Tag: M.W=300-400

Electric Literature of 120068-79-3, 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. 120068-79-3, name is 5-Amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-1H-pyrazole-3-carbonitrile belongs to pyrazoles-derivatives compound, it is a common compound, a new synthetic route is introduced below.

Example 1; Sulfinylation of 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-1 H- pyrazole-3-carbonitrile with triethylamine hydrochloride, sodium trifluoromethylsulfinate and thionylchloride, in 6.5 molar equivalents of tolueneWithin a 3-neck, 50 ml. round bottom flask equipped with a magnetic stirrer bar and a thermometer were placed vacuum dried sodium trifluoromethylsulfinate (4.29 g, 27.5 mmol), vacuum dried triethylamine hydrochloride (5.16 g, 37.5 mmol), and 13 ml. an- hydrous toluene (6.5 molar equivalents relative to 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-1 H-pyrazole-3-carbonitrile) under an argon atmosphere. After cooling to 00C to 5 0C with an ice bath, thionylchloride (3.57 g, 30 mmol) was added slowly while keeping the reaction temperature below 5 0C. After stirring for another 30 min, vacuum dried 5-amino-1-(2,6-dichloro-4-trifluoromethyl-phenyl)-1 H-pyrazole-3- carbonitrile (8.03 g, 25 mmol, 99 % purity) was added at 5 0C, and the reaction mixture was heated to 50 0C within 5 min by a preheated water bath. The temperature of 50 0C was kept for another 6 hours before quenching the reaction with 50 ml. of saturated NaHCO3 solution. The resulting suspension was diluted with 30 ml. of ethylacetate. After phase separa- tion the organic layer was washed once with saturated NaHCtheta3 solution and concentrated under reduced pressure until dryness. The crude product was crystallized from refluxing toluene (100 g) affording the title compound as a white crystalline powder (8.06 g, 70 % yield, 94 % purity by quantitative HPLC). 1H-NMR (Bruker DRX-500, d6- DMSO): delta [ppm]: 8.33 (s), 7.57 (s).; Example 3; Sulfinylation of 5-amino-1 -[2,6-dichloro-4-(trifluoromethyl)phenyl]-1 H- pyrazole-3-carbonitrile via addition of a mixture of sodium trifluoromethylsulfinate, triethylamine hydrochloride and thionylchloride to 5-amino-1-[2,6-dichloro-4- (trifluoromethyl)phenyl]-1 H-pyrazole-3-carbonitrileWithin a 3-neck, 50 ml. round bottom flask equipped with a magnetic stirrer bar and a thermometer were placed vacuum dried sodium trifluoromethylsulfinate (4.29 g, 27.5 mmol), vacuum dried triethylamine hydrochloride (5.16 g, 37.5 mmol), and 10 g anhydrous toluene under an argon atmosphere. After cooling to 0 – 5 0C with an ice bath thionylchloride (3.57 g, 30 mmol) was added while keeping the reaction temperature below 5 0C. After stirring for another 30 min the cooled sulfinic acid solution was added at once to a stirred suspension of vacuum dried 5-amino-1-(2,6-dichloro-4- trifluoromethyl-phenyl)-1 H-pyrazole-3-carbonitrile (8.03 g, 25 mmol, 99 % purity) in 5 g toluene with a temperature of 50 0C. The temperature of 50 0C was kept for another 5 hours before quenching the reaction with 50 ml. of saturated NaHCU3 solution. The resulting suspension was diluted with 30 ml. of ethylacetate. After phase separation the organic layer was washed once with saturated NaHCU3 solution and concentrated under reduced pressure until dryness. The crude product was crystallized from refluxing toluene (100 g) affording the title compound as a white crystalline powder (7.25 g, 63 % yield, 94 % purity by quantitative HPLC). 1H-NMR (Bruker DRX-500, d6- DMSO): delta [ppm]: 8.33 (s), 7.57 (s).; Example 11; Sulfinylation of 5-amino-1 -[2,6-dichloro-4-(trifluoromethyl)phenyl]-1 H- pyrazole-3-carbonitrile with thionylchloride, triethylamine hydrochloride and dosage of potassium trifluoromethylsulfinateWithin a 750 mL reactor with a mechanical stirrer and a thermometer were placed vac- uum dried triethylamine hydrochloride (51.1 g, 368 mmol), 147 g anhydrous toluene(6.5 molar equivalents relative to 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-1 H- pyrazole-3-carbonitrile), and thionylchloride (35.7 g, 294 mmol) under an argon atmosphere. After cooling to 00C to 5 0C with external cooling, vacuum dried potassium trifluoromethylsulfinate (50.4 g, 296 mmol) was added in three equal portions every 10 min while keeping the reaction temperature below 5 0C. After stirring for another 30 min, vacuum dried 5-amino-1-(2,6-dichloro-4-trifluoromethyl-phenyl)-1 H-pyrazole-3- carbonitrile (79.5 g, 245 mmol, 99 % purity) was added at 5 0C, and the reaction mixture was kept at 5 0C for 60 min and then heated to 35 0C within 45 min. The temperature of 35 0C was kept for another 10 hours before quenching the reaction with 200 g of sodium hydroxide solution (10 wt.%).The resulting suspension was diluted with 176 mL of ethylacetate. After phase separation the organic layer was washed once with sodium hydroxide solution (10 wt.%). After phase separation, the organic layer was analyzed by quantitative HPLC (79 % yield). The content of compound F was below 2.9 weight percent in the crude mixture (without solvent). The product was crystallized from a mixture of ethylacetate and toluene affording the title compound as a white crystalline powder (77.1 g, 75 % yield, 98 % purity by quantitative HPLC).; Example 15; Sulfinylation of 5-amino-1-[2,6…

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, 5-Amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-1H-pyrazole-3-carbonitrile, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; BASF SE; WO2008/55877; (2008); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Related Products of 17635-44-8, These common heterocyclic compound, 17635-44-8, name is 3,4,5-Tribromopyrazole, 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 solution of D183 (0.95 g, 8.3 mmol) in THF (50mL) was added 3,4,5-tribromo-1 H- pyrazole (2.8 g, 9.1 mmol), PPh3 (4.3 g, 16.6 mmol) and DEAD (3.6 g, 20.7mmol) at 0-5 C under N2. The reaction solution was stirred at rt for 16 hrs. The reaction solution was poured into water (50 mL) and extracted with EtOAc (100 ml_x2). The combined organic layer was washed with brine, dried over anhydrous Na2S04and concentrated in vacuo. The crude product was purified by gel silica column chromatography (PE:EtOAc from 50:1 to 10:1 ) to afford the title compound as yellow oilsolid (2.4g, yield 71.6 %). LC-MS 403.0 (M+H)+.

The synthetic route of 17635-44-8 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; GLAXOSMITHKLINE INTELLECTUAL PROPERTY DEVELOPMENT LIMITED; DING, Xiao; HO, Ming-Hsun; REN, Feng; YU, Haihua; ZHAN, Yang; (290 pag.)WO2019/12093; (2019); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Related Products of 718632-46-3, 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. 718632-46-3, name is 5-tert-Butyl 2-ethyl 3-amino-6,6-dimethylpyrrolo[3,4-c]pyrazole-2,5(4H,6H)-dicarboxylate, This compound has unique chemical properties. The synthetic route is as follows.

To a solution of 9.70 g (61.3 mmol) of 1-(trimethylsilyl)cyclopropanecarboxylic acid [synthesized according to the method described in J. Org. Chem., 1982 (47) 5, 893-895] in 120 ml of dehydrated dichloromethane, 6.60 ml (76.9 mmol) of oxalyl chloride and 0.25 ml (3.2 mmol) of dehydrated DMF were added in this order at 0C in a nitrogen atmosphere and then stirred for 2.5 hours with the temperature unchanged. After the completion of the reaction, the reaction solution was concentrated under reduced pressure and dried under reduced pressure to obtain a concentration residue. To a solution of 19.0 ml (109 mmol) of DIPEA and 9.94 g (30.6 mmol) of 5-tert-butyl 2-ethyl 3-amino-6,6-dimethylpyrrolo[3,4-c]pyrazole-2,5(4H,6H)-dicarboxylate [synthesized according to the method described in Journal of Medicinal Chemistry 2012, 55 (10), 4728-4739] in 170 ml of dehydrated dichloromethane, a solution of the obtained concentration residue in 30 ml of dehydrated dichloromethane was added at 0C in a nitrogen atmosphere and then stirred for 24 hours with the temperature unchanged. After the completion of the reaction, a saturated aqueous solution of sodium bicarbonate was added to the reaction solution and stirred, followed by extraction with dichloromethane once and ethyl acetate twice. All of the obtained organic layers were dried over anhydrous magnesium sulfate, then filtered, and concentrated under reduced pressure. The obtained concentration residue was subjected to silica gel column chromatography (elution solvent: n-hexane:ethyl acetate = 90:10 to 70:30 (V/V)), and a fraction containing the compound of interest was concentrated under reduced pressure. A concentration residue of a fraction containing impurities was subjected again to silica gel column chromatography (elution solvent: n-hexane:ethyl acetate = 90:10 to 75:25 (V/V)), combined with the purified form obtained above, concentrated under reduced pressure, and dried under reduced pressure to obtain 10.63 g of a concentration residue. To a solution of the obtained concentration residue in 100 ml of ethyl acetate, 60.0 ml (240 mmol) of 4 N hydrogen chloride/ethyl acetate was added at room temperature in a nitrogen atmosphere and then stirred for 5 hours with the temperature unchanged. After the completion of the reaction, the reaction solution was concentrated under reduced pressure. The obtained concentration residue was suspended in diisopropyl ether, and the suspension was stirred at room temperature. Insoluble matter was collected by filtration, and the obtained solid was washed with diisopropyl ether. The obtained solid was dissolved in water, and then, a saturated aqueous solution of sodium bicarbonate and dichloromethane were added and stirred at room temperature for 5 minutes. After separation into an aqueous layer and an organic layer, the aqueous layer was subjected to extraction with dichloromethane twice. All of the organic layers were washed with a saturated aqueous solution of sodium chloride, then dried over anhydrous magnesium sulfate, filtered, concentrated under reduced pressure, and dried under reduced pressure to obtain 8.27 g of the title compound (yield: 73% [2 steps]) as a light orange solid. Mass spectrum (DUIS, m/z): 365 [M+1]+. 1H-NMR spectrum (400 MHz, CDCl3) delta: 10.02 (s, 1H), 4.53 (q, J = 7.2 Hz, 2H), 4.16 (s, 2H), 1.50 – 1.43 (m, 9H), 1.14 – 1.08 (m, 2H), 0.84 – 0.77 (m, 2H), 0.12 (s, 9H).

The chemical industry reduces the impact on the environment during synthesis 5-tert-Butyl 2-ethyl 3-amino-6,6-dimethylpyrrolo[3,4-c]pyrazole-2,5(4H,6H)-dicarboxylate. I believe this compound will play a more active role in future production and life.

Reference:
Patent; Ube Industries, Ltd.; AGA, Yasuhiro; USHIYAMA, Shigeru; IWASE, Noriaki; KONO, Shigeyuki; SUNAMOTO, Hidetoshi; MATSUSHITA, Takashi; OGI, Sayaka; TANAKA, Masayuki; MATOYAMA, Masaaki; UMEZAKI, Satoshi; SHIRAISHI, Yusuke; ONUMA, Kazuhiro; KOJIMA, Masahiro; NISHIYAMA, Hayato; KIMURA, Tomio; (481 pag.)EP3214086; (2017); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Synthetic Route of 120068-79-3, These common heterocyclic compound, 120068-79-3, name is 5-Amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-1H-pyrazole-3-carbonitrile, 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.

General procedure: Phenylpyrazole (0.2 mmol), arylboronic acid (0.4 mmol), NIS (0.2 mmol), [Pd] (10 mol%), NaHCO3 (0.4 mmol) and C2H5OH:H2O (3:1, 10 mL), were added to a Schlenk tube. Then the tube was charged with N2 and the reaction mixture was stirred at 80 C for 18 h. After the completion of the reaction, as monitored by TLC, the mixture was cooled and filtrated. The filtrate was extracted with ethyl acetate and washed with brine. Then the combined organic extracts were dried over Na2SO4, concentrated under vacuum and the resulting residue was purified by silica gel column chromatography to afford the desired products.

Statistics shows that 5-Amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-1H-pyrazole-3-carbonitrile is playing an increasingly important role. we look forward to future research findings about 120068-79-3.

Reference:
Article; Lv, Ting; Zhang, Xiao-Hong; Han, Jiang-Sheng; Zhong, Ping; Journal of Fluorine Chemistry; vol. 137; (2012); p. 44 – 49;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Synthetic Route of 152120-54-2, These common heterocyclic compound, 152120-54-2, name is tert-Butyl (((tert-butoxycarbonyl)amino)(1H-pyrazol-1-yl)methylene)carbamate, 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 solution of (1S,2R)-1-((2R,3R,4S)-3-acetamido-4-azido-6-(methoxycarbonyl)-3,4-dihydro-2H-pyran-2-yl)propane-1,2,3-triyl triacetate (5.1 g, 11.5 mmol) in ethanol (300 mL) was hydrogenated with Lindlar’s catalyst for 8 h (1 atmospheric pressure). The reaction mixture was filtered through Celite and the filtrate was concentrated under reduced pressure. The resulting residue was dissolved in THF (50 mL). This solution was mixed with tert-butyl (((tert-butoxycarbonyl)amino)(1H-pyrazol-1-yl)methylene)carbamate (13.1 g, 42.21 mmol) and the resulting reaction mixture was stirred at room temperature for 18 h. It was then diluted with aq. NH4Cl and extracted with EtOAc. The combined organic layers were washed with brine, dried over Na2SO4, and concentrated under reduced pressure. Purification by silica gel chromatography (gradient elution, 1:1 EtOAc/pentane to 100% EtOAc) to afford 4.0 g of (1S,2R)-1-((2R,3R,4S)-3-acetamido-4-(2,3-bis(tert-butoxycarbonyl)guanidino)-6-(methoxycarbonyl)-3,4-dihydro-2H-pyran-2-yl)propane-1,2,3-triyl triacetate (50%). (1S,2R)-1-((2R,3R,4S)-3-Acetamido-4-(2,3-bis(tert-butoxycarbonyl)guanidino)-6-(methoxycarbonyl)-3,4-dihydro-2H-pyran-2-yl)propane-1,2,3-triyl triacetate (4.0 g, 5.94 mmol) was dissolved in methanol (20 mL) and treated with 1N NaOH (6 mL) with cooling in an ice-bath. The reaction was stirred for 30 min and neutralized with 1N HCl. Then the reaction was concentrated under reduced pressure and the residue was re-dissolved in methanol and filtered. The filtrate was concentrated under reduced pressure to afford 3.0 g of (2R,3R,4S)-3-acetamido-4-(2,3-bis(tert-butoxycarbonyl)guanidino)-2-((1S,2R)-1,2,3-triacetoxypropyl)-3,4-dihydro-2H-pyran-6-carboxylic acid (95%).

The synthetic route of 152120-54-2 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Catabasis Pharmaceuticals, Inc.; Milne, Jill C.; Jirousek, Michael R.; Vu, Chi B.; Wensley, Allison; Ting, Amal; (180 pag.)US2016/129122; (2016); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Related Products of 152120-54-2, These common heterocyclic compound, 152120-54-2, name is tert-Butyl (((tert-butoxycarbonyl)amino)(1H-pyrazol-1-yl)methylene)carbamate, 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.

N,NDi-Boc-1H-pyrazole-1-carboxamidine (500.0 mg, 1.61 mmol) was dissolved in THE dry (6.2 mL). Then Triphenylphosphine (631.4 mg, 2.41 mmol) andHydroxymethyl-cyclopropane (150.5 mg, 2.09 mmol) were added. The reaction mixture was cooled at 0 C and Diisoporpyl azodicarboxylate (0.47 mL, 2.41 mmol) was added dropwise. The temperature was increased to 70 C and the reaction mixture was stirred at reflux 1 2h. The reaction mixture was concentrated and then diluted with DCM and H20. The aqueous phase was extracted for three times with DCM; the organicphases were collected, washed with brine twice and dried over Na2504. Solvent was removed in vacuum. The crude product was purified with chromatography column in silica gel (eluent: Petroleum Ether/AcOEt 9:1) to afford compound 24 as a yellow oil (yield 82%). 1H NMR (CDCI3) O (ppm): 0.45 (d, 2H, J = 4.8 Hz); 0.49 (d, 2H, J = 5.6Hz); 1.27 (s, 9H); 1.49 (s, 9H); 1.54 (s, 1H); 3.60 (d, 2H, J = 6.8 Hz); 6.41 (t, 1H, J =2.2 Hz); 7.69 (d, 1 H, J = 1 .2 Hz); 7.95 (s, 1 H).LCMS m/z (ES+) = 387.1 [M + Na]

Statistics shows that tert-Butyl (((tert-butoxycarbonyl)amino)(1H-pyrazol-1-yl)methylene)carbamate is playing an increasingly important role. we look forward to future research findings about 152120-54-2.

Reference:
Patent; LEAD DISCOVERY SIENA S.R.L.; BOTTA, Maurizio; MACCARI, Giorgio; SANFILIPPO, Stefania; DE LUCA, Filomena; DOCQUIER, Jean-Denis; DEODATO, Davide; (56 pag.)WO2016/55644; (2016); 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. 152120-54-2, name is tert-Butyl (((tert-butoxycarbonyl)amino)(1H-pyrazol-1-yl)methylene)carbamate, This compound has unique chemical properties. The synthetic route is as follows., Computed Properties of C14H22N4O4

4-(Dimethylamino)pyridine (660 mg, 5.41 mmol) was added to a solution of tert- butyl(((tert-butoxycarbonyl)imino)(lH-pyrazol-l-yl)methyl)carbamate (11.37 g, 54.1 mmol, 1.0 equiv.) in dichloromethane (60 mL). Di-tert-butyldicarbonate (23.61 g, 108.2 mmol, 2.0 equiv.) in THF (40.0 mL) was slowly added over the course of 8 h using a syringe pump. The solution was stirred overnight at room temperature, before the solvents were removed in vacuo. The resulting colorless solid was stirred in dilute acetic acid solution (0.52 g, 8.66 mmol, acetic acid in 60 mL water). The precipitated tert-butyl tert-butoxycarbonyl(((tert-butoxycarbonyl)imino)( 1 H-pyrazol- 1 -yl)methyl)carbamate was collected, washed with water, hexane, and dried in vacuo to yield a colorless solide (20.21 g, 91% yield). FontWeight=”Bold” FontSize=”10″ H NMR (CDCb, 400 MHz): delta 8.20 (d, J= 2.4 Hz, 1H), 7.69 (d, J= 0.8 Hz, 1H), 6.45 (dd, J= 2.8, 1.6 Hz, 1H), 1.54 (s, 9H), 1.39 (s, 18H).

According to the analysis of related databases, 152120-54-2, the application of this compound in the production field has become more and more popular.

Reference:
Patent; NUTECH VENTURES; DIMAGNO, Stephen; HU, Bao; WO2015/147950; (2015); A2;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Electric Literature of 17635-44-8, 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. 17635-44-8, name is 3,4,5-Tribromopyrazole belongs to pyrazoles-derivatives compound, it is a common compound, a new synthetic route is introduced below.

EXAMPLE 34 Preparation of Ethyl 3,4,5-Tribromo-alpha-butylpyrazole-1-acetate A quantity (30.4 g., 0.1 mole) of 3,4,5-tribromopyrazole was dissolved in 500 ml. acetone and 27.6 g. (0.2 mole) solid anhydrous potassium carbonate was added. The mixture was heated at the reflux temperature with stirring for 10 minutes and after cooling 23.0 g. (0.11 mole) ethyl 2-bromohexanoate was added. This reaction mixture was heated at the reflux temperature for 11/2 hrs., cooled, and then filtered. The solids on the filter were washed with acetone and the combined acetone filtrate and acetone washes were evaporated to dryness under reduced pressure. Distillation of the residue yielded ethyl 3,4,5-tribromo-alpha-butylpyrazole-1-acetate, 41.0 g. (92% yield), having a boiling point at 138 to 140 C. at 0.15 mm. mercury pressure.

The synthetic route of 3,4,5-Tribromopyrazole has been constantly updated, and we look forward to future research findings.

Reference:
Patent; The Upjohn Company; US4084955; (1978); A;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Some common heterocyclic compound, 162758-35-2, name is 5-(4-Chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxylic acid, molecular formula is C17H11Cl3N2O2, 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. HPLC of Formula: C17H11Cl3N2O2

3.8 ml dichlorosulfoxide was added to a suspension of 6.7g of the intermediate (4) in 70 ml toluene, the mixture was refluxed for 3 hours, evaporated in vacuum to dryness. The residue was dissolved in 70 ml toluene, and evaporated in vacuum to dryness, such evaporation was repeated for three times to give 6.2 g of yellow solid intermediate (5).

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 162758-35-2, its application will become more common.

Reference:
Patent; Beijing Molecule Science and Technology Co., Ltd.; EP1975168; (2008); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

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. 17635-44-8, name is 3,4,5-Tribromopyrazole belongs to pyrazoles-derivatives compound, it is a common compound, a new synthetic route is introduced below. Product Details of 17635-44-8

General procedure: 3,4,5-Tribromopyrazole (9a; 762 mg, 2.5 mmol) or 3,5-dibromo-4-nitropyrazole(9b; 677 mg, 2.5 mmol), o-quinone methide precursor 2(2.5 mmol) and K2CO3 (only for 9a, 1.035 g, 7.5 mmol) were refluxedfor 4 h in DMF (10 mL). Product was isolated analogously to compound4a.

The synthetic route of 17635-44-8 has been constantly updated, and we look forward to future research findings.

Reference:
Article; Osipov, Dmitry V.; Osyanin, Vitaly A.; Voskressensky, Leonid G.; Klimochkin, Yuri N.; Synthesis; vol. 49; 10; (2017); p. 2286 – 2296;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics