Simple synthesis of 6-alkyl-5H-benzo[a]phenoxazin-5-ones

6-Alkyl-5H-benzo[a]phenoxazin-5-ones were prepared by the reaction of 5H-benzo[a]phenoxazin-5-one with carboxylic acid in the presence of silver ion and peroxydisulfate.

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Eine einfache Synthese von 6-Alkyl-5H-benzo[a]phenoxazin-5-onen (Kurze Mitteilung)

Zusammenfassung 6-Alkyl-5H-benzo[a]phenoxazin-5-one wurden mittels Reaktion von 5H-Benzo[a]phenoxazin-5-onen mit Carbonsäuren in Gegenwart von Silberionen und Peroxydisulfat dargestellt.

     

Density functional theory analysis of some triple-decker sandwich complexes of iron containing cyclo-P5 and cyclo-As5 ligands

Structure and bonding in triple-decker cationic complexes [(η⁵-Cp)Fe(μ,η:η⁵-E₅) Fe(η⁵-Cp)]⁺ (1: E = CH, 2: E = P, 3: E = As) and [(η⁵-Cp)Fe(μ,η:η⁵-Cp)Fe(η⁵-E₅)]⁺ (E = P, As) are examined by density functional theory (DFT) calculations at the B3LYP/6-31+G* level. These species exhibit the lowest energy when all the three ligands are eclipsed. In the complexes with bifacially coordinated cyclo-E₅, the perfectly eclipsed D_5h sandwich structure a is found to be a potential minimum. The energy difference between the fully eclipsed and the staggered conformations b and c are within 1.0, 2.1, and 6.3 kcal/mol, respectively, for E = CH, P, and As. The isomeric species with monofacially coordinated cyclo-E₅ (E =P, As), [(η⁵ -Cp)Fe(μ,η :η⁵-Cp)Fe(η⁵-E₅)]⁺ are predicted to be about 30 and 60 kcal/mol higher in energy , respectively, for E = P and As. The calculations predict that the bifacially coordinated cyclo-E₅ (E =P, As) undergoes significant ring expansion leading to ``loosening of bonds' as observed experimentally. The consequent loss of aromaticity in the central cyclo-E₅ indicates that significant π-electron density from the ring can be directed towards bonding with the iron centers on both sides. The diffuse nature of the π-orbitals of cyclo-P₅ and cyclo-As₅ can lead to better overlap with the iron d-orbitals and result in stronger bonding. This is reflected in the bond order values of 0.377 and 0.372 for the Fe-P and Fe-As bonds in 2a and 3a, respectively. The natural population analysis reveals that the Fe atom that is coordinated to a cyclo-E₅ (E = P, As) possesses a negative charge of −0.23 to −0.38 units due to transfer of electron density from the inorganic ring to the metal center.     

Concerning the “synthesis of 2-amino-5-aryl-5H-thiazolo[4,3-b]-1,3,4-thiadiazoles”

Compounds described previously as 2-amino-5-aryl-5H-thiazolo[4,3-b]-1,3,4-thiadiazoles were found to be thiosemicarbazones of aromatic aldehydes. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya No. 6, pp. 1228–1229, June, 1997.     

Synthesis and properties of 5-diazoimidazoles and imidazolyl-5-diazonium salts

Diazotization of 4-R-5-aminoimidazoles (R = CONHAr, CONHAlk, morpholinocarbonyl, or piperidinocarbonyl) with sodium nitrite in aqueous solutions of mineral acids afforded the corresponding 5-diazoimidazoles, whereas the reactions in concentrated tetrafluoroboric acid produced imidazolyl-5-diazonium salts. In the solid phase, diazonium salts are transformed into the corresponding diazo compounds.     

Regio- and stereoselective 1,3-dipolar cycloaddition of arylnitrile oxides to 5-acetoxy-2(5H)-furanone

Summary Arylnitrile oxides undergo regio- and stereo-specific 1,3-dipolar cycloaddition reactions with 5-acetoxy-2(5H)-furanone. In each case a single product3a–3g results from ananti approach to the 5-acetoxy substituent, the oxygen of the 1,3-dipole being attached to C-4 of furan. Under similar conditions 5-benzoyloxy-2(5H)-furanone yields3h–3i. The structures of the adducts were determined by¹H- and¹³C-NMR spectroscopy.

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Regio- und stereoselektive 1,3-dipolare Cycloaddition von Arylnitriloxiden mit 5-Acetoxy-2(5H)-furanon

Zusammenfassung Arylnitriloxide reagieren mit 5-Acetoxy-2(5H)-furanon in einer regio- und stereoselektiven 1,3-dipolaren Cycloaddition. In jedem der untersuchten Fälle ergaben sich die einheitlichen Produkte3a–3g als Folge eineranti-Annäherung an den 5-Acetoxysubstituenten, wobei der Sauerstoff des 1,3-Dipols an das C-4 des Furans addiert. Unter ähnlichen Bedingungen ergab 5-Benzoyloxy-2(5H)-furanon die Produkte3h–3i. Die Strukturen der Addukte wurden mittels¹H-und¹³C-NMR bestimmt.

