Month: November 2022

Meti, Puttavva published the artcileRegioselective synthesis of dipyrrolopyrazine (DPP) derivatives via metal free and metal catalyzed amination and investigation of their optical and thermal properties, Safety of 5-Bromo-3,6-dichloropyrazin-2-amine, the main research area is dipyrrolopyrazine derivative preparation regioselective; dihalo pyrrolopyrazine alkyne metal catalyst amination reaction.

An efficient methods for the synthesis of dipyrrolopyrazine derivatives, I [R1 = H, C6H5; R2 = C6H5, 4-F-C6H4, (CH3)2NC6H4, cyclopropyl, etc.] and II and pyrrolothieno-pyrazine derivatives, III (X = H, C6H5) that involve regioselective amination reactions of dihalo-pyrrolopyrazines IV [Y = H, CH3, 4-CH3C6H4S(O)2; A = Br; B = Cl] is reported. The developed protocol readily affords either 2-amino- or 3-amino-pyrrolopyrazines IV (A = Br, NHCH3; B = Cl, NHCH3) from the corresponding 2-bromo-3-chloro-5H-pyrrolo[2,3-b]pyrazines IV (A = Br; B = Cl). When the amination reactions was carried under metal-free microwave irradiation, 3-amino-pyrrolopyrazines IV (A = Br; B = NHCH3) was obtained exclusively. In contrast, Buchwald cross coupling of the 2-bromo-3-chloro-5H-pyrrolo[2,3-b]pyrazines IV (A = Br; B = Cl) affords only 2-amino-pyrrolopyrazine IV (A = NHCH3; B = Cl). The pyrrolopyrazine scaffolds was converted to the resp. 1,7- I and 1,5-dihydrodipyrrolo[2,3-b]pyrazines derivatives II using Sonogashira reactions. A comprehensive study of the optical properties, thermal properties, and mol. packing of the synthesized compounds was carried out. The results indicate that the 1,7-derivatives I may be promising organic materials for optoelectronic applications.

RSC Advances published new progress about Amination. 960510-36-5 belongs to class pyrazines, name is 5-Bromo-3,6-dichloropyrazin-2-amine, and the molecular formula is C4H2BrCl2N3, Safety of 5-Bromo-3,6-dichloropyrazin-2-amine.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Meti, Puttavva published the artcileRegioselective synthesis of dipyrrolopyrazine (DPP) derivatives via metal free and metal catalyzed amination and investigation of their optical and thermal properties, Computed Properties of 566205-01-4, the main research area is dipyrrolopyrazine derivative preparation regioselective; dihalo pyrrolopyrazine alkyne metal catalyst amination reaction.

An efficient methods for the synthesis of dipyrrolopyrazine derivatives, I [R1 = H, C6H5; R2 = C6H5, 4-F-C6H4, (CH3)2NC6H4, cyclopropyl, etc.] and II and pyrrolothieno-pyrazine derivatives, III (X = H, C6H5) that involve regioselective amination reactions of dihalo-pyrrolopyrazines IV [Y = H, CH3, 4-CH3C6H4S(O)2; A = Br; B = Cl] is reported. The developed protocol readily affords either 2-amino- or 3-amino-pyrrolopyrazines IV (A = Br, NHCH3; B = Cl, NHCH3) from the corresponding 2-bromo-3-chloro-5H-pyrrolo[2,3-b]pyrazines IV (A = Br; B = Cl). When the amination reactions was carried under metal-free microwave irradiation, 3-amino-pyrrolopyrazines IV (A = Br; B = NHCH3) was obtained exclusively. In contrast, Buchwald cross coupling of the 2-bromo-3-chloro-5H-pyrrolo[2,3-b]pyrazines IV (A = Br; B = Cl) affords only 2-amino-pyrrolopyrazine IV (A = NHCH3; B = Cl). The pyrrolopyrazine scaffolds was converted to the resp. 1,7- I and 1,5-dihydrodipyrrolo[2,3-b]pyrazines derivatives II using Sonogashira reactions. A comprehensive study of the optical properties, thermal properties, and mol. packing of the synthesized compounds was carried out. The results indicate that the 1,7-derivatives I may be promising organic materials for optoelectronic applications.

RSC Advances published new progress about Amination. 566205-01-4 belongs to class pyrazines, name is 2-Amino-3,5-dibromo-6-chloropyrazine, and the molecular formula is C4H2Br2ClN3, Computed Properties of 566205-01-4.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Muralirajan, Krishnamoorthy published the artcileExploring the Structure and Performance of Cd-Chalcogenide Photocatalysts in Selective Trifluoromethylation, Name: 2,3,5-Trimethylpyrazine, the main research area is trifluoromethylated arene oxindole alkene preparation photochem; heteroarene alkene selective trifluoromethylation cadmium selenide catalyst.

The field of heterogeneous photoredox catalysis has grown substantially and impacted organic synthesis because of the affordability and reusability of catalysts. This study reports radical trifluoromethylation with Cd-chalcogenide semiconductors. Cd semiconductors, particularly CdSe, are readily available, com., visible-light-responsive, heterogeneous photocatalysts. The potential of readily available Cd semiconductors, particularly CdSe, is confirmed by their increased photocatalytic activity toward trifluoromethylation with various substrates, such as (hetero)arenes and vinylic amides/acids, via addition, cyclization, and decarboxylation under visible light. The economic significance of this strategy is also highlighted through the scalable synthesis of biol. active mols. followed by catalyst reuse. Moreover, these catalysts are relatively inexpensive compared with transition metal-based homogeneous photocatalysts, presently used in organic synthesis.

ACS Catalysis published new progress about Cyclization. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Name: 2,3,5-Trimethylpyrazine.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Jin, Yusuke published the artcilePyrazine Analogues on Clathrate Hydrates in Methane-Water Systems, Formula: C7H10N2, the main research area is clathrate hydrate methane water methylpyrazine system Raman spectroscopy.

This paper reports the change in equilibrium pressure-temperature (pT) boundaries in a methane (CH4)-water system by adding three pyrazine analogs: 2-methylpyrazine, 2,3-dimethylpyrazine, and 2,3,5-trimethylpyrazine. The 2-methylpyrazine, 2,3-dimethylpyrazine, and 2,3,5-trimethylpyrazine showed no effect on the clathrate hydrate structure that formed in the CH4-water system upon anal. via Raman spectroscopy. Raman spectra revealed that clathrate crystals that formed in the CH4-pyrazine analog-water system were of a structure-I CH4 hydrate. Phase equilibrium pT boundaries in the three CH4-pyrazine analog-water systems shifted to a higher p and lower T condition than that for the CH4-water system with no additive. The higher p/lower T shift confirmed that 2-methylpyrazine, 2,3-dimethylpyrazine, and 2,3,5-trimethylpyrazine act as thermodn. inhibitors for hydrate formation. The order of ΔT, a lower T shift from the CH4-water system, was as follows: 2-methylpyrazine-water > 2,3-dimethylpyrazine > 2,3,5-trimethylpyrazine. This order is in agreement with the number of -CH3 groups in the mols.

Journal of Chemical & Engineering Data published new progress about Phase equilibrium. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Formula: C7H10N2.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Liao, Ke published the artcileCatalytic cleavage and functionalization of bulky and inert Csp3-Csp3 bonds via a relayed proton-coupled electron transfer strategy, Safety of 2,3,5-Trimethylpyrazine, the main research area is alc radicalophile acridinium tetrafluoroborate regioselective photochem bond cleavage functionalization.

The direct, photoredox cleavage of hindered Csp3-Csp3 bonds of alcs. under neutral conditions was described. A relayed proton-coupled electron transfer (PCET) strategy was employed that overcame the previous requirement of a Bronsted base. Heavily branched alcs. with a high oxidation potential (Eox1/2 > +2 V vs. SCE) were cleaved and functionalized with remarkable efficiency and versatility. A simple, non-substituted Ph group can promote a relayed PCET process to deliver primary, secondary, and tertiary alkyl radicals under neutral conditions.

Cell Reports Physical Science published new progress about Bond cleavage catalysts (photochem., regioselective). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Safety of 2,3,5-Trimethylpyrazine.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Guo, Qi published the artcileThe complete synthesis of favipiravir from 2-aminopyrazine, Related Products of pyrazines, the main research area is favipiravir preparation.

Favipiravir was synthesized from an inexpensive and com. available starting material, 2-aminopyrazine. The preferred route embedded within seven steps and was highlighted by the novel and efficient synthesis of 3,6-dichloropyrazine-2-carbonitrile. The intermediate 3,6-dichloropyrazine-2-carbonitrile was prepared in four successive steps which were regioselective chlorination of the pyrazine ring, bromination, Pd-catalyzed cyanation and Sandmeyer diazotization/chlorination. This protocol eliminated the hazardous POCl3 of previous synthetic methods and offered a better yield (48%) which was 1.3-fold higher than a recently published procedure. From intermediate 3,6-dichloropyrazine-2-carbonitrile, the subsequent nucleophilic fluorination, nitrile hydration and hydroxyl substitution efficiently afforded the target product. Another synthetic approach with the same starting material was also investigated to bypass the allergy-causing dichloro intermediate 3,6-dichloropyrazine-2-carbonitrile. The key step of monofluorination at the pyrazine C6 position of intermediate 6-chloro/bromo-3-aminopyrazine-2-carbonitriles and 6-chloro/bromo-3-hydroxylpyrazine-2-carbonitriles was not achieved.

Chemical Papers published new progress about. 356783-29-4 belongs to class pyrazines, name is 3,6-Difluoropyrazine-2-carboxamide, and the molecular formula is C5H3F2N3O, Related Products of pyrazines.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Liu, Feng-Liang published the artcileA practical and step-economic route to Favipiravir, Recommanded Product: 3,6-Difluoropyrazine-2-carboxamide, the main research area is favipiravir preparation.

A practical and step-economic route to Favipiravir, an antiviral drug, was developed. Favipiravir was synthesized in only six steps from 3-aminopyrazine-2-carboxylic acid with an overall yield of about 22.3%. Key intermediates Me 3-amino-6-bromopyrazine-2-carboxylate and 3,6-dichloropyrazine-2-carbonitrile were obtained in excellent purity via recrystallization from optimized solvents, which was beneficial to large-scale production In the key synthetic reaction, 3,6-dichloropyrazine-2-carbonitrile was reacted sequentially, in one pot, with KF and 30% H2O2 to give (after crystallization from 95% EtOH) favipiravir as colorless crystals, with a 60% yield for this final step of the synthesis.

Chemical Papers published new progress about. 356783-29-4 belongs to class pyrazines, name is 3,6-Difluoropyrazine-2-carboxamide, and the molecular formula is C5H3F2N3O, Recommanded Product: 3,6-Difluoropyrazine-2-carboxamide.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Petkevicius, Vytautas published the artcileA biocatalytic synthesis of heteroaromatic N-oxides by whole cells of Escherichia coli expressing the multicomponent, soluble di-iron monooxygenase (SDIMO) PmlABCDEF, Computed Properties of 14667-55-1, the main research area is sequence soluble di iron monooxygenase gene cluster pmlABCDEF; heteroaromatic oxide biocatalytic synthesis monooxygenase PmlABCDEF recombinant Escherichia.

Aromatic N-oxides (ArN-OX) are desirable biol. active compounds with a potential for application in pharmacy and agriculture industries. As biocatalysis is making a great impact in organic synthesis, there is still a lack of efficient and convenient enzyme-based techniques for the production of aromatic N-oxides. In this study, a recombinant soluble di-iron monooxygenase (SDIMO) PmlABCDEF overexpressed in Escherichia coli was showed to produce various aromatic N-oxides. Out of 98 tested N-heterocycles, seventy were converted to the corresponding N-oxides without any side oxidation products. This whole-cell biocatalyst showed a high activity towards pyridines, pyrazines, and pyrimidines. It was also capable of oxidizing bulky N-heterocycles with two or even three aromatic rings. Being entirely biocatalytic, our approach provides an environmentally friendly and mild method for the production of aromatic N-oxides avoiding the use of strong oxidants, organometallic catalysts, undesirable solvents, or other environment unfriendly reagents. The sequence of the p577A clone containing pmlABCDEF gene cluster was deposited in GenBank under the accession number MK037457.

Advanced Synthesis & Catalysis published new progress about DNA sequences (GenBank MK037457). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Computed Properties of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Yu, Hang published the artcileEffects of Ultrasonic Processing and Oil Type on Maillard Reaction of D-Glucose and L-Alanine in Oil-in-Water Systems, Computed Properties of 14667-55-1, the main research area is oil ultrasonic Dglucose Lalanine.

This study investigated the effects of high-intensity ultrasonic processing on a Maillard reaction (MR) model system of D-glucose and L-alanine and its corresponding oil-in-water systems with canola, olive, palm, and coconut oil, resp. The MR in the water phase was significantly promoted in the olive and canola oil-MR systems with the higher depletion of reactants and the higher generation of final MR products compared with those in the oil-free-MR model system; however, the MR was suppressed in the systems of palm and coconut oils. The concentration of pyrazines with shorter side chain, e.g., 2,5-dimethylpyrazine and 2,6-dimethylpyrazine, was significantly increased in the presence of oils with a lower degree of unsaturation; meanwhile, the oils with higher degree of unsaturation suppressed the generation of the shorter side chain-pyrazines, but promoted the generation of pyrazines with a longer side chain, e.g., 2,3-diethyl-5-methylpyrazine and 3,5-diethyl-2methylpyrazine. Due to the oils undergoing ultrasonic processing at 80 °C, the oxidation of oils was significantly promoted, as reflected by a relatively low iodine value and high peroxide and p-anisidine values in the processed oils compared with those in the raw oils. On one hand, various carbonyl compounds were generated due to the lipid oxidation; meanwhile, these carbonyl compounds participated in the MR as part of intermediate MR products and subsequently generated various desired flavors. On the other hand, off-flavors coming from the oxidation of oils were also detected, which may affect the overall flavor profile of the oil-in-water MR systems.

Food and Bioprocess Technology published new progress about Autoxidation. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Computed Properties of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Ooi, Teng Sin published the artcileVolatile organic compounds and sensory profile of dark chocolates made with cocoa beans fermented with Pichia kudriavzevii and Hanseniaspora thailandica, Formula: C7H10N2, the main research area is volatile organic compound dark chocolate cocoa bean Pichia Hanseniaspora; Chocolate; Cocoa beans; Sensory; Volatile organic compounds; Yeast starter.

Volatile organic compounds (VOCs) are important to determine the aroma and sensory perception of cocoa. Starter cultures can modulate the volatile profile of cocoa beans during fermentation This study aimed to determine the VOCs and sensory of chocolates produced using cocoa beans fermented with yeast starters (Pichia kudriavzevii (MH979681), Hanseniaspora thailandica (MH979675) and the mixture of the two yeasts (Mix)). The VOCs of chocolates were determined by Head-Space Solid Phase Microextraction followed by Gas Chromatog.-Mass Spectrophotometry. Sensory anal. was determined by using trained panels. VOCs profiles of chocolates produced using beans fermented with HT, PK or Mix were noticeably different from Ghana and control chocolates (no starter). The addition of yeast starters during cocoa fermentation produced chocolates that were preferred by trained panels. Bitterness and astringency were the more intense flavor attributes in chocolates produced using cocoa beans added with yeast starters. The chocolate produced using cocoa beans fermented with PK was the most acidic; whereas chocolate produced using beans fermented with Mix had the sweetest taste. The addition of PK or HT is helpful in producing chocolate with a distinct flavor.

Journal of Food Science and Technology (New Delhi, India) published new progress about Alcohols Role: BSU (Biological Study, Unclassified), FFD (Food or Feed Use), BIOL (Biological Study), USES (Uses). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Formula: C7H10N2.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem