Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin

• Anna R. Bockman and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46

• relevant pteridine derivatives. Reactions which expedite the development of new pterins are thus of great importance. Through a dual role of diazabicycloundecene (DBU), 7-carboxymethylpterin is converted to the soluble DBU salt, with additional DBU promoting an ester-to-amide transformation. We have

• -bonding substituents like a β-hydroxy group. As such, the DBU amidation of 7-CMP can be viewed as an essential tool for heterocyclic chemists. The dual role of DBU in the amidation of 7-CMP. Role of a β-hydroxy group in aiding the amidation reaction. Pseudo-first order kinetics for representative amines

Microwave-assisted synthesis of 2-substituted 4,5,6,7-tetrahydro-1,3-thiazepines from 4-aminobutanol

• María C. Mollo,
• Natalia B. Kilimciler,
• Juan A. Bisceglia and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2020, 16, 32–38, doi:10.3762/bjoc.16.5

• -toxic and environmentally safe. These reagents play a dual role, as they enhance the electrophilicity of nitriles, carbonyls and carbinols, and can also react irreversibly with water. Unlike PPA, a Brønsted acid incompatible with some acid-sensitive functionalities, PPE and PPSE are aprotic and mild

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups

• Nadia Gruber,
• Jimena E. Díaz and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2018, 14, 2510–2519, doi:10.3762/bjoc.14.227

• involves a nucleophilic attack of the arylamino group on the amide carbonyl followed by H2O elimination (Scheme 3) [90]. In such processes, PPSE would play a dual role, activating the amide towards the nucleophilic attack and acting as water scavenger. However, deactivated arylamino groups such as 2/4

Bi-mediated allylation of aldehydes in [bmim][Br]: a mechanistic investigation

• Mrunesh Koli,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2018, 14, 2198–2203, doi:10.3762/bjoc.14.193

• temperature ionic liquid (RTIL), [bmim][Br] has been found to be a superior medium for the Bi-mediated Barbier-type allylation of aldehydes compared to other conventional solvents. It plays the dual role of a solvent and a metal activator enabling higher yields of the products in a shorter reaction time using

Bromide-assisted chemoselective Heck reaction of 3-bromoindazoles under high-speed ball-milling conditions: synthesis of axitinib

• Jingbo Yu,
• Zikun Hong,
• Xinjie Yang,
• Yu Jiang,
• Zhijiang Jiang and
• Weike Su

Beilstein J. Org. Chem. 2018, 14, 786–795, doi:10.3762/bjoc.14.66

• synthesis of 3-vinylindazoles has been developed by sophisticated tuning of the chemical and mechanical parameters under ball-milling conditions. The reaction pathway was comprehensively studied, revealing the bromide salts to play a dual role by not only suppressing the dehalogenation of 3-bromoindazoles

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• . In the case of unsymmetrical biaryl substrates, mixtures of regioisomers at C4 and C5 were obtained (Scheme 48). In the reaction mechanism, PIFA played a dual role in the activation of the arene via a π-complex and in the generation of the CF3 radical from CF3SO2Na. More recently, Maruoka and co

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• derivatives 2-ethyl- and 2-benzylthiotetrazole [8] or 4,5-dicyanoimidazole [9]. The activator has a dual role donating a proton to the departing dialkylamino group and attacking as an anionic species on phosphorus [10]. Nucleoside H-phosphonates are, in turn, converted in situ to reactive mixed anhydrides

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• oligosaccharide acceptor and GDP lead to the understanding of the FUT1 mechanism [40]. Carbohydrate esterases: Carbohydrate esterases perform the de-O or de-N-acylation of carbohydrates. From a mechanistic point of view, this family of enzymes is divided into two classes, according to the dual role played by the

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• ) [36]. In this reaction system, non-toxic and cheap PEG-400 played a dual role as both ligand and solvent. The effective catalytic system could convert aryl iodide to phenols in high yields within 5 hours at 100 °C. The conversion of aryl bromides bearing either an electron-donating group or an

Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

• Sophie Letort,
• Michaël Bosco,
• Benedetta Cornelio,
• Frédérique Brégier,
• Sébastien Daulon,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2017, 13, 417–427, doi:10.3762/bjoc.13.45

• , cyclosarin or tabun (Figure 1) [23][24][25][26][27][28][29][30]. In fact, these β-CD derivatives play a dual role in this process: the macrocycle traps the organophosphorus whilst the bound α nucleophile reacts with the toxic agent leading to a non-toxic derivative. Other scavengers bearing several α

p-Nitrophenyl carbonate promoted ring-opening reactions of DBU and DBN affording lactam carbamates

• Madhuri Vangala and
• Ganesh P Shinde

Beilstein J. Org. Chem. 2016, 12, 2086–2092, doi:10.3762/bjoc.12.197

• 164.3, 141.2 and 126.0 ppm and the upfield shift of C2 of p-nitrophenyl substituent from 122 ppm to 114.4 ppm, suggested that DBN displaced a bromide with the p-nitrophenoxide ion to give compound 14c. Thus, DBN played a dual role in the reaction with 14a – namely as nucleophile and as base giving

Synergistic chiral iminium and palladium catalysis: Highly regio- and enantioselective [3 + 2] annulation reaction of 2-vinylcyclopropanes with enals

• Haipan Zhu,
• Peile Du,
• Jianjun Li,
• Ziyang Liao,
• Guohua Liu,
• Hao Li and
• Wei Wang

Beilstein J. Org. Chem. 2016, 12, 1340–1347, doi:10.3762/bjoc.12.127

• Lewis acid (LA) catalysis strategy (Scheme 1, reaction 2) [49][50][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76]. The iminium catalysis plays an important dual role in the process. The formed iminium ion 4 derived from aldehyde 1 and an amine catalyst activates the C=C

The aminoindanol core as a key scaffold in bifunctional organocatalysts

• Isaac G. Sonsona,
• Eugenia Marqués-López and
• Raquel P. Herrera

Beilstein J. Org. Chem. 2016, 12, 505–523, doi:10.3762/bjoc.12.50

• dual role of catalyst 4 in the activation of the substrates. Thus, in the transition state TS1 (Figure 3a), the substrates and catalyst would form a ternary complex where the thiourea moiety would activate the nitro group of the nitroalkene through hydrogen bonds. Simultaneously, the oxygen atom of the

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• This section will focus on Lewis acid-catalyzed ECA reactions, which employ stabilized nucleophiles such as silyl enol ethers and amines. Chiral Lewis acids play a dual role in these reactions. They activate the Michael acceptors by coordinating with the carbonyl oxygen and they provide a chiral

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

Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

• Meriem Smadhi,
• Sophie de Bentzmann,
• Anne Imberty,
• Marc Gingras,
• Raoudha Abderrahim and
• Peter G. Goekjian

Beilstein J. Org. Chem. 2014, 10, 1981–1990, doi:10.3762/bjoc.10.206

• trithiotriazine-based ligands. Results and Discussion Design of ligands A previous study from our laboratories [30] has shown that low-valent glycoasterisk ligands based on a persulfurated benzene core [31][32] could have a dual role as a probe and as a ligand, due to their phosphorescence [33] and

A new manganese-mediated, cobalt-catalyzed three-component synthesis of (diarylmethyl)sulfonamides

• Antoine Pignon,
• Erwan Le Gall and
• Thierry Martens

Beilstein J. Org. Chem. 2014, 10, 425–431, doi:10.3762/bjoc.10.39

• could be envisaged that the organometallic species II is in fact the organocobalt I. Thus, by transforming I into an inactive organozinc species, zinc salts would hamper the reaction. In the other scenario, in which the transmetallation of I with manganese is very rapid, manganese plays a dual role by

Construction of cyclic enones via gold-catalyzed oxygen transfer reactions

• Leping Liu,
• Bo Xu and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2011, 7, 606–614, doi:10.3762/bjoc.7.71

• case, the gold catalyst exhibited a dual role, namely the activation of alkyne and carbonyl moieties. Yamamoto and co-workers attempted to utilize their protocol to build five-membered cyclic enones, however, when they employed alkynyl ketone 9 as the substrate, the gold catalyst did not show good

Catalysis: transition-state molecular recognition?

• Ian H. Williams

Beilstein J. Org. Chem. 2010, 6, 1026–1034, doi:10.3762/bjoc.6.117

• complex: it attacks the anomeric carbon of the substrate as a nucleophile and displaces the aglycone nucleofuge (Scheme 3). Glu172 is protonated in the reactant complex and plays a dual role of acid/base catalyst: in the glycosylation step it assists formation of the glycosyl-enzyme intermediate by