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PubMed1986

The efficacy of acetamide for the treatment of experimental Dichapetalum cymosum (gifblaar) poisoning in sheep.

High mortality of livestock is caused annually by the plant, Dichapetalum cymosum (gifblaar), in the Northern Transvaal. So far no therapeutic measures have been developed for the prevention or treatment of this poisoning. In this presentation, the efficacy of acetamide as therapy for experimental gifblaar poisoning was tested in 18 sheep. When 2.5-5 g/kg of acetamide was dosed to sheep at various intervals before and sometimes after the administration of 5 g/kg of gifblaar, 1 out of 5 survived, compared with 0 out of 2 controls. Dosing of 2 g/kg of acetamide before and/or simultaneously with or after 1 g/kg gifblaar prevented mortality as 5 out of 5 treated sheep survived compared with none of the 5 controls. The experiments indicate that acetamide has demonstrable therapeutic value as an antidote for the prevention of experimental gifblaar poisoning in sheep. Further investigations should determine the feasibility and applicability of these findings under field conditions in sheep and cattle.

Acetamides↗

PubMed1994

Biotransformation of the organic nitrate trans-N-(4-nitroxycyclohexyl)acetamide in dogs.

The biotransformation of BM 12.1307 (trans-N-(4-nitroxycyclohexyl)acetamide, CAS 137291-91-3) in the dog was examined after oral and intravenous administration. For that purpose, the organic nitrate was synthesized as radioactive [14C]- and as [13C]-labeled compounds. The defined isotopic mixture was administered to the dogs. Within the examined period of 168 h, the elimination of BM 12.1307 and its metabolites via urine and feces amounted to 76.5% after oral application, and to 80.7% of the applied dose after intravenous application. The major amount of radioactivity was eliminated via urine (69.4% and 73.6% of the dose, respectively), whereas the fecal elimination was found to be negligible. Investigations of the urinary samples showed that the drug is metabolized to a high percentage trans-N-(4-Hydroxycyclohexyl) acetamide is the main metabolite; 73% of the radioactive compounds (after p.o.-administration and 69% after intravenous application could be identified as the alcohol of BM 12.1307; the amounts of the drug totalled 9% and 13%, respectively. The quantitative determination of BM 12.1307 in urine and plasma was performed by gas chromatography; the amount of the main metabolite excreted in urine was determined by high-pressure liquid chromatography. Trans-N-(4-hydroxycyclohexyl)-acetamide, N-(4-oxocyclohexyl)acetamide, and 3-acetamido-7-oxa-bicyclo [4.1.0]heptane were formed as metabolites. For the identification and characterization of the possible metabolic structures, these compounds were synthesized and used in comparison with the detected drugs.

Acetamides↗

PubMed1977

Polyamine metabolism I: Synthesis of dansyl derivatives of N-(monoaminoalkyl)- and N-(polyaminoalkyl)acetamides and elucidation in urine of a cancer patient.

The dansyl derivatives of N-(monoaminoalkyl)- and N-(polyaminoalkyl)acetamides were synthesized and unequivocally characterized. TLC of the dansyl derivatives obtained from human urine indicated the presence of N-[3-[(4-aminobutyl)amino]propyl]acetamide (N1-acetylspermidine, N-[4-[(3-aminopropyl)amino]butyl]acetamide (N8-acetylspermidine), and N-(4-aminobutyl)acetamide (N-acetylputrescine) in appreciable amounts. The dansyl derivatives of N1-acetylspermidine, N8-acetylspermidine, and N-acetylputrescine were isolated and purified using various chromatographic methods. The mass spectra of these compounds were similar to those of authentic samples, which confirmed the identity of these compounds and established the presence of N8-acetylspermidine as well as N1-acetylspermidine and N-acetylputrescine in human urine.

Carcinoma, Hepatocellular↗

PubMed2003

Molecular cloning and characterization of an amidase from Arabidopsis thaliana capable of converting indole-3-acetamide into the plant growth hormone, indole-3-acetic acid.

Acylamidohydrolases from higher plants have not been characterized or cloned so far. AtAMI1 is the first member of this enzyme family from a higher plant and was identified in the genome of Arabidopsis thaliana based on sequence homology with the catalytic-domain sequence of bacterial acylamidohydrolases, particularly those that exhibit indole-3-acetamide amidohydrolase activity. AtAMI1 polypeptide and mRNA are present in leaf tissues, as shown by immunoblotting and RT-PCR, respectively. AtAMI1 was expressed from its cDNA in enzymatically active form and exhibits substrate specificity for indole-3-acetamide, but also some activity against L-asparagine. The recombinant enzyme was characterized further. The results show that higher plants have acylamidohydrolases with properties similar to the enzymes of certain plant-associated bacteria such as Agrobacterium-, Pseudomonas- and Rhodococcus-species, in which these enzymes serve to synthesize the plant growth hormone, indole-3-acetic acid, utilized by the bacteria to colonize their host plants. As indole-3-acetamide is a native metabolite in Arabidopsis thaliana, it can no longer be ruled out that one pathway for the biosynthesis of indole-3-acetic acid involves indole-3-acetamide-hydrolysis by AtAMI1.

Amidohydrolases↗

PubMed1993

Stimulation of brain steroidogenesis by 2-aryl-indole-3-acetamide derivatives acting at the mitochondrial diazepam-binding inhibitor receptor complex.

The 2-aryl-indole-3-acetamide derivatives, 2-hexyl-indole-3-acetamide (FGIN-1-27) and 2-hexyl-indole-3-acetamide-N-benzene-tricarboxylic acid (FGIN-1-44) displaced [3H]1-(2-chlorophenyl)-N-methyl-N-(1- methylpropyl)-3-isoquinoline-carboxamide([3H]PK 11195) and [3H]4-chlorodiazepam ([3H]4'CD) from binding sites located on the rat brain mitochondrial DBI receptor complex (MDRC) with Ki values in the nanomolar range. Both 2-aryl-indole-3-acetamide derivatives acted as agonists at the MDRC and thereby stimulated the rate of pregnenolone synthesis in isolated rat brain mitochondria; this effect was inhibited by PK 11195, an MDRC ligand that does not possess steroidogenic activity. FGIN-1-27 and FGIN-1-44 failed to bind to other transmitter receptors, including gamma-aminobutyric-A receptors. When administered orally to rats, both FGIN-1-27 and FGIN-1-44 reduced fear of novelty in the elevated plus maze test. This action was prevented by PK 11195, but not by flumazenil. FGIN-1-44, which was rapidly converted to FGIN-1-27 in the rat brain, was 3 to 4 times more potent than FGIN-1-27 in reducing fear of novelty because of its greater bioavailability. FGIN-1-27 increased the brain pregnenolone content in adrenalectomized-castrated rats pretreated with trilostane (in order to prevent metabolism of pregnenolone to progesterone). This increase was blocked by pretreatment with PK 11195. Although FGIN-1-27 and FGIN-1-44 increased the corticosterone concentration in adrenal glands and plasma of hypophysectomized rats in a PK 11195-sensitive manner, both drugs failed to increase adrenal steroidogenesis in sham-operated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗

PubMed1975

Membrane proteins and urea and acetamide transport in the human erythrocyte.

Previous studies have shown that urea and acetamide traverse the erythrocyte membrane by way of facilitated diffusion. The nature of this selective pathway is unknown. The present studies investigate the effects of proteolytic enzymes and crosslinking agents on amide transport. Cleavage of the erythrocyte membrane surface by pronase or trypsin had no effect on urea and acetamide permeability or inhibition by phloretin. These findings suggest that the sialoglycopeptide segment of the sialoglycoproteins is not critical to urea and acetamide transport. In addition, extensive crosslinking of membrane proteins with glutaraldehyde had no effect on amide transport in the absence or presence of phloretin.

Acetamides↗

PubMed1991

2-(3,4-Dichlorophenyl)-N-methyl-N-[2-(1-pyrrolidinyl)-1-substituted- ethyl]-acetamides: the use of conformational analysis in the development of a novel series of potent opioid kappa agonists.

