Synthesis of a series of carbon‐14 labelled 4‐aminoquinazolines and quinazolin‐4 (3H)‐ones

4‐Aminoquinazolines and quinazolin‐4 (3H)‐ones, both labelled with carbon‐14 in the 4‐position, were prepared from 2‐aminobenzonitrile‐[cyano‐¹⁴C] and 2‐aminobenzoic acid‐[carboxy ‐¹⁴C] or 2‐amino‐ benzamide‐[carboxy ‐¹⁴C], respectively, using rapid, one‐pot procedures under microwave enhanced conditions. Copyright © 2009 John Wiley & Sons, Ltd.     

3‐(3‐Ethylphenyl)‐2‐substituted hydrazino‐3H‐quinazolin‐4‐one Derivatives: New Class of Analgesic and Anti‐Inflammatory Agents

A new series of 3‐(3‐ethylphenyl)‐2‐substituted hydrazino‐3H‐quinazolin‐4‐ones were synthesized by reacting the amino group of 2‐hydrazino‐3‐(3‐ethylphenyl)‐3H‐quinazolin‐4‐one with a variety of aldehydes and ketones. The title compounds were investigated for analgesic, anti‐inflammatory and ulcerogenic index behavior. The compound 2‐(N′‐3‐pentylidene‐hydrazino)‐3‐(3‐ethylphenyl)‐3H‐quinazolin‐4‐one ( AS2 ) emerged as the most active compound in exhibiting analgesic activity and the compound 2‐(N′‐2‐pentylidene‐hydrazino)‐3‐(3‐ethylphenyl)‐3H‐quinazolin‐4‐one ( AS3 ) emerged as the most active compound in exhibiting anti‐inflammatory activity; and these compounds are moderately potent when compared with the reference standard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic potential when compared with aspirin.     

Synthesis,analgesic, anti‐inflammatory and ulcerogenic index activities of novel 2‐methylthio‐3‐substituted‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐ones

A variety of novel 2‐methylthio‐3‐substituted amino‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐ones were synthesized by reacting 3‐amino‐2‐methylthio‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐one with different aldehydes and ketones. The starting material 3‐amino‐2‐methylthio‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐one was synthesized from 2‐amino‐3‐carbethoxy‐4,5‐dimethyl thiophene. The compounds were investigated for their analgesic activity in albino mice, and for their anti‐inflammatory and ulcerogenic index activities in Wistar rats. The compound 2‐(1‐ethylpropylideneamino)‐2‐methylthio‐5,6‐dimethyl thieno [2,3‐d] pyrimidin‐4(3H)‐one (AS2) showed the most potent analgesic activity of the series. It also showed more potent anti‐inflammatory activity when compared to the reference standard, diclofenac sodium. The test compounds showed only mild ulcerogenic potential when compared to aspirin. Drug Dev Res 68:134–142, 2007. © 2007 Wiley‐Liss, Inc.     

Synthesis,molecular docking,and pharmacological evaluation of N‐(2‐(3,5‐dimethoxyphenyl)benzoxazole‐5‐yl)benzamide derivatives as selective COX‐2 inhibitors and anti‐inflammatory agents

A series of N‐(2‐(3,5‐dimethoxyphenyl)benzoxazole‐5‐yl)benzamide derivatives ( 3am ) was synthesized and evaluated for their in vitro inhibitory activity against COX‐1 and COX‐2. The compounds with considerable in vitro activity (IC₅₀ < 1 μM) were evaluated in vivo for their anti‐inflammatory potential by the carrageenan‐induced rat paw edema method. Out of 13 newly synthesized compounds, 3a , 3b , 3d , 3g , 3j , and 3k were found to be the most potent COX‐2 inhibitors in the in vitro enzymatic assay, with IC₅₀ values in the range of 0.06–0.71 μM. The in vivo anti‐inflammatory activity of these six compounds ( 3a , 3b , 3d , 3g , 3j , and 3k ) was assessed by the carrageenan‐induced rat paw edema method. Compounds 3d (84.09%), 3g (79.54%), and 3a (70.45%) demonstrated significant anti‐inflammatory activity compared to the standard drug ibuprofen (65.90%) and were also found to be safer than ibuprofen, by ulcerogenic studies. A docking study was done using the crystal structure of human COX‐2, to understand the binding mechanism of these inhibitors to the active site of COX‐2.

     

Synthesis of novel 3-butyl-2-substituted amino-3H-quinazolin-4-ones as analgesic and anti-inflammatory agents

A variety of novel 3-butyl-2-substituted amino-3H-quinazolin-4-ones were synthesized by reacting the amino group of 3-butyl-2-hydrazino-3H-quinazolin-4-one with various aldehydes and ketones. The title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic index activities. The compound 3-butyl-2-(1-methylbutylidene-hydrazino)-3H-quinazolin-4-one (AS3) emerged as the most active analgesic agent. Compound 3-butyl-2-(1-ethylpropylidene-hydrazino)-3H-quinazolin-4-one (AS2) emerged as the most active anti-inflammatory agent and is moderately more potent when compared to the reference standard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic potential when compared to aspirin.     

Synthesis and Evaluation of Novel 2‐Substituted‐quinazolin‐4(3H)‐ones as Potent Analgesic and Anti‐inflammatory Agents

A novel series of 2‐substituted‐quinazolin‐4(3H)‐ones were synthesized by reacting 3,5‐disubstituted‐anthranilic acid with acetic anhydride/benzoyl chloride, which were further reacted with different primary amines to obtain 2,6,8‐substituted‐quinazolin‐4(3H)‐ones 6a–f , 7 , 8 . All the synthesized compounds were characterized and screened for analgesic and anti‐inflammatory activities. Compounds 6,8‐dibromo‐2‐phenyl‐3‐(4′‐carboxyl phenyl)quinazolin‐4(3H)‐one 7 and 6,8‐dibromo‐2‐phenyl‐3‐(2′‐phenylethanoic acid)quinazolin‐4(3H)‐one 8 displayed good analgesic and anti‐inflammatory activity in comparison to the reference standards acetyl salicylic acid and indomethacin, respectively.     

Novel ketoprofen–antioxidants mutual codrugs as safer nonsteroidal anti‐inflammatory drugs: Synthesis,kinetic and pharmacological evaluation

Ketoprofen belongs to one of the most common nonsteroidal anti‐inflammatory drugs (NSAIDs) but its clinical usefulness has been restricted due to the high incidence of gastrointestinal complications. The release of reactive oxygen species (ROS) in NSAIDs therapy plays a major role in causing gastric complications. Antioxidants not only prevent gastric ulceration and lipid peroxidation but also preserve glutathione‐type peroxidase (GPO) activity. Therefore, the present study investigates the utility of combining anti‐inflammatory and antioxidant properties of two different compounds in a single molecule to form a series of 16 ketoprofen–antioxidant mutual codrugs. The free carboxylic group, which is believed to be one of the reasons for gastric toxicity of ketoprofen, was masked temporarily by simple and double esterification with alcoholic/phenolic–OH of natural antioxidants. In simple esterification, ketoprofen is directly linked to natural antioxidants ( IIa–h ) in the hope to obtain drugs free of gastric side effects. In an attempt to improve the in vivo lability, as well as gastric side effects, the double ester codrugs, that is, ketoprofen–antioxidant through the glycolic acid spacer (–CH₂COO; IIIa–h ), have also been designed and synthesized. The synthesized codrugs were characterized by IR, ¹H NMR, ¹³C NMR, mass spectroscopy and elemental analysis. The in vitro hydrolysis studies showed the lowest hydrolysis (highest stability) in acidic pH 1.2, whereas moderate hydrolysis was seen at pH 7.4 and significant hydrolysis in 80% human blood plasma, as indicated by their t_1/2. The pharmacological evaluation results indicate that these ketoprofen–antioxidant mutual codrugs showed the retention of anti‐inflammatory and analgesic activity with a significant reduction in the ulcer index.     

Discovery of Novel 2‐(piperidin‐4‐yl)‐1H‐benzo[d]imidazole Derivatives as Potential Anti‐Inflammatory Agents

A novel 2‐(piperidin‐4‐yl)‐1H‐benzo[d]imidazole derivative 5 with good anti‐inflammatory activity was identified from our in‐house library. Based on hit compound 5 , two series of 2‐(piperidin‐4‐yl)‐1H‐benzo[d]imidazole derivative 6a – g and 7a – h were designed and synthesized as novel anti‐inflammatory agents. Most of synthesized compounds exhibited good inhibitory activity on NO and TNF‐α production in LPS‐stimulated RAW 264.7 macrophages, in which the compound 6e showed most potent inhibitory activity on NO (IC₅₀ = 0.86 μm ) and TNF‐α (IC₅₀ = 1.87 μm ) production. Further evaluation revealed that compound 6e displayed more potent in vivo anti‐inflammatory activity than ibuprofen did on xylene‐induced ear oedema in mice. Additionally, Western blot analysis revealed that compound 6e could restore phosphorylation level of IκBα and protein expression of p65 NF‐κB in LPS‐stimulated RAW 264.7 macrophages.     

1‐[(2,3‐Dihydro‐1‐benzofuran‐2‐yl) methyl]piperazines as novel anti‐inflammatory compounds: Synthesis and evaluation on H3R/H4R

The histamine receptors (HRs) are members of G‐protein‐coupled receptor superfamily and traditional targets of huge therapeutic interests. Recently, H₃R and H₄R have been explored as targets for drug discovery, including in the search for dual‐acting H₃R/H₄R ligands. The H₄R, the most recent histamine receptor, is a promising target for novel anti‐inflammatory agents in several conditions such as asthma and other chronic inflammatory diseases. Due to similarity with previously reported ligands of HRs, a set of 1‐[(2,3‐dihydro‐1‐benzofuran‐2‐yl)methyl]piperazines were synthesized and evaluated in competitive binding assays as H₃R/H₄R ligands herein. The results showed the compounds presented affinity (K_i) for H₃R/H₄R in micromolar range, and they are more selective to H₃R. All the compounds showed no important cytotoxicity to mammalian cells. The phenyl‐substituted compound LINS01005 has shown the higher affinity of the set for H₄R, but no considerable selectivity toward this receptor over H₃R. LINS01005 showed interesting anti‐inflammatory activity in murine asthma model, reducing the eosinophil counts in bronchoalveolar lavage fluid, as well as the COX‐2 expression. The presented compounds are valuable prototypes for further improvements to achieve better anti‐inflammatory agents.     

Synthesis, antitubercular and anticancer activities of substituted furyl-quinazolin-3(4H)-ones

Some novel substituted-3-{[(1E)-(substituted-2-furyl)-methylene]amino}quinazolin-4(3H)-one (5, 6, 7) a-f were synthesized by a multi-step process. These synthesized compounds are characterized by various spectroscopic techniques and evaluated for their antitubercular and anticancer activities. Biological activity indicated that some of the title compounds are potent antitubercular and anticancer agents.     

Synthesis of labelled N‐(4‐hydroxy‐[14C(U)]phenyl)‐2‐[2,3‐dihydro‐3‐oxo‐l,2‐benzisothiazol‐2‐yl‐1,1‐dioxide]acetamide

The amidation of 2‐[1,1‐dioxide‐3‐oxo‐1,2‐benzisothiazole‐2(3H)‐yl] acetyl chloride with carbon‐14‐labelled 4‐amino‐[¹⁴C(U)]phenol in NaOAc‐HOAc buffer solution at ?10°C gave N‐(4‐hydroxy‐[¹⁴C(U)]phenyl)‐2‐[2,3‐dihydro‐3‐oxo‐1,2‐benziso‐thiazol‐2‐yl‐1,1‐dioxide]acetamide in 82% yield. Subsequent hydrolysis with aqueous 0.5 N NaOH solution afforded the ring opened product N‐(4‐hydroxy‐[¹⁴C(U)]‐phenyl)‐2‐[2‐carboxy‐phenylsulfonamido]acetamide in 80% yield. Copyright © 2005 John Wiley & Sons, Ltd.     

Syntheses of [14C]‐labeled 2‐(3‐chlorophenyloxy)‐3‐[3‐(3‐hydroxy) pyridin‐4‐yl propoxy]pyridine,a phosphodiesterase 4 inhibitor and its metabolites

We describe here the synthesis of [¹⁴C]‐2‐(3‐chlorophenyloxy)‐3‐[3‐(3‐hydroxy)pyridin‐4‐yl propoxy]pyridine (1), a phosphodiesterase 4 inhibitor. [¹⁴C]‐Labeled 1 was prepared in three steps from [¹⁴C]‐2‐bromopyridin‐3‐ol in an overall yield of 32%. Preparation of [¹⁴C]‐labeled 2 and 3, two metabolites of 1, is also described. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis and Antitubercular Activity of 2‐(substituted phenyl/benzyl‐amino)‐6‐(4‐chlorophenyl)‐5‐(methoxycarbonyl)‐4‐methyl‐3,6‐dihydropyrimidin‐1‐ium Chlorides

A series of 2‐(substituted phenyl/benzyl‐amino)‐6‐(4‐chlorophenyl)‐5‐(methoxycarbonyl)‐4‐methyl‐3,6‐dihydropyrimidin‐1‐ium chlorides 7–13 and 15 was synthesized in their hydrochloride salt form. The title compounds were characterized by FT‐IR, NMR (¹H and ¹³C) and elemental analysis. They were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv, multidrug resistance tuberculosis and extensively drug resistance tuberculosis by agar diffusion method and tested for the cytotoxic action on peripheral blood mononuclear cells by MTT assay. Among all the tested compounds in the series, compounds 7 and 11 emerged as promising antitubercular agents at 16 μg/mL against multidrug resistance tuberculosis and over 64 μg/mL against extensively drug resistance tuberculosis. The conformational features and supramolecular assembly of the promising compounds 7 and 11 were determined by single crystal X‐ray study.     

Synthesis of novel substituted 7-(benzylideneamino)-4-methyl-2H-chromen-2-one derivatives as anti-inflammatory and analgesic agents

A series of novel Schiff' base-containing a 7-amino-4-methylcoumarin moiety have been synthesized III a-l, characterized by spectroscopic data and studied for their anti-inflammatory and analgesic activity. The results of the anti-inflammatory and analgesic activity evaluation of 7-(substituted benzylideneamino)-4-methyl-2H-chromen-2-one derivatives III a-l proved to be comparable or more potent with respect to the reference drugs. In particular, compounds 7-(4-chlorobenzylideneamino)-4-methyl-2H-chromen-2-one III f, 7-(2,4-dichlorobenzylideneamino)-4-methyl-2H-chromen-2-one III g and 7-(4-bromobenzylideneamino)-4-methyl-2H-chromen-2-one III h exhibited potent anti-inflammatory and analgesic activity.     

Synthesis and pharmacological evaluation of some 4-oxo-quinoline-2-carboxylic acid derivatives as anti-inflammatory and analgesic agents

The synthesis and the pharmacological activity of a series of 1-aroyl derivatives of kynurenic acid methyl ester (4-oxo-quinolin-2-carboxy methyl (KYNA) esters), structurally related to NSAID indomethacin are described. The derivatives were screened in vivo for anti-inflammatory and analgesic activities. Most of the compounds exhibited good anti-inflammatory and analgesic activities. An automatic docking of the synthesized compounds was performed using X-ray structures of COX-1 and COX-2. Docking results are in good accordance with the experimental biological data.     

Synthesis and in‐vitro Cytotoxicity of Poly‐functionalized 4‐(2‐Arylthiazol‐4‐yl)‐4H‐chromenes

A new series of 4‐aryl‐4H‐chromenes bearing a 2‐arylthiazol‐4‐yl moiety at the 4‐position were prepared as potential cytotoxic agents. The in‐vitro cytotoxic activity of the synthesized 4‐aryl‐4H‐chromenes was investigated in comparison with etoposide, a well‐known anticancer drug, using MTT colorimetric assay. Among them, the 2‐(2‐chlorophenyl)thiazol‐4‐yl analog 4b showed the most potent activity against nasopharyngeal epidermoid carcinoma KB, medulloblastoma DAOY, and astrocytoma 1321N1, and compound 4d bearing a 2‐(4‐chlorophenyl)thiazol‐4‐yl moiety at the 4‐position of the chromene ring exhibited the best inhibitory activity against breast cancer cells MCF‐7, lung cancer cells A549, and colon adenocarcinoma cells SW480 with IC₅₀ values less than 5 μM. The ability of compound 4b to induce apoptosis was confirmed in a nuclear morphological assay by DAPI staining in the KB and MCF‐7 cells.     

Design,Synthesis, and Antitumor Activity of (E,Z)‐1‐(dihydrobenzofuran‐5‐yl)‐3‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)‐2‐propen‐1‐ones

A series of (E,Z)‐1‐(dihydrobenzofuran‐5‐yl)‐3‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)‐2‐propen‐1‐ones ( C1 – C35 ) were designed and synthesized, and the structures of compounds (Z)‐ C27 and (Z)‐ C29 were confirmed by single‐crystal X‐ray diffraction. The antitumor activities of these novel compounds against cervical cancer (HeLa), lung cancer (A549), and breast cancer (MCF‐7) cell lines were evaluated in vitro. Majority of the title compounds exhibited strong antitumor activities and were much more promising than the positive control Taxol, which were also accompanied by lower cytotoxicity to normal cells. In particular, compounds (E,Z)‐ C24 exhibited the most consistent potent activities against three neoplastic cells with IC₅₀ values ranging from 3.2 to 7.1 μm . Further researches demonstrated that compounds (E,Z)‐ C24 could induce cell apoptosis and arrest cell cycle at the G2/M and S phases. Meanwhile, the structure–activity relationship between the configurations and cytotoxicity of the compounds was also investigated.