Month: November 2022

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

Wei, Xiao-Jing published the artcileVisible-Light-Promoted Iron-Catalyzed C(sp2)-C(sp3) Kumada Cross-Coupling in Flow, Formula: C5H5ClN2S, the main research area is Kumada cross coupling aryl chloride Grignard reagent iron catalyst; visible light Kumada cross coupling iron catalyst mechanism flow; Kumada coupling; cross-coupling; flow chemistry; iron catalysis; photocatalysis.

A continuous-flow, visible-light-promoted method has been developed to overcome the limitations of iron-catalyzed Kumada-Corriu cross-coupling reactions. A variety of strongly electron rich aryl chlorides, previously hardly reactive, could be efficiently coupled with aliphatic Grignard reagents at room temperature in high yields and within a few minutes’ residence time, considerably enhancing the applicability of this iron-catalyzed reaction. The robustness of this protocol was demonstrated on a multigram scale, thus providing the potential for future pharmaceutical application. The mechanism was studied using radical clock experiments, kinetic measurements, DFT and other techniques.

Angewandte Chemie, International Edition published new progress about Aryl chlorides Role: RCT (Reactant), RACT (Reactant or Reagent). 38275-42-2 belongs to class pyrimidines, name is 5-Chloro-2-(methylthio)pyrimidine, and the molecular formula is C5H5ClN2S, Formula: C5H5ClN2S.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Li, Yanjun published the artcileOrganophotocatalytic selective deuterodehalogenation of aryl or alkyl chlorides, Application In Synthesis of 439692-55-4, the main research area is deuterated aryl heteroaryl compound green preparation; aryl chloride alkyl organophotocatalyst selective deuterodehalogenation.

A photocatalytic system consisting of an aryl-amine photocatalyst and a disulfide co-catalyst in the presence of sodium formate as an electron and hydrogen donor was developed. Accordingly, many aryl chlorides, alkyl chlorides, and other halides were converted to deuterated products at room temperature in air (>90 examples, up to 99% D-incorporation). The mechanistic studies revealed that the aryl amine served as reducing photoredox catalyst to initiate cleavage of the C-Cl bond, at the same time as energy transfer catalyst to induce homolysis of the disulfide for consequent deuterium transfer process. This economic and environmentally-friendly method could be used for site-selective D-labeling of a number of bioactive mols. and direct H/D exchange of some drug mols.

Nature Communications published new progress about Acid chlorides Role: RCT (Reactant), RACT (Reactant or Reagent). 439692-55-4 belongs to class pyrimidines, name is Thieno[2,3-d]pyrimidine, 4-chloro-6-(1,1-dimethylethyl)-, and the molecular formula is C10H11ClN2S, Application In Synthesis of 439692-55-4.

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Rezaei, Saghar published the artcileMono- and multifold C-C coupling reactions catalyzed by a palladium complex encapsulated in MIL-Cr as a three dimensional nano reactor, Computed Properties of 36847-11-7, the main research area is phenylboronic acid halobenzene chromium MOF encapsulated palladium Suzuki reaction; biaryl preparation green chem; styrene halobenzene chromium MOF encapsulated palladium Heck reaction; styrylbenzene preparation green chem; reusable chromium MOF encapsulated palladium complex catalyst preparation.

The organic palladium complex (trans-dichlorobis(4-iodoaniline-κN)palladium(II)) was encapsulated into a porous metal-organic framework MIL-Cr (Pd complex@MIL-Cr) using ship-in-a-bottle strategy. The novel catalyst as a three dimensional nanoreactor was fully characterized using different techniques such as XRD, BET, XPS, SEM, EDX, TEM and ICP. The Pd complex@MIL-Cr was isostructural to the parent MIL-Cr framework, with a high surface area and pore volume of ca. 1418 m2 g-1 and 0.87 cm3 g-1, resp. The nanoreactor was highly efficient in the catalytic conversion of aryl halides, showing extraordinarily higher activity than the homogeneous Pd counterparts. Surprisingly, high yields were achieved in Suzuki-Miyaura and Heck coupling reactions of chloroarenes bearing a wide range of substituents. Besides, this protocol could be extended to the cross-couplings of 2-bromo and 2,6-dibromopyridine with arylboronic acids in excellent yields at room temperature The Pd complex@MIL-Cr was also used as an efficient and convenient catalyst for the preparation of a series of C3-sym. mols. with benzene, pyridine or pyrimidine units as the central core. Moreover, the catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity. Investigation of the nature of the recovered catalyst showed that the catalyst was converted to Pd nanoparticles.

RSC Advances published new progress about Aryl alkenes Role: SPN (Synthetic Preparation), PREP (Preparation). 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