Convenient Methodology for the Synthesis of Trialkylhydrazines

A convenient methodology, based on the addition of organolithium compounds to N-nitrosamines, was developed for the synthesis of substituted hydrazones and trialkyl hydrazines. The reaction is very sensitive to the reaction conditions, particularly the [RLi]–[nitrosamine] ratio. For molar ratios of 1–1.2, an almost quantitative conversion to the N = O bond addition products (i.e., alkylhydrazones) can be obtained in very good yields, with any remaining nitrosamine. Using greater molar ratios (in the range of 3–5), a second addition occurs, and branched trialkyl hydrazines are obtained, in good yields, with variable amounts of hydrazone remaining. Substituted hydrazines are known to have useful commercial applications and remarkable biological activities. A wide diversity of trialkyl hydrazines could be synthesized by using two different organolithiums.     

Convenient Synthesis of Substituted 2-Phenylbenzothiazoles Using Solid-Supported Triphenylphosphine

We report an improved procedure using solid-supported triphenylphosphine for the concise synthesis of biologically relevant 2-phenylbenzothiazoles featuring a variety of substituents on both the benzothiazole and phenyl rings. Substituted 2-phenylbenzothiazoles were synthesized by heating equimolar quantities of 2-aminothiophenol disulfides with benzaldehydes and p-toluenesulfonic acid in the presence of polymer-supported triphenylphosphine in dimethylformamide/toluene. Appealing features of this new method include simple isolation of product (removal of phosphine oxide by-product by filtration), avoidance of column chromatography, and good yields of substituted 2-phenylbenzothiazole products.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

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 Aryl Phosphorodichloridothioates Using Phase Transfer Catalyst

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

Convenient Synthesis of Monosubstituted Arylferrocenes Using PEG-1000 as Phase-Transfer Catalyst

A new approach for the synthesis of monosubstituted arylferrocenes based on the coupling of aryldiazonium salts with ferrocene using PEG-1000 as an efficient phase-transfer catalyst was developed. The present method is applicable to many kinds of substituted aromatic amines, providing good to excellent yields of desired products.      

苯并三氮唑类化合物的合成及生物活性

设计并合成了6种新的苯并三氮唑类化合物,其结构均经^1H NMR和IR确认。初步测定了其生物活性．结果表明6种化合物对小白菜的胚根、根和苗的生长均具有一定的调节作用。     

Convenient Synthesis of Cerpegin

A convenient procedure for the preparation of cerpegin is described.     

A Convenient Synthesis of N-Arylanthranilic Acids Using Ultrasonics in the Ullmann-Goldberg Condensation

Ultrasonics efficiently promotes the Ullmann-Goldberg condensation of 2-halogenobenzoic acids and primary aromatic amines to obtain various N-arylanthranilic acids.     

A Convenient Synthesis of Thioacetates and Thiobenzoates Using Silica-Gel Supported Potassium Thioacetate

Abstract

A simple and efficient procedure has been developed for the synthesis of thioesters by a reaction of alkyl halides with silica-gel supported potassium thioacetate or thiobenzoate under mild conditions.     

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.     

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     

Convenient Synthesis of 2-Vinylindoles

A convenient, two-step synthesis of 2-vinylindoles is described from the easily accessible (E)-ethyl-α-allyl-2-nitrocinnamates. Ethylcinnamates (1a and 1b) on reaction with triethylphosphite provide ethyl-2-allylindole-3carboxylates (2a and 2b ) along with minor amounts of their N-ethoxyderivatives (4a and 4b). Alkaline hydrolysis of 2a and 2b provide (E)-2-vinylindoles 3a and 3b in 60 and 67% yield respectively.     

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.     

Convenient and Efficient Synthesis of Some Novel Fused Thieno Pyrimidines Using Gewald's Reaction

Abstract

Several functionalized thienopyrimidines were synthesized by a facile synthetic method, which includes Gewald's reaction, and were characterized by spectral and analytical data. These functionalized thienopyrimidines were converted to various new chemical entities of biological importance, such as 2-piperazinymethyl thienopyrimidines (6, 8), 4-dimethylaminoethoxy thienopyrimidines (11), and 3-dimethylaminoethyl thienopyrimidines (12). All the compounds thus synthesized were screened for their invitro biological activities. Some of the compounds displayed promising serotonin 5-HT₆ receptor antagonist activities.

(+)-柳杉酚的简便合成

报道了两种(+)-柳杉酚(6)的简便合成路线。路线1:脱氢枞胺(1)经脱氨还原,12-位Friedele-Crafts乙酰化,Baeyer-Villiger氧化,7-位氧化和水解5步反应合成了6,总产率18.6%。路线2:1经脱氨还原和7-位氧化反应制得7-氧代脱氢松香烷(7);7与过氧化邻苯二甲酰反应,然后水解合成了6,总产率22.0%。6的结构经1H NMR,IR,TOF-MS和元素分析确证。     

Convenient Synthesis of N-Trimethylsilylaminotitanium Trichlorides

Bis(N-trimethylsilylamino)plumbylenes 1 {[Me₃Si(R)N]₂Pb with R = ^tBu ( a ), Me₃Si ( b ), 9-(9-borabicyclo[3.3.1]nonyl) ( c )} react smoothly with an excess of TiCl₄ to give PbCl₂ and N-trimethylsilylaminotitanium trichlorides 3 a – c . In contrast, the analoguous reaction of the corresponding stannylenes 2 a – c leads to mixtures containing unidentified Ti^III compounds, the amides 3 a or 3 b , bis[bis(trimethylsilyl)amino]titanium dichloride 4 b and bis(amino)tin dichlorides 5 a – c . The crystal structure of 3 a was determined by X-ray structural analysis. Compound 3 a is a dimer in the solid state with distorted trigonal pyramidal surroundings of the titanium atoms. Each titanium atom bears two μ²-Cl ligands which are in axial (d_Ti–Cl = 250.7(1) pm) and equatorial positions (d_Ti–Cl = 247.0(1) pm) and two terminal chloro ligands, one in axial (d_Ti–Cl = 228.0(1) pm) and one in equatorial position (d_Ti–Cl = 221.1(1) pm). The equatorial Ti–N bonds are short (183.8(2) pm).     

Convenient Synthesis of Dicyclohexyldithiophosphinic Acid

Dicyclohexyldithiophosphinic acid was synthesized by a three-step strategy through the Grignard reaction of PSCl₃ with cyclo-C₆H₁₁MgBr and the P-P bond-cleavage reaction of the intermediate. The ¹H NMR data of ammonium dicyclohexyldithiophosphinate 4 and dicyclohexyldithiophosphinic acid 5 were characterized by ¹H-¹H correlation spectra.     

Novel Convenient Synthesis of Mitiglinide

A novel convenient synthesis of the hypoglycemic agent mitiglinide was developed. (2S)‐4‐[(3aR,7aS)‐Octahydro‐2H‐isoindol‐2‐yl]‐4‐oxo‐2‐benzyl‐butanoic acid (6) was prepared by selective hydrolysis of ethyl 4‐[(3aR,7aS)‐octahydro‐2H‐isoindol‐2‐yl]‐4‐oxo‐2‐benzyl‐butanoate (5) using α‐chymotrypsin; the latter was prepared by a novel facile route from (3aR,7aS)‐octahydro‐2H‐isoindole. The overall yield was 25.6%.     

Novel Convenient Synthesis of Rivastigmine

A novel and convenient synthesis of rivastigmine has been reported. This procedure provides high yield and excellent enantiomeric excess (100% ee) starting from the diastereromerically pure (S)-1-(3-methoxyphenyl)-N-[(S)-1-phenylethyl] ethanamine.