-2), and also under exposed conditions of UV light and 60 degrees C. The limit of detection (LOD) and limit of quantification (LOQ) of (R)-enantiomer were found to be 900 and 2250 ng/ml, respectively, for 10 microl injection volume. The method precision for (R)-enantiomer at limit of quantification level was within 8% R.S.D. Calibration curve for (R)-enantiomer was linear over the studied ranges (2250-9000 ng) with correlation coefficient greater than 0998. The active pharmaceutical ingredient was extracted from its finished dosage form (tablet) using isopropanol. The percentage recoveries of (R)-enantiomer were ranged from 94.2 to 102.6 and from 93.5 to 104.1 in spiked bulk and formulation samples of Levetiracetam, respectively. Levetiracetam sample solution and mobile phase are found to be stable for at least 48 h. The developed method was found to be rugged and robust. The proposed method was found to be suitable and accurate for the quantitative determination of (R)-enantiomer in bulk drugs and commercial formulations. Chiralcel OD-H column can also be used as an alternative column for the above purpose.

Amides↗
PubMed2000

Enantioselective analysis of levetiracetam and its enantiomer R-alpha-ethyl-2-oxo-pyrrolidine acetamide using gas chromatography and ion trap mass spectrometric detection.

A gas chromatographic-mass spectrometric method was developed for the enantioselective analysis of levetiracetam and its enantiomer (R)-alpha-ethyl-2-oxo-pyrrolidine acetamide in dog plasma and urine. A solid-phase extraction procedure was followed by gas chromatographic separation of the enantiomers on a chiral cyclodextrin capillary column and detection using ion trap mass spectrometry. The fragmentation pattern of the enantiomers was further investigated using tandem mass spectrometry. For quantitative analysis three single ions were selected from the enantiomers, enabling selected ion monitoring in detection. The calibration curves were linear from 1 microM to 2 mM for plasma samples and from 0.5 mM to 38 mM for urine samples. In plasma and urine samples the inter-day precision, expressed as relative standard deviation was around 10% in all concentrations. Selected ion monitoring mass spectrometry is suitable for quantitative analysis of a wide concentration range of levetiracetam and its enantiomer in biological samples. The method was successfully applied to a pharmacokinetic study of levetiracetam and (R)-alpha-ethyl-2-oxo-pyrrolidine acetamide in a dog.

Animals↗
PubMed2001

Potent nonpeptide GnRH receptor antagonists derived from substituted indole-5-carboxamides and -acetamides bearing a pyridine side-chain terminus.

A pyridine side-chain terminus has been incorporated into the indole-5-carboxamide and indole-5-acetamide series of GnRH antagonists. Potent activity was observed in binding and functional assays. Certain branched or cyclic tertiary amides were identified as preferred in each series. Alkylation of the side-chain secondary amine had generally unfavorable effects. Variations of the gem-dialkyl substituents in the indole-5-acetamide series were also investigated.

Amides↗
PubMed2001

Anti-influenza virus activities of 2-alkoxyimino-n-(2-isoxazolin-3-ylmethyl)acetamides.

A series of 2-alkoxyimino-N-(2-isoxazolin-3-ylmethyl)acetamides and related compounds were synthesized and their antiviral activities against human influenza A virus were assessed. Studies of the structure-activity relationships revealed the strongest antiviral activity when position-5 of the isoxazoline ring was substituted with a tert-butyl group. When the alkoxyimino moiety was substituted with a methyl, ethyl, isopropyl or allyl group, good antiviral activity was obtained. Among the geometrical isomers at the oxime moiety, the E-isomers were more active than the Z-isomers. Among the compounds examined, (E)-2-allyloxyimino-2-cyano-N-(5-tert-butyl-2-isoxazolin-3-ylmethyl)acetamide (1j) was the most active inhibitor with an EC(50) of 3 microg/mL in vitro.

Antiviral Agents↗
PubMed2001

New antimetastatic hypoxic cell radiosensitizers: design, synthesis, and biological activities of 2-nitroimidazole-acetamide, TX-1877, and its analogues.

We designed, based on the molecular orbital (MO) calculation, synthesized, and evaluated the biological activities of the new antimetastatic hypoxic cell radiosensitizer, 2-nitroimidazole-acetamide, TX-1877, and its analogues. Each analogue has an electron-affinic imidazole group, an acetamide group and a certain hydrophilic group to control its biological effect, toxicity, and pharmacokinetics. In in vitro radiosensitization assay, most TX-1877 analogues, which have an electron affinity (EA) of more than 0.9 eV and partition coefficient (P) of more than 0.021, showed satisfactory enhancement ratios (ER > 1.60) at doses of I mM. On the other hand, imidazole analogues, such as TX-1908 (EA = 0.67 eV), TX-1910 (EA = -0.34 eV) and TX-1931 (EA = -0.37 eV), which have low electron affinities, had an ER of 1.31 or less. TX-1877 and KIN-806 effectively inhibited tumor regrowth when administered with irradiation in vivo at a dose of 0.4 mg/g. Tumor lung metastasis was inhibited by treatment with either TX-1877 or KIN-806 without irradiation at a dose of 0.4 mg/g. TX-1877 reduced markedly the mean number of metastatic lung nodules in comparison with KIN-806. Moreover, TX-1877 and KIN-806 enhanced macrophage and helper T lymphocyte infiltration for 3 weeks after drug treatment. TX-1877 shows a high EA value and has the C2 of HOMO localizing on N-methylamide and the C2 of LUMO localizing on 2-nitroimidazole group. The MO data might be useful for designing a bifunctional hypoxic cell radiosensitizer. TX-1877 and its analogues are potential antimetastatic hypoxic cell radiosensitizers, which would improve the efficiency of radiotherapy and quality of life in cancer treatment.

Animals↗
PubMed2001

2-(2-Oxo-1,4-dihydro-2H-quinazolin-3-yl)- and 2-(2,2-dioxo-1,4-dihydro-2H-2lambda6-benzo[1,2,6]thiadiazin-3-yl)-N-hydroxy-acetamides as potent and selective peptide deformylase inhibitors.

Potent, selective, and structurally new inhibitors of the Fe(II) enzyme Escherichia coli peptide deformylase (PDF) were obtained by rational optimization of the weakly binding screening hit (5-chloro-2-oxo-1,4-dihydro-2H-quinazolin-3-yl)-acetic acid hydrazide (1). Three-dimensional structural information, gathered from Ni-PDF complexed with 1, suggested the preparation of two series of related hydroxamic acid analogues, 2-(2-oxo-1,4-dihydro-2H-quinazolin-3-yl)-N-hydroxy-acetamides (A) and 2-(2,2-dioxo-1,4-dihydro-2H-2lambda(6)-benzo[1,2,6]thiadiazin-3-yl)-N-hydroxy-acetamides (B), among which potent PDF inhibitors (37, 42, and 48) were identified. Moreover, two selected compounds, one from each series, 36 and 41, showed good selectivity for PDF over several endoproteases including matrix metalloproteases. However, these compounds showed only weak antibacterial activity.

Amidohydrolases↗
PubMed1990

Chemical and biochemical studies of 2-propynylpyrrolidine derivatives. Restricted-rotation analogues of N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide (BM-5).

A series of optically pure 2-[substituted-3-aminopropynyl]pyrrolidine derivatives, which are restricted-rotation analogues of the muscarinic agent N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide (BM-5, compound 1), have been prepared from d- and l-proline. The compounds when tested in a series of in vitro muscarinic assays [[3H]CD (cortex), [3H]QNB (cortex), [3H]PZ (cortex), [3H]QNB (heart), [3H]QNB + GppNHp (heart)] were found to have weaker muscarinic properties than compound 1. The decrease in affinity was attributed to the increased size of the molecule resulting from the addition of a methylene group to form the pyrrolidine ring. The use of optically active compounds provided a more detailed examination of the complex pharmacological effects of the flexible muscarinic agent 1. The R enantiomers in the acetamide derivatives 12b, 12d, and 12f had a 5-10-fold greater affinity for the muscarinic receptor than the corresponding S enantiomers. A 5-fold difference or less found in the (R)- and (S)-carbamate derivatives 9, 15, and 16 suggested close overlap of the two enantiomers in the receptor binding domain. The affinity differences found in the enantiomeric acetamido derivatives when compared to those of the carbamate analogues may be the result of limited rotation of the acetamido group.

