MASS SPECTROMETERY OF THE ISOMERIC OCTAHYDROBENZOPYRIMIDINE-2′-THIONE-4′,1-SPIROCYCLOHEXANE AND 2′-AMINOOCTAHYDROBENZO-3′,1′-THIAZINE-4′,1-SPIROCYCLOHEXANE

Abstract

Some authors have shown that tetrahydropyrimidine-2-thiones are hydrated in acidic solution and then isomerise to the 2-imino-or 2-enamino-1,3-thiazine.     

Synthesis and antiviral evaluation of 2′,2′,3′,3′-tetrafluoro nucleoside analogs

Herein, we report the synthesis of novel 2′,2′,3′,3′-tetrafluorinated nucleoside analogs along with their phosphoramidate prodrugs. A tetrafluoro ribose moiety was coupled with different Boc/benzoyl-protected nucleobases under Mitsunobu conditions. After deprotection, tetrafluorinated nucleosides 13b, 14b, 20b-22b were reacted with phenyl-(isopropoxy-l-alaninyl)-phosphorochloridate to afford corresponding monophosphate prodrugs 24b–28b. All synthesized compounds were evaluated against several DNA and RNA viruses including HIV, HBV, HCV, Ebola and Zika viruses.     

Pyrylocyanines. 30. Unsymmetrical 4,6,4′,6′-tetraphenyl-substituted 2-pyrido-2-pyrylocyanines with trimethylene groupings in the chromophore

The reaction of methylamine with symmetrical 4,6,4,6-tetraphenyl-substituted 2-pyrylopolycarbocyanines, in which both a positions of the polymethine chain are linked to the positions of the heterocyclic residues by trimethylene groups, was used to synthesize the corresponding pyridopyrylocyanines. The effect of trimethylene groupings in the 2-pyridocyanines on this transformation was examined. The principles involved in the color of the synthesized pyridopyrylocyanines were studied.See [1] for Communication 29.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 345–348, March, 1992.     

Dipyrrolo[1,2-a; 2′,1′-c]pyrazines. 5. Azo coupling of dipyrrolo[1,2-a;2′,1′-c]pyrazines and 5,6-dihydrodipyrrolo[1,2-a; 2′,1′-c]pyrazines

We have synthesized a series of previously unreported azo dyes via the azo coupling of alkyl substituted dipyrrolopyrazines with aryldiazonium chloride. For this type of substrate where one or both -positions of the pyrrole rings of the molecules are not occupied by substituents, electrophilic attack was found to occur initially at carbon atom C₍₃₎.For communication 4 see [1]M. V. Lomonosov State University, Moscow 119899, Russia Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 236–240, February, 1999.     

Dipyrrolo[1,2-a; 2′,1′-c]pyrazines. 4. Aminomethylation of alkyl substituted dipyrrolo[1,2-a; 2′,1′-c]pyrazines and 5,6-dihydrodipyrrolo[1,2-a; 2′,1′-c]pyrazines

We have studied the aminomethylation reaction of alkyl substituted dipyrrolo[1,2-a; 2,1-c]pyrazines and their 5,6-dihydro analogs using different aminomethylating agents. Use of alkoxydialkylaminomethanes (aminoacetals) as Mannich reagents leads to the highest yields of the aminomethylated dipyrrolopyrazines. The compounds prepared have been studied by mass spectrometry.For Communication 3, see [1].M. V. Lomonosov State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 949–957, July, 1998.     

Dipyrrolo[1,2-a; 2′,1′-c]pyrazines. 1. Quantum-chemical study of dipyrrolo[1,2-a; 2′,1′-c]pyrazines in electrophilic substitution reactions

The semiempirical quantum-chemical method PM3 has been used in a study of the electronic and spatial structure of dipyrrolo[l , 2-a; 2,1-cjpyrazines and 5,6-dihydrodipyrrolo[1,2-a; 2,1-cjpyrazines, and also their reactivities in electrophilic substitution reactions (protonation, acylation).M. V. Lomonosov Moscow State University, Moscow 119899 Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1559–1565, November, 1995. Original article submitted September 13, 1995     

An Improved Synthesis of 2′-Hydroxy-3′,4′,6′-trimethoxyacylophenones

A wide variety of 2′-hydroxypolymethoxyacetophenones and propiophenones, e.g. 1a and 1b are used in the synthesis of flavone and ehromone natural products.¹ Repeated attempts to prepare 1a and 1b by reacting 1,2,3,5-tetramethoxybenzene 2 with acetyl or propionyl chlorides and AlCl₃ in ether² gave products which were difficult to purify.³ We traced the problem to ring-ethoxy contaminants which were isolated and tentatively identified as 3a and 3b.     

Synthesis of Steroidal Spiro-1′,2′,4′-triazolidine-3′-thiones

Steroidal ketone thiosemicarbazones (4–6), obtained from the corresponding ketones(1–3), on oxidative cyclization with H₂O₂ at 0°C provide title compounds (7–9), respectively. The structures of these compounds have been established on the basis of their elemental analytical and spectral data.     

Darstellung von 2′,3′-Dideoxy-2′-hydroxymethyl-nucleosiden

Zusammenfassung Die Synthese von geschützten 2,3-Dideoxy-2-hydroxymethyl-nucleosiden wird beschrieben. Die durch ein Mehrstufenverfahren aus Isopropylidenglycerol erhaltenen Nucleoside können als Bausteine zur Darstellung von Oligonucleotiden verwendet werden, deren 2- und 5-Positionen über eine Etherbrücke verbunden sind.

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Synthesis of 2,3-dideoxy-2-hydroxymethyl nucleosides

Summary The synthesis of protected 2,3-dideoxy-2-hydroxymethyl nucleosides is presented. The nucleosides, obtained in a multi-step procedure starting from isopropylideneglycerol, may be used as building blocks for the synthesis of 2,5-ether linked oligonucleotides.

     

Synthesen von Heterocyclen, 29. Mitt.: Über Benzpyrano-(2′,3′∶4,3)-cumarine

Zusammenfassung Benzpyrano-cumarine können aus 3-(2-Hydroxybenzyl)-4-hydroxycumarinen durch Wasserentzug dargestellt werden (Verfahren A). Eine andere Möglichkeit ihrer Synthese besteht im Verschmelzen vonMannich-Basen des 4-Hydroxy-cumarins mit Phenolen bei 180° (Verf. B). Die Umsetzung vonMannich-Basen des Phenols mit 4-Hydroxy-cumarin ist das Gegenstück dazu (Verf. C).     

Synthesis of 2-fluoro-substituted and 2,6-modified purine 2′,3′-dideoxy-2′,3′-difluoro-d-arabinofuranosyl nucleosides from d-xylose

A series of novel purine-modified 2′,3′-dideoxy-2′,3′-difluro-D-arabinonucleosides, including fluorinated analogs of fludarabine and nelarabine, have been prepared via anion glycosylation reactions of salts of 2-fluoropurine derivatives with the glycosyl bromide. A short and efficient synthetic route to the carbohydrate precursor 5-O-benzoyl-2,3-difluoro-α-d-arabinofuranosyl bromide was developed in five steps from d-xylose. Improved synthesis of methyl 5-O-benzoyl-2,3-difluoro-α-d-arabinofuranoside based upon the study of diethylaminosulfur trifluoride (DAST)-reactions with 5-O-protected methyl D-xylosides was explored using mild reaction conditions on the key step. New peculiarities for selective fluorinations of 5-O-benzoylated α- and β-D-pentofuranosides with DAST leading to the formation of mono and difluoro-furanoside derivatives are reported.     

Synthesis and Biological Activity of Novel 2,3-Dihydro-2-phenylsulfonylhydrazono-3-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyl)thiazoles

A series of novel 2,3-dihydro-2-phenylsulfonylhydrazono-3-(2',3',4',6'-tetra-O-acetyl-β-D-glucopyranosyl) thiazoles were designed and synthesized via the reaction of thiosemicarbazide with chloroaldehyde.Their chemical structures were characterized by 1H and 13C NMR spectroscopy and elemental analysis.The bioassay results indicate that some of these compounds exhibit moderate fungicidal and herbicidal activities.     

Structure of Ethanol Coordinated 1,8,15,22-Tetra-（2′,2′,4′-trimethyl-3′-pentoxy）phthalocyaninatocobalt

Crystal structure of ethanol coordinated 1,8,15,22-tetra(2′,2′,4′-trimethyl-3-pentoxy) phthalocyaninatocobalt (C64H80N8O4Co·2C2H5OH, Mr = 1176.43) was determined by X-ray diffrac- tion methods. The crystal is of monoclinic, space group P21/c with a = 16.4294(4), b = 8.0560(2), c = 24.3654(7)(A。), β = 98.3680(8)°, Z = 2, V = 3190.6(1) (A。)3, Dc = 1.225 g/cm3, F(000) = 1262, μ(MoKα) = 0.326 mm-1, the final R = 0.0865 and wR = 0.2737 for 4787 observed reflections with I ≥ 2σ(I). The bulky branched alkyloxy substituents lead to a one structural isomer and space the phthalocyanine molecules where two ethanol molecules coordinate to the cobalt atom from two sides of each molecule.     

Copper(II) complexing with 2′,2′-diethylheptanohydrazide

Acid-base properties of 2′,2′-diethylheptanohydrazide (DEHH) and its complex formation with copper(II) ions in water-isopropanol solutions were studied. Cationic complexes with [Cu²⁺] : [DEHH] ratios of 1 : 1 and 1 : 2 were found to be formed in weak acid media, and an uncharged complex with a [Cu²⁺] : [DEHH] ratio of 1 : 2 was found to be formed in a basic medium. log K _st values were determined. The data obtained were compared with the stability constants of copper(II) 2′,2′-diethylbenzohydrazide complexes.     

COMPLEXES OF MOLYBDENUM(V) AND LANTHANUM(III) WITH 2′,2″′-(2,6-PYRIDINEDIYLDIETHYLIDENE)-DIOXAMOHYDRAZIDE (H2DAPSOX)

Abstract

In a template synthesis from ethanolic solution of MoOCl₃, 2,6-diacetylpyridine (dap), and semioxamazide (sox), in the molar ratio 1:1:2, a dimeric molybdenum(V) complex [Mo₂O₂(H₂dapsox)₂]Cl₆ · 4H₂O (where H₂dapsox = 2′,2″′-(2,6-pyridinediyldiethylidenedioxa-mohydrazide) was obtained. In a similar reaction, starting from La(NO₃)₃ · 6H₂O, the complex [La(H₂dapsox)(NO₃) _x ](NO₃)_3-x · 1/2EtOH (x = 1,2), having coordination number 9, was obtained. In the latter complex two NO₃ Groups were bidentately coordinated in the solid state, but only one in the solution.

Besides [Mo₂O₂(TPP)₂] (TPP = tetraphenylporphyrin), the molybdenum(V) complex [Mo₂O₂ (H₂dapsox)₂]Cl₆ · 4H₂O is the only other known example of a dimeric μ-oxodimolybdenum(V) species that is paramagnetic (μ = 0.95 BM). One of the Mo atoms has pentagonal bipyramidal coordination, and the other pentagonal pyramidal coordination. In aqueous solution a rare example of a pentagonal pyramidal ion [MoO(dapsox)]⁺ is presumably present. Solution EPR spectra (at 77K) cannot be related to either of the two known types of Mo(V) species based on the extent of g anisotropy. The substances also were characterized by IR and electronic spectroscopy, and by thermal analysis.     

Synthesis of 2′,3′-Dideoxy-2′-Fluorokanamycin A

2′,3′-Dideoxy-2′-fluorokanamycin A (23) was prepared by condensation of 6-azido-4-0-benzoyl-2,3,6-trideoxy-2-fluoro-α-D-ribo-hexopyranosyl bromide (13) and a protected disaccharide (19). Methyl 4,6-0-benzylidene-3-deoxy-β-D-arabino-hexopyranoside (5) prepared from methyl 4,6-0-benzylidene-3-chloro-3-deoxy-β-D-allo-hexopyranoside (1) by oxidation with pyridinium chlorochromate followed by reduction with Na₂ S₂O₄ was fluorinated with the DAST reagent to give methyl 4,6-O-benzylidene-2,3-dideoxy-2-fluoro-β-D-ribo-hexopyranoside (7). Successive treatment of 7 with NBS, NaN₃ and SOBr₂ gave 13. The structure of the final product (23) was determined by the ¹H and ¹⁹F and shift-correlated 2D NMR spectra.     

AROMATIC AND HETEROCYCLIC DINITRILES AND THEIR POLYMERS ⅩⅢ. POLYMERIZATION KINETICS OF BENZONITRILE AND THE STRUCTURE OF PRODUCTS

The polymerization kinetics of benzonitrile were studied, and the formation rate constants of s-triazine structure and linear polymer were determined. The influence of polymerization temperature and the amount of zinc chloride as catalyst on the ratio of linear to cyclic structure were also investigated, and the obtained results were discussed.     

N.M.R.DETERMINATION OF THE STRUCTURE AND CONFORMATION OF BIOLOGICAL MOLECULES

IntroductionN.M.R.is known to be useful forstructure determination of natural products,but it's main advantage compared with otherphysical techniques like crystallography is