Synthesis of 4-(2-hydroxymethylaryl)coumarins

New 4-(2-hydroxymethylaryl)coumarins were prepared using the Suzuki—Miyaura cross-coupling at the key step. According to X-ray diffraction data, the compounds obtained are structural analogs of the natural stilbene combretastatin A-4, which exhibits potent antitumor activity.     

Synthesis and reactions of 4-(arylhydrazino)coumarins

The interaction of 4-hydroxycoumarin with phenyl-, 2-chlorophenyl- and 4-bromophenyhydrazine hydrochlorides in the presence of triethylamine led in all cases to the corresponding 4-(arylhydrazino)-coumarins and 1-aryl-3-(2-hydroxyphenyl)-2H-pyrazolin-5-ones. 4-(Arylhydrazino)coumarins reacted with 4-chlorobenzaldehyde in the presence of piperidine acetate to give the corresponding 2-aryl-3-(4-chlorophenyl)[1]benzopyrano[4,3-b]pyrazol-4-ones. The reaction of 4-(4-bromophenylhydrazino)-coumarin with 4-chlorobenzaldehyde in the presence of piperidine acetate and an excess of piperidine gave 2-(4-bromophenyl)-5-(4-chlorophenyl)-3-(2-hydroxyphenyl)-4-(piperidinocarbonyl)pyrazole, but the reaction of phenyl- and 4-(2-chlorophenylhydrazino)coumarins with 4-chlorobenzaldehyde gave 1-aryl-5-(4-chlorophenyl)-3-(2-hydroxyphenyl)-4-(1-piperidino)carbonyl-4,5-dihydropyrazoles.     

Synthesis,reactions and biological evaluation of some 1,2,4-triazine derivatives

6-Substituted benzyl-4-phenyl-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazin-5-ones 3a-d were prepared and converted into their corresponding 3-methylthio derivatives 4a-d . Reaction of compounds 4a-d with hydrazine hydrate gave the corresponding 4-amino-3-anilino-4,5-dihydro-1,2,4-triazin-5-ones 5a-d . 6-Substituted benzyl-4-phenyl-2,3,4,5-tetrahydro-1,2,4-triazin-3,5-diones 9a-c were synthesized and allowed to react with hydrazine hydrate to give the corresponding 6-substituted benzyl-4-amino-2,3,4,5-tetrahydro-1,2,4-triazin-3,5-diones 10a-c . The biological evaluation of some of these triazines is described. All compounds were screened for antiviral, antibacterial, antimycobacterial, antifungal and antiyeast activity. No important biological activity was found.     

Novel Bis(1,2,4-oxadiazolyl) Fused Thiazole Derivatives: Synthesis and Anticancer Activity

A novel series of bis-1,2,4-oxadiazole fused benzothiazole derivatives 9a–9j are synthesized, and their structures are confirmed by ¹H and ¹³C NMR, and mass spectral data. All products are evaluated in vitro for their anticancer potential against a panel of four human cancer cell lines such as lung cancer (A549), breast carcinoma (MCF-7), melanoma (A375), and colon cancer (HT-29). The combretastatin-A4 is used as standard drug. All compounds 9a–9j exhibit significant anticancer activity with IC₅₀ values ranging from 0.11±0.01 to 14.6±3.89 μM. Among these, compounds 9a–9d, 9h, 9i demonstrate more potent activity than the control.

     

Synthesis and biological evaluation of (S)-4-aminoquinazoline alcohols

A simple synthetic method for the preparation of enantiomerically pure (S)-4-aminoquinazoline alcohols from (S)-quinazolinone alcohols by key steps including chlorination, nucleophilic ipso substitution, and deacetylation is presented. Mutagenic and antimutagenic properties of the (S)-4-aminoquinazoline alcohols were investigated by using Salmonella typhimurium TA1535, and Escherichia coli WP2uvrA tester strains at 0.01, 0.1, and 1 μg/plate concentrations. (S)-4-aminoquinazoline alcohols were found to be genotoxically safe at the tested concentrations. Among the tested (S)-4-aminoquinazoline alcohols, the best antimutagenic activity was obtained with a methyl derivative at 0.1 μg/plate dose.     

Synthesis and biological activity of some novel derivatives of 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole

To discover new 1,2,4-triazole derivatives which may possess significant biological activities, we synthesized a series of novel 6-aryl-3-(D-galactopentitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galactopentitol-1-yl)-3-mercapto-4H-1,2,4-triazoles from 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole. All the title compounds were characterized by elemental analysis, IR, 1H- and 13C-NMR. Plant growth-regulating activity tests showed that these compounds have remarkable effects on the growth of radish and wheat.     

Synthesis and biological evaluation of some novel Schiff's bases from 1,2,4-triazole

We have synthesized a number of novel Schiff's bases from 4-amino-3-(D-glucoheptonic-hexitol-1-yl)-1H-1,2,4-triazole-5-thione. By attaching D-glucoheptonic-hexitol-1-yl residues to 1,2,4-triazole at the 3-position, the solubility of the title compounds has been improved greatly. All the products have been characterized by elemental analysis, IR, 1H-NMR, 13C-NMR and MS. The plant-growth regulating effects of the title compounds were examined. From the biological activity results, we found that most compounds showed weak to moderate activities.     

3-（2-呋喃基）-4-芳基-1，2，4-三唑啉-5-硫酮的合成及生物活性

1-（2-呋喃甲酰基）-4-芳基氨基硫脲经过环化反应，制备了一系列新的化合 物3-（2-呋喃基）-4-芳基-1，2，4-三唑啉-5-硫酮类化合物，并通过元素分析和 IR，^1H NMR等波谱数据确证了上述化合物的结构。初步的生物活性实验表明其中 有些化合物的具有非常好的植物生长调节活性。     

Synthesis and biological activity of some 3-(4-(substituted)-piperazin-1-yl)cinnolines

A new series of 6-substituted-4-methyl-3-(4-arylpiperazin-1-yl)cinnolines 8-10 were synthesized as potential antifungal agents via intramolecular cyclization of the respective 1-(2-arylhydrazono)-1-(4-arylpiperazin-1-yl)propan-2-ones 5-7, mediated by polyphosphoric acid (PPA). The amidrazones themselves were synthesized via direct interaction of the appropriate hydrazonoyl chlorides 4a-d with the corresponding N-substituted piperazine in the presence of triethylamine. The structures of the new prepared compounds were confirmed by elemental analyses, (1)H-NMR, (13)C-NMR, and ESI-HRMS spectral data. The antitumor, antibacterial, and antifungal activity of the newly synthesized compounds was evaluated.     

Synthesis of 4-(4-phenyl-3-pyrazolyl)-4H-1,2,4-triazoles

4-(4-PhenyI-3-pyrazolyl)-4H-1,2,4-triazoles and 4-phenyl-5-(4H-1,2,4-triazol4-yl)-3-pyrazolols were prepared by the reaction of formylhydrazine on α-phenyl-α-cyanoacetaldehydes and ethyl α-phenyl-α-cyanoacetates.     

Synthesis and biological evaluation of some heterocyclic scaffolds based on the multifunctional N-(4-acetylphenyl)-2-chloroacetamide

The chloroacetamide derivative, 1 , was used as a versatile precursor for the synthesis of various types of N-aryl-2-(benzothiazol-2-ylthio)acetamide derivatives. The reaction of 1 with 2-mercaptobenzothiazole followed by condensation reaction of the produced sulfide with phenylhydrazine, 2-cyanoacetohydrazide, and/or thiosemicarbazide furnished the conforming condensation products, 4 , 7 , and 10 , respectively. Treatment of the phenylhydrazone product, 4 , with Vilsmeier formylation reagent (POCl₃/DMF) yielded the corresponding 4-formylpyrazole derivative, 5 . The thiosemicarbazone product, 10 , was reacted with ethyl bromoacetate to furnish the thiazolin-4-one derivative, 11 . The substitution reactions of chloroacetamide derivative, 1 , with 2-mercapto-4,6-dimethylnicotinonitrile and 6-amino-2-mercaptopyrimidin-4-ol, were explored to identify the sulfide products, 14 and 17 . Cyclization of 14 into its corresponding thieno[2,3-b]pyridine compound, 15 , was performed using sodium ethoxide. The thiosemicarbazone, 10 , and sulfide derivative, 14 , were found to be the most potent antibacterial compounds against Escherichia coli and Staphylococcus aureus, exhibiting growth inhibitory activities of 80.8% and 91.7%, respectively. Moreover, the thiosemicarbazone, 10 , displayed the most significant antioxidant activity with inhibitory activity of 82.6%, which comes close to the antioxidant activity of L-ascorbic acid.     

Synthesis and biological evaluation of (-)-laulimalide analogues

[reaction: see text] The syntheses of five laulimalide analogues are described, incorporating modifications at the C(16)-C(17)-epoxide, the C(20)-alcohol, as well as the C(1)-C(3)-enoate of the parent natural product. The resultant analogues are active in drug-sensitive HeLa and MDA-MB-435 cell lines. Significantly, like laulimalide, these analogues are poor substrates for the drug transport protein P-glycoprotein (Pgp) and are thus effective against Taxol-resistant cell lines.     

Synthesis and spectral-luminescence properties of 7-diethylamino-4-(2-arylethenyl)coumarins

A number of 7-diethylamino-4-(2-arylethenyl)coumarins were obtained by condensation of 7-diethylamino-4-methylcoumarin with aromatic aldehydes, while only a product of addition to the carbon—nitrogen double bond is formed with benzalaniline. The spectral-luminescence properties of the compounds obtained were investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 319–322, March, 1991.     

Synthesis of 5-Aryl-3-(4-pyridyl)-1,2,4-oxadiazoles

The title oxadiazoles were formed in the reaction of N-(4-pyridylmethyl)arylamides with nitrosyl chloride in low yields.     

Synthesis and biological activities of novel dialkyl (4-trifluoromethylphenylamino)-(4-trifluoromethyl or 3-fluorophenyl) methylphosphonates

A series of novel dialkyl (4-trifluoromethylphenylamino)-(4-trifluoromethyl or 3-fluorophenyl) methylphosphonates 3 were synthesized through the reaction of 3-fluorobenzaldehyde or 4-trifluoromethylbenzaldehyde and 4-trifluoromethylaniline with dialkyl phosphite by microwave irradiation using boron trifluoride-ether catalyst and their structures were clearly verified by spectroscopic data (IR, ¹H NMR and elemental analysis). The results of bioassay showed that these title compounds possess potential anticancer activities in vitro by MTT method. At the same time, we found these title compounds exhibit moderate antiviral activity against tobacco mosaic virus.     

Synthesis and biological evaluation of (-)-dictyostatin and stereoisomers

Total syntheses of (−)-dictyostatin, 6,16-bis-epi-dictyostatin, 6,14,19-tris-epi-dictyostatin, and a number of other isomers and analogs are reported. Three main fragments—top, middle, and bottom—were first assembled and then joined by olefination or anionic addition reactions. After appending the two dienes at either end of the molecule, macrolactonization and deprotection completed the syntheses. The work proves both the relative and absolute configurations of (−)-dictyostatin. The compounds were evaluated by cell-based measurements of increased microtubule mass and antiproliferative activity, and in vitro tubulin polymerization assays as well as competitive assays with paclitaxel for its binding site on microtubules. These assays showed dictyostatin to be the most potent of the agents and further showed that the structural alterations caused from 20- to >1000-fold decreases in activity.     

Synthesis and reactions of some 6-(2-hydroxy-1-naphthyl)-1,2,4-triazines

4,5-Benzocoumaran-2,3-dione condenses with semicarbazide and thiosemicarbazide at the 3-position and the products obtained were converted to the corresponding 6-(2-hydroxy-1-naphthyl)-1,2,4-triazines. Reactions of these triazines with some reagents are described.