Synthesis and structural analyses of 3-acetamido-1,4-di-O-acetyl-2,3,5-trideoxy-5-C-(isopropylphosphinyl)-D-erythro-pentopyranoses

1H NMR spectroscopy of phosphorus containing hetero sugars (phospha sugars), revealed the alpha and beta configurations and chair conformations for 3-acetamido-1,4-di-O-acetyl-2,3,5-trideoxy-5-C-(isopropylphosphinyl)-alpha- and beta-D-erythro-pentopyranoses. The conformation of the title compounds was determined by 1H NMR as 1C4 in CDCl3 and the conformation was in accord with that in solid state determined by X-ray crystallographic analysis.     

Design and Synthesis of 2′-Deoxy-2′-[(1,2,3)Triazol-1-Yl]Uridines Using Click Chemistry Approach

A series of novel nucleosides bearing a 1,2,3-triazole moiety at the 2′-position of the sugar moiety has been synthesized starting from 2′-azidouridine and using the copper (I)-catalyzed Huisgen–Sharpless–Meldal 1,3-dipolar cycloaddition reaction. The reactions proceeded in overall yield of 52–82% and gave almost exclusively the 1,4-disubstituted 1,2,3-triazoles. The 2′-azidouridine was synthesized from uridine in two steps, and reacted with a variety of differently substituted alkynes to give the desired 2′-triazole-substituted uridine derivatives.     

Synthesis of 2-bromomethyl-3-hydroxy-2-hydroxymethyl-propyl pyrimidine and theophylline nucleosides under microwave irradiation. Evaluation of their activity against hepatitis B virus

Alkylation of 2-methylthiopyrimidin-4(1H)-one (1a) and its 5(6)-alkyl derivatives 1b-d as well as theophylline (7) with 2,2-bis(bromomethyl)-1,3-diacetoxypropane (2) under microwave irradiation gave the corresponding acyclonucleosides 1-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]-2-methyl-thio pyrmidin-4(1H)-ones 3a-d and 7-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]theophylline (8), which upon further irradiation gave the double-headed acyclonucleosides 1,1 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis[(2-(methylthio)-pyrimidin-4(1H)-ones] 4a-c, and 7,7 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis(theophylline) (9). The deacetylated derivatives were obtained by the action of sodium methoxide. The activity of deacetylated nucleosides against Hepatitis B virus was evaluated. Compound 5b showed moderate inhibition activity against HBV with mild cytotoxicity.     

Alkyne-azide click chemistry mediated carbanucleosides synthesis

Hitherto unknown 1,4-disubstituted-[1,2,3]-triazolo-4',4'-dihydroxymethyl-3'-deoxy carbanucleosides were synthesized based on a "click approach." Various alkynes were introduced on a key azido intermediate by the "click" 1,3-dipolar Huisgen cycloaddition. Their antiviral activities and cellular toxicities were evaluated on vaccinia virus. None of the synthesized compounds exhibited a significant antiviral activity.     

New conformationally locked bicyclic N,O-nucleoside analogues of antiviral drugs

In order to obtain rigidity within the sugar moiety of nucleosides, the bicyclic pyrimidine derivatives of N,O-isoxazolidines were designed and synthesized by using 1,3-dipolar cycloaddition of Delta(1)-pyrrolidine-1-oxide and the appropriate vinyl-nucleobases.     

Synthesis of 2,6,7-trideoxy-7-C-(2,4-dichlorophenyl)-D-xylo-heptonic acid and 6-(2,4-dichlorophenyl)-D-xylo-2,3,4-tri-hydroxyhexanesulfonic acid.

2,4-O-Benzylidene-L-xylose was converted via a Wittig reaction into Z-2,4-O-benzylidene-5,6-dideoxy-6-C-(2,4-dichlorophenyl)-D-xylo-hex-5-++ +enitol (17), which, on hydrogenation, gave 5,6-dideoxy-6-C-(2,4-dichlorophenyl)-D-xylo- hexitol (33). tert-Butyldimethylsililation of the primary hydroxyl group of 33, followed by 4-methoxybenzylation, and desilylation afforded 5,6-dideoxy-6-C-(2,4-dichlorophenyl)-2,3,4-tri-O-(4-methoxybenzyl)-D-xyl o- hexitol (54). A Mitsunobu-type reaction of 54 replaced HO-1 by cyanide to give, after hydrolysis and hydrogenolysis, 2,6,7-trideoxy-7-C-(2,4- dichlorophenyl)-D-xylo-heptono-1,4-lactone (55). Mesylation of 33 and then acetylation gave 2,3,4-tri-O-acetyl-5,6-dideoxy- 6-C-(2,4-dichlorophenyl)-1-O-methanesulfonyl-D-xylo-hexitol (63), which was converted via its 1-thiobenzoate into bis[1,5,6-trideoxy-6-C-(2,4-dichlorophenyl)-D-xylo-hexitol] 1,1'-disulfide (65). Acetylation of 65, followed by permanganate oxidation and deacetylation, afforded sodium 6-(2,4-dichlorophenyl)-D-xylo- 2,3,4-trihydroxy-hexanesulfonate (67). Both 57 (obtained from 55 by hydrolysis with NaOH) and 67 are weak inhibitors of HMG-CoA reductase.     

Synthesis of polydeoxygenated and iodinated disaccharides.]

3-Amino-polydeoxy disaccharides have been prepared by condensation of a glycal with methyl 2,3,6-trideoxy-alpha-L-erythro-(or threo)-hex-2-enopyranoside in the presence of N-iodosuccinimide. After acid hydrolysis of the glycoside, 1,4-addition of hydrazoic acid to the corresponding hex-2-enopyranose led to 3-azido-disaccharides which were acetylated. Reduction of the azido group gave 2,2'-dideoxy- or 2,2'-dideoxy-2'-iodo compounds. Condensation of O-(3,4-di-O-acetyl-2,6-dideoxy-2-iodo-alpha-L-manno-hexopy-rano syl)-(1----4)-1- O-acetyl-2,3,6-trideoxy-3-trifluoroacetamido-alpha-L-arabino-he xopyranose with daunomycinone, followed by 3',4'-O-deacetylation produced the new anthracycline, 7-O-[O-(2,6-dideoxy-2-iodo-alpha-L-manno-hexopyranosyl)-(1----4)-2,3,6- trideoxy-3-trifluoroacetamido-alpha-L-arabino-hexopyranosyl]-da uno-mycinone.     

Rearrangement of unsaturated 2,4-O-benzylidenehexitol derivatives into C-glycosylbenzene derivatives.

Acetolysis of (Z)-1,3-di-O-acetyl-2,4-O-benzylidene-6-C-(2,4-dichlorophenyl)-D-xylo-he x- 5-enitol (3) afforded (E)-1,2,3,4-tetra-O-acetyl-6-C-(2,4-dichlorophenyl)-D-xylo-hex-5-enit ol and 2-C-[(R)-acetoxy(2,4-dichlorophenyl)methyl]-3,4,6-tri-O-acetyl-2-deoxy- beta-L-galacto- and -beta-L-gulo-hexopyranosylbenzene. The mechanism of this new rearrangement was studied by exchanging the substituents at C-1 and C-3 in 3 and those of the aromatic ring attached to C-6.     

New cerebrosides from Euphorbia peplis L.: antimicrobial activity evaluation

The less polar fraction of the methanolic extract from the plant Euphorbia peplis L. exhibited interesting antifungal and antitubercular activity. A complex mixture of four glucocerebrosides was responsible for this activity. Two new cerebrosides were isolated for the first time from Euphorbiaceae, 4 was assigned as 1-O-(beta-D-glucopyranosyl)-(2S,3S,4E,8E)-2N-[(2'R)-2'-hydroxy-hexadecanoyl]-4 (E), 8 (E)-octadecadiene-1,3-diol and 3 as the 1-O-(beta-D-glucopyranosyl)-(2S,3S,4R,8Z)-2N-[(2'R)-2'-hydroxytetracosanoyl]-8 (Z)-octadecene-1,3,4-triol. The structures were determined on the basis of chemical and spectroscopic evidences. Mass spectrometry of dimethyl disulfide derivatives was useful for the determination of the double-bond positions in the long-chain bases.     

Synthesis and antitumor activity of cytosine and adenine nucleosides of unsaturated 5-(aminoacyl)aminopentofuranoses

Direct synthesis of the 1- and 9-(5-azido-2,3,5-trideoxy-β-D-glycero-pent-2-enofuranosyl) derivatives (3a and 3b) of cytosine and adenine, respectively, has been accomplished via treatment of the corresponding 2′,3′-unsaturated nucleosides (1a and 1b) with triphenylphosphine and carbon tetrabromide in the presence of lithium azide. Members of a new type of (aminoacyl)amino nucleoside, the 1- and 9-[5-(aminoacyl)amino-2,3,5-trideoxy-β-D-glycero-pent-2-enofuranosyl] derivatives of cytosine and adenine, respectively, have been obtained by condensation of the corresponding, unsaturated amino nucleosides with the active esters of several amino acid derivatives, followed by deprotection. These nucleosides were examined for in vivo antitumor activity against leukemia L-1210 and Sarcoma 180 (solid tumor) in mice; none of them exhibited antitumor activity against L-1210 in mice, but compounds 1a, 3a, and 1-[2,3,5-trideoxy-5-(L-methionyl)amino-β-D-glycero-pent-2-enofuranosyl]cytosine exhibited weak activity against Sarcoma 180 (solid tumor).     

Synthesis of Novel Bi-Heterocycles as Valuable Anti-Diabetic Agents: 2-({5-((2-Amino-1,3-Thiazol-4-yl)methyl)-1,3,4-Oxadiazol-2-yl}sulfanyl)-N-(Substituted)acetamides

Russian Journal of Bioorganic Chemistry - The synthesis of a new series of S-substituted acetamides derivatives of 5-[(2-amino-1,3-thiazol-4-yl)methyl]-1,3,4-oxadiazol-2-thiol were synthesized and...     

Synthesis of some new hybride molecules containing several azole moieties and investigation of their biological activities

1,2,4-Triazole-3-one prepared from tryptamine was converted to the corresponding carbothioamides by several steps. Their treatment with ethyl bromoacetate or 4-chlorophenacyl bromide produced the corresponding 5-oxo-1,3-thiazolidine or 3-(4-chlorophenyl)-1,3-thiazole derivatives. Acetohydrazide derivative that was obtained starting from tryptamine, was converted to the corresponding Schiff basis and sulfonamide by the treatment with suitable aldehydes and benzensulphonyl chloride, respectively. 2-[(4-Amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazole-3-yl)methyl]-4-[2-(1H-indole-3-yl)ethyl]-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-one was synthesized starting from hydrazide via the formation of the corresponding 1,3,4-oxadiazole compound, while the other bitriazole compounds were obtained by intramolecular cyclisation of carbothioamides in basic media. The treatment of 1,2,4-triazole or 1,3,4-oxadiazole compound with several amines generated the corresponding Mannich bases. Ethyl (2-amino-1,3-thiazole-4-yl)acetate was converted to the corresponding 1,3,4-oxadiazole derivative, arylidenehydrazides, 1,2,4-triazole-3-one and 5-oxo-1,3-oxazolidine derivatives by several steps. The structural assignments of new compounds were based on their elemental analysis and spectral (FT IR, ¹H NMR, ¹³C NMR and LC-MS) data. The antimicrobial, antilipase and antiurease activity studies revealed that some of the synthesized compounds showed antimicrobial, antilipase and/or antiurease activity.     

Synthesis of novel steroidal 17α-triazolyl derivatives via Cu(I)-catalyzed azide-alkyne cycloaddition, and an evaluation of their cytotoxic activity in vitro

Regioselective Cu(I)-catalyzed 1,3-dipolar cycloaddition of steroidal 17α-azides with different terminal alkynes afforded novel 1,4-disubstituted triazolyl derivatives in good yields in both the estrone and the androstane series. The antiproliferative activities of the structurally related triazoles were determined in vitro on three malignant human cell lines (HeLa, MCF7 and A431), with the microculture tetrazolium assay.     

Efficient synthesis and in vitro cytostatic activity of 4-substituted triazolyl-nucleosides

We report herein an efficient synthesis of 4-substituted triazolyl-nucleosides and their in vitro cytostatic activity. The synthesis is based on a straightforward 1,3-dipolar cycloaddition between 1-azido-ribose 2 and terminal alkynes under a cooperative effect of microwave activation and copper (I) catalysis. All cycloadducts were obtained in nearly quantitative yield after a short reaction time (1 to 2min). After removal of acetyl protecting groups, the free nucleosides were evaluated against L1210, Molt4/C8, and CEM tumor cell lines. Structure-activity relationship study shows that the substituent on the triazole ring has a major effect since nucleosides 4c and 4g, containing, respectively, a long alkyl chain and an aryl donor group are the most active compounds in this series.     

Construction of a branched chain at C-3 of a hexopyranoside. Synthesis of miharamycin sugar moiety analogs

Synthesis of the conveniently protected epimer at C-3' of the miharamycin sugar moiety was accomplished starting from the corresponding 3,3'-spiroepoxide. Reaction of the epoxide with lithium cyanide, followed by hydrolysis and spontaneous cyclization, afforded the intermediate deoxylactone methyl 4,6-O-benzylidene-3-C-(carboxymethyl)-alpha-D-glucopyranoside-3',2-lacto ne (8). Stereoselective hydroxylation with MoO5 x py x HMPA, reduction with lithium aluminum hydride and cyclization with diethyl azodicarboxylate-triphenylphosphine gave the target molecule methyl 2,3'-anhydro-4,6-O-benzylidene-3-C-[(R)-1,2-dihydroxyethyl]-alpha -D-glucopyranoside (5). Direct reduction of 8 gave other analogs having no C-3' hydroxyl group together with having a C-3' hydroxyl group (hemiacetal). In addition, C-3' epimers were also synthesized through C-3', C-3' dihydroxy analogs. Wittig reaction of an appropriate ketosugar with [(ethoxycarbonyl)methylene]triphenylphosphorane leading to a 7:3 Z/E mixture, followed by hydroxylation with osmium tetroxide, reduction and cyclization afforded the target molecule 5 and the miharamycin sugar moiety methyl 2,3'-anhydro-4,6-O-benzylidene-3-C-[(S)-1,2-dihydroxyethyl]-alpha -D-glucopyranoside. Examination of X-ray data for 5 and its NMR spectroscopy data allowed us to explain a contradiction reported in the literature.     

Synthesis and Evaluation of Anticonvulsant Activity of Some Schiff Bases of 7‐Amino‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one

A variety of 1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one azomethines and 1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one benzamide were prepared, characterized and evaluated for the anticonvulsant activity in the rat using picrotoxin‐induced seizure model. The prepared 1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one azomethine derivatives emerged potentially anticonvulsant molecular scaffolds exemplified by compounds, 7‐{(E)‐[(4‐nitrophenyl)methylidene]amino}‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one, 7‐[(E)‐{[4‐(dimethylamino)phenyl]methylidene}amino]‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one, 7‐{(E)‐[(4‐bromo‐2,6‐difluorophenyl)methylidene]amino}‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one and 7‐[(E)‐{[3‐(4‐fluorophenyl)‐1‐phenyl‐1H‐pyrazol‐4‐yl]methylidene}amino]‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one. All these four compounds have shown substantial decrease in the wet dog shake numbers and grade of convulsions with respect to the standard drug diazepam. The most active compound, 7‐[(E)‐{[4‐(dimethylamino)phenyl]methylidene}amino]‐5‐phenyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐one, exhibited 74 % protection against convulsion which was higher than the standard drug diazepam. Furthermore, to identify the binding mode of the interaction amongst the target analogs and binding site of the benzodiazepine receptor, molecular docking study and molecular dynamic simulation were carried out. Additionally, in silico pharmacokinetic and toxicity predictions of target compounds were carried out using AdmetSAR tool. Results of ADMET studies suggest that the pharmacokinetic parameters of all the target compounds were within the acceptable range to become a potential drug candidate as antiepileptic agents.     

Synthesis of 3′-Deoxy-3′ and 5′-Deoxy-5′-[4-(Purin-9-yl/Pyrimidin-1-yl) methyl-1,2,3-Triazol-1-yl]thymidine via 1,3-Dipolar Cycloaddition

Abstract

Synthesis of new 3′-deoxy-3′ and 5′-deoxy-5′-[(4-(purin-9-yl/pyrimidin-1-yl)methyl-1,2,3-Triazol-1-yl]thymidine 8a-g 10a-g from 3′-azido-3′-deoxy-5′-O-monomethoxytrityl-thymidine and 5′-azido-5′deoxythymidine respectively are described. The key step is the 1,3-dipolar cycloaddition between the azido group and N-9/N-1-propargylpurine/pyrimidine derivatives.     

Synthesis of 2-Bromomethyl-3-Hydroxy-2-Hydroxymethyl-Propyl Pyrimidine and Theophylline Nucleosides Under Microwave Irradiation. Evaluation of Their Activity Against Hepatitis B Virus

Alkylation of 2-methylthiopyrimidin-4(1H)-one (1a) and its 5(6)-alkyl derivatives 1b–d as well as theophylline (7) with 2,2-bis(bromomethyl)-1,3-diacetoxypropane (2) under microwave irradia-tion gave the corresponding acyclonucleosides 1-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]-2-methyl-thio pyrmidin-4(1H)-ones 3a–d and 7-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]theophylline (8), which upon further irradiation gave the double-headed acyclonucleosides 1,1 ′-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis[(2-(methylthio)-pyrimidin-4(1H)-ones] 4a–c, and 7,7 ′-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis(theophylline) (9). The deacetylated derivatives were obtained by the action of sodium methoxide. The activity of deacetylated nucleosides against Hepatitis B virus was evaluated. Compound 5b showed moderate inhibition activity against HBV with mild cytotoxicity.     

Fluorescence probe properties of intramolecular charge transfer diphenylbutadienes in micelles and vesicles

This paper reports absorption and fluorescence spectral studies of methyl 4-[(1E,3E)-4-phenylbuta-1,3-dienyl]benzoate (1), N,N-dimethyl-N-[4-[(1E,3E)-4-phenylbuta-1,3-dienyl]phenyl]amine (2), methyl 4-[(1E,3E)-4-[4-(dimethylamino)phenyl]buta-1,3-dienyl]benzoate (3) and 1-methyl-4-[(1E,3E)-4-[4-methoxyphenyl]buta-1,3-dienyl]benzoate (4) in homogeneous media of 1,4-dioxane and 1,4-dioxane-water binary mixtures, and in microheterogeneous media of cetyl trimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and Triton-X-100 micelles, and dipalmotoyl phosphatidylcholine (DPPC) vesicles. The binding site of the diene probes in micelles and vesicles has been determined and it has been found that while in micelles dienes occupy the polar interfacial regions, in vesicles the probes are located deep inside the hydrophobic bilayer. The binding of dienes to the vesicles is stronger than their binding to the micelles as indicated by the binding constant values. The fluorescence emission of the probe dienes in micelles is from a conformationally relaxed intramolecular charge transfer excited state. However, in vesicles, since the excited state conformational motions are restricted due to the rigidity of the alkyl chain, the dienes fluoresce from their planar locally excited states.     

Heterocyclization of 3-deoxy-D-erythro-hexos-2-ulose-1,2-bis(thiosemicarbazone). Crystal structure of the major diastereomer

Both thiosemicarbazone groups of the derivative 1 of 3-deoxy-D-erythro-hexos-2-ulose underwent, on acetylation, a heterocyclization process to give (5R,5'R)-2,2'-diacetamido-4,4'-di-N-acetyl-5'-(1-deoxy-2,3,4-tri-O-acetyl-D-erythritol-1-yl)-5,5'-bis(1,3,4-thiadiazoline) (2) as a major product. The X-ray diffraction data of a single crystal of 2 indicated the R,R configuration for the stereocenters of the thiadiazoline rings (C-5 and C-5'). In the solid state, 2 adopts a sickle conformation (by clockwise rotation of the C-2-C-3 axis of the sugar chain) which has a S//O 1,3-parallel interaction. In solution, as determined by (1)H NMR spectroscopy which included NOE experiments, a similar sickle conformation was observed. From the reaction mixture of acetylation of 1 was isolated the bis(thiadiazoline) 3 as a by-product. The configuration of the C-5 and C-5' stereocenters of 3 were respectively assigned as S,R by comparison of the physical and spectroscopic data of this compound with those of 2.