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

• observed, but only the cleavage was subject to buffer catalysis, viz. general base catalysis. In aqueous solution, second-order dependence of rate on buffer concentration has never been reported. Besides imidazole, guanidine and primary amines have received special interest as cleaving agents of RNA [69

• transfer from the attacking 2´-OH to non-bridging phosphoryl oxygen. Primary amines are, in turn, used to mimic the action of the ε-amino group of lysine. Both guanidine and primary amino groups are basic functions that at physiological pH are present as guanidinium and ammonium ions. These ions tend to

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue

• Romain Sallio,
• Stéphane Lebrun,
• Frédéric Capet,
• Francine Agbossou-Niedercorn,
• Christophe Michon and
• Eric Deniau

Beilstein J. Org. Chem. 2018, 14, 593–602, doi:10.3762/bjoc.14.46

• treatment with trifluoroacetic acid to provide in-situ the corresponding benzoic acids 14a–e and 15. The direct coupling of these functionalized carboxylic acids with chiral benzylic primary amines, (R) or (S)-16 (NH2-CH(Me)Ph) and (R)-17 (NH2CH(Me)p-MeO-C6H4), afforded the required parent amides 6a–d, 7a–e

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• )–H with a electrophilic trifluoromethylation reagent (Togni’s reagent): N,N-Dialkylhydrazones were widely used in organic chemistry, including using as synthetic equivalents of carbonyl compounds, as precursors to substituted hydrazines or primary amines. In 2013, Baudoin and co-workers [53] firstly

Quinone-catalyzed oxidative deformylation: synthesis of imines from amino alcohols

• Xinyun Liu,
• Johnny H. Phan,
• Benjamin J. Haugeberg,
• Shrikant S. Londhe and
• Michael D. Clift

Beilstein J. Org. Chem. 2017, 13, 2895–2901, doi:10.3762/bjoc.13.282

• -catalyzed oxidative deformylation of 1,2-amino alcohols is reported. A wide range of readily accessible amino alcohols and primary amines can be reacted to provide N-protected imine products. The methodology presented provides a novel organocatalytic approach for imine synthesis and demonstrates the

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

One-pot three-component route for the synthesis of S-trifluoromethyl dithiocarbamates using Togni’s reagent

• Azim Ziyaei Halimehjani,
• Martin Dračínský and
• Petr Beier

Beilstein J. Org. Chem. 2017, 13, 2502–2508, doi:10.3762/bjoc.13.247

• rather than an electrophilic trifluoromethylating reagent (Scheme 3). A similar behavior was recently reported by Schoenebeck [37] who showed that isothiocyanates are formed in reactions of primary amines with the (Me4N)SCF3 salt (through a different mechanism). Interesting differences in the NMR spectra

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• , leaving the anhydride unimpaired. For employing 4-phenylnaphtho[2,3-c]furan-1,3-diones 2 as reactive intermediates for the en route conversion with primary amines 3 into 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones 4 the reaction conditions were optimized with 4-phenylnaphtho[2,3-c]furan-1,3-dione (2a) and

• be readily activated with T3P® (n-propylphosphonic acid anhydride) to initiate a domino reaction furnishing 4-arylnaphtho[2,3-c]furan-1,3-diones in excellent yields. These anhydrides can be considered as reactive intermediates for a subsequent imidation with primary amines and, therefore, a one-pot

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• yields. The X-ray analysis showed that products 53 obtained with primary amines are Z-configured whereas those derived from secondary amines, 54, display E-configuration [58] (Scheme 18). The observed different configurations demonstrate the importance of the intramolecular hydrogen-bond between the NH

High-speed vibration-milling-promoted synthesis of symmetrical frameworks containing two or three pyrrole units

• Marco Leonardi,
• Mercedes Villacampa and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2017, 13, 1957–1962, doi:10.3762/bjoc.13.190

• approaches to organic and inorganic synthesis [4][5][6][7][8][9][10][11][12][13]. Indeed, the protocol reported here can be viewed as a generalization of our previously published pyrrole synthesis based on the reaction between primary amines, β-dicarbonyl compounds and ketones, promoted by high-speed

Mechanochemical N-alkylation of imides

• Anamarija Briš,
• Mateja Đud and
• Davor Margetić

Beilstein J. Org. Chem. 2017, 13, 1745–1752, doi:10.3762/bjoc.13.169

• equimolar amount of ethyl bromide resulted in the dominant formation of the mono-alkylated 1-ethyl product 38. The N-alkylated phthalimides 23 and 24, which were prepared in the previous section were employed in solvent-free Gabriel synthesis of primary amines (Scheme 4). In these milling reactions, the

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• -imidoalkylphosphonium salts 5 applied in the Tscherniac–Einhorn-type reaction with aromatic hydrocarbons as a model reaction. The obtained N-(1-arylalkyl)imides can easily be transformed to the corresponding primary 1-arylalkylamines, following the well-known procedures developed for the Gabriel synthesis of primary

• amines. Moreover, this class of compounds is itself attracting significant attention from chemists and biochemists due to their bioactivity as herbicides, and anticancer, anti-inflammatory, analgesic or anticonvulsant agents [26][27][28][29][30][31]. Especially interesting is apremilast (brand name

Sustainable synthesis of 3-substituted phthalides via a catalytic one-pot cascade strategy from 2-formylbenzoic acid with β-keto acids in glycerol

• Lina Jia and
• Fuzhong Han

Beilstein J. Org. Chem. 2017, 13, 1425–1429, doi:10.3762/bjoc.13.139

• efficiency of the reaction, a detailed optimization study was performed with various bases, such as tertiary, secondary and primary amines. When tertiary amines were used as the catalyst, very low yields of 3a were obtained (Table 1, entries 3–5). Unfortunately, a sluggish reaction was observed in the

• presence of pyrrolidine (Table 1, entry 6). Gratifyingly, the desired product was obtained in the presence of primary amines in good yields (Table 1, entries 7–9). In addition, the use of several inorganic bases delivered no catalytic activation (Table 1, entries 10 and 11). Notably, a higher reaction

New tricks of well-known aminoazoles in isocyanide-based multicomponent reactions and antibacterial activity of the compounds synthesized

• Maryna V. Murlykina,
• Maryna N. Kornet,
• Sergey M. Desenko,
• Svetlana V. Shishkina,
• Oleg V. Shishkin,
• Aleksander A. Brazhko,
• Vladimir I. Musatov,
• Erik V. Van der Eycken and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2017, 13, 1050–1063, doi:10.3762/bjoc.13.104

• exocyclic NH2 group and an endocyclic nucleophilic center, they can act both as primary amines and as 1,3-binucleophiles, therefore, their treatments with isocyanides, aldehydes and carboxylic acids may proceed either as Ugi-4CR (aminoazole – primary amine, acid – reagent) or as GBB-3CR (aminoazole – 1,3

• primary amines that allowed using it as an amine component in Ugi-4CR. Particularly, its reaction with aromatic aldehydes 1a–h, phenylpropiolic acid (8) and tert-butylisocyanide (3a) gave peptidomimetics 9 under stirring the starting reagents in MeOH at room temperature for 24 h. In the presence of strong

DMAP-assisted sulfonylation as an efficient step for the methylation of primary amine motifs on solid support

• Johnny N. Naoum,
• Koushik Chandra,
• Dorit Shemesh,
• R. Benny Gerber,
• Chaim Gilon and
• Mattan Hurevich

Beilstein J. Org. Chem. 2017, 13, 806–816, doi:10.3762/bjoc.13.81

• of over-methylated amines. The Mitsunobu–Fukuyama reaction was used for the conversion of primary amines to secondary mono-methylated amines in solution using an alcohol and via temporary protection of the amino group to avoid over methylation [17][18][19][20][21]. This method relies on the

• introduction of the o- or p-nitrobenzenesulfonyl groups to primary amines in the first step. The semi-protected sulfonamides can then undergo a selective mono-methylation via Mitsunobu reaction or by direct methylation. The reaction is completed by the selective removal of the sulfonamide group. Miller and

• additive for sulfonylation of primary amines with o-NBS-Cl for the purpose of N-methylation on solid support. We herein report a DMAP-mediated strategy for the efficient regioselective N-methylation of sterically hindered primary amines as well as less hindered amines on solid support (Figure 1B). Our DFT

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• LiAlH4 (Scheme 2) [37]. Cu-catalyzed amination is known to be a very efficient approach for C–N bond formation [38][39]. The availability of the variety of inexpensive ligands for copper(I) is a crucial benefit in comparison to the Pd-catalyzed variant. Primary amines of different structures can readily

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• . Furthermore, reactions with primary amines like cyclohexylamine and benzylamine produce only the imine and no A3-coupled product, signifying that imines are less efficient than iminium species to initiate further reaction with terminal alkyne. Conclusion In conclusion, the present study demonstrates an

Brønsted acid-mediated cyclization–dehydrosulfonylation/reduction sequences: An easy access to pyrazinoisoquinolines and pyridopyrazines

• Ramana Sreenivasa Rao and
• Chinnasamy Ramaraj Ramanathan

Beilstein J. Org. Chem. 2017, 13, 428–440, doi:10.3762/bjoc.13.46

• -benzenesulfonyliminodiacetic acid and primary amines using carbonyldiimidazole in the presence of a catalytic amount of DMAP at ambient temperature. Piperazine-2,6-diones are successfully transformed to pharmaceutically useful pyridopyrazines or pyrazinoisoquinolines and ene-diamides via an imide carbonyl group activation

• . Results and Discussion Piperazine-2,6-diones are usually synthesized through an Ugi [30] multicomponent approach. The condensation of primary amines with benzyliminodiacetic acid at high temperatures or CDI/THF at reflux leads also to the formation of piperazine-2,6-diones (Scheme 1). Using CDI/THF under

• with primary amines using CDI/DMAP. Formation of ene-diamides 9a–g and pyrazinones 10a–f. Mechanism for the formation of substituted pyrazinones. Synthesis of 3-phenylpyrazinone. Synthesis of 4-N-benzyl-1-N-(aryl/heteroarylethyl)piperazine-2,6-dione. Cyclization of pyrazinoisoquinolines. Synthesis of

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

• Maximilian Maier,
• Magnus S. Schmidt,
• Markus Ringwald and
• Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

• Havis et al. through the dropwise addition of 7 in chloroform to a solution of primary amines such as aminocyclohexane at room temperature [30]. After stirring for 24 hours the resulting diamino hydrobromide was isolated in moderate yield. To avoid quenching/scavenging of the hydrobromide in the later

A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

• Arno Verlee,
• Thomas Heugebaert,
• Tom van der Meer,
• Pavel I. Kerchev,
• Frank Van Breusegem and
• Christian V. Stevens

Beilstein J. Org. Chem. 2017, 13, 303–312, doi:10.3762/bjoc.13.33

• used for a range of m-sulfamoylbenzamide analogues (vide infra). However, if the first reagent (F2) is a secondary amine, the chemoselectivity decreases substantially when the current process is used. Secondary amines are more nucleophilic as compared to primary amines, resulting in a higher percentage

• chemoselectivity was measured by LC–MS and is presented in Table 4. The chemoselectivity varied between 50 and 99%. Apart from the reactions involving 3-fluoroaniline, the chemoselectivity was above 70% for primary amines and above 60% for secondary amines. The side products which are being formed are the double

• account but, the screening of these analogues should already give a good indication which compounds are of interest. Medium throughput synthesis if F2 are primary amines Between each sample a washing step with CH3CN was included to eliminate any side reaction of undesired amines in the system. For the

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

• Yi Lai,
• Zhijian Zong,
• Yujie Tang,
• Weimin Mo,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen,
• Liqun Jin,
• Wen-hua Sun and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

• comprise symmetrical frameworks, such as bipyridine [44][45][46], biimidazole [47][48], and diimine [49][50][51][52][53]. Moreover iminopyridines were attractive for a more straightforward preparation, the condensation of pyridine-2-carboxaldehyde or ketone and the relevant primary amines. By this work a

The synthesis of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides by the microwave-assisted Pudovik reaction

• Erika Bálint,
• Ádám Tajti,
• Anna Ádám,
• István Csontos,
• Konstantin Karaghiosoff,
• Mátyás Czugler,
• Péter Ábrányi-Balogh and
• György Keglevich

Beilstein J. Org. Chem. 2017, 13, 76–86, doi:10.3762/bjoc.13.10

• and α-aryl-α-aminophosphine oxides was synthesized by the microwave-assisted solvent-free addition of dialkyl phosphites and diphenylphosphine oxide, respectively, to imines formed from benzaldehyde derivatives and primary amines. After optimization, the reactivity was mapped, and the fine mechanism

• preparation of new derivatives. Results and Discussion Synthesis of α-aryl-α-aminophosphonates and α-aminophosphine oxides At first, the imine starting materials 1 were prepared by the condensation of benzaldehyde and its chloro-substituted derivatives with primary amines, such as butyl-, cyclohexylamine or

Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane

• Riccardo Porta,
• Alessandra Puglisi,
• Giacomo Colombo,
• Sergio Rossi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2016, 12, 2614–2619, doi:10.3762/bjoc.12.257

• performed for the first time under continuous-flow conditions. Aromatic as well as aliphatic nitro derivatives were converted to the corresponding primary amines in high yields and very short reaction times with no need for purification. The methodology was also extended to the synthesis of two

Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

• Artem N. Semakin,
• Aleksandr O. Kokuev,
• Yulia V. Nelyubina,
• Alexey Yu. Sukhorukov,
• Petr A. Zhmurov,
• Sema L. Ioffe and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2016, 12, 2471–2477, doi:10.3762/bjoc.12.241

• our knowledge, there is only one report on the formation of bishydrazones as undesirable products in reactions of some primary amines with N-tosylhydrazone of o-bromophenacyl bromide [50]. We suppose that extension of the scope of azoalkene–amine coupling to ammonia, primary amines and polyamines

Methylenelactide: vinyl polymerization and spatial reactivity effects

• Judita Britner and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 2378–2389, doi:10.3762/bjoc.12.232

• quantitative amidation reactions with aliphatic primary amines under mild conditions [7]. In the underlying study, we focused on spatial effects with respect to interactions between neighboring lactide rings. Based on these findings, polymer analogous reactions of poly(MLA) with different alcohols were

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• ) [36]. The introduction of the nitroso group through the transformation of pendant functional groups includes the oxidation of primary amines [37][38][39][40][41] (Scheme 4) and hydroxamic acids [42][43][44] (Scheme 5) and the reduction of nitro compounds [45][46][47]. As oxidants for the amino group