Synthesis of 1-(4-methylsulfone-phenyl)-5-(4-fluoro-phenyl)-5-[14C]-1,2,3-triazole and 1-(4-sulfonamide-phenyl)-5-(4-fluoro-phenyl)-5-[14C]-1,2,3-triazole as novel carbon-14 anticonvulsant

Summary Two 1,2,3-triazole anticonvulsants, 1-(4-methylsulfone-phenyl)-5-(4-fluoro-phenyl)-5-[¹⁴C]-1,2,3-triazole and 1-(4-sulfonamide-phenyl)-5-(4-fluoro-phenyl)-5-[¹⁴C]-1,2,3-triazole, both labeled with carbon-14 in the 5-position were prepared from para-fluoro-benzonitrile-[cyano-¹⁴C].     

5-[5-(3-吡啶)-2H-四唑亚甲基]-2-芳酰氨基-1,3,4-噻二唑的合成

本文首先用5-(3-吡啶)-2H-四唑乙酰基酰肼与芳酰基异硫氰酸盐反应制备成化合物1-[5-(3-吡啶)-2H-四唑乙酰基]-4-芳酰氨基硫脲化合物1a～j, 然后用冰醋酸回流处理1a～j得到一系列化合物5-[5-(3-吡啶)-2H-四唑亚甲基]-2-芳酰氨基-1,3,4-噻二唑2a～j . 化合物1a～b在强碱介质中首先发生降解, 然后进行环化反应 .     

Cyclopropanation of 5-(allyloxymethyl)- and 5-(methallyloxymethyl)-5-ethyl-1,3-dioxanes with methyl diazoacetate

Reactions of 5-(allyloxymethyl)- and 5-(methallyloxymethyl)-5-ethyl-1,3-dioxanes with methyl diazoacetate catalyzed by Rh₂(OAc)₄ or Cu(OTf)₂ in the presence of [bmim]⁺Cl⁻, [bmim]⁺BF₄ ⁻, and [bmim]⁺PF₆ ⁻ proceed regioselectively at the C=C bond and lead to the formation of the corresponding cyclopropane-containing 1,3-dioxanes in yields up to 62%.     

Synthesis of (5R)- and (5S)-5-Methyl-5, 6-dihydrouridine Derivatives

The hydrogenation of 2′, 3′-O-isopropylidene-5-methyluridine (1) in water over 5% Rh/Al₂O₃ gave (5 R)- and (5 S)-5-methyl-5, 6-dihydrouridine (2) , separated as 5′-O-(p-tolylsulfonyl)- (3) and 5′-O-benzoyl- (5) derivatives by preparative TLC. on silica gel and ether/hexane developments. The diastereoisomeric differentiation at the C(5) chiral centre depends upon the reaction media and the nature of the protecting group attached to the ribosyl moiety. The synthesis of iodo derivatives (5 R)- and (5 S)- 4 is also described. The diastereoisomers 4 were converted into (5 R)- and (5 S)-2′, 3′,-O-isopropylidene-5-methyl-2, 5′-anhydro-5, 6-dihydrouridine (7) .     

5-nitro-5-(1′-cyclohexenyl)- and 5-nitro-5-(1′-cycloheptenyl)-3-benzyl- and 3-cyclohexyl tetrahydro-1,3-oxazines

1-(Cyclohexenyl- and 1-cycloheptenylnitromethane have been used as starting substances to yield 2-nitro-2-(1′-cyclohexenyl)- and 2-nitro-2-(1′-cycloheptenyl)-propanediol-1,3 (B) respectively. By reacting them with formaldehyde and benzylamine or formaldehydes and cyclohexylamine, derivatives of tetrahydro-1,3-oxazine (B) have been prepared. Acid hydrolysis of tetrahydro-1,3-oxazine derivatives results in the formation of 3-hydroxy-2-nitro-2-(1′-cyclohexenyl)- and 3-hydroxy-2-nitro-2-(1′-cycloheptenyl)-propylamine derivatives (E). Both aminoalcohols (E) react with formaldehyde to again yield tetrahydro-1,3-oxazine derivatives (C).

Infra-red spectra of C and E and their hydrochlorides D and F were examined and structure assignments made of the principal bands.     

Synthesis of 5-substituted 3-[5-(2,5-dimethylphenyl)-1,2-oxazol-3-yl]-1,2,4-oxadiazoles

5-(2,5-Dimethylphenyl)-1,2-oxazole-3-carbaldehyde oxime reacted with acetic anhydride in pyridine to give 5-(2,5-dimethylphenyl)-1,2-oxazole-3-carbonitrile which was converted into the corresponding amide oxime by treatment with hydroxylamine. O-Acyl derivatives of N′-hydroxy-5-(2,5-dimethylphenyl)-1,2-oxazole-3-carboximidamide underwent heterocyclization into 5-substituted 3-[5-(2,5-dimethylphenyl)-1,2-oxazol-3-yl]-1,2,4-oxadiazoles on heating in acetic acid.     

(R)-(＋)-5-甲基-5-{4-[2-(2-(5-氯吲唑基))乙氧基]苄基}-2,4-噁唑烷二酮的合成及其绝对构型的确定

以(S)-(－)-1-苯乙胺为拆分剂对外消旋的α-羟基酸进行拆分, 得到手性α-羟基酯4, 再与尿素合环、脱甲基保护, 得到关键的手性中间体(R)-(＋)-5-甲基-5-(4-羟基苄基)-2,4-噁唑烷二酮(6). 将化合物6与甲磺酸酯(8)缩合即得具有全新化学结构的标题化合物9 (ee值100%), 其结构经1 H NMR和HRMS确证. 根据拆分盐3的单晶X射线衍射分析结果及由α-羟基酯4与尿素合环生成噁唑烷二酮的反应机理, 确定标题化合物9的绝对构型为R.     

2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4- 噻唑啉酮的合成

以2-氨基-5-取代苯氧甲基-1,3,4-噻二唑(1)为起始原料, 合成了中间体2-氯乙酰氨基-5-取代苯氧甲基-1,3,4-噻二唑)-2-乙酰亚胺(2)和2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-4-噻唑啉酮(3), 化合物3进一步与取代苯甲醛发生类Knoevenagle缩合反应, 得到了一系列2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4-噻唑啉酮类化合物4a～4p. 目标化合物4a～4p的结构经IR, ¹H NMR和元素分析确证.     

Synthesis of 3- and 5-amino-5-(3)-(pyrrol-2-yl)isoxazoles

5-Amino-3-(pyrrol-2-yl)isoxazoles were selectively prepared by the reaction of 2-(2,2-dicyano-1-ethylthioethenyl)pyrroles with hydroxylamine in methanol. Under analogous conditions, 2-(2-carbamoyl-2-cyano-1-ethylthioethenyl) pyrroles with hydroxylamine gave 5-aminoisoxazoles and their structural isomers, 3-aminoisoxazoles (3-5% yield). The latter were selectively prepared by reacting 2-(2-carbamoyl-2-cyano-1-ethylthioethenyl)pyrroles with hydroxylamine in the presence of aqueous NaOH and from the products of intramolecular cyclization of 2-(2-carbamoyl-2-cyano-1-ethylthioethenyl)pyrroles, 1-ethylthio-3-iminopyrrolizines and hydroxylamine.     

The behavior of 1-(5-oxazolyl)-1-alkylidenes and 1-(5-isoxazolyl)-1-alkylidenes

Capture, rearrangement and/or fragmentation of 1-(5-oxazolyl)-1-alkylidenes and 1-(5-isoxazolyl)-1-alkylidenes are described.     

Synthesis of 1-(dimethylsulfamoyl)-2- and 5-imidazolecarboxaldehydes. Rearrangement of 1-(dimethylsulfamoyl)-5-imidazole-carboxaldehyde to the 4-carboxaldehyde

Lithiation of 1-(dimethylsulfamoyl)imidazole by n-butyllithium, followed by substitution with dimethylformamide provided 1-(dimethylsulfamoyl)-2-imidazolecarboxaldehyde in 19% yield. When 1-(dimethylsulfamoyl)-2-(tert-butyldimethylsilyl)imidazole was lithiated by sec-butyllithium, followed by methyl formate, there was obtained 1-(dimethylsulfamoyl)-2-(tert-butyldimethylsilyl)-5-imidazolecarbox-aldehyde (57%). Removal of the silyl group by acetic acid yielded 1-(dimethylsulfamoyl)-5-imidazolecarbxaldehyde ( 11 , 96%) as a gum. Isomerization of 11 took place slowly at room temperature (10 days), or faster in tetrahydrofuran solution containing triethylamine (2 hours) to form crystalline 1-(dimethylsul-famoyl)-4-imidazolecarboxaldehyde (12) in 68% yield. Proton and carbon-13 nmr spectra were analyzed to determine the structure of the isomers. However, only X-ray crystallography established the structure of 1-(dimethylsulfamoyl)-4-imidazolecarboxaldehyde, unequivocally. A mechanism for the isomerization of 11 to 12 is proposed.     

5-[5-(4-硝基苄基)-2H-四唑亚甲基]-2-芳酰氨基-1,3,4-噻二唑的合成

1-[5-(4-硝基苄基)-2H-四唑乙酰基]4-芳酰氨基硫脲(自制)在冰醋酸的存在下,经脱水、环化制备了5-[5-(4-硝基苄基)-2H-四唑亚甲基]-2-芳酰氨基-1,3,4-噻二唑。其结构经元素分析,IR,^1H NMR和MS确认。     

Asymmetric synthesis of 5-(1-hydroxyalkyl)-5-methyl-5H-furan-2-ones

The reactivity of 5-methyl-4-(pyrrolidin-1-yl)-5H-furan-2-one with aldehydes and with acyl chlorides followed by reduction was studied. The aldol condensation gave predominantly the anti aldol product when the acylation-reduction sequence led exclusively to the syn product. The use of a chiral pyrrolidine, (S)-2-methoxymethylpyrrolidine (SMP), allowed the synthesis of enantio-enriched compounds, the acylation-reduction leading to the (R,R) addition product.     

Synthesis of 5-(Arylamino)-1-benzyluracils

The synthesis of novel 5-(phenylamino)-, 5-(benzylamino)-, and 5-(phenethylamino) derivatives of 1-benzyluracil-containing different substituents in the aromatic nucleus has been carried out. Using the Hilbert-Johnson reaction it was found that N₍₁₎-monosubstitution can be achieved via alkylation of trimethylsilyl derivatives of 5-(arylamino)uracils using benzyl bromide. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 887–892, June, 2005.     

5-[5-(3-吡啶)-2H-四唑亚甲基]-2-芳酰氨基-1,3,4-噻二唑的合成

正如前文报道,l,3,4—噻二唑类杂环之所以有除草,植物生长调节,驱虫以及消炎等多种生物活性,无疑起因于噻唑母核。尽管母核上取代基不起主导作用,但它作为辅助基,在改善分子溶解性以及药效方面所产生的影响是不能忽略的。因而深入研究各种生物活性基团导入噻二唑环母核以制得多结构单元聚集于同一分子中的噻二唑新衍生物,对于开发多功能新药具有一定的理论意义和实际价值。     

Rapid spectrophotometric determination of zirconium with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

Zirconium reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the pH range 3.8-5.8 to form a red chelate that is soluble in methanol-water mixtures. The absorbance of the 1:3 complex obeys Beer's law over the zirconium concentration range 0.02-0.44 mug/ml and has a molar absorptivity of 1.54 x 10(5) 1.mole(-1). cm(-1) at 585 nm. The formation constant is log beta(3) = 16.15. Of 59 species studied, only EDTA, Ga, In, Ti, Hf and V(V) interfere seriously.     

5-(5-氯-2-吡啶偶氮)-2,4-二氨基甲苯的电分析特性研究

本文采用多种电化学方法研究了5-Cl-PADAT的电分析特性,求得了该化合物的电极反应电子转移数,扩散系数及电极反应标准速率常数,研究了其在滴汞电极上的吸附性质,提出了可能的电极还原过程。并且应用光度法测定了化合物的酸离解常数。     

Synthesis and reduction of 5-halo-and 5-nitro-1-(benzofuran-3-yl)-2-phenylethanones

Novel 1-(2-alkylbenzofuran-3-yl)-2-(4-methoxyphenyl)ethanones having a halogen or nitro group in position 5 of the benzofuran ring were synthesized starting with the corresponding 2-(2-formylphenoxy)alkanoic acids. 1-(2-Alkylbenzofuran-3-yl)-2-phenylethanols containing bromine or chlorine atom were prepared in high yields by reduction of the corresponding ethanones with lithium aluminum hydride. Selective catalytic reduction of nitro 1-(2-alkylbenzofuran-3-yl)-2-(4-methoxyphenyl)ethanones to the corresponding amino compounds under Pd/C in room temperature was achieved. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1158–1166, August, 2006.     

A Convenient One-Step Synthesis of 5-(α-alkanonyl) and 5-(α-Cyclanonyl)-4-Pentanolides

The thermolysis of t-butyl perpent-4-enoate in ketones leads to the formation of 5-(α-alkanonyl) and 5-(α-cyclanonyl)-4-pentanolides with fairly good yields.     

Spectrophotometr1c determination of cadmium with 2-(5-chloro-2-pyridylazo)-5-dimethylaminophenol

The reaction between cadmium and 2-(5-chloro-2-pyridylazo)-5-dimethylaminophenol (5-Cl DMPAP) in aqueous alcohol media at pH 8.8-10.7 results in an intense violet colour which is stable for at least 8 hr. The composition is 2:1 reagent:metal and the formation constant (5.29 +/- 0.01) x 10(18). Beer's law is obeyed up to 1.34 ppm of cadmium at 550 nm. The optimal concentration range (Ringbom) is between 0.16 and 0.72 ppm. The apparent molar absorptivity at 550 nm is (1.20 +/- 0.01) x 10(5) l.mole(-1). cm(-1), making the sensitivity one of the highest known. The interference due to copper(III), iron(III), cobalt(II), nickel(II), gold(III), zinc(II) and manganese(II) can be suppressed.