Synthetic strategies of phosphonodepsipeptides

• Jiaxi Xu

Beilstein J. Org. Chem. 2021, 17, 461–484, doi:10.3762/bjoc.17.41

• 17 was synthesized via the coupling of methyl N-Cbz-1-aminoethylphosphonochloridate (13b) generated from phosphonic monomethyl ester 12b and methyl (S)-2-hydroxy-3-phenylpropanoate (18) followed by hydrogenolysis. It was further coupled to cyclen to afford various cyclen-containing

• . Structure of 2-hydroxy-2-oxo-3-[(phenoxyacetyl)amino]-1,2-oxaphosphorinane-6-carboxylic acid (16). Synthesis of α-phosphonodepsidipeptides as inhibitors of leucine aminopeptidase. Synthesis of α-phosphonodepsidipeptide 17 as coupling partner for cyclen-containing phosphonodepsipeptides as inhibitors of

Au(III) complexes with tetradentate-cyclam-based ligands

• Ann Christin Reiersølmoen,
• Thomas N. Solvi and
• Anne Fiksdahl

Beilstein J. Org. Chem. 2021, 17, 186–192, doi:10.3762/bjoc.17.18

• -tetraazacyclotetradecane), cyclen (1,4,7,10-tetraazacyclododecane)), ethylenediamine and triethylenetetraamine derivatives. Studies of Au(III)-cyclam modified complexes have been limited to arylated [16] or polymer-bound cyclams for selective uptake of Au(III) from water [17] as well as X-ray crystal structures [18][19

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• cation, forming complexes. Crown ethers also contain a series of derivatives, such as aza-crowns, where the ether oxygen atoms are replaced by amino groups. A well-known tetrazacrown is cyclen. Due to the excellent host–guest properties of crown ethers, they play a very important role in the construction

• photosynthetic reaction center for photosynthesis could be realized. König and co-workers demonstrated the use of a flavin–Zn(II)–cyclen assembly (Figure 4) to convert benzyl alcohol to benzaldehyde upon irradiation [20]. This reaction could be performed in both organic and aqueous phases, with a photooxidation

• quantum yield of 3.8 × 10−2 and 0.4, respectively. In contrast, for flavins without the zinc(II)–cyclen unit, only small amounts of product were observed, and the quantum yield was 30 times lower compared to that of the assembly with the flavin chromophore possessing a binding site. The mechanism may be

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• bearing a Zn2+–cyclen complex (Scheme 7) [78]. The ternary complex of Zn2+, UpU and 6a was shown to be more stable than any of the binary complexes of these species. Within this ternary complex, the triazine core could interact with the phosphodiester linkage and via various tautomeric forms facilitate

• ], the second-order rate constants for the cleavage and isomerization being 1.75∙10−2 L mol−1 s−1 and 1.5∙10−2 L mol−1 s−1 at 90 °C, respectively. The catalysis seems to be base moiety selective, since ApA is not cleaved. It has been suggested that one doubly charged cyclen moiety anchors the catalyst by

• hydrogen bonding to the carbonyl groups of uracil base and the other cyclen serves as an electrophilic catalyst by interacting with the phosphodiester linkage. The tetra- and penta-cations of 2,6-bis(1,4,7,10-tetraazacyclododecan-1-ylmethyl)pyridine (11b) have given similar results. The possible role of

A direct method for the N-tetraalkylation of azamacrocycles

• Andrew J. Counsell,
• Angus T. Jones,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2016, 12, 2457–2461, doi:10.3762/bjoc.12.239

• cyclen has been developed, using a partially miscible aqueous–organic solvent system with propargyl bromide, benzyl bromide, and related halides. The method works most effectively when the reaction mixture is shaken, not stirred. A crystal structure of the N-tetrapropargyl cyclam derivative 1,4,8,11

• -tetra(prop-2-yn-1-yl)-1,4,8,11-tetraazacyclotetradecane diperchlorate is reported. Keywords: azamacrocycles; biphasic system; cyclam; cyclen; N-alkylation; Findings The tetraazamacrocycles cyclam (1) and cyclen (2) have been the subject of considerable interest over many years [1][2][3][4][5][6][7

• reasonable (71% for the tetra n-propyl derivative, 50% for tetra-n-dodecyl), but the scope was not explored beyond these two examples [33]. Fricke et al. have generated cyclen derivatives N-tetraalkylated with long hydrocarbon chains (unbranched C8, C12 and C18 alkyl chains), using n-BuLi to irreversibly