Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• guanidine C. Finally, the intramolecular cyclization of the guanidine moiety and the carbonyl group leads to the target pyrimidine 9. After the general synthetic method for pyrimidines containing the allomaltol fragment had been established, the photochemical behavior of the obtained compounds 9 was

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• reactions, and C–H functionalizations ([3] and references therein), leading to the synthesis of diverse nitrogen heterocycles of pharmaceutical relevance [4]. The traditional synthetic method for the preparation of N-arylsulfonylimines, similar to the preparation of N-arylimines, is based on the

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• ; palladium; synthetic method; Introduction Nowadays, fluorinated molecules represent an indispensable class of molecules in chemistry and in chemical biology. Thanks to the unique properties of the fluorine atom or fluorinated groups to modulate biological and physicochemical properties of the parent non

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• alternative approaches exist. The direct dehydrogenation of 1,4-dithiane is somewhat cumbersome [25], and, moreover, 1,4-dithiane (1) is surprisingly not available in large quantities at a reasonable cost, in spite of its apparent simplicity. Our lab has found that the synthetic method for dihydrodithiins

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• is mediated by visible light irradiation. A wide range of substrates bearing different substituents and derived from ubiquitous carboxylic acids, including α-amino acids, were synthesized and examined under this very mild, efficient, and cost effective transition-metal-free synthetic method. These

• can operate as an efficient photoredox catalyst, providing an economical access to construct important oxindole scaffolds containing a quaternary carbon center. This synthetic method features a broad substrate scope, good functional group tolerance and operational simplicity. Mechanistic

On drug discovery against infectious diseases and academic medicinal chemistry contributions

• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 1355–1378, doi:10.3762/bjoc.18.141

• patents just because of a lack of a simple synthetic method. Our contribution to alleviate this “blind spot” was an extensive exploration of the chemistry of alkoxypyrazoles (C) which provided synthetic building blocks useful to reach, amongst others, many new chemical entities with the general formula B

Dienophilic reactivity of 2-phosphaindolizines: a conceptual DFT investigation

• Nosheen Beig,
• Aarti Peswani and
• Raj Kumar Bansal

Beilstein J. Org. Chem. 2022, 18, 1217–1224, doi:10.3762/bjoc.18.127

• ; Fukui function; global hardness; nucleophilicity index; 2-phosphaindolizines; Introduction In 1988, we developed a simple synthetic method for the synthesis of 1,3-azaphospholo[1,5-a]pyridine derivative (1, R1 = Me, R2 = PhCO) from the reaction of 2-ethyl-1-phenacylpyridinium bromide with PCl3 and Et3N

Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes

• Mana Kitano,
• Tsuyoshi Saitoh,
• Shigeru Nishiyama,
• Yasuaki Einaga and
• Takashi Yamamoto

Beilstein J. Org. Chem. 2022, 18, 1154–1158, doi:10.3762/bjoc.18.119

• , first reported in 1944 [3], a wide variety of catalytic systems are still being reported [4][5][6][7][8][9][10][11][12]. Electro-organic synthesis refers to an organic synthetic method combined with electrochemistry [13][14]. A striking feature in electro-organic synthesis is the use of electricity as a

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• -triisopropylphenyl)phosphinyl azide (17) gave the corresponding 2,3-dihydrobenzo[c][1,2]azaphosphole 1-oxide 18 in 51% and phosphonamidate 19 in 28% yield (Scheme 4). The synthetic method was applied occasionally [24]. P-Stereogenic 3-arylmethylidene-2,3-dihydrobenzo[c][1,2]azaphosphole 1-oxides 21 and 23 were

• -oxides 56a in 23% and 93 in 63% yields, respectively, showing the limited scope of the synthetic method (Scheme 17) [39]. Ring-closing metathesis (RCM) is an efficient strategy for the construction of cyclic compounds via the formation of a C=C bond [40][41], which can be reduced to the C–C bond. 2

• synthetic method showed very limited substrate scope. Only less bulky primary amines underwent the first aza-Michael addition and then intramolecular nucleophilic substitution. However, aromatic amines, aniline, 2,3-dihydro-1H-inden-4-amine, and the bulky aliphatic primary amine adamantylamine did not

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• )2-bb-DTT, (TMS)2-bb-DST, and (TMS)2-bb-DSS as starting materials. The synthetic method described in this research not only provides a method for the synthesis of S- shaped double helicenes but also enriches the family of selenophene helicenes. Multiple intermolecular interactions and regular

Rapid gas–liquid reaction in flow. Continuous synthesis and production of cyclohexene oxide

• Kyoko Mandai,
• Tetsuya Yamamoto,
• Hiroki Mandai and
• Aiichiro Nagaki

Beilstein J. Org. Chem. 2022, 18, 660–668, doi:10.3762/bjoc.18.67

• conventional batch technique has irreconcilable limitations. Cyclohexene oxide is one of the key starting materials for manufacturing various functional organic compounds and materials such as polymers and chiral organic compounds with cyclohexane moiety [2][3][4][5][6]. Thus, an efficient and fast synthetic

• method for the production of cyclohexene oxide is highly desired to be developed, taking sustainability for the environment and our society into consideration. The general synthetic procedure for cyclohexene oxide is the epoxidation of cyclohexene [7][8]. Among various oxidizing agents used in the

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• (Figure 1) that exhibits efficient orange-to-red TADF [17], and the OLEDs fabricated with POZ-DBPHZ achieved a high EQE up to 16%. However, the role of the number of donors and molecular symmetry in the TADF character of POZ-DBPHZ remained unexplored, due to the lack of a synthetic method to the

• the designed D–A molecule 1, an asymmetric dibenzophenazine electrophile was required. Recently, we have established a synthetic method for such a compound, i.e., 3-trifluoromethanesulfonyldibenzo[a,j]phenazine (DBPHZ-OTf in Scheme 1) to prepare linear-type A–D–A–D compounds [18]. Starting from the

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• programs, we decided to optimize the reaction conditions for the synthesis of the trifluoromethyl-substituted isoxazole 3x. We varied the solvent mixtures and the bases, but kept the reaction temperature at room temperature and the reaction time at 2 hours, because these are the highlights of our synthetic

• method. The results are collected in Table 2. First, we varied the proportion of methanol in the solvent mixture with water to increase the solubility of 4,4,4-trifluoro-1-phenyl-1,3-butanedione (2l). As the percentage of methanol in the solvent mixture increased from 5% to 50%, 75%, and 95%, with DIPEA

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

• Martin Vrbický,
• Karel Macek,
• Jaroslav Pochobradský,
• Jan Svoboda,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

• for 26 (R2 = (−)-bornyl, 44–67%). For these findings we do not have any reliable explanation. Next, the synthetic method [12][13] for the preparation of the target oxazolidine-2-one drugs 1 and 2 from the new chiral intermediates was verified (Scheme 2). For this study, the bornyl derivatives 24 and

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• derivatives, the construction of the naphthoquinone ring is also a viable synthetic method to produce menadione. This is a very efficient strategy with great synthetic value, however, it is less used when compared to other methodologies, as it involves more steps and sometimes more complex reactions. One of

Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor

• Yuki Naito,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39

• and sustainable synthetic method in the face of increasingly stringent environmental and economic constraints. In this context, several groups have demonstrated the electrochemical synthesis of piperidine and pyrrolidine derivatives by anodic oxidation [22][23][24][25][26]. In contrast, there has been

New efficient synthesis of polysubstituted 3,4-dihydroquinazolines and 4H-3,1-benzothiazines through a Passerini/Staudinger/aza-Wittig/addition/nucleophilic substitution sequence

• Long Zhao,
• Mao-Lin Yang,
• Min Liu and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2022, 18, 286–292, doi:10.3762/bjoc.18.32

• /nucleophilic substitution reactions. Compared with the synthetic method to 4H-3,1-benzothiazines in Scheme 1f, we provide another new sequential synthetic route to 4H-3,1-benzothiazines, especially for N,N-disubstituted 2-amino-4H-3,1-benzothiazines. Results and Discussion We initially selected 2

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

• Yelong Lei and
• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 70–76, doi:10.3762/bjoc.18.6

• -oxoalkanoates are used in the reaction, showing specific chemoselectivities controlled by the electronic effect (Scheme 4). Conclusion A new and efficient synthetic method for the synthesis of oxazolines has been developed with alkyl 2-diazo-3-oxoalkanoates and 2-arylaziridines as starting materials. Alkyl 2

First total synthesis of hoshinoamide A

• Haipin Zhou,
• Zihan Rui,
• Yiming Yang,
• Shengtao Xu,
• Yutian Shao and
• Long Liu

Beilstein J. Org. Chem. 2021, 17, 2924–2931, doi:10.3762/bjoc.17.201

• have a relatively simple structure and therefore make an attractive target for further medicinal chemistry studies. To enable these new SAR studies, we need to develop an efficient synthetic method to provide sufficient materials firstly. Hoshinoamide A shows a better antimalarial activity and less

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

• Yuki Yamamoto,
• Akihiro Tabuchi,
• Kazumi Hosono,
• Takanori Ochi,
• Kento Yamazaki,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 2906–2914, doi:10.3762/bjoc.17.198

• synthetic method that relies on a two-phase reaction system. Specifically, lactones are ring-opened and converted into dibromocarboxylic acids when treated with Br2 and a substoichiometric amount of PBr3. Subsequent treatment of these carboxylic acids with a base leads to the corresponding α-bromolactones

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• , this synthetic method (nucleophilic aromatic substitution reaction) is crucial for the development of alternative C–N bond-forming reactions to conventional metal-involved cross-couplings, providing axially chiral N-arylcarbazoles 60 in good yields with remarkable enantiocontrol through a

Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

• Akhil K. Dubey and
• Raghunath Chowdhury

Beilstein J. Org. Chem. 2021, 17, 2642–2649, doi:10.3762/bjoc.17.177

• was found to adopt “(S)” configuration which was unambiguously established by single crystal X-ray diffraction analysis (Figure 1) [45]. To prove the scalability of this synthetic method, we examined the synthesis of 3c and ent-3d in a 1 mmol scale (Scheme 5). The products 3c and ent-3d were isolated

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• of ammonia, formaldehyde, and acetaldehyde; and iii) preparation from furfural and ammonia. In addition, Hantzsch pyridine synthesis from ethyl acetoacetate, formaldehyde, and ammonia is a commonly used laboratory synthetic method. Recently, extensive and efficient methods for the construction of

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• [141] independently demonstrated photoredox/nickel-catalyzed approaches to olefin difunctionalizations involving C(sp3)–H activation. Thus, Kong devised a synthetic method combining nickel catalysis with tetrabutylammonium decatungstate (TBADT) as photocatalyst for the three component reaction of

Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides

• Mathias B. Danielsen and
• Jesper Wengel

Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125

• phosphoramidate and the guanidinobutyl phosphoramidate were synthesized [112]. A facile post-synthetic method was successfully employed to convert amine functionalities attached to ONs into guanidinium tethers. Both, the aminobutyl (76) and guanidinobutyl (77) modifications were introduced into α-ONs which