Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• Scheme 1 occur smoothly with formaldimines 3 derived from aliphatic amines, but in the case of primary aromatic amines harsher reaction conditions are required [6]. To date, no synthesis of 1-alkoxyimidazole N-oxides derived from alkoxyamines (‘hydroxyamine ethers’) has been reported. An alternative

Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid

• Jacqueline Pollini,
• Valentina Bragoni and
• Lukas J. Gooßen

Beilstein J. Org. Chem. 2018, 14, 2737–2744, doi:10.3762/bjoc.14.252

• ][10]. These include aromatic amines as polymers [11][12], cardanol-based phosphates as modifiers for epoxy resins [13], cardanol grafted natural rubber as rubber plasticizers [14], amine-based surfactants [15] and phenol/cardanol-formaldehyde based adhesives [16]. The chemical valorization of

Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles

• James T. Fletcher,
• Matthew D. Hanson,
• Joseph A. Christensen and
• Eric M. Villa

Beilstein J. Org. Chem. 2018, 14, 2098–2105, doi:10.3762/bjoc.14.184

• ortho positions (Table 3, entries 1–4) and reaction rates increased with increasing electron-donating character of para substituents (Table 3, entries 5–7). Reaction rates also increased as the size (and corresponding polarizability) of aromatic amines increased (Table 3, entries 8–10). Similar steric

• directly measuring complex mixtures of aldehyde and imine products resulting from a dynamic combination of condensation, rearrangement and hydrolysis reactions between 1-substituted-4-formyl-1,2,3-triazoles and aromatic amines, additional insight regarding substituent effects on this process was defined

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• . Aliphatic aldehydes gave poor yields, with sterically hindered examples not reacting at all. The author attributed this to the formation of enamines. Under the reported reaction conditions primary aliphatic and aromatic amines all produced imines. The benzamide moiety is somewhat common in biologically

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• desirable due to the commercial accessibility of the reactants (aromatic amines). The diazotization reaction is also a versatile approach, as a wide range of arylamines (bearing various substituents) can be subjected to the process [9]. This reaction’s mechanism is not fully understood, but several

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• (diacetoxyiodo)benzene, [bis(trifluoroacetoxy)iodo]benzene and Koser’s reagent have been used to achieve a variety of spirocyclization reactions under mild reaction conditions. Various hypervalent iodine-catalyzed spirocyclization of functionalized phenols and aromatic amines have been successfully developed

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• coupled with various phenols 152 at the more reactive 7-position under mild reaction conditions in presence of K2CO3 in acetic acid/DMF to give pyrazolo[1,5-a]pyrimidine derivative 153. Various aromatic amines 154 were then coupled at 5-postion under Buchwald–Hartwig conditions to get the desired 5

• , aromatic amines, hydroxylamine hydrochloride, semicarbazide hydrochloride, thiosemicarbazide, hydrazine hydrate and phenyl hydrazine (Scheme 63). Similarly, Farghley et al. [146] reported the reaction of 5-amino-4-nitrosopyrazoles 229 and β-ketonitriles 15 in pyridine for the synthesis of pyrazolo[3,4-b

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

• substrate scope was still need to be expanded. Therefore, more efficient and practical methods were desirable. Trifluoromethylation of aryldiazonium salts (Sandmeyer type trifluoromethylation) Aromatic amines, which are available in great structural diversity, are prevalent chemicals in organic chemistry

• . The amino group can be easily transformed into numerous functional groups including halides or cyano groups, which is known as the Sandmeyer reaction. This transformation contained two steps: Diazotization of aromatic amines led to aryldiazonium salt, followed by conversion of diazonium group into

• target functional groups. Recently, several examples of conversion of anilines into trifluoromethylated arenes, named Sandmeyer type trifluoromethylation, were disclosed. This protocol offered a complementary method for the synthesis of trifluoromethylated arenes from the corresponding aromatic amines

From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• in isolable enol intermediates of type 9 [18]. The carboxylate cannot form in the presence of an acid and therefore decarboxylation does not take place (17 → 18 → 10). The mono- and dicarboxylic acids 10 and 11 are stable and do not decarboxylate easily. However, aromatic amines carrying strongly

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• for the synthesis of 2-aminovinylphosphonium salts 30 by reaction of (formylmethyl)triphenylphosphonium chloride (29) with aromatic amines in isopropanol in yields of 47–91% (Scheme 21). The initially obtained imine form of the product underwent tautomerization to a more stable enamine form, usually

• acetylenedicarboxylic acid diester with triphenylphosphine and aromatic amines such as aniline, p-toluidine, 4-acetylaniline, 4-bromoaniline, 4-nitroaniline, 1-naphthylamine, 2-aminopyridine, and 2-amino-5-bromopyridine in dichloromethane at room temperature in yields of 96–98% (Scheme 45). The resulting ylides 68 were

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

• work-up procedure. Obviously, Olah’s imidoalkylating procedure and other similar imidoalkylating systems using strong acids as catalysts and solvents cannot be applied to aromatics or heteroaromatics of basic character, such as tertiary aromatic amines or azines. In the present paper we report the

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• burst of nucleation takes place and the carbon nuclei grow to partially nanocrystalline CDs with certain hydrophilic functional groups in the surface. Raman, FTIR and XPS data confirmed the presence of aromatic amines, hydroxy and carboxy groups on the CD surface. Subsequently, Liu et al. reported the

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

• (T = 150 °C), is limited to aromatic substrates and could not be applied to compounds bearing ketones or aldehydes as functional groups. In the present work we provide an alternative continuous-flow metal-free methodology for the synthesis of both aliphatic and aromatic amines, which requires

The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

• Faith M. Akwi and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 1987–2004, doi:10.3762/bjoc.12.186

• with an increase in electron donor strength of the coupling compound. This method eliminates the use of alkaline and acidic solutions (Scheme 1). In another method developed by Rahimizadeh et al., ferric hydrogen sulfate was used as a catalyst to synthesize azo compounds from aromatic amines and 2

• this investigation is also presented here in form of simple profile plots. Effect of reaction pH, temperature and flow rate on the reaction conversion Azo coupling reactions involving aromatic amines as coupling agents are carried out in mildly acidic conditions such that a water-soluble protonated

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• development of an efficient ruthenium catalyst for selective oxidation of both aliphatic and aromatic amines to nitriles [22]. The catalytic effectiveness of this ruthenium terpyridine complex was ascribed to the polarization effect of the azulene moiety attached at the terpyridine unit and it was sustained

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

• Bernardas Morkunas,
• Balint Gal,
• Warren R. J. D. Galloway,
• James T. Hodgkinson,
• Brett M. Ibbeson,
• Yaw Sing Tan,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2016, 12, 1428–1433, doi:10.3762/bjoc.12.137

• route towards these derivatives involves coupling of 2 with aromatic amines to generate the corresponding amides, followed by acetal group removal under acidic conditions (Scheme 1) [9]. However, when the product of the reaction of 2 with 3 was treated with TFA, compound 4 was generated (Scheme 1). The

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• and the structure of the dialkyl phosphite and isatin (Scheme 9) [35]. In this way a one-pot three-component reaction between 1-tosylpiperidine-4-one (34), aromatic amines 35 and diethyl phosphonate in the presence of magnesium perchlorate as a catalyst, under neat conditions at 80 °C afforded α

• :05 diastereoisomeric ratio. The same research group found a useful method for the synthesis of isoindolin-1-one-3-phosphonates from aromatic amines [41]. The one-pot reaction of aniline 59 with formylbenzoic acid (55) and dimethyl phosphonate (31) under the above-mentioned conditions at 90 °C

• amines 70 using OSU-6, a novel MCM-41-type hexagonal mesoporous silica, as a catalyst (Scheme 17) [44]. The important advantages of this methodology is that the (3-oxoisoindolin-1-yl)phosphonates 71 are obtained in high yields from benzylic, aliphatic and aromatic amines possessing both, electron

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• concentration of free amine present in the reaction mixture by using the triflate salts of the amines was crucial for obtaining high enantioselectivity. Excess free amine resulted in catalyst deactivation and a racemic background reaction. Electron-rich and neutral aromatic amines added to both acyclic and

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• aromatic formamidines (1a–c) starting from triethyl orthoformate and aromatic amines. Low-temperature lithiation of 1 and addition to achiral (R = Ph) and axially chiral (R2 = BINOL) chlorophosphines R2PCl gave ligands 2 and 3 in excellent yields (Scheme 1) [11]. If the correct stoichiometry is maintained

Radical-mediated dehydrative preparation of cyclic imides using (NH₄)₂S₂O₈–DMSO: application to the synthesis of vernakalant

• Dnyaneshwar N. Garad,
• Subhash D. Tanpure and
• Santosh B. Mhaske

Beilstein J. Org. Chem. 2015, 11, 1008–1016, doi:10.3762/bjoc.11.113

• studied on varyingly substituted aliphatic/aromatic primary amines and saturated/unsaturated cyclic anhydrides. The generalization of the protocol was first studied on succinic anhydrides and various aromatic amines (Table 2, entries 1–10). The reaction works well with aniline, alkyl-substituted aniline

• excellent yield (Table 2, entries 11 and 12). Interestingly, the N-phenyl analogue of Captan, a commercially used fungicide could be synthesized in excellent yield (Table 2, entry 12) [18][19]. The reaction of aromatic amines with unsaturated anhydrides to form maleimides was investigated (Table 3). Aniline

• (OAc)2 (10 mol %), ammonium persulfate (APS) (2 equiv), 1,4-dioxane (0.1 M), DMSO (5% v/v), 100 °C, 3 h in a Schlenk tube). A practical synthesis of vernakalant (11). Optimization studiesa. Imides from substituted/unsubstituted aromatic amines and succinic anhydridesa. Imides from substituted

Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols

• Bianca Rossi,
• Nadia Pastori,
• Simona Prosperini and
• Carlo Punta

Beilstein J. Org. Chem. 2015, 11, 66–73, doi:10.3762/bjoc.11.10

• ketimines and promoting their reactivity towards the nucleophilic addition. The general applicability of the reaction has been demonstrated by reacting different aromatic amines, ketones, ethers and alcohols. This approach provides a new protocol for the simple and convenient synthesis of a wide range of

A facile synthesis of functionalized 7,8-diaza[5]helicenes through an oxidative ring-closure of 1,1’-binaphthalene-2,2’-diamines (BINAMs)

• Youhei Takeda,
• Masato Okazaki,
• Yoshiaki Maruoka and
• Satoshi Minakata

Beilstein J. Org. Chem. 2015, 11, 9–15, doi:10.3762/bjoc.11.2

• with a chlorine-containing oxidant (t-BuOCl) in the presence of a base (2,6-lutidine). In addition the basic physicochemical properties of newly synthesized compounds have been investigated. Keywords: aromatic amines; azahelicenes; cinnolines; halogen; oxidation; Introduction Helicenes, ortho-fused

• develop oxidative transformations of aromatic amines for the construction of diverse aza-containing π-conjugated functional molecules [27][28][29][30], we have recently discovered an iodine-containing oxidant-induced unusual oxidative rearrangement of BINAMs leading exclusively to U-shaped azaacenes

• iodine-containing reagent t-BuOI, which is readily generated in situ from t-BuOCl and NaI, serves as a powerful oxidant for homo- and cross-dimerization of aromatic amines leading to aromatic azo compounds [27][28][30]. However, the employment of t-BuOI as an oxidant for this intramolecular oxidative N=N

One-pot four-component reaction for convenient synthesis of functionalized 1-benzamidospiro[indoline-3,4'-pyridines]

• Chao Wang,
• Yan-Hong Jiang and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2014, 10, 2671–2676, doi:10.3762/bjoc.10.281

• generation of Huisgen’s 1,4-dipoles are aromatic heterocycles such as N-alkylimidazole, pyridine, quinoline, isoquinoline and primary aromatic amines. In recent years, other nitrogen-containing nucleophiles such as hydrazine and arylhydrazines are also used to generate Huisgen’s 1,4-dipoles in domino

Synthesis of α-amino amidines through molecular iodine-catalyzed three-component coupling of isocyanides, aldehydes and amines

• Praveen Reddy Adiyala,
• D. Chandrasekhar,
• Jeevak Sopanrao Kapure,
• Chada Narsimha Reddy and
• Ram Awatar Maurya

Beilstein J. Org. Chem. 2014, 10, 2065–2070, doi:10.3762/bjoc.10.214

• here that aldehydes containing an alkyne moiety yielded the corresponding amidines with similar success (Table 2, entries 17 and 18). With aromatic amines, the reaction was good; with aliphatic amines (for instance benzylamine) the reaction was sluggish and the desired amidine was not obtained. The

• -amino amidines 4 [17]. Conclusion In conclusion, we have developed a simple and clean methodology for the synthesis of substituted α-amino amidines using a three-component coupling of isocyanide, aldehyde, and aromatic amines with molecular iodine as a catalyst. The current strategy provides elegant