Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

• Dušan Đ. Škorić,
• Olivera R. Klisurić,
• Dimitar S. Jakimov,
• Marija N. Sakač and
• János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

• , University of Novi Sad, Trg Dositeja Obradovića 4, 21000 Novi Sad, Serbia Oncology Institute of Vojvodina, Faculty of Medicine, University of Novi Sad, Put Dr Goldmana 4, 21204 Sremska Kamenica, Serbia 10.3762/bjoc.17.174 Abstract A practical and high-yielding Schmidt reaction for the synthesis of fused

• selective activity towards certain tumor cell lines. Keywords: antiproliferative activity; Schmidt reaction; steroids; tetrazoles; trimethylsilyl azide; Introduction Bile acids are naturally occurring steroidal surfactants that play various biological roles. Besides the well-known role as lipid

• ]. The main approach in the synthesis of the tetrazoles is 1,3-dipolar cycloaddition between azide and nitrile. These reactions often follow the principles of “click” chemistry [20]. Although the formation of tetrazole in the Schmidt reaction of ketones was noted in the original study by Schmidt himself

Combination of multicomponent KA² and Pauson–Khand reactions: short synthesis of spirocyclic pyrrolocyclopentenones

• Riccardo Innocenti,
• Elena Lenci,
• Gloria Menchi and
• Andrea Trabocchi

Beilstein J. Org. Chem. 2020, 16, 200–211, doi:10.3762/bjoc.16.23

• imposed by the adjacent phenyl and cyclohexyl rings [59]. The treatment of compound 5 under Schmidt reaction conditions with sodium azide in TFA [60] resulted in the conversion to the corresponding six-membered ring lactam 39 in 41% yield, demonstrating the reactivity of the enone 5 at the carbonyl group

A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage

• Kesari Lakshmi Manasa,
• Yellaiah Tangella,
• Namballa Hari Krishna and
• Mallika Alvala

Beilstein J. Org. Chem. 2019, 15, 1864–1871, doi:10.3762/bjoc.15.182

• [6][7], anhydrides [8], esters [9], and acyl azides [10] with amines by employing coupling reagents [11]. Alternative protocols include the Staudinger–Vilarrasa reaction [12], Schmidt reaction [13][14], Beckmann rearrangement [15], aminocarbonylation of aryl halides [16], Staudinger ligation [17

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• anthraquinone–chalcone hybrids were synthesized using Claisen–Schmidt reaction in order to test their anticancer potential against human cancer cell lines and DNA binding affinity and specificity. It has been observed that three conjugates 32–34 exhibited significant cytotoxicity against LS174 and HeLa cancer

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

Synthesis of a tricyclic lactam via Beckmann rearrangement and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha,
• Ongolu Ravikumar and
• Jadab Majhi

Beilstein J. Org. Chem. 2015, 11, 1503–1508, doi:10.3762/bjoc.11.163

• in pure form from ethanol in 20% yield over two steps. Subsequently, we attempted to synthesize the desired lactam 9a via Schmidt reaction or BR of the keto derivative 7 in a single step. In this regard, the tricyclic ketone 7 was treated under different reaction conditions. These include: (a) NaN3

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• diarylpentanoid moiety instead of the natural diarylheptanoid backbone. In some cases, this was amended by a central ring system and was labeled as monocarbonyl analog of curcumin (MACs, Figure 3). Bowen et al. [25] used the Claisen–Schmidt reaction for the synthesis of these analogs. The C7-chain linker between

Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

• László Tóth,
• Yan Fu,
• Hai Yan Zhang,
• Attila Mándi,
• Katalin E. Kövér,
• Tünde-Zita Illyés,
• Attila Kiss-Szikszai,
• Balázs Balogh,
• Tibor Kurtán,
• Sándor Antus and
• Péter Mátyus

Beilstein J. Org. Chem. 2014, 10, 2594–2602, doi:10.3762/bjoc.10.272

• in human neuroblastoma SH-SY5Y cells. Results and Discussion The starting material 4-aryl-2-phenyl-1,4-benzoxazepine (rac-5) for the domino Knoevenagel–[1,5]-hydride shift cyclization reaction was prepared from rac-flavanone (rac-8) in four steps (Scheme 2). The Schmidt reaction of rac-8 was carried

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• –Schmidt reaction at high temperatures and CO2 pressures [13][14][15]. Sodium phenolate is selectively converted to salicylic acid, a precursor of Aspirin, while potassium phenolate exclusively yields p-hydroxybenzoic acid, used in polyester synthesis (Scheme 1) [16][17][18][19][20]. In order to generate

• like process continuity, atom economy and current efficiency. The shortcomings illustrated in this review emphasize the need for more innovative pathways to invent even more efficient and sustainable electrocarboxylation reactions. Synthesis of salicylic acid and p-hydroxybenzoic acid via Kolbe–Schmidt

• reaction [16][17][18][19][20]. Electroreduction of carbon dioxide to formic acid, methanol or methane. Electrochemical fixation of CO2 in olefins. Electrohydrodimerisation of acrylonitrile to adiponitrile [32]. Parallel paired electrosynthesis of phthalide and tert-butylbenzaldehyde dimethylacetal [34

Raman spectroscopy as a tool for monitoring mesoscale continuous-flow organic synthesis: Equipment interface and assessment in four medicinally-relevant reactions

• Trevor A. Hamlin and
• Nicholas E. Leadbeater

Beilstein J. Org. Chem. 2013, 9, 1843–1852, doi:10.3762/bjoc.9.215

• (CH), 129.74 (CH), 130.93 (CH), 133.17 (C), 134.88 (C), 141.48 (CH), 168.00 (C), 194.87 (C) [54]. Typical procedure for monitoring the Claisen–Schmidt reaction Into a 50 mL volumetric flask was added 4-fluorobenzaldehyde (1.551 g, 12.5 mmol, 1 equiv) and acetophenone (1.637 g, 12.5 mmol, 1 equiv

• the Claisen-Schmidt reaction with acetophenone. Product conversion obtained for four aldehyde substrates in the Biginelli reaction with ethyl acetoacetate and urea. Supporting Information Supporting Information File 326: NMR spectra of the isolated products (1, 2a, 3d, 4a), further experimental

Synthetic applications of gold-catalyzed ring expansions

• David Garayalde and
• Cristina Nevado

Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87

• intermolecular nucleophilic attack to give intermediate 47, which upon cycloisomerization affords the aromatic product (Scheme 14, path b). Toste and co-workers reported an intramolecular acetylenic Schmidt reaction using azides as internal nucleophiles to give substituted pyrroles (Scheme 15) [42]. Gold

Synthesis of crispine A analogues via an intramolecular Schmidt reaction

• Ajoy Kapat,
• Ponminor Senthil Kumar and
• Sundarababu Baskaran

Beilstein J. Org. Chem. 2007, 3, No. 49, doi:10.1186/1860-5397-3-49

• Ajoy Kapat Ponminor Senthil Kumar Sundarababu Baskaran Department of Chemistry, Indian Institute of Technology Madras, Chennai-600 036, India 10.1186/1860-5397-3-49 Abstract An intramolecular Schmidt reaction strategy for the synthesis of various derivatives of crispine A using azido-ketone as a

• intramolecular Schmidt reaction of azides with carbonyl compounds.[11][12] Pearson and Aube have exploited the synthetic potential of the intramolecular Schmidt reaction in the synthesis of several indolizidine alkaloids. [11][12][13][14][15] Recently, we reported a novel approach for the construction of the

• (SAR) as well as to improve the efficacy of this novel anti-cancer agent, a flexible approach for the synthesis of various derivatives of crispine A is in great demand (Scheme 2). In 2000, Pearson reported the intramolecular Schmidt reaction based approach for the construction of benzo-fused