Tag: M.W:500-600

1235865-77-6, 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

4-(4-{[2-(4-chlorophenyl)-4,4-dimethylcyclohex-1-en-1-yl]methyl}piperazin-1-yl)-N-[(4-{[(trans-4-hydroxy-4-methylcyclohexyl)methyl]amino}-3-nitrophenyl)sulfonyl]-2-(1H-pyrrolo[2,3-b]pyridin-5-yloxy)benzamide A mixture of EXAMPLE 337J (3.0 g), EXAMPLE 337M (1.98 g), N,N-dimethylpyridin-4-amine (1.93 g) and N1-((ethylimino)methylene)-N3,N3-dimethylpropane-1,3-diamine hydrochloride (1.31 g) in dichloromethane (50 ml) was stirred overnight and concentrated. The residue was purified by reverse chromatography, eluted with 40%-70% acetonitrile in 0.1% TFA water. The desired fractions were concentrated to remove acetonitrile, neutralized with NaHCO3 and extracted with dichloromethane. The organic layer was dried over Na2SO4, concentrated and dried to provide the title compound. 1H NMR (400 MHz, dimethylsulfoxide-d6) delta 11.68 (s, 1H), 8.52-8.58 (m, 2H), 8.04 (d, 1H), 7.79 (dd, 1H), 7.53 (d, 1H), 7.47-7.52 (m, 2H), 7.30-7.37 (m, 2H), 7.07 (d, 1H), 7.01-7.06 (m, 2H), 6.68 (dd, 1H), 6.39 (dd, 1H), 6.19 (d, 1H), 4.25 (s, 1H), 3.25-3.32 (m, 4H), 3.07 (s, 4H), 2.75 (s, 2H), 2.09-2.24 (m, 6H), 1.95 (s, 2H), 1.50-1.73 (m, 5H), 1.28-1.43 (m, 4H), 1.06-1.18 (m, 5H), 0.92 (s, 6H)., 1235865-77-6

The synthetic route of 1235865-77-6 has been constantly updated, and we look forward to future research findings.

Reference：
Patent; ABBOTT LABORATORIES; US2010/305122; (2010); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1235865-77-6, 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

(1051) A mixture of Compound 338J (144 mg), Compound 338M (95 mg), N, N-dimethylpyridin-4-amine (123 mg) and N1-((ethylimino)methylene)-N3,N3-dimethylpropane-1,3-diamine hydrochloride (62.7 mg) in dichloromethane (7 ml) was stirred overnight and concentrated. The residue was purified by reverse chromatography, eluted with 40%-70% acetonitrile in 0.1% TFA water. The desired fractions were concentrated, neutralized with NaHCO3 and extracted with dichloromethane. The organic layer was dried over Na2SO4, filtered, concentrated and dried to provide the title compound. 1H NMR (400 MHz, dimethylsulfoxide-d6) delta 11.69 (s, 1 H), 11.38 (s, 1 H), 8.59 (t, 1 H), 8.55 (d, 1 H), 8.04 (d, 1 H), 7.79 (dd, 1 H), 7.54 (d, 1 H), 7.46-7.52 (m, 2 H), 7.30-7.38 (m, 2 H), 7.00-7.10 (m, 3 H), 6.68 (dd, 1 H), 6.39 (dd, 1 H), 6.19 (d, 1 H), 3.95 (s, 1 H), 3.25 (t, 4 H), 3.07 (s, 4 H), 2.75 (s, 2 H), 2.10-2.26 (m, 6 H), 1.95 (s, 2 H), 1.29-1.62 (m, 8 H), 1.16-1.30 (m, 2 H), 1.08 (s, 3 H), 0.92 (s, 6 H).

1235865-77-6, As the paragraph descriping shows that 1235865-77-6 is playing an increasingly important role.

Reference：
Patent; AbbVie Inc.; Catron, Nathaniel; Lindley, David; Miller, Jonathan M.; Schmitt, Eric A.; Tong, Ping; US10213433; (2019); B2;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1235865-77-6, 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

A mixture of 2-((lH-pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5, 5-dimethyl-3.4.5.6-tetrahydro[l,l’-biphenyl]-2-yl)methyl)piperazin-l-yl)benzoic acid (2.0 g) in acetone (20 mL) was treated with p-toluenesulfonicacid monohydrate (1.33 g) and stirred at 20-30 degree Celsius for 4-5h. The resulting slurry was filtered, washed with acetone (10 mL) and the solid was dried under vacuum at 45-50 degree Celsius for 16 h to furnish 2-((lH-pyrrolo [2,3-b] pyridin-5-yl)oxy)-4 -(4-((4′-chloro-5,5-dimethyl- 3.4.5.6-tetrahydro[l,l’-bi phenyl]-2-yl) methyl)piperazin-l-yl) benzoic acid p – toluenesulfonic acid salt. Yield: 86.92 % (2.26 g) HPLC Purity: 97.88% 1H NMR (DMSO-d6): d q.95 (s, 6H), 1.43 (t, J=2.0, 2.4 Hz, 2H), 2.03 (s, 2H), 2.21 (t, br, 2H), 2.29 (s, 6H), 2.77 (m, 2H), 3.09 (m, 2H), 3.29 (m, 2H), 3.61 (m, 2H), 3.74 (m, 2H), 6.42 (m, 2H), 6.76 (dd, J=2.0 Hz, 2H), 7.09 (m, 6H), 7.39 (d, J=8.4 Hz, 2H), 7.50 (t, 5H), 7.78 (d, J=9.2 Hz, 1H), 8.03 (d, J=2.4 Hz, 1H), 11.74 (s, 1H, NH)., 1235865-77-6

The synthetic route of 1235865-77-6 has been constantly updated, and we look forward to future research findings.

Reference：
Patent; FRESENIUS KABI ONCOLOGY LTD.; GUPTA, Chandan Kumar; DHIMAN, Navdeep; SANGHANI, Sunil; SINGH, Govind; LAHIRI, Saswata; CABRI, Walter; GUPTA, Nitin; (0 pag.)WO2020/3272; (2020); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1235865-77-6, 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

To a solution of 2-(lH-pyrrolo[2,3-b]pyridine-5-yloxy)-4-(4-((2-4-chlorophenyl)-4,4- dimethylcyclohex-l-enyl)methyl)piperazin-l-yl)benzoic acid (100 g) in MDC (1500 ml) were added 3-nitro-4-((tetrahydro-2H-pyran-4yl)methylmaino)benzenesulfonamide (71.78 g),DMAP(6.4l g) and EDCI. HC1 (61.16 g) at room temperature and stirred till completion of reaction. After completion of reaction, water was added to the reaction mixture, stirred for 30 minutes and filtered at room temperature. The filtrate was stirred for 30 mins at room temperature and layers were separated. The organic layer (MDC) was distilled atmospherically below at 55 C to obtain residue (diamide content 5%). To residue methanol (1000 inL) was added and temperature was raised to 50-70C and solvent (100 mL) was distilled. To the reaction mass, sodium Hydroxide (10.50 g) solution in methanol was added at 55-60C and stirred for 2 hrs. Reaction mixture was cooled to 40-45C, stirred for 45 mins and filtered. Wet cake was washed with methanol (200 ml). Obtained compound was added to dimethylformamide (300 mL), heated at 50-60C and stirred for 30-50 mins to get clear solution. Methanol (300 mL) was added to the solution at 50-60C and stirred for 30-50 mins. Reaction mixture was cooled to 25- 35C and stirred for 8hrs.The reaction mixture was filtered and solid was washed with mixture of DML: Methanol (1 :3) (100 mL). Wet cake was dried at 25-35C for 1 hr in VTD to obtain sodium salt of Venetoclax (Form AL2 of Venetoclax) 80-90 g. (>53% yield) (diamide content > 0.3% ).1H NMR (300 MHz, Dimethyl sulfoxide d6) 11.53 (br s, 1H), 8.42(br s, 1H), 8.34(t, 1H), 7.95(d, 1H), 7.64(t, 2H), 7.27-7.4l(m, 4H), 6.62-6.78(dd, 2.02), 6.29-6.30(br s, 2H), 3.83-3.88(d, 2H), 3.42(br s, 4H), 3.l9-3.29(m, 6H), 3.0l(br s, 4H), 2.89(s, 1H), 2.74-2.72(m, 3H), 2.20(br s, 6 H), l.95-l.23(m, 9H), 0.92(s, 6H).13C NMR:-l70.89, 156.59, 153.06, 149.85, 146.21, 145.00, 142.54, 135.25, 134.99, 134.45, 133.52, 132.57, 131.26, 130.49, 129.66, 129.61, 128.51, 127.37, 125.48, 123.54, 120.02, 116.22, 113.97, 109.76, 106.55, 100.05, 67.13, 60.27, 52.80, 49.09, 48.31, 47.93, 46.78, 36.25, 35.32, 34.34, 31.24, 30.70, 29.33, 28.37., 1235865-77-6

