Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• -promoted three-component reaction of ammonium acetate, isatins and in situ-generated 3-isatyl-1,4-dicarbonyl compounds. The piperidine-promoted three-component reaction of ammonium acetate, isatins and the in situ-generated dimedone adducts of 3-ethoxycarbonylmethyleneoxindoles afforded mutlifunctionalized

• dispiro[indoline-3,2'-quinoline-3',3''-indoline] derivatives in good yields and with high diastereoselectivity. On the other hand, a similar reaction of the dimedone adducts of 3-phenacylideneoxindoles afforded unique dispiro[indoline-3,2'-pyrrole-3',3''-indoline] derivatives with a cyclohexanedione

• substituent. A plausible reaction mechanism is proposed to explain the formation of the different spirooxindoles. Keywords: cascade reaction; dimedone; isatin; 3-methyleneoxindole; multicomponent reaction; spirooxindole; Introduction Spirooxindole is one important privileged structural skeleton and is found

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• ]quinoxalinoporphyrins in good yields via a sequential reaction of copper(II) 2,3-diamino-5,10,15,20-tetraarylporphyrins, 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes, and dimedone in the presence of a catalytic amount of trichloroacetic acid in chloroform at 65 °C. Further, the newly prepared copper(II

• aldehydes and dimedone in chloroform at 65 °C. The optical properties of the newly prepared porphyrins have been investigated by using UV–vis and emission spectroscopy and the results are presented in this paper. Results and Discussion Synthesis The required precursors, copper(II) 2,3-diamino-5,10,15,20

• ]chromeno[2,3-h]quinoxalinoporphyrins 3–8. For the optimization of the reaction conditions, a model four-component reaction of copper(II) 2,3-diamino-5,10,15,20-tetra(p-tolyl)porphyrin with 2-hydroxynaphthalene-1,4-dione (2), benzaldehyde and dimedone was carried out in the presence of 20 mol % p

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• potentials of 0.075 e and 0.048 e. The cyclic dimedone-derived ylide I-12 showed similar potentials of 0.080 e and 0.052 e, as did the Meldrum’s acid-derived ylide I-13 (0.085 e and 0.057 e). Whether the ylide was cyclic or acyclic, the σ-hole opposite the β-dicarbonyl motif was consistently greater in

• cyclopropane 22a. Interestingly, Hadjiarapoglou also revisited their investigation of iodonium ylide cycloadditions and their associated mechanisms [120], using diphenylketene as a new reaction partner with dimedone iodonium ylide 6 (analogous to earlier work reported by Koser in 1975 [9]). Investigations by

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

• Koustav Singha,
• Imran Habib and
• Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

• imidazole 1-oxides. The selected CH-acids to study the scope of substrates were barbituric acid, dimedone, 4-hydroxy-6-methyl-2H-pyran-2-one, 1,3-dimethylbarbituric acid, 4-hydroxycoumarin, and 1,3-indandione. The nature of the CH-acids and 2-unsubstituted imidazole N-oxides did not affect the yield of

• work, just akin to previously mentioned methodology in Scheme 7, a wide range of imidazole N-oxides and CH-acids like dimedone, barbituric acid, Meldrum’s acid, 4-hydroxycoumarin, hydroxy-6-methylpyranone, and 4-hydroxy-7,7-dimethyl-7,8-dihydro-2H-chromene-2,5(6H)-dione were chosen along with

• -oxide 32 (2 mmol), aldehyde 33 (2 mmol) and CH acid 34 (2 mmol, barbituric acid) was refluxed in H2O (2 mL) and MeCN (5 mL) solvent mixture for 8 h. bThe mixture of imidazole N-oxide 32 (2 mmol), CH-acid 34 (2 mmol, dimedone, 4-hydroxy-6-methyl-2H-pyran-2-one, 1,3-dimethylbarbituric acid, 4

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• acid (4) as catalyst [30]. Based on this pioneer work, our research group described an efficient, highly stereoselective, one-pot process comprising an organocatalytic conjugate addition of dimedone or 4-hydroxycoumarin 1 to α,β-unsaturated aldehydes 2 followed by an intramolecular isocyanide-based

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• esters 29, such as 1,3-diketones, β-ketoesters, cyclic 1,3-diketone (dimedone), and β-ketoamide, respectively, to afford desired 1,4,5-trisubstituted 1,2,3-triazoles containing glycosyl with high yield. It should be pointed out that no byproducts were recognized under optimized reaction conditions. In

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

• ). Abonia and co-workers [85] established a catalyst-free construction of quinoline-based pyridopyridines 97 by employing a microwave-assisted three-component reaction of 3-formyl-2-oxoquinoline derivatives 95, 2,4,6-triaminopyrimidine (96) and a cyclic 1,3-diketone such as dimedone (6a) in DMF. The

