Pyrazines

Application of 54608-52-5, A common heterocyclic compound, 54608-52-5, name is 2-Hydrazinopyrazine, molecular formula is C4H6N4, 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.

To a stirred reaction mixture of 2-hydrazinopyrazine (8)(14.0 g, 0.127 mol) and sodium carbonate (16.2 g, 0.153 mol)in dichloromethane (DCM) (112 mL), the solution of trifluoroacetylchloride (18.5 g, 0.14 mol) in DCM (28 mL) wasadded slowly at 0-5 C. The reaction mixture was agitated at5-10 C until completion of the reaction that was judged byTLC. Water (140 mL) was added to the reaction mass toremove water soluble components and then it was allowedto stand to attain the partition between DCM and water.The organic layer was concentrated under atmospheric conditionsat below 45 C. The crude residue was recrystallizedfrom mixture of EtOAc:hexane to obtain 2,2,2-trifluoro-N’-(pyrazin-2-yl)acetohydrazide (9) as off-white solid (22.5 g,86.5%). 1H NMR (400 MHz; CD3OD), d, ppm (J, Hz): 7.94-8.22 (2H, m, Ar-H); 7.66 (1H, s, Ar-H). ESI-MS m/z (rel,%): 207.12 (M+H+) (100).

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:
Article; Mannam, Madhava Rao; Devineni, Subba Rao; Pavuluri, Chandra Mouli; Chamarthi, Naga Raju; Kottapalli, Raja Sekhara P.; Phosphorus, Sulfur and Silicon and the Related Elements; vol. 194; 9; (2019); p. 922 – 932;,
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. 63286-28-2, name is 2-Chloro-3-hydrazinylpyrazine, This compound has unique chemical properties. The synthetic route is as follows., Product Details of 63286-28-2

Intermediate B-1 (15.6 g; 108 mmol) is slurried up in THF (300 ml_) and cooled down in an ice bath to – 5 C. Trifluoroacetic anhydride (17 ml118 mmol) is also dissolved in 300 ml_ THF and dropped slowly to the first solution. After 1 h most of the THF is evaporated, then a small amount of water is added and the mixture is extracted with DCM. The organic phase is dried over MgS04 and evaporated to dryness. (0283) Yield: 100 % HPLC-MS: (M+H)+ = 241/243; tRet = 1.31 min; method FSUN2

According to the analysis of related databases, 63286-28-2, the application of this compound in the production field has become more and more popular.

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

Adding a certain compound to certain chemical reactions, such as: 6966-01-4, name is Methyl 3-amino-6-bromopyrazine-2-carboxylate, 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 6966-01-4, Formula: C6H6BrN3O2

Step 2; A suspension of compound 2 (28.5 g, 120 mmol) in an aqueous solution of 48% HBr (120 mL) and acetic acid (30 mL) was cooled to 0 C., and then treated with a solution of bromine (18 mL, 336 mmol) in acetic acid (18 mL) over a period of 45 min. A solution of NaNO2 (8.28 g, 420 mmol) in water (15 ml) was added while maintaining the temperature at 0 C., stirring was continued for further 30 min. After completion of reaction (reaction progress was monitored by TLC), the excess bromine was quenched by the drop wise addition of 30% aqueous solution of NaHSO3 (180 mL). The resulting precipitate was filtered and purified by column chromatography on silica gel eluted with 10% ethyl acetate in hexane to afford compound 3 as a white crystalline solid (18 g, 49%). MS m/z (ES): 294 (M+H)+.

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-amino-6-bromopyrazine-2-carboxylate, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; de Vicente Fidalgo, Javier; Hermann, Johannes Cornelius; Lemoine, Remy; Li, Hongju; Lovey, Allen John; Sjogren, Eric Brian; Soth, Michael; US2011/59118; (2011); 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. 59489-71-3, name is 2-Amino-5-bromopyrazine, A new synthetic method of this compound is introduced below., Computed Properties of C4H4BrN3

Sodium nitrite (0.54 g, 7.53 mmol) was added portionwise to concentrated H2SO4 (3.8 mL) at 0 C. The mixture was heated at 50 C. until all of the NaNO2 had dissolved and the mixture was again cooled to 0 C. A solution of 2-amino-5-bromopyrazine (1 g, 5.57 mmol) in concentrated H2SO4 (5.8 mL) was added dropwise to the nitronium solution. The ice bath was removed, and the mixture was warmed to ambient temperature and stirred for 15 minutes, then heated to 45 C. for 10 minutes. The mixture was cooled to ambient temperature and poured onto ice water (40 mL). The pH was adjusted to about 4 with 2N NaOH. The mixture was extracted with EtOAc (60 mL×3). The combined organic extracts were washed with water, brine, dried over Na2SO4, filtered, and the filtrate was concentrated to a yellow solid, which was triturated with hexanes to give 0.664 g (68%) of 5-bromo-2-pyrazinol (and tautomers thereof) as a yellow solid. 1H NMR (400 MHz, CDCl3): delta 8.07 (s, 1H), 7.62 (s, 1H); LRMS (ESI), m/z 175/177 (M+H).

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; SMITH KLINE BEECHAM CORPORATION a corporation; US2010/29650; (2010); 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. 59489-71-3, name is 2-Amino-5-bromopyrazine, A new synthetic method of this compound is introduced below., Quality Control of 2-Amino-5-bromopyrazine

EXAMPLE 41B 5-Bromo-2-iodopyrazine Under N2, to the mixture of the product of Example 41A (7.50 g, 43 mmol) in DME (anhydrous, Aldrich, 200 mL) was added CsI (Aldrich, 11.20 g, 43 mmol), iodine (Aldrich, 5.52 g, 21.6 mmol), CuI (Stream, 2.52 g, 13.2 mmol) and isoamyl nitrite (34.8 mL, 259.2 mmol) at ambient temperature. It was then heated to 60 C. and stirred for 30 min. till no gas evolution was observed. After being cooled down to room temperature, the dark mixtures was poured into a flask containing EtOAc (200 mL) and saturated NH4Cl (200 mL), stirred for 10 min. The organic layer was separated and the aqueous layer was extracted with EtOAc (2*1000 mL). The combined organic solution was washed with 5% of Na2S2O3 aqueous (2*50 mL), brine (50 mL) and dried over MgSO4. The drying agents were filtered off and the organic solution was concentrated to provide the title compound. 1H NMR (300 MHz, CDCl3) delta 8.50 (d, J=1.36 Hz, 1H), 8.62 (d, J=1.36 Hz, 1H) ppm; m/z 284 (M+H)+, 286 (M+H)+.

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; Ji, Jianguo; Li, Tao; Lynch, Christopher L.; Gopalakrishnan, Murali; US2008/45539; (2008); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Related Products of 16298-03-6, A common heterocyclic compound, 16298-03-6, name is Methyl 2-aminopyrazine-3-carboxylate, molecular formula is C6H7N3O2, 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) Methyl 2-bromo-3-pyrazine carboxylate: To a stirred mixture of 12.7 g. of methyl 2-aminopyrazine 3-carboxylate and 47 ml. of 48percent hydrobromic acid there is added, dropwise, 12.6 ml. of bromine keeping the temperature at 0°. A solution of 14.4 g. of sodium nitrite in 60 ml. of water is then added, dropwise, at 0° and the reaction mixture stirred for 15 minutes. The reaction mixture is basified to pH 8 with sodium bicarbonate and extracted with ethyl acetate and again with chloroform. The organic layers are dried over magnesium sulfate, filtered and concentrated to a yellow oil. Recrystallization from ether-hexane yields the product, m.p. 43°-45° C.

The synthetic route of 16298-03-6 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Schering Corporation; US4551463; (1985); A;,
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. 5049-61-6, name is Pyrazin-2-amine, A new synthetic method of this compound is introduced below., COA of Formula: C4H5N3

To a solution of pyrazin-2-ylamine (2. 0 g, 21. 03 mmol) in dry DICHLOROMETHANE (120 mL) at 0 C, was added N-BROMOSUCCINIMIDE (3. 74 g, 21. 03 mmol) slowly to maintain the internal temperature below 0 C. The mixture was stirred at the same temperature for 24 hours, and then washed with saturated aqueous sodium bicarbonate (30 mL) and water (30 mL). The combined aqueous extracts were extracted with DICHLOROMETHANE (3 x 100 mL). The combined organic extracts were dried (anhydrous magnesium sulfate), filtered, and concentrated in vacuo to afford the crude product. The residue was purified by flash column chromatography (10% to 50% ethyl acetate/hexanes) to yield the title compound (2. 57 g, 70%) as a yellow solid. LRMS (m/z) : 174 (M)-. ‘H NMR (CDCI3, 300 MHz) : 8. 08 (1H, d, J= 1. 3 Hz), 7. 76 (1H, D, J= 1. 3 Hz).

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; PFIZER INC.; WO2004/92145; (2004); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Related Products of 91476-80-1, These common heterocyclic compound, 91476-80-1, name is 5,6,7,8-Tetrahydroimidazo[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.

(6) A mixture of whole amount of 4-(3-chloro-4-methoxybenzylamino)-5-methoxycarbonyl-6-(4-hydroxypiperidin-1-yl)-2-methylsulfinylpyrimidine (prepared in the above (5)), 5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine 73 mg, triethylamine 0.083 ml and N,N-dimethylacetamide 4 ml is stirred at 110 C. for 4 hours. After cooling the reaction mixture is diluted with a 10% aqueous citric acid solution and washed with ethyl acetate. The organic layer is extracted with a 10% aqueous citric acid solution. The water layer is made basic with sodium hydrogen carbonate and extracted with ethyl acetate. The ethyl acetate layer is washed, dried and concentrated in vacuo. The residue is separated with silica gel chromatography (solvent; chloroform_methanol=100:1?50:1), and then crystallized from a mixture of ethyl acetate, methanol and isopropyl ether to give 4-(3-chloro-4-methoxybenzylamino)-5-methoxycarbonyl-6-(4-hydroxypiperidin-1-yl)-2-(5,6,7,8-tetrahydroimidazo[1,2-a]pyrazin-7-yl)pyrimidine as a colorless crystalline powder 20 mg. mp 179-180 C. IR (Nujol)cm-1: 3380, 3181, 1664, 1572, 1533, 1463 APCI-MS(m/z): 528(M+H)+

The synthetic route of 91476-80-1 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Yamada, Koichiro; Matsuki, Kenji; Omori, Kenji; Kikkawa, Kohei; US2004/142930; (2004); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Application of 50866-30-3, 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. 50866-30-3, name is 5-Methylpyrazine-2-carbaldehyde, This compound has unique chemical properties. The synthetic route is as follows.

To the starting material 5-methylpyrazine-2-carbaldehyde (100 mg, 0.8 mmol), THF (1.0mL) was added followed by phosphorene 8 (250 mg 1.7 mmol) at room temperature. Thereaction mixture was stirred for 8 h at 60 C. TLC revealed complete consumption ofstarting material. The reaction mixture was removed from heating bath and quenchedusing a saturated aqueous NH4Cl solution. Water (10 mL) and ethyl acetate (25 mL) wereadded, layers were separated washed with brine solution, dried over sodium sulfate andevaporated under reduced pressure to dryness. Then column purification was done to getthe pure product which was characterized by NMR. Yield: 72%

The chemical industry reduces the impact on the environment during synthesis 5-Methylpyrazine-2-carbaldehyde. I believe this compound will play a more active role in future production and life.

Reference:
Article; Balasubramaniam, Sivaraman; Vijayan, Sajith; Goldman, Liam V.; May, Xavier A.; Dodson, Kyra; Adhikari, Sweta; Rivas, Fatima; Watkins, Davita L.; Stoddard, Shana V.; Beilstein Journal of Organic Chemistry; vol. 16; (2020); p. 628 – 637;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Adding a certain compound to certain chemical reactions, such as: 87597-21-5, name is Ethyl 6,8-dibromoimidazo[1,2-a]pyrazine-2-carboxylate, 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 87597-21-5, Application In Synthesis of Ethyl 6,8-dibromoimidazo[1,2-a]pyrazine-2-carboxylate

To a stirred solution of ethyl 6,8-dibromoimidazo[1,2-a]pyrazine-2-carboxylate (13.95 g, 40 mmol) in toluene (558 mL) at 0 C. was added 80 mL DIBAH (120 mmol, 3 eq, 1.5M in toluene) dropwise. After stirring overnight at rt, the solution was poured on 1M HCl, extracted with ethyl acetate and the organic phase was washed with water, sole, dried over sodium sulphate and filtered. Removal of the solvent and recrystallyzation from DCM yielded 5.55 g (45.2%) (6,8-dibromoimidazo[1,2-a]pyrazin-2-yl)methanol: 1H-NMR (300 MHz, d6-DMSO): delta=8.93 (s, 1H), 8.05 (s, 1H), 5.46 (bs, 1H), 4.63 (s, 2H) ppm. UPLC-MS: RT=0.73 min; m/z 308.0 [MH+]; required MW=307.0.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, Ethyl 6,8-dibromoimidazo[1,2-a]pyrazine-2-carboxylate, and friends who are interested can also refer to it.

Reference:
Patent; BAYER INTELLECTUAL PROPERTY GMBH; Koppitz, Marcus; Klar, Ulrich; Jautelat, Rolf; Kosemund, Dirk; Bohlmann, Rolf; Bader, Benjamin; Lienau, Philip; Siemeister, Gerhard; US2013/267527; (2013); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem