A convenient synthesis of 5-acyl-6-substituted 3-cyano-2(1H)-pyridinones

2-Dimethylaminomethylidene-1,3-diketones are useful synthons for the construction of 5-acyl-6-substituted-3-cyano-2(1H)-pyridinones. The reaction of these 1,3-diketones and the anion of cyanoacetamide gave the title compounds. When the 1,3 diketone contained different alkyl or aryl groups, mixtures of regioisomers were formed. To circumvent this problem, dimethylaminomethylidene hydrazones, regioselectively prepared from dimethylhydrazino enones and dimethylformamide dimethyl acetal were reacted with cyanoacetamide anion followed by acid hydrolysis to give the title compounds.     

A novel convenient synthesis of 5-acyl-1,2-dihydropyrimidin-2-ones via 4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones

A novel four-step methodology for the synthesis of 5-acyl-1,2-dihydropyrimidin-2-ones has been developed. The reaction of readily available N-[(1-acetoxy-2,2,2-trichloro)ethyl]ureas with Na-enolates of 1,3-diketones or β-oxoesters followed by heterocyclization-dehydration of the oxoalkylureas formed gave 5-acyl-4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones. The latter, in the presence of NaH, eliminate CHCl₃ to give the target compounds.     

A convenient synthesis of 6-demethoxycapillarisin

A convenient and effective method for the synthesis of 6-demethoxycapillarisin was described.The highlight was involved in asimple access to the key intermediate 2-ethylthio-5,7-dimethoxy-4H-chromen-4-one from the inexpensive 2,4,6-trihydroxyacetophenone,using AlCl3 as the demethylation reagent.     

A convenient and general synthesis of 5-vinylhexofuranosides from 6-halo-6-deoxypyranosides

The synthesis of five different 5,6-dideoxyhex-5-enofuranosides ($\text{5}$, $\text{7}$, $\text{9}$ and $\text{11}$) proceeds in 30–60% overall yield in two steps from commercially available 1-$\text{0}$-methyl pyranosides by reductive β-elimination of the intermediate 6-bromo-6-deoxypyranosides.     

A convenient synthesis of 2-nitroindoles

The reaction of 2-iodo- and 2-bromoindoles with silver nitrite in aqueous acetone affords the corresponding 2-nitroindoles in modest to good yields.     

A convenient laboratory synthesis of 2-oxazoline

The reaction of 2-chloroethylformamide ( 1a ) with sodium hydride, in N-methyl-2-pyrrolidone, at reduced pressure, gave anhydrous 2-oxazoline ( 2a ) in good yield.     

A convenient synthesis of 2-tetrahydrofuranyl ethers

[reaction: see text] A wide spectrum of alcohols and phenols are readily transformed to the corresponding 2-tetrahydrofuranyl ethers in good to excellent yields using CrCl2 and CCl4 in THF under nearly neutral conditions at room temperature.     

A convenient synthesis of 2-chromonecarboxylic acids

Knoevenagel condensation of the β-ketosulfinyl intermediate II with butyl glyoxylate afforded the butyl 2-hydroxy-4-(2-hydroxyphenyl)-3-methylsulfinyl-4-oxobutyrates (III). Compounds III are versatile intermediates for the synthesis of either 2-chromonecarboxylates (V) or 2-carboxy-methylene-3-coumaranone esters (VII).     

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 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 convenient synthesis of crotylbenzaldehydes and 2-methylformyl-chromans

Condensation of hydroxybenzaldehydes viz., 2,3,4-trihydroxy-, 2,4-dihydroxy-, 2,4-dihydroxy-6-methyl-, and 2,4-dihydroxy-3-iodo-6-methylbenzaldehydes with buta-1,3-diene in the presence of orthophosphoric acid yields crotylbenzaldehydes in one step. The latter compounds on cyclisation afford the corresponding 2-methylformylchromans.

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Eine einfache Synthese von Crotylbenzaldehyden und 2-Methylformyl-chromanen

Zusammenfassung Die Kondensation von Hydroxybenzaldehyden (2,3,4-Trihydroxy-, 2,4-Dihydroxy-, 2,4-Dihydroxy-6-methyl-, und 2,4-Dihydroxy-3-jod-6-methyl-benzaldehyd) mit Buta-1,3-dien in Gegenwart von Orthophosphorsäure ergibt in einer Stufe Crotylbenzaldehyde. Diese lassen sich durch Cyclisierung zu den entsprechenden 2-Methylformylchromanen umsetzen.

     

A convenient synthesis of 2-aminopyridine-3-carbonitriies

The 5- and/or 6-alkyl substituted derivatives of 2-aminopyridine-3-carbonitrile were synthesized via dienamine intermediates (3) produced by the addition-elimination reaction of various enamines to methoxymethylene malondinitrile. The reaction can be carried out without the isolation of the dienamine intermediates.     

Thallium in organic synthesis. 68. A convenient synthesis of 2-phenylindoles from anilides

Thallation of anilides with TTFA in a mixture of TFA and ether gives ortho-thallated derivatives, which yield 2-acetamido-tolanes upon reaction with copper(I) phenylacetylide in acetonitrile. Treatment of the latter compounds with palladium(II) chloride results in ring closure to give 1-acyl-2-phenylindoles, from which 2-phenyl-indoles are obtained by alkaline hydrolysis.     

A convenient synthesis of O-alkyl thioesters from esters

O-Alkyl thioesters may be prepared from the corresponding carboxylic esters by successive treatment with lithium diisopropylamide, chlorotrimethylsilane, and hydrogen sulfide.     

The synthesis of 5- and 6-acyl-2(1H)-pyrimidinones

The synthesis of 5-acyl-2(1H)-pyrimidinones is described. In addition, one example of the hitherto unknown 6-acyl-2(1H)-pyrimidinones has been prepared.