Synthesis of 2-(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-carbonyl)-6,6-dimethyl-3-phenyl-3,5,6,7-tetrahydro-2H-benzofuran-4-one Derivatives via Multicomponent Reaction

A sequential one-pot, two-step reaction for an efficient preparation of 2-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-carbonyl)-6,6-dimethyl-3-phenyl-3,5,6,7-tetrahydro-2H-benzofuran-4-one derivatives has been described. One-pot reaction of in situ–formed benzopyran-substituted pyridinium ylides with aromatic aldehydes and dimedone gives corresponding 2,3-dihydrofurans in good yields. The structures of all the newly synthesized compounds were confirmed from their analytical and spectral data.     

Dehydration of 4-hydroxy-4-methyl-3-phenylamino-oxazolidin-2-ones

The dehydration of two 5,5-disubstituted 4-hydroxy-4-methyl-3-phenylaminooxazolidin-2-ones into the corresponding 4-methylene-3-phenylaminooxazolidin-2-ones has been carried out. The structure of the products was confirmed by X-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1512–1517, October, 2004.     

芳亚甲基丙二腈和4-羟基喹啉-2-酮反应的研究

以芳亚甲基丙二腈和4-羟基喹啉-2-酮为原料,在六氢吡啶催化下以乙醇为溶剂,80℃合成了一系列新的2-氨基-3-氰基-4-芳基5,6-二氢化-4H-吡喃并[3,2-c]喹啉-5-酮衍生物,反应条件温和,产率较高,并通过单晶X射线衍射分析确证产物的结构.     

Synthesis of 2,5 -Bis(4-methyl-2-thienyl)thiophene and 2,5-Bis(4-methyl-2-thienyl)pyrrole

Syntheses of 2,5-bis(4-methyl-2-thienyl)thiophene 3 and 2,5-bis(4-methyl-2-thienyl)pyrrole 4 are described. The key step involves Stetter reaction between 4-methyl-2-thiophenecarboxaldehyde and divinyl sulfone. Cyclizaton of the resulting 1,4-bis-(4-methyl-2-thienyl)-1,4-butanedione 2 with Lawesson's reagent gives 2,5-bis(4-methyl-2-thienyl)thiophene 3, whereas condensation with ammonium acetate provides the 2,5-bis(4-methyl-2-thienyl)pyrrole 4.     

离子液体中脂肪酶催化拆分外消旋烯丙酮醇反应

 以离子液体为溶剂,考察了溶剂类型、水活度、温度、 pH值和共溶剂等因素对脂肪酶催化拆分外消旋烯丙酮醇(R,S)-4-羟基-3-甲基-2-(2-丙烯基)-2-环戊烯-1-酮反应的影响,并与常用于外消旋烯丙酮醇拆分的有机溶剂乙酸乙烯酯进行了比较. 结果表明,在离子液体［bmim］PF6中脂肪酶的催化性能较好,酶初始反应速率为18.48 μmol/(g·min), 半衰期为74.53 h, 高于在乙酸乙烯酯中的相应值(9.18 μmol/(g·min)和64.29 h). 但离子液体中拆分反应的转化率低于在乙酸乙烯酯中的转化率,可以通过向离子液体中补加酰基供体来提高外消旋烯丙酮醇的转化率. 两种反应介质中最佳酶反应条件均为水活度0.17, 温度40 ℃和pH=7, 但加入共溶剂后,离子液体中脂肪酶催化拆分外消旋烯丙酮醇的效率降低,而在乙酸乙烯酯中则有所提高.     

Synthesis of 5-[2-(Phenoxy)ethyl] Derivatives of 6-Methyluracil, 6-Methyl-2-thioxo-2,3-dihydro-1H-pyrimidin-4-one,and 2-Imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one

A synthesis of novel derivatives of 6-methyluracil, 6-methyl-2-thioxo-, and 2-imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one containing a 2-(phenoxy)ethyl substituent at position 5 of the pyrimidine ring has been carried out. It was found that 5-[2-(phenoxy)ethyl] derivatives of 6-methyl-2-thioxo- and 2-imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one are obtained by the condensation of the corresponding ethyl 3-oxo-2-(2-phenoxyethyl)butanoates with thiourea or guanidine. 6-Methyl-5-[2-(phenoxy)ethyl]uracils can be prepared by treating 6-methyl-5-[2-(phenoxy)ethyl]-2-thioxo-2,3-dihydro-1H-pyrimidin-4-ones with an excess of aqueous monochloroacetic acid solution. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1213–1217, August, 2005.     

