Anticonvulsant activity of 2- and 3-aminobenzanilides

One-Pot Synthesis of Seven-Membered Heterocyclic Derivatives of Diazepines Involving Copper-Catalyzed Rearrangement Cascade Allyl-Amination

A novel and efficient method has been proposed for the synthesis of 1,4-benzodiazepine-5-ones from o-nitrobenzoic N-allylamides by using molybdenyl acetylacetonate and copper(II) trifluoromethanesulfonate as catalysts in the presence of triphenylphosphine. This synthesis process involves nitrene formation, C-H bond insertion, C═C bond rearrangement, and C-N bond formation cascade reactions via copper- and molybdenum-catalyzed mediation. The method features a wide substrate scope and a moderate to high yield (up to 90%), exhibiting the possibility for practical applications.

Synthesis and anticonvulsant activity of some ω-(1H-imidazol-1-yl)-N-phenylacetamide and propionamide derivatives

In this study, eight new omega-(1H-imidazol-1-yl)-N-phenylacetamide and propionamide derivatives having 2,6-dimethyl, 2,6-dichloro, 2-chloro-6-methyl and 2-isopropyl substitutions on N-phenyl ring were synthesized to evaluate anticonvulsant activity against maximal electroshock test. The most active compounds in the series were the derivatives bearing 2-isopropyl and 2,6-dimethyl substituents on N-phenyl ring.

Synthesis and antibacterial evaluation of certain quinolone derivatives

A number of 7-substituted quinolone derivatives were synthesized and evaluated for antibacterial and cytotoxic activities. Preliminary results indicated that most compounds tested in this study demonstrated better activity against methicillin-resistant Staphylococcus aureus than norfloxacin. Among them, 1-(4-amino-2-fluorophenyl)-6-fluoro-1,4-dihydro-7-[4-[2-(4-methoxyphenyl)-2-hydroxyiminoethyl]-1-piperazinyl]-4-oxo-3-quinolinecarboxylic acid (11d) and its ketone precursor 10d exhibited significant activities against Klebsiella pneumoniae, methicillin-resistant S. aureus, erythromycin- and ampicillin-resistant Streptococcus pneumoniae, and vancomycin-resistant Enterococcus faecalis. Due to strong cytotoxicities of 11d (a mean log GI(50) of -5.40), compound 10d, with good antibacterial activities and low cytotoxicities (a mean log GI(50) of -4.67), is a more potential drug candidate.

Synthesis and structure-activity relationships of potential anticonvulsants based on 2-piperidinecarboxylic acid and related pharmacophores

Using N-(2,6-dimethyl)phenyl-2-piperidinecarboxamide (1) and N-(alpha-methylbenzyl)-2-piperidinecarboxamide (2) as structural leads, a variety of analogues were synthesised and evaluated for anticonvulsant activity in the MES test in mice. In the N-benzyl series, introduction of 3-Cl, 4-Cl, 3,4-Cl2, or 3-CF3 groups on the aromatic ring led to an increase in MES activity. Replacement of the alpha-methyl group by either i-Pr or benzyl groups enhanced MES activity with no increase in neurotoxicity. Substitution on the piperidine ring nitrogen led to a decrease in MES activity and neurotoxicity, while reduction of the amide carbonyl led to a complete loss of activity. Movement of the carboxamide group to either the 3- or 4-positions of the piperidine ring decreased MES activity and neurotoxicity. Incorporation of the piperidine ring into a tetrahydroisoquinoline or diazahydrinone nucleus led to increased neurotoxicity. In the N-(2,6-dimethyl)phenyl series, opening of the piperidine ring between the 1- and 6-positions gave the active norleucine derivative 75 (ED50=5.8 mgkg(-1), TD50 =36.4 mgkg(-1), PI=6.3). Replacement of the piperidine ring of 1 by cycloalkane (cyclohexane, cyclopentane, and cyclobutane) resulted in compounds with decreased MES activity and neurotoxicity, whereas replacement of the piperidine ring by a 4-pyridyl group led to a retention of MES activity with a comparable PI. Simplification of the 2-piperidinecarboxamide nucleus of 1 into a glycinecarboxamide nucleus led to about a six-fold decrease in MES activity. The 2,6-dimethylanilides were the most potent compounds in the MES test in each group of compounds evaluated, and compounds 50 and 75 should be useful leads in the development of agents for the treatment of tonic-clonic and partial seizures in man.

