Tag: M.W:300-400

1228780-72-0, 1-((4′-Chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazine is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

In a 500-mL three necked round bottom flask equipped with magnetic stirrer, thermometer, condenser, charged 4-bromo-2-(1H-pyrrolo[2,3-b]pyridine-5-yloxy)benzoic acid (8.67 g, 26 mmol), (4-(N,N-dimethylamino)phenyl)-di-tert-butyl-phosphine (APhos, 895 mg, 0.78 mmol, 0.13 equiv), tris(dibenzylideneacetone)-dipalladium(0) (1.54 g, 1.69 mmol, 0.065 equiv), THF (87 mL) and 1-[[2-(4-chlorophenyl)-4,4-dimethylcyclohex-1-enyl]methyl]piperazine in toluene (31.2 g, 29 mmol, 1. 12 equiv). The reaction mixture was stirred under inert atmosphere, 1.5 M lithium bis(trimethylsilyl)amide in THF (74 mL, 112 mmol, 4.3 equiv) was added, and heated to 55-56C. The reaction mixture was stirred at 55-56C for 30 min then quenched by addition of cold (2-8C) 12% aqueous NaCl (347 mL). After phase separation the organic layer was filtered and concentrated in vacuum to 1/3 volume. The residue was added to a cold (0-5C) suspension of perlite (22 g) in n-heptane (364 mL). The suspension was stirred for 1 hour at 0-5C then filtered. The wet-cake was washed with n-heptane (3 x87 mL), and dried under vacuum at 20-25C for 2 hours. The solid was suspended in THF (87 mL), filtered and the wet cake was washed with THF (4×87 mL). HPLC-analysis of the combined THF solution comprised 8.3 g of VNT-08 content (yield: 56%).

1228780-72-0, 1228780-72-0 1-((4′-Chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazine 66713599, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; ASSIA CHEMICAL INDUSTRIES LTD.; TEVA PHARMACEUTICALS USA, INC.; POTARINE JUHASZ, Zsuzsa; STRUBA, Szabolcs; NEMETHNE RACZ, Csilla; TOTH, Zoltan Gabor; SZILAGYI, Andrea; KERTI-FERENCZI, Renata; MOLNAR, Sandor Janos; PASZTOR-DEBRECZENI, Nora; HAJKO, Janos; (100 pag.)WO2017/156398; (2017); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1001180-21-7, (R)-tert-Butyl 4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Step 9: Triethylamine (4.33 ml, 31.1 mmol; degassed with nitrogen 30 minutes prior to use) and formic acid (1.36 ml, 36.1 mmol; degassed with nitrogen 30 minutes prior to use) were added to a solution of (R)-tert-butyl 4-(5-methyl-7-oxo-6,7-dihydro-5H- cyclopenta[d]pyrimidin-4-yl)piperazine-l-carboxylate (9.75 g, 29.3 mmol) in DCM (210 mL; degassed with nitrogen 30 minutes prior to use). The mixture was stirred for 5 minutes, then a Ru catalyst (0.0933 g, 0.147 mmol) was added. The reaction was stirred under positive nitrogen pressure overnight (18 hours). The reaction mixture was concentrated to dryness and dried on high vacuum. The impure material was flashed on Biotage 65M loaded 1 : 1 DCM:ethyl acetate 500 mL flushed, then 1 :4 DCM:ethyl acetate until product (2nd spot), then gradient to neat ethyl acetate, then 25:1 DCM:MeOH eluted rest of product. The fractions were combined and concentrated on a rotary evaporator. The residue was concentrated again from DCM/hexanes to give a mixture of tert-butyl 4-((5R,7R)-7-hydroxy- 5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine- 1 -carboxylate (major) and tert-butyl 4-((5R,7S)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4- yl)piperazine-l -carboxylate (minor) (9.35 g, 95.3% yield) as a beige foam. LC/MS (APCI+) m/z 335 [M+H]+. 1H NMR (CDC13) shows 88% de by integration of carbinol methine., 1001180-21-7

1001180-21-7 (R)-tert-Butyl 4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate 59580350, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; GENENTECH, INC.; HOEFLICH, Klaus; MERCHANT, Mark; WO2012/135750; (2012); 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.112984-60-8,6-Fluoro-1-methyl-4-oxo-7-(piperazin-1-yl)-1,4-dihydro-[1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid,as a common compound, the synthetic route is as follows.

