294-90-6

Usage

Uses

Used in Medical Imaging:
Cyclen is used as a ligand in the development of MRI contrast agents and other imaging agents, where its ability to selectively bind cations enhances the imaging process.
Used in Analytical Chemistry:
Cyclen is used as a ligand in the development of fluorescent nanosensors for the detection of metal ions, providing a sensitive and selective method for ion analysis.
Used in Chemical Synthesis:
Cyclen can be used as a synthetic precursor in various chemical reactions, contributing to the synthesis of complex organic and inorganic compounds.
Used in Research and Development:
Cyclen's unique properties make it a valuable compound for research and development in various fields, including supramolecular chemistry, coordination chemistry, and materials science.

Synthesis Reference(s)

Journal of the American Chemical Society, 96, p. 2268, 1974 DOI: 10.1021/ja00814a056

Flammability and Explosibility

Notclassified

InChI:InChI=1/C8H20N4/c1-2-10-5-6-12-8-7-11-4-3-9-1/h9-12H,1-8H2/p+4

Synthetic route

tert-butyl 1,4,7,10-tetraazacyclododecane carboxylate (916671-24-4) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With trifluoroacetic acid In dichloromethane for 0.333333h;	100%

cyclen-glyoxal (74199-09-0, 79236-92-3) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With hydrogenchloride; sodium hydroxide; bromine In water; toluene	99.23%
With hydrogenchloride; sodium hydroxide; bromine In water; toluene	99.23%
With hydrogenchloride; bromine In water pH=6;	55%

1,4,7,10-tetraazacyclododecane tetrahydrochloride (10045-25-7) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With hydrogenchloride	95%
With potassium hydroxide In water at 0 - 10℃;	91.3%
With potassium hydroxide
With sodium hydroxide In toluene at 40℃; for 1h; Reflux;	13.77 g
With sodium hydroxide In water; toluene	12 g

C11H13NO2 + 1,5-diamino-3-azapentane (111-40-0) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With 5%-palladium/activated carbon; hydrogen; potassium carbonate In 2-methyltetrahydrofuran at 15℃; for 4h; Reagent/catalyst; Temperature; Solvent;	94.9%

2,3,4,5,6,7,8,8c-octahydro-1H-4a,6a,8a-triaza-2a-azoniacyclopent[fg]acenaphthylene bromide salt → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With potassium hydroxide In water at 100℃; Temperature;	93.2%
With caustic In water for 0.5h; Heating;	88%
With potassium hydroxide In water for 0.5h; Heating;	71%

1,2-Diiodoethane (624-73-7) + ethylenediamine (107-15-3) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With tetrabutylammomium bromide In ethanol at 80℃; for 8h;	88.4%

cyclen tetratosylate (52667-88-6) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With sulfuric acid at 165℃;	88%
Stage #1: cyclen tetratosylate With sulfuric acid at 100℃; for 0.05h; Microwave irradiation; Stage #2: With hydrogenchloride In water Stage #3: With sodium hydroxide In water	87%
With sulfuric acid at 100 - 105℃; Heating; 30-48 h;	85%

1,4,7,10-tetraazatricyclo<8.2.1.14,7>tetradecane-13,14-dione → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With hydrazine hydrate In methanol at 20℃; for 20.5h; Solvent; Temperature; Reflux;	87.21%

1-bromo-2-iodoethane (590-16-9) + ethylenediamine (107-15-3) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With tetrabutylammomium bromide In ethanol at 80℃; for 8h;	86%

ethylenediamine (107-15-3) + ethylene dibromide (106-93-4) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With tetra-(n-butyl)ammonium iodide In ethanol at 80℃; for 8h; Reagent/catalyst; Solvent; Temperature;	85%

ethylenediamine (107-15-3) + 1-Bromo-2-chloroethane (107-04-0) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With tetrabutylammomium bromide In ethanol at 80℃; for 8h;	76.7%

ethylenediamine (107-15-3) + 1,2-dichloro-ethane (107-06-2) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With tetrabutylammomium bromide In ethanol at 80℃; for 8h;	74.4%

C32H36N4O8S4 → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With sulfuric acid at 90℃; for 60h; Large scale;	73%

2,3,5,6,8,9-hexahydrodiimidazo[1,2-a:2′,1′-c]pyrazine → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With lithium aluminium tetrahydride In tetrahydrofuran; toluene at 0 - 130℃; for 1h;	70%
With diisobutylaluminium hydride In toluene for 16h; Cooling with ice; Reflux; Inert atmosphere;	58%
With diisobutylaluminium hydride; sodium fluoride 1) toluene, reflux, 15 h; 2) toluene, water, 0 deg C --> rt; Yield given. Multistep reaction;

cyclen-glyoxal (74199-09-0, 79236-92-3) → ethylenediamine (107-15-3) + 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With ethylenediamine In water	A n/a B 56%

8b-methyldecahydro-2a,4a,6a,8a-tetraazacyclopenta[fg]acenaphthylene → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With hydrogenchloride In water at 80℃; for 12h; Product distribution / selectivity; Heating / reflux;	50%

30%-water sodium hydroxide + cyclen-glyoxal (74199-09-0, 79236-92-3) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
In sulfuric acid; toluene	22%
In sulfuric acid; toluene	22%

7-<2-(1,3-Dioxolan-2-yl)ethyl>-1,4,7,10-tetraazacyclododecane-1-carbaldehyde (137145-78-9) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With water for 0.0833333h; Ambient temperature; pH 1; dealkylating reaction;

cis-octahydro-2a,4a,6a,8a-tetraazacyclopenta[fg]acenaphthylene-3,4-dione (368864-09-9) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With dimethylsulfide borane complex In tetrahydrofuran for 48h; Hydrolysis; Heating;

trans-decahydro-2a,4a,6a,8a-tetraazacyclopenta[fg]acenaphthylene (261921-97-5) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
Stage #1: trans-decahydro-2a,4a,6a,8a-tetraazacyclopenta[fg]acenaphthylene With hydrogenchloride; bromine In water at 20℃; Oxidation; Stage #2: With sodium hydroxide In water for 36h; Hydrolysis; Heating;	1.121 g

C14H24N4 → cyclohexane-1,2-dione (765-87-7) + 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
With hydrogenchloride In water at 60℃; for 6h;

triethylentetramine (112-24-3) → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
Multi-step reaction with 3 steps 1: 90 percent / ethanol / 3 h / 0 °C 2: 50 percent / cesium carbonate / acetonitrile / 96 h / 40 °C 3: hydrochloric acid / H2O / 6 h / 60 °C View Scheme
Multi-step reaction with 3 steps 1: 90 percent / ethanol / 3 h / 0 °C 2: 90 percent / cesium carbonate / acetonitrile / 120 h / 40 °C 3: hydrochloric acid / H2O / 6 h / 60 °C View Scheme
Multi-step reaction with 3 steps 1: 97 percent / Et3N / acetonitrile / 5 h / 20 °C 2: 78 percent / K2CO3 / dimethylformamide / 30 h / 100 °C 3: 33 percent / conc. H2SO4 / 28 h / 115 °C View Scheme

C12H22N4 → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
Multi-step reaction with 2 steps 1: 50 percent / cesium carbonate / acetonitrile / 96 h / 40 °C 2: hydrochloric acid / H2O / 6 h / 60 °C View Scheme
Multi-step reaction with 2 steps 1: 90 percent / cesium carbonate / acetonitrile / 120 h / 40 °C 2: hydrochloric acid / H2O / 6 h / 60 °C View Scheme

Conditions	Yield
Multi-step reaction with 2 steps 1: 78 percent / K2CO3 / dimethylformamide / 30 h / 100 °C 2: 33 percent / conc. H2SO4 / 28 h / 115 °C View Scheme
Multi-step reaction with 2 steps 1: 1.) NaOEt / 1.) EtOH, reflux, 30 min, 2.) DMF, 110 deg C, 24 h 2: 54 percent / 96percent aq. H2SO4 / 72 h / 110 °C View Scheme
Multi-step reaction with 2 steps 1: Bu4NI, 50 percent aq. NaOH / toluene / 10 h / Heating 2: 70 percent / phenol, 30 percent HBr, acetic acid / 14 h / 50 °C View Scheme
Multi-step reaction with 2 steps 1: 86 percent / 5percent NaOH / tetrabutylammonium iodide / H2O; toluene / Heating; 8-10 h 2: 85 percent / conc. H2SO4 / 100 - 105 °C / Heating; 30-48 h View Scheme
Multi-step reaction with 3 steps 1: potassium carbonate / N,N-dimethyl-formamide / 24 h / 35 °C 2: sulfuric acid / water / 24 h / 80 °C 3: sodium hydroxide / water; toluene View Scheme

+ (OMe)2CHCH2-halide

Conditions	Yield
Multi-step reaction with 2 steps 1: 60 percent / ethanol / 15 h 2: BH3*SMe2 / tetrahydrofuran / 48 h / Heating View Scheme

1,4,7,10-Tetrazacyclodecane tetrahydrochloride → 1,4,7,10-tetraazacyclododecan (294-90-6)

Conditions	Yield
In chloroform

oxirane (75-21-8) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1,4,7,10-tetrakis-(2-hydroxyethyl)-1,4,7,10-tetraazacyclododecane (67896-40-6)

Conditions	Yield
In water	100%
In ethanol at 5℃;	69%
In water at 0℃; for 2h;

N,N-dimethyl-formamide dimethyl acetal (4637-24-5) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1,4,7,10-tetraazatricyclo[5.5.1.04,13]tridecane (67705-42-4)

Conditions	Yield
In toluene at 120℃; Cyclization;	100%
at 120℃;	95%
In toluene
In toluene at 90 - 100℃; for 1h;

1,2-epoxytetradecane (3234-28-4) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1-(2-hydroxytetradecyl)-1,4,7-10-tetraazacyclododecane

Conditions	Yield
In ethanol for 120h;	100%
In ethanol

tert-butyl 2,5-dioxopyrrolidin-1-yl carbonate (13139-12-3) + 1,4,7,10-tetraazacyclododecan (294-90-6) → di-tert-butyl-1,4,7,10-tetraazacyclododecane-1,7-dicarboxylate (913542-69-5)

Conditions	Yield
In chloroform at 20℃;	100%
In chloroform	100%
In chloroform at 20℃; for 31h;	100%

N-(Benzyloxycarbonyloxy)succinimide (13139-17-8) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1,4,7,10-tetraaza-cyclododecane-1,7-dicarboxylic acid dibenzyl ester (162148-45-0)

Conditions	Yield
In chloroform at 20℃; for 48h;	100%
In chloroform at 20℃; for 0.5h; Inert atmosphere;	100%
In chloroform at 20℃; for 48h;

benzyl chloroformate (501-53-1) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 4,10-bis((benzyloxy)carbonyl)-4,10-diaza-1,7-diazoniacyclododecane-1,7-diium chloride

Conditions	Yield
In chloroform at 20℃; for 24h; Cooling with ice;	100%
Stage #1: benzyl chloroformate; 1,4,7,10-tetraazacyclododecan In chloroform Cooling with ice; Stage #2: In chloroform at 20℃; for 24h;	100%
In chloroform Cooling with ice;	100%
In chloroform at 0 - 20℃; for 10h;	99%

1,4,7,10-tetraazacyclododecan (294-90-6) + 2-chloro-N-[1-(1-naphthyl)ethyl]acetamide → N-[1-(1-naphthyl)ethyl]-1,4,7,10-tetraazacyclododecane-1-acetamide (1512804-14-6)

Conditions	Yield
With triethylamine In chloroform Cooling; Reflux;	100%

C14H21NO5S2 + 1,4,7,10-tetraazacyclododecan (294-90-6) → C21H37N5O2S

Conditions	Yield
In chloroform at 20℃;	100%

N-iodoacetyl ω-aminocaproic acid methyl ester + 1,4,7,10-tetraazacyclododecan (294-90-6) → C44H80N8O12

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In acetonitrile at 50℃; for 18h;	100%

N-iodoacetyl 3-amino-3-methylbutyric acid methyl ester + 1,4,7,10-tetraazacyclododecan (294-90-6) → C40H72N8O12

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In acetonitrile at 50℃; for 18h;	100%

N-iodoacetyl p-aminomethylbenzoic acid methyl ester + 1,4,7,10-tetraazacyclododecan (294-90-6) → C52H64N8O12

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In acetonitrile at 60℃; for 18h;	100%

formaldehyd (50-00-0) + 1,4,7,10-tetraazacyclododecan (294-90-6) + β-cyanoethylisocyanide → 3,3',3'',3'''-((1,4,7,10-tetrakis((1H-tetrazol-5-yl)methyl)-1,4,7,10-tetraazacyclododecane(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetrakis(methylene))tetrakis(1H-tetrazole-5,1-diyl))tetrapropanenitrile

Conditions	Yield
With trimethylsilylazide In methanol; acetonitrile	100%

1-(3-bromopropyl)-3-carbamoylpyridin-1-ium bromide + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1-(3-(1,4,7,10-tetraazacyclododecan-1-yl)propyl)-3-carbamoylpyridin-1-ium bromide

Conditions	Yield
In N,N-dimethyl-formamide at 20℃; for 0.5h; Inert atmosphere; Sonication;	100%

N-(tert-butoxycarbonyl)-succinimide (41839-96-7) + 1,4,7,10-tetraazacyclododecan (294-90-6) → di-tert-butyl-1,4,7,10-tetraazacyclododecane-1,7-dicarboxylate (913542-69-5)

Conditions	Yield
In chloroform	100%

N-iodoacetyl-Gly-Tyr(t-Bu)-OMe + 1,4,7,10-tetraazacyclododecan (294-90-6) → C80H116N12O20

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In acetonitrile at 70℃; for 24h;	99%

N-iodoacetyl-Lys(Boc)-OMe + 1,4,7,10-tetraazacyclododecan (294-90-6) → C64H116N12O20

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In acetonitrile at 50℃; for 18h;	99%

N-iodoacetyl-Gly-L-Tyr(O-propargyl)-OMe + 1,4,7,10-tetraazacyclododecan (294-90-6) → C72H84N12O20

Conditions	Yield
With N-ethyl-N,N-diisopropylamine In acetonitrile at 70℃; for 18h;	99%

glyoxal trimer dihydrate (4405-13-4) + 1,4,7,10-tetraazacyclododecan (294-90-6) → cyclen-glyoxal (74199-09-0, 79236-92-3)

Conditions	Yield
In methanol at 0℃; for 3h;	99%
In methanol at 0 - 20℃; for 2.5h;	94%
In methanol; water at 20℃; for 3h;	82%

1,4,7,10-tetraazacyclododecan (294-90-6) + 7-(4-bromobutyloxy)-4-methyl-2H-chromen-2-one (70846-42-3) → 1,4,7,10-(7-(4-bromobutoxy)-4-methyl-coumarin) cyclen

Conditions	Yield
With potassium carbonate In acetonitrile Reflux;	98.8%

benzyl bromide (100-39-0) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1-benzyl-1,4,7,10-tetraazacyclododecane (112193-83-6)

Conditions	Yield
Stage #1: 1,4,7,10-tetraazacyclododecan With tris(dimethylamino)borane; sodium hydride In toluene for 4h; Heating; Stage #2: benzyl bromide In toluene at 110℃; for 1h;	98%
In acetonitrile for 1h; Heating;	89%
With sodium carbonate In acetonitrile	89%

Glyoxal (131543-46-9) + 1,4,7,10-tetraazacyclododecan (294-90-6) → cyclen-glyoxal (74199-09-0, 79236-92-3)

Conditions	Yield
In methanol; water at 20℃;	98%
In methanol; water at 20℃; for 2h;	95%
In water; acetonitrile	91%

chloroformic acid ethyl ester (541-41-3) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1,7-bis(ethoxycarbonyl)-1,4,7,10-tetraazacyclododecane (162148-43-8)

Conditions	Yield
With pH 2-3	98%
With hydrogenchloride for 24h;	40%
pH=2.5; Acylation;
Stage #1: chloroformic acid ethyl ester; 1,4,7,10-tetraazacyclododecan pH=2 - 3; Stage #2: With sodium hydroxide In water

benzyl chloroformate (501-53-1) + 1,4,7,10-tetraazacyclododecan (294-90-6) → 1,4,7,10-tetraaza-cyclododecane-1,7-dicarboxylic acid dibenzyl ester (162148-45-0)

Conditions	Yield
In ethanol for 24h;	98%
Stage #1: benzyl chloroformate; 1,4,7,10-tetraazacyclododecan In chloroform; water at 0 - 20℃; for 10h; Stage #2: With sodium hydroxide In chloroform	98%
In chloroform	98%

1,4,7,10-tetraazacyclododecan (294-90-6) + 2,4-bis(bromomethyl)-1,3,5-triethyl benzene (190779-61-4) → 1,1′-((2,4,6-triethyl-1,3-phenylene)bis(methylene))bis(1,4,7,10-tetraazacyclo-dodecane)

Conditions	Yield
With triethylamine In chloroform at 20℃; for 121.5h; Inert atmosphere;	98%

C13H13ClN2O3 + 1,4,7,10-tetraazacyclododecan (294-90-6) → C21H32N6O3

Conditions	Yield
In chloroform; N,N-dimethyl-formamide at 20℃;	97%
With potassium carbonate In chloroform; N,N-dimethyl-formamide at 20℃; for 24h;	320 mg

1,4,7,10-tetraazacyclododecan (294-90-6) + oxalic acid diethyl ester (95-92-1) → 1,4,7,10-Tetraazabicyclo[8.2.2]tetradecane-11,12-dione (260410-34-2)

Conditions	Yield
In ethanol for 48h; Acylation;	96%
In ethanol at 20℃; for 72h;	93%
In ethanol
In ethanol for 24h; Reflux;

1,4,7,10-tetraazacyclododecan (294-90-6) + [4-(2-chloro-acetylamino)-butyl]-carbamic acid tert-butyl ester (133264-58-1) → [4-(2-{4,7,10-tris-[(4-tert-butoxycarbonylamino-butylcarbamoyl)-methyl]-1,4,7,10-tetraaza-cyclododec-1-yl}-acetylamino)-butyl]-carbamic acid tert-butyl ester (913972-24-4)

Conditions	Yield
With caesium carbonate; potassium iodide In acetonitrile for 120h; Heating;	96%

Upstream product

• 52667-88-6 cyclen tetratosylate 
• 261921-97-5 trans-decahydro-2a,4a,6a,8a-tetraazacyclopenta[fg]acenaphthylene 
• 112-24-3 triethylentetramine 
• 137145-78-9 7-<2-(1,3-Dioxolan-2-yl)ethyl>-1,4,7,10-tetraazacyclododecane-1-carbaldehyde 
• 10045-25-7 1,4,7,10-tetraazacyclododecane tetrahydrochloride 
• 293302-59-7 3C₁₀H₁₈N₄*4H₃O₄P 
• 24368-15-8 1,1'-(1,2-ethanediyl)di(2-imidazolidinone) 
• 111-40-0 3-azapentane-1,5-diamine 
• 590-16-9 1-bromo-2-iodoethane 
• 107-15-3 ethylenediamine 
• 107-04-0 1-Bromo-2-chloroethane 
• 107-06-2 1,2-dichloro-ethane 
• 624-73-7 1,2-Diiodoethane 
• 106-93-4 ethylene dibromide 

Downstream Products

• 112193-83-6 1-benzyl-1,4,7,10-tetraazacyclododecane 
• 244219-73-6 (1,4,7,10-tetraaza-cyclododec-1-yl)-acetic acid benzyl ester 
• 67705-42-4 1,4,7,10-tetrazatricyclo[5.5.1.0]tridecane 
• 134448-29-6 1,7-bis(4-toluenesulphonyl)-1,4,7,10-tetraazacyclododecane 
• 105855-71-8 1,4-bis(4-toluenesulphonyl)-1,4,7,10-tetraazacyclododecane 
• 289719-40-0 1-tosyl-1,4,7,10-tetraazacyclododecane 
• 273218-72-7 1-phenyl-1,4,7,10-tetraazacyclododecane 
• 748185-90-2 1,7-bis(benzyloxycarbonyl)-4-(9-phenanthrenylmethyl)-10-(12-tetrahydropyran-2-yloxydodecyl)-1,4,7,10-tetraazacyclododecane 
• 748185-89-9 1,7-bis(benzyloxycarbonyl)-4-(6-fluoro-2-quinolinylmethyl)-10-(12-tetrahydro-2H-pyran-2-yloxydodecyl)-1,4,7,10-tetraazacyclododecane 
• 748185-87-7 1,7-bis(benzyloxycarbonyl)-4,10-bis(6-fluoro-2-quinolinylmethyl)-1,4,7,10-tetraazacyclododecane 
• 748185-88-8 1,7-bis(benzyloxycarbonyl)-4-(9-phenanthrenylmethyl)-1,4,7,10-tetraazacyclododecane 
• 748185-86-6 1,7-bis(benzyloxycarbonyl)-4-(6-fluoro-2-quinolinylmethyl)-1,4,7,10-tetraazacyclododecane 
• 141794-34-5 1-triphenylmethyl-1,4,7,10-tetraazacyclododecane 
• 845962-50-7 4-(4,7,10-tris-tert-butoxycarbonylmethyl-1,4,7,10tetraaza-cyclododec-1-ylmethyl)-benzoic acid methyl ester 

Relevant academic research and scientific papers

Preparation and animal biodistribution of 166Ho labeled DOTA for possible use in intravascular radiation therapy (IVRT)

Owing to its favorable decay characteristics (T1/2 = 27 h, Eβ(max) = 1.85 MeV, Eγ = 81 keV) and its availability with a specific activity of 3.74.4GBq/mg from a moderate flux reactor, 166Ho can be considered as a potential radionuclide for intravascular radiation therapy (IVRT) using liquid-filled balloons. In the present work, studies on the use of 166Ho labeled 1,4,7,10- tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) as a possible agent for IVRT for the prevention of restenosis has been initiated. 166Ho was obtained by irradiating natural Ho2O3 powder and DOTA was synthesized by a multistep procedure. The optimum protocol of radiolabeling of DOTA with 166Ho was achieved by varying different reaction parameters. The complex was found to retain its stability for 7 days at room temperature. Bioevaluation studies carried out in Wistar rats showed that >95% of the injected activity was excreted within 3 h p.i. with almost no retention in any major organ. Both radiochemical and biological studies showed that 166Ho labeled DOTA can be further explored as a potential agent for IVRT. Copyright

A copper-cyclen coordination complex associated with a polyoxometalate anion: Synthesis, crystal structure and electrochemistry of [Cu(cyclen)(MeCN)] [W6O19]

The reaction between Cu(NO3)2?3H2O and a tetra-aza macrocycle, more specifically, cyclen in 1:1 MeCN-MeOH solvent mixture forms a Cu2+-cyclen coordination complex in situ, that has been reacted with an isopolyanion [W6O19]2- in a slow diffusion technique, resulting in the isolation of an ion-pair solid [Cu(cyclen)(MeCN)][W6O19] (1). Single crystal structural investigation on 1 shows a square pyramidal geometry around the metal centre (copper ion) with an axially bound MeCN solvent molecule. The title compound 1 is the first crystallographically characterized ion-pair compound, in which a transition metal coordination complex of a tetra-aza-crown ether (cyclen) has been associated with a polyoxometalate cluster anion. This communication deals with synthesis, spectroscopic, structural and electrochemical analyses of compound 1.

Isomerization kinetics of lanthanide(III) complexes with the pendant-arm macrocyclic ligand 1,4,7,10-tetrakis(2-hydroxyethyl)-1,4,7,10-tetraazacyclododecane

The 13C and 1H NMR spectra of the complexes of LaIII, EuIII and LuIII with 1,4,7,10-tetrakis(2-hydroxyethyl)-1,4,7,10-tetraazacyclododecane (L1) in acetonitrile or methanol indicated the presence of two enantiomers the interconversion of which proceeds through both a ring inversion and a rearrangement of the pendant arms. The following kinetic parameters were extracted from temperature-dependent 13C NMR spectra for the ring inversion in [LaL1]3+, [EuL1]3+, [LuL1]3+ in CD3OD and [EuL1]3+ in CD3CN:k(298 K) = 1396, 1055, 1288 and 880 s-1; ΔH? = 37.6, 41.1, 48.2 and 47.7 kJ mol-1; ΔS? = -58.5, -49.2, -23.8 and -28.4 J K-1 mol-1, respectively. The lanthanide(III) substitution induces a continuous variation of the kinetic parameters, implying the same pathway for the enantiomerization. The behaviour of [LnL1]3+ in solution is compared with that of complexes with similar 12-membered tetraaza macrocycles bearing pendant arms.

A practical synthesis of 1,4,7,10-tetraazacyclododecane, a pivotal precursor for MRI contrast agents

A practical preparation of the versatile macrocycle 1,4,7,10- tetraazacyclododecane (cyclen) was developed starting from cheap and easily available starting materials as ethylenediamine and glyoxal.

A microcalorimetric determination of the enthalpies of formation in solution of nickel(II) complexes with tetraaza macrocyclic ligands of varying size

The enthalpies of formation of nickel complexes with tetraaza macrocyclic ligands of varying ring size, from 12 to 15 members, have been determined by destroying the complexes in aqueous solution with alkaline cyanide. The octahedral-square-planar equilibria have been investigated, and the results are presented as ΔH° for both octahedral, blue and, when possible, square-planar, yellow species. Like the Cu(II) system, the blue, octahedral series exhibits a maximum in ΔH° with [14]aneN4. This is discussed in terms of the relative size of the ligand and the metal ion. The unexpected reversal of ΔH° for the two square-planar complexes is rationalized in terms of expected ligand transformations.

A new, facile synthesis of 1,4,7,10-tetraazacyclododecane: Cyclen

This report outlines a new and efficient synthesis of cyclen (1,4,7,10-tetraazacyclododecane, 1) utilizing bis-imidazoline, 6 (1,1′-ethylenedi-2-imidazoline), with 1,2-dibromoethane. General conditions were developed, allowing for the simple, three-step synthesis of 1 at the multigram scale with an isolated overall yield approaching 65%. The cyclization of 6 produced by the condensation of triethylene tetraamine (TETA) with N,N-dimethylformamide dimethyl acetal, gave the twelve membered, imidazolinium, cyclized intermediate bromide salt, 7 (2,3,4,5,6,7,8,8c-octahydro-1H 4a,6a,8a-triaza-2a-azoniacyclopent[fg]acenaphthylene), which hydrolyzed to 1 with the use of hot, aqueous caustic. Hydrolysis of 7 under milder conditions formed the 1,4,7,10-tetraazabicyclo[8.2.1]-tridecan-13-one (20). Mechanistically, the formation of 7 may be rationalized as involving a diaminocarbene that undergoes an intramolecular carbon-hydrogen insertion.

Preparation method of cyclen and intermediate thereof

The invention discloses a preparation method of cyclen and an intermediate thereof, specifically a preparation method of a compound as shown in a formula 4. The method comprises the following step: in water, carrying out a reduction reaction as shown in the specification on a compound as shown in a formula 3 and hydrazine hydrate, wherein X is phosphoric acid or sulfuric acid, when X is phosphoric acid, n is 4/3, and when X is sulfuric acid, n is 2. The preparation method has the advantages of low cost, simple operation, easy purification of intermediates and products, high yield and purity, and suitableness for industrial production.

DINUCLEATING LIGAND OR DINUCLEAR METAL COMPLEX

To provide a metal complex that has high cancer cell toxicity and has DNA target and cyclen.SOLUTION: The present disclosure provides a dinuclear metal complex represented by the following formula (IV).SELECTED DRAWING: None

Novel synthesis method of 1, 4, 7, 10-tetraazacyclododecane

The invention provides a novel synthesis method of 1, 4, 7, 10-tetraazacyclododecane. The 1, 4, 7, 10-tetraazacyclododecane has important application in biomedicine and molecular biology, molecular recognition, catalysis, enzyme chemistry, supramolecular chemistry, hydrogen storage materials and other main surfaces. The preparation method comprises the following steps of: reacting triethylene tetramine and urea serving as initial raw materials to generate ethylene bis-imidazolinone (hereinafter referred to as bis-imidazolinone), carrying out condensation reaction on the raw material and 1, 2-dihalogenated ethane to generate 1, 4-keto-7, 10-keto-1, 4, 7, 10-tetraazacyclododecan (hereinafter referred to as diketone cyclododecane), and preparing 1, 4, 7, 10-tetraazacyclododecane by hydrolysis. According to the method, the product with the gas chromatography content of 99% or above is obtained at the highest total yield of 74.97%. The method has the advantages of high atom utilization rate, few reaction steps, simplicity, easiness in control, high yield and the like, and is a new process route representing clean and efficient production.

Preparation method of high-purity cycleanine

The invention discloses a preparation method of high-purity cycleanine. Diethylenetriamine and N-benzyl diacetaldehyde amine are used as main raw materials, a drying agent is added, generated water isabsorbed, the generation of imine is promoted, meanwhile, hydrogen is introduced to rapidly reduce the imine, the decomposition of imine is avoided, and the reaction is more thorough. The method is simple in step, low in cost, high in yield, low in equipment requirement, environmentally friendly and suitable for industrial production.