A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

• Dragana Vuk,
• Irena Škorić,
• Valentina Milašinović,
• Krešimir Molčanov and
• Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

• 54, 10000 Zagreb, Croatia NMR Centre, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia 10.3762/bjoc.16.96 Abstract In order to prepare novel polycyclic derivatives of bicyclo[3.2.1]octadiene systems fused with a thiophene ring, photochemical cyclization and aldol condensation

• were synthesized through Wittig reactions and subjected to photochemical cyclization, in terms of obtaining the new annulated structures. As part of this study, the aldol reaction of the starting 2-substituted carbaldehyde with acetone was also performed, which produced the thieno-fused benzobicyclo

Functionalization of 4-bromobenzo[c][2,7]naphthyridine via regioselective direct ring metalation. A novel approach to analogues of pyridoacridine alkaloids

• Benedikt C. Melzer,
• Alois Plodek and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222

• synthesis via an Heck-type palladium-catalysed reaction according to the method of Harayama [30] (Pd(II)acetate/tri(o-tolyl)phosphine/K2CO3) did not lead to the expected alkaloid 3. Also the radical procedure published by Markgraf et al. [31] using AIBN and Bu3SnH and a photochemical cyclization protocol we

Synthesis of acremines A, B and F and studies on the bisacremines

• Nils Winter and
• Dirk Trauner

Beilstein J. Org. Chem. 2019, 15, 2271–2276, doi:10.3762/bjoc.15.219

• intramolecular cyclization of 23. Attempted photochemical cyclization of 25. Representative screening conditions for the biomimetic cascade. Supporting Information Experimental procedures, spectroscopic data and copies of NMR spectra (PDF) as well as crystallographic data of compounds 16 and 17. CIF files for

Click chemistry towards thermally reversible photochromic 4,5-bisthiazolyl-1,2,3-triazoles

• Chenxia Zhang,
• Kaori Morinaka,
• Mahmut Kose,
• Takashi Ubukata and
• Yasushi Yokoyama

Beilstein J. Org. Chem. 2019, 15, 2161–2169, doi:10.3762/bjoc.15.213

• their open-form structures. Thermal back reactions As expected, all closed forms of triazoles showed thermal back reactions since the photochemical cyclization results in the loss of the aromatic stabilization energy [41] of the three contiguous aromatic rings. The changes in the absorption spectra of

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• to 1-indanones 103 has been proposed by Wessig et al. [57]. The authors have used a photochemical cyclization of ketones 100 containing good leaving groups X adjacent to the carbonyl group. As a result of irradiation, 1,4-diradicals 101 have been formed from ketones 100 through n–π* excitation

Synthesis of 2,1-benzisoxazole-3(1H)-ones by base-mediated photochemical N–O bond-forming cyclization of 2-azidobenzoic acids

• Daria Yu. Dzhons and
• Andrei V. Budruev

Beilstein J. Org. Chem. 2016, 12, 874–881, doi:10.3762/bjoc.12.86

• Daria Yu. Dzhons Andrei V. Budruev Chemistry Department, Lobachevsky State University of Nizhny Novgorod, Gagarina pr. 23, Building 5, 603950, Nizhny Novgorod, Russian Federation 10.3762/bjoc.12.86 Abstract The base-mediated photochemical cyclization of 2-azidobenzoic acids with the formation of

• -benzisoxazolones; 1,5-electrocyclization; nitrenes; photochemical cyclization; Introduction Substituted 2,1-benzisoxazoles display diverse biological activity [1][2][3][4][5][6] (Figure 1) and are widely used as starting materials for the synthesis of important heterocyclic pharmacophores, such as acridines [7][8

• nitro compounds [17][18][19][20][21], two other routes are available: the annulation of nitroso compounds [22][23] and the thermal [24], catalytic [25][26][27] or photochemical cyclization of aryl azides [28][29][30][31]. However, the presence of electron-withdrawing substituents in the 3-, 5- and 7

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• [22]. Starting from the similar isonitrile structure, 6-aroylated phenanthridines via base promoted homolytic aromatic substitution (BHAS) can be prepared [23]. Several photoinduced synthetic procedures were also applied. For instance, the photochemical cyclization of N-benzylanilines was used for

Simple synthesis of pyrrolo[3,2-e]indole-1-carbonitriles

• Adam Trawczyński,
• Robert Bujok,
• Zbigniew Wróbel and
• Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2013, 9, 934–941, doi:10.3762/bjoc.9.107

• cyanoborohydride [4]. On the other hand there are many methods of synthesis of pyrrolo[3,2-e]indoles such as the copper-catalyzed transformation of tetrahydroquinoline derivatives [4], photochemical cyclization of 1,2-bis(2-pyrrolo)ethylenes [5], the Fischer indole synthesis from indol-5-ylhydrazones [3], or a

Photosonochemical catalytic ring opening of α-epoxyketones

• Hamid R. Memarian and
• Ali Saffar-Teluri

Beilstein J. Org. Chem. 2007, 3, No. 2, doi:10.1186/1860-5397-3-2

• . [7][8][9][10][11][12][13][14][15][16][17] It is well known that the substituted pyridinium cations are good electron acceptors. [18] Garcia and coworkers have used N-alkyl-2,4,6-triphenylpyridinium tetrafluoroborate as photosensitizer in the photochemical cyclization of 5-methyl-4-hexenoic acid to

Trapping evidence for the thermal cyclization of di-(o-acetylphenyl)acetylene to 3,3'-dimethyl- 1,1'-biisobenzofuran

• Charles P. Casey,
• Neil A. Strotman and
• Ilia A. Guzei

Beilstein J. Org. Chem. 2005, 1, No. 18, doi:10.1186/1860-5397-1-18

• rearrangement of a 2,6-alkadien-4-yn-1,8-dialdehyde to a bifuran. Photochemical cyclization to a bifuran. Trapping of A by DMAD to form Diels-Alder adducts meso-3 and rac-3. Possible stepwise mechanism for rearrangement of 1 to A. Possible concerted mechanism for rearrangement of 1 to A. Ring closures of o-acyl