Day: November 12, 2020

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. 5744-51-4 name is Ethyl 1,5-dimethyl-1H-pyrazole-3-carboxylate, 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. 5744-51-4

Ethyl 5-methyl-1-hydro-pyrazolecarboxylate (30.8 g, 200 mmol) was dissolved in 200 mL of dry tetrahydrofuran solution. Sodium hydride (4.8 g, 200 mmol) was slowly added under ice-cooling and sodium hydride was added completely. After the temperature was raised to 50C, the mixture was stirred for 1 hour and cooled to room temperature. Methyl iodide (28.2 g, 200 mmol) was then dissolved in 100 mL of tetrahydrofuran and slowly added dropwise to the reaction. The addition was complete and heating to 50C was continued for 2 hours. After the reaction is complete, cool to room temperature, remove tetrahydrofuran under reduced pressure, then add 100 mL of water, extract with ethyl acetate (100 mL x 3), combine the organic layers, dry, and remove the ethyl acetate under reduced pressure to give 5-methyl-1-carbonitrile. Ethyl 2-pyrazolecarboxylate 26.6 g, 85%.Lithium aluminum hydride (3.8 g, 100 mmol) was added to a dry three-necked flask, 200 mL of dry tetrahydrofuran, and then ethyl 5-methyl-1-methyl-pyrazolecarboxylate (16.8 g, 100 mmol) was dissolved in 100 mL of dry. Tetrahydrofuran was slowly added dropwise to the three-necked flask, and stirring was continued for 4 hours after completion of the addition. After the reduction is completed, absolute ethanol is added dropwise to remove the remaining lithium tetrahydroaluminum, the tetrahydrofuran is removed under reduced pressure, 500 mL of methanol is added, the pH is adjusted to neutral, the mixture is heated to reflux for 6 hours, and the filtrate is filtrated. The filtrate is concentrated and dissolved in 100 mL of dichloromethane. And washed twice with 50 mL of saturated aqueous sodium chloride, and the organic layer was dried and concentrated to give 5-methyl-1-methyl-pyrazolemethanol 8.8 g, 70%.5-methyl-1-carbonitrileThe base-pyrazole methanol (6.3 g, 50 mmol) was dissolved in 20 mL of methylene chloride. Thionyl chloride (6 g, 50 mmol) was slowly added dropwise. After the addition was complete, stirring was continued for 2 hours. After the reaction was complete, saturated sodium bicarbonate was added slowly. The aqueous solution was adjusted to pH neutral and then extracted with 200 mL of dichloromethane. The organic layers were combined, dried and concentrated to give 3-chloromethyl-1-methyl-5-methylpyrazole (6.5 g, 90%).In a 50 mL round bottom flask was added 3-chloromethyl-1-methyl-5-methylpyrazole (1.44 g, 10 mmol) and N-(2,4,6-trimethylphenyl)imidazole (1.86 g) (10 mmol), 20 mL of acetonitrile, and the mixture was heated under reflux for 6 hours, cooled to room temperature, and the solvent was distilled off under reduced pressure. The obtained solid was dissolved in water and filtered. The filtrate was saturated with aqueous solution of ammonium hexafluorophosphate, and the solid precipitated and was dried to give 3.8. g imidazolium salt ligand (HL1PF6), yield 88%.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, Ethyl 1,5-dimethyl-1H-pyrazole-3-carboxylate, and friends who are interested can also refer to it.

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. 1453-58-3, name is 3-Methylpyrazole belongs to pyrazoles-derivatives compound, it is a common compound, a new synthetic route is introduced below. 1453-58-3

Potassium t-butoxide (3.9 g, 0.33 mmol) was dissolved in DMSO (25 mL). Tothis solution was added 3-methyl pyrazole (2.7 g, 0.33 mmol) and the reactionwas heated at 50 C for 30 min. 1-Bromo-4-chloro-2-fluorobenzene (4.6 g, 0.22mmol) was then added and the reaction was stirred at 50 C for 16 h. The reaction was cooled to RT and extractedwith water and ethyl acetate, washed with brine, and dried over Na2SO4,filtered and concentrated in vacuo. Purification by normal phase silica gelcolumn chromatography (ethyl acetate/heptane) provided 1-(2-bromo-5-chlorophenyl)-3-methyl-1H-pyrazoleand 1-(2-bromo-5-chlorophenyl)-5-methyl-1H-pyrazole as a 4:1 mixture (41 & 42) that was used in the nextstep directly (5.4 g).

The synthetic route of 1453-58-3 has been constantly updated, and we look forward to future research findings.

288-13-1, The chemical industry reduces the impact on the environment during synthesis 288-13-1, name is 1H-Pyrazole, I believe this compound will play a more active role in future production and life.

General procedure: 1-benzyl-4-chloro-3,5-dimethyl-1H-pyrazole. To a 16 mL vial containing 1-benzyl-3,5-dimethyl-1H-pyrazole (196 mg, 1.05 mmol) and a magnetic stir bar, 0.7 mL of water and 0.3 mL of ethyl acetate was added. Next, NaCl (123 mg, 2 mmol) was added and the vial was placed in a room temperature water bath to control exotherms. Finally, Oxone (322 mg, 0.52 mmol or 1.05 mmol KHSO5) was added and the vial was capped. The reaction proceeded with continuous and vigorous stirring until no starting material remained as indicated by TLC (1 h). The remaining oxidants were reduced with solid sodium bisulfite until starch iodide paper tested negative. Water (5 mL) was added and the mixture was extracted with 1:1 hexanes/diethyl ether (3 x 5 mL). The combined organic fractions were dried (MgSO4) and concentrated to yield crude product that was purified by flash chromatography (14 x 1 cm), 9:1 hexane/ethyl acetate eluent. Pure 1-benzyl-4-chloro-3,5-dimethyl-1H-pyrazole was obtained as a pale yellow oil (215 mg, 93% yield).

The chemical industry reduces the impact on the environment during synthesis 1H-Pyrazole. I believe this compound will play a more active role in future production and life.

288-13-1, Name is 1H-Pyrazole, 288-13-1, belongs to pyrazoles-derivatives 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 suspension of sodium hydride (1.10 eq.) in tetrahydrofurane (0.20 mL/rnmol) wasadded the solution of pyrazole (1.0 eq.) in tetrahydrofurane (0.12 mL/mmol) dropwise,while the temperature was kept under 20 C. After the mixture was stirred at room temperature for 30 minutes, the appropriate halide (1.20 eq.) was added and the mixture was stirred further at same temperature for 16 hours. Next, the reaction mixture was refluxed for 15 hours. After completion the resulting precipitate was filtered off; the filtratewas concentrated then the residue was poured onto a mixture of water and ethyl acetate. The phases were separated, and the aqueous layer was extracted with ethyl acetate. The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure. The crude product was purified via distillation. Using 2-bromopropanc in General Procedure 9G 1-isopropylpyrazole was obtained.

Statistics shows that 1H-Pyrazole is playing an increasingly important role. we look forward to future research findings about 288-13-1.

Adding a certain compound to certain chemical reactions, such as: 27258-33-9, name is 1-Methyl-1H-pyrazole-5-carbaldehyde, belongs to pyrazoles-derivatives 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 27258-33-9, 27258-33-9

General procedure: Method B [34]: The reaction mixture of aldehyde (4 mmol), acetone (116 mg, 2 mmol) and K2CO3 (1.1 g, 4 mmol) in the mixed solvent of toluene-ethanol-water (10 mL 4.0 mL 2.0 mL) was stirred at 70 C for 12 h. After cooling down to room temperature, the solvent was evaporated in vacuo. The resulting residue was partitioned between dichloromethane and water. The aqueous phase was further extracted with dichloromethane twice. The combined organic extracts were rinsed with brine and dried over anhydrous magnesium sulfate. The organic solvent was removed under vacuum to give a residue, which was purified by preparativeTLC (5% methanol in dichloromethane) or column chromatography(2% methanol in dichloromethane).

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, 1-Methyl-1H-pyrazole-5-carbaldehyde, other downstream synthetic routes, hurry up and to see.

17635-44-8, 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 17635-44-8 as follows.

The bromopyrazole 1c was prepared according to the published procedure [19]. Single crystals of (1c)2?HBr were grown from the reaction mixture at r. t. In a second crop crystals containing 1c, HBr, and Br2 in the ratio of 1 : 1 : 0.5 were obtained from this solution at r. t.

According to the analysis of related databases, 3,4,5-Tribromopyrazole, the application of this compound in the production field has become more and more popular.

5932-27-4, 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. 5932-27-4, name is Ethyl 1H-pyrazole-3-carboxylate belongs to pyrazoles-derivatives compound, it is a common compound, a new synthetic route is introduced below.

b. 4-Iodo-1H-pyrazole-3-carboxylic acid ethyl ester (Intermediate 74b) A suspension of Intermediate 74a (5.00 g, 35.7 mmol) in acetonitrile (90 mL) was treated with iodine (9.10 g, 35.7 mmol) then ceric ammonium nitrate (19.6 g, 35.7 mmol) and the mixture was stirred at RT overnight. Another portion of iodine (2.28 g, 9.0 mmol) was added and the mixture was stirred for a further 24 h then treated with ice-cold aqueous sodium hydrogensulphite solution (5%, 100 mL). The mixture was filtered through Celite rinsing with EtOAc and water. The phases were separated and the aqueous phase was extracted with EtOAc (2*). The combined organic layers were washed with water and brine, dried (Na2SO4), filtered and evaporated in vacuo. The resulting solid was triturated with ether/cyclohexane, filtered off, washed with cyclohexane and dried at 50 C. in vacuo to give the title compound (3.70 g, 39%). LCMS (Method 3): Rt 2.88 min, m/z 267 [MH+] (weak).

The synthetic route of 5932-27-4 has been constantly updated, and we look forward to future research findings.

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. 175137-46-9, name is 5-Cyclopropyl-1H-pyrazol-3-amine belongs to pyrazoles-derivatives compound, it is a common compound, a new synthetic route is introduced below. 175137-46-9

To a solution of (2J?)~2-[(2-chloro-5-nitro?yrimidin-4-yl)amino]-2-(4- fluoro?henyl)ethanol (Method 6; 300 mg, 0.96 mmol) in EtOH (4 ml) was added a solution of S-cyclopropyl-lH-pyrazol-S-amine (118 mg, 0.96 mmol) in EtOH (2 ml) and triethylamine (0.2 ml, 1.44 mmol). The reaction mixture was stirred at 45 0C for 18 hours. Solvent was removed and the residue was dissolved in EtOAc and was washed with water. The organic layer was concentrated. Flash chromatography on silica gel (EtOAc) gave the desired product as a yellowish solid (196 mg, 51%). NMR 0.64 (m, 2H), 0.92 (m, 2H), 1.83 (m, IH), 3.82 (m, 2H), 5.27 (m, 2H), 5.93 (m, IH), 7.12 (m, 2H), 7.39 (m, 2H), 8.95 (s, IH), 9.19 (s, IH), 10.54 (br s, IH), 12.11 (br s, IH).

The synthetic route of 175137-46-9 has been constantly updated, and we look forward to future research findings.

35277-02-2,Some common heterocyclic compound, 35277-02-2, name is 4-Fluoro-1H-pyrazole, molecular formula is C3H3FN2, 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 tert-butyl ((6-chloropyridazin-3-yl)methyl)carbamate (300 mg, 1.2 mmol), 4-fluoro-1H-pyrazole (106 mg, 1.2 mmol) and Cs2CO3 (1.2 g, 3.6 mmol) in ACN (20 ml) was stirred at 80 C for 6 h. The reaction mixture was then filtered, and the filtrate was concentrated to give tert-butyl ((6-(4-fluoro-1H-pyrazol-1-yl)pyridazin- 3-yl)methyl)carbamate (246 mg, Purity: 80%), which was used in the next step without further purification.

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 4-Fluoro-1H-pyrazole, its application will become more common.

A common compound: 5744-56-9, name is 1,3-Dimethyl-1H-pyrazole-5-carboxylic acid, belongs to pyrazoles-derivatives compound, it can change the direction of chemical reaction, and react with certain compounds to generate new functional products. A new synthetic method of this compound is introduced below. 5744-56-9

Scheme I 1,3-Dimethyl-4-nitro-pyrazole-5-carboxylic acid One-hundred twelve g concentrated sulfuric acid is added to 42 ml 90% nitric acid at 70-80 C., 39 g of 1,3-dimethylpyrazole-5-carboxylic acid is added in portions over one hour such that the temperature does not go over 90 C. After 2.5 hours the reaction mixture is cooled and poured over ice. The resulting percipitate was filtered, dried, and recrystallized in ethanol, mp 141-142 C.

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, 5744-56-9, other downstream synthetic routes, hurry up and to see.