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• (55%) yield. Unfortunately, the reaction was not successful with dimedone (2d), 1,3-indanedione (2e) and acyclic 1,3-dicarbonyl compounds such as acetylacetone (2e) and ethyl acetoacetate (2f). The structure and regiochemistry of all the products were confirmed by detailed analysis of their spectral

• data (IR, 1H, 13C and Mass) which were further unambiguously established by single crystal X-ray analysis of a representative compound 3e (Scheme 2 and Supporting Information File 3). Although triazole 1a reacted with cyclohexanedione 2a (vide supra), its reaction with dimedone 2d provided a complex

• the scope of cyclohexane-1,3-dione 2a is limited. On the contrary, dimedone (2d) did not react with N-tosyl-1,2,3-triazole, but reacted with N-mesyl-1,2,3-triazole to form the 5,5-dimethyl-3-oxo-cyclohex-1-en-1-yl methanesulfonate intermediate 4a. The highly substrate-dependent nature of the reaction

1,2,3-Triazoles as leaving groups: S_NAr reactions of 2,6-bistriazolylpurines with O- and C-nucleophiles

• Dace Cīrule,
• Irina Novosjolova,
• Ērika Bizdēna and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 410–419, doi:10.3762/bjoc.17.37

• transformation into a C–C bond. Compounds containing electron-withdrawing groups such as malonitrile, dimedone, ethyl cyanoacetate and diethyl malonate were used as C-nucleophiles. Transformations were performed in DMF in the presence of NaH and the products were obtained in high yields (Scheme 6). The lower

• deprotonates purine C(8)–H, thus suspending the SNAr process. The structures of C6-substituted products 5a–d were elucidated by NMR and IR analysis. These compounds can exist as either C–H acids (A) or N–H acids (B), but dimedone conjugate 5b may possess also an enol form C (Figure 1). During the structural

• purine–dimedone conjugate 5b revealed two downfield shifts of 194.1 and 185.3 ppm. It showed that the structure is not symmetrical and corresponds to either tautomer structure B or C in CDCl3 solution with a theoretical preference for enol form C. Finally, the structure of C–H tautomer 5dA was proved by

1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds

• Vito A. Fiore,
• Chiara Freisler and
• Gerhard Maas

Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253

• triphenylphosphane with alkyl propiolates [9][10] or dialkyl acetylenedicarboxylates [11] and strong CH-acids, such as Meldrum’s acid, 1,3-dimethylbarbituric acid, dimedone and indane-1,3-dione, leads to stable 1,4-diionic phosphonium betaines I or II (Scheme 1) in high yields. An analogous reaction has been

• was obtained from 1,1,1,5,5,5-hexafluoropropane-2,4-dione (pKa 2.30 in DMSO) and dimedone (pKa 11.42 in DMSO). Figure 1 also shows that 3-aryl- as well as various 3-alkyl-substituted propiolamides 1 furnish betaines 3 in high yields. A separate case was observed for 3-trimethylsilylpropiolamide 1f

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• the 4,5-dihydropyrrolo derivatives, we were interested to synthesize fully aromatic products by using C5–H containing cyclohexane-1,3-dione derivatives in place of dimedone. Thus, using cyclohexane-1,3-dione (5) or 5-phenylcyclohexane-1,3-dione (6) allowed the isolation of novel substituted pyrrolo

• nanoreactor which is a single molecule as catalyst in the earliest steps of the mechanistic pathway (Figure 6). This multicomponent reaction is expected to comprise a series of condensations and subsequent ring-closure cascade reactions (Scheme 3). To demonstrate the mechanistic pathway, dimedone (2), isatin

• (1a) and p-toluidine (3a) were selected as model substrates. Firstly, dimedone and p-toluidine form enaminoketone A through a condensation reaction and BATA-MC provides the environment for this condensation in water. To investigate this primary step, a control experiment was performed. One aliquot was

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• -component cyclization of 2-formylbenzoic acids, primary amines and a 1,3-dicarbonyl compounds. The first proposal uses 2-formylbenzoic acid 33 (R = H, conditions A, Scheme 9), cyclic aliphatic and aromatic diketones 34 such as dimedone (R2R3 = -CH2CMe2CH2-) as the 1,3-dicarbonyl partner and a variety of

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• -free or water medium with good to excellent yields (Scheme 3) [40]. Some results for these catalytic systems were summarized. The reaction between dimedone (20), aldehydes 7, and ammonium chloride (21) produced excellent yields of 1,8-dioxodecahydroacridine derivatives 22 within 10–15 minutes at 80–100

• catalytic system was also studied by the reaction of isatin, malononitrile, and dimedone. After completion of the reaction, the reaction mixture was filtered and the same substrates were added directly to the filtrate solution containing the homogeneous catalytic system. There is no need to add solvent as

• , catalyst 53 was utilized for the synthesis of 2H-indazolo[2,1-b]phthalazine-1,6,11(13H)-trione derivatives 55 via a one-pot, three-component reaction of phthalhydrazide (54), aldehydes 7, and dimedone (20) or cyclohexane-1,3-dione (for R3 = H, 20) under solvent-free conditions (Scheme 9). To check the

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• catalytic asymmetric construction of the cyclic enaminone-based 3-substituted 3-amino-2-oxindole scaffold with potential bioactivity on the basis of enantioselective additions of cyclic enaminones to N-Boc-isatin imines [40]. As shown in Scheme 7, the addition of dimedone-derived enaminones 22 to a variety

• %) and good to high enantioselectivities (84–96% ee). The process was compatible with a wide range of N-Boc-isatin imines bearing various substituents, the electronic nature and position of which having no obvious effect on the enantioselectivity. Moreover, a variety of dimedone-derived enaminones

• aldehydes catalyzed by L-diphenylprolinol trimethylsilyl ether. Addition of dimedone-derived enaminones to N-Boc-isatin imines catalyzed by a phosphoric acid. Addition of hydroxyfuran-2-one-derived enaminones to N-Boc-isatin imines catalyzed by a phosphoric acid. Zinc-catalyzed Mannich reaction of N-Boc

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

• . 1,3-Cyclohexanedione and dimedone gave adducts 8 and 9, respectively (Table 1, entries 3 and 4) which exist predominantly in the enolic form. In favor of this assertion, in proton NMR spectra of 8 and 9 broad singlets at 2.33 and 2.23 ppm were observed (Table 2), corresponding to methylene groups. At

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

• ] (Scheme 16). These reactions were performed using both acyclic and cyclic ketones. In the case of dimedone, the reaction was carried out in ethanol at room temperature overnight [54]. Remarkably, N,N-dialkylanilines in DMF solution at 50–60 °C also react with E-1a as Michael donors to give diethyl 2-(4

• ethyl acetate at room temperature, led to a mixture of pyrazolone 87 and pyridazine 88 in favor of the former compound (54%) [71] (Scheme 27). Heating equimolar amounts of E-1a and dimedone (89) in ethanol at reflux for 8 h afforded 4H-pyran 90 as the heterocyclization product of the initially formed

Solvent-free sonochemistry: Sonochemical organic synthesis in the absence of a liquid medium

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 1850–1856, doi:10.3762/bjoc.13.179

• ninhydrin and dimedone. Both systems were investigated in the complete absence of solvent and without the presence of any grinding media (such as inert silica beads) to help mediate the reaction. The aldol reaction was successfully carried out by twin screw extrusion, as I have reported previously [6]. The

• ultrasonic irradiation at room temperature that is instigating and accelerating this chemical reaction. Further confirmation that sonochemistry is a viable method to carry out solid state organic synthesis was obtained by carrying out an aldol reaction between ninhydrin and dimedone (Scheme 2). The optimised

• indicating that a complete reaction had taken place between a hydroxy group of ninhydrin and the activated methylene of dimedone (Figure 7). This reaction has previously been carried out by twin screw extrusion in the absence of solvent [6], and it was confirmed that the same product was obtained by both

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

• not isolable and spontaneously recyclized to dihydropyridinylphosphonate 150 (Scheme 32) [46]. In this way, the reaction of 6-methyl-3-formylchromone (75) with cyclic 1,3-dicarbonyl compounds such as dimedone (151), 1-phenylpyrazolidine-3,5-dione (153) or barbituric acid (155) afforded the fused

Strecker degradation of amino acids promoted by a camphor-derived sulfonamide

• M. Fernanda N. N. Carvalho,
• M. João Ferreira,
• Ana S. O. Knittel,
• Maria da Conceição Oliveira,
• João Costa Pessoa,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2016, 12, 732–744, doi:10.3762/bjoc.12.73

• is an obvious candidate as catalyst. Indeed, water inclusion in reaction paths with high-lying transition states is often observed in water as solvent, as in biochemical reactions, and was demonstrated for, e.g., the analytical detection of sulfenic acids with dimedone [36]. In these systems water

Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts

• Mostafa Kiamehr,
• Firouz Matloubi Moghaddam,
• Satenik Mkrtchyan,
• Volodymyr Semeniuchenko,
• Linda Supe,
• Alexander Villinger,
• Peter Langer and
• Viktor O. Iaroshenko

Beilstein J. Org. Chem. 2013, 9, 1119–1126, doi:10.3762/bjoc.9.124

• -mentioned study we discovered an interesting reaction that represents an external dinucleophilic addition of the dimedone molecule to the pyridinium salt 2a, taken as a random example, delivering 8-oxa-10-aza-tricyclo[7.3.1.02,7]trideca-2(7),11-diene (3a) in modest yield (Scheme 1). Previously, we have

• pyridinium salts and diketones. Herein we report the results of that study. First, we studied the reaction of pyridinium salt 2a with dimedone (1a) using various bases in different solvents (Table 1). At the same time, different ratios of 1a and 2a were examined. To reach the optimal yields, dimedone and

• included implicitly within the IEFPCM method (more details on inclusion of the solvent can be found in Supporting Information File 2). For simplicity 1,3-cyclohexanedione rather than dimedone was included in the computations. Our ability to calculate the mechanism as well as to make any further predictions

Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

• Yan Sun,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 8–14, doi:10.3762/bjoc.9.2

• three-component reaction of arylamine, isatin and cyclopentane-1,3-dione. Results and Discussion Recently we found that the four-component reactions of arylamine, acetylenedicarboxylate, isatin and dimedone in acetic acid resulted in the novel functionalized tetrahydrospiro[indoline-3,2’-quinoline

• of spiro[dihydropyridine-oxindole] 1b. The two kinds of spiro compounds from reactions of isatins with arylamines and cyclic 1,3-diketones. Molecular structure of spiro[dihydropyridine-oxindole] 2f. Molecular structure of compound 3d. The four-component reactions containing dimedone (a) and

Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives

• Ishmael B. Masesane and
• Zelalem Yibralign Desta

Beilstein J. Org. Chem. 2012, 8, 2166–2175, doi:10.3762/bjoc.8.244

• of salicylaldehyde (5) with dimedone (18) in the presence of a catalytic amount of KF/Al2O3 (Scheme 6) [21]. The reaction is thought to proceed through a Knoevenagel condensation, a Michael addition and an intramolecular cyclization. The reaction was repeated with chloro-, bromo-, dichloro-, dibromo

Regioselectivity in the multicomponent reaction of 5-aminopyrazoles, cyclic 1,3-diketones and dimethylformamide dimethylacetal under controlled microwave heating

• Kamal Usef Sadek,
• Ramadan Ahmed Mekheimer,
• Tahany Mahmoud Mohamed,
• Moustafa Sherief Moustafa and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2012, 8, 18–24, doi:10.3762/bjoc.8.3

• (DMFDMA) in DMF at 150 °C under controlled microwave heating afforded regioselectively 8,9-dihydropyrazolo[1,5-a]quinazolin-6(7H)-ones 6 rather than the corresponding dihydropyrazolo[5,1-b]quinazolin-8(5H)-ones 4. Keywords: aminopyrazoles; dimedone; DMFDMA; regioselectivity; Introduction Several

• ., either kinetic or thermodynamic [11][12][13]. It has been reported that the use of microwave or ultrasound irradiation provides an additional parameter for synthetic selectivity [14][15][16][17]. Results and Discussion The multicomponent reaction of 5-aminopyrazoles, dimedone and aromatic aldehydes was

• triethylamine as base produces the more thermodynamically stable dihydropyridine (Hantzsch-type product). In addition, the nature of the catalyst plays an important role [20]. A one-pot three component reaction of 5-amino-1H-pyrazole-4-carbonitrile, dimedone and triethylorthoesters in toluene under reflux was

Surfactant catalyzed convenient and greener synthesis of tetrahydrobenzo[a]xanthene-11-ones at ambient temperature

• Pravin V. Shinde,
• Amol H. Kategaonkar,
• Bapurao B. Shingate and
• Murlidhar S. Shingare

Beilstein J. Org. Chem. 2011, 7, 53–58, doi:10.3762/bjoc.7.9

• our initial study, reaction of 4-chlorobenzaldehyde, β-naphthol and dimedone in water was considered as a standard model reaction (Scheme 1). During this investigation, efforts were mainly focused on a variety of surfactants. In this regard, different cationic surfactants such as

• methide (o-QM), subsequent Michael addition of dimedone to the o-QM followed by attack of the phenolic –OH group of the o-QM at the carbonyl carbon of dimedone to yield a cyclic hemiketal that on dehydration affords the final product. To generalize the synthetic procedure, various electronically divergent

• aryl aldehydes were treated with β-naphthol and dimedone under the optimized reaction conditions and all these substrates were found to be equally amenable to these conditions. Interestingly, some heteroaryl aldehydes also underwent the reaction smoothly. Representative results are summarized in Table