Animals↗
PubMed1996

Indole inhibitors of human nonpancreatic secretory phospholipase A2. 2. Indole-3-acetamides with additional functionality.

As reported in our previous paper, a series of indole-3-acetamides which possessed potency and selectivity as inhibitors of human nonpancreatic secretory phospholipase A2(hnps-PLA2) was developed. The design of these compounds was based on information derived from x-ray crystal structures determined for complexes between the enzyme and its inhibitors. We describe here the further implementation of this structure-based design strategy and continued SAR development to produce indole-3-acetamides with additional functionalities which provide increased interaction with important residues within the enzyme active site. These efforts led to inhibitors with substantially enhanced potency and selectivity.

Crystallography, X-Ray↗
PubMed1989

Molecular cloning of a gene for indole-3-acetamide hydrolase from Bradyrhizobium japonicum.

A pLAFR1 cosmid genomic library of wild-type Bradyrhizobium japonicum J1063 was constructed. A cosmid clone designated pBjJ4, containing a 26-kilobase (kb) DNA insert, was identified as being able to confer the ability to convert alpha-naphthaleneacetamide acid on B. japonicum J1B7 Rifr, which cannot perform this conversion. The gene coding for the enzyme that converts alpha-naphthaleneacetamide to alpha-naphthaleneacetic acid was localized in the 3.5-kb region of pBjJ4 by recloning in plasmid pSUP202. The gene coding for the enzyme was also mapped by Tn5 insertion mutagenesis to a region of ca. 2.3 kb. When the gene was placed behind the lacZ promoter and used to transform Escherichia coli, a high level of expression of indole-3-acetamide hydrolase activity was found. Since there have been no reports of this activity in E. coli, we have thus confirmed that the gene cloned here is a structural gene for indole-3-acetamide hydrolase and have designated it as the bam (Bradyrhizobium amidehydrolase) gene. Southern hybridization with the central region of the bam gene indicated that a high degree of similarity exists among the bam gene, the iaaH gene from Pseudomonas savastonoi, and the tms-2 gene from Agrobacterium tumefaciens. The result suggests that there is a common origin for the gene that encodes the enzyme that catalyzes the biosynthesis of indoleacetic acid.

Amidohydrolases↗
PubMed1976

Increased susceptibility to carcinoma of the liver in rats with one kidney ingesting N-4-(4'-fluorobiphenyl) acetamide.

The role of the kidneys in hepatic carcinogenesis was studied in inbred Buffalo strain male rats ingesting 0.04% N-4-(4'-flourobiphenyl) acetamide in the diet. Experimental groups were made up of male rats with both kidneys intact and male rats with the left kidney removed. The incidence of carcinomas of the liver and the number of rats with large carcinomas, multiple carcinomas, poorly differentiated and undifferentiated carcinomas, and metastases were greater in rats with a uninephrectomy. Apparently the animals with one kidney removed were unable to secrete the metabolites of N-4-(4'-fluorobiphenyl) acetamide as readily as the rats with both kidneys.

Aminobiphenyl Compounds↗
PubMed2004

Synthesis of new 2-[1(2H)-phthalazinon-2-yl]acetamide and 3-[1(2H)-phthalazinon-2-yl]propanamide derivatives as antinociceptive and anti-inflammatory agents.

As a consequence of our ongoing studies on heterocyclic compounds for new antinociceptive and anti-inflammatory agents bearing lactam functional group, new 2-[1(2H)-phthalazinon-2-yl]acetamide and 3-[1(2H)-phthalazinon-2-yl]propanamide derivatives have been synthesized. Among the compounds synthesized, compound (4e) was found the most active derivative in terms of antinociceptive and anti-inflammatory activities, without gastric lesions and bleeding at the given dose.

Acetamides↗
PubMed1981

The effect of hexamethylene-bis-acetamide on multiparameter analysis of Friend leukemia cells.

Friend leukemia cells were induced to differentiate by hexamethylene-bis-acetamide (HMBA). The relationship between cell growth cell volume distribution, fluorescence intensity and fluorescence anisotropy of the membrane probe 1,6 diphenyl 1,3,5 hexatriene (DPH) was analyzed in differentiated and undifferentiated cells with the aid of the fluorescence activated cell sorter (FACS II). The induction of a differentiated state was associated with a decrease in cell volume and an increase of fluorescence anisotrophy. The inhibition of this induction by dexamethasone prevented the decrease of cell volume without affecting the increase of fluorescence anisotropy. We conclude therefore that the high degree of anisotropy is not correlated to the differentiated state nor with the volume of the cells.

Acetamides↗
PubMed1978

Rearrangement of N-benzyl-2-cyano-2-(hydroxyimino)acetamide.

The reduction of N-benzyl-2-cyano-2-(hydroxyimino)acetamide resulted in the formation of N-benzyl-1,2-ethanediamine and N-benzyl-N'-methyl-1,2-ethanediamine in approximately an equimolar ratio. The formation of the two unexpected products is explained by the migration of a cyano group in a Beckmann-type rearrangement.

Acetamides↗
PubMed2006

Antiangiogenic effect of 2-benzoyl-phenoxy acetamide in EAT cell is mediated by HIF-1alpha and down regulation of VEGF of in-vivo.

Benzophenones and its analogues are known for wide range of biological properties. Synthetic benzophenone analogue 2-benzoyl -phenoxy acetamide (BP-1) is proven to be potent antitumor and proapoptotic activity against EAT cells in-vivo. In the present report, we studied the antiangiogenic effect of BP-1 in EAT cells induced angiogenesis. Treatment with BP-1 in-vivo was demonstrated by the down regulation of the secretion of VEGF from EAT cells and inhibition of blood vessels formation indicating the potential angioinhibitory effect of BP-1 in EAT cells. HIF-1alpha protein, a transcription factor known to be key a regulator in hypoxia-induced angiogenesis was also down regulated by BP-1. Our findings indicated that, HIF-1alpha nuclear sequestration is repressed by BP-1 through inhibition of nuclear translocation. We postulate that diminished HIF-1alpha nuclear presence and activity in BP-1 treated EAT cells could be responsible for decreased VEGF expression and antiangiogenic effects.

Acetamides↗
PubMed1976

Energetics of the deformation of a peptide unit. Semi-empirical molecular orbital and ab initio study of N-methyl acetamide and N-acetyl-L-alanine N-methyl amide.

The problem of non-planarity of peptide unit has been investigated using N-methyl acetamide as a theoretical model. A semi-empirical molecular orbital method: Iterative Extended Hückel Theory viz. IEHT/2 (Adams S. (1974) Doctoral dissertation, State University of New York at Buffalo, U.S.A.) and non-empirical abinitio method with minimal basis set, STO-3G (Hehre, W.J., Stewart, R.F. and Pople, J.A. (1969) J. Chem. Phys. 51, 2657-2664) were used to probe the energetics of the distortion of a planar peptide unit. Distortion of one of the peptide units in a dipeptide, N-acetyl-L-alanine N-methyl amide has also been investigated using abinitio method. The studies amply demonstrate the possibility of the existence of a non-planar peptide unit. Distortion of about 10-15 degrees is predicted to bring about very small loss in energy. The results are substantiated by results from experimental studies.

Acetamides↗