Tag: M.W=100-200

Electric Literature of 109838-85-9, A common heterocyclic compound, 109838-85-9, name is (R)-2-Isopropyl-3,6-dimethoxy-2,5-dihydropyrazine, molecular formula is C9H16N2O2, 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 B – Preparation of Compound Int-16cTo a 500 mL flame dried flask was added (R)-2-isopropyl-3, 6-dimethoxy-2,5- dihydropyrazine (10.0 g, 54.3 mmol) and anhydrous THF (200 mL). The solution was cooled to -78 ¡ãC. “-BuLi (2.5M in hexane, 24.0 mL, 59.7 mmol) was added dropwise. After the solution was allowed to stir at -78 ¡ãC for 30 minutes, compound Int-16b (in 5 mL anhydrous THF) was added dropwise. After the solution was allowed to stir at -78 ¡ãC for 1 hour, it was allowed to warm up to room temperature in two hours. Water (100 mL) and Et20 (150 mL) were added. The organic layer was separated and the aqueous layer was extracted with Et20 (100 mL) twice. The organic layers were combined, washed with brine, dried over Na2S04, filtered and concentrated in vacuo. The residue obtained was purified using Si02 chromatography (40 g, eluted with Et20 in Hexane: 0percent to 3percent) to provide compound Int-16c (10.43 g, 58.0percent).

The synthetic route of 109838-85-9 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; MERCK SHARP & DOHME CORP.; DWYER, Michael P; KEERTIKAR, Kartik M; COBURN, Craig A; WU, Hao; HU, Bin; ZHONG, Bin; ZHANG, Chengren; DAN, Zhigang; WO2012/40924; (2012); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Application of 32974-92-8, 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. 32974-92-8, name is 1-(3-Ethylpyrazin-2-yl)ethanone, This compound has unique chemical properties. The synthetic route is as follows.

General procedure: The ligands L1-L4 were synthesized by reflux method. Shown in Scheme 1, 5mM of 2-Acetyl-3-ethylpyrazine and thiosemicarbazides (L1), 5mM of 2-Acetyl-3-ethylpyrazine and 4-methylthiosemicarbazide (L2), 5mM of 2-Acetyl-3-ethylpyrazine and 4-phenylthiosemicarbazide (L3), and 5mM of 2-Acetyl-3-ethylpyrazine and 3-pyrrolethiosemicarbazide (L4) were stirred in CH3OH for 3 h at 65C. The ligands were precipitated and filtered. L1-L4 were characterized by infrared spectroscopy, electrospray ionization mass spectrometry (ESI-MS), 1H NMR, and 13C NMR (Supplementary Figs S4- S31).

The chemical industry reduces the impact on the environment during synthesis 1-(3-Ethylpyrazin-2-yl)ethanone. I believe this compound will play a more active role in future production and life.

Reference:
Article; Khan, Muhammad Hamid; Cai, Meiling; Li, Shanhe; Zhang, Zhenlei; Zhang, Juzheng; Wen, Xiaoan; Sun, Hongbin; Liang, Hong; Yang, Feng; European Journal of Medicinal Chemistry; vol. 182; (2019);,
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. 41110-29-6, name is Methyl 3-methylpyrazine-2-carboxylate, This compound has unique chemical properties. The synthetic route is as follows., HPLC of Formula: C7H8N2O2

In a 1 -L flask, the methyl 3-methylpyrazine-2- carboxylate (265A, 16.08 g, 106 mmol) was suspended in CHCl3 (300 mL). 3- Chlorobenzoperoxoic acid (Aldrich, 24.62 g, 143 mmol) was added. The reaction mixture was heated to 70 C for 16 h. The reaction mixture was quenched with saturated NaHCO3 (200 mL). The layers were separated, and the aqueous layer was further extracted with DCM (2 x 100 mL). The combined organic layers were dried over MgSO4, and the filtrate was concentrated to afford crude 3-(methoxycarbonyl)-2-methylpyrazine 1 -oxide (17.77 g). MS m/z=169 [M+H]+. In a 1 -L flask, the crude 3-(methoxycarbonyl)-2-methylpyrazine 1 -oxide (17.77 g, 106 mmol) was dissolved in DMF (300 mL). Neat phosphoryl trichloride (29.6 mL, 317 mmol) was added. The reaction mixture was heated to 100 C. After 1 h, the reaction mixture was concentrated to remove most of the DMF. The flask was cooled in an ice water bath, and 1 M aqueous Na2CO3 (300 mL) was added slowly, followed by 80% EtOAc-hexane (400 mL). The mixture was filtered through Celite filter aid. The resulting filtrate was partitioned and the aqueous phase was extracted further with 80% EtOAc-hexane (2 x 250 mL). The combined organic layers were dried over MgSO4 and concentrated. The material was purified through silica gel using 11 % EtOAc-hexane to afford methyl 5-chloro-3-methylpyrazine-2-carboxylate (265B, 4.29 g, 23 mmol, 22%). MS m/z=187 [M+H]+.

According to the analysis of related databases, 41110-29-6, the application of this compound in the production field has become more and more popular.

Reference:
Patent; AMGEN INC.; ALLEN, Jennifer R.; AMEGADZIE, Albert; BOURBEAU, Matthew P.; BROWN, James A.; CHEN, Jian J.; CHENG, Yuan; FROHN, Michael J.; GUZMAN-PEREZ, Angel; HARRINGTON, Paul E.; LIU, Longbin; LIU, Qingyian; LOW, Jonathan D.; MA, Vu Van; MANNING, James; MINATTI, Ana Elena; NGUYEN, Thomas T.; NISHMURA, Nobuko; NORMAN, Mark H.; PETTUS, Liping H.; PICKRELL, Alexander J.; QIAN, Wenyuan; RUMFELT, Shannon; RZASA, Robert M.; SIEGMUND, Aaron C.; STEC, Markian M.; WHITE, Ryan; XUE, Qiufen; (759 pag.)WO2016/22724; (2016); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Related Products 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.

A solution of 2-amino-5-cyanopyrazine (500.0 mg, 4.162 mmol) in 1,4- dioxane (8.3 ML) was treated with 4- (dimethylamino) pyridine (305.1 mg, 2.497 mmol), N, N, N’, N’-TETRAMETHYLETHYLENEDIAMINE (241.8 mg, 2.081 mmol), and di-tert-butyl dicarbonate (2.9 mL, 12.49 mmol). The reaction stirred at 25C for 20 h and then was concentrated in vacuo. Biotage chromatography (FLASH 40M, Silica, 10% ethyl acetate/hexanes) afforded 5- [ [BIS [ (L, 1-dimethylethoxy) carbonyl] ] amino]-2- pyrazinecarbonitrile as a white solid: mp 67-68C ; (ES) +-HRMS m/e calcd for CISH2ON404 (M+Na) + 343. 1377, found 343.1379.

The synthetic route of 113305-94-5 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; F. HOFFMANN-LA ROCHE AG; WO2004/52869; (2004); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Related Products of 21943-12-4,Some common heterocyclic compound, 21943-12-4, name is 2-Amino-3-bromopyrazine, molecular formula is C4H4BrN3, 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.

General procedure: Step 1: A vial equipped with a magnetic stir bar was charged with the ortho-haloaminopyridine and BrettPhos G1 precatalyst (6 mol %). The vial was sealed with a teflon screw cap, and evacuated and backfilled with argon three times. The amine (1 to 1.5 mol eq) was added via syringe, followed by LiHMDS solution (1M in THF, 2.5 mol eq). Amines that were solid at room temperature were added with the catalyst. The reaction mixture was stirred at 40 C for 4-18 h, until LC/MS indicated complete conversion of the starting material. The mixture was cooled to room temperature, diluted with dichloromethane, and poured into water. The organic phase was separated and the aqueous phase was extracted twice more with dichloromethane. The combined organic phases were dried over Na2SO4. The solvent was removed under reduced pressure.

The synthetic route of 21943-12-4 has been constantly updated, and we look forward to future research findings.

Reference:
Article; Li, Chaomin; Chen, Lily; Steinhuebel, Dietrich; Goodman, Andrew; Tetrahedron Letters; vol. 57; 25; (2016); p. 2708 – 2712;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Synthetic Route of 98-97-5, The chemical industry reduces the impact on the environment during synthesis 98-97-5, name is Pyrazine-2-carboxylic acid, I believe this compound will play a more active role in future production and life.

Step 1 (esterification of pyrazine-2-carboxylic acid to yield methyl-pyrazine-2-carboxylate): To a 1L single-neck round-bottomed flask fitted with condenser and drying tube filled with silica gel was charged methanol (400 mL) with agitation at room temperature. Pyrazine-2-carboxylic acid (50.00 g, 402.90 mmol) was charged to the flask in one portion and the resulting slurry was vigorously stirred. Conc. sulfuric acid (0.25 mL) was charged to the slurry. The slurry was heated to reflux temperature and stirred at this temperature for 2 days. The resulting pale yellow solution was allowed to cool to room temperature. This process takes 90 minutes. Solid sodium bicarbonate (4.00 g, 47.62 mmol) was added to the solution in one portion and the slurry was stirred vigorously for 30 minutes. The suspension was filtered and the filtrate was transferred to a 2L single-neck round-bottomed flask and concentrated to about half volume in vacuo a 35 C. Toluene (1200 mL) was added to the methanol solution and a Dean-Stark trap fitted with drying tube was attached. The solution was heated at atmospheric pressure (external oil bath a120 C.) and the first 300 mL solvent fraction was run off and discarded. The Dean-Stark trap was removed and the reaction solution was concentrated in vacuo a45 C. to a volume of 300 mL. The organic phase containing the desired methyl-pyrazine-2-carboxylate was filtered to remove solid particulates and used directly in the next step as a solution in toluene (a small analytical sample was removed and concentrated in vacuo a 35 C. to yield a pale brown solid, m.p. 60-61 C., structure confirmed by 1H NMR and 13C NMR).

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, Pyrazine-2-carboxylic acid, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; Patrick Prendergast; US2004/53989; (2004); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Related Products of 75907-74-3, These common heterocyclic compound, 75907-74-3, name is (3,5,6-Trimethylpyrazin-2-yl)methanol, 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.

(4) In a round bottom flask, add formula (4) (1.0 equiv), using DCM as solvent.Add phosphorus tribromide (1.0-2.0 equiv) at 0 C, stir the reaction at 25 C for 1 h, TLC monitoring formula (4) disappeared, after the reaction was completed, water was added, dichloromethane was extracted, and the organic layer was collected.Drying and concentrating gave the compound of the formula (5) as a white solid.

Statistics shows that (3,5,6-Trimethylpyrazin-2-yl)methanol is playing an increasingly important role. we look forward to future research findings about 75907-74-3.

Reference:
Patent; Chengdu University; Zou Liang; Zhang Jinming; Li Junlong; Liu Xiaowei; Li Wei; Shen Xudong; Dai Liping; Zhuo Hongyi; (13 pag.)CN108440512; (2018); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

6905-47-1, name is 2-Amino-6-methoxypyrazine, 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. Quality Control of 2-Amino-6-methoxypyrazine

The 3-amino-2-chloro-5-methoxypyrazine used as a starting material were prepared asfollows :-N-Chlorosuccinimide (1.7 g) was added portionwise to a solution of 2-amino-6-methoxypyrazine (S K Vohra et al, J. Org. Chem., 1979,44,1128; 1.6 g) in chloroform(26 ml) and the resultant mixture was stirred at ambient temperature for 3 hours. Silica gel(10 g) was added and the solvents were evaporated. The residue was purified by columnchromatography on silica gel using methylene chloride as eluent. There were thus obtained inturn :- 2-amino-3,5-dichloro-6-methoxypyrazine (0.253 g); NMR Spectrum: (CDC13) 3.95(s, 3H), 4.83 (m, 2H); Mass Spectrum: M+ET1″ 194; a sample of 3-amino-2-chloro-5-methoxypyrazine that was contaminated with succinimide and 5-amino-2-chloro-3-methoxypyrazine (0.339 g); NMR Spectrum: (CDC13) 3.95 (s, 3H), 4.27 (m, 2H), 7.32(s, 1H); Mass Spectrum: M+H* 160. The fraction containing 3-amino-2-chloro-5-methoxypyrazine was purified further by column chromatography on silica gel eluting with a10:1 mixture of petroleum ether (b.p. 40-60C) and ethyl acetate. There was thus obtainedpurified material (0.94 g); NMR Spectrum: (CDC13) 3.87 (s, 3H), 4.82 (m, 2H), 7.36 (s, 1H);Mass Spectrum: M+H+ 160.

The synthetic route of 6905-47-1 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; ASTRAZENECA AB; ASTRAZENECA UK LIMITED; WO2004/108711; (2004); 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. 4774-14-5, name is 2,6-Dichloropyrazine, A new synthetic method of this compound is introduced below., category: Pyrazines

-Chloro-N-phenylpyrazin^-amine. 2,6-Dichloropyrazine (510 mg,3.4 mmol), palladium acetate (75 mg, 0.33 mmol), 4,5-bis(diphenylphosphino)-9,9- dimethylxanthene (405 mg, 0.7 mmol), potassium carbonate (4.6 g, 33.3 mmol), and aniline (0.3 mL, 3.3 mmol) were suspended in anhydrous dioxane (23 mL). The resulting mixture was degassed with nitrogen for 5 minutes and stirred at 9O0C for one hour. The reaction was partitioned between ethyl acetate and water. The aqueous layer was extracted with ethyl acetate (3 x 50 mL), and the organic layers were combined and dried over magnesium sulfate. After filtration, the solvent was removed in vacuo. The residue was purified by silica gel chromatography (0-60% ethyl acetate in hexanes) to give the title compound as a white solid (88 mg, 0.43 mmol, 13% yield); 1H NMR (DMSO-^6) delta 9.86 (s, IH), 8.17 (s, IH), 7.98 (s, IH), 7.63 (d, J= 10.0 Hz, 2H), 7.35 (t, J= 7.2 Hz, 2H), 7.03 (t, J= 6.8 Hz, IH); MS (ESI) MS (ESI) m/z 206.0 [M+ 1]+.

The synthetic route of 4774-14-5 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; SIGNAL PHARMACEUTICALS, LLC; WO2009/89042; (2009); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Adding a certain compound to certain chemical reactions, such as: 486460-21-3, name is 3-(Trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine, 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 486460-21-3, Product Details of 486460-21-3

In 100 mL of tetrahydrofuran,4.11 g (41 mmol) of triethylamine was added,6.60g (20mmol) of compound IV and4.81 g (25 mmol) of 3-trifluoromethyl-1,2,4-triazolo[4,3-a]pyrazine was refluxed for 1 hour.TLC monitors the progress of the reaction,After the reaction is completed,Concentrated under reduced pressure,Purified by column chromatography,That is, the product sitagliptin 7.90g (19.4mmol),The yield was 97%, HPLC purity = 99.88%.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 3-(Trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine, and friends who are interested can also refer to it.

Reference:
Patent; Shenzhen The Second People Hospital; Yan Dewen; Tan Hui; Zuo Xin; (8 pag.)CN109761988; (2019); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem