A convenient synthesis of new aminopyrroloindoles via an imminium salt

Cyclization of pyrrolidinocarboxamide derivative of 2-(1-pyrrolyl) benzoic acid leads to an imminium salt which conduct to N-substituted 9-imino (and amino) 9H-pyrrolo[1,2-a]indoles.     

Base-catalyzed transformations of iminium phenylhydrazones : A new convenient synthesis of imidazo[1,2a]azacycloalkanes

β-Enamine esters react with phenyldiazonium fluoroborate to give iminium phenylhydrazone salts which, without isolation, can be converted by a base-catalysed reaction to imidazole derivatives. The latter reaction is critically dependent upon the nature of the base-component of the enamine ester. The mechanism of imidazole formation involves the following sequence of steps: (a) deprotonation of the iminium salt, (b) a symmetry-allowed 1,5-dipolar cyclization of the betaine intermediate and (c) subsequent elimination of aniline, with concomitant aromatization. The scope of the reaction as a facile approach to the synthesis of imidazole derivatives is discussed.     

A convenient cyclopropanation process of oxindoles via bromoethylsulfonium salt

A practical convenient conversion of oxindoles into the corresponding spirocyclopropyl oxindoles is achieved efficiently using bromoethylsulfonium salt, which is easily prepared on a large scale and is stable crystalline. This reaction of bromoethylsulfonium salt with different substituted unprotected oxindoles proceeded under mild condition and provided moderate yields.     

A convenient synthesis of olefins via deacylation reaction

A convenient and environmentally-friendly synthetic method of olefins via deacylation reaction is described. The reaction gives olefins by condensation of aldehydes with a variety of 1,3-dicarbonyl compounds in the presence of anhydrous potassium carbonate at room temperature in high yields (70-90%) in one step. The synthetic potential of this strategy can be used as an alternative procedure to the Wittig, Wittig-Horner reactions. The stereochemistry of the resulted olefins was determined by NOE experiment with correct radio frequency and X-ray analysis. The E/Z selectivity of the deacylation reaction depends on the α-substituents of the 1,3-dicarbonyl compounds.     

A convenient synthesis of phosphoenolpyruvate via silyl-ester intermediate

Phosphoenolpyruvate was synthesized in high yield by a simple procedure starting from pyruvic acid and dimethyl trimethylsilyl phosphite through trimethylsilylation, bromination, and the Perkow reaction.     

A new convenient synthesis of γ-keto-sulfoxide

γ-Keto-sulfoxides have been very conveniently synthesized through a series of reactions from commercially available acrolein. They were obtained as crystals and shown to be effective as the vinyl ketone equivalents.     

A convenient new synthesis of homoserine lactone

N-trityl L-homoserine lactone is synthesised in three steps from L-aspartic acid.     

A convenient method for optical resolutions via diastereoisomeric salt formation

With the advantage of the method using two immiscrible solvents and half - equivalent amount of the resolving agent, higher optical purity can be obtained than in cases of any other resolution via diastereoisomeric salt formation, besides it is a faster procedure for resolution of a new racemate as well.     

A new convenient synthesis of aroyl cyanides via the formation of cyanohydrin nitrate intermediates

The treatment of α-bromoarylacetonitriles with AgNO₃ generates cyanohydrin nitrate intermediates, which easily eliminate nitrous acid with the formation of carbonyl bond to afford aroyl cyanides in good to high yields.     

A convenient new synthesis of α-fluorocarbonyl compounds

The reaction between tertiary α-bromo ketones or aldehydes and silver tetrafluoroborate in ether affords α-fluorocarbonyl compounds. Neighboring group participation by the carbonyl oxygen is proposed to account for the products and by-products.     

A new convenient synthesis of Δ2-isoxazolines

²-Isoxazolines were obtained from the reaction of alkenes with nitrile N-oxides, generatedin situ from primary nitroalkane salts in presence of toluenesulfonyl chloride.

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Eine neue, vorteilhafte Synthese von ²-Isoxazolinen (Kurze Mitteilung)

Zusammenfassung Aus der Reaktion von Alkenen mit Nitril-N-oxiden, diein situ aus primären Nitroalkansalzen in Gegenwart von Toluolsulfonylchlorid erzeugt wurden, wurden ²-Isoxazoline erhalten.

     

A new and convenient synthesis of antazoline derivatives

Different N‐benzyl anilines were N‐alkylated with chloroacetonitrile to give the corresponding nitriles, which were subsequently condensed with ethylenediamine in the presence of thioacetamide to afford the corresponding title antazoline derivatives.     

A new and convenient synthesis of substituted benzobarrelenes

Bromination of 3-bromo-6,7-benzobicyclo [3.2.1] octa-2,6-diene at ?50°C gave anti-tribromo adduct (5) in essentially quantitative yield. The double dehydrobromination of (5) was achieved using potassium tert.- butoxide to give 2-bromo-benzobarrelene (7). Reaction of (7) with n-BuLi and subsequent quenching with CH₃I, CO₂, and dimethylformamide afforded the corresponding substituted benzobarrelenes in high yield.     

A new synthetic method for alpha-alkoxycarbonyl iminium salt and its reaction with nucleophiles

An iminium salt was easily prepared using the oxidation of amino ketene silyl acetal with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and the subsequent nucleophilic addition to this iminium species proceeded efficiently to afford alpha-amino esters in good yields.     

A convenient synthesis of substituted piperazines via aminomercuration-demercuration of diallylamines

cis and trans-2,6-Bis[bromomercuriomethyl]piperazines II which bear equal or different substituents at each nitrogen are obtained in the reaction of N-substituted diallylamines with mercury(II) acetate and aryl-amines followed by a double decomposition process with potassium bromide. Their reduction with sodium borohydride lead to the corresponding 1,4-disubstituted cis- and trans-2,6-dimethylpiperazines III. Steric factors account for the remarkable stereoselectivity observed in the preparation of compounds IIIi-IIIn in which a 3:1 cis to trans isomer ratio is found.     

A new convenient method for the synthesis of cardiolipin

A novel dichlorophosphate coupling method is developed for the synthesis of the title compound. O-Chlorophenyl dichlorophosphate can be used as a mild phosphorylating reagent to effectively couple with optically active 1,2-O-diacyl-sn-glycerol and 2-O-protected glycerol to assemble cardiolipin bearing different fatty acid chains.     

2-烷基环戊-2-烯酮的简便合成新方法

2-位取代的环戊-2-烯酮是一类重要的有机合成中间体,它们的合成方法虽然已有不少文献报道,但大都路线较长,原料难得,条件苛刻且收率较低.本文报道一个以环戊二烯为原料,仅两步反应合成2-烷基环戊-2-烯酮的简便新方法. 以聚乙二醇(PEG)作为相转移催化剂,环戊二烯在氢氧化钾作用下与卤代烷在固-液相条件下反应,可方便地得到相应的烷基取代环戊二烯,主要为1-位和2-位烷基取代异构体的混合物.通过该方法制备烷基环戊二烯较之采用钠氨于液氨中反应的通常制备方法更可取.烷基环戊二烯进一步于甲醇中经溴代及酸性水解后,即可得到2-烷基环     

A new and convenient synthesis of 13,16-diazaestrone analogs

Imidazolidine-2,4-dione was chemoselectively N-alkylated at the imidic NH with several 2-(3,4-dihydro-1-naphthalenyl)ethyl-4-methylphenylsulphonates to give the corresponding imides for the first time which on selective reduction at one of the carbonyl groups followed by cyclization in PPA gave the corresponding title compounds.     

Cannabis xxiv. A new convenient synthesis of cannabinol

The key step in a new synthetic approach to cannabinol $\text{5}$ is a remarkably smooth methoxy displacement in the o-methoxyaryloxazoline $\text{1}$ affording sterically hindered biaryloxazoline $\text{3}$.     

The application of vinylogous iminium salt derivatives to an efficient relay synthesis of the pyrrole containing alkaloids polycitone A and B

A new and efficient relay synthesis of the marine natural products polycitone A and B is described. The new strategy relies on the formation of 2,4-disubstituted pyrroles from a vinamidinium salt followed by electrophilic substitution at the 5-position of the pyrrole and Suzuki coupling at the 4-position to produce the tetrasubstituted heterocycle efficiently and with complete control of regiochemistry.