Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• , Pushkin str. 1a, 355017 Stavropol, Russian Federation 10.3762/bjoc.20.24 Abstract The possibility of functionalization of dipyrido[3,2-e:2′,3′-h]acenaphthene containing a quino[7,8-h]quinoline fragment and being a highly basic diazine analog of 1,8-bis(dimethylamino)naphthalene (“proton sponge”) has been

• comparison, in the protonated cation of the starting diazine 5 in CD3CN, the chemical shift of the “acidic” proton is observed at 18.02 ppm [15]. Next, we evaluated the pKa value of base 14 by a competitive method in acetonitrile (NMR transprotonation involving an equivalent amount of "proton sponge" 1 as a

• reference compound) [6]. Additionally, we measured the basicity of unsubstituted compound 5 in acetonitrile for the first time by the same method and the results are given in Figure 7; the pKa values for compounds 1 and 3 are taken from references [24][25]. As can be seen, although diazine 14 turned out to

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• such as triazine, diazines or aromatics containing cyano and sulfone groups are popular acceptor units for the construction of highly efficient TADF emitters [8][9][10][11]. Pyrimidine (1,3-diazine) owing to its aromaticity, significant π-deficiency, strong electron affinity, high luminous efficiency

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• -anilinoquinazoline; anticancer agents; N-arylation; 4-chloroquinazoline; microwave irradiation; Introduction N-Heterocyclic compounds are commonly present in pharmaceuticals, bioactive natural products, agrochemicals, and synthetic drugs [1][2]. Quinazoline, a benzo-fused N-heterocyclic framework (benzo-1,3-diazine

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• coordination bonds. The coordination sphere of the Cu1 and Cu2 central ions is completed with Cl1, Cl2 and Cl3, Cl4 chloride anions, respectively. In the molecules A and B the pyridin-2-yl substituents are twisted in opposite directions relative to the mean plane of the 1,2-diazine moiety with the dihedral

• , Supporting Information File 2). Additionally, the complex 17 in a solid state is also stabilized with π–π stacking interactions between the 1,2-diazine moieties and the pyridin-2-yl substituents of the ligands (Figure S1b, Supporting Information File 2). The FTIR spectrum recorded for complex 17 confirmed

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• , TN 38112, USA Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105-3678, USA 10.3762/bjoc.16.59 Abstract Guided by computational analysis, herein we report the design, synthesis and evaluation of four novel diazine-based histone deacetylase

• inhibitors (HDACis). The targets of interest (TOI) are analogues of panobinostat, one of the most potent and versatile HDACi reported. By simply replacing the phenyl core of panobinostat with that of a diazine derivative, docking studies against HDAC2 and HDAC8 revealed that the four analogues exhibit

• lay the foundation for future design strategies toward more potent HDACis for HDAC8 isozymes and further therapeutic applications for neuroblastoma. Keywords: diazine; histone deacetylase; inhibitors; isozymes; panobinostat; Introduction One of the most important posttranslational modifications

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

• Longcheng Hong,
• Sebastian Ahles,
• Andreas H. Heindl,
• Gastelle Tiétcha,
• Andrey Petrov,
• Zhenpin Lu,
• Christian Logemann and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 618–625, doi:10.3762/bjoc.14.48

• ) reaction of 1,2-diazine as well as 1,2,4,5-tetrazine. Its stability towards air and moisture was demonstrated by NMR studies enabling its application in organic transformations without glovebox. A one-pot procedure for its synthesis was developed starting from 1,2-bis(trimethylsilyl)benzene greatly

• enhancing its practicality. Comparative reactions were carried out to evaluate its catalytic activity in IEDDA reactions of diazine including phthalazine as well as 1,2,4,5-tetrazine. Keywords: air-stable catalyst; bidentate; bisboron; diazine; Diels–Alder; Lewis acid; Introduction The development of

• 1,2-diazine as well as 1,2,4,5-tetrazine. Its stability towards air and moisture was demonstrated by NMR analysis and enables its application in organic synthesis without using a glovebox. A new one-pot procedure for its synthesis was developed starting from 1,2-bis(trimethylsilyl)benzene, which will

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• conditions allowed smooth oxidation providing the target compound in an excellent yield. For the regioisomeric diazine, (4-chlorobenzyl)pyrazine (5d), no oxidation was observed after 24 h at 100 °C. To our delight, by increasing the reaction temperature to 130 °C, (4-chlorophenyl)(pyrazin-2-yl)methanone (6d

• ) delivered the corresponding ketone 6f, albeit in a poor yield of 40%, thus supporting the metalation hypothesis. The regioisomer of diazine 5f, 3-benzyl-6-methylpyridazine (5g), could be smoothly oxidized to the corresponding ketone in 81% yield. It is worth mentioning that in 5f as well as 5g no additional

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• 1,2-diazine or imine co-reactants to yield functionalized hydrazones or benzylanilines. SCPC with tertiary amines enabled electron-deficient alkenes to be alkylated and furoquinolinones to be accessed. Primary amines on their own led to self-reactions involving C–N coupling and, with terminal diamines

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• carmegliptin as its HCl salt. 3. Pyrimidines and quinazolines Whilst pyridine rings and their partially or fully saturated derivatives are very frequent components of pharmaceutical species there are also a considerable number of compounds based on diazine and triazine ring systems. Amongst the diazines