Tag: M.W:200-300

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 1125828-26-3 as follows. Recommanded Product: 1-(2-Bromo-5-chlorophenyl)-3-methyl-1H-pyrazole

The above THF solution was transferred to a jacketed 3L 3-neck round bottom flask equipped with a mechanical stirrer, a temperature controller, and a nitrogen inlet. After diluting with THF (800 mL), the water content in the solution was checked by KF (0.053%). To the above solution was added a solution of i-PrMgCl in THF (Aldrich 2 M, 286 mL, 0.572 mol) at 0-10 C. over 1 hours. The resulting solution was stirred for 30 minutes at 10 C. (GC showed the completion of magnesium-bromine exchange reaction). Ethyl trifluoroacetate (74 mL, 0.620 mol) was then added to the Grignard solution between -20 and -10 C. over 45 minutes, slowly warmed to 0 C., and stirred for 30 minutes at the same temperature. The reaction mixture was poured into 2 N HCl (300 mL) at 0 C., and stirred for 30 minutes at room temperature. The organic layer was diluted with MTBE (500 mL), and washed with brine (250 mL) followed by water (250 mL). Solution assay of organic layer was carried out using GC (Compound 5: 67% solution yield, the corresponding regioisomer 6 was present at about 20% relative to 5). The solution was then concentrated under vacuum to 2× solution. To remove water, THF (500 mL) was added, and evaporated to 2× solution. THF addition-concentration was repeated to give a 2× solution. Heptane (500 mL) was added, concentrated to 2× solution to exchange the solvent for recrystallization. Heptane (500 mL) was again added, concentrated to 3.5× solution.The 3.5× heptane solution was then transferred to a 1L 3-neck jacketed round bottom flask equipped with a mechanical stirrer, a temperature controller, and a nitrogen inlet. The solution was heated at 60 C., and the resulting homogeneous solution was slowly (1-2 h) cooled to room temperature with stirring, further cooled to 0 C. and stirred for 30 minutes at the same temperature. The crystals were collected and washed with ice-cold heptane (200 mL), dried under vacuum at 50 C. to afford a pale yellow solid (Compound 5, 85.7 g, 99% pure by GC, 62% yield from fluoride 1). M.p.: 83 C. (DSC onset temperature) 1H NMR (400 MHz, CDCl3) delta 7.85 (1H, d, J=2.5 Hz), 7.48 (1H, d, J=1.7 Hz), 7.38 (1H, d, J=8.3 Hz), 7.31 (1H, dd, J=8.1, 1.8 Hz), 6.33 (1H, d, J=2.5 Hz), 2.30 (3H, s); 13C NMR (100 MHz, CDCl3) delta 184.2 (q, JC-F=36.6 Hz), 151.7, 138.7, 138.5, 130.7, 126.4, 125.7, 124.5, 116.8, 116.1 (q, JC-F=289.8 Hz), 109.7, 13.0; 19F NMR (376 MHz, CDCl3) delta=-76.8 (s).

According to the analysis of related databases, 1125828-26-3, the application of this compound in the production field has become more and more popular.

Reference:
Patent; Bednarz, Mark S.; Burgoon, JR., Hugh Alfred; Iimura, Shinya; Kanamarlapudi, Ramanaiah C.; Song, Qiuling; Wu, Wenxue; Yan, Jie; Zhang, Haiming; US2009/62540; (2009); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Reference of 75092-30-7, The chemical industry reduces the impact on the environment during synthesis 75092-30-7, name is 4-Iodo-1-methyl-1H-pyrazole-5-carboxylic acid, I believe this compound will play a more active role in future production and life.

A round-bottom flash was charged with 4-iodo-1-methyl-1H-pyrazole-5-carboxylic acid (297 g, 1.18 mol), DCM (2.97 L), and 1,1?-carbonyldiimidazole (CDI) (207 g, 97% by mass, 1.24 mol). The reaction mixture was stirred at room temperature for 45 min. Ammonium chloride (189 g, 3.53 mol) and triethylamine (498 mL, 3.53 mol) were added and the reaction mixture was stirred at room temperature overnight. The reaction mixture was concentrated in vacuo and the residue was suspended in H2O (3 L) and granulated at room temperature for 1 h. The solid was collected via filtration, washed with H2O, and dried in a vacuum oven to afford 4-iodo-1-methyl-1H-pyrazole-5-carboxamide as a colorless solid (222 g, 75% yield). 1H NMR (CDCl3) delta: 7.53 (s, 1H), 6.56 (br s, 1H), 6.01 (br s, 1H), 4.21 (s, 3H). UPLC (UPLC-MS Method 1): tR=0.15 min. MS (ES+): 251.1 (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, 4-Iodo-1-methyl-1H-pyrazole-5-carboxylic acid, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; Pfizer Inc.; Darout, Etzer; Dullea, Robert; Hawkins, Julie Jia Li; Londregan, Allyn T.; Loria, Paula M.; Maguire, Bruce; McClure, Kim F.; Petersen, Donna N.; Piotrowski, David W.; US2014/315928; (2014); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

1269293-48-2, name is Ethyl 5-bromo-1-methyl-1H-pyrazole-3-carboxylate, 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. Formula: C7H9BrN2O2

A mixture of ethyl 5-bromo-1-methyl-pyrazole-3-carboxylate (300 mg, 1.29 mmol) and methanamine in MeOH (10 mL, 12.87 mmol) was heated to 80 C. and stirred overnight. The reaction solution was concentrated to give the product 5-bromo-N,1-dimethyl-pyrazole-3-carboxamide (280 mg, 99% yield) as a colorless oil. LCMS (ESI) [M+H]+=218.2

The synthetic route of 1269293-48-2 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Genentech, Inc.; Chan, Bryan; Drobnick, Joy; Gazzard, Lewis; Heffron, Timothy; Liang, Jun; Malhotra, Sushant; Mendonca, Rohan; Rajapaksa, Naomi; Stivala, Craig; Tellis, John; Wang, Weiru; Wei, BinQing; Zhou, Aihe; Cartwright, Matthew W.; Lainchbury, Michael; Gancia, Emanuela; Seward, Eileen; Madin, Andrew; Favor, David; Fong, Kin Chiu; Hu, Yonghan; Good, Andrew; US2018/282282; (2018); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Electric Literature of 75092-30-7,Some common heterocyclic compound, 75092-30-7, name is 4-Iodo-1-methyl-1H-pyrazole-5-carboxylic acid, molecular formula is C5H5IN2O2, 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 65(4-lodo-2-meth -2H-pyrazol-3-yl)methanolTo a solution of 4-iodo-2-methyl-2H-pyrazole-3-carboxylic acid (1.0 g, 3.96 mmol) in tetrahydrofuran (10 mL), under an atmosphere of nitrogen, was added carbonyl diimidazole (0.78 g, 4.36 mmol, 1.1 eq.). The resulting mixture was stirred at room temperature for 1.5 hr before adding sodium borohydride (0.75 g, 19.8 mmol, 3.0 eq.) followed by a solution of methanol in tetrahydrofuran (5 mL), dropwise over a period of 10 min. The resulting mixture was stirred for 3hr before quenching with 2M aqueous hydrochloric acid (30 mL). This mixture was partition with ethyl acetate (50 mL). The organic phase was washed with 1 aqueous sodium hydrogen carbonate (20 mL), saturated brine (20 mL) and dried over sodium sulphate. The resulting mixture was filtered and the filtrate concentrated under reduced pressure to give the title compound as a brown oil (0.56 g, 60%). 1H N R (400 MHz, DMSO-d6) delta ppm 3.87 (s, 3 H) 4.48 (d, J=5.47 Hz, 2 H) 5.30 (t, 1 H) 7.42 (s, 1 H)

The synthetic route of 75092-30-7 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; PFIZER INC.; BUNNAGE, Mark, Edward; COOK, Andrew, Simon; CUI, Jingrong, Jean; DACK, Kevin, Neil; DEAL, Judith, Gail; GU, Danlin; HE, Mingying; JOHNSON, Patrick, Stephen; JOHNSON, Ted, William; LE, Phuong, Thi, Quy; PALMER, Cynthia, Louise; SHEN, Hong; WO2011/138751; (2011); A2;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

These common heterocyclic compound, 1125828-30-9, name is 1-(4-Chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethanone, 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. Formula: C12H8ClF3N2O

A 3L 3-neck jacketed round bottom flask equipped with a mechanical stirrer, a temperature controller, and a nitrogen inlet was charged sequentially with dichloro(pentamethylcyclopentadienyl)iridium (III) dimer ([Cp*IrCl2]2, STREM, CASNo.: 12354-85-7, 34 mg, 0.043 mmol), (1R,2R)-(-)-N-(4-toluenesulfonyl)-1,2-diphenylethylenediamine (STREM, CASNo.: 144222-34-4, 32 mg, 0.087 mmol), and water (400 mL, 4×) at room temperature. The resulting mixture was stirred for 3 hours at 40 C. to give a homogeneous orange solution. To this active catalyst solution was added potassium formate (145.5 g, 1.73 mol) and a solution of the ketone 1-(4-chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethanone (100 g, >99% purity by GC, 0.346 mol) in CH3CN (500 mL, 5×) at 40 C. The reaction mixture was then stirred at 40 C. for 2 hours at which time the reaction was determined to be complete by GC. After cooling to 30 C., the aqueous layer (ca. 480 mL) was removed. The organic layer (ca. 600 mL, 6×) was treated with activated carbon (Darco G-60, 20 g, 0.2×) at 45 C. for 2 hours and filtered through ¼ inch bed of Celpure P65 (USP-NF, Pharmaceutical grade, Sigma) and washed with CH3CN (200 mL, 2×). The filtrate was concentrated to 250 mL (2.5×) and transferred to a 2 L 3-neck jacketed round bottom flask equipped with a mechanical stirrer and a temperature controller. More CH3CN (50 mL, 0.5×) was added to increase the solution volume to 300 mL (3×). This solution was warmed to 60 C. and water (500 mL, 5×) was added to this solution at the same temperature. After stirring for 15 minutes at 60 C., the resulting emulsion-like milky mixture was slowly cooled to room temperature. The crystals were then filtered at room temperature, and washed with CH3CN/water (1:2, 150 mL, 1.5×). The wet cake (108 g, KF: 8.83%) was dried under vacuum at 45 C. for 4 hours to afford the desired alcohol (white solid, 95 g, 94% yield, >99% chemical purity, >99% ee, KF: 0.014%). M.p.: 120 C. (DSC onset temperature); 1H NMR (methanol-d4, 400 MHz) delta 2.19 (br. s., 3H), 5.23 (dd, 6.8 Hz, 7.2 Hz, 1H), 6.19 (d, 2.4 Hz, 1H), 7.29 (d, 2 Hz, 1H), 7.42 (dd, 2.0 Hz, 6.4 Hz, 1H), 7.59 (d, 2.4 Hz, 1H), 7.68 (d, 8.4 Hz, 1H). 13C NMR (methanol-d4) delta 13.4, 67.2, 108.3, 121.7, 124.5, 127.4, 130.1, 131.9, 134.1, 136.4, 141.6, 152.3. LC/MS: MH+=291.

The synthetic route of 1-(4-Chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethanone has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Bednarz, Mark S.; Burgoon, JR., Hugh Alfred; Iimura, Shinya; Kanamarlapudi, Ramanaiah C.; Song, Qiuling; Wu, Wenxue; Yan, Jie; Zhang, Haiming; US2009/62540; (2009); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Reference of 1239363-40-6, The chemical industry reduces the impact on the environment during synthesis 1239363-40-6, name is 1-Cyclopropyl-4-iodo-1H-pyrazole, I believe this compound will play a more active role in future production and life.

Into a dry microwave vial with stir bar was added intermediate 15.2 (200 mg, 0.625 mmol), potassium phosphate tribasic (398 mg, 1.876 mmol), (Irans)-N 1 N2-dimethylcyclohe xane-l, 2-diamine (44.5 mg, 0.313 mmol), l-cyclopropyl-4-iodo-lH-pyraz ole (293 mg, 1.251 mmol), and copper(I) iodide (35.7 mg, 0.188 mmol). The vial was sealed and purged with nitrogen. Then, DMSO (3.5 mL) was added and the solution was heated to 80C overnight. The next day, the crude material was filtered through a plug of Celite (diatomaceous earth) using EtOAc. The filtrate was concentrated and purified by reverse phase prep-HPLC (Method A) to afford intermediate 15.3, (R and S)-5-chloro-l-(l -cyclopropyl- lH-pyrazol-4-yl)-6- (l-(3-methyltetrahydrofuran-3-yl)piperidin-4-yl)-lH-indazole, TFA salt. MS (ESI) m/z calc?d for C23H28CIN5O [M+H]+ 426, found 426.

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-Cyclopropyl-4-iodo-1H-pyrazole, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; MERCK SHARP & DOHME CORP.; SIMOV, Vladimir; KAPLAN, William, P.; ACTON, John, J., III; ARDOLINO, Michael, J.; CHEN, Joanna, L.; FULLER, Peter, H.; GUNAYDIN, Hakan; LI, Derun; LIU, Ping; LOGAN, Kaitlyn Marie; METHOT, Joey; MORRIELLO, Gregori, J.; NEELAMKAVIL, Santhosh, F.; TORRES, Luis; YAN, Xin; ZHOU, Hua; (0 pag.)WO2020/92136; (2020); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Related Products of 75092-30-7, 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. 75092-30-7, name is 4-Iodo-1-methyl-1H-pyrazole-5-carboxylic acid, This compound has unique chemical properties. The synthetic route is as follows.

A suspension of Preparation 16 (50 mg, 0.0897 mmol), 4-iodo-2-methyl-2H-pyrazole-3-carboxylic acid (MFCD00461121) (23 mg, 0.0897 mmol), CS2CO3 (58 mg, 0.179 mmol) and PdCl2(dppf)2.CH2Cl2 (4 mg, 0.00448 mmoL) in 1,4-dioxane (0.8 mL) and H2O (0.2 mL) was stirred at 80 C. for 16 h. LCMS showed the reaction was complete. The reaction was dried over Na2SO4 and filtered. The filtrate was concentrated to dryness and purified by prep-HPLC (petroleum ether:EtOAc, 1:1) to give the N-BOC intermediate (10 mg, 20%) as a white solid. The reaction was repeated to obtain additional material.

The chemical industry reduces the impact on the environment during synthesis 4-Iodo-1-methyl-1H-pyrazole-5-carboxylic acid. I believe this compound will play a more active role in future production and life.

Reference:
Patent; Pfizer Inc.; Darout, Etzer; Dullea, Robert; Hawkins, Julie Jia Li; Londregan, Allyn T.; Loria, Paula M.; Maguire, Bruce; McClure, Kim F.; Petersen, Donna N.; Piotrowski, David W.; US2014/315928; (2014); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

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. 916766-83-1, name is 3-(4-(Chloromethyl)phenyl)-1-methyl-1H-pyrazole, A new synthetic method of this compound is introduced below., SDS of cas: 916766-83-1

4 -Chloro-5-methyl-6-(l-methyl-lH-pyrazol-3-yl)picolinonitrile (119 mg, 0.52 mmol, 1 eq), bis(pinacolato)diboron (259 mg, 1.02 mmol, 2 eq), potassium acetate (200 mg, 2.04 mmol, 4 eq), and Pd(dppf)Cl2 DCM (42 mg, 0.051 mmol, 0.1 eq) were charged to a vial which was sealed and evacuated under vacuum and purged with N2. l,4-dioxane (5 mL) was then added via syringe, and the resulting solution was stirred at 90 C for 6 h, after which time an additional 1 eq bis(pinacolato)diboron, 1 eq potassium acetate, and 0.025 eq Pd(dppf)Cl2 DCM were added. The resulting solution was stirred at 90 C for 16 h, after which time the reaction mixture was cooled to r.t. and filtered through a plug of Celite with EtOAc and DCM. Solvents were concentrated under reduced pressure to give the pinacol ester intermediate (v) as a brown solid which was used directly without further purification (166 mg, 100%). ES-MS [M+H]+ = 243.2 (mass of free boronic acid is observed). To a vial containing crude pinacol ester (166 mg, 0.52 mmol, 1 eq), 3-[4-(chloromethyl)phenyl]-l-methyl-pyrazole (169 mg, 0.82 mmol, 1.6 eq), cesium carbonate (502 mg, 1.53 mmol, 3 eq) and Pd(dppf)Cl2 DCM (56 mg, 0.077 mmol, 0.15 eq) were added. The vial was sealed and evacuated under vacuum and purged with N2. 5: 1 1,4- dioxane/EEO solution (4 mL total, degassed) was then added via syringe and the resulting solution was stirred at 90 C for 3 h, after which time the reaction mixture was cooled to r.t. and filtered through a plug of Celite with EtOAc and DCM. Solvents were concentrated under reduced pressure, and crude residue was purified by column chromatography (5-100% EtOAc in hexanes) to give the title compound as a slightly yellow foamy solid (126 mg, 67%). MR (400 MHz, CDCh) d 7.76 (d, J= 8.1 Hz, 2H), 7.43 (s, 1H), 7.38 (d, J= 1.8 Hz, 1H), 7.32 (s, 1H), 7.14 (d, J= 8.0, 2H), 6.75 (s, 1H), 6.53 (d, J= 1.8 Hz, 1H), 4.07 (s, 2H), 3.98 (s, 3H), 3.96 (s, 3H), 2.59 (s, 3H). ES-MS [M+H]+ = 369.2.

The synthetic route of 916766-83-1 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; VANDERBILT UNIVERSITY; LINDSLEY, Craig W.; CONN, P. Jeffrey; ENGERS, Darren W.; ENGERS, Julie L.; BENDER, Aaron M.; LONG, Madeline; (120 pag.)WO2019/241467; (2019); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

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. 75092-25-0, name is Methyl 4-iodo-1-methyl-1H-pyrazole-3-carboxylate, This compound has unique chemical properties. The synthetic route is as follows., category: pyrazoles-derivatives

To a mixture of methyl 4-iodo-1-methyl-1H-pyrazole-3-carboxylate(29; 263 mg, 0.99 mmol) and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (30; 1.01 g, 4.94 mmol) in DMF(3.4 mL) and H2O (1.0 mL) were added Cs2CO3 (644 mg, 1.98 mmol) and Pd(PPh3)4 (571 mg, 0.49 mmol), and the mixture was stirred at 80 C for 3 h. After the mixture was cooled at room temperature, the mixture was partitioned between water and EtOAc. The organic layer was washed with brine, dried over MgSO4, filtered and concentrated in vacuo. The residue was purified by silica gel column chromatography (0-100% EtOAc inCHCl3) to give 31 (87 mg, 41%) a pale yellow oil. 1H NMR (DMSOd6) d 3.77 (s, 3H), 3.95 (s, 3H), 7.49 (d, 2H, J = 5.3 Hz), 8.22 (s,1H), 8.55 (d, 2H, J = 5.3 Hz); MS (ESI) m/z 218 [M+H]+.

According to the analysis of related databases, 75092-25-0, the application of this compound in the production field has become more and more popular.

Reference:
Article; Hamaguchi, Wataru; Masuda, Naoyuki; Miyamoto, Satoshi; Kikuchi, Shigetoshi; Narazaki, Fumie; Shiina, Yasuhiro; Seo, Ryushi; Amano, Yasushi; Mihara, Takuma; Moriguchi, Hiroyuki; Hattori, Kouji; Bioorganic and Medicinal Chemistry; vol. 23; 13; (2015); p. 3351 – 3367;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

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. 1125828-30-9, name is 1-(4-Chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethanone, This compound has unique chemical properties. The synthetic route is as follows., Application In Synthesis of 1-(4-Chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethanone

Step 3:A solution of dichloro (pentamethylcyclopentadienyl)iridium (III) dimer([Cp*IrCl2]2, CAS No. 12354-84-6, 3 mg), (1R,2R)-(-)-(4-toluenesulfonyl)-1,2-diphenylethylenediamine(CAS No. 144222-34-4, 2.5 mg), and water (12 mL) at room temperature. Theresulting mixture was heated to 40 oC for 3 h to give a homogeneousorange solution. To this active catalyst solution, and at the same temperature(40 oC), were added potassium formate anda solution of 1-(4-chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethanone(5 g) in CH3CN. The reactionmixture was then stirred at 40 oC for 2 h. After cooling to 30 oC,the aqueous layer was removed. The organic layer was treated with activatedcharcoal (Darco G-60, 12g, CAS: 7440-44-0) at 45 oC for 2 h andfiltered through inch bed of Filter agent (CAS: 61790-53-2) and washed withCH3CN. The filtrate was concentrated to 150 mL. An additional amountof CH3CN (30 mL) was added to increase the solution volume to 180mL. This solution was warmed to 60 oC and water was added to thissolution at the same temperature. After stirring for 15 min at 60 oC,the resulting emulsion-like milky mixture was slowly cooled to room temperaturewith stirring. The crystals were then filtered at room temperature and washedwith CH3CN/water (1:2, 90 mL). The wet cake was dried under vacuumat 40 oC for 4 h to afford the title alcohol (44) as white solid (55g).

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 1125828-30-9.

Reference:
Article; Aiello, Robert; Barucci, Nicole; Bourassa, Patricia; Goldberg, Daniel R.; Paralkar, Vishwas; Valentine, James; Zavadoski, William; Zhang, Qing; De Lombaert, Stephane; Bioorganic and medicinal chemistry letters; vol. 26; 4; (2016); p. 1124 – 1129;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics