Month: September 2021

Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 2423-65-6, name is Pyrazine 1-oxide, A new synthetic method of this compound is introduced below., Computed Properties of C4H4N2O

General Procedure 2:; Palladium-Catalyzed Direct Arylation with Aryl Chlorides and Bromides.; To a dried flask was added the diazine N-oxide (1.0 to 3.0 equiv.), K2CO3 (2.0 equiv.), Pd(OAc)2 (5 mol %) and HP(t-Bu)3BF4 (15 mol %). If the arylhalide is a solid, it is added at this point (1.0 equiv.). The flask and its contents were then purged under nitrogen for 10 minutes. If the aryl halide is a liquid, it is added via syringe after purging, followed by the addition of degassed dioxane (to produce a reaction concentration of 0.3 M relative to the halide). The reaction mixture was then heated at 110 C. until the reaction was complete, after which the volatiles were removed under reduced pressure and the residue was purified via silica gel column chromatography.; 2-p-Tolylpyrazine N-oxide (81) Synthesised according to general procedure 2 employing the corresponding aryl bromide and chloride or 60 with the corresponding aryl iodide. Purification via silica gel column chromatography using 100% DCM then a mixture of 20% Acetone/DCM gave a white solid, 72% (from the bromide), 75% (from the chloride) and 77% (from the iodide). 1H NMR (300 MHz, CDCl3, 293K, TMS): delta 8.63 (1H, s), 8.37 (1H, s), 8.20 (1H, s), 7.72 (2H, d, J=8.1 Hz), 7.33 (2H, d, J=7.8 Hz), 2.43 (3H, s). 13C NMR (75 MHz, CDCl3, 293K, TMS): 148.2, 145.2, 144.6, 140.8, 134.2, 129.8, 129.0, 125.9, 21.5.

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.

Reference:
Patent; University of Ottawa; US2008/132698; (2008); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 330786-09-9, name is Methyl 3,5-dichloropyrazine-2-carboxylate, A new synthetic method of this compound is introduced below., HPLC of Formula: C6H4Cl2N2O2

b) Synthesis of 3-chloro-5-morpholin-4-yl-pyrazine-2-carboxylic acid methyl ester To a solution of 3,5-dichloro-pyrazine-2-carboxylic acid methyl ester (1.20 g, 5.82 mmol) in dimethylformamide (12 ml) is added potassium carbonate (0.96 g, 6.98 mmol) at RT followed by the addition of morpholine (0.5 ml, 5.82 mmol). The resulting mixture is stirred at RT for 3 h. After completion of the reaction, the mixture is diluted with water (20 ml) and extracted with EtOAc (3*30 ml). The combined organic layers are washed with water (30 ml), brine (30 ml), dried over anhydrous sodium sulfate and evaporated in vacuo to get the crude product, which is purified by column chromatography (silica gel, 10% acetone/hexane) to yield 3-chloro-5-morpholin-4-yl-pyrazine-2-carboxylic acid methyl ester (1.10 g, 4.28 mmol, 73%).

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.

Reference:
Patent; GRUeNENTHAL GMBH; LUCAS, Simon; Kuehnert, Sven; Bahrenberg, Gregor; Schroeder, Wolfgang; US2014/148454; (2014); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

38557-72-1, Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 38557-72-1, name is 2-Chloro-3,5-dimethylpyrazine, A new synthetic method of this compound is introduced below.

Step 1: Synthesis of 3,5-Dimethyl-2-(dibenzofuran-4-yl)pyrazine (abbreviation: Hdm4 dbfpr) First, into a recovery flask equipped with a reflux pipe were placed 1.51 g of 2-chloro-3,5-dimethylpyrazine, 2.25 g of 4-dibenzofuranylboronic acid, 1.12 g of sodium carbonate, 0.048 g of bis(triphenylphosphine)palladium(II) dichloride (abbreviation: Pd(PPh3)2Cl2), 15 mL of water, and 15 mL of acetonitrile, and the air inside the flask was replaced with argon. Heating was performed by microwave irradiation (2.45 GHz, 100 W) of this reaction container for 10 minutes, so that reaction occurred. After that, water was added to this reaction solution, and extraction with dichloromethane was carried out. A solution of the obtained extract was washed with water and dried over magnesium sulfate. After the drying, the solution was filtered. After the solvent of this solution was distilled, the obtained residue was washed with methanol, so that the pyrazine derivative which was the object of the synthesis, Hdm4 dbfpr, was obtained (a pale orange powder in a yield of 65%). Note that a microwave synthesis system (Discover, produced by CEM Corporation) was used for the microwave irradiation. The synthesis scheme of Step 1 is illustrated in the following scheme (x-1).

If you are interested in these compounds, you can also browse my other articles.Thank you for taking the time to read this article. I hope you enjoyed it.

Reference:
Patent; Semiconductor Energy Laboratory Co., Ltd.; US2012/104373; (2012); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Electric Literature of 1458-18-0,Some common heterocyclic compound, 1458-18-0, name is Methyl 3-amino-5,6-dichloropyrazine-2-carboxylate, molecular formula is C6H5Cl2N3O2, 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.

Methyl 3-amino 5,6-dichloro-2-pyrazinecarboxylate (10 g, 45 mmol) was placed in a three-necked round bottom flask flushed with nitrogen, equipped with a bubbler and a gas condensor. The round bottomedflask and condensor were cooled to -80 C using a dry ice in acetone bath. Gaseous ammonia (500 mL) was condensed into the flask over a period of 1.5 h. Thereaction mixture was allowed to warm to reflux and maintained at reflux for a period of10 h. The ammonia then was allowed to evaporate from the flask (fume hood!) and the solid obtained was dried under high vacuum overnight to provide 3-amino-5,6-dichloro-2-pyrazinecarboxamide 4 (9.5 g, 100%) as solid,

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route Methyl 3-amino-5,6-dichloropyrazine-2-carboxylate, its application will become more common.

Reference:
Article; Massey, Archna P.; Harley, William R.; Pasupuleti, Nagarekha; Gorin, Fredric A.; Nantz, Michael H.; Bioorganic and Medicinal Chemistry Letters; vol. 22; 7; (2012); p. 2635 – 2639;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

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