Synthesis, antibacterial, and cytotoxic evaluation of certain 7-substituted norfloxacin derivatives

We report herein the synthesis and biological evaluation of two series of 7-substituted norfloxacin derivatives. Most compounds tested in this study demonstrated better activity against methicillin-resistant Staphylococcus aureus than norfloxacin. Preliminary in vitro evaluation indicated that the 7-[4-(2-hydroxyiminoethyl)piperazin-1-yl] derivatives 3b-e possess distinct cytotoxicity profiles as compared with their alpha-methylene-gamma-butyrolactone counterparts, 4b,e: i.e., excellent activities against the renal cancer subpanel. Among them, 1-ethyl-6-fluoro-7-¿4-[2-(4-chlorophenyl)-2-hydroxyiminoethyl]-1-p ipe razinyl¿-4-oxo-1,4-dihydro-3-quinolinecarboxylic acid (3d) demonstrated the most significant activities against renal cancer cell lines, with log GI(50) values of -6.40 against CAK-1, -6.14 against RXF 393, and -7.54 against UO-31, compared with a mean log GI(50) value of -5.03.

Anticonvulsant profile of 4-amino-(2-methyl-4-aminophenyl)benzamide in mice and rats

An original ameltolide analogue 4-amino-(2-methyl-4-aminophenyl)benzamide, in which a second amino group has been introduced, was synthesized and evaluated for anticonvulsant activity. After intraperitoneal administration to mice, 4-amino-(2-methyl-4-aminophenyl)benzamide was found active in the maximal electroshock seizure test and against the tonic seizures elicited either by bicuculline or 3-mercaptopropionic acid. 4-amino-(2-methyl-4-aminophenyl)benzamide (4A-2M4A-PB) gave anti maximal electroshock seizures ED50 of 63 micromol/kg (15.4 mg/kg) and a TD50 of 676 micromol/kg (163 mg/kg), yielding a PI of 10.7; the potency is similar to that of the 4-amino-(2-methyl-3-aminophenyl)phthalimide (4A-2M3A-PP), superior to that of 4-amino-(2,6-dimethylphenyl)phthalimide (4A-2,6-DMPP), close to that of phenytoin and carbamazepine and inferior to that of ameltolide. 4A-2M4A-PB with an ED50 of 41[28-60] micromol/kg (9.9 mg/kg) is as active after oral administration to rats as carbamazepine, more active than ameltolide, 4-A-2M3A-PP and phenytoin and slightly less active than the 4A-2,6-DMPP. The introduction of a second amino group on the substituted phenyl ring does not affect drastically the anticonvulsant potency after intraperitoneal administration to mice; moreover, it seems to enhance the activity after oral administration. 4A-2M4A-PB is a good candidate both for further pharmacokinetic studies and for the study of the precise mechanism of action.

Anticonvulsant and neurotoxicological properties of 4-amino-N-(2-ethylphenyl)benzamide, a potent ameltolide analogue

A well documented study on the anticonvulsant properties of 4-amino-N-(2-ethylphenyl)benzamide (4-AEPB) is here provided. Initial screening in mice dosed intraperitoneally and rats dosed orally indicated that 4-AEPB is active against maximal electroshock-induced seizures (MES), but does not protect animals against subcutaneous pentylenetetrazole (sc Ptz)-induced seizures. Quantitative evaluation of anti-MES activity and neurotoxicity of 4-AEPB given intraperitoneally to mice provided ED50 and TD50 values amounting to 28.6 and 96.3 mumol/kg respectively, resulting in a protective index (PI = TD50/ED50) equal to 3.36. Further quantitative evaluation in rats dosed orally indicated that the respective ED50 and TD50 values for 4-AEPB were 29.8 and more than 1,530 mumol/kg, resulting in a very high PI value of over 51. Comparison anticonvulsant properties and neurotoxicity of 4-AEPB with those previously reported in the literature for two 4-aminobenzamide derivatives, 4-amino-N-(2,6-dimethylphenyl)benzamide (or ameltolide, an antiepileptic drug prototype developed by Eli Lilly), and phenytoin, underlines the value of 4-AEPB for future pharmacological development. In this perspective, an additional favorable element is represented by the ability of 4-AEPB to increase the seizure threshold in the intravenous Ptz seizure threshold test in mice dosed intraperitoneally. Molecular modeling studies show that the translocation of one carbon unit in the isomerization of the 2,6-dimethylphenyl moiety of ameltolide to the 2-ethylphenyl counterpart succeeds in maintaining the conformational low energy presentation adopted by ameltolide, providing clues as to why the 4-AEPB here described is an anticonvulsant agent derived from the 4-aminobenzamide pharmacophore platform as potent as ameltolide.

Anticonvulsant activity of some 4-amino-N-phenylphthalimides and N-(3-amino-2-methylphenyl)phthalimides

A series of fifteen N-phenylphthalimides including 12 4-amino-N-phenylphthalimides and three N-(3-amino-2-methylphenyl)phthalimides was prepared and evaluated for anticonvulsant properties. The compounds were tested against seizures induced by electroshock (MES) and pentylenetetrazol (scPTZ) in mice dosed intraperitoneally. Their neurologic toxicity was assessed using the rotorod assay procedure. The most potent 4-amino-N-phenylphthalimides against MES were those possessing small lipophilic groups in either 2 or 2 and 6 positions of the N-phenyl ring. They also exhibited some activity against scPTZ and were the most toxic of the series. By contrast, no activity against scPTZ or neurotoxicity could be observed up to 300 mg/kg for members of the N-(3-amino-2- methylphenyl)phthalimide series. In this series, the order of anti-MES activity appears to correspond to the phthalimide ring substitution pattern of 4-amino > H > 4-methyl. Quantitation of anticonvulsant properties and toxicity of 4-amino-N-(2,6-dimethylphenyl)phthalimide (ADD 213063) previously initiated in rats has been, here, extended to mice dosed intraperitoneally but also orally. The confrontation of the two modes of administration in mice suggests that ADD 213063 presents with a good bioavailability.

Comparative anticonvulsant activity of 4-chlorobenzenesulfonamide and prototype antiepileptic drugs in rodents

The anticonvulsant and toxic properties of 4-chlorobenzenesulfonamide (ADD 55051) were compared with phenytoin (PHT), phenobarbital (PB), ethosuximide (ESM), and valproate (VPA). These compounds were evaluated in mice and rats using well-standardized anti-convulsant test procedures. The results indicate that ADD 55051 is a very effective anticonvulsant in the maximal electroshock seizure (MES) model in mice after either intraperitoneal (i.p.) or oral administration and in rats after oral administration. In mice treated i.p. or orally, ADD 55051 was also effective in preventing seizures induced by pentylenetetrazol (PTZ). The toxicity of ADD 55051 after oral administration was quite low, yielding high TD50 values in both mice and rats and producing a very high protective index (PI = TD50/ED50) in both species as compared with the prototype antiepileptic drugs (AEDs).

Anticonvulsant activity of some 4-methoxy- and 4-chlorobenzanilides

A series of mono-, di-, and trimethylated derivatives of 4-chloro- and 4-methoxybenzanilide was synthesized and evaluated for anticonvulsant activity. This series was prepared in the course of studies designed to examine the relationship between anticonvulsant effects and benzamide structure. The compounds were tested in mice against seizures induced by maximal electroshock (MES) and pentylenetetrazole (scMet), as well as with the rotorod assay for neurologic deficit. In mice dosed intraperitoneally, 4-methoxy-2, 6-dimethylbenzanilide (4) showed a median anticonvulsant potency (ED50) of 18.58 mg/kg in the MES test and a median toxicity (TD50) of 133.72 mg/kg in the rotorod toxicity assay, yielding a protective index (PI = TD50/ED50) of 7.2. In mice dosed orally with 4, the anti-MES ED50 was 27.40 mg/kg and the TD50 dose was determined to be 342.58 mg/kg, resulting in a protective index of 12.5.

Comparative anticonvulsant activity and neurotoxicity of 4-amino-N-(2,6-dimethylphenyl)benzamide and prototype antiepileptic drugs in mice and rats

The anticonvulsant and toxic properties of 4-amino-N-(2,6-dimethylphenyl)benzamide, (ADD 75073), were compared with phenytoin (PHT), phenobarbital (PB), ethosuximide (ESM), and valproate (VPA). These compounds were evaluated in mice and rats using well-standardized anticonvulsant test procedures. The results indicate that ADD 75073 is a very potent anticonvulsant in the maximal electroshock seizure (MES) model. The compound was effective in nontoxic doses following intraperitoneal (i.p.) administration in mice and oral administration in both mice and rats. In mice, the i.p. administration of ADD 75073 resulted in an ED50 value of 2.6 mg/kg as compared with a value of 9.5 mg/kg for phenytoin (PHT) in the same assay. Compound ADD 75073 was ineffective in nontoxic doses against all other seizure models examined in this study, and thus has a pharmacologic profile similar to that of PHT.

Anticonvulsant activity of some 4-aminophenylacetamides

A series of 4-aminophenylacetamides was prepared and evaluated for anticonvulsant activity. These compounds were prepared during studies designed to determine the relationship between benzamide-like compounds and anticonvulsant effects. Unlike benzamides, these phenylacetamides have a methylene group between the aromatic ring and the amide carbonyl. Consequently, formal conjugation is lost, and the number of conformational degrees of freedom has increased. The compounds were tested in mice against seizures induced by electroshock and pentylenetetrazol, and in the rotorod assay for neurologic deficit. The more active and selective anticonvulsants prepared in this study were those having an additional aromatic ring as part of the substituent on the amide nitrogen. Compound 16, the 4-aminophenylacetamide derived from 2,6-dimethylaniline, was the most potent compound observed (ED50 = 50.50 mg/kg against electroshock-induced convulsions and ED50 = 93.20 mg/kg against pentylenetetrazol-induced convulsions).