Month: March 2021

Electric Literature of 5049-61-6,Some common heterocyclic compound, 5049-61-6, name is Pyrazin-2-amine, molecular formula is C4H5N3, 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 2-aminopyrazine (4 g, 42.1 mmol) in dichloromethane (100 mL) was added NBS (18.7 g,105 mmol) in batches over a period of 1 h at room temperature. The reaction mixture was stirred at room temperaturefor 5 h. When the reaction was completed, saturated aqueous Na2CO3 solution (40 mL) was added. After stirring for 15 min, the mixture was partitioned between dichloromethane (200 mL) and water (100 mL). The organic layer wasthen dried over anhydrous Na2SO4, decolorized with activated charcoal (1 g), and concentrated to give a yellow solid(8.0 g, yield 76%). 2-Amino-3,5-dibromopyrazine (18b) Yield: 76%, yellow solid, M.p.: 112-114 C (Lit.113-114 C, Sato et al. 1990a, b). 1H NMR (400 MHz, DMSO-d6): delta 8.13 (s, 1H), 6.99 (s, 2H). 1H NMR (400 MHz,CDCl3):delta 8.04 (s, 1H), 5.09 (s, 2H). 13C NMR (125 MHz, CDCl3): delta 151.86, 143.06, 123.96, 123.65. ESI-MS m/z:249.2 [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 Pyrazin-2-amine, its application will become more common.

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

Synthetic Route of 768-05-8, In the next few decades, the world population will flourish. As the population grows rapidly and people all over the world use more and more resources, all industries must consider their environmental impact. 768-05-8, name is Pyrazinoic acid hydrazide belongs to Pyrazines compound, it is a common compound, a new synthetic route is introduced below.

General procedure: 2.3. General procedure for the synthesis of N’-(2r,4c-diaryl-3-azabicyclo[3.3.1]nonan-9-ylidene)pyrazine-2-carbohydrazide(8-14)The quest for the synthesis of N’-(2r,4c-diaryl-3-azabicyclo[3.3.1]nonan-9-ylidene)pyrazine-2-carbohydrazide (8-14) wasaccomplished in two steps as outlined in Scheme 1. A mixture of2r,4c-diaryl-3-azabicyclo[3.3.1]nonan-9-one (1-7) (1 mmol),commercially available pyrazine-2-carbohydrazide (PZH)(1.5 mmol) in methanol and chloroform mixture (1:1 v/v), andcatalytic amount of acetic acid (0.1 mL) was added and refluxed for2-3 h. On the completion of reaction, a solid mass was formed.After cooling to room temperature, the precipitate was filtered offand washed with cold mixture of ethanol and water. The crude product was recrystallized from ethanol [16].

The synthetic route of Pyrazinoic acid hydrazide has been constantly updated, and we look forward to future research findings.

Reference:
Article; Mangalam; Sebastian Antony Selvan; Sankar; Journal of Molecular Structure; vol. 1129; (2017); p. 305 – 312;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Application of 109-08-0, 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 109-08-0 as follows.

Step 1: 2-Chloromethylpyrazine To a solution of 2-methylpyrazine (4.7 g) in carbon tetrachloride (200 mL) were added N-chlorosuccinimide (8 g) and benzoyl peroxide (0.6 g). The mixture was brought to reflux with two 150-watt spotlights and irradiated for 4.5 hours. The mixture was then cooled to room temperature, evaporated to dryness, and chromatographed on flash silica gel using a mixture of ethyl acetate:toluene (1:4) as eluant to give the title compound as an oil, which was stored at 78¡ã C. as a solid. 1 H NMR (Ace-d6): delta 4.8 (2H, s), 8.6 (2H, s), 8.8 (1H, s).

According to the analysis of related databases, 109-08-0, the application of this compound in the production field has become more and more popular.

Reference:
Patent; Merck Frosst Canada, Inc.; US5389650; (1995); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Synthetic Route of 74290-67-8, In the next few decades, the world population will flourish. As the population grows rapidly and people all over the world use more and more resources, all industries must consider their environmental impact. 74290-67-8, name is 2-Amino-5-bromo-3-methylpyrazine belongs to Pyrazines compound, it is a common compound, a new synthetic route is introduced below.

To a solution of I-69 (300 mg, 0.6 mmol) in DMF (10 mL) are added I-87 (140 mg, 0.7 mmol), tetrakis(triphenylphosphine)palladium (0) (70 mg, 0.06 mmol) and 2M Na2CO3 (1.5 mL, 3.0 mmol). The mixture is heated to 100 C. for 1 hour in a microwave reactor. The mixture is cooled down and is extracted with H2O (20 mL) and EtOAc (30 mL). The combined organic layer is dried with MgSO4 and is filtered. The filtrate is concentrated and the residue is purified by silica gel flash column chromatography with 10% MeOH in CH2Cl2 as the eluent to afford the title compound (200 mg). Example 176-180, Table 1-the reaction is run at 120 C.Example 176-180, Table 1-the reaction is run at 120 C. [0509] Example 184-185, Table 1-the reaction is run at 120 C

The synthetic route of 2-Amino-5-bromo-3-methylpyrazine has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Boehringer Ingelheim International GmbH; BYLOCK, Lars Anders; US2013/195879; (2013); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reference of 24241-18-7, 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. 24241-18-7 name is 2-Amino-3,5-dibromopyrazine, 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.

3,5-Dibromopyrazin-2-amine (10.0 g, 39.5 mmol) was suspended in 200 ml concentrated (32%) aqueous ammonia and the mixture was stirred at 130 00 in a pressure tube for 5 days. The mixture was allowed to cool, forming a precipitate. Thesolid was collected by filtration, washed with water and dried in vacuo to give 5.10 g(27.0 mmol, 68% yield) of the title compound as a pale brown solid. Purity 100%.1H NMR (300 MHz, DMSO-d6) oe ppm 7.20 (s, 1 H), 6.40 (br s, 2H), 6.05 (br s, 2H).UPLC/MS (3 mm) retention time 0.69 mm.LRMS: mlz 189, 191 (M+1, lxBr).

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

Reference:
Patent; ALMIRALL, S.A.; AIGUADE BOSCH, Jose; CONNOLLY, Stephen; EASTWOOD, Paul Robert; ROBERTS, Richard Spurring; SEVILLA GOMEZ, Sara; CATURLA JAVALOYES, Juan Francisco; (110 pag.)WO2017/64068; (2017); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Synthetic Route of 32974-92-8, In the next few decades, the world population will flourish. As the population grows rapidly and people all over the world use more and more resources, all industries must consider their environmental impact. 32974-92-8, name is 1-(3-Ethylpyrazin-2-yl)ethanone belongs to Pyrazines compound, it is a common compound, a new synthetic route is introduced below.

(1) 2-acetyl-3-ethylpyrazine (420 ul, 3 mmol) was dissolved in methanol (20 ml).After dissolution,4-Benzyl-3-thiosemicarbazide (501 mg 3 mmol) was added.well mixed,The mixed solution was refluxed at 65 C for 4 h.filter,The filtrate evaporates at room temperature.There are pale yellow crystals,Filter again,Wash 2-3 times with absolute ethanol,Obtaining a ligand L5;

The synthetic route of 1-(3-Ethylpyrazin-2-yl)ethanone has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Guangxi Normal University; Yang Feng; Sun Zewen; Zhao Lei; Liang Hong; (16 pag.)CN109796501; (2019); A;,
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 762240-92-6 as follows. Product Details of 762240-92-6

The (R) – 3 – (tert-butoxycarbonylamino) – 4 – (2, 4, 5-trifluorophenyl) butanoic acid (26.6g), 2,6-dimethyl pyridine (18g) and 3 – (trifluoromethyl) – 5, 6, 7, 8-tetrahydro-[ 1, 2, 4] triazolo [4,3-a] pyrazine hydrochloride (17.3g) are sequentially added dichloromethane (300 ml) in, cooling to 0-5C, stirring, add TBTU (28.2g), natural recovery to the room temperature, to continue reaction 8-10 hours. After the reaction, the organic phase for sequentially 1NHCl (200 ml), water (200 ml), 5% sodium carbonate aqueous solution (200 ml), saturated aqueous sodium chloride solution (200 ml) washing, dry anhydrous sodium sulfate, filtered, concentrated under reduced pressure, to obtain white foam solid 36g, yield 90%. 1 HNMR (400MHz, CDCl 3) delta 1.39 (s, 9H), 2.59-2.72 (m, 2H), 2.79-2.96 (m, 2H), 3.96-4.38 (m, 5H), 4.95 (s, 1H), 4.98-5.10 (m, 1H), 5.31 (b, 1H), 6.89-6.93 (m, 1H), 6.97-7.06 (m, 1H).

According to the analysis of related databases, 762240-92-6, the application of this compound in the production field has become more and more popular.

Reference:
Patent; Shanghai Aobo Pharmtech, Inc., Ltd.; Zhejiang Huahai Pharmaceutical Co., Ltd; Zhu, Wei; Fan, Qianyong; Ruan, Hongliang; (12 pag.)CN102757431; (2016); B;,
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. 486424-37-7, name is 3-Amino-6-bromopyrazine-2-carboxylic acid, A new synthetic method of this compound is introduced below., Formula: C5H4BrN3O2

HATU (47.6 g) was added to a stirred solution of 1 ,2-phenylenediamine (13.54 g), 3-amino-6-bromopyrazine-2-carboxylic acid (26.0 g) and triethylamine (24.93 ml) in DMF (250 mL). The resulting solution was stirred at ambient temperature for 12 hours before the reaction mixture was added to water (250 ml). The resulting precipitate was collected by filtration, washed with water (250 ml) and dried in vacuo. This material was dissolved in acetic acid (200 ml) and heated to 9O0C for 4 hours. The reaction mixture was concentrated in vacuo, washed with diethylether. The ether washings were evaporated and triturated in hexane. There was thus obtained 3-(lH-benzimidazol-2-yl)-5-bromopyrazin-2-amine (5.Og); Mass Spectrum: M-H+ 290; RT 2.46 min. NMR Spectrum: (DMSOd6) 7.32 (m, 2H), 7.60 (d, IH), 7.78 (d, IH), 8.31 (s, IH), 13.2 (s, IH).

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; AstraZeneca AB; AstraZeneca UK Limited; WO2009/24825; (2009); A1;,
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. 16298-03-6, name is Methyl 2-aminopyrazine-3-carboxylate, This compound has unique chemical properties. The synthetic route is as follows., category: Pyrazines

EXAMPLE 157A Methyl 3-bromopyrazine-2-carboxylate To a rapidly stirring heterogeneous mixture of 3-aminopyrazine-2-carboxylic acid methyl ester (2.00 g, 13.1 mmol) in 48percent hydrobromic acid (7.9 mL) cooled to 0¡ã C. was added bromine (2.00 mL, 6.2 g, 38.8 mmol) dropwise over 5 minutes. Then a solution of sodium nitrite (2.27 g, 32.8 mmol) in 9.5 mL of water was added dropwise over 10 minutes. The reaction mixture was stirred at 0¡ã C. for 15-30 minutes and then basified with 60 mL of saturated sodium bicarbonate solution and extracted with ethyl acetate followed by chloroform. The combined organic extracts were dried over magnesium sulfate and concentrated under reduced pressure. The residue obtained was flash chromatographed on silica gel eluding with mixtures of hexane and ethyl acetate to afford the title compound (1.265 g, 46percent). m.p. 43.5¡ã-44¡ã C. 1 H NMR (CDCl3, 300 MHz) delta 4.04 (s, 3H), 8.50 (bs, 1H), 8.60 (bs, 1H). MS (DCl/NH3) m/e 217/219 (M+H)+, 234/236 (M+H+NH3)+.

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 16298-03-6.

Reference:
Patent; Abbott Laboratories; US5250548; (1993); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Synthetic Route of 59489-71-3,Some common heterocyclic compound, 59489-71-3, name is 2-Amino-5-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.

EXAMPLE 2; 5-bromopyrazine-2-carbonitrile; i) Tetrakis (triphenyl phosphine) palladium(0) (10 mg) was added to a mixture of 5-bromopyrazin-2-amine (0.575 mmol), potassium cyanide (1.15 mmol), copper (I) iodide (0.575 mmol) and 18-crown-6 (20 mg) in dry DMF (1 mL) in a screw top reaction vessel under nitrogen atmosphere, and the mixture was heated with stirring at 200 C. for 1 h. After cooling, water (5 mL) was added and the product was extracted with chloroform (2¡Á) to give 5-aminopyrazine-2-carbonitrile after purification by chromatography (silica, hexane:ethyl acetate) (0.208 mmol, 36%).

The synthetic route of 59489-71-3 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; AstraZeneca AB; NPS PHARMACEUTICALS, INC.; US2007/37820; (2007); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem