Synthesis of novel [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines and investigation of their fungistatic activity

• Anna V. Korotina,
• Svetlana G. Tolshchina,
• Rashida I. Ishmetova,
• Natalya P. Evstigneeva,
• Natalya A. Gerasimova,
• Natalya V. Zilberberg,
• Nikolay V. Kungurov,
• Gennady L. Rusinov,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2022, 18, 243–250, doi:10.3762/bjoc.18.29

• labeling proteins and visualizing cancer due to the ability of s-tetrazine to fast and biocompatible ligation with alkenes via the inverse electron demand Diels–Alder reactions [29][30][31]. At the same time, azolo-annulated 1,2,4,5-tetrazines remain to be a scarcely studied class of compounds, mainly due

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

• Ramazan Koçak and
• Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

• reaction conditions. Inverse electron-demand Diels–Alder reactions are cycloadditions between electron-rich dienophiles and electron-poor dienes. EDGs raise the electron density of dienes and, in parallel, raise the LUMOdiene–HOMOdienophile energy gap, and consequently the reactivity decreases. Although

• . Structures of s-tetrazines 2a–l. UV–vis spectra of 3c–f and 3k in CH3CN at rt (c = 5 μM). Fluorescence spectra of 3c–f and 3k in CH3CN at rt (c = 5 μM). Ambient (top) and fluorescence (bottom, under 365 nm UV light) images of 3c–f and 3k in CH3CN. Inverse electron-demand Diels–Alder reactions of

• dibenzosuberenone (1) with tetrazines 2a–l. Inverse electron-demand Diels–Alder reactions between dibenzosuberenone 1 and tetrazines 2ka and 2lb. a5.55 mmol 1, 3.70 mmol 2k, 10 mL toluene, 120 ˚C, 48 h. b4.85 mmol 1, 0.98 mmol 2l, 100 ˚C, overnight (solvent free). Proposed reaction mechanism for the formation of

Synthetic mRNA capping

• Fabian Muttach,
• Nils Muthmann and
• Andrea Rentmeister

Beilstein J. Org. Chem. 2017, 13, 2819–2832, doi:10.3762/bjoc.13.274

• structure of Ecm1 which forms a substrate binding cleft rather than a pocket [94]. Vinylbenzyl-modified cap analogues (bearing the modification at either the N7 or N2-position) provided a platform for inverse electron-demand Diels–Alder reactions with tetrazine conjugates and for photo-click reactions using

Indenopyrans – synthesis and photoluminescence properties

• Andreea Petronela Diac,
• Ana-Maria Ţepeş,
• Albert Soran,
• Ion Grosu,
• Anamaria Terec,
• Jean Roncali and
• Elena Bogdan

Beilstein J. Org. Chem. 2016, 12, 825–834, doi:10.3762/bjoc.12.81

• dienophile component in inverse-electron demand Diels–Alder reactions, a series of new dihydroindeno[1,2-c]pyran derivatives was synthesized. Thus, the addition of freshly distilled indene as a diene component to oxadiazinones 1 as the dienophiles [29] under acidic conditions (TFA, TFAA) led to the formation

Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions

• Anne-Katrin Späte,
• Verena F. Schart,
• Julia Häfner,
• Andrea Niederwieser,
• Thomas U. Mayer and
• Valentin Wittmann

Beilstein J. Org. Chem. 2014, 10, 2235–2242, doi:10.3762/bjoc.10.232

• higher fluorescence staining of cell-surface glycoconjugates, the glucosamine derivative gave higher labeling efficiency with protein preparations containing also intracellular proteins. Keywords: bioorthogonal chemistry; carbohydrates; cyclopropenes; inverse-electron-demand Diels-Alder reactions

Synthesis of 3,4-dihydro-1,8-naphthyridin-2(1H)-ones via microwave-activated inverse electron-demand Diels–Alder reactions

• Salah Fadel,
• Youssef Hajbi,
• Mostafa Khouili,
• Said Lazar,
• Franck Suzenet and
• Gérald Guillaumet

Beilstein J. Org. Chem. 2014, 10, 282–286, doi:10.3762/bjoc.10.24

• -demand Diels–Alder reaction under microwave irradiation [22][23][24]. The use of 1,2,4-triazines in inverse electron-demand Diels–Alder reactions proved to be an efficient strategy for the construction of various heterocyclic compounds [25][26][27], such as azacarbazoles [28][29][30][31][32][33

• ynamides 2–5 [22][23][24][53] afforded triazinylpent-4-ynamides 6–9 in moderate to good yields (Scheme 3, Table 2). Intramolecular inverse electron-demand Diels–Alder reactions With the tethered triazines 6–9 in hand, we were able to study the cycloaddition reaction under microwave heating following the

• yields. The results are given in Table 5. Conclusion In this article, we report the successful application of a new synthesis strategy leading to 1-substituted 3,4-dihydro-1,8-naphthyridin-2(1H)-ones by inverse electron-demand Diels–Alder reactions under microwave activation. We also synthesized 5

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

• Zhiyuan Ma,
• Feng Ni,
• Grace H. C. Woo,
• Sie-Mun Lo,
• Philip M. Roveto,
• Scott E. Schaus and
• John K. Snyder

Beilstein J. Org. Chem. 2012, 8, 829–840, doi:10.3762/bjoc.8.93

• the library members produced in yields greater than 85%. Purification by LC–MS produced the final library. Conclusion Isatin-derived 1,2,4-triazines have proven to be excellent heteroaromatic azadienes for intramolecular inverse electron demand Diels–Alder reactions with tethered alkynyl dienophiles