Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• heterocyclization reactions by exploiting the electrophilic character of Pd(II) species. Starting from substrates bearing a triple bond and a nucleophile in the appropriate position, a versatile process of heterocyclization can be initiated, resulting in indole derivatives with important properties. Gabriele et al

• %, respectively) in methanol under 90 bar of CO at 100 °C for two hours (Scheme 6). As already seen, triple bonds can be activated by Pd(II) catalysts towards the addition of nucleophiles in the right position, leading to heterocyclization reactions. Taking advantage of this possibility, in the Della Cá group, a

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• equivalents to react with various nucleophilic reagents [90]. In 2014, Heimgartner et al. first developed the condensation reaction of a commercially available fluoral hemiacetal with acylhydrazides to yield trifluoromethylated acylhydrazones, and these fluorinated compounds underwent heterocyclization

• reactions with mercaptoacetic acid and acetic anhydride leading to trifluoromethylated 1,3-thiazolidin-4-ones and 3-acetyl-2,3-dihydro-1,3,4-oxadiazoles, respectively. It was found that the C=N reactivity of the trifluoromethylated acylhydrazones is similar to that of other nitrogen-containing fluorinated

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• electron-donating groups like MeO. Studies to expand even more the scope and the selectivity of such DES-promoted heterocyclization reactions and to elucidate their mechanism are in progress. Experimental General methods Deep eutectic solvents [choline chloride (ChCl)/glycerol (Gly) (1:2 mol/mol); choline

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

• interest as so-called ‘nitrone like’ reagents for the synthesis of more complex, imidazole containing systems (Scheme 1) [6]. These imidazole N-oxides are easily accessible via heterocyclization reactions comprising condensation of α-hydroxyiminoketones 2 with formaldimines 3. The latter are known to exist

Microwave-assisted synthesis of biologically relevant steroidal 17-exo-pyrazol-5'-ones from a norpregnene precursor by a side-chain elongation/heterocyclization sequence

• Gergő Mótyán,
• László Mérai,
• Márton Attila Kiss,
• Zsuzsanna Schelz,
• Izabella Sinka,
• István Zupkó and
• Éva Frank

Beilstein J. Org. Chem. 2018, 14, 2589–2596, doi:10.3762/bjoc.14.236

• heterocyclization reactions were carried out with different substituted phenylhydrazine hydrochlorides 5d–j. All reactions furnished the corresponding 17-exo-heterocycles 6d–j in good to excellent yields (83–92%, Table 1). The electronic features of the substituents on the aromatic ring of 5 had a notable influence

A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

• Dmitry Yu. Vandyshev,
• Khidmet S. Shikhaliev,
• Andrey Yu. Potapov,
• Michael Yu. Krysin,
• Fedor I. Zubkov and
• Lyudmila V. Sapronova

Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252

• itaconimides, four primary adducts 5–8 could result (Scheme 5) based on the well-known fact that the heterocyclization reactions of α,β-unsaturated carbonyl compounds with dinucleophilic reagents typically begin with addition like Michael’s reaction, including heterocyclic dinucleophiles [39][40][41][42

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

• reactions; electron-deficient ethenes; heterocyclization reactions; Michael additions; SET mechanism; Review Introduction Electron-deficient alkenes form an important class of organic compounds, which are of key importance in organic synthesis. The best known representative of this class is

• amines, hydrazine, and carbohydrazides. In some of these reactions, the initially formed adducts, after subsequent elimination of HCN, undergo heterocyclization (see chapter Heterocyclization reactions). The reaction of E-1a with either aqueous ammonia or gaseous NH3 in acetonitrile leads to the enamines

• heterocyclization suggests the E-configuration (see following chapter). Heterocyclization reactions Due to the presence of six electrophilic centers, dialkyl dicyanofumarates E-1 are useful starting materials for reactions with dinucleophilic reagents, which in one-pot procedures lead to diverse heterocyclic

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

• this case, the primary alkylation adducts might be unstable and undergo heterocyclization reactions (on the synthesis of heterocyclic compounds from azoalkenes and diamines see [54][55][56]). Bishydrazones containing clickable groups (like 3) can be introduced into functional molecules or immobilized

Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors

• Ming-Liang Zhang,
• Deng-Feng Yue,
• Zhen-Hua Wang,
• Yuan Luo,
• Xiao-Ying Xu,
• Xiao-Mei Zhang and
• Wei-Cheng Yuan

Beilstein J. Org. Chem. 2016, 12, 295–300, doi:10.3762/bjoc.12.31

• -diones is mainly focused on three-component spiro-heterocyclization reactions [30][31][32]. However, for the catalytic asymmetric transformation, only one example of an aldol reaction of 1H-pyrrole-2,3-diones with ketones has been reported so far (Scheme 1) [33]. Recently, our group developed a chiral

Gold-catalyzed oxycyclization of allenic carbamates: expeditious synthesis of 1,3-oxazin-2-ones

• Benito Alcaide,
• Pedro Almendros,
• M. Teresa Quirós and
• Israel Fernández

Beilstein J. Org. Chem. 2013, 9, 818–826, doi:10.3762/bjoc.9.93

• heterocyclization reactions to afford 1,3-oxazinan-2-ones 3. To increase the molecular diversity by incorporating more 1,3-oxazin-2-ones in the molecule, compound 2g having two allenic carbamate units was used. Notably, bis(allenic carbamate) 2g also undergoes this interesting transformation to give bis(6-methylene

Features of the behavior of 4-amino-5-carboxamido-1,2,3-triazole in multicomponent heterocyclizations with carbonyl compounds

• Eugene S. Gladkov,
• Katerina A. Gura,
• Svetlana M. Sirko,
• Sergey M. Desenko,
• Ulrich Groth and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2012, 8, 2100–2105, doi:10.3762/bjoc.8.236

• polyfunctional aminoazoles that have been studied in heterocyclization reactions [5][6][7][8][20], derivatives of 4-amino-1,2,3-triazole have been less well investigated. There are only a few examples of their heterocyclizations with β-diketones [21], N-cyanomethaneimidates [22], isocyanates [23], chalcones [24

• contain cross-peaks between pyrimidine NH and spiro-carbon, which is also in good correlation with structure 4. Analogous elucidations allowed the structures of compounds 7 and 9 to be established. Conclusion In summary, two types of heterocyclization reactions involving 4-amino-5-carboxamido-1,2,3

Gold-catalyzed heterocyclizations in alkynyl- and allenyl-β-lactams

• Benito Alcaide and
• Pedro Almendros

Beilstein J. Org. Chem. 2011, 7, 622–630, doi:10.3762/bjoc.7.73

• Científicas (CSIC), Juan de la Cierva 3, 28006-Madrid, Spain 10.3762/bjoc.7.73 Abstract New gold-catalyzed methods using the β-lactam scaffold have been recently developed for the synthesis of different sized heterocycles. This overview focuses on heterocyclization reactions of allenic and alkynic β-lactams

• four-membered ring, using the chirality and functionalization of the β-lactam ring as a stereo-controlling element [29][30]. This overview focuses on gold-catalyzed heterocyclization reactions of allenic and alkynic β-lactams which rely on the activation of the allene and alkyne component. The

• scope of these transformations, gold-catalyzed heterocyclization reactions of alkynols to the fused bicyclic systems was also examined. Indeed, treatment of 2-azetidinone-tethered bishomopropargylic alcohol 26 with AuCl3 provided the desired cycloetherification/hydroxylation product 27a in good yield

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• into 5-amino-1-aryl-4-diethoxyphosphoryl-3-halomethylpyrazoles 110. 2,6-Dichloro-4-trifluoromethylphenylhydrazine undergoes this reaction under more drastic conditions, i.e., prolonged refluxing (16–20 h) in carbon tetrachloride (Scheme 31) [73]. Heterocyclization reactions of trifluoromethylcyanovinyl

A facile synthesis and fungicidal activities of 2-(alkylamino)-5,6-dimethylthieno[2,3-d]pyrimidin- 4(3H)-ones

• Yang-Gen Hu,
• Ai-Hua Zheng,
• Xu-Zhi Ruan and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2008, 4, No. 49, doi:10.3762/bjoc.4.49

• carbodiimides, functional groups consisting of the formula N=C=N, able to undergo a plethora of heterocyclization reactions [1][2][3][4][5][6]. At the same time, many heterocycles containing thienopyrimidine system are of great importance for use as potential drugs because of their remarkable biological