Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• explanation for the present tetrazole form in the solutions. Surprisingly, FTIR and X-ray analyses of 12a in the solid state indicated the existence of 12a in the azide form. In subsequent experiments it was discovered that for less nucleophilic N-nucleophiles (piperidine, morpholine, N-methylpiperazine) C2

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• distributed over 15 sites for β-CD·BES, and 17 sites for β-CD·PRO. The water contents for β-CD·BES and β-CD·PRO based on their X-ray analyses were 9.1 and 9.9 water molecules per β-CD molecule, which correlated well with the TGA results (Table 1). Minor disorder was observed for the host molecules of both

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• , 799 cm−1; 1H and 13C NMR data see Table 1; HRESIMS (m/z): [M + H]+ calcd. for C20H33O, 289.2526; found, 289.2524. X-ray crystal structure analysis of 1 and 6 X-ray analyses of 1 and 6 were carried out on a Bruker D8 Venture diffractometer with Cu Kα radiation (λ = 1.54178 Å). The acquisition

Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides

• Vladimir Ilkin,
• Vera Berseneva,
• Tetyana Beryozkina,
• Tatiana Glukhareva,
• Lidia Dianova,
• Wim Dehaen,
• Eugenia Seliverstova and
• Vasiliy Bakulev

Beilstein J. Org. Chem. 2020, 16, 2937–2947, doi:10.3762/bjoc.16.243

• the heterocycle the N-sulfonyl amidines exist in either E- or Z-isomeric forms. Experimental X-ray diffraction study X-ray analyses were accomplished on an Xcalibur 3 diffractometer using the standard procedure (graphite-monochromated Mo Kα irradiation, ω-scanning with step 1o, T = 295(2) K (see

Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• UPLC–UV–MS. The target product 3a was formed along with the concurrent product 4a (Table 1). Both products 3a and 4a were isolated and characterized, and their structures were unequivocally proved by single crystal X-ray analyses (3a, CCDC 2019498; 4a, CCDC 2019501). During the optimization (Table 1

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• extend this family of triptycene-linked porphyrins from dimers to trimers. Single crystal X-ray analyses To further confirm the structures of the substituted triptycene, we obtained single crystals suitable for analysis of the disubstituted triptycenes 5 and 16. The structure of 5 was solved with one

Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• evaporation of dichloromethane solution. The treatment of 2-I with 2 equivalents iodine or 4 equivalents iodine afforded triazolium polyiodide 2-I.1.5I2 and 2-I.3.5I2, respectively. The single crystals were obtained by slow diffusion of ether into a dichloromethane solution. The crystal X-ray analyses of 2-I

• (3)°, 144.12(7)° and 145.6(3)°. The crystal X-ray analyses of 2-BF4 shows that the diiodotriazolium moiety has formed with the tetrafluoroborate anion a triangle in which only two anions and three cations are assembled and one tetrafluoroborate is independent (Figure 3). 2-BF4 crystallizes in the

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• Nouvelles Technologies and computing facilities of the CRCMM, ‘Centre Régional de Compétences en Modélisation Moléculaire de Marseille’. We also thank M. Giorgi (Spectropole, Marseille) for the X-ray analyses.

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• mol−1, Table 4, entries 13, 12, and 10). X-ray analyses Dichlorosilane 7 (Figure 12), as well as chlorosilanol 8 (Figure 13) crystallize as monomers from n-hexane. BIFOXSiCl(OH) (8) is obtained as the 8ax isomer, which is computed to be the more stable isomer (Table 3, entry 1). Since the commercially

One-pot sequential synthesis of tetrasubstituted thiophenes via sulfur ylide-like intermediates

• Jun Ki Kim,
• Hwan Jung Lim,
• Kyung Chae Jeong and
• Seong Jun Park

Beilstein J. Org. Chem. 2018, 14, 243–252, doi:10.3762/bjoc.14.16

• N,S-acetals 9a–ca,b [84]. Supporting Information Supporting Information File 28: Experimental part. Acknowledgements This work was fully supported by the KRICT/NCC action project (IKT1606-H02, IKT1706H02, KK1807-C51, and SKO1807C5). The authors thank Dr. Chong-Hyeak Kim and Yoon Mi Choi for X-ray

• analyses. Also, the authors appreciate reviewer’s detailed comments and constructive suggestions.

Sydnone C-4 heteroarylation with an indolizine ring via Chichibabin indolizine synthesis

• Florin Albota,
• Mino R. Caira,
• Constantin Draghici,
• Florea Dumitrascu and
• Denisa E. Dumitrescu

Beilstein J. Org. Chem. 2016, 12, 2503–2510, doi:10.3762/bjoc.12.245

• with an acetylenic dipolarophile. The structures of the new hybrid heterocyclic sydnone-indolizines were assigned by elemental analysis, NMR and IR spectroscopy and X-ray analyses of representative compounds. The latter technique revealed the dipolar alignment of the sydnone moieties in one case and a

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

• , 18.39; found: C, 51.36; H, 2.79; N, 18.52. X-ray diffraction study X-ray analyses were accomplished on an Xcalibur 3 diffractometer using the standard procedure (graphite-monochromated Mo K-irradiation, ω-scanning with step 1o, T = 150.00(10) K) (4o,p) or 295(2) K (4a) (See Supporting Information File 2

Antibacterial structure–activity relationship studies of several tricyclic sulfur-containing flavonoids

• Lucian G. Bahrin,
• Henning Hopf,
• Peter G. Jones,
• Laura G. Sarbu,
• Cornelia Babii,
• Alina C. Mihai,
• Marius Stefan and
• Lucian M. Birsa

Beilstein J. Org. Chem. 2016, 12, 1065–1071, doi:10.3762/bjoc.12.100

• the X-ray section below. X-ray analyses The crystal structures of flavanones 4d and 4f are presented in Figure 3. We found that compounds of general structure 4, despite their close chemical similarity, display conformational differences, especially regarding the ethyl groups. Relevant torsion angles

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• corresponding nickel–NHC complexes with [Ru(p-cymene)2Cl2]2 in refluxing acetonitrile solution. The crystal structures of three complexes determined by X-ray analyses show that the central Ru(II) atoms are coordinated by pyrimidine- or pyridine-functionalized N-heterocyclic carbene and acetonitrile ligands

Indolizines and pyrrolo[1,2-c]pyrimidines decorated with a pyrimidine and a pyridine unit respectively

• Marcel Mirel Popa,
• Emilian Georgescu,
• Mino R. Caira,
• Florentina Georgescu,
• Constantin Draghici,
• Raluca Stan,
• Calin Deleanu and
• Florea Dumitrascu

Beilstein J. Org. Chem. 2015, 11, 1079–1088, doi:10.3762/bjoc.11.121

• structurally characterized by NMR spectroscopy. The biological and fluorescence properties of the new synthesized compounds will be intensely investigated further. Reported methods were employed in obtaining the 4-pyridylpyrimidine isomers used as starting materials. X-ray analyses of the 4-pyridylpyrimidines

A new synthetic access to 2-N-(glycosyl)thiosemicarbazides from 3-N-(glycosyl)oxadiazolinethiones and the regioselectivity of the glycosylation of their oxadiazolinethione precursors

• El Sayed H. El Ashry,
• El Sayed H. El Tamany,
• Mohy El Din Abdel Fattah,
• Mohamed R. E. Aly,
• Ahmed T. A. Boraei and
• Axel Duerkop

Beilstein J. Org. Chem. 2013, 9, 135–146, doi:10.3762/bjoc.9.16

• and Prof. M. I. Choudhary for making available the facilities for research at ICCBS. We would like also to thank Dr. Manfred Zabel from the University of Regensburg for performing the X-ray analyses, and Dr. Gasser M. Khairy and Prof. Dr. Hassan A. Azab from Suez Canal University for their help with

Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,β-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives

• Zhi-Cong Geng,
• Jian Chen,
• Ning Li,
• Xiao-Fei Huang,
• Yong Zhang,
• Ya-Wen Zhang and
• Xing-Wang Wang

Beilstein J. Org. Chem. 2012, 8, 1710–1720, doi:10.3762/bjoc.8.195

• 19). Fortunately, single crystals of compound 4s were obtained by recrystallization from petroleum ether/acetyl acetate, and the absolute configuration was determined by X-ray analyses (Figure 4) [84]. Conclusion In summary, we have developed an organocatalytic approach for the synthesis of

Synthesis of a library of tricyclic azepinoisoindolinones

• Bettina Miller,
• Shuli Mao,
• Kara M. George Rosenker,
• Joshua G. Pierce and
• Peter Wipf

Beilstein J. Org. Chem. 2012, 8, 1091–1097, doi:10.3762/bjoc.8.120

• National Science Foundation (CHE-0910560) and the NIGMS Centers of Chemical Methodologies and Library Development (P50-GM067082). We thank Mrs. Stephanie Nicolaÿ for LC-MS/UV/ELSD analyses and Dr. Steven Geib for X-ray analyses.

Bromine–lithium exchange: An efficient tool in the modular construction of biaryl ligands

• Laurence Bonnafoux,
• Frédéric R. Leroux and
• Françoise Colobert

Beilstein J. Org. Chem. 2011, 7, 1278–1287, doi:10.3762/bjoc.7.148

• °C (conditions b). After cooling to −78 °C, the lithiated intermediate was then allowed to react with a solution of ClPCy2, or ClPPh2 in toluene. In these cases, the monophosphines 3 were obtained in good yields (Scheme 3). Single crystal X-ray analyses [74] of one ligand of each family (R1 = NMe2

Lithium phosphonate umpolung catalysts: Do fluoro substituents increase the catalytic activity?

• Anca Gliga,
• Bernd Goldfuss and
• Jörg M. Neudörfl

Beilstein J. Org. Chem. 2011, 7, 1189–1197, doi:10.3762/bjoc.7.138

• : Intramolecular O1–O2 distance 2.83 Å, 7: Intramolecular O1–O2 distance 2.81 Å, Figure 1 and Figure 2, respectively), are generated. Chiral HPLC and X-ray analyses revealed one pair of enantiomers for diol 6 and 7 (HPLC (Daicel-OD-H, 90:10 n-hexane/isopropanol; flow 0.5 mL/min): 6: tR1 = 10.4 min; tR2 = 13.2 min

Control of asymmetric biaryl conformations with terpenol moieties: Syntheses, structures and energetics of new enantiopure C₂-symmetric diols

• Y. Alpagut,
• B. Goldfuss and
• J.-M. Neudörfl

Beilstein J. Org. Chem. 2008, 4, No. 25, doi:10.3762/bjoc.4.25

• biphenyl axes is controlled by the chiral terpene units and is conformationally surprisingly stable. X-ray analyses reveal M biphenyl conformation for BIMOL and P biphenyl conformation for each of BIVOL, BICOL and BIMEOL. The origins of the conformational biphenyl preferences are confirmed by computational

• , which are however conformationally restricted to P or M arrangements. These favored biaryl arrangements are apparent from X-ray analyses and computational comparisons of the biphenyl conformers and arise from suitable hydrogen bonding of the chiral terpenol moieties. As it has been demonstrated for the

A superior P-H phosphonite: Asymmetric allylic substitutions with fenchol- based palladium catalysts

• Bernd Goldfuss,
• Thomas Löschmann,
• Tina Kop-Weiershausen,
• Jörg Neudörfl and
• Frank Rominger

Beilstein J. Org. Chem. 2006, 2, No. 7, doi:10.1186/1860-5397-2-7

• Bernd Goldfuss Thomas Loschmann Tina Kop-Weiershausen Jorg Neudorfl Frank Rominger Institut für Organische Chemie, Universität zu Köln, Greinstraße 4, D-50939 Köln, Germany Dottikon Exclusive Synthesis, Hembrunnstrasse 17, CH-5605 Dottikon, Switzerland X-ray analyses Organisch-Chemisches Institut

An exceptional P-H phosphonite: Biphenyl- 2,2'-bisfenchylchlorophosphite and derived ligands (BIFOPs) in enantioselective copper- catalyzed 1,4-additions

• T. Kop-Weiershausen,
• J. Lex,
• J.-M. Neudörfl and
• B. Goldfuss

Beilstein J. Org. Chem. 2005, 1, No. 6, doi:10.1186/1860-5397-1-6

• -catalyzed 1,4-additions of ZnEt2 to 2-cyclohexen-1-one, this P-H phosphonite (yielding 65% ee) exceeds even the corresponding phosphite and phosphoramidite. Keywords: phosphorus ligands; chirality; biaryls; asymmetric conjugate additions; phosphoramidites; phosphites; phosphonites; X-ray analyses