Induction of intrinsic apoptosis pathway in colon cancer HCT-116 cells by novel 2-substituted-5,6,7,8-tetrahydronaphthalene derivatives.

2-Acetyl tetralin (1) reacted with N,N-dimethylformamide dimethylacetal (DMF-DMA) to afford the enaminone 3. The reaction of 3 with piperidine and morpholine afforded the trans enaminone 5a,b, respectively. Compound 3 was treated with primary aromatic amines to give secondary enaminones 6a-e. The enaminone 3 reacted with acetylglycine and hippuric acid to yield pyranones 10a, b, respectively. The reaction of enaminone 3 with 1,4-benzoquinone and 1,4-naphthoquinone gave benzofuranyl tetralin derivatives 14a,b, respectively. Also, when 3 reacted with 5-amino-3-phenyl-1H-pyrazole 15a and 5-amino-1,2,3-triazole 15b, it afforded the new pyrazolo[1,5-a]pyrimidine 17a and 1,2,3-triazolo[1,5-a]pyrimidine 17b, respectively. While the reaction of 3 with pyrimidines 18a, b resulted in the formation of pyrido[2,3-d]pyrimidine derivatives 20a, b, respectively. Investigations of the cytotoxic effect of those compounds against different human cell lines indicated that some compounds showed high selective cytotoxicity against colon cancer HCT-116 cells. Some of these compounds led to DNA damaging and fragmentation that was associated with the induction of apoptosis via mitochondrial pathway. This pathway is initiated by the impairment of mitochondrial transmembrane potential (Δψm) and in response to that the mitochondria released cytochrome c increased, that in turn activated caspase-9 and caspase-3 and induced apoptosis. Compounds 17b and 20b were promising anti-cancer agents that induced intrinsic apoptosis pathway in colon cancer cells.

Convenient synthesis, anti-inflammatory, analgesic and ulcerogenic activites of some new bis-hydrazones and pyrazole derivatives.

The reaction of acid hydrazides (1a-c) with 2-chloro-1-(4-chlorophenyl)ethanone (2a) or 2-bromo-1-(4-bromophenyl)ethanone (2b) afforded bis-hydrazones 6a-d, while the reaction of la-c with 2-oxo-N-arylpropanehydrazonoyl chlorides (3a,b) furnished N-(aryl)propanehydrazonoyl chlorides 8a-c. The reaction of the latter chlorides with sodium benzenesulfinate furnished sulfones 11a-c. On the other hand, treatment of benzothiazole-2-carbohydrazide (1c) with the appropriate ketones yielded the corresponding hydrazones 13a,b, while the reaction of 1c with 2-(ethoxymethylene)malononitrile (14) or with 2-[bis(methylthio)methylene]malononitrile (16) afforded pyrazole derivatives 15 and 17, respectively. In acute toxicity study, no mortalities were observed for the tested compounds. All the tested compounds showed significant anti-inflammatory activity, while some of them exhibited potent analgesic activity. In addition, all compounds exhibited lower ulcerogenic effects than the standard ketoprofen.

Synthesis and antiviral evalution of some novel pyrazoles and pyrazolo[3,4-d]pyridazines bearing 5,6,7,8-tetrahydronaphthalene.

The enaminone 2 was reacted with hydrazonyl halides 3a-d to afford the corresponding pyrazole derivatives (6a-d) which reacted with hydrazine hydrate to afford the new pyrazolo[3,4-d]pyridazine derivatives 7a-d, respectively. In addition, compound 2 was reacted with some primary aromatic amines to afford the corresponding secondary enaminones 10a-c and reacted with sulfapyridine or sulfapyrimidine to afford the corresponding sulfonamide derivatives 12a and 12b. Evaluation of these new compounds against rotavirus Wa strain and adenovirus type 7 showed promising antiviral activity.

Synthesis, tumor inhibitory and antioxidant activity of new polyfunctionally 2-substituted 5,6,7,8-tetrahydronaphthalene derivatives containing pyridine, thioxopyridine and pyrazolopyridine moieties.

2-Acetyl-5,6,7,8-tetrahydronaphthalene (1) was allowed to react with different aromatic aldehydes to produce the cyanopyridones 2a and 2b, which were treated with phosphorous pentasulfide to afford the corresponding thioxopyridine derivatives 3a and 3b, respectively. The reaction of 3a and 3b with ethyl bromoacetate afforded the ester derivatives 4a and 4b, while their condensation with hydrazine hydrate gave the corresponding pyrazolopyridine derivatives 5a and 5b. The reaction of the precursor 2-amino-5,6,7,8-tetrahydronaphthalene (6) with ethoxy methylenemalonic ester led to the formation of aminomethylenemalonate derivative 7. Cyclization of 7 in boiling diphenyl ether gave the derivative - ethyl 6,7,8,9-tetrahydro-4-hydroxybenzo[g]-quinoline-3-carboxylate (8) which was hydrolyzed to produce the corresponding carboxylic acid analogue 9. Further reaction of 3a with 3-chloropropane-1,2-diol and/or iodomethane produced the corresponding nicotinonitrile derivatives 10 and 11. Hydrazinolysis of derivative 11 gave the hydrazinyl derivative 12. Moreover, chlorination of compound 2a with phosphorous oxychloride led to 2-chloro nicotinonitrile derivative 13, which was refluxed with various amines to form the corresponding derivatives 5a, 14 and 15. Treatment of the pyrazolopyridine compound 5a with formic acid and acetic anhydride afforded the corresponding formamide and acetamide analogues 16 and 17, while its reaction with DMF-DMA yielded the corresponding formimidamide derivative 18. The pyridopyrazolo[1,5-a]pyrimidine derivative 19 was obtained by cyclization of 5a with acetyl acetone. The antioxidant activity evaluation of the newly synthesized compounds showed that the pyrazolopyridine derivative 5a exhibited scavenging potency higher than that obtained by ascorbic acid. Tumor inhibitory activity screening revealed that derivatives 8 and 10 showed promising potency against the liver cancer cells (HepG-2) compared to doxorubicin as a reference drug.

Synthesis of new 2-substituted 6-bromo-3-methylthiazolo[3,2-alpha]-benzimidazole derivatives and their biological activities.

1-(6-Bromo-3-methyl-1,3-thiazolo[3,2-alpha]benzimidazol-2-yl)ethanone (2) was prepared by bromination at ambient temperature of 1-(3-methylthiazolo[3,2-alpha]benzimidazol-2-yl)ethanone (1). The structure of 2 was determined by single-crystal X-ray diffraction. The precursor 5 was synthesized by heating a mixture of acetyl 2 and bromine. Various 2-substituted 6-bromo-3-methylthiazolo[3,2-alpha]benzimidazoles containing 1,3-thiazole, 1,4-benzothiazine, quinoxaline or imidazo[1,2-alpha]pyridine moieties were prepared starting from bromoacetyl 5. Taken together from the biological investigations, 2, 5, and 7a were potent immunosuppressors against both macrophages and T-lymphocytes, and 7b, 11b, and 14 were potent immunostimulators towards both types of immune cells. The results also revealed that, among others, 2 and 14 were the most significant inhibitors of LPS-stimulated NO generation, and that 5, 7a, and 7b had a weak radical scavenging activity against DPPH radicals. Moreover, 2, 5, and 7a had a concomitant strong cytotoxicity against colon carcinoma, hepatocellular carcinoma, and lymphoblastic leukemia cells. Collectively, compounds 2, 5, and 7a are multipotent compounds with promising biological activities.

Modulation of carcinogen metabolizing enzymes by new fused heterocycles pendant to 5,6,7,8-tetrahydronaphthalene derivatives.

The treatment of 2-bromo-1-(5,6,7,8-tetrahydro-naphthalen-2-yl)-ethanone (1) with pyridine, 2-methylpyridine or 4-methylpyridine afforded their corresponding pyridinum bromides 3a-c. The latter salts reacted with activated acetylene to give the corresponding indolizine derivatives 6a-c. Imidazo[1,2-a]pyridine 9a,b, quinoxaline 15, imidazo[1,2-b][1,2,4]triazole 18 and imidazo[1,2-a]benzimidazole 21 derivatives were prepared from 1 as a starting material. The investigation of the derivative influence on the carcinogen metabolizing enzymes and in the tumor initiation process revealed that 3a-c were strong inducers of epoxide hydrolase (mEH), and that 3a was an inducer of glutathione S-transferases (GSTs) and glutathione (GSH) and a potent scavenger of ROO and OH and inhibited the induced DNA damage, while 3b was a scavenger of ROO and a moderate inhibitor of DNA damage. Additionally, 6a-c significantly induced quinine reductase (QR) activity, whereas 6b induced GSTs, and 6c elevated GSH content, while both of 6b and 6c scavenged OH and inhibited the DNA damage. On the other hand, 9a possessed a moderate scavenging activity of ROO and inhibitory effect on the induced DNA damage, while 18 was a strong inducer of QR activity, scavenger of OH, and inhibitor of the DNA damage and 2 was a significant inhibitor of cytochrome P-450 1A (Cyp1A) and was an inducer of GSTs, and GSH, and a moderate inhibitor of the DNA damage.

New pyridone, thioxopyridine, pyrazolopyridine and pyridine derivatives that modulate inflammatory mediators in stimulated RAW 264.7 murine macrophage.

The reaction of 2-acetyl-5,6,7,8-tetrahydronaphthalene 1 with some aldehydes was conducted in the presence of ethyl cyanoacetate and ammonium acetate, yielded the cyanopyridones 2a-c, which react with phosphorous pentasulphide to afford the corresponding thioxopyridine derivatives 3a-c, respectively. Compounds 2a,b were converted to 2-chloropyridine derivatives 4a,b by heating with phosphorous oxychloride and phosphorous pentachloride, which were fused with hydrazine hydrate and benzyl amine to afford the corresponding pyrazolopyridine 5a,b and cyanopyridine derivatives 6a,b respectively. Compounds 2a,b also afforded 3-cyanopyridinyl oxy acetic acid ethyl ester 7a,b by reaction with ethyl bromoacetate in dry acetone in the presence of anhydrous potassium carbonate, which upon condensation with hydrazine hydrate gave the corresponding acid hydrazide 8a,b and with benzyl amine gave the corresponding acetamide 9a,b. We investigated the effect of those new compounds on the macrophage growth, macrophage binding affinity to fluorescein isothiocyanate-conjugated bacterial lipoopolysaccharide (FITC-LPS), phagocytosis of FITC-zymosan, and radical scavenging affinity against OH(), ROO*, and O(2)(-)*, in addition to their influence of the inflammatory mediators [nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), prostaglandin E-2 (PGE-2), cycloxygenase-2 (COX-2), and 5-lipoxygenase (5-LO)] in LPS-stimulated macrophages. The findings revealed that the derivatives 2b, 3b, 5a, 7b, 9a and 9b can be recognized as promising multi-potent anti-inflammatory agents.

Immunomodulatory and anticancer activities of some novel 2-substituted-6-bromo-3-methylthiazolo[3,2-a]benzimidazole derivatives.

Ethyl 6-bromo-3-methyl-1,3-thiazolo[3,2-a]benzimidazole-2-carboxylate 2 was prepared by the ambient temperature bromination of ethyl 3-methyl-1,3-thiazolo[3,2-a]benzimidazole-2-carboxylate 1. The acid hydrazide 4 was obtained by the reaction of ester 2 with hydrazine hydrate. Treatment of compound 4 with benzaldehyde or 2-thiophenaldehyde yielded the corresponding hydrazones 6a and 6b, respectively, while the reaction of acid hydrazide 4 with ethoxymethylene malononitrile (7a) or with ethyl ethoxymethylene cyanoacetate (7b) in refluxing ethanol afforded pyrazole derivatives 9a and 9b, respectively. Taken together, from the biological investigations compounds 9a and 9b were the most significant inhibitors of LPS-stimulated NO generation from Raw murine macrophage 264.7, and, as another result, compounds 2 and 4 had a weak radical scavenging activity against DPPH radicals. Moreover, 2, 4, and 9a had a concomitant strong cytotoxicity against both colon carcinoma cells (HCT-116) and hepatocellular carcinoma cells (Hep-G2) while 9b showed specific cytotoxicity only against colon carcinoma cells.