Structural features of neutral and cationic cyclams

Alves, Luís G.; Duarte, M. Teresa; Martins, Ana M.

doi:10.1016/j.molstruc.2015.05.037

Cited by 11 publications

(12 citation statements)

References 43 publications

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“…Thus, the isolation of compound 2 was facile, and was produced in an almost quantitative yield. Subsequent removal of the methylene bridges in basic media gave compound 3, analytical data for which matched existing literature data [21,22]. Subsequent N-alkylation with 2-hydroxy-3,5-di-tert-butylbenzyl was facilitated via an established Mannich procedure [14] by using formaldehyde and 2,4-di-tert-butylphenol to give compound 4 in 70% yield.…”

Section: Synthesis and Characterisation Of The Title Compoundsupporting

confidence: 61%

1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane

Leiva

Kaur

Benjamin

et al. 2017

Molbank

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A cyclam (1,4,8,11-tetraazacyclotetradecane)-based macrocycle bearing two benzyl and two 2-hydroxy-3,5-di-tert-butylbenzyl pendent arms was synthesized and characterized using spectroscopic techniques and single crystal X-ray diffraction. The macrocycle crystallizes in the triclinic space group P-1, with the asymmetric unit containing one-half of the molecule. The structure is stabilized by hydrogen-bonding which exists between the phenolic protons and the nitrogen atoms of the macrocyclic ring. The presence of this hydrogen bonding is observed in the 1 H-NMR due to the deshielded nature of the phenolic OH peak (δ 9.99). Cyclic voltammetry of the ligand revealed a single quasi-reversible peak at −0.58 V (E pc = −0.48 V and E pa = −0.68 V), which is due to the electrochemical oxidation of the phenol to the phenoxyl radical.

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Section: Synthesis and Characterisation Of The Title Compoundsupporting

confidence: 61%

1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane

Leiva

Kaur

Benjamin

et al. 2017

Molbank

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“…The 13 C{ 1 H} NMR spectra display five different resonances for the macrocycle backbone and one set of resonances that corresponds to the benzyl moieties. The proton and carbon NMR spectra of 6-10 are similar to those obtained for other trans-disubstituted cyclams already reported and do not deserve further comment [23][24][25].…”

Section: Resultssupporting

confidence: 80%

“…The preparation of trans-disubstituted cyclams of general formula H 2 Bn 2 Cyclam (Bn = PhCH 2 , 6, 4-CF3 PhCH 2 , 7, 4-CH3 PhCH 2 , 8, 4-CF3CH2 PhCH 2 , 9, and 3-CF3 PhCH2, 10) was attained through a standard procedure that involves the reaction of 1,4,8,11-tetraazatriciclo[9.3.1.14,8]hexadecane with 2 equiv. of the suitable benzyl bromide, followed by basic hydrolysis [23][24][25].…”

mentioning

confidence: 99%

Investigations into the Structure/Antibacterial Activity Relationships of Cyclam and Cyclen Derivatives

Alves¹,

Portel

Sousa

et al. 2019

Antibiotics

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A series of cyclam- and cyclen-derived salts are described in the present work; they were designed specifically to gain insights into their structure and antibacterial activity towards Staphylococcus aureus and Escherichia coli, used respectively, as Gram-positive and Gram-negative model organisms. The newly synthesized compounds are monosubstituted and trans-disubstituted tetraazamacrocycles that display benzyl, methylbenzyl, trifluoromethylbenzyl, or trifluoroethylbenzyl substituents appended on the nitrogen atoms of the macrocyclic ring. The results obtained show that the chemical nature, polarity, and substitution patterns of the benzyl groups, as well as the number of pendant arms, are critical parameters for the antibacterial activity of the cyclam-based salts. The most active compounds against both bacterial strains were the trans-disubstituted cyclam salts displaying CF3 groups in the para-position of the aromatic rings of the macrocyclic pendant arms. The analogous cyclen species presents a lower activity, revealing that the size of the macrocyclic backbone is an important requirement for the antibacterial activity of the tetraazamacrocycles. The nature of the anionic counterparts present on the salts was found to play a minor role in the antibacterial activity.

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“…General Compounds 1a and 1b were prepared according to procedures described in the literature. [26][27][28] All other reagents were of commercial grade and used without further purification. NMR spectra were recorded on aBruker AvanceII300 MHz spectrometer at 296 K, referenced internally to residual protonated solvent ( 1 H) or solvent ( 13 C) resonances, and reported relative to tetramethylsilane (d = 0ppm).…”

Section: Methodsmentioning

confidence: 99%

“…The trans-disubstituted cyclam derivatives H 2 (PhCH 2 ) 2 Cyclam (1a)a nd H 2 ( 4-CF 3 PhCH 2 ) 2 Cyclam (1b)r eact with an excesso fm ethyl acrylate to give the tetrasubstituted species( MeOOCCH 2 CH 2 ) 2 (PhCH 2 ) 2 Cyclam (2a)a nd (MeOOCCH 2 CH 2 ) 2 ( 4-CF 3 PhCH 2 ) 2 Cyclam (2b), respectively New cyclam derivatives (HOCH 2 CH 2 CH 2 ) 2 (PhCH 2 ) 2 Cyclam and (HOCH 2 CH 2 CH 2 ) 2 ( 4-CF 3 PhCH 2 ) 2 Cyclam, as well as their Cu II 13 CNMR spectra of compounds 2 and 3 reveal C 2v symmetry in solution,a so bserved for the parentd isubstituted compounds 1 (see Figures S1-S4 in the Supporting Information). [26][27][28] The 1 HNMR spectra reveal fivem ultiplets corresponding to the methylene protons of the macrocycle backbone, whichi ntegrate to four protons each. The a-a nd b-CH 2 protons of the pendant arms appear between d = 3.47 and 2.35 ppm in compounds 2.T hese resonances are shifted to high field in 3,a nd additional multipletsf or the g-CH 2 protons are observed in the range of d = 3.70 to 3.64 ppm.…”

Section: Chemical Studiesmentioning

confidence: 99%

New Cyclams and Their Copper(II) and Iron(III) Complexes: Synthesis and Potential Application as Anticancer Agents

et al. 2019

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New cyclam derivatives (HOCH2CH2CH2)2(PhCH2)2Cyclam and (HOCH2CH2CH2)2(4-CF3 PhCH2)2Cyclam, as well as their CuII and FeIII complexes, were synthesized and characterized and their stability in cellular media was assessed. The cytotoxic effect of all compounds was examined on human cervical cancer (HeLa) cells, revealing strong anticancer activity. After 24 h, only complexes with the (HOCH2CH2CH2)2(4-CF3 PhCH2)2Cyclam ligand are cytotoxic, whereas after incubation for 72 h all compounds show significant antiproliferative effects. Notably, compounds containing 4-CF3 PhCH2 pendant arms on the cyclam ring revealed the most activity, with cytotoxicity values up to 12 times higher than those of cisplatin. All metal complexes seem to induce cell death through the formation of reactive oxygen species.

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Structural features of neutral and cationic cyclams

Cited by 11 publications

References 43 publications

1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane

1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane

Investigations into the Structure/Antibacterial Activity Relationships of Cyclam and Cyclen Derivatives

New Cyclams and Their Copper(II) and Iron(III) Complexes: Synthesis and Potential Application as Anticancer Agents

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