67-52-7Relevant articles and documents
Single-Crystal X-ray Diffraction Structure of the Stable Enol Tautomer Polymorph of Barbituric Acid at 224 and 95K
Marshall, Madalynn G.,Lopez-Diaz, Valerie,Hudson, Bruce S.
, p. 1309 - 1312 (2016)
The thermodynamically stable enol crystal form of barbituric acid, previously prepared as powder by grinding or slurry methods, has been obtained as single crystals by slow cooling from methanol solution. The selection of the enol crystal was facilitated by a density-gradient method. The structure at 224 and 95K confirms the enol inferred on the basis of powder data. The enol has bond lengths that are consistent with the expected bond order and with DFT calculations that include treatment of hydrogen bonding. In isolation, the enol is higher in energy than the tri-keto form by 50kJ mol-1 which must be more than compensated by enhanced hydrogen bonding. Both crystal forms have four normal H-bonds; the enol has two additional H-bonds with O-O distances of 2.49?. Conversion into the enol form occurs spontaneously in the solid state upon prolonged storage of the commercial tri-keto material. Slurry conversion of tri-one to enol in ethanol is reversed in direction in ethanol-D1.
Prebiotic Origin of Pre-RNA Building Blocks in a Urea “Warm Little Pond” Scenario
Menor Salván,Bouza, Marcos,Fialho, David M.,Burcar, Bradley T.,Fernández, Facundo M.,Hud, Nicholas V.
, p. 3504 - 3510 (2020/10/02)
Urea appears to be a key intermediate of important prebiotic synthetic pathways. Concentrated pools of urea likely existed on the surface of the early Earth, as urea is synthesized in significant quantities from hydrogen cyanide or cyanamide (widely accepted prebiotic molecules), it has extremely high water solubility, and it can concentrate to form eutectics from aqueous solutions. We propose a model for the origin of a variety of canonical and non-canonical nucleobases, including some known to form supramolecular assemblies that contain Watson-Crick-like base pairs.The dual nucleophilic-electrophilic character of urea makes it an ideal precursor for the formation of nitrogenous heterocycles. We propose a model for the origin of a variety of canonical and noncanonical nucleobases, including some known to form supramolecular assemblies that contain Watson-Crick-like base pairs. These reactions involve urea condensation with other prebiotic molecules (e. g., malonic acid) that could be driven by environmental cycles (e. g., freezing/thawing, drying/wetting). The resulting heterocycle assemblies are compatible with the formation of nucleosides and, possibly, the chemical evolution of molecular precursors to RNA. We show that urea eutectics at moderate temperature represent a robust prebiotic source of nitrogenous heterocycles. The simplicity of these pathways, and their independence from specific or rare geological events, support the idea of urea being of fundamental importance to the prebiotic chemistry that gave rise to life on Earth.
Ultrasound-assisted rapid synthesis of 2-aminopyrimidine and barbituric acid derivatives
Bayramo?lu, Duygu,Kurtay, Gülbin,Güllü, Mustafa
, p. 649 - 658 (2020/02/11)
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.
Design and synthesis of some barbituric and 1,3-dimethylbarbituric acid derivatives: A non-classical scaffold for potential PARP1 inhibitors
Eldin A. Osman, Essam,Hanafy, Noura S.,George, Riham F.,El-Moghazy, Samir M.
, (2020/09/16)
Six series based on barbituric acid 5a-e, 10a-d; thiobarbituric acid 6a-e, 11a-d and 1,3-dimethylbarbituric acid 7a-e, 12a-d were prepared and screened for their in vitro PARP1 inhibition. They revealed promising inhibition at nanomolar level especially compounds 5c, 7b, 7d and 7e (IC50 = 30.51, 41.60, 41.53 and 36.33 nM) with higher potency than olaparib (IC50 = 43.59 nM). Moreover, compounds 5b, 5d, 7a, 12a and 12c exhibited good comparable activity (IC50 = 65.93, 58.90, 66.57, 45.40 and 50.62 nM, respectively). Furthermore, the most active compounds 5c, 7b, 7d, 7e, 12a and 12c against PARP1 in vitro were evaluated in the BRCA1 mutated triple negative breast cancer cell line MDA-MB-436 where 5c and 12c showed higher potency compared to olaparib and result in cell cycle arrest at G2/M phase. 5c and 12c showed apoptotic effects in MDA-MB-436 and potentiated the cytotoxicity of temozolomide in A549 human lung epithelial cancer cell line. Compounds 5c and 12c represent interesting starting points towards PARP1 inhibitors.
Oxidation of Thioamides to Amides with Tetrachloro- and Tetrabromoglycolurils
Arrous, S.,Boudebouz, I.,Parunov, I. V.
, p. 1874 - 1877 (2020/02/03)
Tetrabromo- and tetrachloroglycolurils have been shown to act as good oxidants capable of converting thioamides to the corresponding amides. This approach offers such advantages as good yields (81–99%), short reaction times (10–25 min), simple workup procedure, and environmental safety.
A compound and its preparation and use (by machine translation)
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Paragraph 0091; 0092; 0093; 0095; 0102; 0104; 0111; 0113, (2018/03/25)
The present invention discloses a structure of the formula X compound or its pharmaceutically acceptable salt and its preparation and use: Wherein R1 is at least comprises a five-membered ring or a six-membered ring of chemical structure; R2 is a molecular weight greater than 100 and chemical structure containing electron-withdrawing group. (by machine translation)
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
Azarifar, Davood,Golbaghi, Maryam
, p. 1 - 13 (2016/02/12)
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.
Site-Selective Synthesis of 15N- and 13C-Enriched Flavin Mononucleotide Coenzyme Isotopologues
Neti, Syam Sundar,Poulter, C. Dale
, p. 5087 - 5092 (2016/07/06)
Flavin mononucleotide (FMN) is a coenzyme for numerous proteins involved in key cellular and physiological processes. Isotopically labeled flavin is a powerful tool for studying the structure and mechanism of flavoenzyme-catalyzed reactions by a variety of techniques, including NMR, IR, Raman, and mass spectrometry. In this report, we describe the preparation of labeled FMN isotopologues enriched with 15N and 13C isotopes at various sites in the pyrazine and pyrimidine rings of the isoalloxazine core of the cofactor from readily available precursors by a five-step chemo-enzymatic synthesis.
Organocatalyzed and uncatalyzed C=C/C=C and C=C/C=N exchange processes between knoevenagel and imine compounds in dynamic covalent chemistry
Kulchat, Sirinan,Meguellati, Kamel,Lehn, Jean-Marie
, p. 1219 - 1236 (2015/04/14)
Molecular diversity generation through reversible component exchange has acquired great importance in the last decade with the development of dynamic covalent chemistry. We explore here the recombination of components linked by C=C and C=N bonds through reversible double-bond formation, and cleavage in C=C/C=C and C=C/C=N exchange processes. The reversibility of the Knoevenagel reaction has been explored, and C=C/C=C C/C exchanges have been achieved among different benzylidenes, under organocatalysis by secondary amines such as L-proline. The substituents of these benzylidenes were shown to play a very important role in the kinetics of the exchange reactions. L-Proline is also used to catalyze the reversible C=C/C=C exchange between Knoevenagel derivatives of barbituric acid and malononitrile. Finally, the interconversion between Knoevenagel derivatives of dimethylbarbituric acid and imines (C=C/C=N exchange) has been studied and was found to occur rapidly in the absence of catalyst. The results of this study pave the way for the extension of dynamic combinatorial chemistry based on C=C/C=C and C=C/C=N exchange systems.
FeCl3·6H2O catalyzed aqueous media domino synthesis of 5-monoalkylbarbiturates: Water as both reactant and solvent
Kalita, Subarna Jyoti,Mecadon, Hormi,Deka, Dibakar C.
, p. 10402 - 10411 (2014/03/21)
A novel, simple and straightforward route to 5-monoalkylbarbiturates by FeCl3·6H2O catalyzed domino reactions of 6-aminouracils, water and α,β-unsaturated ketones, where water plays a key dual role as both reactant and solvent, is described. Significantly, all the reactions efficiently furnished exclusively 5-monoalkylbarbiturates and not pyrido[2,3-d]pyrimidines as generally produced from the reactions of 6-aminouracils and α,β-unsaturated carbonyls.
