Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• hours of reaction. A one-pot method for the synthesis of 1,3-dimethylimidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazine 3a was exemplified by successive reactions of imidazo[4,5-e][1,2,4]triazine 7 with diethyl acetylenedicarboxylate and excess KOH. Acidification of aqueous solutions of potassium salts

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

• Xiu-Yu Chen,
• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• ]naphthyridine and 2-azabicyclo[4.2.0]octa-3,7-diene derivatives. Results and Discussion Initially, the reaction conditions were briefly examined by using isoquinoline (1), dimethyl acetylenedicarboxylate (DMAD, 2) and 5,6-unsubstituted 1,4-dihydropyridine 3 as standard reaction (Table 1). The three-component

• acetylenedicarboxylate and 5,6-unsubstituted 1,4-dihydropyridines with N–Ar groups did not give the above isoquinolino[1,2-f][1,6]naphthyridines, but the unique 2-azabicyclo[4.2.0]octa-3,7-diene-7,8-dicarboxylates were isolated in moderate yields. These products were obviously produced from the formal [2 + 2

• ] cycloaddition between dimethyl acetylenedicarboxylate and the 5,6-unsubstituted 1,4-dihydropyridine. Therefore, the reactions of dimethyl acetylenedicarboxylate and 5,6-unsubstituted 1,4-dihydropyridines were carefully explored. After adjusting the reaction conditions, we were pleased to find that 2-azabicyclo

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

• Ekaterina A. Lystsova,
• Maksim V. Dmitriev,
• Andrey N. Maslivets and
• Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

• ] and reactions of 3-acyl-2,3-dihydro-1,3-benzothiazole-2-carbonitriles with acetylenedicarboxylate (Scheme 1, entry 9) [4]. The second group of approaches to the PBTA scaffold is an annulation of o-aminothiophenol with a pyrrolothiazole moiety (Scheme 2). It includes catalytic cascade reactions of o

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• dialkyl acetylenedicarboxylate or sodium diethyl oxalacetate [28][29][30][31][32][33][34]. The resulting products have the 4-position locked by the alkoxycarbonyl (–COOR) group and these 2-pyrrolidinone derivatives can be functionalized with amines as nucleophiles via the 3-position [10][35][36][37][38

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• )amino)-substituted maleimide derivatives 4b–e (Table 1). Naka et al. previously reported the facile syntheses of N-alkyl-arylaminomaleimide derivatives as D–A system molecules by the reaction of dimethyl acetylenedicarboxylate with arylamines, which showed AIEE properties in 10% or 20% (v/v) THF aqueous

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

• Soumyadip Basu,
• Sauvik Chatterjee,
• Suman Ray,
• Suvendu Maity,
• Prasanta Ghosh,
• Asim Bhaumik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

• % purity), and trans-4-methoxycinnamaldehyde (98+% purity) from Alfa Aesar were used. Dimethyl acetylenedicarboxylate (99% purity) and diethyl acetylenedicarboxylate (95% purity) were bought from Sigma-Aldrich. p-Toluidine (99% purity for synthesis), p-anisidine (99% purity for synthesis), 2,4

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

• prepared by Ru-catalyzed [3 + 2]-cycloaddition of ynoate esters 170 with azide to produce metal-bound heterocyclic complexes 171 via an intramolecular cycloaddition reaction. The ynoate esters including diethyl acetylenedicarboxylate, ethyl 4,4,4-trifluoro-2-butynoate, methyl phenylpropiolate, and ethyl 2

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Synthesis of functionalized imidazo[4,5-e]thiazolo[3,2-b]triazines by condensation of imidazo[4,5-e]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5-e]thiazolo[2,3-c]triazines

• Alexei N. Izmest’ev,
• Dmitry B. Vinogradov,
• Natalya G. Kolotyrkina,
• Angelina N. Kravchenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2021, 17, 1141–1148, doi:10.3762/bjoc.17.87

• with asymmetric substrates is the high regioselectivity of the cyclizations of intermediate Michael adducts at one of several reactive nitrogen atoms. For example, reported by Giannola et al. [21], the reaction of 3-thioxo-1,2,4-triazin-5-ones 1 with dimethyl acetylenedicarboxylate (DMAD) leads to the

• (Table 1, entries 9–14). The corresponding isomeric imidazo[4,5-e]thiazolo[2,3-c]triazines 5 were formed in trace amounts and were detected only in the 1H NMR spectra of the evaporated reaction mixtures. The reactions of bicyclic structures 3a–g with dimethyl acetylenedicarboxylate proceeded with similar

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• ) and diethyl acetylenedicarboxylate (3a) was performed to construct the seven-membered indole ring system with the aid of the LS-FAS-Cu catalyst, and the results are summarized in Table 1. At the beginning, the three-component reaction was conducted without the presence of any catalyst, but no products

• the products 4j–m were obtained in good to excellent yields. The acid-labile cyclopropanecarboxaldehyde (2n) could also participate well, and the product 4n was obtained in 77% yield without damage of the cyclopropane structure. Dimethyl acetylenedicarboxylate (3b), 1a and 2a could tolerate the LS-FAS

• reaction of 4-aminoindole (1a), 4-methylbenzaldehyde (2a) and diethyl acetylenedicarboxylate (3a). In order to confirm the heterogeneity of this reaction, we investigated the Cu leaching during the reaction process. The reaction mixture (including the catalyst) was allowed to stir for a period of time

Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• work [9] and found that the correct structure of the studied compound was structure B (CCDC 2019497) (Scheme 1). In fact, for now, four approaches to BTAs III are known [21][22][23][24][25] (Scheme 2). They include the reaction of dimethyl acetylenedicarboxylate (DMAD) with o-aminothiophenol (1a) on

An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• dependent mostly on its substituents (e.g., EWG or EDG) relative to the other reactants [6][42][45][67][103][153][230]. Maleimides (including maleic anhydride) [55][71][92][96][150][176][177][179][180][181][182][183][184][186][192][229][231], dimethyl acetylenedicarboxylate (DMAD) and p-benzoquinone [60

• (i) maleimide derivatives, (ii) dimethyl acetylenedicarboxylate (DMAD) and (iii) p-benzoquinones. Generic schemes showing pentafulvenes participating as dienophiles in Diels–Alder cycloadditions with (i) o-benzoquinones and (ii) polyhalogenated cyclopentadienes. Reaction of 8,8-dicyanoheptafulvene

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Domino ring-opening–ring-closing enyne metathesis vs enyne metathesis of norbornene derivatives with alkynyl side chains. Construction of condensed polycarbocycles

• Ritabrata Datta and
• Subrata Ghosh

Beilstein J. Org. Chem. 2018, 14, 2708–2714, doi:10.3762/bjoc.14.248

• situ with dimethyl acetylenedicarboxylate (DMAD). In case the Diels–Alder reaction would take place through the triene 9a the tetracyclic structure 12a would be formed. However, 13C NMR spectra of the product revealed the presence of eight methylene carbon signals at δ 28.6, 28.9, 30.9, 33.5, 36.7

• mixture of the diene 11 (40 mg, 0.11 mmol) and dimethyl acetylenedicarboxylate (0.02 mL, 0.16 mmol) in toluene (5 mL) was heated at 65 °C for 2 h. The solvent was removed under reduced pressure and was purified by column chromatography (12% EA/PE) to afford the Diels–Alder adduct 14 (42 mg, 76%) as an oil

• acetylenedicarboxylate (0.04 mL, 0.27 mmol) was added to the reaction mixture. The reaction mixture was then heated for 12 h till the Diels–Alder reaction of the diene 9b generated in situ was complete. The solvent was removed under vacuo and the product was purified by column chromatography (15% EA/PE) to afford the

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• with G-I catalyst 1 under ethylene, which resulted in the formation of the dienes 97a (63%) and 97b (83%, Scheme 15). Further, treatment of dienes 97a,b with dimethyl acetylenedicarboxylate (DMAD, 98) separately delivered the corresponding cycloadducts. Subsequently, aromatization was achieved by using

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• of substituted 1,3,4-tri- or 1,3,4,5-tetrasubstituted pyrazoles [1][2][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] or indazoles. Dimethyl acetylenedicarboxylate (DMAD, R3 = COOMe) or its analogues (diethyl; R3

• vessels is inconvenient and may be even dangerous. Two strategies can overcome such problems: liquid DMAD, diethyl acetylenedicarboxylate or alkyl propiolate can be used instead of acetylene and the resulting pyrazole-3,4-dicarboxylates or pyrazole-3-/4-carboxylates can then undergo hydrolysis and

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• metal-free method for the synthesis of benzothiophenes via a photocatalyzed tandem addition/cyclization reaction (Scheme 11) [41]. Aryl thiols were coupled with dimethyl acetylenedicarboxylate, applying 9-mesityl-10-methylacridinium perchlorate (Acr+-Mes ClO4−) as organic photocatalyst and benzoic acid

