Synthesis, characterization, and SAR studies of new (1H-indol-3-yl)alkyl-3-(1H-indol-3-yl)propanamide derivatives as possible antimicrobial and antitubercular agents

In this article, we report herein the SAR studies of a series of (1H-indol-3-yl)alkyl-3-(1H-indol-3-yl)propanamide 10(a–j), 11(a–j). The synthesized compounds were evaluated for their preliminary in vitro antibacterial, antifungal activity and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The synthesized compounds displayed interesting antimicrobial activity.     

Design,synthesis, and tripeptidyl peptidase II inhibitory activity of a novel series of (S)-2,3-dihydro-2-(4-alkyl-1H-imidazol-2-yl)-1H-indoles

Butabindide, 1, was previously reported as a potent inhibitor (IC50 = 7 nM) of the serine protease enzyme tripeptidyl peptidase II (TPPII), an endogenous protease that degrades cholecystokinin-8 (CCK-8). We found that 1 has some inherent chemical instability, yielding diketopiperazine 2 fairly readily under mimicked physiological conditions. We therefore prepared imidazoles 3, which are void of 1's inherent instability, and have found that our novel analogues maintained comparable TPPII inhibitory activity (e.g.,for 3c, IC50 = 4 nM) as 1.     

Design, synthesis, and SAR of new pyrrole-oxindole progesterone receptor modulators leading to 5-(7-fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-5-yl)-1-methyl-1H-pyrrole-2-carbonitrile (WAY-255348)

We have continued to explore the 3,3-dialkyl-5-aryloxindole series of progesterone receptor (PR) modulators looking for new agents to be used in female healthcare: contraception, fibroids, endometriosis, and certain breast cancers. Previously we reported that subtle structural changes with this and related templates produced functional switches between agonist and antagonist properties ( Fensome et al. Biorg. Med. Chem. Lett. 2002, 12, 3487; 2003, 13, 1317 ). We herein report a new functional switch within the 5-(2-oxoindolin-5-yl)-1 H-pyrrole-2-carbonitrile class of compounds. We found that the size of the 3,3-dialkyl substituent is important for controlling the functional response; thus small groups (dimethyl) afford potent PR antagonists, whereas larger groups (spirocyclohexyl) are PR agonists. The product from our optimization activities in cell-based systems and also for kinetic properties in rodents and nonhuman primates was 5-(7-fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1 H-indol-5-yl)-1-methyl-1 H-pyrrole-2-carbonitrile 27 (WAY-255348), which demonstrated potent and robust activity on PR antagonist and contraceptive end points in the rat and also in cynomolgus and rhesus monkeys including ovulation inhibition, menses induction, and reproductive tract morphology.     

Design, synthesis, and biologic evaluation of some novel N-arylpyrazole derivatives as cytotoxic agents

A novel series of N-arylpyrazole derivatives (5a–5d, 7a–7c) has been designed and synthesized via aromatic substitution reaction of N-nonsubstituted pyrazoles with 4-fluoronitrobenzene in the presence of base. The structures of these compounds were established on the basis of elemental (C, H, and N) and spectral analysis (¹H NMR, ¹³C NMR, HRMS, and FT-IR). All the compounds were tested for their cytotoxic activity in vitro against four human tumor cell lines: carcinoma (Bel-7402), nasopharyngeal carcinoma (KB), immature granulocyte leukemia (HL-60), and gastrocarcinoma (BGC-823) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results showed that most of the obtained compounds exhibited promising cytotoxicity against tested carcinoma cell lines with low IC₅₀ values. The bis-pyrazole derivative 7c, bearing alkoxy group on the 5-position of phenyl ring, was the most effective one. It is inhibition of cell growth of Bel-7402 cells was 1.5-fold higher than that found for cisplatin. And, also mono-pyrazole derivatives 5a and 5b, decorated with trifluoromethyl group on the phenyl ring, displayed better cytotoxicity than that of cisplatin against Bel-7402 cell line.     

Design and synthesis of a series of (2R)-N(4)-hydroxy-2-(3-hydroxybenzyl)-N(1)- [(1S,2R)-2-hydroxy-2,3-dihydro-1H-inden-1-yl]butanediamide derivatives as potent, selective, and orally bioavailable aggrecanase inhibitors

A pharmacophore model of the P1' site, specific for aggrecanase, was defined using the specificity studies of the matrix metalloproteinases and the similar biological activity of aggrecanase and MMP-8. Incorporation of the side chain of a tyrosine residue into compound 1 as the P1' group provided modest selectivity for aggrecanase over MMP-1, -2, and -9. A cis-(1S)(2R)-amino-2-indanol scaffold was incorporated as a tyrosine mimic (P2') to conformationally constrain 2. Further optimization resulted in compound 11, a potent, selective, and orally bioavailable inhibitor of aggrecanase.     

Synthesis and analgesic activity of (2,3-diphenyl-1H-indol-5-YL)piperazin-1-yl methanone derivatives

Series of 1,4-disubstituted piperazine and of N,N-disubstituted ethylenediamine having the 2,3-diphenyl- 1H-indole-5-carbonyl group as one of the two substituents were prepared. Compounds 3, 4, 11, 15 – 17, and 20 – 22 were tested for analgesic activity. After ip administration all compounds induced significant visceral antinociceptive activities where acetic acid-induced writhing was significantly reduced by all compounds.     

Design, synthesis and biological evaluation of some novel benzylidene-2-(4-phenylthiazol-2-yl) hydrazines as potential anti-inflammatory agents

A series of substituted benzylidene-2-(4-phenylthiazol-2-yl) hydrazines (2a–q) have been synthesized, characterized and evaluated for their anti-inflammatory activity by carrageenin-induced hind paw edema (acute inflammation) and cotton pellet granuloma (chronic inflammation) methods in rats. In carrageenin-induced hind paw edema method, compounds 2a, 2b, 2c, 2d, 2h, 2k and 2p at a dose of 20 mg kg^?1 body weight, p.o. showed excellent inhibitions (51.80–86.74 %) in between 1 and 4 h. Similarly, in cotton pellet granuloma method, compounds 2a, 2b, 2c, 2d, 2h, 2k and 2p at a dose of 20 mg kg^?1 body weight, p.o. inhibited the granuloma formation (71.71–90.19 % inhibition) which was comparable to that of standard drug, ibuprofen (90.36 % inhibition of paw volume at 3 h and 94.02 % inhibition of granuloma formation). Structure activity relationship studies showed excellent activity of the compounds containing electron withdrawing group (fluoro, chloro, bromo or nitro) in phenyl ring at C2 and/or C4 position of thiazole ring.     

Melatonergic properties of the (+)- and (-)-enantiomers of N-(4-methoxy-2,3-dihydro-1H-phenalen-2-yl)amide derivatives

N-(4-Methoxy-2,3-dihydro-1H-phenalen-2-yl)amide derivatives, conformationally restricted ligands for melatonin receptors, were synthesized by an alternative synthetic method from the corresponding 1,8-naphthalic anhydride which was transformed into the phenalenecarboxylic acid 7. A Curtius reaction on 7 gave the amino compound which was acylated to give compounds 4a-c. The (+)- and (-)-4a-c enantiomers were separated by semipreparative chiral HPLC. Compounds were evaluated for their affinity for chicken brain melatonin receptors in binding assays using 2-[125I]iodomelatonin and for their potency to lighten the skin of Xenopus laevis tadpoles. The butyramido derivative 4c was the most potent ligand (Ki = 1.7 nM). No enantioselectivity was observed with the enantiomers which were equipotent to the racemic mixture. In contrast to the reference compounds, melatonin, agomelatine (S 20098), and N-[2-(2, 7-dimethoxynaphth-1-yl)ethyl]acetamide, which were very potent at lightening the skin of X. laevis tadpoles, compounds 4a-c were inactive or weakly active (EC50 > 1 microM). In this bioassay, compound 4a was characterized as a putative antagonist of melatonin receptors.     

Structure-based design, synthesis, and molecular modeling studies of 1-(benzo[d]thiazol-2-yl)-3-(substituted aryl)urea derivatives as novel anti-Parkinsonian agents

1-(Benzo[d]thiazol-2-yl)-3-(substituted aryl)urea derivatives were designed and synthesized as our efforts to discover novel anti-Parkinsonian agents with improved pharmacological profile in haloperidol-induced catalepsy and oxidative stress in mice. All of the compounds were found to be active in alleviating haloperidol-induced catalepsy in mice. Furfuryl, 2- and/or 3-methoxy substituted phenyl derivatives emerged as potent agents. With exception of 2-chloro,5-trifluoromethyl-substituted analog, halogen-substituted derivatives exhibited moderate anti-Parkinsonian activity. Biochemical estimations of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) from brain homogenate were carried out to highlight the neuroprotective properties associated with them. Molecular docking studies of these compounds with adenosine A_2A receptor exhibited very good binding interactions and warrants further studies to confirm their binding with human A_2A receptor for the design and development of potent antagonists. Parameters for Lipinski’s rule of 5 were calculated computationally because pharmacokinetic and metabolic behaviors in the body often are linked to the physical properties of a compound. None of the synthesized compounds violated Lipinski’s rule, making them suitable drug candidate for the treatment of Parkinson’s disease.     

N-Substituted (2,3-dihydro-1,4-benzodioxin-2-yl)methylamine derivatives as D(2) antagonists/5-HT(1A) partial agonists with potential as atypical antipsychotic agents.

A series of N-substituted 1-(2,3-dihydro-1, 4-benzodioxin-2-yl)methylamine derivatives with D(2) antagonist/5-HT(1A) partial agonist activity has been prepared as potential atypical antipsychotic agents. Optimization of in vitro receptor binding activity and in vivo activity in rodent models of psychosis has led to compound 24, which showed good affinities for human D(2), D(3), and 5-HT(1A) receptors but significantly less affinity for human alpha(1) adrenoceptors and rat H(1) and muscarinic receptors. In rodents, 24 showed functional D(2)-like antagonism and 5-HT(1A) partial agonism. After oral dosing, 24 showed good activity in rodent antipsychotic tests and very little potential to cause extrapyramidal side effects (EPS), as measured by its ability to induce catalepsy in rats only at very high doses. In the light of this promising profile of activity, 24 has been selected for clinical investigation as a novel antipsychotic agent with a predicted low propensity to cause EPS.     

Design,synthesis and cytotoxic activity of novel 1-aroyl-4-(2-chloroethyl)semicarbazides

A series of aroyl derivatives of 4-(2-chloroethyl)semicarbazide were designed and synthesized to explore their antiproliferative activity against human brain carcinoma (U251) and human liver carcinoma (Hepg2) cell lines. The synthesized compounds were characterized by elemental analyses and spectroscopic data. It was established that compounds in which semicarbazide fragments are substituted with a (2-indolyl)carbonyl moiety showed a higher cytotoxic activity than the corresponding benzoyl derivatives. 1-[(5-Benzyloxy-1H-indol-2-yl)carbonyl]-4-(2-chloroethyl)semicarbazide (24) showed the highest cytotoxic activity against Hepg2 (IC₅₀= 21 μg/ml), while 4-(2-chloroethyl)-1-[(5-methoxy-1H-indol-2-yl)carbonyl]semicarbazide (23) was the most active compound against U251 (IC₅₀ = 8 μg/ml). __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 4, pp. 12–15, May, 2007.     

Synthesis and biological evaluation of new 2-(4,5-dihydro-1H-imidazol-2-yl)-3,4-dihydro-2H-1,4-benzoxazine derivatives

2-(4,5-Dihydro-1H-imidazol-2-yl)-3,4-dihydro-2H-1,4-benzoxazine derivatives and tricyclic analogues with a fused additional ring on the nitrogen atom of the benzoxazine moiety have been prepared and evaluated for their cardiovascular effects as potential antihypertensive agents. The imidazoline ring was generated by reaction of the corresponding ethyl ester with ethylenediamine. Affinities for imidazoline binding sites (IBS) I(1) and I(2) and alpha(1) and alpha(2) adrenergic receptors were evaluated as well as the effects on mean arterial blood pressure (MAP) and heart rate (HR) of spontaneously hypertensive rats. With few exceptions the most active compounds on MAP were those with high affinities for IBS and alpha(2) receptor. Among these, compound 4h was the most interesting and is now, together with its enantiomers, under complementary pharmacological evaluation.     

Synthesis of 2-(2,3-dihydro-2-oxo-1,3,4-oxadiazol-5-yl) benzo heterocycles. A novel series of orally active antiallergic agents

A series of new 2-(2,3-dihydro-2-oxo-1,3,4-oxadiazol-5-yl) benzo heterocycles has been prepared. These compounds were tested as inhibitors of antigen-induced release of histamine (AIR) in vitro from rat peritoneal mast cells (RMC) and as inhibitors of IgE-mediated rat passive cutaneous anaphylaxis in the rat (PCA). Most of this new class of antiallergic agents showed good activity in the RMC assay. The most potent compound, 3-chloro-2-(2,3-dihydro-2-oxo-1,3,4-oxadiazol-5-yl)benzo[b]thiophe ne (6t), with an I50 value of 0.2 microM, is 15 times more potent than disodium cromoglycate (DSCG) in the RMC assay. Many compounds were orally active in the PCA test, and several of these compounds showed higher potency when given in this way to that shown by DSCG when given intraperitoneally.     

Synthesis and QSAR modeling 1-[3-methyl-2-(aryldiazenyl)-2H-aziren-2-yl]ethanones as potential antibacterial agents

The present communication deals with the synthesis of a series of 1-[3-methyl-2-(aryldiazenyl)-2H-aziren-2-yl]ethanones. The compounds were synthesized in excellent yields (70–80 %), and the structures were established on the basis of consistent IR, ¹H NMR, and elemental analysis data. The purity has been ascertained by chromatographic resolution using hexane–ethyl acetate (6:4 v/v) as binary eluent. All the compounds have been tested for their antimicrobial activity against a representative panel of bacteria i.e., Bacillus subtilis, Escherichia coli, Pseudomonas diminuta, and Staphylococcus aureus using Chloramphenicol as reference drug. All the synthesized compounds were found to exhibit profound antimicrobial activity.     

Synthesis and properties of 2-(4-substituted)butyl derivatives of some 2,3-dihydro-1,3-dioxo-1H-pyrrolo[3,4-c]pyridines

The synthesis of 2-(4-substituted)butyl derivatives of 4-alkoxy-2,3-dihydro-6-methyl-1,3-dioxo-1H-pyrrolo[3,4-c]pyridine (10-15) and the results of preliminary pharmacological screening are described in this paper. All the compounds tested showed a strong analgesic action, suppressed spontaneous locomotor activity and prolonged barbiturate sleep. Except 10, all significantly decreased systolic and diastolic blood pressure.     

2-(4,5-dihydro-1H-imidazol-2-yl)indazole (indazim) derivatives as selective I(2) imidazoline receptor ligands.

A series of variously substituted 2-(4,5-dihydro-1H-imidazol-2-yl)indazoles 3a-j and 2-(4,5-dihydro-1H-imidazol-2-yl)-4,5,6,7-tetrahydroindazole 6 were prepared by the regiospecific heteroalkylation of corresponding indazoles 1a-k with 2-chloro-4,5-dihydroimidazole (2). Their affinity to imidazoline I(2) receptors and alpha(2)-adrenergic receptors was determined by radioligand binding assay carried out on P(2) membrane preparations obtained from rat whole brains. 4-Chloro-2-(4,5-dihydro-1H-imidazol-2-yl)indazole (3f, 4-Cl-indazim) showed a 3076-fold difference in affinity for the [(3)H]2BFI-labeled imidazoline I(2) receptors relative to the [(3)H]RX821001-labeled alpha(2)-adrenergic receptors. This highly selective compound should prove to be useful tool in further understanding the functions of the imidazoline I(2) receptors.     

Synthesis and screening of 2-(2-(4-substituted piperazine-1-yl)-5-phenylthiazol-4-yl)-3-aryl quinazolinone derivatives as anticancer agents

Synthesis of novel quinazolinone derivatives was performed from the reaction of N-benzoyl substituted piperazine-1-carbothioamide with 2-chloromethyl quinazolinone derivatives and screened for their in vitro cytotoxic activity by MTT assay. The cell lines used were NCI (human lung cancer cell), MCF 7 (Breast cancer cell), and HEK 293 (Normal epidermal kidney cell). Result of screening on cell line showed moderate to good anticancer activity for all the compounds. Compound 3d (IC₅₀ = 1.1 ± 0.03 μM) was found to be the most active compared to standard methotrexate (IC₅₀ = 2.20 ± 0.18 μM) and 5-florouracil (IC₅₀ = 2.30 ± 0.49 μM). Structure activity relationship of synthesized analogs suggested that the presence of NH linker with aryl moiety at the third position of quinazolinone ring was important for potent anticancer activity. Electron donating group on phenyl ring at the third position of quinazolinone ring gave better anticancer activity then unsubstituted phenyl and electron withdrawing group. Activity by substituted piperazine at 2nd position of thiazole linked with quinazolinone scaffold gave better activity in the order of H > CH₃ > CO–C₆H₅. Our findings may impart new direction to medicinal chemists and biochemists for further investigations of quinazolinone-thiazole containing anticancer agents.     

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.