Category: Pyrazines

24241-18-7, Adding some certain compound to certain chemical reactions, such as: 24241-18-7, name is 2-Amino-3,5-dibromopyrazine, 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 24241-18-7.

The suspension of 18b (2.51 g, 10.0 mmol), NaCN (0.59 g,12.0 mmol), CuI (0.95 g, 5.0 mmol) and Pd(PPh3)4 (0.14 g,0.1 mmol) were stirred in DMF (20 mL) at 120 C for 10 h under nitrogen protection. After cooling to room temperature, 10% aqueous solution of Na2S2O3(10 mL) and water(50 mL) were added. The mixture was extracted with ethyl acetate (50 mL ¡Á 3), washed with water (3 ¡Á 50 mL), dried over anhydrous Na2SO4 and concentrated. The residue was purified by chromatography on silica gel eluting with PE/EA (10:1-2:1) to give an off-white solid (1.1 g, yield 55%). 6-Bromo-3-aminopyrazine-2-carbonitrile (19b)Yield: 55%, off-white solid, M.p.: 180-182 C (Lit.183-184 C, Sato et al. 1990a, b). 1H NMR (400 MHz,DMSO-d6): delta 8.45 (s, 1H), 7.62 (s, 2H). 1H NMR (400 MHz,CDCl3):delta 8.30 (s, 1H), 5.28 (s, 2H). 13C NMR (125 MHz,DMSO-d6): delta 156.70, 150.49, 123.64, 115.45, 110.60. EI-MS m/z: 198 (M+, Br79,100), 200 (M+, Br81,98), 171(M+, Br79,-H, -CN, 17), 173 (M+, Br81,-H, -CN, 17),119(M+, -Br, 32), 92 (M+, -Br, -H, -CN, 46).

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 24241-18-7.

Reference:
Article; Guo, Qi; Xu, Mingshuo; Guo, Shuang; Zhu, Fuqiang; Xie, Yuanchao; Shen, Jingshan; Chemical Papers; vol. 73; 5; (2019); p. 1043 – 1051;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

873-40-5, 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. 873-40-5, name is 2,3,5-Trichloropyrazine, This compound has unique chemical properties. The synthetic route is as follows.

General procedure: Under nitrogen gas stream 2,3,5-trichloropyrazine of 28g (152.65mmol),2-chlorophenylboronic acid of 23.8g (152.65mmol),Put THF / H2O and K2CO3 of 800ml / 200ml 63.3g (457.9mmol) and stirred. At 40 into the Pd (PPh3) 4 of 5.3g (4.58mmol) was stirred at 80 for 12 hours.After completion of the reaction, which was then extracted with dichloromethane. The organic layer was dried over MgSO4 filtered under reduced pressure. The filtered organic layer was evaporated under reduced pressure to a back by column chromatography the desired compound 2,5-dichloro-3- (2-chlorophenyl) pyrazine 12g (yield: 30%) was obtained.

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; Doosan Corporation; Kim, Tae Hyung; Bae, Hyung Chan; Son, Hyo Suk; Baek, Young Mi; Patk, Ho Chul; (54 pag.)KR101488560; (2015); B1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

123-32-0, Name is 2,5-Dimethylpyrazine, 123-32-0, 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.

To the ethyl acetate solution (7 ml) of 2,5-dimethylpyrazine (500 mg, 5.36 mmol) at room temperature, m-chloroperbenzoic acid (1.27 g, 7.36 mmol) was added and stirred for 24 hours did. Thereafter, the reaction system was filtered and the solid was washed with ethyl acetate to obtain 2,5-dimethylpyrazine-N, N’-dioxide. Yield 517 mg, yield 80%, white solid

Statistics shows that 2,5-Dimethylpyrazine is playing an increasingly important role. we look forward to future research findings about 123-32-0.

Reference:
Patent; NIPPON STEEL & SUMIKIN CHEMICAL COMPANY LIMITED; KYUSHU INSTITUTE OF TECHNOLOGY; NAGAHAMA, TAKUO; KAWADA, ATSUSHI; TAKASHIMA, WATARU; OKAUCHI, TATSUO; NAGAMATSU, SHUICHI; (69 pag.)JP2017/178911; (2017); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

767340-03-4, name is (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine, 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. 767340-03-4

Into a 500 ml flask were charged chloro(l,5-cyclooctadiene)rhodium(I) dimer {[Rh(cod)Cl]2}(292 mg, 1.18 mmol) and (R,S) f-butyl Josiphos (708 mg, 1.3 mmol) under a nitrogen atmosphere. Degassed MeOH was then added (200 mL) and the mixture was stirred at room temperature for 1 h. Into a 4 L hydrogenator was charged the enamine amide 2Lambda (118 g, 0.29 mol) along with MeOH (1 L). The slurry was degassed. The catalyst solution was then transferred to the hydrogenator under nitrogen. After degassing three times, the enamine amide was hydrogenated under 200 psi hydrogen gas at 50 0C for 13 h. Assay yield was determined by EtaPLC to be 93% and optical purity to be 94% ee.The optical purity was further enhanced in the following manner. The methanol solution from the hydrogenation reaction (18 g in 180 mL MeOH) was concentrated and switched to methyl t- butyl ether (MTBE) (45 mL). Into this solution was added aqueous Eta3PO4 solution (0.5 M, 95 mL).After separation of the layers, 3NNaOH (35 mL) was added to the water layer, which was then extracted with MTBE (180 mL + 100 mL). The MTBE solution was concentrated and solvent switched to hot toluene (180 mL, about 75 0C). The hot toluene solution was then allowed to cool to 0 0C slowly (5 – 10 h). The crystals were isolated by filtration (13 g, yield 72%, 98 – 99% ee); m.p. 114.1 – 115.7 0C. lH NMR (300 MHz, CD3CN): delta 7.26 (m), 7.08 (m), 4.90 (s), 4.89 (s), 4.14 (m), 3.95 (m), 3.40 (m), 2.68(m), 2.49 (m), 1.40 (bs).Compound 2-5 exists as amide bond rotamers. Unless indicated, the major and minor rotamers are grouped together since the carbon-13 signals are not well resolved: 13c NMR (CD3CN): delta 171.8, 157.4 (ddd , JCF = 242.4, 9.2, 2.5 Hz), 152.2 (major), 151.8 (minor), 149.3(ddd; JCF = 246.7, 14.2, 12.9 Hz), 147.4 (ddd, JCF = 241.2, 12.3, 3.7 Hz), 144.2 (q, JCF = 38.8 Hz), 124.6 (ddd , JCF = 18.5, 5.9, 4.0 Hz), 120.4 (dd , JCF = 19.1, 6.2 Hz), 119.8 (q, JCF = 268.9 Hz), 106.2 (dd , JCF = 29.5, 20.9 Hz), 50.1, 44.8, 44.3 (minor), 43.2 (minor), 42.4, 41.6 (minor), 41.4, 39.6, 38.5 (minor), 36.9. The crystalline free base 2^ can also be isolated as follows:(a) The reaction mixture upon completion of the hydrogenation step is charged with 25 wt% of Ecosorb C-941. The mixture is stirred under nitrogen for one h and then filtered. The cake is washed with 2L/kg of methanol. Recovery of free base is about 95% and optical purity about 95% ee.(b) The freebase solution in methanol is concentrated to 3.5-4.0 L/kg volume (based on free base charge) and then solvent-switched into isopropanol (IPA) to final volume of 3.0 L/kg IPA.(c) The slurry is heated to 40 0C and aged 1 h at 4O0C and then cooled to 25 0C over 2 h. EPO (d) Heptane (7L/kg) is charged over 7 h and the slurry stirred for 12 h at 22-250C. The supernatant concentration before filtering is 10-12 mg/g.(e) The slurry is filtered and the solid washed with 30% IPA/heptane (2L/kg).(f) The solid is dried in a vacuum oven at 40 0C. (g) The optical purity of the free base is about 99% ee.

Statistics shows that 767340-03-4 is playing an increasingly important role. we look forward to future research findings about (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine.

Reference:
Patent; MERCK & CO., INC.; WO2006/33848; (2006); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

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 63744-22-9 as follows. 63744-22-9

General procedure: 6,8-dibromoimidazo[1,2-a]pyrazine (6, 1.86 g, 6.72 mmol) was added to asolution of 3a-3c, 5a-5e (5.6 mmol), DIPEA (1.4 mL, 8.4 mmol) inisopropanol (60 mL), stirred at 85 C for 8 h, and then the solvent wasevaporated to dryness. The crude product was purified by columnchromatography to obtain the desired intermediates 7a, 11a-11 g.

According to the analysis of related databases, 63744-22-9, the application of this compound in the production field has become more and more popular.

Reference:
Article; Fan, Yan; Huang, Zhi; Li, Yao; Qin, Zhongxiang; Wang, Cheng; Wang, Tianqi; Wang, Xin; Xiang, Rong; Yang, Shengyong; Bioorganic Chemistry; vol. 95; (2020);,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

15707-23-0, 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 15707-23-0 as follows.

Ag2O (23.2 mg, 0.1 mmol), 3-nitro-1,2-benzenedicarboxylicacid (H2npt) (42.2 mg, 0.2 mmol) and epyz (24.4 mg, 0.2 mmol) were dissolved in methanol-H2O-DMF mixed solvent (6 mL,v/v/v = 1/1/1) in the presence of ammonia (0.5 mL, 14 M) underultrasonic treatment (160 W, 40 kHz, 30 min) under 40 C. Theresultant colorless solution was allowed slowly to evaporate atroom temperature in the dark. After several days, colorless platecrystals of 1 were isolated in about a 43% yield. They were washedwith a small volume of cold ethanol. Anal. Calc. for Ag2C15H13N3O6:C, 32.94; H, 2.40; N, 7.68. Found: C, 32.98; H, 2.38; N, 7.72%. IR(KBr): m (cm1) = 3440 (m), 3088 (w),3046 (w), 2976 (m),2932(w), 2876 (w), 1590 (s), 1520 (s), 1457(s), 1408 (s), 1344 (s),1288 (m), 1162 (m), 1027 (w), 929 (m), 859 (m), 824 (m), 782(w), 747 (w), 704 (m), 683 (m), 586 (w).

According to the analysis of related databases, 2-Ethyl-3-methylpyrazine, the application of this compound in the production field has become more and more popular.

Reference:
Article; Zhang, Ting; Wang, Dan-Feng; Huang, Rong-Bin; Zheng, Lan-Sun; Inorganica Chimica Acta; vol. 427; (2015); p. 299 – 304;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

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. 36070-80-1 name is 5-Chloropyrazine-2-carboxylic acid, 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. 36070-80-1

General procedure: The corresponding substituted salicylanilide 2 (1 mmol) and 5-chloropyrazine-2-carboxylic acid 1 (1 mmol) were dissolved in dryDMF (8 mL), the solution was cooled to 10 C and DCC (1.2 mmol)was added in three portions during 1 h. The mixture was stirred foradditional 3 h at the same temperature and then stored at 4 C for20 h. The precipitate of N,N0-dicyclohexylurea was removed byfiltration and the solvent was evaporated in vacuo till dryness. Thecrude products 3 were purified by one or repeated crystallizationfrom ethyl acetateehexane mixture.

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

Reference:
Article; Baranyai, Zsuzsa; Kratky, Martin; Vin?ova, Jarmila; Szabo, Nora; Senoner, Zsuzsanna; Horvati, Kata; Stola?ikova, Ji?ina; David, Sandor; Bosze, Szilvia; European Journal of Medicinal Chemistry; vol. 101; (2015); p. 692 – 704;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

875781-43-4, A common heterocyclic compound, 875781-43-4, name is 2-Bromo-5H-pyrrolo[2,3-b]pyrazine, molecular formula is C6H4BrN3, 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.

Preparation of 2-bromo-7-iodo-5H-pyrr lo [3,2-6] yrazine (Intermediate AT)[0316] To a solution of 2-bromo-5H-pyrrolo[3,2-?]pyrazine [Intermediate AS] (0.68 g, 3.4 mmol) in acetone (17 mL) was added N-iodosuccinimide (0.82 g, 3.6 mmol) and the resulting mixture was stirred for 4 h at rt. The mixture was evaporated in vacuo to yield a residue that was purified via silica gel chromatography eluting with 40% THF in hexanes to give the title compound as a yellow solid (0.99 g, 89%). 1H NMR (DMSO-dtf, 300 MHz): delta 12.82 (s, 1H), 8.42 (s, 1 H), 8.20 (s, 1 H). HPLC retention time: 2.23 minutes. MS ESI (m/z): 324.0, 326.0 (M+H)+, calc. 323.

The synthetic route of 875781-43-4 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; UNIVERSITY OF ROCHESTER; GELBARD, Harris, A.; DEWHURST, Stephen; GOODFELLOW, Val, S.; WIEMANN, Torsten; RAVULA, Satheesh, Babu; LOWETH, Colin, J.; WO2011/149950; (2011); A2;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

6164-79-0, Name is Methyl 2-pyrazinecarboxylate, 6164-79-0, 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.

d Pyrazine-2-hydrazide To a solution of the product from Example 1 step c) (22 g, 159 mmol) in methanol (250 ml) was slowly added hydrazine monhydrate (36.6 ml, 710 mmol). The reaction mixture was stirred for 1.5 h. The precipitate produced was filtered, washed with diethyl ether and dried in the oven at 80 C. to give the required product (30 g). 1H NMR (250 MHz, DMSO) delta 4.66 (2H, broad peak), 8.66 (1H, m), 8.84 (1H, d, J=2.5 Hz), 9.13 (1H, d, J=2.5 Hz), 10.15 (1H, broad peak); MS (ES+) m/e 139 [MH+].

Statistics shows that Methyl 2-pyrazinecarboxylate is playing an increasingly important role. we look forward to future research findings about 6164-79-0.

Reference:
Patent; Merck Sharp & Dohme Ltd.; US6297235; (2001); B1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

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. 767340-03-4, name is (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine, This compound has unique chemical properties. The synthetic route is as follows., 767340-03-4

Ligand Metal precursor percentyieldb percent eec config. 15 3 A [Rh(cod) 2]BF4 77 88 R 4 B [Rh(cod)Cl]2 58 76 R 5 C [Rh(cod)Cl]2 15 78 a: Reaction conditions: in TFE, 5 molpercent metal precursor, 5 molpercent ligand, 90 psig H2, 50 ¡ãC, 18 h; b: Assayed by HPLC; c: Assayed by chiral HPLC using a AS-RH chiral column eluting with 20percent acetonitrile/water as the mobile phase.

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; MERCK & CO., INC.; SOLVIAS AG; WO2005/97733; (2005); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem