Day: November 21, 2022

Gallup, Gordon A. published the artcileVibrational Feshbach resonances in dissociative electron attachment to uracil, Recommanded Product: 3-Methylpyrimidine-2,4(1H,3H)-dione, the publication is Physical Review A: Atomic, Molecular, and Optical Physics (2011), 83(1), 012706/1-012706/7, database is CAplus.

Low-energy dissociative electron attachment to uracil mols. in the gas phase is partly controlled by interaction between the lowest σ* resonance with a dipole-supported anion state. We calculate this contribution using a combination of the finite element discrete model with the resonance R-matrix theory. Deuterated uracil is investigated, also, and a strong isotope effect is found. The results agree qual. and semiquant. with exptl. data, but for a complete description of the process the interaction between a second N-H bond σ* resonance in the mol. and the second p* resonance should be included.

Physical Review A: Atomic, Molecular, and Optical Physics published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, Recommanded Product: 3-Methylpyrimidine-2,4(1H,3H)-dione.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Rezk, Mamdouh R published the artcileChromatographic Methods for the Determination of Aminexil, Pyridoxine, and Niacinamide in a Novel Cosmetic Hair Preparation., SDS of cas: 74638-76-9, the publication is Journal of AOAC International (2020), 103(4), 1167-1172, database is MEDLINE.

BACKGROUND: Aminexil, a new compound patented by L’Oreal, has a stimulating effect on human keratin fibers. Pyridoxine HCl and niacinamide are added to boost the hair tonic effect of aminexil. OBJECTIVE: Two novel chromatographic methods were developed for the determination of aminexil (AX), niacinamide (NA) and pyridoxine HCl (PD) in the novel hair tonic preparation. METHODS: The developed methods were high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC) with densitometric determination. Different experimental parameters were investigated and optimized to achieve complete baseline separation and well resolved peaks. The RP-HPLC separation was achieved using a Thermoscientific BDS hypersil C18 (250 × 4.6 mm, 5 µm) column using 0.005 M hexane sulfonic acid: methanol (80: 20, v/v) as a mobile phase. For the TLC method, the three analytes were partitioned between propanol: toluene: ammonia solution (40:60:2, v/v/v) and fluorescent silica plates. The two methods were validated in compliance with International Conference on Harmonization (ICH) guidelines. The obtained data were statistically analyzed to confirm the existing results. The developed methods were successfully applied for determination of the studied drugs in pure forms and in the cosmetic preparation. RESULTS: For the HPLC method, the RSDs of AX, NA and PD were 0.70, 0.88 and 1.17 respectively. For the TLC method, the RSDs of AX, NA and PD were 1.06, 1.37 and 0.73 respectively. CONCLUSIONS: The proposed chromatographic methods showed high sensitivity and selectivity for the three compounds under analysis in the laboratory prepared mixture and in the hair tonic preparation. HIGHLIGHTS: Aminexil, Pyridoxine, Niacinamide, HPLC. The present work offers two reproducible, accurate, validated, time and cost saving alternatives for the quantitative and qualitative determination of medicated hair preparation.

Journal of AOAC International published new progress about 74638-76-9. 74638-76-9 belongs to pyrimidines, auxiliary class Pyrimidine, name is 2,4-Diaminopyrimidine-3-oxide, and the molecular formula is C4H6N4O, SDS of cas: 74638-76-9.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Kratochvil, Martin published the artcileMethylated uracil dimers: potential energy and free energy surfaces, Related Products of pyrimidines, the publication is Physical Chemistry Chemical Physics (2000), 2(10), 2419-2424, database is CAplus.

Theor. anal. of the formation of 1-methyluracil, 3-methyluracil and 1,3-dimethyluracil dimers was performed. Stabilization energies of these dimers were evaluated with the Cornell et al. force field (J. Am. chem. Soc., 1995, 117, 5179). In total 16, 13 and 15 energy min. were studied for the 3 dimers. Thermodn. data were obtained with the rigid rotor-harmonic oscillator-ideal gas approximation Also, populations of various structures were determined by mol. dynamic simulations in the NVE microcanonical ensemble and numerical evaluation of the configuration integrals in the NVT canonical ensemble. The potential energy surfaces (PESs) and the free energy surfaces (FESs) of these dimers differ. The largest difference was found for the 1-methyluracil dimer where the global and 1st local min. on the PES and FES do not coincide.

Physical Chemistry Chemical Physics published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, Related Products of pyrimidines.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Schultes, Sabine published the artcileCombining Quantum Mechanical Ligand Conformation Analysis and Protein Modeling to Elucidate GPCR-Ligand Binding Modes, HPLC of Formula: 56-05-3, the publication is ChemMedChem (2013), 8(1), 49-53, database is CAplus and MEDLINE.

2-Aminopyrimidine ligands with flexible and rigid side chains was synthesized to investigate the role of ligand conformation in H₄R ligand binding. The ligand binding conformations and orientations in the H₄R binding pocket was elucidated. The combined ligand- and protein-ligand modeling method can be used as a general approach to investigate the binding modes of flexible side chains of ligands with other protein targets.

ChemMedChem published new progress about 56-05-3. 56-05-3 belongs to pyrimidines, auxiliary class Pyrimidine,Chloride,Amine,API, name is 2-Amino-4,6-dichloropyrimidine, and the molecular formula is C25H29N9O3, HPLC of Formula: 56-05-3.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Notario, Rafael published the artcileThermochemistry of Uracils. Experimental and Computational Enthalpies of Formation of 5,6-Dimethyl-, 1,3,5-Trimethyl-, and 1,3,5,6-Tetramethyluracils, Application In Synthesis of 608-34-4, the publication is Journal of Physical Chemistry A (2013), 117(1), 244-251, database is CAplus and MEDLINE.

An exptl. and computational study of three methylated uracils, in particular, the 5,6-dimethyl-, 1,3,5-trimethyl-, and 1,3,5,6-tetra-Me derivatives are presented. The values of the standard (p⁰ = 0.1 MPa) molar enthalpies of formation in the gas phase at T = 298.15 K have been determined The energies of combustion were measured by static bomb combustion calorimetry, and from the results obtained, the standard molar enthalpies of formation in the crystalline state at T = 298.15 K were calculated The enthalpies of sublimation were determined using the transpiration method in a saturated N₂ stream. Values of -(376.2 ± 2.6), -(355.9 ± 3.0), and -(381.7 ± 2.8) kJ·mol^-1 for the gas-phase enthalpies of formation at T = 298.15 K of 5,6-dimethyluracil, 1,3,5-trimethyluracil, and 1,3,5,6-tetramethyluracil, resp., were obtained from the exptl. thermochem. study. An extended theor. study with the G3 and the G4 quantum-chem. methods has been carried out for all the possible methylated uracils. There is very good agreement between exptl. and calculated enthalpies of formation for the three derivatives studied. A Free-Wilson anal. on G4-calculated enthalpies of formation has been carried out, and the contribution of methylation in the different positions of the uracil ring has been estimated

Journal of Physical Chemistry A published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, Application In Synthesis of 608-34-4.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Brun, Omar published the artcileOn-Resin Conjugation of Diene-Polyamides and Maleimides via Diels-Alder Cycloaddition, COA of Formula: C39H35N5O8, the publication is Journal of Organic Chemistry (2015), 80(12), 6093-6101, database is CAplus and MEDLINE.

The reaction between maleimides and resin-bound diene-polyamides (polyamides are represented by peptides and peptide nucleic acids or PNAs) allows the latter to be used in the preparation of conjugates. Conjugation takes place by reacting the insoluble, hydrophobic diene component either with water-soluble dienophiles or with dienophiles requiring mixtures of water and organic solvents. Exptl. conditions can be adjusted to furnish the target conjugate in good yield with no need of adding large excesses of soluble reagent. In case protected maleimides are used, maleimide deprotection and Diels-Alder cycloaddition can be simultaneously carried out to render conjugates with different linking positions. On-resin conjugation is followed by an acidic treatment that removes the polyamide protecting groups with no harm to the cycloadduct, in contrast with the unreacted diene that is indeed degraded under these conditions. Cycloadducts incorporating suitable functional groups can undergo subsequent addnl. conjugation reactions in solution to furnish double conjugates.

Journal of Organic Chemistry published new progress about 186046-81-1. 186046-81-1 belongs to pyrimidines, auxiliary class Pyrimidine,Carboxylic acid,Amine,Benzene,Amide,Others,PNA,, name is 2-(N-(2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)ethyl)-2-(4-(((benzhydryloxy)carbonyl)amino)-2-oxopyrimidin-1(2H)-yl)acetamido)acetic acid, and the molecular formula is C39H35N5O8, COA of Formula: C39H35N5O8.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Brun, Omar published the artcileOn-Resin Conjugation of Diene-Polyamides and Maleimides via Diels-Alder Cycloaddition, Synthetic Route of 169396-92-3, the publication is Journal of Organic Chemistry (2015), 80(12), 6093-6101, database is CAplus and MEDLINE.

The reaction between maleimides and resin-bound diene-polyamides (polyamides are represented by peptides and peptide nucleic acids or PNAs) allows the latter to be used in the preparation of conjugates. Conjugation takes place by reacting the insoluble, hydrophobic diene component either with water-soluble dienophiles or with dienophiles requiring mixtures of water and organic solvents. Exptl. conditions can be adjusted to furnish the target conjugate in good yield with no need of adding large excesses of soluble reagent. In case protected maleimides are used, maleimide deprotection and Diels-Alder cycloaddition can be simultaneously carried out to render conjugates with different linking positions. On-resin conjugation is followed by an acidic treatment that removes the polyamide protecting groups with no harm to the cycloadduct, in contrast with the unreacted diene that is indeed degraded under these conditions. Cycloadducts incorporating suitable functional groups can undergo subsequent addnl. conjugation reactions in solution to furnish double conjugates.

Journal of Organic Chemistry published new progress about 169396-92-3. 169396-92-3 belongs to pyrimidines, auxiliary class Pyrimidine,Carboxylic acid,Amine,Amide,Others,PNA, name is 2-(N-(2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)ethyl)-2-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamido)acetic acid, and the molecular formula is C26H26N4O7, Synthetic Route of 169396-92-3.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Javaid, Z. Z. published the artcilePyrimidine nucleobase ligands of orotate phosphoribosyltransferase from Toxoplasma gondii, SDS of cas: 608-34-4, the publication is Biochemical Pharmacology (1999), 58(9), 1457-1466, database is CAplus and MEDLINE.

Sixty-seven pyrimidine nucleobase analogs were evaluated as ligands of Toxoplasma gondii orotate phosphoribosyltransferase (OPRTase, EC 2.4.2.10) by measuring their ability to inhibit this enzyme in vitro. Apparent Ki values were determined for compounds that inhibited T. gondii OPRTase by greater than 20% at a concentration of 400 μM. 1-Deazaorotic acid (0.47 μM) and 5-azaorotic acid (2.1 μM) were found to bind better (8.3- and 1.9-fold, resp.) to T. gondii OPRTase than orotic acid, the natural substrate of the enzyme. Based on these results, a structure-activity relationship of ligand binding to OPRTase was formulated using uracil, barbituric acid, and orotic acid as reference compounds It was concluded that the following structural features of pyrimidine nucleobase analogs were required or strongly preferred for binding: (i) an endocyclic pyridine-type nitrogen or methine at the 1-position; (ii) exocyclic oxo groups at the 2- and 4-positions; (iii) a protonated endocyclic pyridine-type nitrogen at the 3-position; (iv) an endocyclic pyridine-type nitrogen or methine at the 5-position; (v) an exocyclic hydrogen or fluorine at the 5-position; (vi) an endocyclic pyridine-type nitrogen or methine at the 6-position; and (vii) an exocyclic neg. charged or electron-withdrawing group at the 6-position. A comparison of the results from the present study with those from a previous study on mammalian OPRTase [Niedzwicki et al., Biochem Pharmacol 33: 2383-2395, 1984] identified four compounds (6-chlorouracil, 5-azaorotic acid, 1-deazaorotic acid, and 6-iodouracil) that may bind selectively to T. gondii OPRTase.

Biochemical Pharmacology published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, SDS of cas: 608-34-4.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Gerhardt, Valeska published the artcileCocrystals of 6-chlorouracil and 6-chloro-3-methyluracil: exploring their hydrogen-bond-based synthon motifs with several triazine and pyrimidine derivatives, SDS of cas: 608-34-4, the publication is Acta Crystallographica, Section B: Structural Science, Crystal Engineering and Materials (2015), 71(2), 209-220, database is CAplus and MEDLINE.

In order to obtain complexes held together by hydrogen as well as halogen bonds, 6-chlorouracil [6-chloropyrimidin-2,4(1H,3H)-dione; 6CU] and its 3-Me derivative [6-chloro-3-methylpyrimidin-2,4(1H,3H)-dione; M6CU] were cocrystd. with 2,4,6-triaminopyrimidine and the three triazine derivatives 2,4,6-triamino-1,3,5-triazine (melamine), 2,4-diamino-6-methyl-1,3,5-triazine and 2-chloro-4,6-diamino-1,3,5-triazine, which all offer complementary hydrogen-bonding sites. Three of these compounds form cocrystals with 6CU; however, melamine yielded only a new pseudopolymorph with 6CU, but formed a cocrystal with M6CU. All six cocrystals contain solvent mols. (N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidin-2-one), whose intermol. interactions contribute significantly to the stabilization of the crystal packing. Each of these structures comprises chains, which are primarily formed by strong hydrogen bonds with a basic framework built by R ₂ ²(8) hydrogen bonds of either pure N-H···N or mixed patterns. Solvent mols. are aligned to the border of these chains via N-H···O hydrogen bonds. Two of the reported crystal structures containing 6CU show addnl. Cl···O halogen bonds, which connect the chains to two-dimensional layers, while one weak and one strong Cl···Cl interaction are observed in the two structures in which mols. of M6CU are present.

Acta Crystallographica, Section B: Structural Science, Crystal Engineering and Materials published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, SDS of cas: 608-34-4.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia

Ackermann, H. published the artcileConstitution and reactivity of trichloropyrimidylamino derivatives, Category: pyrimidines, the publication is Helvetica Chimica Acta (1962), 1683-98, database is CAplus.

The treatment of 2,4,5,6-tetrachloropyrimidine (I) with NH₃, aliphatic, and aromatic amines resulted almost exclusively in reaction of the 4-Cl atom. The kinetics of the reaction of 2,5,6-trichloro-4-pyrimidylamino derivatives with NaOEt was studied. The derivatives from primary aromatic amines were found to be weak acids, which explained the relationship between constitution and reactivity satisfactorily. PhNH₂ (9.3 g.) in 50 cc. Me₂CO and 50 cc. H₂O heated at 35-40° with 21.8 g. I while maintaining pH 6-7 by the dropwise addition of 20% aqueous Na₂CO₃, heated briefly to 50°, and cooled to 0-5° yielded 86% 4-anilino-2,5,6-trichloropyrimidine (II), m. 83-4° (ligroine). Similarly were prepared the following 4-substituted-2,5,6-trichloropyrimidines (4-substituent, reaction temperature, and m.p. given): p-ClC₆H₄NH (III), 40-50°, 153° (ligroine); o-MeOC₆H₄NH, 40-50°, 183° (C₆H₆); MePhN (IV), 35-40°, 118° (AcOH); p-MeC₆H₄NH, 35-40°, 111° (ligroine); p-MeOC₆H₄NH (V), 35-40°, 129° (ligroine); o-MeC₆H₄NH, 40-50°, 139° (C₆H₆); o-ClC₆H₄NH, 4050°, 158° (C₆H₆); m-HO₃SC₆H₄NH (VI), 40-50%, – (precipitated with KNO₃ as the K salt); m-HO₂CC₆H₄NH, 40-50°, 246° (AcOH); p-O₂NC₆H₄NMe (VII), 85-90° (in aqueous dioxane), 210° (PhCl); p-HOC₆H₄NH (VIII), 30-40°, 112° (C₆H₆); o-HOC₆H₄NH, 40-50°, 216° (EtOH); p-MeO₂SC₆H₄NH (IX), 40-50°, 225° (PhCl); p-O₂NC₆H₄NH (X), 40-50°, 204° (MePh). II (27.5 g.) in 400 cc. concentrated NH₄OH heated 20 hrs. at 110-20° in an autoclave and cooled gave 2,6-diamino-4-anilino-5-chloropyrimidine (XI), m. 218° (MeOCH₂CH₂OH). XI (4.4 g.) in 150 cc. MeOH containing 4.4 g. NaOAc hydrogenated 3 days at room temperature and low pressure, filtered, neutralized with Na₂CO₃, concentrated, diluted with H₂O, and filtered gave 2,6-diamino-4-anilinopyrimidine, m. 177-8° (EtOH), also obtained from 2,4-diamino-6-chloropyrimidine and PhNH₂. BuNH₂ (7.3 g.) in 125 cc. Me₂CO and 125 cc. H₂O treated during 1 hr. at 30-5° with 21.8 g. I at pH 10-11 and extracted with Et₂O yielded 4-butylamino-2,5,6-trichloropyrimidine (XII), b₁₄ 187-8°, m. 62-5°. Similarly was prepared the 4-Et₂N analog (XIII) of XII, b₈ 174-5°, m. 50-1°; the forerun yielded a small amount of 2-diethylamino-4,5,6-trichloropyrimidine, b₈ 152-3°, m. 768°. I (21.8 g.) in 150 cc. concentrated NH₄OH stirred 2 hrs. at 80° and cooled gave 4-amino-2,5,6-trichloropyrimidine, m. 168° (PhCl). II (27.5 g.) in 100 cc. absolute EtOH treated dropwise with 4.0 g. KOH in 100 cc. EtOH, heated 2 hrs. at 70°, filtered, and cooled gave 4-anilino-2,5-dichloro5-ethoxypyrimidine (XIV), m. 124° (EtOH); the alc. mother liquor gave 4-anilino-5,6-dichloro-2-ethoxypyrimidine (XV), m. 66° (ligroine). 2,4-Dichloropyrimidine (14 g.) in 100 cc. Me₂CO and 100 cc. H₂O treated at 40-50° with 9.3 g. PhNH₂ at pH 6-7, cooled to 0-5°, filtered, the residue recrystallized from PhCl, refluxed 4 hrs. with 1 equivalent KOH in 200 cc. EtOH, diluted with H₂O, and filtered yielded 4-anilino-2-ethoxypyrimidine (XVI), m. 121-2° (ligroine). XV (2.84 g.) in 150 cc. absolute EtOH and 2.2 g. Et₃N hydrogenated 21 hrs. at room temperature over 5 g. Pd-C also yielded XVI. XIV gave similarly 4-anilino-6-ethoxypyrimidine, m. 122-3°. II (27.5 g.) and 4.6 g. Na in 200 cc. absolute EtOH refluxed 3 hrs. gave 4-anilino-5-chloro-2,6-diethoxypyrimidine, m. 131° (EtOH). The appropriate compound (6.23 × 10^-3 moles) in 400 cc. absolute EtOH treated at the desired temperature with 100 cc. 1.25N NaOH and the liberated chloride determined titrimetrically in 20-cc. aliquots gave the ks × 10⁵ values (determined at 30°) for the following compounds: 4-methylphenylamino-2,6-dichloro-1,3,5-triazine, above 1000; 4-methylphenylamino-2-amino-6-chloro-1,3,5-triazine, 17; 4-methylphenylamino-2,6-dichloropyrimidine, 9.3; IV, 310; VII, above 500; XIII, 31. The pK values were determined for the following compounds: VI (Na salt), 11.6; 4-(msulfanilino)-2,6-dichloropyrimidine (Na salt), 13.0; 4-(msulfanilino)-2,6-dichloro-1,3,5-triazine (Na salt), 11.2; 4-(m-sulfanilino)-2-amino-6-chloro-1,3,5-triazine (Na salt), 13.8. The ks × 10⁵ (at 30°), k₃ × 10⁴ (at 70°), and k₄ × 10⁴ (at 70°) values (given in this order) were determined in the usual manner for the following compounds: 2-anilino-4,6-dichloro-1,3,5-triazine, 350, -, -; 2-amino-4-anilino-6-chloro-1,3,5-triazine, 37, -, -; 4-anilino-2,6-dichloropyrimidine, 2.2, 0.38, 0.22; II, 1.3, 1.8, 1.2. The ks × 10⁵ (given) were determined at 70° in the usual manner for the following compounds: II, 41; VIII, 210; o-isomer of VIII, 170; V, 49; o-isomer of V, 180; III, 21; o-isomer of III, 15; IX, 6; X, about 5.M

Helvetica Chimica Acta published new progress about 31401-45-3. 31401-45-3 belongs to pyrimidines, auxiliary class Pyrimidine,Amine, name is N,N-Dimethylpyrimidin-4-amine, and the molecular formula is C6H9N3, Category: pyrimidines.

Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia