A Highly Stereoselective Synthesis of 2－Carbomethoxy－3－aryl－4－carboethoxy－5－methyl－cis－2，3－dihydrofurans

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Convenient synthesis of 3-aminomethylenedihydrofuran-2-ones

A simple and convenient synthesis of a series of 3-aminomethylenedihydrofuran-2-ones from the reaction of 3-trichloroacetyl-4,5-dihydrofuran with amines, is presented.     

A facile stereoselective synthesis of 2-perfluoroalkyl-3a,4,5,6-tetrahydroimidazo[1,5-b]isoxazoles

Methyl 2-perfluoroalkynoates 2 reacted readily with cyclic nitrones 1 via 1,3-dipolar cycloaddition at room temperature to give 2-perfluoroalkyl-3a,4,5,6-tetrahydroimidazo[1,5-b]isoxazoles 3 in good to excellent yields with high diastereoselectivity and regioselectivity.     

Organosulfur phosphonium salt-mediated synthesis of functionalized thiopyran derivatives

Methyl 4-oxotetrahydro-2H-thiopyran-3-carboxylate as a CH-acid undergoes a mild reaction with acetylenic esters in the presence of triphenylphosphine to produce phosphorus ylides possessing thiopyran-4-one ring moiety. The resulted phosphorus ylides when heated in toluene afforded functionalized thiopyran derivatives through intramolecular Wittig reaction.     

Sequential cross-metathesis/phosphorus-based olefination: stereoselective synthesis of 2,4-dienoates

A variety of stereodefined 2,4-dienoates have been prepared in a stereoselective manner by sequencing olefin cross-metathesis (CM) with phosphorus-based olefination reactions (Wittig and Horner-Wadsworth-Emmons) in good yield using commercially available reagents.     

Unexpected Synthesis of Novel 3-Allyl-5-(arylidene)-2-thioxo-thiazolidin-4-ones in Reactions of 3-Allylrhodanine with 2-Arylidene-4-methyl-5-oxopyrazolidinium Ylides

Abstract

The reaction of 3-allylrhodanine with 2-arylidene-4-methyl-5-oxopyrazolidinium ylides proceeded unexpectedly to form novel 3-allyl-5-(arylidene)-2-thioxo-thiazolidin-4-ones 6a–k in good yields. All structures have been formulated on the basis of their spectral (IR, NMR, MS) data and elemental analyses. In addition, the structure of compound 6a was confirmed by means of x-ray crystallographic analysis.     

Stereoselective synthesis of (Z)-γ-cyano-β-perfluoroalkyl-β,γ-unsaturated esters

(Z)-γ-Cyano-β-perfluoroalkyl-β,γ-unsaturated esters have been synthesized by the reaction of perfluoroacylated phosphonates with organozinc reagent in 50-71% (three steps) yields.     

Novel synthesis of 2-amino-3-hetaryl-4(5H)-oxothiophenes

3-Cyano-3-hetaryl-2-oxopropyl thioacetates were obtained by the acylation of hetarylacetonitriles with acetylmercaptoacetyl chloride. Their reaction with amines led to the formation of 2-amino-3-hetaryl-4(H)-oxothiophenes. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 680–685, May, 2006.     

Convenient synthesis of 4-tert-butyl 2-ethyl 3-amino-1-benzyl-5-dialkylamino-1H-pyrrole-2,4-dicarboxylate derivatives

Optimization details and limitations of a novel synthetic method of 4-tert-butyl 2-ethyl 3-amino-1-benzyl-5-dialkylamino-1H-pyrrole-2,4-dicarboxylate derivatives are herein disclosed. This synthesis consists of four steps that include a highly selective cyclization, and can be carried out from starting materials to target compounds without column chromatography purification. The high selectivity is controlled by lithium coordination and steric hindrance caused by tert-butyl ester.     

Convenient synthesis of 5-methylene-4-substituted-2(5H)-furanones

A synthesis of novel 4-(substituted)benzyl-5-methylene-2(5H)-furanones involving Stobbe condensation of substituted aldehydes with ethyl levulinate followed by treatment with acetic anhydride in the presence of sodium acetate, has been developed.     

Synthesis of 2-amino-5-chloro-3-(trifluoromethyl)benzenethiol and conversion into 4H-1,4-benzothiazines and their sulfones

The synthesis of 2-amino-5-chloro-3-(trifluoromethyl)benzenethiol was achieved by hydrolytic cleavage of 2-amino-6-chloro-4-(trifluoromethyl)benzothiazole which was prepared by cyclization of 4-chloro-2-(trifluoromethyl)phenylthiourea by bromine in chloroform, the phenylthiourea was prepared by the reaction of 4-chloro-2-(trifluoromethyl)aniline with ammonium thiocyanate in hydrochloric acid. Condensation and oxidative cyclization of 2-amino-5-chloro-3-(trifluoromethyl)benzenethiol with β-diketones/β-ketoesters provided 4H-1,4-benzothiazines. Fluorinated sulfones were obtained by oxidation of the corresponding benzothiazines with 30% hydrogen peroxide in glacial acetic acid. The structures of the newly synthesized compounds were confirmed by spectral studies.     

Convenient synthesis of trifluoromethylated 2-pyrrolidone and 2-pyrrolone derivatives

The reaction of a set of enamines with methyl trifluoropyruvate and its imine was investigated. As a result, a simple procedure for synthesis of trifluoromethylated 2-pyrrolidone and 2-pyrrolone derivatives has been developed.     

Cu(I)-catalyzed coupling reactions of fluorinated imidoyl halides with terminal alkynes: Convenient synthesis of fluorinated alkynyl imines

The first example of coupling reactions of fluorinated imidoyl halides with terminal alkynes catalyzed by CuI is presented. Each reaction needed no ligand, and fluorinated alkynyl imines were obtained with excellent yields.     

Convenient synthesis of furan-3-carboxylic acid and derivatives

A convenient synthesis of furan-3-carboxylic acid and derivatives from aromatization of 4-trichloroacetyl-2,3-dihydrofuran followed by nucleophilic displacement of the trichloromethyl group by hydroxide, alcohols, and amines, is presented.     

4—取代苯基—6—甲基—5—硫代—1,2,4—三嗪—3—酮的合成

合成了一系列新的４，６－二取代－５－硫代－１，２，４－三嗪－３－酮类化合物，并用元素分析、ＩＲ、＾１Ｈ ＮＭＲ及ＭＳ对其结构进行了表征。     

固载杂多酸催化合成2,4-二甲基-2-(4-甲基-3-戊烯基)-1,3-二氧五环

环缩酮类香料化合物[1 3]是在催化剂存在下由相应的酮和多元醇经缩合反应而制得。已报道的催化剂有质子酸[1]、固体酸[2,3]和某些金属盐类[4～7]等。本文以大孔阳离子交换树脂固载磷钨酸催化6 甲基 5 庚烯 2 酮与1,2 丙二醇的缩合反应,催化剂活性高,且可重复使用,后处理简便。1　实验1 1　仪器和试剂ＷＹＡ 1Ｓ阿贝折光仪;ＰＥ 2400ＣＨＮ元素分析仪;ＰＥ 783红外光谱仪。6 甲基 5 庚烯 2 酮、1,2 丙二醇、钨酸钠、磷酸氢二钠、盐酸等均为分析纯;大孔阳离子交换树脂(Ｄ001 ＣＣ型)。1 2　制备1 2 1　催化剂　以二水钨酸钠和十二水磷酸氢…     

Convenient one-step synthesis of 5-carboxy-seminaphthofluoresceins

The one-step synthesis and characterization of a series of regioisomerically pure 5-carboxy-seminaphthofluoresceins (5-carboxy-SNAFLs) is reported. The optical properties were determined in aqueous buffer at around biological pH, and highly pH sensitive, large Stokes-shift fluorophores with emission in the deep-red to near-infrared region were identified.     

Convenient synthesis of arylpropargyl aldehydes and 4-aryl-3-butyn-2-ones from arylacetylenes and amide acetals

The reaction of arylacetylenes 1 and N,N-dimethylformamide dimethylacetal (2a, DMF-DMA) afforded the corresponding arylpropargyl aldehydes 3 in moderate yields. Similarly, the reaction of 1 and N,N-dimethylacetamide dimethylacetal (2b, DMA-DMA) gave 4-aryl-3-butyn-2-ones 4.