Pyrazines

Some common heterocyclic compound, 3149-28-8, name is 2-Methoxypyrazine, molecular formula is C5H6N2O, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. Quality Control of 2-Methoxypyrazine

Preparation 37; 2-Methoxy-3- (3-methoxy-4-nitrophenyl) pyrazine (P37); 2,2, 6, 6-Tetramethylpiperidine (0.71 mL, 4.21 mmol) was added to a solution of n- butyllithium (1.6M, 2.6 mL, 4.16 mmol) in tetrahydrofuran (10 mL) at-30C. The mixture was allowed to warm up to 0C and stirred at that temperature for 15 minutes. The solution was then cooled to-70C, a solution of 2-methoxypyrazine (200 mg, 1.80 mmol) in tetrahydrofuran (5 mL) was added and then the mixture stirred at that temperature for 30 minutes. A solution of zinc chloride (500 mg, 3.67 mmol) in tetrahydrofuran (5 mL) was subsequently added at-70C and the mixture was then allowed to warm slowly to room temperature. A solution containing tetrakis (triphenylphosphine) palladium (0) (83 mg, 0.07 mmol) and 4-bromo-2-methoxy-1-nitrobenzene (459 mg, 1.98 mmol) in tetrahydrofuran (5 mL) was added to the organozinc derivative and the mixture heated at 65C for 2 hours. The reaction mixture was then hydrolyse with a solution containing ethylenediaminetetraacetic acid (1.1 g, 3.7 mmol) in water (10 mL) which had been made slightly basic with a saturated aqueous solution of potassium carbonate. The aqueous phase was extracted with dichloromethane (3×100 mL) and the combined extracts dried over magnesium sulfate and concentrated in vacuo. The product was purified by silica gel chromatography eluting with 0 to 80% ethyl acetate in hexane to yield the title compound as a solid ; MS (APCI+ve) : [M+H] + at m/z 262 (C12H11N304 requires [M+H] + at m/z 262).

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 3149-28-8, its application will become more common.

Some common heterocyclic compound, 768-05-8, name is Pyrazinoic acid hydrazide, molecular formula is C5H6N4O, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. Recommanded Product: Pyrazinoic acid hydrazide

General procedure: A mixture of the corresponding acylhydrazine (3 mmol), potassium phosphate (1.02 g, 3 mmol), and carbon disulfide (0.23 g, 3 mmol) in water (15 mL) was stirred at rt for 10 min. After refluxing for an additional 2-3 h, propylene oxide (0.18 g, 3 mmol) was added. Stirring was continued at rt until the intermediate convert completely (monitored by TLC, about 0.5-1 h), the mixture was extracted with EtOAc (3×10 mL). The combined organic layer was washed with water and dried over Na2SO4. The solvent was evaporated under reduced pressure, and the residue was purified by recrystallization or silica gel column to afford the corresponding product 10a-l.

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 768-05-8, its application will become more common.

In the chemical reaction process, reaction time, type of solvent, can easily affect the result of the reaction, thereby determining the yield and properties of the reaction product. An updated downstream synthesis route of 54608-52-5 as follows. Recommanded Product: 54608-52-5

General procedure: p-TsOH (9.5 mg, 55 mumol, 5 mol %) and MnO2 (348 mg, 4.00 mmol) were added to a stirred solution of heterocyclic hydrazine 1a-d (1 mmol) and aldehyde 2a-k (1.2 mmol) in PhMe (10 ml). The mixture was heated at 80C until the starting material was completely consumed (monitored by TLC, 40-55 min) and then cooled down to room temperature. After filtration and evaporation of solvent from the filtrate, the resulting residue was purified by silica gel column chromatography affording pure products.

According to the analysis of related databases, 54608-52-5, the application of this compound in the production field has become more and more popular.

Synthetic Route of 5780-66-5,Some common heterocyclic compound, 5780-66-5, name is Pyrazine-2-carbaldehyde, molecular formula is C5H4N2O, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.

As shown in scheme 1, nitromethane (11.1 mL, 207 mmol, 1.5 eq) was added to a solution of the pyrazine aldehyde (15 g, 138 mmol) in 35 mL of anhydrous THF. The solution was cooled to 0° C. Potassium tert-butoxide (13.8 mL of 1 M solution in THF, 13.8 mmol, 0.1 eq) was added dropwise keeping the solution temperature below 5° C. A yellow precipitate formed upon addition of base. After addition of base was complete, the reaction was stirred for 15 minutes at 0° C. The solution was poured into 250 mL of water and extracted with EtOAc (3.x.250 mL). The combined organics were washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified via silica plug and eluted with 60percent EtOAc/hexanes. The product (1) was a yellow viscous oil (15.1 g, 64percent). LC/MS (M+1) 170.

The synthetic route of 5780-66-5 has been constantly updated, and we look forward to future research findings.

These common heterocyclic compound, 1196152-38-1, name is 2-Bromo-5-(trifluoromethyl)pyrazine, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. Recommanded Product: 1196152-38-1

Description 121: 1,1-dimethylethyl (lS,4S,6S)-4-({[5-(trifluoromethyl)-2- pyrazinylJoxyJmethylJ-S-azabicyclo^.l.OJheptane-S-carboxylate (D121); To a solution of 1,1-dimethylethyl (lR,4S,6R)-4-(hydroxymethyl)-3- azabicyclo[4.1.0]heptane-3-carboxylate D104 (120 mg) and 2-bromo-5-(trifluoromethyl)pyrazine D66 (120 mg) in DMF (2 ml) at 00C (ice bath) was added NaH (31.7 mg, 0.792 mmol) (gas evolution). The reaction mixture was slowly warmed to room temperature and stirred at room temperature for 1 hour. The reaction was quenched by a slow and careful addition of saturated aqueous solution of NaHCCb (40 ml). The organic phase was extracted with DCM (3×20 ml), the combined organic phases were washed with water and brine, dried over Na2SO4, filtered and concentrated to give the title compound D121 (150 mg) which was used in the next step without any purification.UPLC (Acid Final QC): rt = 0.89 minutes, peak observed: 274 (M+l – Boc), 374 (M+l) C17H22F3NsOs requires 373.

The synthetic route of 2-Bromo-5-(trifluoromethyl)pyrazine has been constantly updated, and we look forward to future research findings.

Reference of 21279-62-9, As we all know, there are many different methods for the synthesis of a compound, and people can choose the synthesis method that suits their own laboratory according to the actual situation. 21279-62-9 name is 3-Chloropyrazine-2-carboxamide, This compound is widely used in many fields, so it is necessary to find a new synthetic route. The downstream synthesis method of this compound is introduced below.

General procedure: Compounds 1-6 were prepared according to conventional organic synthesis methods. 3-Chloropyrazine-2-carboxamide (1.27 mmol) was dissolved in THF (20 mL) in a round bottom flask and after that treated with two equivalents of the corresponding benzylamine and an equimolar amount of triethylamine. The reaction was conducted with continuous stirring and heating (70 C) under reflux in an oil bath for 15 h. Compounds 7-15 were synthesised using a microwave reactor with a focused field. 3-Chloropyrazine-2-carboxamide (1.27 mmol) was put into a thick-walled tube together with the corresponding benzylamine (2.54 mmol), pyridine (1.27 mmol), methanol (approx. 5 mL) and a magnetic stir bar and then sealed with a special cap. The reaction parameters were set according to the previously published paper as follows-140 C, 30 min, 200 W [29]. Reaction progress was checked by TLC (hexane:ethyl acetate-1:1). Regardless of the synthesis method used,all reaction mixtures were adsorbed on silica and subjected to preparative flash chromatography (hexane and ethyl acetate, gradient elution, detection wavelengths 260 nm and 280 nm). Products were recrystallized from ethanol or ethanol and water if necessary. All final substances were chemically characterized (1H-NMR, 13C-NMR, IR, melting point and elemental analysis).

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 3-Chloropyrazine-2-carboxamide, and friends who are interested can also refer to it.

Related Products of 55557-52-3, As we all know, there are many different methods for the synthesis of a compound, and people can choose the synthesis method that suits their own laboratory according to the actual situation. 55557-52-3 name is 3-Chloropyrazine-2-carbonitrile, This compound is widely used in many fields, so it is necessary to find a new synthetic route. The downstream synthesis method of this compound is introduced below.

2-Cyano-3-chloropyrazine (1.5 g, 10.8 mmol) and Raney-Ni (50% slurry in water, 0.5 g) were added to 15 mL of glacial acetic acid under nitrogen for three times.Stir at 50 C overnight under a hydrogen atmosphere of 3 atm. After the reaction is complete, it is filtered.The filtrate was concentrated and the residue dissolved in ethyl acetate.Dry over anhydrous sodium sulfate, concentrate,The pale yellow oil was separated by a silica gel column (0.82 g).The yield was 53%.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 3-Chloropyrazine-2-carbonitrile, and friends who are interested can also refer to it.

Application of 1111638-10-8, In the chemical reaction process, reaction time, type of solvent, can easily affect the result of the reaction, thereby determining the yield and properties of the reaction product. An updated downstream synthesis route of 1111638-10-8 as follows.

To a solution of 3-chloro-5H-pyrrolo[2,3-b ]pyrazine (300 mg, 1.95 mmol) in2-methyltetrahydrofuran (10 mL) was added NIS (543 mg, 2.34 mmol), and the reaction mixturewas stirred at rt for 1 h. Saturated aqueous sodium thiosulfate (50 mL) was added to quench thereaction, and the resulting mixture was partitioned. The aqueous layer was extracted with EtOAc(50 mL x 2). The combined organic phases were washed with saturated brine (80 mL), driedover anhydrous Na2S04, filtered, and the filtrate was concentrated in vacuo to give the titlecompound as a yellow solid (546 mg, 100 %).MS (ESI, pos. ion) m/z: 280.2 [M+Ht.

According to the analysis of related databases, 1111638-10-8, the application of this compound in the production field has become more and more popular.

Each compound has different characteristics, and only by selecting the characteristics of the compound suitable for a specific situation can the compound be applied on a large scale. 22047-25-2, name is Acetylpyrazine, This compound has unique chemical properties. The synthetic route is as follows., name: Acetylpyrazine

A magnetic stirrer is added to the 250ml single-mouth eggplant bottle.Then add 1.85 g of p-bromobenzaldehyde, 2.44 g of 2-acetylpyrazine and 40 ml of ethanol.After stirring to completely dissolve, add 0.40 g of NaOH and 30 ml of concentrated ammonia water, and stir at room temperature for 6 hours.Filtration under reduced pressure, the filter cake was washed with ethanol and deionized water, and dried in vacuo to give Intermediate 4 as white solid, yield 1.75 g, yield 44.1%.The product was not further purified and the next reaction was carried out directly.

According to the analysis of related databases, 22047-25-2, the application of this compound in the production field has become more and more popular.

Application of 24241-18-7, A common heterocyclic compound, 24241-18-7, name is 2-Amino-3,5-dibromopyrazine, molecular formula is C4H3Br2N3, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.

18b (3.0 g, 12 mmol) was added into acetic acid (20 mL) and concentrated sulfuric acid (4 mL) under ice bath. To this mixture was added a pre-prepared solution of NaNO2 (1.65 g, 24 mmol) in water (10 mL). The reaction mixturewas stirred at room temperature for 3 h, and then poured into ice water (100 g). The precipitate was collected by filtrated, washed with water and dried to give an off-white solid (1.8 g, yield 61%). 3,5-Dibromo-2-hydroxylpyrazine (21b)Yield: 61%, off-white solid, M.p.: 182-184 C. 1H NMR(400 MHz, CDCl3):delta 11.23 (br, 1H), 7.53 (s, 1H). 1HNMR (400 MHz, DMSO-d6): delta 13.16 (s, 1H), 7.94 (s, 1H).13C NMR (125 MHz, CD3OD): delta 154.19, 136.73, 131.57, 114.62. ESI-MS m/z: 250.9 [M – H]-.

The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.