Chan–Evans–Lam N1-(het)arylation and N1-alkеnylation of 4-fluoroalkylpyrimidin-2(1H)-ones

• Viktor M. Tkachuk,
• Oleh O. Lukianov,
• Mykhailo V. Vovk,
• Isabelle Gillaizeau and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2020, 16, 2304–2313, doi:10.3762/bjoc.16.191

• , heterocyclic analogues of activated ketimines (Figure 1), thus offering potential applications in the design of new heterocyclic chemotypes [21][22][23][24][25]. Compounds I are precursors of trifluoromethyl-substituted dihydropyrimidine derivatives which appear as original and potent scaffolds in medicinal

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

Ultrasonic-assisted unusual four-component synthesis of 7-azolylamino-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines

• Yana I. Sakhno,
• Maryna V. Murlykina,
• Oleksandr I. Zbruyev,
• Anton V. Kozyryev,
• Svetlana V. Shishkina,
• Dmytro Sysoiev,
• Vladimir I. Musatov,
• Sergey M. Desenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2020, 16, 281–289, doi:10.3762/bjoc.16.27

• under different conditions (ultrasonic activation and conventional heating) were unsuccessful, and only dihydropyrimidine 7 was obtained. Structure elucidation The purity and structures of the synthesized heterocycles were determined using elemental analysis, mass spectrometry, NMR spectroscopy (1D and

In water multicomponent synthesis of low-molecular-mass 4,7-dihydrotetrazolo[1,5-a]pyrimidines

• Irina G. Tkachenko,
• Sergey A. Komykhov,
• Vladimir I. Musatov,
• Svitlana V. Shishkina,
• Viktoriya V. Dyakonenko,
• Vladimir N. Shvets,
• Mikhail V. Diachkov,
• Valentyn A. Chebanov and
• Sergey M. Desenko

Beilstein J. Org. Chem. 2019, 15, 2390–2397, doi:10.3762/bjoc.15.231

• starting material and subsequent dihydropyrimidine ring formation. The first approach [6][7] represents a two-component cyclocondensation of 5-aminotetrazole (1) as binucleophilic component and bielectrophilic α,β-unsaturated carbonyl compounds 2 (Scheme 1, reaction 1). The second method [8][9][10][11][12

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• excellent yields. The proposed mechanism begins with the formation of the β-aminoketoimine by condensation of the steroid with two molecules of ammonia, followed by the reaction with arylaldehyde and intramolecular cyclization to a dihydropyrimidine skeleton, which suffers oxidation to the aromatic

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• all five chiral calix[4]arene catalysts promote the formation of the dihydropyrimidine product with different extents in terms of chemical yield and enantioselectivity. For the model reaction the best enantioselectivity (54% ee) was obtained when mono-hydroxyprolinamide-based calix[4]arene 69f was

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• depolymerization of cellulose [18] and the synthesis of dihydropyrimidine derivatives [19]. The monosodium salt of phosphonic acids were also employed as organocatalysts for Michael addition [20]. The capacity of phosphonic acids to increase the solubility of organic compounds in water was employed to develop

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• compounds 90 and 91 were obtained in excellent yields (Scheme 32) [92]. Two mechanisms were proposed for this conversion. In one the tert-butyl peroxy radicals were generated by the interaction of Cu salts with TBHP. This radical abstracts the C4 hydrogen of the dihydropyrimidine to generate P, which would

Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis

• Marcus Frings,
• Isabelle Thomé and
• Carsten Bolm

Beilstein J. Org. Chem. 2012, 8, 1443–1451, doi:10.3762/bjoc.8.164

• condensation reaction in an asymmetric fashion. Using a slightly modified procedure of the thiourea-catalyzed Biginelli reaction developed by Miao and Chen [69], we chose the condensation between urea, benzaldehyde (1.5 equiv), and ethyl acetoacetate (3 equiv) to give dihydropyrimidine 20 (Table 1) as test

Synthesis of diverse dihydropyrimidine-related scaffolds by fluorous benzaldehyde-based Biginelli reaction and post-condensation modifications

• Bruno Piqani and
• Wei Zhang

Beilstein J. Org. Chem. 2011, 7, 1294–1298, doi:10.3762/bjoc.7.150

• are used as common intermediates for post-condensation modifications such as cycloaddition, Liebeskind–Srogl reaction and Suzuki coupling to form biaryl-substituted dihydropyrimidinone, dihydropyrimidine, and thiazolopyrimidine compounds. The high efficiency of the diversity-oriented synthesis is

• achieved by conducting a multicomponent reaction for improved atom economy, under microwave heating for fast reaction, and with fluorous solid-phase extractions (F-SPE) for ease of purification. Keywords: Biginelli reaction; dihydropyrimidine; diversity-oriented synthesis; fluorous; Suzuki coupling

• ; Introduction Dihydropyrimidinone and dihydropyrimidine derivatives have broad biologically activities. Many synthetic samples have been studied as antibacterial, antiviral, antihypertensive, and anticancer agents [1], and the natural products containing these heterocyclic moieties have been studied as new

The Eschenmoser coupling reaction under continuous-flow conditions

• Sukhdeep Singh,
• J. Michael Köhler,
• Andreas Schober and
• G. Alexander Groß

Beilstein J. Org. Chem. 2011, 7, 1164–1172, doi:10.3762/bjoc.7.135

• [13], were prepared by utilization of the Eschenmoser coupling reaction. Recently, we explored the Eschenmoser coupling in order to produce Biginelli type dihydropyrimidine (DHPM) derivatives as screening candidates for pharmaceutical and crop science research [14]. Moreover, the Eschenmoser coupling

• quantitatively S-alkylated but decomposed during the sulfide-contraction step and subsequent workup. Therefore, we could not isolate the desired product 4ad. The reaction of dihydropyrimidine substrates 2e and 2f proceeded in a facile way, and the desired products 3ae and 3af were isolated in good yields. Even

• bromoketones because of their known good reactivity and selectivity for the sulfide contraction [1]. Recently, we investigated the reaction of dihydropyrimidine derivatives of type 11 with different aliphatic ketones 10 under batch conditions. In that case the S-alkylated substrates 12 did not undergo the