New amides of 5-(4-chlorobenzoyl)aminoorotic acid: their synthesis and biological activity

The synthesis and in-vitro biological evaluation of the amide series 4 of 5-(4-chlorobenzoyl)aminoorotic acid 2 are presented. The biological properties of a few 5-(4-chlorobenzoyl)amino-2,6-dihydroxy-N-substituted-4-pyrimidinecarboxamide derivatives 4 tested here were compared with those of the isosteric isothiazole derivative MR-2/94 (5-(4-chlorobenzoyl)amino-N-(4-chlorophenyl)-3-methyl-4-isothiazolecarboxamide), which possesses a strong immunosuppressive and anti-inflammatory activity [1, 2], It must be suggested that replacement of the isothiazole by a pyrimidine core ring system resulted in considerable lowering of the anti-inflammatory and immunotropic actions of the obtained amides. Physicochemical properties of 2-(4-chlorophenyl)-6,8-dihydroxy-4H-pyrimido[5,4-d]-1,3-oxazin-4-on 3 are also briefly described.     

Synthesis, physicochemical and anticonvulsant properties of new N-4-arylpiperazin-1-yl amides of (2-aza-1,3-dioxospiro[4.4]non-2-yl)- and [4.5]dec-2-yl)-propionic acid

In continuation of the search of new anticonvulsants, a series of N-4-arylpiperazin-1-yl 2-aza-1,3-dioxospiro[4.4]non-2-yl- (5-8) and [4.5]dec-2-yl- (9-15) propionamides, structurally related to the previously described N-4-arylpiperazin-1-yl amides of 2-aza-1,3-dioxospiro[4.5]dec-2-yl-acetic acid, were synthesized. The designed compounds 5-15 were prepared by condensation of the formerly obtained (2-aza-1,3-dioxospiro[4.5]dec-2-yl)- (3) and (2-aza-1,3-dioxo[4.4]non-2-yl)-(4) propionic acids with the appropriately substituted 4-arylpiperazines, in the presence of the N,N-carbonyldiimidazole (CDIM) reagent. All the compounds were tested for their anticonvulsant activity in the maximum electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. Several compounds 7-10, 13 and 14 revealed protection in the MES screening.     

Synthesis of a series of 3-cyanopropionamides and 4-imino-gamma-butyrolactams and evaluation of their function as modulators of multidrug resistance

The synthesis of the 3-cyanopropionamides 3a and 3b, of the 2,2-dimethyl-3-cyanopropionamides 4a-4c and of the 4-imino-gamma-butyrolactams 5a and 5b (cyclic functional isomers of 3-cyanopropionamides) is described. The amides 3a and 3b were obtained by aminolysis of the corresponding acid chlorides, which are accessible via hydrolysis of the ethyl esters to the acids. This methodology was not used for the synthesis of the amides 4a-4c owing to steric hindrance to hydrolysis in the corresponding ethyl esters. These nonreactive esters, accessible by alkylation of 1-cyano carbanions with ethyl bromodimethylacetate, could be directly converted into the amides 4a-4c by aminolysis with the lithium amide of 3,4-dimethoxy-N-methylphenethylamine. Instead of open-chain amides, the lactams 5a and 5b are obtained when the lithium amide of 3,4-dimethoxyphenethylamine (i.e., of a primary rather than secondary amine) is used for the aminolysis. The synthesized compounds were tested for their ability to decrease the resistance to vincristine in a multidrug-resistant subline of murine leukemic lymphoblasts that are 300-fold resistant to the antiproliferative drug. The amides 4a and 4c, and lactam 5a, all of which have a highly branched carbon backbone, were active. Lactam 5a reduced the vincristine resistance by 90% at a 2-microM concentration.     

Synthesis and 5-HT3 receptor affinity of new quinolinecarboxylic acid derivatives

A series of quinolinecarboxylic acid amides and an ester with a quinuclidine moiety were synthesized and their in vitro affinities at 5-HT3, 5-HT4, and D2 receptors evaluated by radioligand binding assays. Highest affinity at 5-HT3 receptor corresponded to derivative 5 with Ki = 9.9 nM and with selectivity over 5-HT4 and D2 receptors. Compounds displayed moderate 5-HT3 antagonist activity (ED50 = 10.5-21.5 microg/kg i.v.). The obtained data suggest that the 5-HT3 receptor sites can accommodate the acyl group of the 2-quinoline derivatives. The results indicate the existence of an optimal distance between the lone electron pair of the quinoline nitrogen atom and the azabicyclic nitrogen atom, and a no-pharmacophoric pocket in the 5-HT3 receptor which would hold the fragment at the position 4 of the quinoline ring.     

Synthesis of amides of 2,4-dioxothiazolidin-5-yl acetic acid with 1,2,4-triazole substituents

In the reaction of (2,4-dioxothiazolidin-5-yl)acetyl chloride with 1,2,4-triazole, 4-phenyl-1,2,4-triazolin-5-one and 4-phenyl-1,2,4-triazolin-5-thione, the new corresponding amides (2-4) were obtained. For compounds 2 and 4 effects on central nervous system (CNS) of mice were studied.     

Immunomodulating action and structure-activity relationships of substituted phenylamides of 5-amino-3-methylisoxazole-4-carboxylic acid.

A series of 5-amino-3-methylisoxazole-4-carboxylic acid amides has been prepared by condensation of 5-amino-3-methylisoxazole-4-carboxylic acid with ethyl chloroformate. The resulting mixed anhydride undergoes condensation with appropriate phenylamides to form the corresponding amides 6-16. The compounds obtained were evaluated for their immunological activities in cultures of human peripheral blood mononuclear cells (PMBC). We found that the activities of the compounds in the proliferation test and in the lipopolysaccharide (LPS)-induced cytokine production in PBMC cultures were differential. The stimulatory or inhibitory effects depended strongly on the origin and location of substituents in the phenyl ring which is described in the discussion and was supported by QSAR studies.     

Synthesis of 2-hydrazolyl-4-thiazolidinones based on multicomponent reactions and biological evaluation against Trypanosoma Cruzi

A series of 18 novel 2-hydrazolyl-4-thiazolidinones-5-carboxylic acids, amides and 5,6-α,β-unsaturated esters were synthesized, and their in vitro activity on cruzipain and T. cruzi epimastigotes was determined. Some agents show activity at 37 μm concentration in the enzyme assay. Computational tools and docking were used to correlate the biological response with the physicochemical parameters of the compounds and their cruzipain inhibitory effects.     

2-Amino-3-cyano-dihydroindol-5-ones. 3. The chemical reactivity of a new class of compounds]

The chemical reactivity of cytotoxic 5-indolone derivatives is examined in order to get ideas about their behaviour in biological systems. Dienone-phenol-rearrangement preserving the indole ring system could not be achieved, aromatization of 1b gives the phenol derivative 3 alpha. In diluted NaOH ester hydrolysis occurs (1a,b----4a,b). Hydrolysis in conc. H2SO4 yields the amides 5a,b,d. In ethanolic HCl the ammonium salts 6a,b,d are formed. Acylation of 1a to 8 reveals the endocyclic N-atom as the nucleophilic center. Benzaldehyde being a strong electrophile adds to 1b in position 4. Weaker electrophiles such as dimethyl acetylenedicarboxylate (ADC) only react with the amides 5b,d to give 11 and 12. Nucleophiles (water, ethanol, n-propylamine) add to the delta 6-double bond yielding 14-16.     

Synthesis and antimicrobial activity of benzofuran-carboxamide derivatives

The reaction of the sodium salts of 4-methoxy and 4,7-dimethoxy 6-hydroxy-benzofuran-5-carboxylic acid with ethyl chloroformate yields the corresponding dicarbethoxy derivatives. The N-substituted amides were obtained by treating the latter compounds with amines. The corresponding hydrazides were synthesized by the reaction of hydrazine hydrate on the dicarbethoxy derivatives which spontaneously cyclized to 5-substituted-2,3-dihydro-1,3,4-oxadiazol-2-one. Also the reaction with phenyl hydrazine has been studied. The dicarbethoxy derivatives and N-substituted amides were tested against Gram positive and Gram negative bacteriain vitro. Most of the compounds possess moderate or slight activity against Gram positive bacteria.     

The Novel Ketoprofen Amides – Synthesis and Biological Evaluation as Antioxidants,Lipoxygenase Inhibitors and Cytostatic Agents

The novel amides of ketoprofen and its reduced derivatives (5a–f, 4a–n, 6a–g) with aromatic and cycloalkyl amines or hydroxylamines were prepared and screened for their reducing and cytostatic activity as well as for their ability to inhibit soybean lipoxygenase and lipid peroxidation. 1,1-Diphenyl-picrylhydrazyl test for reducing ability revealed that ketoprofen amides were more potent antioxidants than the amides of the reduced ketoprofen derivatives. The most active compound was benzhydryl ketoprofen amide 5f. Lipoxygenase inhibition of the tested compounds varied from strong to very weak. The most potent compound was benzhydryl derivative 6f (IC₅₀ = 20.5 μm ). Aromatic and cycloalkyl amides 4 and 5 were more potent lipoxygenase inhibitors than derivatives with carboxylic group. Aromatic amides of series 4 and 5 showed excellent lipid peroxidation inhibition (92.2–99.9%). On the other hand, the most pronounced cytostatic activity was exerted by O-benzyl derivative 4i, although in general all tested reduced and non-reduced lipophilic derivatives showed similar activity.     

Nonpeptide renin inhibitors employing a novel 3-aza(or oxa)-2,4-dialkyl glutaric acid moiety as a P2/P3 amide bond replacement.

A new series of renin inhibitors has been developed. The inhibitors feature a novel replacement for the P2/P3 dipeptide moiety normally associated with renin inhibitors. The dipeptide replacement was a (2S,4S)-3-aza(or oxa)-2,4-dialkylglutaric acid amide. Extensive structure-activity relationship studies determined that optimum potency was achieved when inhibitors employed a benzyl and butyl group at the C(4) and C(2) carbon position, respectively. In addition, maximum in vitro potency was obtained when the N-terminus was functionalized by incorporating a 4-(1,3-dioxabutyl)piperidine amide. SAR data suggested that the 1,3-dioxabutyl group (methoxymethyl ether) interacted by hydrogen bonding to groups in the S4 domain of renin. This hypothesis was strengthened when a 4-butylpiperidine amide was substituted and inhibitor potency decreased dramatically. Inhibitors employing this novel dipeptide mimic were prepared by coupling the glutaric acid amides with either the transition-state mimic (2S,3R,4S)-2-amino-1-cyclohexyl-3,4-dihydroxy-6- methylheptane (18) or the hydroxyethylene dipeptide isostere. The glutaric acid amides were prepared by two general procedures. The first procedure involved the reductive amination of alpha-amino acid esters with alpha-keto esters. The second procedure involved the displacement reaction of alpha-bromo esters or acids with alpha-amino acid amides.     

Synthesis, absolute configuration, and antibacterial activity of 6,7-dihydro-5,8-dimethyl-9-fluoro-1-oxo-1H,5H- benzo[ij]quinolizine-2-carboxylic acid

The tricyclic quinolone antibacterial agent 6,7-dihydro-5,8-dimethyl-9-fluoro-1-oxo-1H,5H-benzo[ij]quinolizine -2-carboxylic acid has an asymmetric center at position 5 of the molecule. The R and S isomers of the compound have been prepared from the corresponding (R)- and (S)-2,5-dimethyl-6-fluoro-1,2,3,4-tetrahydroquinolines, which were separated via their diastereomeric amides of N-tosyl-(S)-proline. The absolute configuration was established by X-ray analysis of one of the diastereomeric amides. The 5-desmethyl analogue was prepared for antibacterial comparison with the isomers and the racemic mixture. It has now been established that the S isomer is much more active than the R isomer. The 5-desmethyl analogue was found to be more active than the R isomer but not as active as the S isomer or the racemic mixture. The importance of stereochemistry at position 5 in this system has been established.     

Synthesis of isothiazole derivatives with potential biological activity.

The synthesis of acyl and ureido derivatives of substituted amides of 3-methyl-5-aminoisothiazole-4-carboxylic acid is presented. The structures of the compounds obtained were established on the basis of IR, 1H NMR and elemental analysis. The influence on the circulatory system of the derivatives was investigated. All structures of the compounds obtained were fully confirmed by IR and 1H NMR as well as by elemental analysis (Table).     

Chloroquine analogues from benzofuro- and benzothieno[3,2-b]-4-pyridone-2-carboxylic acid esters

The amides 7 were synthesized from the annulated methyl 4-pyridone-2-carboxylates 4 via the carboxylic acids 5 and their acid chlorides by reacting with the novaldiamine base 6. The alcohol 8b, obtained from DIBAH reduction of the ester 4b, was transformed to the chloromethyl derivative 9 which reacted with 6 and 18-crown-6 leading to the 2-novaldiaminomethyl-4-pyridone 10. Compound 10 was obtained with higher yield from DIBAH reduction of the amide 7b. The substances 7 and 10 were inactive when tested against the chloroquine resistant Plasmodium falciparum strain Dd2.     

Design and synthesis of some substituted 1H-pyrazolyl-oxazolidines or 1H-pyrazolyl-thiazolidines as anti-inflammatory-antimicrobial agents

Four series of 1 H-pyrazole derivatives have been synthesized. The first series was synthesized starting with the reaction of 3-(5-bromo-2-thienyl)-1-phenyl-1 H-pyrazole-4-carboxaldehyde 1 with L-serine, L-cysteine, or L-penicillamine, followed by N-protection using (Boc)(2)O to provide compounds 2. The latter compounds could be N-deprotected by 4N HCl/dioxane to afford the second series 3 or reacted with NH(4)OH in the presence of DCC/HOBt to give the corresponding amides 4 followed by N-deprotection giving rise to compounds 5. The newly synthesized compounds were evaluated for their anti-inflammatory-antimicrobial activities. In addition, the ulcerogenic and acute toxicity profiles were determined. Compound 5b (2RS, 4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-5-methylthiazolidine-4-carboxamide, proved to be the most active anti-inflammatory-antimicrobial agent in the present study with a good safety margin and no ulcerogenic effect.     

Application of n.c.a. 4‐[18F]fluorophenol in diaryl ether syntheses of 2‐(4‐[18F]fluorophenoxy)‐benzylamines

The availability of no‐carrier‐added (n.c.a.) 4‐[¹⁸F]fluorophenol offers the possibility of introducing the 4‐[¹⁸F]fluorophenoxy moiety into potential radiopharmaceuticals. Besides alkyl–aryl ether synthesis using n.c.a. 4‐[¹⁸F]fluorophenol the diaryl ether coupling is an attractive synthetic method to enlarge the spectrum of interesting labelling procedures. As examples the syntheses of n.c.a. 2‐(4‐[¹⁸F]fluorophenoxy)‐N,N‐dimethylbenzylamine and n.c.a. 2‐(4‐[¹⁸F]fluorophenoxy)‐N‐methylbenzylamine were realized by an Ullmann ether synthesis of corresponding 2‐bromobenzoic acid amides using tetrakis(acetonitrile)copper(I) hexafluorophosphate as catalyst and a subsequent reduction of the amides formed. The radiochemical yield of the coupling varied between 5 and 65% based on labelled 4‐[¹⁸F]fluorophenol. Both compounds are structural analogues of recently published radiotracers for imaging the serotonin reuptake transporter sites (SERT). However, in vitro binding assays of both molecules showed only a low affinity towards monoamine transporters. Copyright © 2004 John Wiley & Sons, Ltd.     

An alternative way of the synthesis of 1-substituted 9-methoxy-5-methyl-6H-pyrido[4,3-b]carbazole derivatives

A keystone of this work was a modification of synthesis of the title compounds, which were used as substrates for the preparation of amides 5, 9-methoxyolivacine (4a) and ethyl 9-methoxy-5-methyl-6H-pyrido[4,3-b]carbazole-1-carboxylate (4b) were obtained in good overall yields (4a--72%, and 4b--31%) on alternative ways of the synthesis. The pilot results of the cytostatic activity of iminium salts 12a (IC50 = 8 microM) and 12b (IC50 = 2 microM) were determined on L1210 mouse leukaemia cells.     

Synthesis, physicochemical and anticonvulsant properties of some n-substituted amides of 3-spirocycloalkylpyrrolidine-2,5-dione

The synthesis and physicochemical properties of new derivatives of N-benzyl and N-phenyl amides of 2-(3-spirocyclohexanepyrrolidine-2,5-dione) acetic acid. 4-(3-spirocyclohexanepyrrolidine-2,5-dione) benzoic acid and 4-(3-spirocyclopentanepyrrolidine-2,5-dione) benzoic acid are described. N-substituted amides were prepared by condensing the obtained acids with the corresponding phenyl- or benzylamine derivatives in DMF, in the presence of the N,N-carbonyldiimidazol (CDIM) reagent at room temperature. The compounds were evaluated for anticonvulsant activity. The portion coefficients were calculated using the Prolog P module of the Pallas system. The structure of the new amides was confirmed by elemental and spectral analyses.     

Convergent synthesis of two 14C‐labeled β3‐adrenergic receptor agonists

The synthesis of β₃‐adrenergic receptor agonists A and B with radiolabeled amide fragment, required for drug disposition studies, was accomplished based on initial formation of 2‐(4‐(2‐amino‐2‐methylpropyl)phenoxy)‐5‐[¹⁴C]‐cyanopyridine by the reaction of 2‐bromo‐5‐iodopyridine with para‐substituted phenol, and following cyanation of aromatic iodide with potassium cyanide‐[¹⁴C]. After the coupling of the resulted amine with glycidyl derivatives of 4‐hydroxyindole and 4‐hydroxycarbazole, the corresponding nitriles were hydrolyzed with basic hydrogen peroxide to obtain target amides A and B . Copyright © 2006 John Wiley & Sons, Ltd.     

Peptides containing dialkylglycines

A short route for the preparation of 2-trifluoromethyl-4,4-dialkyloxazolin-5-ones (Tdo's), useful reagents for the addition of dialkylglycine residues to the N-terminus of peptides, was examined. 2-Trifluoromethyl-oxazolin-5(4H)-one proved too unstable for a general substrate for alkylation, but 2-trifluoromethyl-4-alkyl-oxazolin-5(2H)-ones, readily available from protein amino acids, could be alkylated to Tdo's in the presence of mild base using active alkyl halides. 2-Trifluoromethyl-4,4-dibenzyl-oxazolin-5-one, prepared in this way as a stable crystalline solid, coupled well with protein amino acid esters or amides, confirming the utility of reagents of this type. Of a number of alkylations examined, only in the case of 2-trifluoromethyl-4-isobutyl-oxazolin-5(2H)-one using isobutenyl iodide was the isomeric 2-trifluoromethyl-2-isobutenyl-4-isobutyl-oxazolin-5-one observed at all; in this case, it predominated. Ammonolysis of Tdo's gave Tfa-dialkylglycine amides, N-deprotection of which using NaBH₄ unexpectedly gave 2-trifluoromethyl-4,4-dialkylimidazol-5-ones. The partition coefficients (P) of a series of N-acetyldialkylglycinamides were measured. Comparison with the values obtained for similar derivatives of the corresponding protein amino acids showed a close correlation between the increasing hydrophobicity of the second side chain of the dialkylglycine derivative and the log P values obtained.