This paper describes the synthesis of a series of N-[2-(1-pyrrolidinyl)ethyl]acetamides (1), methylated at C1 and/or C2 of the ethyl linking group, and their biological evaluation as opioid kappa agonists. Conformational analysis of corresponding desaryl analogues 2 suggested that only those compounds capable of occupying an energy minimum close to that of the known kappa agonist N-[2-(1-pyrrolidinyl)cyclohexyl] acetamide U-50488 might possess kappa agonist properties. Starting from chiral amino acids, other alkyl and aryl substituents were introduced at C1 of the ethyl-linking moiety, giving compounds capable of adopting the same conformation as U-50488. The most potent of these, 2-(3,4-dichlorophenyl)-N-methyl-N-[(1S)-1-phenyl-2-(1-pyrrolidinyl)ethyl] acetamide (8), was 146-fold more active than U-50488 in vitro in the mouse vas deferens model and exhibited potent naloxone-reversible analgesic effects (ED50 = 0.004 mg/kg sc) in an abdominal constriction model.

Acetamides↗

PubMed1991

Structure/activity studies related to 2-(3,4-dichlorophenyl)-N-methyl-N-[2-(1-pyrrolidinyl)-1-substituted- ethyl]acetamides: a novel series of potent and selective kappa-opioid agonists.

This paper describes the synthesis of a series of N-[2-(1-pyrrolidinyl)ethyl]acetamides 1, variously substituted at the carbon adjacent to the amide nitrogen (C1), and related analogues, together with their biological evaluation as opioid kappa agonists. In the first part of the study, the variants in N-acyl, N-alkyl, and amino functions were explored when the substituent at C1 was 1-methylethyl and the optimum was found to be exemplified by 2-(3,4-dichlorophenyl)-N-methyl-N-[(1S)-1-(1-methylethyl)-2- (1-pyrrolidinyl)ethyl]acetamide (13). Subsequently, racemic or chiral amino acids were used to introduce other alkyl and aryl substituents at C1 of the ethyl linking moiety. A series of potent compounds, bearing substituted-aryl groups at C1, were discovered, typified by 2-(3,4-dichloro-phenyl)-N-methyl-N-[(1R,S)-1-(3-aminophenyl)-2-(1- pyrrolidinyl)ethyl]acetamide (48), which was 5-fold more active as the racemate than 13 in vitro and exhibited potent naloxone-reversible analgesic effects (ED50 = 0.04 mg/kg sc) in a mouse abdominal constriction model.

Acetamides↗

PubMed2003

Synthesis and local anaesthetic activity of 2-substituted-N-(2-diethylaminoethyl)-acetamides.

The synthesis of 2-substituted-N-(2-diethylaminoethyl)acetamide oxalates (6a, 6b) and the evaluation of their in vivo local anaesthetic activities are described. The compounds 6a and 6b were obtained starting from 4-acetamidophenol and 1-naphthol, respectively. The in vivo local anesthetic activity was evaluated by infiltration anaesthesia, sciatic nerve block and corneal anaesthesia models. N-(2-Diethylaminoethyl)-2-(naphthalen-1-yloxy)acetamide oxalate (6b) was found to have potency, onset and duration of action comparable to that of lidocaine (2) (lidocaine hydrochloride, CAS 6108-05-0). Procaine (1) (procaine hydrochloride, CAS 51-05-8) was also used for comparison. Dissociation constants (pKa) of compounds 5a and 5b (2-substituted-N-(2-diethylaminoethyl)acetamide) have been determined to be 8.9 and 8.6, respectively.

Acetamides↗

PubMed1991

[Distribution of bromo[methylene-3H]acetamide in Oncomelania snails, carps, and mice].

Bromoacetamide show a high molluscicidal effect, low toxicity to fish and good solubility in water. It is a promising molluscicide. The present paper reported the distribution of bromo[methylene-3H]acetamide in Oncomelania snails, carps, and mice. Radioactivity in animals was measured by liquid scintillation counting. In Oncomelania snails the radioactivity gradually increased with exposure time and drug concentration. The highest level was found in the head-foot, reaching 12.5 x 10(3) dpm.mg-1 after exposure to the drug for 24 h, whereas the levels in liver and other tissue were 3.0 x 10(3) and 3.8 x 10(3) dpm.mg-1 respectively. Carps absorbed bromo[methylene-3H] acetamide similarly as in Oncomelania snails, but the levels in tissues were less than those in Oncomelania snails. Bromo[methylene-3H]acetamide 0.5 ml (1.4 mumol.L-1) was given ig to mice. Blood samples of 3 mice were collected at 0.5, 1, 3, 6, 12, 24 and 96 h after ig. The peak levels was found within 12 h and then declined gradually.

Acetamides↗

PubMed1994

Effects of acetamide on experimentally-induced Palicourea marcgravii (St Hill) poisoning in rats.

High indices of mortality in cattle have been reported in Brazil as a consequence of Palicourea marcgravii (Pm) acute intoxications. It has been established that Pm leaves contain monofluoroacetic acid (MFA), the active toxic principle of the plant. Rational therapy for MFA poisoning involves the use of a substance that might prevent fluorocitric acid formation. The present work was undertaken to verify if acetamide, a MFA antidote and an acetate donor, protects rats against both Pm and MFA intoxications. It was verified that acetamide protected rats from both convulsions and death. Future experiments should be carried out on cattle to examine the efficiency of acetamide, and particularly under field conditions.

Acetamides↗

PubMed2004

Bimolecular homolytic substitution (S(H)2) reactions with hydrogen atoms. time-resolved electron spin resonance detection in the pulse radiolysis of alpha-(methylthio)acetamide.

Pulse radiolysis of aqueous solutions of alpha-(methylthio)acetamide produced unexpectedly large quantities of acetamide radicals that were identified by time-resolved electron spin resonance (TRESR) spectroscopy. The pH dependence of the TRESR-measured radical yields, results from selective scavenging reactions, and density functional theory predictions of the reaction thermochemistry prove that bimolecular homolytic substitution, S(H)2, of the acetamide radical fragment by a H atom is the most likely formation pathway.

Journal Article↗

PubMed1992

Urea and 2-imidazolidone derivatives of the muscarinic agents oxotremorine and N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide.

Some urea and 2-imidazolidone analogues of the muscarinic agents oxotremorine (1) and N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide [10; BM-5] have been synthesized and assayed for muscarinic and antimuscarinic activity on the isolated guinea pig ileum. The new compounds (15-24) were found to be muscarinic agonists, partial agonists, or antagonists. The compounds were also tested for in vitro receptor binding to homogenates of the rat cerebral cortex using the muscarinic antagonist [3H]-3-quinuclidinyl benzilate ([3H]QNB) as the ligand. They were found to be less potent than 1 in this assay. On the guinea pig ileum, the N-3-methyl substituted imidazolidone analogue 20 was the most potent agonist of the new compounds studied; 20 was 5-fold more potent in inducing contractions of the ileum and had 4-fold higher affinity for ileal muscarinic receptors than the 3-methyl substituted 2-pyrrolidone 6. However, the N-3-unsubstituted urea and imidazolidone derivatives 15 and 19 were several-fold less potent than the parent acetamide N-methyl-N-(4-pyrrolidino-2-butynyl)acetamide [9; UH-5] and 1, respectively. The urea analogue (16) of the partial muscarinic agonist 10 was devoid of intrinsic activity and displayed 3-fold lower affinity than 10 for ileal muscarinic receptors.

Animals↗

PubMed1989

Highly selective kappa-opioid analgesics. 2. Synthesis and structure-activity relationships of novel N-[(2-aminocyclohexyl)aryl]acetamide derivatives.

This paper describes the chemical synthesis and the development of structure-activity relationships (SAR) for the kappa opioid receptor affinity and mu/kappa opioid receptor selectivity of novel N-[(2-aminocyclohexyl)aryl]acetamide derivatives. The SAR of this series are investigated by consideration of structural modifications made to the aromatic moiety, the amide linkage, and cyclohexane and the pyrrolidine ring substituents of the prototype kappa selective agonist, PD117302 (trans-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzo[b]thiophene-4- acetamide) (1). The kappa and mu opioid receptor binding affinities of 23 novel compounds are reported. It is observed that optimal mu/kappa receptor selectivity is obtained with a benzo[b]thiophene aromatic system attached via the C-4 position, which is discussed in terms of steric and electronic parameters. The amide linkage has been replaced with the reversed amide, an ester, an aminomethylene, a thioamide, and a secondary amide. The best of these isosteres is the N-methyl amide. Substitution of the pyrrolidine ring of PD117302 in the 3-position with a hydroxymethylene group increases the mu/kappa selectivity compared to the unsubstituted compound, e.g. compound 14, trans-(+/-)-N-methyl-N-[2-[3-(hydroxymethyl)-1-pyrrolidinyl] cyclohexyl]-4-benzo[b]furanacetamide monohydrochloride, mu/kappa receptor selectivity = 244. The cis fused, 4,5 dimethyl ether substituted cyclohexane analogue trans-(+/-)-N-methyl-N-[4,5-dimethoxy-2-(1-pyrrolidinyl) cyclohexyl]-benzo[b]thiophene-4-acetamide monohydrochloride (32) has high in vitro kappa opioid receptor affinity (Ki = 16 nM) and equipotent analgesic activity to morphine after iv administration in rats.

Analgesics, Opioid↗

PubMed2001

Pharmacokinetics of levetiracetam and its enantiomer (R)-alpha-ethyl-2-oxo-pyrrolidine acetamide in dogs.

PURPOSE: The new antiepileptic drug, levetiracetam (LEV, ucb LO59), is a chiral molecule with one asymmetric carbon atom whose anticonvulsant activity is highly enantioselective. The purpose of this study was to evaluate and compare the pharmacokinetics (PK) of LEV [(S)-alpha-ethyl-2-oxo-pyrrolidine acetamide] and its enantiomer (R)-alpha-ethyl-2-oxo-pyrrolidine acetamide (REV) after i.v. administration to dogs. This is the first time that the pharmacokinetics of both enantiomers has been evaluated. METHODS: Optically pure LEV and REV were synthesized, and 20 mg/kg of individual enantiomers was administered intravenously to six dogs. Plasma and urine samples were collected until 24 h, and the concentrations of LEV and REV were determined by an enantioselective assay. The levels of 2-pyrrolidone-N-butyric acid, an acid metabolite of LEV and REV, were determined by high-performance liquid chromatography (HPLC). The data were used for PK analysis of LEV and REV. RESULTS: LEV and REV had similar mean +/- SD values for clearance; 1.5 +/- 0.3 ml/min/kg and volume of distribution; 0.5 +/- 0.1 L/kg. The half-life (t1/2) and mean residence time (MRT) of REV (t1/2, 4.3 +/- 0.8 h, and MRT, 6.0 +/- 1.1 h) were, however, significantly longer than those of LEV (t1/2, 3.6 +/- 0.8 h, and MRT, 5.0 +/- 1.2 h). The renal clearance and fraction excreted unchanged for LEV and REV were significantly different. CONCLUSIONS: In addition to the enantioselective pharmacodynamics, alpha-ethyl-2-oxo-pyrrolidine acetamide has enantioselective PK. The enantioselectivity was observed in renal clearance. Because REV has more favorable PK in dogs than LEV, the higher antiepileptic potency of LEV is more likely due to intrinsic pharmacodynamic activity rather than to enantioselective PK.

Animals↗

PubMed1985

The effects of colchicine analogues on the reaction of tubulin with iodo[14C]acetamide and N,N'-ethylenebis(iodoacetamide).

We have previously found (Ludueña, R. F., and Roach, M. C. (1981b) Biochemistry 20, 4444-4450) that colchicine and podophyllotoxin inhibit the alkylation of tubulin by iodo[14C]acetamide and the formation of an intrachain cross-link in the beta-tubulin subunit by N,N'-ethylenebis(iodoacetamide) (EBI). It was not clear whether these effects were due to conformational changes in tubulin induced by drugs or to direct steric blockage of the sulfhydryl groups involved. In an effort to characterize further these phenomena, we have examined the effects of single-ring and bicyclic analogues of colchicine on the reaction of tubulin with iodo[14C]acetamide and EBI. We have found that neither the A-ring analogues, 3,4,5-trimethoxybenzyl alcohol, 3,4,5-trimethoxybenzaldehyde, 2,3,4-trimethoxybenzaldehyde, and benzaldehyde, nor the C-ring analogues, tropolone and tropolone methyl ether, inhibited alkylation. In contrast, colchicine, podophyllotoxin, and nocodazole and the bicyclic analogues, 5-(2',3',4'-trimethoxyphenyl)-2-methoxytropone and combretastatin, inhibited tubulin alkylation. Since the presence of a bond joining the A and C rings seems to be the determining factor in the suppression of alkylation, it is likely that inhibition by colchicine of the reaction with iodo[14C] acetamide is due largely to a conformational change induced by colchicine. A different pattern was obtained when the effects on cross-link formation by EBI were examined. Here, all the A-ring analogues, the bicyclic analogues, and colchicine, podophyllotoxin, and nocodazole all inhibited formation of the cross-link, whereas the C-ring analogue tropolone methyl ether did not inhibit cross-link formation. Since compounds whose effect on alkylation is markedly different have the same effect on cross-link formation, it is possible that this effect is a steric one and that perhaps the A-ring of colchicine binds to tubulin very close to one of the sulfhydryls involved in the intrachain cross-link formed by EBI in beta-tubulin.

Alkylation↗

PubMed1994

Synthesis of N-heteryl-beta-[(2-alkoxyethyl)oxy]/beta-[[2-(N,N- dialkylamino)ethyl]oxy]acetamides as possible H1-antihistaminics.

The synthesis of beta-[2-(alkoxyethyl)oxy]- and beta-[[2-(N,N-dialkylamino)ethyl]oxy]acetamides containing an N-heteryl moiety is reported. Three heteryl systems, 2-phenyl/methyl-3,4-dihydro-4-oxoquinazolin-3- yl, 5-aryl-1,3,4-oxadiazol-2-yl, and 5-alkyl-1,3,4-thiadiazol-2-yl, were employed. Appropriate heterylamines were first converted into their respective chloroacetamides and then reacted with 2-alkoxyethanols/2-(N,N-dialkylamino)ethanols in dry acetone in the presence of anhydrous potassium carbonate to obtain the title compounds. Ten such new acetamides from each series were synthesized and characterized. Their in vitro antihistaminic activity was determined using the isolated guinea pig ileum method. The IC50 values of the compounds indicated correlations with their structural and electronic features.

Acetamides↗

PubMed1994

Arg-188 and Trp-144 are implicated in the binding of urea and acetamide to the active site of the amidase from Pseudomonas aeruginosa.

Urea is a time-dependent active-site-directed inhibitor of Pseudomonas aeruginosa amidase. We found that 20 mM hydroxylamine caused bound urea to be released from the inactive urea:amidase complex with the restoration of enzyme activity. Bound urea restricts the titrability of the enzyme's -SH groups to 6 per hexameric molecule and protects it against thermal denaturation suggesting that urea binding provokes a conformational change in the enzyme. Mutations in the P. aeruginosa amidase gene that reduce the binding affinity of the enzyme for both urea and the substrate acetamide have been identified by direct sequencing of PCR-amplified mutant genes and confirmed by sequencing cloned PCR-amplified genes. The mutations were in two regions of the enzyme substituting either Arg-188 (or Gln-190, in one case) or Trp-144; one amidase that bound neither urea nor acetamide was doubly mutant with an amino-acid change at both sites.

Acetamides↗