Tributylphosphine Catalyzed O -Vinylation of 3-Hydroxy-2-methyl-4 H -pyran-4-one

Protonation of the highly reactive 1:1 intermediates produced in the reaction between tributylphosphine and dimethyl acetylenedicarboxylate by 3-hydroxy-2-methyl-4 H -pyran-4-one leads to vinyltributylphosphonium salts, which undergo an addition-elimination reaction in CH 2 Cl 2 at room temperature to produce dimethyl 2-[(2-methyl-4-oxo-4 H -pyran-3-yl)oxy]-2-butenedioate (1:1 mixtures of E and Z isomers) in fairly good yields.     

Reaction of 4-methyl-4-tribromomethylcyclohexa-2,5-dien-1-one with zinc metal

4-Methyl-4-tribromomethylcyclohexa-2,5-dien-1-one reacts with zinc dust in absolute DMF to give a mixture of 4-bromo-5-methylcyclohepta-2,4,6-trien-1-one, 4-methyl-cyclohepta-2,4,6-trien-1-one, and 4-dibromomethyl-4-methylcyclohexa-2,5-dien-1-one. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 177–178, January, 1998.     

Studies on the esterifications of 9-（hydroxyimino）-4-methyl-8,9-dihydrofuro[2,3-h]chromen-2-one with acid chlorides under different conditions

The esterifications of 9-（hydroxyimino）-4-methyl-8,9-dihydrofuro[2,3-h]chromen-2-one （4） with acid chlorides afforded normal oxime-esters 3a-e in 35-78% yields in presence of excessive 4-dimethylaminopyridine as the acid scavenger, whereas the reactions gave unexpected 8-substituted products N-（8-chloro-4-methyl-2-oxo-2H-furo-[2,3-h]chromen-9-yl）amides （5a-c） and 4-methyl-2,9-dioxo-8,9-dihydro-2H-furo[2,3-h]chromen-8-ylcarboxyloates （6d-e） by using excessive acid chlorides. The structures of 10 new compounds were determined by 1H NMR, 13C NMR, MS and HRMS, and the possible mechanism for the formation of unexpected products 5a--c and 6d-e was also proposed.     

The Use of 4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one as “Masked” α-Bromo-α'-Hydroxy Ketone in the Synthesis of Heterocyclic Systems

4-(Bromomethylene)-5,5-dimethyl-1,3-dioxolan-2-one was obtained on the basis of the readily obtainable 4-methylene-5,5-dimethyl-1,3-dioxolan-2-one. It forms 2-imidazo[1,2-a]pyridin-2-yl-2-propanol with 2-aminopyridine, 11a-hydroxy-1,1-dimethyl-3-oxo-1,5,11,11a-tetrahydro[1,3]oxazolo[3,4-a]pyrido[1,2-d]-10-pyrazinium bromide with 2-(aminomethyl)pyridine, and the corresponding derivative of 4-hydroxyoxazolidin-2-one with 2-(3,4-dimethoxyphenyl)ethylamine. The last product was converted by intramolecular amidoalkylation without isolation into 10b-(bromomethyl)-8,9-dimethoxy-1,1-dimethyl-1,5,6,10b-tetrahydro[1,3]oxazolo[3,4-a]isoquinolin-3-one.     

Regio- and stereochemical features of the reactions of 1,2,5-trimethylpiperidin-4-one with chalcone

The reactions of N-substituted piperidin-4-ones with benzylideneacetophenone, resulting in the synthesis of a number of heterocyclic 1,5-dicarbonyl compounds, were studied. 1,2,5-Trimethylpiperidin-4-one enters into cascade-type chalcone addition accompanied by intramolecular aldol condensation giving rise to the 3-azabicyclo[3.3.1]nonane system. The conformations of the 1,5-dicarbonyl compounds and azabicyclononanes synthesized were determined; the regio- and stereochemical features of the reactions of 1,2,5-trimethylpiperidin-4-one with chalcone were studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2693–2697, December, 2004.     

7—[（4—甲基2—胂酸基苯）偶氮]—8—羟基喹啉—5—磺酸荧光光度法测定氟

本文介绍了７－［（４－甲基－２－胂酸基苯）偶氮］－８－羟基喹啉－５－磺酸的合成方法以及性能，详细研究了氟对该试剂与铝形成的荧光的熄灭作用，建立了荧光法测定微量氟的新方法。应用于水样和牙膏中的氟的测定，效果良好。     

<Emphasis Type="Italic">N</Emphasis>-bridged heterocycles: regiospecific synthesis of 2-methyl-4H-pyrimido[2,1-<Emphasis Type="Italic">b</Emphasis>]benzothiazol-4-ones

N-bridged heterocycles, 2-methyl-4H-pyrimido[2,1-b]benzothiazol-4-ones, have been synthesized in quantitative yield by the reaction of 2-aminobenzothiazoles with ethylacetoacetate in the presence of polyphosphoric acid involving dehydrative condensation followed by cyclization. The possibility of the formation of 4-methyl-2H-pyrimido[2,1-b]benzothiazol-2-ones has been excluded on the basis of spectral studies.     

Heteroannulated Quinazoline and Quinazolinone Derivatives from (Z)-2-[1-Benzamido-2-(3,4,5-trimethoxyphenyl)]vinyl-3,1-benzoxazin-4(3H)-one

The title compound 1 was prepared and allowed to react with a series of nitrogen nucleophiles to afford the quinazoline and quinazolinone derivatives 2–12 and tetrazole derivative 13. The IR, ¹H NMR, ¹³C NMR, and mass spectra of all the synthesized compounds were discussed.     

Novel,Simple, and Efficient Synthesis of 3-(2-(5-(Benzylideneamino)-3-phenyl-1H-pyrazol-1-yl)thiazol-4-yl)-4-hydroxy-6-methyl-2H-pyran-2-one Derivatives via a One-Pot,Four-Component Condensation Reaction

The synthesis of 3-(2-(5-(benzylideneamino)-3-phenyl-1H-pyrazol-1-yl)thiazol-4-yl)-4-hydroxy-6-methyl-2H-pyran-2-one derivatives was achieved through a one-pot, four-component reaction involving condensation of 3-(2-bromoacetyl)-4-hydroxy-6-methyl-2H-pyran-2-one, thiosemicarbazide, phenacylcyanaide, and various aryl aldehydes in dry alcohol and few drops of acetic acid under reflux condition. This four-component reaction has some advantages such as ease of handling, good yields, and easy workup. All structures of newly prepared compounds were confirmed by analytical and spectral data.     

2-[4-(Dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one: A H-bond-sensitive fluorescent probe for investigating binary mixtures of organic solvents

Molecules of electronically excited 2-[4-(dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one (a fluorescent probe) co-exist in the normal (N^*) and tautomeric (T^*) forms and emit radiation in different spectral regions. The positions (expressed in wave numbers, ν) and intensities (I) of the emission bands are strongly affected by the ability of the medium's molecules to participate in hydrogen bonding with the probe. In such cases, I_N*, I_N*/I_T*, ν_N*, ν_N* + ν_T* or ν_N* − ν_T*, depend on the concentration (over a certain range) or its base-10 logarithm (log) of the component interacting with the probe. These relationships form the basis for a quantitative assay of such compounds in binary mixtures. On the other hand, the log(I_N*/I_T*) versus ν_N* + ν_T* or ν_N* − ν_T* relationships demonstrate unique features that can be used to distinguish components (alcohols) interacting with the probe and to quantify their contents. The prospects for the analytical application of these findings are outlined briefly.     

4H-吡啶并[3,2-e][1,3]噻嗪-4-酮嘧啶衍生物的合成

2-氯烟酸异硫氰酸酯在碱性介质中与取代2-氨基嘧啶反应直接得到4H-吡啶并[3,2-e][1,3]噻嗪-4-酮嘧啶. 所合成的6个未见文献报道的目标化合物经IR, ¹H NMR和元素分析证实了其结构, 并对反应可能机理进行了探讨.