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

• synthesis of many naturally occurring compounds which exhibit biological and pharmaceutical activity [61]. A typical example of the generation of resonance-stabilized phosphorus ylides 65 comprises triphenylphosphine, dialkyl acetylenedicarboxylate, and arylsulfonic hydrazides providing the corresponding

• ylides in high yields of 90 to 95% as two rotational isomers 65’ and 65’’ (Scheme 42). The intermediate product, formed by the addition of triphenylphosphine to dialkyl acetylenedicarboxylate, is protonated here by arylsulfonic hydrazide as an NH-acid. The deprotonated form of the NH-acid as a nitrogen

• -(arylsulfonylhydrazono)butanoates 74 as the CH-acids [27]. Diastereoselectivity of the reaction was found in the latter case (Scheme 47) [27]. The generation of two isomers of phosphorus ylides was carried out via the addition of triphenylphosphine to DAAD (dialkyl acetylenedicarboxylate), followed by protonation of the

Preparation and isolation of isobenzofuran

• Morten K. Peters and
• Rainer Herges

Beilstein J. Org. Chem. 2017, 13, 2659–2662, doi:10.3762/bjoc.13.263

• ): Dimethyl acetylenedicarboxylate (9, 1.00 g, 7.04 mmol) was dissolved in benzene (25 mL) under a nitrogen atmosphere. A freshly prepared solution of isobenzofuran (1), which was prepared from DMIBF (7, 1.10 mmol, 165 mg), prior to purification by chromatography (see procedure above) was added dropwise and

New approach toward the synthesis of deuterated pyrazolo[1,5-a]pyridines and 1,2,4-triazolo[1,5-a]pyridines

• Aleksey Yu. Vorob’ev,
• Vyacheslav I. Supranovich,
• Gennady I. Borodkin and
• Vyacheslav G. Shubin

Beilstein J. Org. Chem. 2017, 13, 800–805, doi:10.3762/bjoc.13.80

• dimethyl acetylenedicarboxylate (2a, DMAD) in MeCN D-labeled pyrazolo[1,5-a]pyridine 3 was obtained in 70% yield (Table 1). The deuteration at room temperature even for 24 h led to a significantly lower degree of deuteration (DD, 20%). Salt 1b gave the corresponding 5-CD3-7-D-pyrazolopyridine 5 along with

NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• -dimethylfuran with dimethyl acetylenedicarboxylate in toluene was studied. With this system the authors could optimize the reaction conditions in a rapid manner with the consumption of very small amounts of solvent and reagents (Figure 12c). It is interesting to note that this set-up worked with standard, non

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

• , resulting from reaction of isocyanide with dialkyl acetylenedicarboxylate, added to the carbonyl group of the acylphosphonate followed by an intramolecular cyclization. A palladium-catalyzed isocyanide-based three-component pathway into phosphorylated quinazolines has been described by Wu et al. [80]. The

• -component reaction of acylphosphonates, isocyanides and dialkyl acetylenedicarboxylate to afford 2-phosphonofuran derivatives. Synthesis of (4-imino-3,4-dihydroquinazolin-2-yl)phosphonates via an isocyanide-based three-component reaction. Silver-catalyzed three-component synthesis of (2-imidazolin-4-yl

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• acetylenedicarboxylate (DMAD, 129) to generate the tetracyclic system 130 (Scheme 27). To design synthetically challenging oxa-bowls, Kotha and Ravikumar [31] have utilized the RRM and ERRM of extended norbornene systems. The key building blocks such as 133 and 134 were prepared from a readily available DA adduct 131

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• -trimerization of two different alkynes with a high chemo- and regioselectivity. The Rh(I)/H8-BINAP complex catalyzed the partially intermolecular cyclotrimerization of 1,9-decadiyne (271) and diethyl acetylenedicarboxylate (272) to give [6]metacyclophane derivative 273 (Scheme 44) [177]. This approach is also

• applicable to synthesize various polyether-based cyclophanes. In this report, they have synthesized various polyether containing cyclophanes by a cross-cyclotrimerization catalyzed by a cationic rhodium(I)/H8-BINAP complex as a key step. The ether linked α,ω-diynes and dimethyl acetylenedicarboxylate were

• acetylenedicarboxylate (DMAD) to deliver compounds 332a,b (77%). These DA adducts were irradiated in diethyl ether/dichloromethane (5:1) to offer the corresponding bioxaquadricyclane 333, subsequent thermolysis gave the bioxepine 334 (81%). Finally, aromatization of bioxepine 334 with trifluoroacetic acid (TFA