A Convenient Synthesis of N-Methoxy-N-Methylamides from Carboxylic Acids

Carboxylic acids can be converted to their corresponding N-methoxy-N-methylamides in high yields using 2-chloro-1-methylpyridinium iodide as the coupling agent. The reaction proceeds without racemization when chiral carboxylic acids are used as the starting material.     

Convenient Synthesis of a Library of Discrete Hydroxamic Acids Using the Hydroxythiophenol (Marshall) Resin

Several resins have reportedly been used to synthesize hydroxamic acids except for the hydroxythiophenol (Marshall) resin. Herein, we report the use of the Marshall resin to synthesize hydroxamic acids from carboxylic acids and its application to convert a library of 14 discrete aliphatic and aromatic carboxylic acids including N-protected amino acids to their corresponding hydroxamic acids in good yields.     

载体试剂在有机合成中应用的研究(Ⅱ)——芳香醚的合成

某些芳香族混醚如对硝基苯基间甲苯醚(甲草醚)、2,4-二氯苯基-4'-硝基苯基醚等均是商品化的除草剂。近年来,相转移催化法合成醚类已有报导。     

A Convenient Synthesis of 2-Alkyl-3-Deutero-2-Cyclopropene-1-Carboxylic Acids

Cyclopropenes possess very high strain energies¹ and their organic and organometallic chemistry has been widely studied. They are reactive dienophiles in the Diels-Alder reaction,² and they undergo ring opening reactions under vigorous photochemical³ and thermal⁴ conditions.⁵ Transition metal promoted ring opening reactions of cyclopropenes occur under very mild conditions,⁶ and have also been the subject of a theoretical study.⁷     

A Convenient Synthesis of Aryl Phosphorodichloridothioates Using Phase Transfer Catalyst

A simple, convenient synthesis of aryl phosphorodichloridothioates using tetra-butylammonium bromide (TBAB) as phase transfer catalyst is described.     

Facile and Convenient Synthesis of 5-Arylalkylidenerhodanines by Electrocatalytic Crossed Aldol Condensation

Abstract

An electrochemically induced catalytic crossed Aldol condensation of one equivalent of rhodanine with various aromatic aldehydes and ketones in ethanol in an undivided cell in the presence of sodium bromide as an electrolyte results in the formation of the corresponding 5-arylalkylidenerhodanines in 80–96% yield with reactions in 40 min.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Convenient Synthesis of Julolidines Using Benzotriazole Methodology

Reaction of N,N-bis[(benzotriazol-1-yl)methyl]aniline (2) with 1-vinylpyrrolidin-2-one gives a mixture of diastereomeric 1,7-bis(2-oxopyrrolidin-1-yl)julolidines 3. After reduction of 3 with LAH, the predominant trans diastereomer of 1,7-di(pyrrolidin-1-yl)julolidine (4) is separated. Reaction of 2 with ethyl vinyl ether yields predominantly trans-1,7-di(benzotriazol-1-yl)julolidine (11). Stepwise synthesis from tetrahydroquinoline 15 gives access to julolidines with two different substituents on C-1 and C-7. Reaction of 1-[(benzotriazol-1-yl)methyl]-1,2,3,4-tetrahydroquinoline (25) with enolizable aldehydes gives a mixture of tetrahydroquinolines 26-29 which are converted into single julolidine products upon treatment with sodium hydride, LAH, or phenylmagnesium bromide. Reactions of 1,2,3,4-tetrahydroquinolines with benzotriazole and 2 molar equiv of enolizable aldehydes gives 1,2,3-trisubstituted julolidines 38-41, which with lithium aluminum hydride, sodium hydride, or a Grignard reagent produce single diastereomers of products 42, 43, and 45, respectively.     

A Convenient Synthesis of Phenoxy Carboxamides from Phenols Using the Mitsunobu Reaction

An efficient method for the direct conversion of phenols to phenoxy carboxamides is presented. This synthetic methodology is utilized to produce potent human leukocyte elastase inhibitors.     

Efficient and Convenient Method for Synthesis of Benzofuran-3-acetic Acids and Naphthafuran-acetic Acids

Herein, we report an efficient and convenient method for synthesis of benzofuran-3-acetic acids and naphthafuran-acetic acids 5a–p by the reaction of substituted-4-bromomethylcoumarins with aqueous sodium hydroxide at refluxing temperature. The obtained products are characterized by infrared, ¹H NMR, ¹³C NMR, and mass spectral data. Structures 5a and 5e are confirmed by their single x-ray diffraction studies. The advantages of this method are good yields, easy workup, and no chromatographic purifications.     

Hypervalent Iodine in Synthesis XXXV: A Simple and Convenient Stereospecific Synthesis of Vinyl Esters of Dithiocarbamic Acids

Vinyl esters of dithiocarbamic acids have been stereospecifically prepared by the reaction of sodium dithiocarbamates with vinyi(phenyi)iodonium tetrafluoroborates with retention or inversion of the configurations.     

A Convenient Access to Chiral Sulfonic Acids

Neomenthyl and trans myrtanyl sulfonic acids are obtained, free from inorganic salts, starting from the corresponding chiral alcohols.     

片段缩合法合成亮丙瑞林

将亮氨酸作为C末端氨基酸,采用片段缩合策略(2+7)合成亮丙瑞林.液相法合成困难序列Fmoc-Arg(Pbf)-Pro-NHEt时,以DIC为缩合试剂,THF作为溶剂,Pro-NHEt·HCl与Fmoc-Arg(Pbf)-OH的物质的量比为1:1.25,产率可达84.8%.采用固相法合成的全保护七肽片段产率为81.3%.全保护的七肽片段与Arg(Pbf)-Pro-NHEt在液相中缩合时,以DMF:DMSO(V:V=1:1)为溶剂,HATU/HOBt/DIEA为缩合剂,得全保护的九肽.切割侧链后得到目标产物亮丙瑞林.     

A Convenient Synthesis of 3- and 3,4-Substituted 4,5-Dihydroisoxazole-5-Acetic Acids

The 4,5-dihydroisoxazole-5-acetic acids 4a-j were prepared from the ketoximes 1a-j, 2,2-dimethyl-5-methoxymethylene-1,3-dioxan-4,6-dione (2) and butyllithium in yields from 35 to 79%.     

无溶剂研磨条件下芳基亚甲基麦氏酸的合成

将芳香醛、麦氏酸与NaHCO₃置于研钵中, 在无溶剂存在下通过研磨可以发生缩合反应, 反应产率良好.     

Side Reactions in the Phase Transfer Catalysed Wittig-Horner Synthesis. A Convenient Method of Preparation of Hydroxycinnamic Acids

Reaction between triethylphosphonoacetate and acetylated hydroxy aromatic aldehydes gives hydroxycinnamic acids except for ortho acetylated compounds where the Knoevenagel product is sometimes obtained.     

A Convenient One Pot Synthesis of Esters of Carboxylic Acids from Alkyl or Aryl Halides

Esters of carboxylic acids were readily synthesized from alkyl or aryl halides by reacting the corresponding Grignard reagents with dimethyl, diphenyl or ethylene carbonates.     

A Convenient Synthesis of Sendaverine

Sendaverine was isolated from Corydalis aurea willd by Manske and it was found to possess a tetrahydro-isoquinoline skeleton¹. The structural formula of the alkaloid has been established by the unambiguous synthesis by Kametani² and Miwako Mori et al.³     

A Convenient Synthesis of O-Alkyl-S-allenyl-Phosphoramidates

Ten title compounds 2a-j were synthesized by utilising mercuric (I) catalyzed thiono-thiolo rearrangement of O-propargyl-O-alkyl-pho-sphoramidothionates (1a-j) in HAc-NaAc buffer (PH=3.6). The yield of compounds 2a-e and 2f-j is 58–67% and 12–41%. This is the example of [3,3]-sigmatropic type rearrangement of 1,5-enyne system in thionop hosphoramidate chemistry.     

A Convenient Synthesis of Tryptamines

Reaction of tosylmethyl isocyanide with substituted formyl indoles gave the nitrile with one more carbon atom. Hydrogenation of this nitrile afforded the corresponding tryptamine.     

A Convenient Synthesis of Thioimidates

Thioimidates are useful reagents in preparative organic chemistry: for example, they are key intermediates for the synthesis of β-lactams bearing a thioether function at position 4, via an “acid chlorideimine” type reaction.¹