5625-67-2

Basic information

• Product Name: Piperazin-2-one
• Synonyms: TIMTEC-BB SBB000034;PIPERAZINONE;PIPERAZIN-2-ONE;PIPERAZINE-2-ONE;AKOS BBS-00007028;AKOS BBB/413;2-PIPERAZINONE;2-OXOPIPERZAINE
• CAS NO: 5625-67-2
• Molecular Formula: C₄H₈N₂O
• Molecular Weight: 100.12
• Product Categories: pharmacetical;Piperaizine;Ketone;Building Blocks;Heterocyclic Building Blocks;Piperazines;Non-Chiral heterocyclic compounds;Heterocycles;Miscellaneous Reagents;Building Blocks;C4 to C8;Chemical Synthesis;Heterocyclic Building Blocks
• Mol File: 5625-67-2.mol
• Article Data: 35

Chemical Properties

• Melting Point: 136-140 °C(lit.)
• Boiling Point: 164°C/5mmHg(lit.)
• Flash Point: 166.3 °C
• Appearance: White to tan/Crystalline Powder
• Density: 1.053 g/cm³
• Vapor Pressure: 0.000738mmHg at 25°C
• Storage Temp.: Keep in dark place,Inert atmosphere,Room temperature
• Solubility: Chloroform
• PKA: 15.47±0.20(Predicted)
• Sensitive: Hygroscopic
• Stability: Stable, but may be light and moisture sensitive. Incompatible with oxidizing agents.
• CAS DataBase Reference: Piperazin-2-one(CAS DataBase Reference)
• NIST Chemistry Reference: Piperazin-2-one(5625-67-2)
• EPA Substance Registry System: Piperazin-2-one(5625-67-2)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38-43
• Safety Statements: 26-36/37
• RIDADR: 1759
• WGK Germany: 3
• HazardClass: 8
• PackingGroup: III
• Hazardous Substances Data: 5625-67-2(Hazardous Substances Data)

Usage

Chemical Properties

solid

Uses

2-Piperazinone (cas# 5625-67-2) is a compound useful in organic synthesis.

InChI:InChI=1/C4H8N2O/c7-4-3-5-1-2-6-4/h5H,1-3H2,(H,6,7)/p+1

Synthetic route

diazoacetic acid ethyl ester (623-73-4) + ethylenediamine (107-15-3) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With meso-tetraphenylporphyrin iron(III) chloride In dichloromethane at 22℃; for 0.166667h; Inert atmosphere;	86%
With [2-(4-hydroxymethyl)phenyl-4,4-(dimethyloxazole)Ru(CH3CN)4]PF6 In diethyl ether; water at 20℃;	80%

chloroacetic acid ethyl ester (105-39-5) + ethylenediamine (107-15-3) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
Stage #1: chloroacetic acid ethyl ester; ethylenediamine In methanol at 0 - 5℃; for 4h; Stage #2: With sodium methylate In methanol at 20 - 25℃; Solvent; Reagent/catalyst;	85.4%
Stage #1: chloroacetic acid ethyl ester; ethylenediamine In ethanol at 20℃; for 5.5h; Stage #2: With sodium ethanolate In ethanol Stage #3: With N,N-dimethyl-formamide In ethanol at 20 - 70℃; for 24h;	82%
With potassium hydroxide In ethanol Heating;	50%
Stage #1: chloroacetic acid ethyl ester; ethylenediamine In ethanol at 20℃; for 2h; Stage #2: With sodium ethanolate In ethanol at 20℃; for 14h; Stage #3: at 200℃; for 0.0833333h;	34.5%
With ethanol

chloroacetic acid ethyl ester (105-39-5) + diethylamine (109-89-7) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
Stage #1: chloroacetic acid ethyl ester; diethylamine With sodium ethanolate In ethanol at 20℃; for 5.5h; Stage #2: In DMF (N,N-dimethyl-formamide) at 20 - 70℃; for 24h;	82%

ethyl bromoacetate (105-36-2) + ethylenediamine (107-15-3) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
Stage #1: ethyl bromoacetate; ethylenediamine In ethanol at 20℃; for 2h; Stage #2: With sodium ethanolate at 20℃;	79.84%
Stage #1: ethyl bromoacetate; ethylenediamine In ethanol at 0 - 23℃; Stage #2: With sodium ethanolate In ethanol at 80℃; for 16h; Inert atmosphere;	64%

2-[(bromoacetyl)(2-phenylpropyl)amino]ethyl carbamic acid tert-butyl ester + dichloromethane (75-09-2) + potassium carbonate (584-08-7) → 2-Ketopiperazine (5625-67-2) + 1-(2-phenylpropyl)piperazin-2-one

Conditions	Yield
With trifluoroacetic acid In ethanol	A n/a B 75%

bromoethyl acetate (927-68-4) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With ammonium hydroxide; sodium ethanolate; ethylenediamine In methanol; ethanol; dichloromethane; N,N-dimethyl-formamide	45%
With ammonium hydroxide; sodium ethanolate; ethylenediamine In methanol; ethanol; dichloromethane; N,N-dimethyl-formamide	45%
With ammonium hydroxide; sodium ethanolate; ethylenediamine In methanol; ethanol; dichloromethane; N,N-dimethyl-formamide	45%

CH2Cl2:MeOH + bromoethyl acetate (927-68-4) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With ammonium hydroxide; sodium ethanolate; ethylenediamine In ethanol; N,N-dimethyl-formamide	45%
With ammonium hydroxide; sodium ethanolate; ethylenediamine In ethanol; N,N-dimethyl-formamide	45%
With ammonium hydroxide; sodium ethanolate; ethylenediamine In ethanol; N,N-dimethyl-formamide	45%

chloroacetic acid ethyl ester (105-39-5) → 2-Ketopiperazine (5625-67-2) + sodium chloride

Conditions	Yield
With sodium ethanolate; ethylenediamine In ethanol	A 34.5% B n/a

ethylenediamine (107-15-3) + Chloroacetamide (79-07-2) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With potassium carbonate at 125℃;	30%

ethanol (64-17-5) + chloroacetic acid ethyl ester (105-39-5) + ethylenediamine (107-15-3) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
at 25℃;

formaldehyd (50-00-0) + ethylenediamine (107-15-3) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With piperidine; hydrogen cyanide

ethylenediamine (107-15-3) + glycolonitrile (107-16-4) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With water

N-(2-Aminoethyl)glycinethylester (24123-13-5) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
In N,N-dimethyl-formamide at 60 - 70℃; Cyclization;
With sodium ethanolate In ethanol; toluene at 20℃; for 5h; Heating / reflux;

chloroacetic acid ethyl ester (105-39-5) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With sodium ethanolate; ethylenediamine In ethanol; N,N-dimethyl-formamide
With NaOEt In ethanol; ethylenediamine; toluene
With sodium methylate In methanol; ethanol; chloroform; ethylenediamine

diethylamine (109-89-7) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With acetyl chloride In methanol; 1,1-dichloroethane

tert-butoxide + 4-(t-butyloxycarbonyl)piperazin-2-one (76003-29-7) → 2-Ketopiperazine (5625-67-2) + 1-tert-butoxycarbonyl-4-(2-fluoroethyl)-3-oxopiperazine (194351-12-7)

Conditions	Yield
In N,N-dimethyl-formamide; isopropyl alcohol

C4H9ClN2O (1247428-43-8) → 2-Ketopiperazine (5625-67-2)

Conditions	Yield
With sodium methylate In methanol at 25 - 30℃; for 0.0833333h;

2-Ketopiperazine (5625-67-2) + di-tert-butyl dicarbonate (24424-99-5) → 4-(t-butyloxycarbonyl)piperazin-2-one (76003-29-7)

Conditions	Yield
In dichloromethane for 3h;	100%
In dichloromethane at 20℃; for 5h;	100%
In dichloromethane at 20℃; Cooling with ice;	100%

2-Ketopiperazine (5625-67-2) + trityl chloride (76-83-5) → 4-tritylpiperazin-2-one (666853-55-0)

Conditions	Yield
With triethylamine In tetrahydrofuran at -10 - 20℃;	100%

2-Ketopiperazine (5625-67-2) + 4-nitrobenzyl chloroformate (4457-32-3) → 4-p-nitrobenzyloxycarbonyl-2-ketopiperazine (623564-23-8)

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In 1,4-dioxane; dichloromethane at 0℃; for 0.5h;	100%
With N-ethyl-N,N-diisopropylamine In 1,4-dioxane; dichloromethane at 0℃; for 0.5h;	100%
With N-ethyl-N,N-diisopropylamine In 1,4-dioxane; dichloromethane at 0℃; for 0.5h;	100%
With N-ethyl-N,N-diisopropylamine In 1,4-dioxane; dichloromethane; water

2-Ketopiperazine (5625-67-2) + tert-butyl 4-{[4-amino-6-formyl-5-(7-methoxy-5-methyl-1-benzothiophen-2-yl)pyrrolo[2,1-f]-[1,2,4]triazin-7-yl]methyl}piperazine-1-carboxylate (1443531-81-4) → tert-butyl 4-( {4-amino-5-(7-methoxy-5-methyl-1-benzothiophen-2-yl)-6-[(3-oxopiperazin-1-yl)methyl]pyrrolo[2,1-f][1,2,4]triazin-7-yl}methyl)piperazine-1-carboxylate

Conditions	Yield
With sodium tris(acetoxy)borohydride; acetic acid In tetrahydrofuran at 20℃; for 2h;	100%
With sodium tris(acetoxy)borohydride; acetic acid In tetrahydrofuran at 20℃; for 2h; Enzymatic reaction;	100%

2-Ketopiperazine (5625-67-2) + N-((1S,2R)-2-amino-1,2-bis(4-chlorophenyl)ethyl)-2-isopropoxy-4-methoxybenzamide (1353891-92-5) + 1,1'-carbonyldiimidazole (530-62-1) → N-((1R,2S)-1,2-bis(4-chlorophenyl)-2-(2-isopropoxy-4-methoxybenzamido)ethyl)-3-oxopiperazine-1-carboxamide (1353891-93-6)

Conditions	Yield
Stage #1: N-((1S,2R)-2-amino-1,2-bis(4-chlorophenyl)ethyl)-2-isopropoxy-4-methoxybenzamide; 1,1'-carbonyldiimidazole In dichloromethane at 20℃; for 1.5h; Stage #2: 2-Ketopiperazine In dichloromethane at 20℃; for 18h;	99%
In dichloromethane at 20℃; for 2h;	66%
In dichloromethane at 20℃;

2-Ketopiperazine (5625-67-2) → piperazine

Conditions	Yield
With methanesulfonic acid; ruthenium(1,1,1-tris(di(3,5-dimethylphenyl)phosphinomethyl)ethane)(η4-trimethylenemethane); hydrogen In tetrahydrofuran at 160℃; under 75007.5 Torr; for 16h; Autoclave; Schlenk technique;	99%

2-Ketopiperazine (5625-67-2) + benzyl chloroformate (501-53-1) → 4-benzyloxycarbonylpiperazin-2-one (78818-15-2)

Conditions	Yield
With sodium carbonate In water; ethyl acetate for 16h; Ambient temperature;	98%
With potassium carbonate In water; ethyl acetate at 20℃; for 16h;	93%
With sodium carbonate In water; ethyl acetate at 0 - 30℃; for 16h;	84.93%

piperidine (110-89-4) + 2-Ketopiperazine (5625-67-2) + 9-fluorenylmethoxycarbonyl isothiocyanate (199915-38-3) → 3-oxopiperazine-1-carbothionic acid amide (909292-42-8)

Conditions	Yield
Stage #1: piperidine; 2-Ketopiperazine; 9-fluorenylmethoxycarbonyl isothiocyanate In chloroform at 20℃; for 2h; Stage #2: With piperidine In N,N-dimethyl-formamide at 20℃; for 6h;	98%

2-Ketopiperazine (5625-67-2) + N-((1S,2R)-2-amino-2-(4-chlorophenyl)-1-(3-methoxyphenyl)ethyl)-2-isopropoxy-4-methoxybenzamide + 1,1'-carbonyldiimidazole (530-62-1) → N-((1R,2S)-1-(4-chlorophenyl)-2-(2-isopropoxy-4-methoxybenzamido)-2-(3-methoxyphenyl)ethyl)-3-oxopiperazine-1-carboxamide

Conditions	Yield
Stage #1: N-((1S,2R)-2-amino-2-(4-chlorophenyl)-1-(3-methoxyphenyl)ethyl)-2-isopropoxy-4-methoxybenzamide; 1,1'-carbonyldiimidazole In dichloromethane at 20℃; for 1h; Inert atmosphere; Stage #2: 2-Ketopiperazine In dichloromethane at 20℃; for 15h; Inert atmosphere;	98%

2-Ketopiperazine (5625-67-2) + 2-chloropyridine-5-sulfonyl chloride (6684-39-5) → 4-((6-chloro-3-pyridinyl)sulfonyl)-2-piperazinone (1003767-51-8)

Conditions	Yield
With triethylamine In dichloromethane at 0℃; for 0.5h; Inert atmosphere;	97%
With triethylamine In dichloromethane at 0 - 20℃; for 0.5h;
Stage #1: 2-Ketopiperazine; 2-chloropyridine-5-sulfonyl chloride With triethylamine In dichloromethane at 20℃; for 0.5h; Stage #2: With sodium hydrogencarbonate In water at 20℃; for 24h;	1.12 g

2-Ketopiperazine (5625-67-2) + methyl 2-chlorosulfonyl-6-nitrobenzoate (104898-55-7) → methyl 6-Nitro-2-[3-oxo-1-piperazinylsulfonyl]benzoate

Conditions	Yield
With triethylamine In chloroform	96.8%
With triethylamine In chloroform	96.8%

2-Ketopiperazine (5625-67-2) + 2,6-dichloro-4-cyclopropylpyridine-3,5-dicarbonitrile → 2-chloro-4-cyclopropyl-6-(3-oxopiperazin-1-yl)pyridine-3,5-dicarbonitrile

Conditions	Yield
With triethylamine In N,N-dimethyl-formamide at 20℃; for 0.0833333h;	96%

2-Ketopiperazine (5625-67-2) → C5H11N3

Conditions	Yield
With hydrazine hydrate In propan-1-ol Solvent; Reflux;	95.9%

Triallylborane (688-61-9, 53588-88-8, 90721-85-0, 151452-33-4, 151452-35-6) + 2-Ketopiperazine (5625-67-2) → 2,2-diallylpiperazine (282089-93-4)

Conditions	Yield
In tetrahydrofuran for 2h; reductive diallylation; Heating;	95%

2-Ketopiperazine (5625-67-2) + allyl bromide (106-95-6) → 2,2-diallylpiperazine (282089-93-4)

Conditions	Yield
Stage #1: allyl bromide With samarium In tetrahydrofuran at 20℃; for 1h; Stage #2: 2-Ketopiperazine In tetrahydrofuran at 20℃; for 0.0666667h;	95%

2-Ketopiperazine (5625-67-2) + C17H13ClF2N2O2 (868552-03-8) → methyl 1-(4-fluorobenzyl)-3-((3-oxopiperazin-1-yl)methyl)-1H-pyrrolo[2,3-c]pyridine-5-carboxylate (868551-80-8)

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In DMF (N,N-dimethyl-formamide) at 50℃; for 4h;	95%

2-Ketopiperazine (5625-67-2) + Chloroacetic anhydride (541-88-8) → chloroacetyl-piperazinone

Conditions	Yield
In 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran; ethyl acetate	95%

2-Ketopiperazine (5625-67-2) + methyl 3-[(dimethylamino)methyl]-1-(4-fluorobenzyl)-1H-pyrrolo[2,3-c]pyridine-5-carboxylate (868552-11-8) → methyl 1-(4-fluorobenzyl)-3-((3-oxopiperazin-1-yl)methyl)-1H-pyrrolo[2,3-c]pyridine-5-carboxylate (868551-80-8)

Conditions	Yield
Stage #1: methyl 3-[(dimethylamino)methyl]-1-(4-fluorobenzyl)-1H-pyrrolo[2,3-c]pyridine-5-carboxylate With chloroformic acid ethyl ester In dichloromethane at 20℃; Inert atmosphere; Stage #2: 2-Ketopiperazine With N-ethyl-N,N-diisopropylamine In dichloromethane; N,N-dimethyl-formamide at 20℃; Inert atmosphere;	95%

2-Ketopiperazine (5625-67-2) + N-((1S,2R)-2-amino-1,2-bis(4-chlorophenyl)ethyl)-2-isopropoxy-4-methoxybenzamide (1353891-92-5) → N-((1R,2S)-1,2-bis(4-chlorophenyl)-2-(2-isopropoxy-4-methoxybenzamido)ethyl)-3-oxopiperazine-1-carboxamide (1353891-93-6)

Conditions	Yield
Stage #1: N-((1S,2R)-2-amino-1,2-bis(4-chlorophenyl)ethyl)-2-isopropoxy-4-methoxybenzamide With 1,1'-carbonyldiimidazole In dichloromethane at 20℃; for 1.5h; Stage #2: 2-Ketopiperazine In dichloromethane for 15h; Product distribution / selectivity;	95%

2-Ketopiperazine (5625-67-2) + 5-(5-Chlorosulphonyl-2-ethoxyphenyl)-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (139756-22-2) → 5-(2-ethoxy-5-((3-oxopiperazin-1-yl)sulfonyl)phenyl)-1-methyl-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one

Conditions	Yield
Stage #1: 2-Ketopiperazine With triethylamine In chloroform at 10℃; for 0.166667h; Stage #2: 5-(5-Chlorosulphonyl-2-ethoxyphenyl)-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one In chloroform at 25℃; for 6h;	95%
With N-ethyl-N,N-diisopropylamine In dichloromethane at 15 - 25℃;	70%

2-Ketopiperazine (5625-67-2) + N-(9H-fluoren-2-ylmethoxycarbonyloxy)succinimide (82911-69-1) → (9H-fluoren-9-yl)methyl 3-oxopiperazine-1-carboxylate (1119449-40-9)

Conditions	Yield
With potassium carbonate In water; ethyl acetate at 20℃;	94%

2-Ketopiperazine (5625-67-2) + 7-(2-Chloro-6-propyl-thieno[2,3-d]pyrimidin-4-yl)-3-trifluoromethyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (1215167-26-2) → 4-[6-propyl-4-(3-trifluoromethyl-5,6-dihydro-8H-[1,2,4]triazolo[4,3-a]pyrazin-7-yl)-thieno[2,3-d]pyrimidin-2-yl]-piperazin-2-one (1215167-27-3)

Conditions	Yield
In butan-1-ol at 150℃; for 2h; Microwave irradiation;	94%

2-Ketopiperazine (5625-67-2) + 2-chloro-4-fluorobenzonitrile (60702-69-4) → 2-chloro-4-(3-oxopiperazin-1-yl)benzonitrile (1372928-18-1)

Conditions	Yield
With triethylamine In water; N,N-dimethyl-formamide at 80℃; for 24h;	94%

2-Ketopiperazine (5625-67-2) + p-toluenesulfonyl chloride (98-59-9) → C18H20N2O5S2

Conditions	Yield
With sodium t-butanolate In tetrahydrofuran at 80℃; for 24h;	94%

2-Ketopiperazine (5625-67-2) + 1-bromomethyl-4-bromobenzene (589-15-1) → 4-(4-bromobenzyl)piperazin-2-on (923674-86-6)

Conditions	Yield
With triethylamine In tetrahydrofuran at 20℃; for 16h;	93%

2-Ketopiperazine (5625-67-2) + C16H12N2O2 → C14H14N4O2

Conditions	Yield
With 1,8-diazabicyclo[5.4.0]undec-7-ene In tetrahydrofuran at 20℃; for 16h;	93%

2-Ketopiperazine (5625-67-2) + 7-bromo-5-cyclopropyl-6-methyl-oxazolo[4,5-c]quinolin-4-one → 4-{7-bromo-5-cyclopropyl-6-methyl-4-oxo-oxazolo[4,5-c]quinolin-2-yl}piperazin-2-one

Conditions	Yield
With tert.-butylhydroperoxide; tetra-(n-butyl)ammonium iodide; acetic acid In acetonitrile at 80℃; for 16h; Inert atmosphere; Microwave irradiation;	93%

2-Ketopiperazine (5625-67-2) + N-tert-butyloxycarbonyl-S-trityl-L-cysteine (21947-98-8, 87494-13-1) → (R)-tert-butyl 1-oxo-1-(3-oxopiperazin-1-yl)-3-(tritylthio)propan-2-ylcarbamate

Conditions	Yield
Stage #1: N-tert-butyloxycarbonyl-S-trityl-L-cysteine With dicyclohexyl-carbodiimide In dichloromethane at 20℃; for 0.5h; Inert atmosphere; Stage #2: 2-Ketopiperazine With N-ethyl-N,N-diisopropylamine In dichloromethane at 20℃; for 48h; Inert atmosphere;	93%

2-Ketopiperazine (5625-67-2) + 2-Naphthalenesulfonyl chloride (93-11-8) → 4-(naphthalene-2-sulfonyl)-piperazin-2-one (239072-77-6)

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In dichloromethane for 0.5h;	92.5%
With triethylamine In tetrahydrofuran; N,N-dimethyl-formamide

2-Ketopiperazine (5625-67-2) + 4-(3-(4-cyanophenyl)imidazo[1,2-a]pyridin-6-yl)benzoic acid (1464155-72-3) → 4-(6-(4-(3-oxopiperazine-1-carbonyl)phenyl)imidazo[1,2-a]pyridin-3-yl)benzonitrile (1464151-39-0)

Conditions	Yield
With 4-methyl-morpholine; HATU In N,N-dimethyl-formamide at 20℃; for 18h; Inert atmosphere;	92%
With 4-methyl-morpholine; N-[(dimethylamino)-3-oxo-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl-methylene]-N-methylmethanaminium hexafluorophosphate In N,N-dimethyl-formamide at 20℃; for 18h; Inert atmosphere;	92%

Upstream product

• 24123-13-5 N-(2-Aminoethyl)glycinethylester 
• 105-39-5 chloroacetic acid ethyl ester 
• 76003-29-7 4-(t-butyloxycarbonyl)piperazin-2-one 
• 927-68-4 bromoethyl acetate 
• 623-73-4 diazoacetic acid ethyl ester 
• 107-15-3 ethylenediamine 
• 105-36-2 ethyl bromoacetate 
• 2088943-55-7 N-(2-aminoethyl)-2-chloroacetamide hygrochloride 
• 1247428-43-8 C₄H₉ClN₂O 
• 75-09-2 dichloromethane 
• 584-08-7 potassium carbonate 
• 109-89-7 diethylamine 
• 79-07-2 Chloroacetamide 
• 107-16-4 glycolonitrile 

Downstream Products

• 59701-98-3 3-oxo-piperazine-1-carboxylic acid anilide 
• 24123-14-6 N-(2-Aminoethyl)glycine 
• 76003-29-7 4-(t-butyloxycarbonyl)piperazin-2-one 
• 103237-52-1 Oxociprofloxacin 
• 143722-91-2 1,4-Diacetyl-piperazin-2-one 
• 74011-42-0 Oxonorfloxacin 
• 87939-12-6 Oxoenoxacin 
• 98106-45-7 6-Fluoro-1-(4-fluoro-phenyl)-4-oxo-7-(3-oxo-piperazin-1-yl)-1,4-dihydro-quinoline-3-carboxylic acid 
• 114200-44-1 (benzyloxycarbonyl)-L-proly-L-leucyl-2-oxopiperazine 
• 78818-15-2 4-benzyloxycarbonylpiperazin-2-one 
• 161459-56-9 4-(3-Hydroxy-propyl)-piperazin-2-one 
• 3080-43-1 N,N'-dicyclohexyl-N-(3-nitrobenzoyl)urea 
• 59701-90-5 4-cyclohexyl-1,4-pyrazin-2-one 

Relevant articles and documents

Histamine H3 receptor antagonists with peptidomimetic (keto)piperazine structures to inhibit Aβ oligomerisation

Alzheime?s disease (AD) is the most prominent neurodegenerative disorder with high medical need. Protein-protein-interactions (PPI) interactions have a critical role in AD where β-amyloid structures (Aβ) build toxic oligomers. Design of disease modifying multi target directed ligand (MTDL) has been performed, which disable PPI on the one hand and on the other hand, act as procognitive antagonists at the histamine H3 receptor (H3R). The synthetized compounds are structurally based on peptidomimetic amino acid-like structures mainly as keto, diketo-, or acyl variations of a piperazine moiety connected to an H3R pharmacophore. Most of them showed low nanomolar affinities at H3R and some with promising affinity to Aβ-monomers. The structure–activity relationships (SAR) described offer new possibilities for MTDL with an optimized profile combining symptomatic and potential causal therapeutic approaches in AD.

NH insertion reactions catalyzed by reusable water-soluble ruthenium(II)-hm-phenyloxazoline complex

A water-soluble Ru(II)-hm-pheox complex was efficiently catalyzed NH insertion of EDA with a broad class of amine derivatives in water/ether biphasic medium to deliver the biologically active precursors α-aminoester products with excellent yields (up to >99%). The products were separated by decantation and the catalyst was washed and reused several times (at least 8 times) without any specific loss of its catalytic activity. The plausible mechanism of the reaction was explained. Additionally, In case of ethylene diamine, the NH insertion product could be transformed to biological active piperazinone compound in high yield. The asymmetric version of this catalytic reaction is under investigation.

Enantioselective synthesis of α-secondary and α-tertiary piperazin-2- Ones and piperazines by catalytic asymmetric allylic alkylation

The asymmetric palladium-catalyzed decarboxylative allylic alkylation of differentially N-protected piperazin-2- ones allows the synthesis of a variety of highly enantioenriched tertiary piperazine-2-ones. Deprotection and reduction affords the corresponding tertiary piperazines, which can be employed for the synthesis of medicinally important analogues. The introduction of these chiral tertiary piperazines resulted in imatinib analogues which exhibited comparable antiproliferative activity to that of their corresponding imatinib counterparts.