Pyrimidines

Diaz, E. published the artcile2D NMR studies of the structures of the stereoselective adducts of the dehydrocostus lactone with pyrimidine derivatives, Formula: C7H10N2O2, the main research area is dehydrocostus lactone pyrimidine adduct NMR.

Anal. of 1H-1H n.O.e. effects observed for the adducts (I) (X = O, S; Y = O, NH2; Z = H, Me, F, Br, Pr, OMe), (II) and (III) on C-13 (10-18) of dehydrocostus lactone and different pyrimidine derivatives showed that H-7 and H-11 protons are in trans position. The NOESY cross peaks anal. and x-ray mol. structure of adduct I (X = Y =O, Z = H) are in excellent agreement with the exptl. data. Complete assignments of the 13C signals of some adducts based on 1D and 2D 1H and 13C NMR techniques are reported.

Spectroscopy Letters published new progress about NMR (nuclear magnetic resonance). 19030-75-2 belongs to class pyrimidines, name is 5-N-Propyluracil, and the molecular formula is C7H10N2O2, Formula: C7H10N2O2.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Csarnyi, A. H. published the artcileSeparation of 5-alkyluracils and purine bases in hydrolyzates of enzymically synthesized nucleic acids by high-performance ion-pair liquid chromatography, Name: 5-N-Propyluracil, the main research area is DNA alkyluracil purine base chromatog; high performance ion pair chromatog alkyluracil.

Reversed-phase and reversed-phase ion-pair chromatog. methods were used to determine 5-alkyluracils in the presence of purine bases (mainly adenine) in the hydrolyzates of enzymically synthesized DNA. For the reversed-phase separations, a Hypersil ODS column was used with a 2-step gradient of 0.01M KH2PO4 (pH 5.5) in 80% MeOH. The eluate was monitored at 260 nm. For the ion-pair separations, octyl sulfate was the counter-ion and the solvent composition and pH varied. The effect of ionic strength, pH, and concentration of the ion-pairing agent and MeOH on the selectivity between alkyluracils and purine bases was examined in order to simplify the routine work and to reduce the time necessary for anal. Optimal conditions could be developed for the isocratic separation of the various mixtures obtained by hydrolysis of the products of enzymic synthesis.

Journal of Chromatography published new progress about DNA Role: BIOL (Biological Study). 19030-75-2 belongs to class pyrimidines, name is 5-N-Propyluracil, and the molecular formula is C7H10N2O2, Name: 5-N-Propyluracil.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Kolar, Michal published the artcileThe strength and directionality of a halogen bond are co-determined by the magnitude and size of the σ-hole, Synthetic Route of 38275-56-8, the main research area is halogen bond strength directionality sigma hole magnitude size effect.

The σ-holes of halogen atoms on various aromatic scaffolds were described in terms of their size and magnitude. The electrostatic potential maps at the CAM-B3LYP-D3(bj)/def2-QZVP level were calculated and the σ-holes of >100 aromatic analogs were thoroughly analyzed to relate the σ-holes to the binding preferences of the halogenated compounds Both the size and magnitude of the σ-hole increase when passing from chlorinated to iodinated analogs. Also, the σ-hole properties were studied upon chem. substitution of the aromatic ring as well as in the aromatic ring. Further, the angular variations of the interactions were studied on a selected set of halogenbenzene complexes with argon and hydrogen fluoride (HF). To analyze interaction energy components, DFT-SAPT angular scans were performed. The interaction energies of bromobenzene complexes were evaluated at the CCSD(T)/complete basis set level providing the benchmark energetic data. The strength of the halogen bond between halogenbenzenes and Ar atoms and HF mols. increases while its directionality decreases when passing from chlorine to iodine. The decrease of the directionality of the halogen bond is larger for a HF-containing complex and is caused by electrostatic and exchange-repulsion energies. These findings are especially valuable for protein-halogenated ligand-binding studies, applied in the realm of rational drug development and lead optimization.

Physical Chemistry Chemical Physics published new progress about Aryl halides Role: PRP (Properties). 38275-56-8 belongs to class pyrimidines, name is 5-Chloropyrimidine-2-carbonitrile, and the molecular formula is C5H2ClN3, Synthetic Route of 38275-56-8.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Regan, Collin F. published the artcileA facile synthesis of 5-halopyrimidine-4-carboxylic acid esters via a Minisci reaction, SDS of cas: 74840-38-3, the main research area is Minisci homolytic alkoxycarbonylation halopyrimidine; bromopyrimidinecarboxylate; pyrimidine halo Minisci homolytic alkoxycarbonylation.

This paper reports the synthesis of various 5-halopyrimidine-4-carboxylic acid esters via the Minisci homolytic alkoxycarbonylation of 5-halopyrimidines. The reaction was found to be highly regioselective, allowing the one-step synthesis of useful amounts (>10 g) of Et 5-bromopyrimidine-4-carboxylate where other methods proved difficult. Et 5-bromopyrimidine-4-carboxylate was used for the preparation of potent CK2 inhibitors including CX-5011. This work represents an interesting application of radical chem. for the preparation of pharmacol. active mols.

Synlett published new progress about Alkoxycarbonylation (Minisci homolytic). 74840-38-3 belongs to class pyrimidines, name is Ethyl 5-bromo-2-(methylthio)pyrimidine-4-carboxylate, and the molecular formula is C8H9BrN2O2S, SDS of cas: 74840-38-3.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Stathakis, Christos I. published the artcile(Chloromethyl)dimethylchlorosilane-KF: A Two-Step Solution to the Selectivity Problem in the Methylation of a Pyrimidone Intermediate en Route to Raltegravir, Application of Benzyl (2-(4-((4-fluorobenzyl)carbamoyl)-5-hydroxy-6-oxo-1,6-dihydropyrimidin-2-yl)propan-2-yl)carbamate, the main research area is chloromethyldimethylchlorosilane silylation potassium fluoride desilylation pyrimidone methylation raltegravir synthesis.

The present work describes a two-step process, namely, silylation with (chloromethyl)dimethylchlorosilane and desilylation, to address the selectivity problem in the N-methylation of a pyrimidone intermediate toward the synthesis of the raltegravir active pharmaceutical ingredient [treatment of I with HMDS/(ClCH2)SiMe2Cl, then 4-fluorobenzylamine followed by KF afforded II (75-80%)]. The said methodol. delivers the desired drug substance in which the O-methylated impurity content is below the detection limit by high-performance liquid chromatog. anal. Moreover, this two-step, one-pot procedure provides an apparent advantage in terms of environmental impact with respect to the optimum approach described in the literature, while it compares equally well in terms of cost and operational simplicity.

Organic Process Research & Development published new progress about Chemoselectivity (chemoselective methylation). 519028-33-2 belongs to class pyrimidines, name is Benzyl (2-(4-((4-fluorobenzyl)carbamoyl)-5-hydroxy-6-oxo-1,6-dihydropyrimidin-2-yl)propan-2-yl)carbamate, and the molecular formula is C23H23FN4O5, Application of Benzyl (2-(4-((4-fluorobenzyl)carbamoyl)-5-hydroxy-6-oxo-1,6-dihydropyrimidin-2-yl)propan-2-yl)carbamate.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Krivokapic, Andre published the artcilePrimary oxidation products of 5-methylcytosine: methyl dynamics and environmental influences, Category: pyrimidines, the main research area is radiolytic oxidation methylcytosine ESR ENDOR methyl group tunneling rotation.

The primary oxidation product in X-irradiated single crystals of 5-methylcytosine hemihydrate and 5-methylcytosine hydrochloride has been studied at 10 K, using ESR, electron-nuclear double resonance (ENDOR), and ENDOR-induced EPR (EIE) spectroscopies. The radical is characterized by large couplings to the Me protons and appears to be deprotonated at N1 in both crystal systems. In the hydrochloride crystal the Me group is completely frozen at 10 K, whereas in the hemihydrate crystal it undergoes tunneling rotation. For the hemihydrate crystal, four ENDOR lines associated with transitions within the A and E rotational states were followed in three planes of rotation. Large ENDOR shifts as measured by saturation of the high- and low-field parts of the EPR spectrum indicate that the rotation is rather slow. Sidebands due to mixing of A and E rotational states are expected for slow rotation and were observed in both the EPR and the EIE spectra. The ENDOR shifts and the sideband frequencies indicate a tunneling splitting between 40 and 60 MHz. Estimates of the barrier to rotation in both crystalline systems were calculated using cluster and single-mol. d. functional theory methods, and the results are consistent with those obtained by anal. of the exptl. results.

Journal of Physical Chemistry A published new progress about Electron spin density (of radiolysis products). 58366-64-6 belongs to class pyrimidines, name is 5-Methylcytosinehydrochloride, and the molecular formula is C5H8ClN3O, Category: pyrimidines.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Looper, Ryan E. published the artcileSyntheses of the cylindrospermopsin alkaloids, HPLC of Formula: 36847-11-7, the main research area is cylindrospermopsin alkaloid asym synthesis intramol dipolar cycloaddition; nitro aldol addition cylindrospermopsin alkaloid asym synthesis; reductive guanidinylation cylindrospermopsin alkaloid asym synthesis.

An intramol. 1,3-dipolar cycloaddition has efficiently constructed the A-ring portions of the cylindrospermopsin alkaloids. A nitro-aldol addition of an elaborated nitroalkane to a pyrimidine aldehyde followed by an intramol. reductive guanidinylation has enabled the syntheses of all three alkaloids in this family in 18-19 steps. The first asym. synthesis of cylindrospermopsin (I), unambiguously assigning its absolute configuration, was reported.

Tetrahedron published new progress about 1,3-Dipolar cycloaddition reaction, intramolecular. 36847-11-7 belongs to class pyrimidines, name is 2,4,6-Tribromopyrimidine, and the molecular formula is C4HBr3N2, HPLC of Formula: 36847-11-7.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

White, James D. published the artcileTotal Synthesis of (-)-7-Epicylindrospermopsin, a Toxic Metabolite of the Freshwater Cyanobacterium Aphanizomenon ovalisporum, and Assignment of Its Absolute Configuration, Computed Properties of 36847-11-7, the main research area is epicylindrospermopsin total synthesis absolute configuration.

The Z and E nitrones II, prepared from condensation of the corresponding aldehyde and hydroxylamine, underwent intramol. dipolar cycloaddition to give substituted 1-aza-7-oxobicyclo[2.2.1] heptanes. Reductive N-O bond cleavage followed by carbonylation gave the cyclic urea in which inversion of the secondary alc. was effected via an oxidation-reduction sequence. After conversion of the p-bromobenzyl ether to the azide, activation of the cyclic urea as its O-methylisourea and reduction of the azide led to spontaneous cyclization to afford the tricyclic nucleus of cylindrospermopsin. Global deprotection, including hydrolysis of the 2,4-dimethoxypyrimidine appendage to a uracil, and then monosulfation of the resultant diol afforded a substance identical with natural (-)-7-epicylindrospermopsin (I). The asym. synthesis of (-)-7-epicylindrospermopsin defines its absolute configuration as 7S,8R,10S,12S,13R,14S.

Journal of Organic Chemistry published new progress about 1,3-Dipolar cycloaddition reaction, stereoselective. 36847-11-7 belongs to class pyrimidines, name is 2,4,6-Tribromopyrimidine, and the molecular formula is C4HBr3N2, Computed Properties of 36847-11-7.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Brumfield, Martha A. published the artcileTwo triplets mediating intramolecular photochemical abstraction of hydrogen by nitrogen in 4-acyl-6-alkylpyrimidines, Recommanded Product: 1-(6-Methylpyrimidin-4-yl)ethanone, the main research area is photocyclization acylalkylpyrimidine; intramol photochem hydrogen abstraction acylalkylpyrimidine; triplet state hydrogen abstraction acylaklylpyrimidine; pyrimidine acylalkyl triplet photochem.

Direct irradiation with λ >340 nm of 4-acyl-6-alkylpyrimidines I (R = Me) and II (R = CH2CH2CHMe2) or their triplet sensitization by aromatic ketones leads to an nπ* triplet (ET ∼70-71 kcal/mol). In I (R = Me) this state is responsible for hydrogen abstraction from the C(4) side chain and isomerization to cyclopropanol III. Ketone II (R = CH2CH2CHMe2) does not fragment under either of these direct or sensitized conditions. However, triplet sensitization of II (R = CH2CH2CHMe2) by acetone (ET ∼79-82 kcal/mol) or direct irradiation of II (R = CH2CH2CHMe2) through Vycor, λ > 200 nm, leads to hydrogen abstraction, cleavage of the C(6) side chain, and formation of II (R = Me) in a reaction occurring from an upper nπ* triplet (ET ∼79-84 kcal/mol). Ketone I (R = CH2CH2CHMe2) yields mainly IV and, depending upon conditions, a small amount of I (R = Me) or III; the minor products arise by a novel monophotonic pathway.

Journal of the American Chemical Society published new progress about Photoabstraction reaction, intramolecular photoabstraction. 67073-96-5 belongs to class pyrimidines, name is 1-(6-Methylpyrimidin-4-yl)ethanone, and the molecular formula is C7H8N2O, Recommanded Product: 1-(6-Methylpyrimidin-4-yl)ethanone.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Klumpp, Douglas A. published the artcileElectrophilic activation of acetyl-substituted heteroaromatic compounds, Computed Properties of 66373-25-9, the main research area is electrophilic activation condensation benzene heteroaromatic compound; superacid mediated condensation heteroaromatic methyl ketone benzene.

The chem. of acetyl-substituted pyridines, thiazoles, quinoline, isoquinolines, and pyrazine, e.g., thiazole I, has been studied. These heteroarenes condense with benzene in good yields (74-96%) in the Bronsted superacid, CF3SO3H (triflic acid). Thus, reaction of I gave diphenylthiazole II in 91% yield. In these acid-catalyzed hydroxyalkylation reactions, the heteroarene compounds are significantly more reactive than acetophenone. It is proposed that the heteroarene compounds readily form dicationic electrophiles in triflic acid.

Journal of Organic Chemistry published new progress about Aryl ketones Role: RCT (Reactant), RACT (Reactant or Reagent). 66373-25-9 belongs to class pyrimidines, name is 1-(2-Amino-4-methylpyrimidin-5-yl)ethanone, and the molecular formula is C7H9N3O, Computed Properties of 66373-25-9.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia