Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• scaffold can be found in many biologically active compounds and natural products such as 1-epiaustraline, hyacinthacine A1, (−)-isoretronecanol, and (−)-supinidine (Figure 2) [68][69]. After the method development work, a pseudo-five-component double cycloaddition reaction of glycine with two equivalents

• ) [70]. We expected that using olefinic oxindoles 14 as alkenes for the [3 + 2] cycloaddition could afford spirooxindole-pyrrolizidines. The method development revealed that recyclable zeolite HY acid is a good catalyst for the cycloaddition [70]. Thus, the zeolite HY-catalyzed reaction of glycine with

• scaffolds. α-Substituted amino acids, such as 2-aminoisobutyric acid, could be used to block the second cycloaddition. Shown in Scheme 12 is a method development for the stepwise synthesis of triazolobenzodiazepines. The reaction of 2-azidobenzaldehyde, 2-aminoisobutyric acid and N-ethylmaleimide in MeCN

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• report, it augured the potential of RLT to be a general strategy in synthetic method development, with modern examples including new alkene addition reactions and decarboxylative functionalizations (Scheme 2). Recent applications of RLT in catalysis Upon the discovery and initial exploration of the RLT

• valuable homodifunctionalized products using unactivated alkenes. Vicinal diazides (and to a lesser extent dihalides) have been popular targets for modern method development. Both photochemical [33] and electrochemical [34][35][36] methods have been effective in delivering products containing these

• adventitious discovery of nitrate functioning as a mild and selective oxidant in RLT catalytic systems presents many opportunities for future method development and are avidly pursuing this area of research. Outlook After scant exploration following its elucidation in early mechanistic studies of bioinorganic

Modern flow chemistry – prospect and advantage

• Philipp Heretsch

Beilstein J. Org. Chem. 2023, 19, 33–35, doi:10.3762/bjoc.19.3

• Philipp Heretsch Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany 10.3762/bjoc.19.3 Keywords: flow chemistry; method development; reactor design; Organic chemistry has shaped modern society by fulfilling the basic needs for pharmaceuticals

• chemicals. This has again led to improved scalability, higher purity of products, and eventually decreased manufacturing costs. From the undisputed role of continuous flow chemistry for process chemists, the advent of this technology in academic research laboratories, especially for method development and

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• fourth and final step, phenoxydiphenylalkene derivative 4a was prepared by a Wittig reaction, which was carried out using methyltriphenylphosphonium bromide with ketone 3a, in basic medium, at room temperature, and dry THF. After the structures of the starting compounds were elucidated, the method

• development trials for the synthesis of xanthene derivatives were carried out. For this purpose, catalyst researches were carried out using compound 4a. An intramolecular Friedel–Crafts reaction was tried by activating the alkene with various organic Brønsted acids and Lewis acids (Table 1). In the reaction

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• as the phosphine-catalyzed [3 + 2] cycloaddition [17], platinum-catalyzed [3 + 2] cycloaddition [18], and Rhodium-catalyzed [3 + 2] cycloaddition [12], were invented and have been extensively used in natural product synthesis in the last decade. Many reviews focusing the method development of the all

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• would be quite appealing to a wider range of organic chemists in academia and industrial R&D sectors working in the field of heterocyclic syntheses. In a nutshell, this review will be a guiding torch to envisage: (i) the role of various transition metals in the domain dedicated towards method

• development and (ii) for the modifications needed thereof in the R&D sector. Keywords: C–H activation/functionalization; coupling reactions; imidazopyridines; multicomponent reactions; transition metal catalysis; Introduction The structural diversity and biological importance of nitrogen-containing

Synthesis of trifluoromethylated 2H-azirines through Togni reagent-mediated trifluoromethylation followed by PhIO-mediated azirination

• Jiyun Sun,
• Xiaohua Zhen,
• Huaibin Ge,
• Guangtao Zhang,
• Xuechan An and
• Yunfei Du

Beilstein J. Org. Chem. 2018, 14, 1452–1458, doi:10.3762/bjoc.14.123

• -dimethyl-1,2-benziodoxole (1’, Figure 2), are effective and efficient hypervalent iodine reagents for trifluoromethylation reactions of a variety of substrates [22][23]. These reagents have found wide applications in the area of organofluorine chemistry, synthetic method development as well as medicinal

The effect of cyclodextrin complexation on the solubility and photostability of nerolidol as pure compound and as main constituent of cabreuva essential oil

• Joyce Azzi,
• Pierre-Edouard Danjou,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2017, 13, 835–844, doi:10.3762/bjoc.13.84

• donated by Ligand Pharmaceuticals Incorporated (La Jolla, USA). Methanol HPLC-grade was purchased from VWR Chemicals (Atlanta, United States). Methods HPLC assay Chromatographic analysis was performed with a Waters 600E multisolvent delivery system HPLC. The method development for estimation of Ner

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

• Luíse Azevedo,
• Larissa Faqueti,
• Marina Kritsanida,
• Antonia Efstathiou,
• Despina Smirlis,
• Gilberto C. Franchi Jr,
• Grégory Genta-Jouve,
• Sylvie Michel,
• Louis P. Sandjo,
• Raphaël Grougnet and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

• spraying with sulfuric vanillin solution at 30% and heating. The mobile phase used to monitor the method development and the fractions was composed by EtOAc/CH2O2/AcOH/H2O (60:0.6:0.6:20). The 1D and 2D NMR experiments were recorded with Bruker AC-300 and Bruker Avance-400 spectrometers at 400 MHz for 1H

Multigramme synthesis and asymmetric dihydroxylation of a 4-fluorobut-2E-enoate

• James A. B. Laurenson,
• John A. Parkinson,
• Jonathan M. Percy,
• Giuseppe Rinaudo and
• Ricard Roig

Beilstein J. Org. Chem. 2013, 9, 2660–2668, doi:10.3762/bjoc.9.301

• and enantioselectivities [25]. Figure 2 shows the panel of ligands used for the asymmetric transformations. Scheme 5 shows the initial dihydroxylation carried out on 25, and Table 1 summarises the method development. The asymmetric dihydroxylation conditions were subject to some optimization; the

Mild and efficient cyanuric chloride catalyzed Pictet–Spengler reaction

• Ashish Sharma,
• Mrityunjay Singh,
• Nitya Nand Rai and
• Devesh Sawant

Beilstein J. Org. Chem. 2013, 9, 1235–1242, doi:10.3762/bjoc.9.140

• h; (b) Zn, AcOH-EtOH, 60 °C, 4 h. Method development of the TCT-catalyzed Pictet–Spengler reaction for the condensation of tryptamine (1) and 4-tolualdehyde (2a). Condensation of the Pictet–Spengler substrates 1 and 4 (1 equiv) with aldehyde (1 equiv) in the presence of TCT (20 mol %) in DMSO under

Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy

• Huili Liu,
• Kuan Zheng,
• Xiang Lu,
• Xiaoxia Wang and
• Ran Hong

Beilstein J. Org. Chem. 2013, 9, 983–990, doi:10.3762/bjoc.9.113

• efforts on method development toward the efficient construction of velbanamine-type indole alkaloids. As shown in Scheme 2, an intramolecular Heck reaction (via 9-exo manner) would finalize the 9-membered ring, which was biogenetically derived from a retro-Mannich reaction from catharanthine (Scheme 1

Synthesis and stability study of a new major metabolite of γ-hydroxybutyric acid

• Ida Nymann Petersen,
• Jesper Langgaard Kristensen,
• Christian Tortzen,
• Torben Breindahl and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2013, 9, 641–646, doi:10.3762/bjoc.9.72

• demonstrated to be highly stabile towards aqueous hydrolysis within the pH range normally observed for urine even at elevated temperature for several days, making it suitable for method development within analytical and forensic chemistry. Experimental General For reactions conducted under anhydrous conditions

Antibiotic and cytotoxic peptides

• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 1144–1145, doi:10.3762/bjoc.8.127

• in Medicinal Chemistry [2]. This Thematic Series on “Antibiotic and cytotoxic peptides” presents contributions from synthetic chemists active in the fields of peptides, peptidomimetics, drug design, and method development, in order to promote the research area further and to disseminate the

A new and facile synthetic approach to substituted 2-thioxoquinazolin-4-ones by the annulation of a pyrimidine derivative

• Nimalini D. Moirangthem and
• Warjeet S. Laitonjam

Beilstein J. Org. Chem. 2010, 6, 1056–1060, doi:10.3762/bjoc.6.120

• are of much interest due to their biological activities [1][2]. Additionally, quinazolines are interesting targets for new method development due to their importance in numerous therapeutic areas. Recently, antitumor [3] and anti-HIV activities [4][5] of quinazolines have been described. A large

A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• ], polymolybdophosphoric acid supported silica [99], TsOH [100], FeCl3 [101][102], BiCl3 [103], Sc(OTf)3 [104] other Ru- or [105][106][107], Re-complexes [108] and even molecular iodine [109]. Toste and co-workers developed a mild rhenium-catalyzed propargylation of electron-rich arenes. In addition to principal method

• development, the authors applied their procedure towards the synthesis of several biologically active molecules. Starting from ethyl propiolate 95 and safrole 94, the desired FC alkylation product 96 was isolated in 66% yield. A subsequent six-step synthesis yielded β-apopicropodophyllin (97), a previously