Example 1 Preparation of (S)-(-)-uliflourxacin; 105 g of racemic uliflourxacin was dissolved in 1,500 mL of dimethyl sulfoxide. 27 g of D-tartaric acid was dissolved in 405 mL of dimethyl sulfoxide dropwise while stirring. After stirring at room temperature for 20 hours, the precipitate was filtrated. The collected solid was dried under vacuum to obtain 86 g solid, which was recrystallized in dimethyl sulfoxide to obtain 37 g of levoulifloxacin-D-tartrate, with C49.08%, H5.06%, N9.50%, S7.44% shown by elemental analysis (molecular formula: C16H16FN3O3S·1/2C4H6O6·H2O, calculated values: C48.86%, H4.78, N9.50%, S7.25%). Said salt was added into water to obtain a suspension, and the pH value was adjusted to 7-8 with 2% NaOH aqueous solution while stirring. After precipitation, filtration, and drying, 24.5 g of (S)-uliflourxacin was obtained, having a chemical name (S)-(-)-6-fluoro-1-methyl-4-oxo-(1-piperazinyl)-1H,4H-[1,3]thiazeto [3,2-alpha]quinoline-3-carboxylic acid. Specific rotation [alpha]20D= -133 (c=0.5, 0.1 mol/L methanesulfonic acid); 1H-NMR (DMSO-d6) delta2.11 (3H, d, j=6.2 Hz), 2.87 (4H, m), 3.19 (4H, m), 6.40 (1H, q, j=6.2 Hz), 6.89 (1H, d, j=7.4Hz), 7.79 (1H, d, j=13.9Hz), optical purity e.e. 96%.

112984-60-8, 112984-60-8 6-Fluoro-1-methyl-4-oxo-7-(piperazin-1-yl)-1,4-dihydro-[1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid 124225, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; Hainan Hualon Pharmaceutical Co., Ltd.; EP2524922; (2012); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1228780-72-0, 1-((4′-Chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazine is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

In a 500-mL three necked round bottom flask equipped with magnetic stirrer, thermometer, condenser, charged 4-bromo-2-(1H-pyrrolo[2,3-b]pyridine-5-yloxy)benzoic acid (8.67 g, 26 mmol), (4-(N,N-dimethylamino)phenyl)-di-tert-butyl-phosphine (APhos, 895 mg, 0.78 mmol, 0.13 equiv), tris(dibenzylideneacetone)-dipalladium(0) (1.54 g, 1.69 mmol, 0.065 equiv), THF (87 mL) and 1-[[2-(4-chlorophenyl)-4,4-dimethylcyclohex-1-enyl]methyl]piperazine in toluene (31.2 g, 29 mmol, 1. 12 equiv). The reaction mixture was stirred under inert atmosphere, 1.5 M lithium bis(trimethylsilyl)amide in THF (74 mL, 112 mmol, 4.3 equiv) was added, and heated to 55-56C. The reaction mixture was stirred at 55-56C for 30 min then quenched by addition of cold (2-8C) 12% aqueous NaCl (347 mL). After phase separation the organic layer was filtered and concentrated in vacuum to 1/3 volume. The residue was added to a cold (0-5C) suspension of perlite (22 g) in n-heptane (364 mL). The suspension was stirred for 1 hour at 0-5C then filtered. The wet-cake was washed with n-heptane (3 x87 mL), and dried under vacuum at 20-25C for 2 hours. The solid was suspended in THF (87 mL), filtered and the wet cake was washed with THF (4×87 mL). HPLC-analysis of the combined THF solution comprised 8.3 g of VNT-08 content (yield: 56%).

1228780-72-0, 1228780-72-0 1-((4′-Chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazine 66713599, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; ASSIA CHEMICAL INDUSTRIES LTD.; TEVA PHARMACEUTICALS USA, INC.; POTARINE JUHASZ, Zsuzsa; STRUBA, Szabolcs; NEMETHNE RACZ, Csilla; TOTH, Zoltan Gabor; SZILAGYI, Andrea; KERTI-FERENCZI, Renata; MOLNAR, Sandor Janos; PASZTOR-DEBRECZENI, Nora; HAJKO, Janos; (100 pag.)WO2017/156398; (2017); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1001180-21-7, (R)-tert-Butyl 4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Step 4: (Reaction run in a 20-mL plastic bottle): To a solution of (R)-tert-butyl 4-(5- methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-l-carboxylate (0.250 g, 0.752 mmol) in 5 mL DCM was added DAST (0.795 mL, 6.02 mmol). The reaction mixture was capped and stirred at room temperature for 45 hours, after which it poured into ice saturated NaHCO3. The mixture was extracted with 2 x 40 mL DCM, and the combined extracts were dried (Na2SO4), filtered, and concentrated in vacuo. The crude was purified on silica gel (Biotage 40S) eluting with 6:1 to 3:1 hexanes:EtOAc to give (R)-tert-butyl 4-(7,7-difluoro-5-methyl-6,7-dihydro- SH-cyclopenta^pyrimidin^-ytypiperazine-l-carboxylate (0.092 g, 34.5% yield) as a yellow oil. MS (APCI+) m/z 355 [M+H]+.

1001180-21-7, 1001180-21-7 (R)-tert-Butyl 4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate 59580350, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; ARRAY BIOPHARMA INC.; GENENTECH, INC.; MITCHELL, Ian S.; BLAKE, James F.; XU, Rui; KALLAN, Nicholas C.; XIAO, Dengming; SPENCER, Keith Lee; BENCSIK, Josef R.; LIANG, Jun; SAFINA, Brian; LI, Jun; CHABOT, Christine; WO2008/6032; (2008); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

112257-12-2, tert-Butyl 4-(2-bromoacetyl)piperazine-1-carboxylate is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Commercially available imidazole (0.33 g, 4.9 mmol) was dissolved in 2 mL of freshly distilled DMF, under N2, and cooled to 0 C. Sodium hydride (0.14 g, 5.9 mmol) was added to the reaction and stirred for 30 min before a dropwise addition of tert-butyl 4-(2-bromoacetyl)piperazine-1-carboxylate (1.50 g, 4.9 mmol) dissolved in 2 mL of DMF. The mixture was slowly warmed to room temperature and stirred overnight. Addition of 10 mL of water caused a white precipitate to form. The solid was filtered and dried under reduced pressure overnight to afford tert-butyl 4-(2-(1H-imidazol-1-yl)acetyl)piperazine-1-carboxylate 8a (0.97 g,3.3 mmol, 67%); mp: 147-149 C. 1H NMR (400 MHz, CDCl3) delta 7.53(s, 1H), 7.11 (s, 1H), 6.96 (s,1H), 4.80 (s, 2H), 3.62 (bs, 2H), 3.48 (bs,6H), 1.47 (s, 9H); 13C NMR (100 MHz, CDCl3) delta 165.0, 154.5, 138.1, 129.7, 120.2, 80.8, 48.2, 45.1, 43.5, 42.2, 28.5; HRMS (ESI TOF): [M+H]+Calc’d for C14H23N4O3 m/z 295.1770. Found, m/z 295.1751.

112257-12-2, As the paragraph descriping shows that 112257-12-2 is playing an increasingly important role.

Reference：
Article; Abuteen, Akram; Zhou, Feifei; Dietz, Christopher; Mohammad, Innus; Smith, Michael B.; Zhu, Quing; Dyes and Pigments; vol. 126; (2016); p. 251 – 260;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1228780-72-0, 1-((4′-Chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazine is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

1228780-72-0, Combined 2-((1H-pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-bromobenzonitrile (6.6 g) and 1-((4’chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[ 1,1 ‘-biphenyl]-2-yl)methyl)piperazine (7. 7 g) intetrahydrofuran (200 mL). To the reaction mixture sodium tert. Butoxide (6.0 g) and ( 4-(N,N-Dimethylamino)phenyl)di-tert-butyl phosphine (A-phos) (445 mg) were added at30C and degassed with Argon for 30 minutes under stirring at the same temperature.Tris(dibenzylideneacetone)dipalladium(O)-chloroform adduct (870 mg) was added anddegassed for 5 minutes at 30C. The reaction mixture was heated to 70C and stirred for15 hours at the same temperature. The reaction mixture was cooled and filtered on celitebed. The celite bed was washed with tetrahydrofuran (2 x 50 mL) and evaporated thesolvent in the filtrate. The crude product was dissolved in the ethyl acetate (100 mL) andwashed with water (100 mL), saturated sodium bicarbonate solution (70 mL), 10%solution of L-cysteine (100 mL) and brine solution (60 mL). The organic solution wasdried over sodium sulfate and evaporated the solvent under reduced pressure. The crudeproduct was purified by column chromatography using 100-200 mesh silica gel and 40-50% ethyl acetate-hexane as eluent to obtain the title compound as yellow solid. Yield:9.5 g; Purity by HPLC: 98.30%

The synthetic route of 1228780-72-0 has been constantly updated, and we look forward to future research findings.

Reference：
Patent; DR. REDDY?S LABORATORIES LIMITED; PEDDIREDDY, Subba Reddy; KOTTUR, Mohan Kumar; JURUPULA, Ramprasad; BAIG, Mohammed Azeezulla; CHAKKA, Ramesh; THIPPARABOINA, Rajesh; PEDDY, Vishweshwar; RAO, Pallavi; ORUGANTI, Srinivas; DAHANUKAR, Vilas Hareshwar; (88 pag.)WO2017/212431; (2017); 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.1072027-36-1,4-(4-Boc-1-piperazinyl)-5-bromo-7H-pyrrolo[2,3-d]pyrimidine,as a common compound, the synthetic route is as follows.

Description 16; 1,1 -Dimethylethyl 4-{5-bromo-7-[2-(ethyloxy)-2-oxoethyl]-7H-pyrrolo[2,3- d]pyrimidin-4-yl}-1 -piperazinecarboxylate (D16)1 ,1-Dimethylethyl 4-(5-bromo-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1- piperazinecarboxylate (D15, 552 mg, 1.444 mmol) was dissolved in N, N- dimethylformamide (14 ml_), cooled in an ice bath and treated with sodium hydride (60% by weight, 69.3 mg, 1.733 mmol) portionwise and stirred under argon for 15 minutes. The reaction mixture was allowed to warm to room temperature and stirred for 1 hour. Ethyl bromoacetate (0.160 ml_, 1.444 mmol) was added and the resulting mixture stirred for 1 hour. The solvent was removed under reduced pressure. The residue taken up in water, neutralised using saturated ammonium chloride and extracted with ethyl acetate (x 3). The ethyl acetate layers were combined, dried under magnesium sulfate and evaporated under reduced pressure. The residue was purified by column chromatography eluting with a gradient of 0-50 % ethyl acetate/iso-hexane. Product containing fractions were combined and evaporated under reduced pressure to give the title compound as a white solid. LC/MS (ES+ve): [M+H]+ at m/z 468, 470 (Ci9H26BrN5O4 requires [M+H]+ at m/z 468, 470).

1072027-36-1, As the paragraph descriping shows that 1072027-36-1 is playing an increasingly important role.

Reference：
Patent; GLAXO GROUP LIMITED; WO2009/80682; (2009); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

181955-79-3, 1,4-Di-Boc-piperazine-2-carboxylic acid is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

l54-Di(tert-butoxycarbonyl)piperazine-2-carboxylic acid (14.45 g, 43.7 mmol) was dissolved in THF (200 mL), and borane-THF complex (1.0 M solution in THF, 100 mL, 100 mmol) was added slowly. Upon complete addition, the reaction mixture was heated to 50 0C. After 2 h, the reaction mixture was allowed to cool to rt and was slowly quenched by the dropwise addition of MeOH (50 mL). After gas evolution ceased, the reaction mixture was heated to 50 0C for 1 h. Upon cooling to rt, the reaction mixture was concentrated under reduced pressure. The material was dissolved in THF (200 mL) and NaH (60% dispersion in mineral oil, 1.75 g, 43.7 mmol) was added portion wise. The reaction mixture was heated to 50 0C overnight. Upon cooling to rt, the reaction mixture was quenched with H2O (300 mL) and extracted with EtOAc (3 x 400 mL). The combined organics were dried over Na2SO4, filtered, and concentrated under reduced pressure. The material was purified by column chromatography (10 to 40% EtOAc in Hexanes gradient) to give 6.31 g (59%) of the desired product as a white solid. Rf = 0.43 in 80% EtOAc in Hexanes. 1.10 g (8%) of di-tert-butyl 2- (hydroxymethyl)piperazine-l,4-dicarboxylate was also isolated. Rf= 0.63 in 80% EtOAc in Hexanes.; Borane-THF complex (1.0 M solution in THF, 200 mL, 200 mmol) was added slowly to a solution of l,4-bis(tert-butoxycarbonyl)piperazine-2-carboxylic acid (30.3 g, 91.7 mmol) in THF (100 mL). Upon complete addition, the reaction mixture was heated to 50 0C for 2 h. Upon cooling to rt, the reaction mixture was carefully quenched by the dropwise addition of MeOH. After gas evolution ceased, the reaction mixture was concentrated under reduced pressure. The material was dissolved in EtOAc (300 mL) and washed with 1 N NaOH (2 x 200 mL) and brine (200 mL). The organics were dried over Na2SO4, filtered, and concentrated under reduced pressure. The material was twice dissolved in THF (50 mL) and concentrated under reduced pressure. The material was dissolved in THF (200 mL) and NaH (60% dispersion in mineral oil, 0.366 g, 0.916 mmol) was added portionwise. The reaction mixture was heated to reflux. After 1 h, the reaction mixture was allowed to cool to rt and was concentrated under reduced pressure. The material was dissolved in EtOAc (300 mL), washed with water (2 x 200 mL) and brine (200 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure. The resulting solid was dissolved in EtOAc (200 mL) with heating, diluted with hexanes (200 mL) and allowed to cool to rt. The white, crystalline solid was collected by filtration after 5 h, washed with hexanes (2 x), and dried under vacuum. This gave 13.29 g (60%) of the product. The filtrate was concentrated under reduced pressure, dissolved in EtOAc (50 mL) with heating, and diluted with hexanes (200 mL). This was allowed to cool to rt and sit over the weekend. The white, crystalline solid was collected by filtration, washed with hexanes (2 x), and dried under vacuum. This gave an additional 4.49 g (20%) of the product. Analytical data: Rf = 0.43 in 80% EtOAc / Hexanes; 1H NMR (400 MHz, CDC13) delta 4.41 (t, J = 8.4 Hz, IH), 4.35-3.98 (br, 2H), 3.92 (dd, J = 5.6 and 8.8 Hz, IH), 3.80-3.72 (m, 2H), 2.98 (dt, J = 3.6 and 12.4 Hz, IH), 2.86-2.70 (br, IH), 2.70-2.55, (br, IH), 1.45 (s, 9H); 13C NMR (100 MHz, CDC13) delta 156.7, 154.2, 81.1, 65.5, 52.9, 47.7 (br), 43.4 (br), 41.1, 28.7. LC-MS: RT = 6.46 min; [M+Na]+ = 264.9. Anal. Calcd for CnH18N2O4: C3 54.53; H, 7.49; N, 11.56. Found: C, 54.38; H, 7.44; N, 1 1.35.

181955-79-3, 181955-79-3 1,4-Di-Boc-piperazine-2-carboxylic acid 11255979, apiperazines compound, is more and more widely used in various fields.

Reference：
Patent; CRITICAL THERAPEUTICS, INC.; WO2007/146066; (2007); A2;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics

1228780-72-0, 1-((4′-Chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1′-biphenyl]-2-yl)methyl)piperazine is a piperazines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated

Compound J, methyl 2-(1H-pyrrolo[2,3-b]pyridin-5-yloxy)-4-(4-((2-(4-chlorophenyl)- 4,4-dimethylcyclohex-1-enyl)methyl)piperazin-1-yl)benzoate, may be prepared as follows. A mixture of Compound I (1.55 g), Compound F (2.42 g), and HK2PO4 (1.42 g) in dimethylsulfoxide (20 mL) at 135 C. was stirred for 24 hours. The reaction was cooled, diluted with ether (400 mL), and washed with 3×1M NaOH, and brine, and concentrated. The crude product was chromatographed on silica gel with 10-50% ethyl acetate/hexanes to provide the product (Compound J).

1228780-72-0, As the paragraph descriping shows that 1228780-72-0 is playing an increasingly important role.

Reference：
Patent; ACERTA PHARMA B.V.; HAMDY, Ahmed; ROTHBAUM, Wayne; IZUMI, Raquel; LANNUTTI, Brian; COVEY, Todd; ULRICH, Roger; JOHNSON, Dave; BARF, Tjeerd; KAPTEIN, Allard; (732 pag.)WO2016/24230; (2016); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics