Pyrazines

Reference of 4858-85-9, A common heterocyclic compound, 4858-85-9, name is 2,3-Dichloropyrazine, molecular formula is C4H2Cl2N2, 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.

Starting material A-1 (15 g; 100.68 mmol) and hydrazine hydrate 65 % (15.509 ml201.37 mmol) are dissolved in 45 ml_ ethanol and stirred for 1 h at 80 C. While cooling down, a precipitate is formed. It is slurred up with a small amount of water and filtered off. It is washed with water and then dried to afford the product. Yield: 93 % (13.6 g; 94.07mmol) (0279) HPLC-MS: (M+H)+ = 145/147; tRet = 0.34 min; method FECB5

The synthetic route of 4858-85-9 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; BOEHRINGER INGELHEIM INTERNATIONAL GMBH; TONTSCH-GRUNT, Ulrike; BAUM, Anke; RUDOLPH, Dorothea Ingrid; (85 pag.)WO2019/145410; (2019); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reference of 6863-73-6, A common heterocyclic compound, 6863-73-6, name is 3-Chloropyrazin-2-amine, molecular formula is C4H4ClN3, 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.

alpha-Bromo diethyl acetal (51.6 mL, 332.7 mmol, 2.5 eq) was added to a solution of 7.7 mL HBr (conc.) and 80 mL of H2O. The reaction was heated at reflux for 1 h. The reaction was cooled and extracted 2× with Et2O (200 mL). The Et2O extracts were combined, washed with brine, and dried over Na2SO4 before being concentrated. The material was not left on the rotavap for an extended time or put under high vacuum. The oily residue was mixed with DME (200 mL) and the 2-amino-3-chloropyrazine (2, 17.240 g, 133.1 mmol) was added. HBr conc. (1-1.5 mL) was added and the reaction was heated at reflux. The reaction is heterogeneous reaction mixture, becomes homogenous after 10-15 minutes. After approximately 30 minutes a precipitate begins to form. After 1 hour at reflux the black reaction was cooled to room temperature, filtered, and washed with Et2O (4×, 75 mL) to give compound 101 1H NMR (DMSO-d6, 400 MHz) 8.70 (d, J=2.0 Hz, 1H), 8.32 (s, 1H), 7.93 (s, 1H), 7.79 (d, J=3.0 Hz, 1H). LC/MS shows a mixture of two products (one product by LC and two by MS). By MS there is a mass for XCl (major) MH+=154 (m/z) and one for XBr (minor) MH+ 198 (m/z). This mixture gave the product in approximately 90% yield as the HBr salt.

The synthetic route of 6863-73-6 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Schering Corporation; US2007/105864; (2007); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Electric Literature of 14508-49-7, These common heterocyclic compound, 14508-49-7, name is 2-Chloropyrazine, 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.

A mixture of 2-chloropyrazine (28.6 g, 0.25 mol) and thiourea (19 g, 0.25 mol) were added into 200 mL ethanol. The mixture was refluxed for 3 h under vigorous stir in a 500 mL three-necked flask. After alcohol was removed by the evaporation, diluted sodium hydroxide solution (30 wt%, 300 g) was gradually added into the flask. The mixture was heated with reflux for another 5 h and a large amount of ammonia was released. After cooled to ambient temperature, the pH of the solution was adjusted to 6.5 by adding quantitatively diluted hydrochloric acid. Extraction was carried out with dichloromethane. Dichloromethane layerwas collected and washed with water for several times. Yellow powder was obtained through evaporation in 68% (wt) yield. The whole synthesis is illustrated in Scheme 1. The elemental analysisresult for C4HN2S in mass %: C, 35.82; H, 2.25; N, 20.89. Experiment:C, 36.13; H, 2.01; N, 20.56.

Statistics shows that 2-Chloropyrazine is playing an increasingly important role. we look forward to future research findings about 14508-49-7.

Reference:
Article; Wu, Yining; Wu, Xuepeng; Fang, Sisi; Yang, Shuai; Li, Weitao; Wang, Huan; Yu, Xiaoxi; Polyhedron; vol. 122; (2017); p. 155 – 160;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Adding a certain compound to certain chemical reactions, such as: 38557-72-1, name is 2-Chloro-3,5-dimethylpyrazine, belongs to pyrazines compound, 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 38557-72-1, name: 2-Chloro-3,5-dimethylpyrazine

Step 1: Synthesis of 3,5-Dimethyl-2-(4-naphthalen-1-yl-phenyl)pyrazine (abbreviation: Hdm1nppr)First, into a recovery flask equipped with a reflux pipe were placed 0.74 g of 2-chloro-3,5-dimethylpyrazine, 1.29 g of 4-(1-naphthyl)phenylboronic acid, 0.55 g of sodium carbonate, 0.024 g of bis(triphenylphosphine)palladium(II) dichloride (abbreviation: Pd(PPh3)2Cl2), 10 mL of water, and 10 mL of acetonitrile, and the air in the flask was replaced with argon. This reaction container was irradiated with microwaves (2.45 GHz, 100 W) for 15 minutes, so that heating was performed. Then, the reaction container was cooled to 50 C. or less. Water was added to the reaction solution, and the organic layer was extracted with dichloromethane. The obtained organic layer was washed with water and dried with magnesium sulfate. The solution which had been dried was filtered. The solvent of this solution was distilled, and recrystallized using ethyl acetate, whereby Hdm1nppr, which is the pyrazine derivative to be produced, was obtained (as a white powder in 50% yield). Note that the microwave irradiation was performed using a microwave synthesis system (Discover, manufactured by CEM Corporation). The synthesis scheme of Step 1 is illustrated in the following (a-1).

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 2-Chloro-3,5-dimethylpyrazine, and friends who are interested can also refer to it.

Reference:
Patent; Semiconductor Energy Laboratory Co., Ltd.; US2011/245495; (2011); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Application of 33332-25-1,Some common heterocyclic compound, 33332-25-1, name is Methyl 5-chloropyrazine-2-carboxylate, molecular formula is C6H5ClN2O2, 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 solution of methyl-5-chloropyrazine-2-carboxylate (120 mg, 0.70 mmol) in a mixture of acetonitrile (2 ml) and DMF (1 ml) was added lithium chloride (295 mg, 6.95 mmol). The suspension was heated to 1600C for 5 mins in a Smith creator microwave after which time the reaction was diluted with water (10 ml). Saturated sodium bicarbonate solution (20 ml) was added and the aqueous layered extracted twice with ethyl acetate (30 ml). The combined organics were discarded and the aqueous layer adjusted to pH 4 with IN hydrochloric acid. The aqueous phase was extracted twice with ethyl acetate (20 ml) and the combined organics washed with water (2 x 20 mlL), brine (10 ml) and dried (MgSO4). The volatiles were removed to give the title compound as a colourless solid (68 mg), 1H NMR delta (CDCl3): 7.20 (IH, br s), 8.72 (IH, s), 9.21 – 9.21 (IH, m); m/z 157 (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 Methyl 5-chloropyrazine-2-carboxylate, its application will become more common.

Reference:
Patent; ASTRAZENECA AB; ASTRAZENECA UK LIMITED; WO2006/125958; (2006); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reference of 113305-94-5,Some common heterocyclic compound, 113305-94-5, name is 5-Aminopyrazine-2-carbonitrile, molecular formula is C5H4N4, 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 suspension of 5-aminopyrazine-2-carbonitrile (44.3 mg, 0.37 mmol) in THF (10 mL) was added NaH (24.4 mg, 0.61 mmol) at 0 C. The resulting mixture was stirred at ambient temperature for 1 h. A solution of compound 3 05-5 (120 mg, 0.3 lmmol) in THF (2 mL) was added and stirred at 55 C for 3.5 h. The reaction mixture was quenched with ice water and extracted with ethyl acetate. The organic layer was washed with water and brine, dried over anhydrous Na2SO4 and concentrated. The crude product was purified by column chromatography (hexanes/ethyl acetate: 3/1) to afford the title compound 306-5 as a yellow solid (110 mg, 77 % yield).

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 5-Aminopyrazine-2-carbonitrile, its application will become more common.

Reference:
Patent; PHARMAENGINE, INC.; CAI, Xiong; QIAN, Changgeng; WANG, Yanong Daniel; (98 pag.)WO2017/132928; (2017); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Related Products of 14508-49-7,Some common heterocyclic compound, 14508-49-7, name is 2-Chloropyrazine, molecular formula is C4H3ClN2, 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.

A mixture of 2-chloropyrazine (4.00 g) and hydrazine hydrate was heated at 110 C. for 1 h, and then cooled to room temperature. The mixture was filtered to give the title compound as a solid (2.30 g, 60.00%). The compound was characterized by the following spectroscopic data: MS (ESI, pos. ion) m/z: 111.0 (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 2-Chloropyrazine, its application will become more common.

Reference:
Patent; SUNSHINE LAKE PHARMA CO., LTD.; Zhang, Jiancun; Zhang, Yingjun; Zhang, Weihong; Liu, Bing; Zhang, Jiquan; Liu, Jinlei; Zhang, Lu; US2014/228361; (2014); 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. 38557-72-1, name is 2-Chloro-3,5-dimethylpyrazine, A new synthetic method of this compound is introduced below., Recommanded Product: 38557-72-1

To 2-chloro-3,5-dimethylpyrazine (2.8 g) were added 1-(tert-butoxycarbonyl)piperazine (3.7 g),palladium(II)acetate (225 mg),2-(dicyclohexylphosphino)-2′,4′,6′-triisopropylbiphenyl (953 mg),sodium tert-butoxide (2.7 g) and toluene (40 mL) and the mixture was stirred under reflux for 8 hr. Water was added to the reaction mixture and the mixture was extracted with ethyl acetate. The solvent was evaporated and the obtained residue was purified by column chromatography (hexane:ethyl acetate)to give 3′,5′-dimethyl-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid tert-butyl ester (5 g).

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; Mitsubishi Tanabe Pharma Corporation; ISHIBUCHI, Seigo; SARUTA, Kunio; HAMADA, Maiko; MATOBA, Nobuatsu; MATSUDAIRA, Tetsuji; SEKI, Maki; TARAO, Akiko; HONJO, Takashi; OGATA, Shingo; KAWATA, Atsushi; MOROKUMA, Kenji; FUJIE, Naoto; AOYAMA, Yukio; (251 pag.)EP3321256; (2018); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Adding a certain compound to certain chemical reactions, such as: 5521-55-1, name is 5-Methylpyrazine-2-carboxylic acid, belongs to pyrazines compound, 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 5521-55-1, HPLC of Formula: C6H6N2O2

General procedure: To the dipeptide salt (7 or 11, 1 mmol) in Schemes 2 and 3 wasadded a solution of 7 N NH3 in CH3OH (10 mL) and reaction mixturewas stirred for 10 min at 0 C. The solvent was evaporatedunder reduced pressure to afford free peptides, which was dissolvedin DMF (4 mL) and cooled to 4 C. To this reaction mixturerequisite carboxylic acid (1 mmol), DIC (1.1 mmol) and HOBt(1.1 mmol) was added and stirring continued at 4 C for 36 h. Thesolvent was removed under reduced pressure and the resultingresidue purified by column chromatography over neutral alumina using CHCl3/CH3OH (4:1) as eluant to afford desired peptides.The peptides were checked for their homogeneity on aShimadzu SPD-M20A HPLC system using a Supelcosil LC-8(25 cm 4.6 mm ID) column. The peptides were analyzed by usingan isocratic solvent system of CH3CN-H2O-TFA (70:30:0.8%) usinga SUPELCOSIL C-18 column with a flow rate of 1 mL/min

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:
Article; Meena, Chhuttan L.; Thakur, Avinash; Nandekar, Prajwal P.; Sangamwar, Abhay T.; Sharma, Shyam S.; Jain, Rahul; Bioorganic and Medicinal Chemistry; vol. 23; 17; (2015); p. 5641 – 5653;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Electric Literature of 4774-14-5, These common heterocyclic compound, 4774-14-5, name is 2,6-Dichloropyrazine, 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 1. Preparation of (2-chlorophenyl)-(3,5-dichloropyrazin-2-yl)-methanol. To a -20 C. solution of n-butyllithium (2.5 M in hexane, Aldrich, 26.5 mmol) in dry tetrahydrofuran (200 mL) under argon was added 2,2,6,6-tetramethylpiperidine (Aldrich, 11.5 mL, 66.5 mmol, 1.22 eq). The resulting solution was warmed to 0 C. over 0.5 hour period. The solution was then cooled to -78 C., and a solution of 2,6-dichloropyrazine (Aldrich, 8.24 g, 55.3 mmol, 1.0 eq) in tetrahydrofuran was slowly added via a syringe. After addition was complete, the resulting mixture was stirred at -78 C. for an additional 1 hour after which 2-chlorobenzaldehyde (Aldrich, 9.3 mL, 83 mmole, 1.5 eq) was added drop wise via a syringe. The reaction mixture was stirred for an additional 1 hour, quenched with hydrochloric acid (18 mL, 220 mmol, 4 eq)/ethanol (75 mL)/tetrahydrofuran (90 mL) mixture, and then warmed to room temperature. The reaction mixture was diluted with aqueous saturated sodium bicarbonate solution and extracted with ether. The organic layer was separated and washed with brine, dried over sodium sulfate, filtered, and concentrated to give a crude oil which was purified via chromatography using dichloromethane/hexanes (1:1) as the eluent to give (2-chlorophenyl)-(3,5-dichloropyrazin-2-yl)methanol (12.8 g, 44 mmol, 80% yield). Mass spec M+1=290.

Statistics shows that 2,6-Dichloropyrazine is playing an increasingly important role. we look forward to future research findings about 4774-14-5.

Reference:
Patent; Arora, Nidhi; Billedeau, Roland Joseph; Dewdney, Nolan James; Gabriel, Tobias; Goldstein, David Michael; O’Yang, Counde; Soth, Michael; US2005/197340; (2005); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem