- Kinetics of Electrophilic Alkylations of Barbiturate and Thiobarbiturate Anions
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Second-order rate constants (k2) of the reactions of various barbiturate anions such as the parent barbiturate, 1,3-dimethylbarbiturate, 2-thiobarbiturate, and 1,3-diethyl-2-thiobarbiturate with diarylcarbenium ions and Michael acceptors have b
- Schade, Alexander,Tchernook, Ivan,Bauer, Mirko,Oehlke, Alexander,Breugst, Martin,Friedrich, Joachim,Spange, Stefan
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- Synthesis, Characterization, and in vitro Antibacterial Evaluation of Barbituric Acid Derivatives
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A series of 5,5′-(arylmethylene)bis[1,3-dimethyl-6-(methylamino)pyrimidine-2,4(1H,3H)-diones] have been synthesized by 2: 1 condensation of 1,3-dimethylbarbituric acid with armatic aldehydes in the presence of methylamine. The synthesized compounds have been characterized by 1H and 13C NMR, IR, and mass spectra and tested for their in vitro antibacterial activity against Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa. Some of the compounds have shown antibacterial activity exceeding that of ampicillin used as reference drug.
- Shukla,Bishnoi,Devi,Kumar,Srivastava,Srivastava,Fatma
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- Ultrasound-assisted rapid synthesis of 2-aminopyrimidine and barbituric acid derivatives
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Novel, inexpensive, and relatively expeditious procedure to achieve the synthesis of different 2-aminopyrimidine and barbituric acid derivatives is presented here, starting from readily available compounds such as guanidine hydrochloride, urea, 1,3-dialkylurea, or thiourea. Under ultrasonic irradiation, base-driven (Na2CO3, NaOH, or NaOC2H5) heterocyclization reactions of the aforementioned substrates with diethyl malonate, diethyl-2-alkyl malonate, pentane-2,4-dione, or ethyl-3-oxobutanoate yielded corresponding products. Significant advantages of this sonochemical synthetic protocol with regard to the conventional thermal methods include easy reaction setup and work-up steps, reasonably mild conditions, shorter reaction times (～30 min) and comparably high product yields. The characterization of the synthesized compounds was based on melting points, FT-IR, GC-MS, 1H-NMR techniques, and the obtained data were also checked from the previously published studies.
- Bayramo?lu, Duygu,Kurtay, Gülbin,Güllü, Mustafa
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p. 649 - 658
(2020/02/11)
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- Dynamic Covalent Metathesis in the C=C/C=N Exchange between Knoevenagel Compounds and Imines
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Fast and reversible dynamic covalent C=C/C=N exchange takes place without catalyst in nonpolar solvents between barbiturate-derived Knoevenagel (Kn) compounds and imines. A detailed study of the reaction indicates that it proceeds by an associative organo-metathesis mechanism involving the formation of a four-membered ring azetidine intermediate by addition of the imine C=N group to the C=C bond of the Kn compound. This intermediate could be generated cleanly and stabilized at low temperature by condensation of the o,p-dinitrophenyl Kn derivative with the cyclic imine 1-azacyclohexene. It was characterized by extensive NMR and mass spectrometric studies. The process described represents a genuine dynamic covalent organo-metathesis through a four-membered ring adduct as intermediate. It paves the way for the exploration of a wide set of dynamic systems involving (strongly) polarized C=C bonds and various imines, extending also into covalent dynamic polymers and polymolecular assemblies.
- Gu, Ruirui,Flidrova, Karolina,Lehn, Jean-Marie
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supporting information
p. 5560 - 5568
(2018/05/01)
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- Selective and facile oxidative desulfurization of thioureas and thiobarbituric acids with singlet molecular oxygen generated from trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane
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An efficient and facile procedure using trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane has been developed for oxidative desulfurization of thioureas and thiobarbituric acids. The reactions proceeded smoothly very fast under mild conditions in basic media at room temperature to afford the respective ureas in excellent yields. Simple procedure and work up, mild conditions, high yields, short reaction times, use of highly potent and non-toxic oxidant are the main merits of the present method.
- Azarifar, Davood,Golbaghi, Maryam
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- Synthesis and antifungal activity of substituted 2,4,6-pyrimidinetrione carbaldehyde hydrazones
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Opportunistic fungal infections caused by the Candida spp. are the most common human fungal infections, often resulting in severe systemic infections - a significant cause of morbidity and mortality in at-risk populations. Azole antifungals remain the mainstay of antifungal treatment for candidiasis, however development of clinical resistance to azoles by Candida spp. limits the drugs' efficacy and highlights the need for discovery of novel therapeutics. Recently, it has been reported that simple hydrazone derivatives have the capability to potentiate antifungal activities in vitro. Similarly, pyrimidinetrione analogs have long been explored by medicinal chemists as potential therapeutics, with more recent focus being on the potential for pyrimidinetrione antimicrobial activity. In this work, we present the synthesis of a class of novel hydrazone-pyrimidinetrione analogs using novel synthetic procedures. In addition, structure-activity relationship studies focusing on fungal growth inhibition were also performed against two clinically significant fungal pathogens. A number of derivatives, including phenylhydrazones of 5-acylpyrimidinetrione exhibited potent growth inhibition at or below 10 μM with minimal mammalian cell toxicity. In addition, in vitro studies aimed at defining the mechanism of action of the most active analogs provide preliminary evidence that these compound decrease energy production and fungal cell respiration, making this class of analogs promising novel therapies, as they target pathways not targeted by currently available antifungals.
- Neumann, Donna M.,Cammarata, Amy,Backes, Gregory,Palmer, Glen E.,Jursic, Branko S.
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p. 813 - 826
(2014/01/23)
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- Accelerated hydrolysis of α-halo and α-cyano pyridinium relative to uracil derivatives: A model for ODCase-catalyzed hydrolysis of 6-cyanoUMP
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α-Halo and α-cyano pyridiniums were found to undergo facile hydrolysis, in contrast to the sluggish reactions of corresponding uracils. The greatly enhanced rates found with pyridinium compounds have indicated a possible source of the rate acceleration seen in the hydrolysis of 6-cyanouridine 5′-monophosphate catalyzed by orotidine 5′-monophosphate decarboxylase.
- Huang, Sha,Wong, Freeman M.,Gassner, George T.,Wu, Weiming
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scheme or table
p. 3960 - 3962
(2011/09/12)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Cyclopropanation of electron-deficient alkenes with activated dibromomethylene compounds mediated by lithium iodide or tetrabutylammonium salts
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Reactions of electron-deficient alkenes with dibromomethylene compounds activated by cyano and ester groups were promoted by LiI or tetrabutylammonium bromide to afford the corresponding cyclopropanes in high yields.
- Kawai, Daisuke,Kawasumi, Katsuaki,Miyahara, Tsukasa,Hirashita, Tsunehisa,Araki, Shuki
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scheme or table
p. 10390 - 10394
(2010/02/28)
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- 5,5′-bipyridyl-2,4,6,2′,4′,6′-hexaone derivatives (hydurilic acids): Syntheses, mechanism of C-C-Bond formation and properties of the dimeric barbituric acid derivatives
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A series of hydurilic acid derivatives (5,5′-bipyrimidinyl-2,4,6,2′,4′,6′-hexaones) including several new derivatives was synthesized from 5,6-diaminouracils. Mechanisms for their formation are proposed and discussed. Furthermore, a new method for the preparation of pyrimidine-2,4,5,6-tetraone-5-oxime derivatives (violuric acids) was found starting from 5-amino-6-nitrosouracils.
- Mueller, Christa E.,Roegler, Carolin,Hockemeyer, Joerg
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experimental part
p. 703 - 720
(2009/12/26)
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- Cyclopropanation mediated by lithium iodide of electron-deficient alkenes with activated dibromomethylene compounds
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Reactions of electron-deficient alkenes with dibromomethylene compounds activated by cyanide and ester groups were promoted by LiI to afford the corresponding cyclopropanes in high yields. Georg Thieme Verlag Stuttgart.
- Kawai, Daisuke,Kawasumi, Katsuaki,Miyahara, Tsukasa,Hirashita, Tsunehisa,Araki, Shuki
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body text
p. 2977 - 2980
(2009/07/10)
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- A rapid and facile synthesis of new spiropyrimidines from 5-(2-arylethylidene-2-oxo)-1,3-dimethylpyrimidine-2,4,6-triones
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A series of new tetraazaspiro[5,5]-undec-4-ene-2,7,9,11-tetraones have been obtained by reaction of 5-(2-arylethylidene-2-oxo)-1,3-dimethylpyrimidine-2,4,6-triones with ureas. A three-component one-pot procedure to the spiranes synthesis was also developed. One-pot reaction of arylglyoxals, 1,3-dimethylbarbituric acid, and dimethylurea led to imidazolyl-1,3-dimethylbarbituric acids. Mechanisms of studied reactions were discussed.
- Gozalishvili, Lali L.,Beryozkina, Tetyana V.,Omelchenko, Irina V.,Zubatyuk, Roman I.,Shishkin, Oleg V.,Kolos, Nadezhda N.
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p. 8759 - 8765
(2008/12/21)
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- A facile synthesis of 5-acylbarbituric acids under microwave irradiations
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N-Monosubstituted and N,N'-disubstituted barbituric acids on treatment with benzoic anhydride/acetic anhydride under microwave irradiations without using any solvent provide a convenient methodology for the synthesis of 5-benzoyl/ acylbarbituric acids in moderate to high yields.
- Singh, Palwinder,Paul, Kamaldeep
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p. 1105 - 1108
(2007/10/03)
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- Cpecificy of Metylation by Dimethyl Sulfate of Barbituric Acid Salts and Alkyl Derivatives
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Metylation of mono- and dianionic forms of barbituric acid, its C- and N-alkyl derivatives with dimethylsulfate is studied. The methylation of monoanions occurs at the C5 carbon or O4(6) oxygen atoms, while that of dianions presumably at N1(3) nitrogen atoms. The selectivity of the dianions metylation at the nitrogen atoms increases in going from potassium to sodium and even more to lithium salts.
- Krasnov,Slesarev
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p. 543 - 548
(2007/10/03)
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- Photorearrangement of the ortho-cycloadduct of 6-chloro-1,3-dimethyluracil to benzene through [π4s+π2a] photocycloaddition
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Reaction pathway for the formation of the hydrogen chloride adducts of pyrimidosemibullvalene-2,4-dione derived from the photoreaction of 6-chloro-1,3-dimethyluracil in frozen benzene is interpreted by the mechanism involving the initial ortho-cycloaddition, not meta-cycloaddition, followed by the photochemical disrotatory cleavage of the cyclobutene moiety, and the successive intramolecular photo-Diels-Alder reaction of the resulting cyclooctatetraene ring.
- Ohkura, Kazue,Noguchi, Yukari,Seki, Koh-Ichi
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p. 141 - 144
(2007/10/03)
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- An unexpected linear Bronsted correlation
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The reaction of barbiturate and 1,3-dimethylbarbiturate ions with o-, p- and 2,4-dinitrobenzaldehyde was studied. The reactions of barbiturate anion with o- and p-nitrobenzaldehyde exhibit a pH-rate profile different to that the corresponding to the reactions of barbiturate and 1,3-dimethylbarbiturate ions with 2,4-dinitrobenzaldehyde. The dependence of the rate constant on the viscosity of the medium in the pH range 2-4, for all the reactions, indicates the contribution of a diffusion-controlled proton transfer from the hydronium ion to an addition intermediate, T-, in the rate-determining step. Surprisingly, in the reaction of 2,4-dinitrobenzaldehyde with barbiturate and 1,3-dimethylbarbiturate anions, the Bronsted plot for general acid catalysis for carboxylic acids of pKa between 2 to 5 gives a linear relationship with a = 0-707 (r = 0.991), whereas a = 0 is expected, considering the pKa of the addition intermediate T-. On the other hand, the point for the rate constant, considering water as a general acid catalyst, falls approximately 105 times above the corresponding Bronsfed line. The tautomerism existing in the intermediate T- permits these surprising facts to be explained.
- Baumann, Klaus D.,Brighente, Ines M.C.,Pizzolatti, Moacir G.,Yunes, Rosendo A.
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p. 545 - 551
(2007/10/03)
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- Synthesis of amphiphilic 8-decyl-1,3,6,7-tetramethyl-7,8-dihydropterine-2,4-dione
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The condensation of 5-amino-6-decylamino-1,3-dimethyluracil with 2,3-butanedione in the presence of 1N HCl gives 5N-(1'-acetyl-1'-methylmethylene)-6N-decylamino-1,3-dimethyluracil which cyclises to amphiphilic 8-decyl-1,3,6,7-tetramethyl-7,8-dihydropterine-2,4-dione (5) in the presence of 12 N HCl.
- Chauhan, S. M. S.,Tomar, Jaya,Gupta, M.
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p. 869 - 871
(2007/10/03)
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- MECHANISM OF URAPIDIL DEGRADATION IN AQUEOUS SOLUTION
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During the hydrogen ion-catalyzed hydrolysis of urapidil degradation at the bond C6-NH takes place and the formation of 1,3-dimethylbarbituric acid (DMB) and 3-propylamin (PPA).The hydroxide ion-catalyzed hydrolysis of urapidil is sequent of pseudofirst-order reaction N- amid of the malonic acid (PP) is the medial product which is formed the degradation of the bond N1-C6 and N3-C4 in the ring of uracil.In the hydroxide ion-catalyzed reaction, the compound PP splits the malonic acid and 3-propylamin (PPA') is formed.DMB, PPA, PPA' and PP compounds were isolated and its chemical structure were confirmed by spectroscopic methods. - Keywords: Urapidil; stability; mechanism of degradation
- Zajac, Marianna,Muszalska, Izabela
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p. 407 - 414
(2007/10/03)
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- ALKYLATION OF 6-METHOXYURACIL AND A NEW METHOD FOR THE SYNTHESIS OF N-SUBSTITUTED BARBITURIC ACIDS
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The alkylation of the metallic salts of 6-methoxyuracil by dimethyl sulfate and alkyl halides leads to the selective formation of 1-alkyl-6-methoxyuracils.The alkylation of these compounds leads to the formation of 1,3-substituted derivatives of 6-methoxyuracil.The acid hydrolysis of 6-methoxyuracils makes it possible to obtain 1- and 1,3-substituted barbituric acids.
- Krasnov, K. A.,Slesarev, V. I.,Selimanova, I. N.
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p. 1215 - 1220
(2007/10/02)
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- Synthesis of new uraciles having N-amino-β-, γ-, and δ-lactams
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The reaction of 1,3-dimethyl-6-methylhydrazinouracil 1 with various haloacyl halides 2 afforded N-haloacylhydrazinouraciles 3, which were converted into the corresponding lactams 4 by treatment with KOH in the presence of BTEAC.
- Okawara, Tadashi,Shono, Toshifumi,Yamasaki, Tetsuo,Furukawa, Mitsuru
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p. 1881 - 1885
(2007/10/02)
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- Studies of Pyrimidine-2,4-diones: Synthesis of Novel Condensed Pyridopyrimidines via Intramolecular Cycloadditions
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Suitably functionalised pyrimidine-2,4-diones (1) cyclised intramolecularly to yield the novel furoisoxazolopyridopyrimidines (5) and (9) in excellent yields.Remarkably, the pyrimidone nucleus was unaffected nor were there any side-reactions in this synthesis.
- Prajapati, Dipak,Bhuyan, Pulakjyoti,Sandhu, Jagir Singh
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p. 607 - 610
(2007/10/02)
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- PURINES AND PYRIMIDINES AND CONDENSED SYSTEMS BASED ON THEM. 2. SYNTHESIS OF 1-METHYL-9-AMINOXANTHINE AND 9-AMINOTHEOPHYLLINE
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The previously unknown 9-aminotheophylline and 1-methyl-9-aminoxanthine were synthesized from 3-methyl-5-amino-6-hydrazinouracil.In the case of 1-methyl-9-aminoxanthine an x-ray diffraction study of an N-amino derivative of an NH heterocycle was made for the first time.
- Kuz'menko, V. V.,Kuz'menko, T. A.,Aleksandrov, G. G.,Pozharskii, A. F.,Gulevskaya, A. V.
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p. 690 - 697
(2007/10/02)
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- Metal complexes of azomethines and process for their manufacture
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Metal complexes of azomethines of the formula STR1 are useful for coloring plastics and lacquers in yellow to red shades of excellent fastness properties.
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