1235865-77-6 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid 66713100, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; ALEMBIC PHARMACEUTICALS LIMITED; TVSK, Vittal; CHUDASAMA, Dinesh; DONTHUKURTHI, Saisuryanarayana; SHAH, Tejas; PATIL, Chetan; VELISOJU, Mahendar; SIRIPRAGADA, Mahender Rao; (28 pag.)WO2019/150253; (2019); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.1235865-77-6,2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid,as a common compound, the synthetic route is as follows.

4-fluoro-3-nitrobenzenesulfonamide (235 mg, 1.06 mmol, 1.00 eq) and2 – ((1H-pyrrolo [2,3-b] pyridin-5-yl) oxy) -4- (4 – ((4′-chloro-5,5-dimethyl- , 6-tetrahydro- [1,1′-biphenyl] -2-yl) methyl) piperazin-1-yl) benzoic acid(600 mg, 1.06 mmol, 1.0 eq) (see Example 1, Step 14) was added to 6 mL of phosphorus oxychloride and reacted at 85 C for 5 h. The reaction solution was poured into 20 mL of ice water and extracted with EA (10 mL x 3). The organic phase was separated, dried over anhydrous sodium sulfate, dried over the column, PE / EA (v / v) = 2/1 and DCM / EtOH (v / v) = 10/1 as an eluent to give 830 mg of a white solid product in 100% yield.

1235865-77-6, As the paragraph descriping shows that 1235865-77-6 is playing an increasingly important role.

Reference：
Patent; Sunshine Lake Pharma Co.,Ltd.; Kou, Yuhui; Hu, Bolin; Jiang, Haigang; Ye, Jiuyong; Liu, Zhiqiang; Xie, Hongming; Zhang, Yingjun; (42 pag.)CN106565706; (2017); A;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.1235865-77-6,2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid,as a common compound, the synthetic route is as follows.

4-fluoro-3-nitrobenzenesulfonamide (235 mg, 1.06 mmol, 1.00 eq) and2 – ((1H-pyrrolo [2,3-b] pyridin-5-yl) oxy) -4- (4 – ((4′-chloro-5,5-dimethyl- , 6-tetrahydro- [1,1′-biphenyl] -2-yl) methyl) piperazin-1-yl) benzoic acid(600 mg, 1.06 mmol, 1.0 eq) (see Example 1, Step 14) was added to 6 mL of phosphorus oxychloride and reacted at 85 C for 5 h. The reaction solution was poured into 20 mL of ice water and extracted with EA (10 mL x 3). The organic phase was separated, dried over anhydrous sodium sulfate, dried over the column, PE / EA (v / v) = 2/1 and DCM / EtOH (v / v) = 10/1 as an eluent to give 830 mg of a white solid product in 100% yield.

1235865-77-6, As the paragraph descriping shows that 1235865-77-6 is playing an increasingly important role.

Reference：
Patent; Sunshine Lake Pharma Co.,Ltd.; Kou, Yuhui; Hu, Bolin; Jiang, Haigang; Ye, Jiuyong; Liu, Zhiqiang; Xie, Hongming; Zhang, Yingjun; (42 pag.)CN106565706; (2017); A;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1235865-77-6, 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

A mixture of (7:3) acetone-methanol (3 mL), 2-((lH-pyrrolo[2,3-b]pyridin-5-yl)oxy)-4- (4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro[l,l’-biphenyl]-2-yl)methyl)piperazin-l- yl)benzoic acid (0.5 g) and dicyclohexylamine (0.19 g) was stirred at 20-30 degree Celsius for 3-4h. The resulting slurry was filtered, washed with (7:3) acetone-methanol (2 mL) and the solid was dried under vacuum at 40-50 degree Celsius for 16 h to furnish 2-(( lH-pyrrolo[2, 3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3, 4,5,6- tetrahydro[l, l’-biphenyl]-2-yl)methyl)piperazin- l-yl)benzoic acid dicyclohexylamine salt. Yield: 60.6 % (0.4 g) HPLC Purity: 97.2 % 1H NMR (DMSO-d6): d 0.93 (s, 6H), 1.08 (m, 6H), 1.15 (m, 4H), 1.39 (t, J=6.0, 6.4 Hz, 2H), 1.50 (d, J=l2.4 Hz, 2H), 1.60 (d, J=l3.2 Hz, 4H), 1.77 (d, J=l0.8 Hz, 4H),2.l6 (m, br, 6H) 2.58 (m, 2H), 2.73 (s, 2H), 3.04 (s, 4H), 6.31 (d, J=2.8 Hz, 2H), 6.64 (d, J=7.6, Hz, 1H), 7.04 (d, J=8.0 Hz, 2H), 7.33 (d, J=8.0 Hz, 3H), 7.41 (s, 1H), 7.60 (d, J=8.8 Hz, 1H), 7.95 (d, J=2.0 Hz, 1H), 11.55 (s, 1H, NH)

1235865-77-6, As the paragraph descriping shows that 1235865-77-6 is playing an increasingly important role.

Reference：
Patent; FRESENIUS KABI ONCOLOGY LTD.; GUPTA, Chandan Kumar; DHIMAN, Navdeep; SANGHANI, Sunil; SINGH, Govind; LAHIRI, Saswata; CABRI, Walter; GUPTA, Nitin; (0 pag.)WO2020/3272; (2020); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.1235865-77-6,2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid,as a common compound, the synthetic route is as follows.

Formula 2(100 g) and triethylamine (35.2 g) was stirred in dichloromethane (500 mL). In another flask, formula 9(46.9 g), 4-dimethylaminopyridine (42.68 g), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide(46.96 g) in dichloromethane (1.2 L) was stirred. The solution of formua-2 was added slowly to the solution of formula 9 at ambient temperature and the reaction was stirred for 12 hours. The organic layer was washed with 10% acetic acid solution (750 mL) twice, followed by 5% aqueous NaHCO3 (750 mL) and 5% aqueous NaCI (750 mL). The dichloromethane layer was concentrated under vacuum at 40C. Dichloromethane (900 mL) was added and the r eaction mixture was heated to 38C. Methanol (100 mL) and ethyl acetate (800 mL) were added at 38 The reaction mass was cooled to 27±3C, stirred for 2 hours, and filtered. The solid was washed with a mixture of dichloromethane (150 mL) and ethyl acetate (150 mL). The solid was dried under vacuum at 60±5C for 4 hours. Dry weight: 76 g (Yie Id = 50%)., 1235865-77-6

As the paragraph descriping shows that 1235865-77-6 is playing an increasingly important role.

Reference：
Patent; MYLAN LABORATORIES LIMITED; JOSHI, Rajesh; TRIPATHI, Anil Kumar; CHAUDHARI, Chandrakant; GOTTUMUKKALA, Nagaraju; POKHARKAR, Kiran; SANGVIKAR, Yogesh; VADALI, Lakshmanarao; JAYACHANDRA, Suresh Babu; (48 pag.)WO2018/29711; (2018); A2;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.1235865-77-6,2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid,as a common compound, the synthetic route is as follows.

A mixture of intermediate 1 (2.42 g, 4.28 mmol)DMAP (1.05 g, 8.59 mmoL),EDCI (1.07 g, 5.58 mmoL) andDichloromethane (30.0 mL) was added to the reaction flask 1.A solution of 4- [4 – [[2- (4-chlorophenyl) -4,4-dimethyl-1-cyclohexen-1-yl] methyl] -1-piperazine] 1H-pyrrolo [2,3-b] pyridin-5-yloxy) benzoic acid (2.5 g, 4.4 mmoL)Triethylamine (0.87 g) andDichloromethane (12.0 mL) was added to the reaction flask 2. [The solution in the reaction flask 2 was slowly added dropwise to the reaction flask 1,After the dropwise addition was stirred overnight, the TLC monitored the reaction completely.N, N’-dimethylethylenediamine (0.94 g) was added,Oil bath to 55 ,Then add 10% acetic acid (18.5 mL) and stir overnight.Cooling, liquid separation. The organic phase was washed once with 10% acetic acid (18.5 mL).Dichloromethane (7.5 mL) was added to the organic phase.Followed by 5% aqueous sodium bicarbonate (18.5 mL) and5% sodium chloride (18.5 mL).The solvent was evaporated under reduced pressure and the residue was separated by flash column chromatography. The elution solvent was dichloromethane / methanol = 10/1,2.4 g of a white solid, yield 63%., 1235865-77-6

1235865-77-6 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid 66713100, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; Suzhou Guokuang Pharmaceutical Technology Co., Ltd.; Mei Desheng; Liu Aifeng; (50 pag.)CN106608895; (2017); A;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1235865-77-6, 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

2-(1H-pyrrolo[2,3-b]pyridin-5-yloxy)-4-(4-((2-(4-chlorophenyl)-4,4-dimethylcyclohex-1-enyl)methyl)piperazin-1-yl)benzoic acid (5) was synthesized by the method reported. [Nat Med. 2013, 19(2): 202-8] To a solution of compound 5 (100 mg, 0.175 mmol) in anhydrous dichloromethane, compound 4g (68 mg, 0.175 mmol), EDCI (167 mg, 0.875 mmol) and DMAP (25.6 mg, 0.21 mmol) were added. Afterwards, the mixture solution was stirred for 24 h at room temperature. Completion of the reaction was confirmed by TCL. The reaction mixture was washed with HCl (1 M), NaHCO3 saturated solution and brine, concentrated and purified to afford 6g (160 mg, 85% yield) as a yellow solid. 1H NMR (300 MHz, DMSO-d6) delta 11.70 (s, 1H), 8.64 – 8.49(m, 2H), 8.03 (d, J= 2.4 Hz, 1H), 7.86 – 7.74 (m, 1H), 7.56 – 7.45 (m, 3H), 7.33 (d, J = 8.2 Hz, 2H), 7.03 (d, J = 8.5 Hz, 3H), 6.67 (d, J = 8.0 Hz, 1H), 6.38 (s, 1H), 6.19 (s, 1H), 4.03 (q, J = 7.1 Hz, 2H), 3.09 (s, 4H), 2.79 (s, 2H), 2.23 (m, 8H), 1.94 (s, 2H), 1.67 – 1.48 (m, 4H), 1.42 – 1.23 (m, 10H), 1.15 (t, J = 7.1 Hz, 3H), 0.91 (s, 6H). MS (ESI) m/z: 940.71 [M+H]+, 938.77 [M-H]-., 1235865-77-6

1235865-77-6 2-((1H-Pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4′-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazin-1-yl)benzoic acid 66713100, apiperazines compound, is more and more widely used in various fields.

Reference：
Article; Zhou, Ruolan; Fang, Shaoyu; Zhang, Minmin; Zhang, Qingsen; Hu, Jian; Wang, Mingping; Wang, Chongqing; Zhu, Ju; Shen, Aijun; Chen, Xin; Zheng, Canhui; Bioorganic and Medicinal Chemistry Letters; vol. 29; 3; (2019); p. 349 – 352;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics