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2-Alkoxyvinyl ketones

Sodium hydroxide/alcohol 2-Alkoxyvinyl ketones and j -ketoacetals from 2-chIorovinyl ketones... [Pg.465]

Regioselective 1,2- or 1,4-addition to p-alkoxyvinyl ketones is realized by proper modification of the reagent. ... [Pg.455]

In the presence of base, alcohols and phenols add l,5-diphenylpenta-l,4-diyn-3-one (72JOU1398). At 40 °C addition occurs at both triple bonds to give a mixture of the 1,5-dialkoxy compound (411), the triketone and the pyran-4-one. On treatment with acid the former compounds are converted into the pyranone. However, at 15 °C only one triple bond is attacked giving the alkoxyvinyl ethynyl ketone (412), but this also forms the pyranone with acid (Scheme 136). [Pg.812]

Alkenylboronic acids and esters underwent conjugated addition to ct,/ -unsaturated ketones in the presence of trifluoroborane etherate589 or cyanuric fluoride (Equation (129)).590,591 Alkadienyl trifluoromethyl ketones were stereoselectively prepared from (2-alkoxyvinyl) trifluoromethyl ketones (Equation (130)).592 Alkynyl boronates can transfer the alkynyl groups regioselectively and enantioselectively to enones (Equation (131 )).593... [Pg.193]

Many N-unsubstituted pyrazoles 80 can be obtained from A-allyl-A-nitrosamides 79 (Scheme 46) <1990H(30)789>. Cyclocondensation of -alkoxyvinyl trifluoromethyl ketones 81 with thiosemicarbazide under mild conditions affords 4,5-dihydro-l//-pyrazole-l-thiocarboxamides 82, which can be easily dehydrated with concomitant thiocarboxamide group hydrolysis in concentrated sulfuric acid to give N-unsubstituted pyrazoles 83 (Scheme 47) <1998JFC(92)23>. [Pg.718]

The second-order rate constant for the reaction between methoxycarbonyl-acetylene and piperidine increases with increasing solvent polarity. This can be attributed to the increased solvation of the strongly dipolar activated complex, which is formed from neutral molecules [88], Analogous solvent effects have been observed for the nucleophilic addition of aziridine to 3-dimethylaminopropynal [89] and the addition of diethylamine to / -alkoxyvinyl methyl ketones [793],... [Pg.178]

Amino-5-trifluoromethyl-177-pyrazoles were synthesized by cyclocondensation reactions of 4-amino-4-ethoxy-1,1,1-trifluorobut-3-en-2-ones with hydrazines <2006S1485>. / -Alkoxyvinyl trifluoromethyl ketones 555 reacted with methylhydrazine to yield 3-(trifluoromethyl)-l-methylpyrazoles 556 (Equation 113) <2003JHC1087>. [Pg.79]

A series of halomethylated P-enaminones were synthesized using the IL [bmim] BF4 at room temperature (Equation 4.43). It was demonstrated that this IL is suitable as a reaction medium for the amination of P-alkoxyvinyl halomethyl ketones. This method is advantageous because of the absence of solvents, short reaction times, and good yields [84]. These compounds are now widely used as important materials in research, having interesting functionalities for use in medicinal and agricultural sciences [85]. [Pg.115]

Alkoxyvinyl trifluoromethyl ketones and -aryl- -methoxyvinyl trifluoromethyl ketones, prepared from the respective acetophenone dimethyl-acetals by reaction with trifluoroacetic anhydride, undergo cyclocondensation with thiosemicarbazide... [Pg.329]

An a-alkoxyvinyl group attached to the metal serves as an acyl anion equivalent. Reaction of di(a-methoxyvinyl)cuprate and a,) -unsaturated ketones followed by hydrolysis or ozonolysis affords 1,4-diketones and y-keto esters, respectively (Chavdarian and Heathcock, 1975). [Pg.160]

Variation of this principle of pyryhum synthesis is achieved by introducing related 1,3-biselectrophiles hke alkoxyvinyl or chlorovinyl ketones [3]. For instance, 2,6-disubstituted pyrylium salts 29 are obtained from two molecules of an aryl methyl ketone and orthoformate in the presence of strong acids (HCIO4, HBF4) ... [Pg.301]

Zanatta N, CorteUni MFM, Carpes MJS, Bonacorso HG, Martins MAP (1997) Haloactylated enol ethers 8- reactions of -alkoxyvinyl trihalomethyl ketones with guanidine hydrochloride, synthesis of -4-trihalomethyl-2-aminopyiimidines. J Heterocycl Chem 34 509-514... [Pg.557]

Bonacorso HG, Martins DB, Martins MAP, Zanatta N, Flores AFC (2005) Synthesis of alkyl-, aryl- and heteroaryl-substituted 2-[3-oxo-2,3-dihydro-lH-pyrazol-2-yl]-6(4)-trifluo-romethylpyrimidines from beta-alkoxyvinyl trifluoromethyl ketones. Synthesis 5 809-813... [Pg.557]

Zanatta N, Madruga CC, Marisco PC, Flores DC, Bonacorso HG, Martins MAP (2000) Haloacetylated enol ethers 15. Study of the regiochemistry of the cyclo-condensation of P-alkoxyvinyl trihalomethyl ketones with N-methyl thiourea. J Heterocycl Ghent 37 1213-1218... [Pg.558]

Bonacorso et al. reported that, P-alkoxyvinyl trichloromethyl ketones 72 (R i = H, Me,n-pr i-pr, i-Bu R2 = H, Me) are useful building bloeks for the synthesis of thiazolo[3,2-a]pyrimidin-5-ones 73 (Scheme 34) by reaetion with 2-aminothiazole [59]... [Pg.335]


See other pages where 2-Alkoxyvinyl ketones is mentioned: [Pg.296]    [Pg.364]    [Pg.279]    [Pg.75]    [Pg.239]    [Pg.255]    [Pg.220]    [Pg.296]    [Pg.364]    [Pg.279]    [Pg.223]    [Pg.75]    [Pg.239]    [Pg.255]    [Pg.364]    [Pg.162]    [Pg.167]    [Pg.320]    [Pg.399]    [Pg.81]    [Pg.101]    [Pg.423]    [Pg.364]    [Pg.323]    [Pg.256]    [Pg.101]    [Pg.60]    [Pg.316]   


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