Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• –substrate interface. The mfp's contain up to 27 mol % of DOPA (ʟ-3,4-dihydroxyphenylalanine), which plays a crucial role on mussel adhesion [11]. Although the crucial role of DOPA in mussel adhesion is not fully understood, a prevailing view suggests that DOPA can be oxidized to o-quinones at an acidic pH

• and the quinones react with unoxidized catechols to form o-semiquinone radicals afterwards [12]. The semiquinone radicals can help DOPA adhere onto organic surfaces. At a basic pH, the system is cured and mechanically stabilized through the formation of DOPA-metal coordination bonds. The cohesion of

• the DOPA-metal complex helps mussel adhere onto inorganic surfaces (Scheme 3). 1.2 Conventional radical polymerization Radical polymerization, which IUPAC defines as ‘A chain polymerization in which the kinetic-chain carriers are radicals’ [13], is the most widely used reaction in polymer industry. As

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• , 3,4-dihydroxy-L-phenylalanine (L-DOPA), 4-coumaric acid or caffeic acid. Grisanes. Many fungal spirobenzofuranones contain the grisane (191) moiety as the central structural motif (Scheme 26a). The spiro linkage between the B and C rings is installed by oxidative phenol coupling starting from type II

Adsorption mechanism and valency of catechol-functionalized hyperbranched polyglycerols

• Stefanie Krysiak,
• Qiang Wei,
• Klaus Rischka,
• Andreas Hartwig,
• Rainer Haag and
• Thorsten Hugel

Beilstein J. Org. Chem. 2015, 11, 828–836, doi:10.3762/bjoc.11.92

• -dihydroxyphenylalanine (DOPA, 15–30 mol %) [7][8]. DOPA is formed by posttranslational modification of tyrosine. Mefp 6 is rich in cystein (11 mol %) [6]. It has been found that the DOPA in Mefp 3 and 5 adheres to the surfaces, while the cystein-rich Mefp 6 controls the redox balance and can keep interfacial DOPA in a

• reduced state [5][9]. The byssal plaque also shows strong cohesion through crosslinks. The cysteins can crosslink with DOPA and the oxidized DOPA (semiquinones) can crosslink via radical addition. Furthermore, crosslinking by iron chelate complexes of DOPA improves cohesion [10]. The adhesion of a single

• DOPA to metal oxides was studied with AFM force spectroscopy [11][12][13] and rupture forces of up to 1000 pN were measured. This is on the same order of magnitude compared to forces of around 1400 pN that have been measured for the rupture of covalent bonds [14][15][16]. Besides the strength of the

Synthesis of tripodal catecholates and their immobilization on zinc oxide nanoparticles

• Franziska Klitsche,
• Julian Ramcke,
• Julia Migenda,
• Andreas Hensel,
• Tobias Vossmeyer,
• Horst Weller,
• Silvia Gross and
• Wolfgang Maison

Beilstein J. Org. Chem. 2015, 11, 678–686, doi:10.3762/bjoc.11.77

• ], carboxylates [5] and phosphates [6] as well as phosphonates [7] for metal and metal oxide surfaces. In addition, bifunctional catechols like dopamine or DOPA (L-3,4-dihydroxyphenylalanine, Figure 1B), have received considerable interest as anchor groups for important metal surfaces such as titanium oxide, iron

• consequence of reversible binding at neutral and slightly acidic pH. Multivalent catecholates, such as MAPs or oligo-DOPA, overcome this drawback of simple catecholate derivatives and show increased binding affinities to metal surfaces. They are therefore attractive anchors for durable immobilizations on

• monochromator). A) Schematic drawing of a bifunctional anchor molecule and its immobilization on a nanoparticle (NP); B) tripodal catechol derivative, derived from the native bifunctional anchors dopamine and L-DOPA. Catecholates for the immobilization on ZnO NPs. A) XRD pattern of ZnO NPs obtained by the

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• -dihydroxyphenylalanine (DOPA), many O-acyl side-chain derivatives are directly accessible via a particularly expedient and scalable method not commonly applied until recently. Direct acylation of unprotected hydroxyamino acids with acyl halides or carboxylic anhydrides under appropriately acidic reaction conditions

• more elaborate procedures for chemoselective O-acylation reactions, spur its further development, and finally to chronicle the informative, but poorly documented history of its development. Keywords: amino alcohols; chemoselectivity; DOPA; hydroxyamino acids; hydroxyproline; O-acylation

• Bretschneider and Biemann to the diacetylation of 3,4-dihydroxyphenylalanine (DOPA), opening up for their improved synthesis of poly-DOPA [15]. As part of their influential studies on carbodiimide coupling agents for peptide synthesis, Sheehan, Goodman and Hess reported, in 1956, a chemoselective O-acetylation

Development of peptidomimetic ligands of Pro-Leu-Gly-NH₂ as allosteric modulators of the dopamine D₂ receptor

• Swapna Bhagwanth,
• Ram K. Mishra and
• Rodney L. Johnson

Beilstein J. Org. Chem. 2013, 9, 204–214, doi:10.3762/bjoc.9.24

• pituitary gland [4]. Early on, however, it was found that PLG also possessed significant neuropharmacological activity as a modulator of dopaminergic neurotransmission within the CNS [5], as illustrated by its ability to potentiate the behavioral effects of L-DOPA [6], to enhance the affinity of dopamine