Synthesis of 2′-hydroxychalcones and related compounds in interfacial solid-liquid conditions

A general synthetic method of 2′-hydroxychalcones and 2′-hydroxyphenyl-(2-alkylvynyl) ketones in interfacial solid-liquid conditions, is described. No secondary reactions were observed. The interfacial mechanism is discussed by means of the structure of active sites of solid.     

Synthesis and bioactivity of N-cyclopropanecarboxyl-N′-pyridin-2-yl thiourea derivatives and related fused ring compounds

Cyclopropanecarboxylic acid or 2,2-dimethyl cyclopropanecarboxylic acid was used as a leading compound for its biological activity.Six new N-(substituted) cyclopropanecarboxyl-N′-pyridin-2-yl thioureas were prepared.Compound 5 was obtained by oxidizing cyclization of compound 4 in the presence of bromine in chloroform solution.The structures of 4 and 5 were confirmed by ~1H NMR and elemental analysis.The preliminary biological tests indicate that compound 4b and 4e have excellent herbicidal activity,and ...     

Synthesis of 5-Aryluridines and 5-Aryl-2′-deoxyuridines

The palladium-catalysed coupling of both 5-iodouridine and 5-iodo-2′-deoxyuridine derivatives with functionalized and non-functionalized arylboronic acids and aryltrimethylstannanes gave moderate to good yields of the corresponding 5-aryluridines and 5-aryl-2′-deoxyuridines.     

Electrochemical and enzymatic study of 2-chloro-2′-deoxyadenosine (antileukemic agent) and related compounds

The electrochemical reduction of two 2-halogeno derivatives of 2′-deoxyadenosine, antileukemic agents (2-chloro-2′-deoxyadenosine (2-CldAdo) and 2-bromo-2t'-deoxyadenosine (2-BrdAdo)) and related ribosides (7-methyladenosine (m⁷Ado) and purine riboside (PR)) have been examined by d.c. and a.c. polarography as well as by macroelectrolysis.2-CldAdo (Cladribine, Leustatin) undergoes a one-step reduction in very acidic medium, pH 1–3, while the reduction of 2-BrdAdo occurs in two steps in the pH range 1–6. Both 2-halogeno adenosines involve reduction of the C-halogen bond and the pyrimidine ring. The reduction products have been examined by UV and nuclear magnetic resonance spectroscopy and high performance liquid chromatography analysis and the reduction mechanism has been formulated. All investigated compounds including PR and m⁷Ado exhibit high surface activity confirmed by a.c. polarography.All investigated compounds and theirs reduction products were tested for inhibitory activity vs. Escherichia coli PNP with inosine as substrate and inhibition constants have been determined. 2-CldAdo and 2-BrdAdo, as well as the reduction products of 2-CldAdo and PR, were found to be good inhibitors of E. coli PNP, whereas the reduction products of m⁷Ado and 2′-deoxyadenosine do not bind to the enzyme.     

Synthesis of liquid-crystalline 4,4′-dodecyloxybenzoyloxybenzoyl-4-oxy-2-hydroxybenzaldehyde and related azomethine

4,4′-Dodecyloxybenzoyloxybenzoyl-4-hydroxy-2-hydroxybenzaldehyde and the related linear azomethine, the intermediates at the formation of iron(III)-containing complexes, were synthesized. These compounds were characterized by thin layer chromatography, elemental analysis, IR, NMR spectroscopy, mass spectrometry, and by the data of differential scanning calorimetry. The aldehyde and the azomethine show mesomorphic properties.     

Synthesis of 2′-5′,3′-5′ linked triadenylates

2′-5′,3′-5′ Linked triadenylates have been synthesized by direct bisadenylylation of adenosine 2′ and 3′ hydroxyls with an adenosine 5′-phosphorochloridite followed by oxidation.     

Synthesis of Isomeric Δ2-Pyrazolines From 2′-Hydroxy-5′-chlorochalcones and its Derivatives

Suitably substituted 2′-hydroxy-5′-chlorochalcones with hydrazine hydrochloride in refluxing DMF afforded isomeric Δ²-pyrazolines, which were characterized on the basis of chemical and spectral data.     

