Pyrazines

Reference of 143591-61-1, These common heterocyclic compound, 143591-61-1, name is 3-Bromo-8-chloroimidazo[1,2-a]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.

3-bromo-8-chloroimidazo [1,2-a] pyrazine (1.33 g, 5.7 mmol),1- (2-methoxyethyl) -1H-pyrazole-4-amine (0.96 g, 6.8 mmol) was added to 15 mL of n-butanol,The temperature was raised to 120 C and reacted overnight.The solvent was removed by rotary evaporation, diluted with 30 mL of water, and extracted with ethyl acetate (20 mL * 3). The organic phases were combined,It was washed with 20 mL of saturated brine, dried over anhydrous sodium sulfate, and concentrated.Separation through a silica gel column gave 1.45 g of a pale yellow solid with a yield of 76%.

The synthetic route of 143591-61-1 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Shenzhen Tajirui Bio-pharmaceutical Co., Ltd.; Wang Yihan; Xing Qingfeng; Ai Yixin; (85 pag.)CN110272426; (2019); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

22047-25-2, name is Acetylpyrazine, belongs to pyrazines compound, is considered to be a conventional heterocyclic compound, which is widely used in drug synthesis. The chemical synthesis route is as follows. Computed Properties of C6H6N2O

General procedure: A 100 mL round-bottom flask charged with 2-acetylpyrazine (1.47 g, 2 mmol) was added MeOH (30 mL), KOH pellets (0.675 g,2 mmol) and water (2 mL). The resulting mixture was stirred for10 min and then added corresponding n,n?-dimethoxybenzaldehydes (1.0 g, 1 mmol) and ammonium solution (6 mL) was added slowly stirring at room temperature for 4 h, a white precipitate obtained was filtered, washed with MeOH and diethyl ether. The crude products on recrystallization in a mixture of CHCl3:MeOH (1:1) gave white crystals of desired compounds, 1-4.

The synthetic route of 22047-25-2 has been constantly updated, and we look forward to future research findings.

Reference:
Article; Golla, Ramesh; Kumar, P. Raghavendra; Suchethan; Foro, Sabine; Nagaraju; Journal of Molecular Structure; vol. 1201; (2020);,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Some common heterocyclic compound, 16298-03-6, name is Methyl 2-aminopyrazine-3-carboxylate, molecular formula is C6H7N3O2, 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. name: Methyl 2-aminopyrazine-3-carboxylate

3-Aminopyrazine-2-carboxylic acid methyl ester (0.8 g, 5.2 mmol) and 3-bromopyridine (1.2 g, 7.8 mmol) were dissolved in 20 mL dry toluene. 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (0.6 g, 1.04 mmol), sodium tert.-butylate (0.75 g, 7.8 mmol) and tri(dibenzylideneacetone)dipalladium chloroform complex (0.54 g, 0.52 mmol) were added and the reaction mixture was stirred under microwave irradiation for 60 minutes at 150° C. The reaction mixture was then evaporated and purified by flash chromatography on silica gel (heptane/ethyl acetate 1:2->0:100 gradient). The desired product was obtained as a brown solid (260 mg, 22percent), MS: m/e=231.1 (M+H+).

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 16298-03-6, its application will become more common.

Reference:
Patent; Jaeschke, Georg; Kolczewski, Sabine; Porter, Richard Hugh Philip; Vieira, Eric; US2006/199828; (2006); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Electric Literature of 486460-20-2, 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. 486460-20-2 name is 3-(Trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine, 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.

To a solution of 3-(trifluoromethyl)-[l ,2,4]triazolo[4,3-a]pyrazine ( 1 .60 g) in metanol(20 mL) was added a catalytic amount of Pd/C. The suspension was stirred under H2 for 5 h, and then filtered. The filtrate was concentrated in vacuo to give a residue, which was used for next step without further purification.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 3-(Trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine, and friends who are interested can also refer to it.

Reference:
Patent; SUNSHINE LAKE PHARMA CO., LTD.; ZHANG, Jiancun; ZHANG, Yingjun; ZHANG, Weihong; LIU, Bing; ZHANG, Jiquan; LIU, Jinlei; ZHANG, Lu; WO2013/71697; (2013); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reference of 6905-47-1,Some common heterocyclic compound, 6905-47-1, name is 2-Amino-6-methoxypyrazine, molecular formula is C5H7N3O, 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.

To a mixture of MeOH (6 mL) in DMSO (12 mL) was added slowly NaH (1.2 g of 60% in oil, 30 mmol) and stirred at room temperature for 30 min. 2-amino-6-chloropyrazine (1.29 g, 10 mmol) was added to the mixture portionwise and heated at 80 C for 2 h. The reaction mixture was cooled, water was added and extracted with ethyl acetate. The organic layer was washed with brine, dried over MgSO4, filtered and concentrated. The residue was purified bycolumn chromatography to give 2-amino-6-methoxypyrazine (888 mg, 71%) as a slightly yellow solid. 1H NMR (200 MHz, CDCl3) delta 7.60 (s, 1H), 7.55 (s, 1H), 4.44 (br, 2H), 3.90 (s, 3H); 2-amino-6-methoxyprazine (186 mg, 1.45 mmol) was dissolved in MeOH. To the solution was added N-bromo-succinimide (568 mg, 3.19 mmol) and stirred at room temperature for 30 min. The reaction mixture was concentrated via vacuo, ethyl acetate was added and washed with water. The organic layer was dried over MgSO4, filtered and concentrated. The residue was purified by column chromatography to give a product 1e (242 mg, 59%). 1H NMR (200 MHz, CDCl3) delta4.91 (br, 2H), 3.96 (s, 3H);

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 2-Amino-6-methoxypyrazine, its application will become more common.

Reference:
Article; Kwak, Se Hun; Lee, Gee-Hyung; Gong, Young-Dae; Bulletin of the Korean Chemical Society; vol. 33; 12; (2012); p. 4271 – 4274;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

313339-92-3, Adding some certain compound to certain chemical reactions, such as: 313339-92-3, name is 3,5-Dichloropyrazine-2-carbonitrile, can increase the reaction rate and produce products with better performance than those obtained under traditional synthetic methods. Here is a downstream synthesis route of the compound 313339-92-3.

To a solution of 3,5-dichloropyrazine-2-carbonitrile (1.00 g, 5.47 mmol) in DMF (10 mL) was added (R)-()-3-amino-1-Boc-piperidine (1.38 g, 6.9 mmol) and DIPEA (2.0 mL, 10.94 mmol) in a dropwise manner. The mixture was stirred at room temperature for 60 min. The reaction mixture was evaporated under reduced pressure and the residue was purified by flash chromatography with 0 to 50% ethyl acetate in cyclohexane to give tert-butyl (3R)-3-[(6-chloro- 5-cyanopyrazin-2-yl)amino]piperidine-1-carboxylate (2.36 g, quantitative yield).

Chemical properties determine the actual use. Each compound has specific chemical properties and uses. We look forward to more synthetic routes in the future to expand reaction routes of 313339-92-3.

Reference:
Patent; PHARMACYCLICS LLC.; ATALLAH, Gordana, Babic; CHEN, Wei; JIA, Zhaozhong, J.; POZZAN, Alfonso; RAVEGLIA, Lucal, Francesco; ZANALETTI, Riccardo; (815 pag.)WO2016/196776; (2016); A2;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Some common heterocyclic compound, 123-32-0, name is 2,5-Dimethylpyrazine, molecular formula is C6H8N2, 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. 123-32-0

(b) 3,6-Dimethylpyrazin-2-amine A mixture of 2,5-dimethylpyrazine (14 g, 0.13 mol) in N,N-dimethylaniline (50 mL) was heated to 170 C. and NaNH2 (22 g, 0.56 mol) was added in portions. The reaction mixture was stirred at 170 C. for 1 h, and the solvent was removed. The product was purified by silica gel column chromatography to give 3,6-dimethylpyrazin-2-amine as a brown solid (1.6 g, yield 10%). ESI MS: m/z 124 [M+1]+.

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 123-32-0, its application will become more common.

Reference:
Patent; Sunovion Pharmaceuticals Inc.; US2012/178748; (2012); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reference of 54608-52-5, These common heterocyclic compound, 54608-52-5, name is 2-Hydrazinopyrazine, 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.

Step 3 Hydrazinopyrazine (6.2 g, 57 mmol) and 1-(2-chloropyridin-4-yl)-2-(4-fluorophenyl)ethanone (14 g, 57 mmol) were suspended in benzene (250 ml) and p-toluenesulfonic acid monohydrate (0.68 g) was added. The reaction mixture was then refluxed with azeotropic removal of water via Dean Stark trap. After 2 h, the benzene was removed in vacuo and di-ethylene glycol was added. The reaction mixture was heated at reflux. After 2 h, the reaction mixture was poured into ether with vigorous stirring. Water was added and the product was extracted into ether. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo. Methanol was added and the solid was filtered off to give 6-(2-chloropyridin-4-yl)-7-(4-fluorophenyl)-5H-pyrrolo[2,3-b]pyrazine (4.9 g) as a solid.

The synthetic route of 54608-52-5 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Syntex (U.S.A.) LLC; US6316464; (2001); B1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reference of 41110-29-6, The chemical industry reduces the impact on the environment during synthesis 41110-29-6, name is Methyl 3-methylpyrazine-2-carboxylate, I believe this compound will play a more active role in future production and life.

a) 3-Methyl-4-oxy-pyrazine-2-carboxylic acid methyl ester To a solution of 2.0 g (13.14 mmol) 3-methyl-pyrazine-2-carboxylic acid methyl ester in 40 ml CHCl3 was added 3.24 g (13.14 mmol) meta-chlorperoxybenzoic acid and the resulting mixture was heated to reflux for 1.5 h. The reaction mixture was basified with saturated aqueous NaHCO3 and extraced with CHCl3, the combined organic layers were dried with Na2SO4 and evaporated. The residue was purified by chromatography on silica gel (DCM to DCM/MeOH 9:1) to provide the title compound as colorless solid. HPLC: RtH11=0.40 min; ESIMS [M+H]+=169; 1H NMR (600 MHz, DMSO-d6): 8.56 (d, 1H), 8.48 (d, 1H), 3.33 (s, 3H).

In the field of chemistry, the synthetic routes of compounds are constantly being developed and updated. I will also mention this compound in other articles, Methyl 3-methylpyrazine-2-carboxylate, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; NOVARTIS AG; US2012/172359; (2012); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Electric Literature of 356783-16-9, These common heterocyclic compound, 356783-16-9, name is 3,6-Dichloropyrazine-2-carbonitrile, 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.

REFERENTIAL EXAMPLE II-12 In 25 mL of dimethylformamide was dissolved 2.5 g of 3,6-dichloro-2-pyrazinecarbonitrile. After adding 3.2 g of 4-(benzyloxy)phenol and 3.0 g of potassium carbonate, the mixture was stirred at room temperature for one hour. A mixture of 25 ml of ethyl acetate and 100 mL of water was added to the reaction mixture, and the organic layer was separated. The organic layer thus obtained was washed successively with water and saturated aqueous solution of sodium chloride and dried on anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Diisopropyl ether was added to the residue, the insoluble matter was filtered off, and the filtrate was concentrated. The residue thus obtained was washed with n-hexane to obtain 3.84 g of 3-[(4-(benzyloxy)phenoxy)]-6-chloro-2-pyrazinecarbonitrile as a light brown-colored solid product. R (KBr) cm-1: 2238 H-NMR (CDCl3) delta: 5.12(2H,s), 7.03-7.48(9H,m), 8.65(1H,s)

Statistics shows that 3,6-Dichloropyrazine-2-carbonitrile is playing an increasingly important role. we look forward to future research findings about 356783-16-9.

Reference:
Patent; Toyama Chemical Co., Ltd.; US2003/130213; (2003); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem