Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

• Juraj Dobiaš,
• Marek Ondruš,
• Gabriela Addová and
• Andrej Boháč

Beilstein J. Org. Chem. 2017, 13, 1350–1360, doi:10.3762/bjoc.13.132

• characterised as regioisomeric mixtures [22]. Nevertheless, most of the nonsymmetrical 3,4-dihydroquinoxalin-2(1H)-ones are required in their pure form (Figure 1). To the best of our knowledge, there is only one paper which deals with the regioselective synthesis of 3-acylmethylidene-3,4-dihydroquinoxalin-2(1H

• ) (natively preferring SYN regioselectivity, see Table 1, entry 4, column 3) complicated the desired reaction. The other possibility was to perform the regioselective synthesis of 17d (ANTI) from an appropriate furan-2,3-dione 13 (Scheme 2). The preparation of 13 failed in our hands. Therefore, we decided to

• or the contrary regioselectivity of activated species 12c,d (prepared in situ from appropriate 12 by DMAP – 12c or HOBt/DIC additives – 12d) (Scheme 6). Conclusion Simple reaction conditions were discovered for predictable and switchable highly regioselective synthesis of 3,4-dihydroquinoxaline-2(1H

Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

• Serena Traboni,
• Emiliano Bedini and
• Alfonso Iadonisi

Beilstein J. Org. Chem. 2016, 12, 2748–2756, doi:10.3762/bjoc.12.271

• amount of TBAB, pyridine and TBDMSCl, the regioselective synthesis of di-O-TBDMS derivatives was achieved at 50 °C in satisfying yields from glycosides 1 and 3 (Table 3, entries 1 and 2), and glycal 8 (entry 3). Double silylation at primary positions of the disaccharide lactoside 20 [60] also proved

Combined experimental and theoretical studies of regio- and stereoselectivity in reactions of β-isoxazolyl- and β-imidazolyl enamines with nitrile oxides

• Ilya V. Efimov,
• Marsel Z. Shafikov,
• Nikolai A. Beliaev,
• Natalia N. Volkova,
• Tetyana V. Beryozkina,
• Wim Dehaen,
• Zhijin Fan,
• Viktoria V. Grishko,
• Gert Lubec,
• Pavel A. Slepukhin and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2016, 12, 2390–2401, doi:10.3762/bjoc.12.233

• contrast to our approach, these methods are not applicable for the regioselective synthesis of compounds containing a 3-aryl-4-carboxyisoxazole fragment, a structural motif in the anticancer pyrazolylisoxazole, and rather the 3,5-disubstituted isoxazole (compound 5, Scheme 2) is expected [12]. The presence

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Regioselective synthesis of chiral dimethyl-bis(ethylenedithio)tetrathiafulvalene sulfones

• Flavia Pop and
• Narcis Avarvari

Beilstein J. Org. Chem. 2015, 11, 1105–1111, doi:10.3762/bjoc.11.124

Copper–phenanthroline catalysts for regioselective synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and of pyrrolo[1,2-a]phenanthrolines under mild conditions

• Rupankar Paira,
• Tarique Anwar,
• Maitreyee Banerjee,
• Yogesh P. Bharitkar,
• Shyamal Mondal,
• Sandip Kundu,
• Abhijit Hazra,
• Prakas R. Maulik and
• Nirup B. Mondal

Beilstein J. Org. Chem. 2014, 10, 692–700, doi:10.3762/bjoc.10.62

The regioselective synthesis of spirooxindolo pyrrolidines and pyrrolizidines via three-component reactions of acrylamides and aroylacrylic acids with isatins and α-amino acids

• Tatyana L. Pavlovskaya,
• Fedor G. Yaremenko,
• Victoria V. Lipson,
• Svetlana V. Shishkina,
• Oleg V. Shishkin,
• Vladimir I. Musatov and
• Alexander S. Karpenko

Beilstein J. Org. Chem. 2014, 10, 117–126, doi:10.3762/bjoc.10.8

• of compound 7a. The mechanism of the regioselective synthesis of compounds 4 and 6. The synthesis of compounds 7a–7c. Tentative reaction mechanism for the decarboxylative cyclative rearrangement of the initial three-component product. Three-component synthesis of spirooxindoles 4a–4g. Synthesis of

Silica: An efficient catalyst for one-pot regioselective synthesis of dithioethers

• Samir Kundu,
• Babli Roy and
• Basudeb Basu

Beilstein J. Org. Chem. 2014, 10, 26–33, doi:10.3762/bjoc.10.5

Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold

• Nikolay T. Tzvetkov,
• Harald Euler and
• Christa E. Müller

Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

• Esteban P. Urriolabeitia,
• Eduardo Laga and
• Carlos Cativiela

Beilstein J. Org. Chem. 2012, 8, 1569–1575, doi:10.3762/bjoc.8.179

• Esteban P. Urriolabeitia Eduardo Laga Carlos Cativiela Instituto de Síntesis Química y Catálisis Homogénea, CSIC - Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain 10.3762/bjoc.8.179 Abstract A new method for the regioselective synthesis of 2-alkoxycarbonyl- and 2-(aminocarbonyl

Selectivity in C-alkylation of dianions of protected 6-methyluridine

• Ngoc Hoa Nguyen,
• Christophe Len,
• Anne-Sophie Castanet and
• Jacques Mortier

Beilstein J. Org. Chem. 2011, 7, 1228–1233, doi:10.3762/bjoc.7.143

• , Transformations intégrées de la matière renouvelable, EA 4297 UTC/ESCOM, 1 allée du réseau Jean-Marie Buckmaster, 60200 Compiègne, France 10.3762/bjoc.7.143 Abstract A regioselective synthesis of 6-ω-alkenyluridines 3, precursors of potent antiviral and antitumor cyclonucleosides 5, is described. While ω-alkenyl

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• , respectively, with tert-butyl cyanoacetate (14), as illustrated in Scheme 5 [36]. Baraldi et al. [37] utilized this method for the regioselective synthesis of 2-alkyl- or 2-aryl-3-aminothieno[3,4-c]pyrazoles 19. Several alkyl- or arylhydrazine hydrochlorides on condensation with 4-cyano-3

• cyanoacetaldehyde (7) with hydrazines. Synthesis of 5-aminopyrazoles and their sulfonamide derivatives. Synthesis of 5-aminopyrazoles, containing a cyclohexylmethyl- or phenylmethyl- sulfonamido group at position-3. Regioselective synthesis of 3-amino-2-alkyl (or aryl) thieno[3,4-c]pyrazoles 19. Solid supported

Pd/C-mediated synthesis of α-pyrone fused with a five-membered nitrogen heteroaryl ring: A new route to pyrano[4,3-c]pyrazol-4(1H)-ones

• Dhilli Rao Gorja,
• Venkateswara Rao Batchu,
• Ashok Ettam and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 64, doi:10.3762/bjoc.5.64

• (PPh3)2 and CuI did not provide the 7-alkynyl substituted derivative of 3 possibly due to the “peri” effect caused by the N-1 methyl group of the pyrazole ring. Conclusions In conclusion, we have developed a new, straightforward and general method for the regioselective synthesis of novel 6-substituted

Diels- Alder reactions using 4,7-dioxygenated indanones as dienophiles for regioselective construction of oxygenated 2,3-dihydrobenz[f]indenone skeleton

• Natsuno Etomi,
• Takuya Kumamoto,
• Waka Nakanishi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2008, 4, No. 15, doi:10.3762/bjoc.4.15

• ], regioselective synthesis of 4,8,9-trioxygenated 2,3-dihydrobenz[f]indenone 4 [22] was a key issue, which was achieved via C ring construction with intramolecular Friedel-Crafts reaction of naphthalenepropanoic acid 5 (path A, Scheme 1) [23]. However, the utilization of a stoichiometric amount of expensive silver

• regioselective synthesis of the desired 4,8,9-trioxygenated ones. Results and Discussion In the quinone route, we designed several indanetriones to modulate steric and electronic factors; i.e. 1,4,7-indanetrione 8, the 6-brominated quinone 12, and the corresponding 4-monoacetals 13 and 14 (Scheme 2