     

Efficient methods for the synthesis of pyrido[2,3-d]pyrimidin-5-ones from 4-amino-5-acetylpyrimidines

New methods for annelation of a pyridine ring to a pyrimidine ring were suggested. Substituted 8H-pyrido[2,3-d]pyrimidin-5-ones (8a-f) were synthesized by the interaction of 2,6-disubstituted 4-amino-5-acetylpyrimidines (1–4) with formamide or acetamide acetals followed by cyclization under the action of sodium methoxide in methanol. 2,4-Disubstituted 7-phenyl-8H-pyrido[2,3-d]pyrimidin-5-ones (11a-c) were prepared by the reaction of 2,6-disubstituted 5-acetyl-4-benzoylaminopyrimidines (10a-c) with MeONa in boiling BuOH.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1469–1474, August, 1994.     

Syntheses based on 2-ethoxycarbonylmethyl-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-5(5H)-one

2-Ethoxycarbonylmethyl-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-5(5H)-one containing the active methylene group reacts easily with carbon disulfide and phenyl isothiocyanate in the presence of sodium hydride. Further alkylation of the reaction product by alkyl halides results in the formation of the corresponding 1,3,4-thiadiazolo[3,2-a]pyrimidine derivatives containing a ketene dithioacetal fragment. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2371–2373, November, 1998.     

The reaction of 2-amino-7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]-pyrimidine with carbon disulfide and alkylation of its products

In the reaction with carbon disulfide, 2-amino-7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine (1) forms the alkaline salts of substituted dithiocarbamic or iminodithiocarbonic acids depending on the molar ratio between1, CS₂, and the alkali. The alkylation of these salts leads to the esters ofN-(7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine-2-yl)dithiocarbamic (2) and diesters of (7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine-2-yl)iminodithiocarbonic acids (3). The synthesis of asymmetric diesters3 may be fulfilled based on monoesters2.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 14–14, August, 1994.     

Spectrofluorimetric determination of traces of indium with 5-chiorosalicylidene-o-aminophenol

A Spectrofluorimetric method for microdetermination of indium, based on the formation of a fluorescent 21 (ligand:metal) complex between In (III) and 5-chlorosalicylidene-o-aminophenol at an apparent pH of 4.70 in an aqueous-ethanol medium (50% v/v ethanol) is proposed. The calibration graph is linear over the range 10.0–80.0 g/l, the relative standard deviation 2.7% and the detection limit 1.5 g/l. The method has been applied to the determination of indium in synthetic samples and natural waters.     

Room-temperature interaction of n-hexane with ZSM-5 zeolites

In this work, room temperature interaction of n-hexane with HZSM-5 (Si/Al=20) and ion-exchanged samples containing one (CuZSM-5, FeZSM-5 and MnZSM-5) or two transition-metal cations (Fe,CuZSM-5; Cu,MnZSM-5 and Fe,MnZSM-5) was studied by microcalorimetry and TPD methods. Both differential heats and the amounts of n-hexane adsorbed per one unit cell were quantitatively determined. Higher heats of adsorption and higher amounts of adsorbed gas were found for ion-exchanged samples than for HZSM-5. The experiments of n-hexane adsorption on hydrated samples were also performed. The amounts of n-hexane adsorbed on hydrated ZSM-5 were lower in comparison with dehydrated samples, while the energies of interaction were similar.     

Aromatization ofn-butane over Ni-ZSM-5 and Cu-ZSM-5 zeolite catalysts prepared by using Ni and Cu impregnated silica, fiber

The reaction ofn-butane aromatization was carried out over Ni-ZSM-5 and Cu-ZSM-5 zeolite catalysts prepared by using Ni and Cu impregnated silica fiber during the process of ZSM-5 zeolite synthesis. The catalysts prepared were characterized by X-ray powder diffraction, nitrogen adsorption and X-ray fluorescency. The acidic properties of the catalysts were investigated by temperature-programmed desorption of ammonia using a mass spectrometer equipped with a QTMD detector. The effect of catalyst pretreatment, reaction temperature, and time on stream on the reaction ofn-butane to aromatic hydrocarbons were investigated. The modification of ZSM-5 by Ni and Cu increased the selectivity to aromatic hydrocarbons. The state of Ni and Cu and their stabilization in the ZSM-5 structure was highly influenced by the mode of catalyst pretreatments.     

4-Phosphoranylidene-5(4H)-oxazolones — A novel synthesis and properties

Summary 4-Phosphoranylidene-5(4H)-oxazolones (2), a hardly known class of phosphorus ylides, were readily prepared from 4-unsubstituted-5-(4H)-oxazolones (1) by treatment with Ph₃P-Br₂, Bu₃P-Br₂, Ph₃P-CCl₄, or Ph₃P-CBr₄ adducts in the presence of triethylamine in CH₂Cl₂ at room temperature in a novel, efficient one-pot procedure. The spectroscopic properties of the ylides are reported and discussed.

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4-Phosphoranyliden-5(4H)-oxazolone — Eine neue Synthese und Eigenschaften

Zusammenfassung 4-Phosphoranyliden-5(4H)-oxazolone, eine sehr wenig bekannte Gruppe der Phosphor-ylide, wurden auf einfache Weise nach einem neuen Eintopfverfahren mit guten Ausbeuten hergestellt. Als Ausgangsverbindungen wurden 4-unsubtituierte-5-(4H)-Oxazolone (1) eingesetzt, die unter der Einwirkung von Addukten wie Ph₃P-Br₂, Bu₃P-Br₂, Ph₃P-CCl₄ oder Ph₃P-CBr₄ in Anwesenheit von Triethylamin in CH₂Cl₂ bei Zimmertemperatur die Titelverbindungen liefern. Die spektroskopischen Eigenschaften der Ylide werden berichtet und diskutiert.

     

Fragmentation of 1-hydroxy-2-(5H-dibenzo[a,d]cyclohepten-5-yl)-1-phenylethyl cation in superacid

The 1-hydroxy-2-(5H-dibenzo[a,d]cyclohepten-5-yl)-1-phenylethyl cation generated under long life conditions undergoes fragmentation to afford 5H-dibenzo[a,d]cycloheptenyl-and methylphenylhydroxycarbinyl canons but does not undergo carbocationic cyclization.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 397–399, February, 1996.     

Some transformations of 2-chloromethyl-7-methyl-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one

The reactions of 2-chloromethyl-7-methyl-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one withtert-butyl hypochlorite and molecular bromine and the replacement of the chlorine atom in the chloromethyl group through the action of piperidine and morpholine were investigated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 908–910, May, 1994.     

Pyridazines with heteroatom substituents in position 3 and 5, part 1: 5-Hydroxy-3(2H)-pyridazinone and its derivatives

Summary The synthesis of the title compound7 was achieved starting with mucochloric acidvia the pyridazinones1,2 and6. The electrolytic ionisation constants for7 were found to be 4.81 (±0.03) and –0.3 (±0.3). Crystal structure analyses were performed for7 and its fixed derivatives6 and9.Dedicated to Prof. Dr. Hans Junek on the occasion of his 60th birthday     

Synthesis,properties, and structures of 5-nitroalkyl-5H-(1,2,3)triazolo[4,5-c]furazans

Methods for the synthesis of the first representatives of 5-nitroalkyl-5H-(1,2,3)triazolo[4,5c]furazans have been developed, and some of their properties have been studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1315–1317, July, 1995.     

Synthesis of 5H-thiazolo[3,2-a]pyrimidine derivatives from 6-methyl-2-thiouracil and 1-acyl-2-bromoacetylenes. X-ray structural study of 3-benzoyl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one

3-Acyl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-ones were synthesized by the reaction of 1-acyl-2-bromoacetylenes with 6-methyl-2-thiouracil, carried out with heating in DMF, dioxane, or acetonitrile in the presence of triethylamine. The structure of 3-benzoyl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one was established by X-ray structural analysis.Deceased in 1995.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2306–2308, September, 1996.     

微波辐射下5-取代-2-硫代海因衍生物的合成

微波辐射下, 由硫氰酸铵与α-氨基酸通过两步反应合成了11种5-取代-2-硫代海因衍生物, 并用¹H NMR, IR和元素分析确证了中间产物和终产物的结构. 对比常规加热方法, 微波辐射具有反应时间短(4 min), 每步反应产率高(85%～93%)的优点. 同时对合成化合物2h的反应历程进行了讨论.     

One-pot synthesis of 2-amino- 5-aryl -5H-thiazolo[4,3-b]-1,3,4-thiadiazoles

Equimolar mixtures of aromatic aldehydes with thioglycolic acid and thiosemicarbazide in H₂SO₄ transform into 2-amino-5-aryl-5H-thiazolo[4,3-b]-1,3,4-thiadiazoles.Translated fromIzvestiya Akademioi Nauk. Seriya Khimicheskaya, No. 3, pp. 763–764, March, 1996.     

老鼠Tet1蛋白能氧化单链脱氧核糖核酸上的5-甲基胞嘧啶到5-羟甲基胞嘧啶和5-羧基胞嘧啶(英文)

5-甲基胞嘧啶在哺乳动物细胞中具有广泛的作用.而它被双脱氧家族Tet蛋白氧化所得的产物5-羟甲基胞嘧啶、5-醛基胞嘧啶和5-羧基胞嘧啶也被证明在细胞发育和5-甲基胞嘧啶动态平衡调控中具有关键的作用.已有的研究结果表明,Tet蛋白能够识别双链DNA上的5-甲基胞嘧啶,并将其氧化成5-羟甲基胞嘧啶、5-醛基胞嘧啶和5-羧基胞嘧啶.我们通过质谱仪检测发现,老鼠Tet1蛋白的DNA结合结构域还能识别和氧化单链DNA上的5-甲基胞嘧啶.这一发现暗示我们,Tet蛋白家族不但具有已经发现的氧化双链DNA上5-甲基胞嘧啶的功能,还有可能作用于DNA的复制及转录,甚至具有氧化单链RNA上对应的甲基修饰碱基的能力.