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

• trifluoroacetonitrile imine, are highly versatile in that they react with olefins, acetylenes, dimethyl fumarate, dimethyl maleate, β-diketones, β-keto esters, bicyclic olefins, and potassium isothiocyanate and isocyanate affording the corresponding trifluoromethyl-containing compounds, generally with good yields [51

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• 1,3-dicarbonyl compounds using a catalytic amount of hydrazine hydrate without solvent in a short reaction time (10 min) [14]. Reactions of 2-aminothiophenols with β-keto esters and β-diketones under microwave irradiation (MWI) using basic alumina as heterogeneous catalyst without solvent afforded 4H

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• scope of substrates for both the oximes and the β-diketones. First, we carried out the reactions between phenyl hydroximoyl chlorides 1a–c and 1,3-diketones 2b–e (Figure 3). To ensure completion, all reactions were run for 2 hours instead of 1 hour, regardless of substrates having either electron

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

• Yelong Lei and
• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 70–76, doi:10.3762/bjoc.18.6

• products, ethyl (oxazolin-2-yl)alkanoates 3. Interestingly, the reaction of α-diazo-β-diketones and 2-arylaziridines generated 2-(2-oxoalkylidene)oxazolidines [21], while the current reaction of alkyl α-diazo-β-oxoalkanoates and 2-arylaziridines gave alkyl (oxazolin-2-yl)alkanoates as products, showing

• hydrogen bond. Thus, the tautomerization favors to the left direction, forming D-form products, when α-diazo-β-diketones are as starting materials (R1 = alkyl and aryl), while it predominates to the right direction, generating 2-(alkoxycarbonyl)methyloxazolines as products, when alkyl α-diazo-β

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• reported the use of active methylene compounds as suitable nucleophiles in intramolecular hydroalkylation reactions (Scheme 2) [25]. In the presence of PdCl2(CH3CN)2, the hydroalkylation of β-diketones 1 gave only 6-endo-trig cyclization products 2 in moderate to good yields (Scheme 2). The methodology

• -substituted β-diketones 2a and 2b (61 and 70% yield, respectively). Notably, the unsaturated carbocycles expected from palladium β-hydride elimination were not observed, indicating that an oxidant was not required in the reaction medium to regenerate the Pd(II) species. Later, deuterium-labeling experiments

• . Despite these disadvantages, this Fe(III) hydroalkylation could be carried out in air instead of an inert atmosphere usually required in gold methodologies. More recently, iridium complexes were used as efficient catalysts in intermolecular hydroalkylation reactions between β-diketones and less reactive

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

• Sergey V. Norkov,
• Anton V. Cherkasov,
• Andrey S. Shavyrin,
• Maxim V. Arsenyev,
• Viacheslav A. Kuropatov and
• Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

• ring seems promising since β-diketones as well as o-quinones are known as chelating ligands. The combination of two different chelating sites in the same molecule should give a bifunctional bridging ligand. Such species are interesting from the viewpoint of assembling of ordered structures in a crystal

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• radicals. For example, a number of long-lived diacyl iminoxyl radicals 18 were generated by the action of tetranitromethane [63] or NO2 [64] on the corresponding β-diketones 17 or barbituric acid. The formation and decay of radicals were studied by EPR spectroscopy [64]. The lifetimes of radicals in the

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• best using aromatic aldehydes with both electron-withdrawing and donating substituents in ortho, meta and para-positions. In addition, not only acetoacetates can be employed, but the reaction can be extended to ketones, thioesters, benzoylacetic esters, acetoacetamides, alkylic or cyclic β-diketones

A convenient and practical synthesis of β-diketones bearing linear perfluorinated alkyl groups and a 2-thienyl moiety

• Ilya V. Taydakov,
• Yuliya M. Kreshchenova and
• Ekaterina P. Dolotova

Beilstein J. Org. Chem. 2018, 14, 3106–3111, doi:10.3762/bjoc.14.290

• , Moscow Region, Russian Federation D. Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, Russian Federation 10.3762/bjoc.14.290 Abstract A versatile and robust synthetic protocol for the preparation of β-diketones bearing 2-thienyl and perfluorinated alkyl radicals of

• condensation; copper chelate; β-diketones; perfluorinated esters; thiophene; Introduction Classical β-diketones have been studied for more than a century, and no doubt, they are the most popular O,O-ligands in the coordination chemistry of d- and f-elements [1][2][3]. These compounds are widely used as

• to suppression of multiphonon non-radiative relaxation [7][12][13]. Among all β-diketones, one derivative of thiophene, namely 2-thenoyltrifluoroacetone (Htta, 4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dione), is produced on industrial scale and extensively used in the nuclear fuel separation cycle [14

Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands

• Rebecca Pittkowski and
• Thomas Strassner

Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54

• changing the ancillary ligand from acetylacetonate (R = CH3) to sterically demanding aryl-substituted β-diketones (R = 2,4,6-trimethylphenyl, 2,3,5,6-tetramethylphenyl). The drastically increased quantum yield was accompanied by a shift in the emission color from the deep-blue to the sky-blue spectral

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

• convenient regioselective synthetic methods with mild conditions and good yields of the reactions [40][41]. Aggarwal et al. [42] reported the regiospecific synthesis of 4-trifluoromethyl-1H-pyrazolo[3,4-b]pyridines 18 by the reaction of 5-aminopyrazole 16 with trifluoromethyl-β-diketones 17 in refluxing

• predominant. The keto form 17 results in the formation of 6-trifluoromethylpyrazolo[3,4-b]pyridines 20 by attack of the 5-NH2 group (from 5-aminopyrazole 16) on the more electrophilic carbonyl group attached to CF3 (from trifluoromethyl-β-diketones 17) whereas the enolic form 21 reacts with the less

• -b]pyridine-spiroindolinone nucleus 59 with a high degree of regioselectivity without formation of the regioisomeric pyrazolo[1,5-a]pyrimidine 60 involving three-component reaction of 5-aminopyrazole 16, isatin 54 and cyclic β-diketones 58 in aqueous ethanol with p-TSA as catalyst (Scheme 13

Nucleophilic dearomatization of 4-aza-6-nitrobenzofuroxan by CH acids in the synthesis of pharmacology-oriented compounds

• Alexey M. Starosotnikov,
• Dmitry V. Shkaev,
• Maxim A. Bastrakov,
• Ivan V. Fedyanin,
• Svyatoslav A. Shevelev and
• Igor L. Dalinger

Beilstein J. Org. Chem. 2017, 13, 2854–2861, doi:10.3762/bjoc.13.277

• 10.3762/bjoc.13.277 Abstract 4-Aza-6-nitrobenzofuroxan (ANBF) reacts with 1,3-dicarbonyl compounds and other CH acids to give carbon-bonded 1,4-adducts – 1,4-dihydropyridines fused with furoxan ring. In the case of most acidic β-diketones, which exist mainly in the enol form in polar solvents, the

• -dinitrobenzofuroxan (DNBF) another reaction pathway was observed. DNBF react with β-diketones and even monoketones in DMSO solution to give carbon-bonded σ-adducts in the absence of any added base [15] (Scheme 2). However, DNBF is a typical superelectrophile [16], it reacts very easily with water or methanol without

Curcuminoid–BF₂ complexes: Synthesis, fluorescence and optimization of BF₂ group cleavage

• Henning Weiss,
• Jeannine Reichel,
• Helmar Görls,
• Kilian Rolf Anton Schneider,
• Mathias Micheel,
• Michael Pröhl,
• Michael Gottschaldt,
• Benjamin Dietzek and
• Wolfgang Weigand

Beilstein J. Org. Chem. 2017, 13, 2264–2272, doi:10.3762/bjoc.13.223

• the molecule [9]. Although a range of papers reports the synthesis of BF2 complexes of β-diketones such as curcuminoids [13][14] or dibenzoylmethanes [15][16], to our knowledge the reported procedures for the hydrolysis of these complexes are very limited and not always reproducible. As part of our

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• , optimum reaction conditions were extended to other 1,3-diketones 2a–e with different substitution patterns (Table 2). High yields of desired 1,2,3-triazoles were obtained using β-diketones 2a, 2b and 2c bearing methyl, ethyl and phenyl substituents (Table 2, entries 1–3). However, we observed that the

Isoxazole derivatives as new nitric oxide elicitors in plants

• Anca Oancea,
• Emilian Georgescu,
• Florentina Georgescu,
• Alina Nicolescu,
• Elena Iulia Oprita,
• Catalina Tudora,
• Lucian Vladulescu,
• Marius-Constantin Vladulescu,
• Florin Oancea and
• Calin Deleanu

Beilstein J. Org. Chem. 2017, 13, 659–664, doi:10.3762/bjoc.13.65

• synthetic approaches towards the isoxazole core include the reactions of hydroxylamine with aryl-β-diketones [20], α,β-unsaturated carbonyl compounds [21], or α,β-unsaturated nitriles [22], and 1,3-dipolar cycloaddition reactions between alkenes or alkynes and nitrile oxides [23][24][25]. Nitrile oxides are

Et₃B-mediated and palladium-catalyzed direct allylation of β-dicarbonyl compounds with Morita–Baylis–Hillman alcohols

• Ahlem Abidi,
• Yosra Oueslati and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2402–2409, doi:10.3762/bjoc.12.234

• acidity is relatively higher, led to a mixture of the mono- and bis-alkylation products 3c and 4c in 45 and 23% yields, respectively (Table 2, entries 1–3). Under the same conditions, the allylation of a variety of β-keto esters and β-diketones (Table 2, entries 4–9), in DMF at 80 °C, selectively gave the

• selected the acyclic alcohol 1b to react with stabilized carbanions derived from the β-keto esters 2e–f and β-diketones 2g–i in anhydrous THF using 1 equiv of NaH and 2 equiv of Et3B. Under these conditions, all these reactions worked well in refluxing THF, affording in 2 h the corresponding monoallylation

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

• carbonyl compounds such as β-diketones, β-keto thioesters, acetoacetamides and nitroacetone have been shown to participate in the classical Biginelli reaction [25], β-ketophosphonates 6 were found to be unreactive in similar conditions [26]. However, Yuan et al. developed a modified Biginelli condensation

Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions

• José M. Andrés,
• Miriam Ceballos,
• Alicia Maestro,
• Isabel Sanz and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2016, 12, 628–635, doi:10.3762/bjoc.12.61

• to β-nitrostyrene. Addition of malonates and β-diketones to nitrostyrenes catalyzed by IV and V. Reaction of nitrostyrenes with β-substituted cycloalkanones catalyzed by V. Reactions of nitrostyrenes with α-nitrocyclohexanone and ethyl α-nitropropionate. Supporting Information Supporting Information

• enantiomeric excess was determined by chiral-phase HPLC analysis using mixtures of hexane/isopropanol as eluent. Parent and supported bifunctional thioureas used in this work. Reaction of nitrostyrene with diethyl malonate and 2-ethoxycarbonyl cyclopentanone. Reaction of nitrostyrenes with malonates and β

• -diketones. Reaction of nitrostyrenes with β-keto esters and β-dicarbonyl compounds. Reaction of nitrostyrenes with α-nitrocyclohexanone and ethyl α-nitropropionate. Screening of catalysts and optimization of the reaction conditions for the additions of diethyl malonate and ethyl 2-oxocyclopentanecarboxylate

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• the starting substrates A simple retrosynthesis of enaminones 3 leads to the corresponding β-diketones 4 accessible through Claisen condensation of 3-phenylpropionic ester 5 with the appropriate acetophenone 6 (Scheme 3). The synthesis of ester 5 was accomplished according to Scheme 4. The classic

• byproducts. A better and less time-consuming route to 10 consists of the reaction of 2-halobenzaldehyde 7 with Meldrum´s acid in the presence of HCOOH/Et3N system with a total yield of 61–67% (step f in Scheme 4). The last step for both methods was the esterification of acids 10a,b (step e in Scheme 4). β

• -Diketones 4 were obtained using tert-butoxide or tert-pentoxide mediated Claisen condensation of esters 5 with the appropriate acetophenones 6a–d (Scheme 5, step c). The substitution pattern on compounds 6 was chosen so that the final products 1 are the precursors for the synthesis of galipinine, galipeine

(CF₃CO)₂O/CF₃SO₃H-mediated synthesis of 1,3-diketones from carboxylic acids and aromatic ketones

• JungKeun Kim,
• Elvira Shokova,
• Victor Tafeenko and
• Vladimir Kovalev

Beilstein J. Org. Chem. 2014, 10, 2270–2278, doi:10.3762/bjoc.10.236

• synthesis of β-diketones from acids and ketones with an immediate activation of both carbonyl and methylene components in the course of the reaction. Herein, we would like to describe a direct and operationally simple TFAA/TfOH-mediated synthesis of 1,3-diketones from unmodified carboxylic acids and ketones

• (indanones, tetralone, acetophenones, 2-acetylthiophene and methyl benzyl ketone) with alkanoic acids RCOOH 1d–h (where R = 1-adamantylmethyl, neopentyl, isopropyl, methyl, phenyl) gave the corresponding β-diketones 3c–t in 37–86% yields (Table 2). In most cases reactions were carried out at the molar ratios

• ]. The obtained diketones were mainly present in the enol form in CDCl3 solution. The enol structures of the β-diketones 3 were supported by 1H/13C NMR spectra, which showed a set of singlets at δ 5.9–6.2 corresponding to the α-olefinic protons for 3l–3r, 3s and 3w, signals at δ 106.5–116.1 and at δ 96.1

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• several substituents and enolates 33 can be generated from methyl- or ethyl vinyl ketone, the corresponding α,β-unsaturated esters being unreactive. Enamines 34 arise from cyclic or linear C3–C5 ketones, acetophenones and β-diketones. It is noteworthy, that the reactions are highly regiospecific for

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

Efficient synthesis of dihydropyrimidinones via a three-component Biginelli-type reaction of urea, alkylaldehyde and arylaldehyde

• Haijun Qu,
• Xuejian Li,
• Fan Mo and
• Xufeng Lin

Beilstein J. Org. Chem. 2013, 9, 2846–2851, doi:10.3762/bjoc.9.320

• chemistry [5][6][7][8]. Recently, many one-pot variants of Biginelli-type reactions for the preparation of novel DHPMs using various active methylene compounds [9][10][11][12][13][14][15], such as enaminone, cyclic β-diketones, acetophenone, benzocyclic ketones and β-oxodithioesters etc., have also been

Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

• Brian M. Casey,
• Dhandapani V. Sadasivam and
• Robert A. Flowers II

Beilstein J. Org. Chem. 2013, 9, 1472–1479, doi:10.3762/bjoc.9.167

• 73% yield. To examine the breadth of this method, a series of δ-aryl-β-dicarbonyl substrates was prepared by a previously reported procedure [17]. As shown in Table 1, the intramolecular cyclization of δ-aryl-β-diketones with unsubstituted aryl rings (Table 1, entries 1 and 3) afforded 2-tetralone

• oxidation of several β-diketones and their related silyl enol ethers by CAN and the more lipophilic ceric tetra-n-butylammonium nitrate (CTAN) were measured in MeOH, MeCN and CH2Cl2 by using stopped-flow spectrophotometry [16]. In these experiments, initial oxidation of substrates generated radical cation

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