Synthesis of 5-Alkenyl-2′-Deoxyuridines Via Organostannanes

The palladium-catalysed coupling of 3,5 Di-O-p-toluoyl-5-iodo-2′ -deoxyuridine with functionalized and non-functionalized alkenylstannanes gave moderate to good yields of the corresponding 5-alkenyl-2 -deoxyuridines.     

Synthesis and Crystal Structure Analysis of 5′-O-Tosyl-2,3′-anhydrothymidine

In this paper=5′-O-tosyl-2,3′-anhydrothymidine has been synthesized and its crystal structure was analyzed. The crystal belongs to the triclinic system=space group P1=with a=5.397(2)=b=6.1886(18)=c=3.507(5) =α =87.74(2)=β =89.84(4)=γ =73.79(2)°=C17H18N2O6S=Mr=378.39=Z=1=V=432.8(3)3=Dc=1.452 g/cm3=F(000)=198 and Flack =-0.11(14). No intermolecular hydrogen bonds exist in the crystal=and the angle between benzene ring and pyrimidine planes is 32.23°.     

Synthesis of Isonucleoside 5′-Triphosphates

Abstract

A series of isonucleoside 5′-triphosphates were synthesized via a rapid and efficient method. The structures of the triphosphates (8a–8d) were characterized by ³¹P NMR and TOF-MS.     

Synthesis and properties of trifluoromethylating steroid compounds

Trifluoromethyl steroids la,b; 2a,b; 3a,b have been synthesized by starting from estren 3,17-dicarbonyl-3,3-dimethyl ether (4) and dl-18-methyl-2(3)l5(10)-estra-diene-17-carbonyl-3-methyl ether (5),and by using trimthyltrifluoromethylsilane as the trifluoromethylating agent under the catalysis of tetrarnethylam-monium fluoride.The overall yields were 82%,76%; 54%,62%; and 27%,25%,respectively The α-configura tion of trifluoromethyl group of 17-position was determined by X-ray crystal diffraction method Compounds 1a,2a and 3a showed high affinity for rat uterus PRc.The test of biological activities of compounds 1b,2b and 3b is proceeding.     

Excited state intramolecular hydrogen atom transfer of phenylethynyl-substituted 2′-hydroxychalcones

(E)-1-[2-Hydroxy-4-(phenylethynyl)phenyl]-3-[4-(phenylethynyl)phenyl]prop-2-en-1-one (1), (E)-1-[2-hydroxy-4-(phenylethynyl)phenyl]-3-phenylprop-2-en-1-one (2), and (E)-1-(2-hydroxyphenyl)-3-[4-(phenylethynyl)phenyl]prop-2-en-1-one (3), which belong to a new class of 2′-hydroxychalcones with phenylethynyl group(s) at the para position of the phenyl ring, were synthesized, and their photochemical properties were investigated. The lowest energy absorption band of 1 peaks at a longer wavelength (383 nm) with a much larger molar extinction coefficient (5.0 × 10⁴ M ^?1 cm^?1) than that of the parent 2′-hydroxychalcone (2′HC) (2.0 × 10⁴ M ^?1 cm^?1 at 318 nm). Upon photoexcitation, all three compounds underwent excited-state intramolecular hydrogen atom transfer (ESIHT) to produce an excited tautomer that emitted fluorescence with a large Stokes shift in the longer wavelength region at 600–700 nm. The quantum yield of the tautomer fluorescence of 1 was not high at 298 K (Φ _f = 9.1 × 10^?5), but was highest among 2′HC and its analogues. The Φ _f values of 1–3 increased 10–30 fold upon reducing the temperature from 298 to 77 K.     

Synthesis and Crystal Structure of 5-N-i-Propyl-2-(2′-nitrobenzenesulfonyl)-glutamine

IntroductionAcetohydroxy acid synthase(AHAS) is a perfecttarget for the design of environmentally benign herbi-cides because it is a key enzyme that is absent in ani-mals but is important for the biosynthesis of branched-chain amino acids in plants[1,2]. …     

Synthesis of 2′,3′-dideoxynucleosides from 5-alkoxymethyluracils

Summary A modified synthesis of protected 2,3-dideoxyribose5 starting fromL-glutamic acid (1) is described. Reaction of5 with silylated 5-hydroxymethyluracil7 a and 5-alkoxymethyluracils7 b–e in the presence of trimethylsilyl triflate afforded an anomeric mixture of 2,3-dideoxyuridine derivatives8 a–e and9 a–e. Deprotection with methanolic ammonia and separation by chromatography gave the corresponding nucleosides10 a–e and11 a–e. Treatment of9 b–e with tri(1H-1,2,4-triazol-1-yl)phosphine oxide and subsequent reaction of12 b–e with ammonia in dioxane afforded the cytosine derivatives13 b–e which on treatment with methanolic ammonia gave the corresponding 2,3-dideoxycytidine derivatives14 b–e and15 b–e. In contrast with the parent compounds, these alkoxymethyl derivatives had no appreciable activity against human immunodeficiency virus (HIV-1).

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Synthese von 2,3-Dideoxynucleosiden aus 5-Alkoxymethyluracilen

Zusammenfassung Ausgehend vonL-Glutaminsäure (1) wird eine modifizierte Synthese von geschützter 2,3-Dideoxyribose (5) beschrieben. Reaktion von5 mit silyliertem 5-Alkoxymethyluracilen7 b–e in Gegenwart von Trimethylsilyltriflat ergab anomere Mischungen der 2,3-Dideoxyuridinderivate8 a–e und9 a–e. Abspaltung der Schutzgruppe mit methanolischen Ammoniak und chromatographische Trennung ergab die entsprechenden Nucleoside10 a–e und11 a–e. Behandlung von9 b–e mit Tri(1H-1,2,4-triazol-1-yl)phosphinoxid und nachfolgende Reaktion von12 b–e mit Ammoniak in Dioxan ergab die Cytosinderivate13 b–e, welche nach Behandlung mit methanolischem Ammoniak die entsprechenden 2,3-Dideoxycytidinderivate14 b–e und15 b–e ergaben. Im Gegensatz zur Stammverbindung hatten diese Alkoxymethylderivate keine nennenswerte Wirksamkeit gegen den menschlichen Immunschwächevirus (HIV-1).

     

Synthesis of azafluorenones and related compounds using deprotocupration–aroylation followed by intramolecular direct arylation

The efficiency of the deprotocupration–aroylation of 2-chloropyridine using lithiocuprates prepared from CuX (X=Cl, Br) and LiTMP (TMP=2,2,6,6-tetramethylpiperidido, 2 equiv) was investigated. CuCl was identified as a more suitable copper source than CuBr for this purpose. Different diaryl ketones bearing a halogen at the 2 position of one of the aryl groups were synthesized in this way from azines and thiophenes. These were then involved in palladium-catalyzed ring closure: substrates underwent expected CH-activation-type arylation to afford fluorenone-type compounds, and were also subjected to cyclization reactions leading to xanthones, notably in the presence of oxygen-containing substituents or reagents.     

Synthesis and evaluation of antiviral activity of 2′-deoxyuridines with 5-methylene-2-thiohydantoin substituents in the 5-position

Summary 1-(2-Deoxy-3,5-bis-O-(4-methylbenzoyl)-D-erythro-pentofuranosyl)-5-formyluracil (4) was synthesized from 5-formyluracil and an appropriate methyl glycoside and condensed with 2-thiohydantoin (5a) and its corresponding 3-phenyl derivative5b to give 5-[1-(2-deoxy-3,5-bis-O-(4-methylbenzoyl)-D-erythro-pentofuranosyl)uracil-5-ylmethylene]-2-thiohydantoins7a and7b, respectively, in 65–70% yield. They were deprotected with sodium methoxide in methanol to give both anomers of the free nucleosides. In a different route 5-formyluracil (1) was condensed with5b and subsequently with an appropriate methyl glycoside to give7b.On leave from Chemistry Department, Faculties of Science and Education, Tanta University, Tanta, Egypt