Photo-oxidation of 5-acetyl-3,4-dihydropyrimidin-2(1H)-ones

Memarian, Hamid Reza; Farhadi, Asadollah; Sabzyan, Hassan; Soleymani, Mousa

doi:10.1016/j.jphotochem.2009.10.012

Cited by 21 publications

(9 citation statements)

References 19 publications

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“…Product yields ranged from 68-96%, except for compound 5 ( Table 5, Entry 4), due to the presence of the ortho-nitro group on the aromatic ring, which gave product at a yield of 55%. Both electron-withdrawing (Table 5, Entries 4-6) and electron-donating substituents (Table 5, Entries 7,8,[15][16][17]24) on the aromatic ring were well tolerated and had no considerable influence on the reaction rate. The oxidation of all sterically constrained derivatives Shanmugam et al 13 provided the explanation that this phenomenon was caused by the tautomerization of N1-H to N3 in a solution of N(1)-alkyl unsubstituted dehydrogenated product.…”

Section: Resultsmentioning

confidence: 99%

“…10,11 Nevertheless, over the past two decades, different reagents and methods have been used, more or less successfully, for this type of reaction. 22 UV light induced oxidation/Ar, 7,8 ultrasound-assisted oxidation/K 2 S 2 O 8 , 23 aerobic oxidative dehydrogenation/NHPI/Co II , 24 using Ca(OCl) 2 in aqueous media oxidation, 6 photochemical oxidation using Re(I)complex, 25 CAN/HCl, 26 microwave-assisted oxidation/I 2 , 27 light-induced free radical oxidation, 28 dehydrogenation with 1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate 29 and others. [30][31][32][33] However, despite best efforts, none of these methods have been found to be ideal with respect to prolonged reaction time, low yield, use of toxic reagents, complicated product isolation, etc.…”

Section: Introductionmentioning

confidence: 99%

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In situ formed tert-butyl hypoiodite as an efficient oxidant for rapid, room temperature, metal-free aromatization of Biginelli 3,4-dihydropyrimidin-2(1H)-ones under basic conditions

Kolarović¹,

Vinković²,

Litvić³

2016

Arkivoc

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A mild, highly efficient synthetic method was developed for the dehydrogenation of 3,4-dihydropyrimidin-2(1H)-ones employing in situ formed tert-butyl hypoiodite under basic conditions. The oxidant was prepared by the reaction of molecular iodine and potassium tertbutoxide. The reaction was carried out in dry tetrahydrofuran at room temperature and high purity products were isolated in high yields after simple work-up. The reaction times (3-10 min.) indicated the new method is superior in comparion to other literature oxidants employed under classical conditions or microwave promoted reactions. Two plausible mechanisms of dehydrogenation were proposed and the active species tert-butyl hypoiodite was characterized by UV/Vis spectroscopy method.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In situ formed tert-butyl hypoiodite as an efficient oxidant for rapid, room temperature, metal-free aromatization of Biginelli 3,4-dihydropyrimidin-2(1H)-ones under basic conditions

Kolarović¹,

Vinković²,

Litvić³

2016

Arkivoc

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“…Recently, computational methods have begun to be employed in studying the geometry of the 3,4-dihydropyrimidinones [7][8][9]. Furthermore, they used the details obtained from the optimization of the DHPMs as very useful substrate in the mechanistic studies of the oxidation reactions [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, they used the details obtained from the optimization of the DHPMs as very useful substrate in the mechanistic studies of the oxidation reactions [7][8][9]. However a vast amount of information on these DHPMs is available including determination of the crystal structures of these compounds [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Applying density functional theory on tautomerism in 3,4-dihydropyrimidin-2(1H)-ones

Farhadi

Takassi

2011

Front. Chem. China

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In the present study, the density functional theory (DFT) and Gibbs free energy calculations were performed to investigate the stability and tautomerism of C4-substituted-3,4-dihydropyrimidin-2(1H)-ones. Three different forms are possible for the ethyl 3,4-dihydropyrimidinones (ethyl 4-aryl-6-methyl-3,4-dihydropyrimidin-2(1H)-one-5-carboxylates, ethyl 4-aryl-2-hydroxy-6-methyl-1,4-dihydropyrimidine-5-carboxylates and ethyl 4-aryl-2-hydroxy-6-methyl-3,4-dihydropyrimidine-5-carboxylates) forms that the most stable form is ethyl 4-aryl-6-methyl-3,4-dihydropyrimidin-2 (1H)-one-5-carboxylates (keto-form). The obtained data showed that the substitution on the C4-substitut position can be effective on the equilibrium constant (K eq ).

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“…In comparison to DHPs, THPMs are relatively inert toward many mild and powerful oxidizing agents which readily oxidize DHPs . However, in recent years, some reagents were applied for the oxidation of THPMs using various experimental techniques. − …”

Section: Introductionmentioning

confidence: 99%

Voltammetric Oxidation of 2-Oxo-1,2,3,4-tetrahydropyrimidin-5-carboxamides: Substituent Effects

et al. 2011

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Electrochemical oxidation of a series of 20 substituted 2-oxo-1,2,3,4-tetrahydropyrimidin-5-carboxamides (THPMs) in acetonitrile has been studied using voltammetric methods at a glassy carbon electrode to investigate the influence of the substituents on the 4- and 5-positions of the heterocyclic ring. Analysis of the results shows that the electronic nature and steric hindrance of the substituents, especially their orientations toward the heterocyclic ring, determine their effects on the oxidation potential. Analysis of the computational results obtained at the DFT-B3LYP/6-31++G** level of theory suggests a mechanism in which the first electron removal occurs from either the N(1) of the heterocyclic ring or N(17) of the amide substitution. This process is followed by a fast proton removal resulting in the formation of stable allylic and/or benzylic radicals which then undergo further oxidation to the 2-oxo-1,2-dihydropyrimidin-5-carboxamides (DHPMs).

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Photo-oxidation of 5-acetyl-3,4-dihydropyrimidin-2(1H)-ones

Cited by 21 publications

References 19 publications

In situ formed tert-butyl hypoiodite as an efficient oxidant for rapid, room temperature, metal-free aromatization of Biginelli 3,4-dihydropyrimidin-2(1H)-ones under basic conditions

In situ formed tert-butyl hypoiodite as an efficient oxidant for rapid, room temperature, metal-free aromatization of Biginelli 3,4-dihydropyrimidin-2(1H)-ones under basic conditions

Applying density functional theory on tautomerism in 3,4-dihydropyrimidin-2(1H)-ones

Voltammetric Oxidation of 2-Oxo-1,2,3,4-tetrahydropyrimidin-5-carboxamides: Substituent Effects

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