Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of vicinal-dichlorides and chlorodienes

• Zhensheng Zhao and
• Graham K. Murphy

Beilstein J. Org. Chem. 2018, 14, 796–802, doi:10.3762/bjoc.14.67

• -dichlorides. Substrates with α-ethyl (2r) and α-isopropyl (2s) substituents reacted similarly, giving chlorinated products in 63–65% yield. Lastly, vinylidene 2t gave chlorodiene 4t as the sole product in 74% yield. As with alkoxy substrate 2m, the α-methylated substrates 2u and 2v possessing methoxy group(s

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• that of sulfinyl imines (S)-25c,d exhibiting an α-benzyloxy substituent provided high diastereoselectivities (76–88% de). This assumed the coordination of the α-alkoxy group to zinc. Even a higher diastereoselectivity of >90% de was achieved for more sterically hindered α-alkoxy-derived substrates (S

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• screened for their cytotoxic activity against human colon carcinoma (Colo-205) cell lines (Scheme 35). Buriol et al. [92] described the reaction of 5-aminopyrazole 16 with 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones 129 to yield pyrazolo[1,5-a]pyrimidine derivatives 130 in acetic acid and ethanol using

• -aminopyrazole derivatives 16/126 with β,γ-unsaturated-γ-alkoxy-α-ketoesters 175 for the regioselective synthesis of pyrazolo[1,5-a]pyrimidines 177 in refluxing ethanol. The reaction provided high regioselectivity compared to other 1,3-dielectrophiles like 1,3-dicarbonyl compounds. The reaction was proposed to

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• corresponding products in moderate to good yields. This reaction can tolerate a variety of functionalities, such as alkoxy, amino, ester, and nitro groups. However, a reaction temperature up to 100 °C and the requirement of excessive TMSCF3 (bp 55 °C) rendered the former reaction less than ideal. In 2012, the

• groups. This reaction can tolerate a variety of functionalities, such as alkoxy, amino and halide groups. The author proposed a plausible mechanism depicted in Scheme 42. At first, a dinitrogen ligated complex (N,N)CuX A is generated in situ by the reaction of CuI with phen. Then, a copper(I)-acetylide

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• excellent yields. However, to achieve high yields in this trifluoromethylation, one (or more) alkoxy group(s) must be present on the arenes in order to stabilise the free-radical intermediate (see mechanism in Scheme 47). Control experiments such as the trapping of the trifluoromethyl radical with the

Hydrolysis, polarity, and conformational impact of C-terminal partially fluorinated ethyl esters in peptide models

• Vladimir Kubyshkin and
• Nediljko Budisa

Beilstein J. Org. Chem. 2017, 13, 2442–2457, doi:10.3762/bjoc.13.241

• fragments decreases. The partially fluorinated ethoxy moieties reported here represent an intermediate situation between the partially fluorinated methoxy and propoxy/higher alkoxy groups (logP: CF3 > CHF2 ≈ CH3 > CH2F). Amide isomerism The tertiary amide bond in N-acylprolyl can exist in two conformational

• dielectric constant, as would be expected from an electrostatic interaction between the polar alkoxy group and the amide moiety (Figure 4). A somewhat similar situation has been recently reported by Siebler et al. for the C-terminal amide in dimethylamido N-acetylproline, where the conformational equilibrium

• function as an intramolecular probe of the C-terminal ester group polarity. Notably, the predicted flexibility of the partially fluorinated alkoxy groups in the presence of other strong dipoles is inconsistent with the concept of conformational adaptors elaborated by Müller et al. quite recently [44][65

Electron-deficient pyridinium salts/thiourea cooperative catalyzed O-glycosylation via activation of O-glycosyl trichloroacetimidate donors

• Mukta Shaw,
• Yogesh Kumar,
• Rima Thakur and
• Amit Kumar

Beilstein J. Org. Chem. 2017, 13, 2385–2395, doi:10.3762/bjoc.13.236

• presence of Schreiner′s thiourea in the reaction medium enhances the acidity of the ammonium salt due to doubling their dual hydrogen bonding ability with the carboxylate and the alkoxy group of the ammonium salt. A thiourea derivative also enhances the nucleophilicity of the glycosyl acceptor by imparting

• by the introduction of a cocatalyst such as an aryl thiourea derivative, which has the ability to form a dual hydrogen bond with the carboxylate and the alkoxy group of the ammonium salt [42][43][44]. To ensure our postulation, a 1H NMR spectroscopic study was carried out with a mixture of glycosyl

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• -photon absorbers (2PA). In this respect, the central DPP bicyclic lactam is often decorated with electron donors such as alkoxy- or dialkylamino groups [11][12], triphenylamine [13][14], heterocyclic carbazole [15], thiophene [16][17], furan [18], and organometallic ferrocene [19]. 2PA-active DPPs were

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• organic solvents is extremely high. Therefore, TFEO-Pcs can be easily purified by silica gel column chromatography. In addition, when a phthalocyanine is substituted with an electron-donating group, such as an alkoxy group, the electron density in the phthalocyanine macrocycle increases, making it easily

• iron phthalocyanine (TFEO-FePc) were compared with non-fluorinated alkoxy-substituted phthalocyanines [52]. A slightly bathochromic shift of the Q band was observed for TFEO-Pcs relative to non-fluorinated alkoxylated phthalocyanines. Although the melting points of non-fluorinated alkoxylated

• phthalocyanines are lower than 200 °C, TFEO-NiPc does not melt below 300 °C. Phthalocyanine iron complexes, which are substituted by non-fluorinated alkoxy groups at all peripheries, are easily oxidized and unstable, so these cannot even be synthesized. On the other hand, TFEO-FePc is stabilized by the strong

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• of Michael addition to acyclic nitrosoalkenes NSA4. Stereochemistry of Michael addition to γ-alkoxy nitrosoalkene NSA5. Oppolzer’s total synthesis of 3-methoxy-9β-estra(1,3,5(10))trien(11,17)dione (25). Oppolzer’s total synthesis of (+/−)-isocomene. Weinreb’s total synthesis of alstilobanines A, E

A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines

• Benedikt C. Melzer and
• Franz Bracher

Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156

• Benedikt C. Melzer Franz Bracher Department für Pharmazie - Zentrum für Pharmaforschung, Ludwig-Maximilians Universität München, Butenandtstr. 5-13, D-81377 Munich, Germany 10.3762/bjoc.13.156 Abstract Oxoisoaporphine alkaloids are conveniently prepared via direct ring metalation of alkoxy

• synthesis of oxoisoaporphines. By using our modification (1.5 equivalents of TMPMgCl∙LiCl over 4 h at room temperature) [13] of Knochel’s [23] protocol for the metalation of isoquinolines, the alkoxy-substituted isoquinolines 7a,b were metalated at C-1, as shown before, and this method could conveniently be

• direct ring metalation of alkoxy isoquinolines at C-1, followed by the reaction with iodine as central step. Subsequent Suzuki cross-coupling to methyl 2-(isoquinolin-1-yl)benzoates and intramolecular acylation with Eaton’s reagent afforded five alkaloids of the oxoisoaporphine type. Significant

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• difficult and elaborate. Most of these, including the most frequently used α-alkoxy derivatives (Z = OR), N-[1-(benzotriazol-1-yl)alkyl]amides (Z = 1-benzotriazolyl) and 1-(N-acylamino)alkyl sulfones (Z = SO2Ar) require activation with Lewis acids, which are expensive (e.g., ZrCl4, VCl3, CeCl3, Bi(OTf)3 or

• aromatic systems with strong electron-donating substituents (e.g., alkoxy-, polyalkoxy- and aminoarenes), or some activated heterocyclic systems such as indole [3][8][10][24][25]. The α-imidoalkylation reaction using N-(1-hydroxyalkyl)imides (almost entirely N-hydroxymethylphthalimide) in sulfuric acid

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

• to a mixture of 1,2-dihydroisoquinolines 236 and substituted 1-indanone derivatives 237 via alkoxy group migration in 16 and 57% yields, respectively (Scheme 66) [95]. 2 Construction of the 6-membered ring The titles of subsections in this chapter contain names of the 1-indanone precursors which

Iodination of carbohydrate-derived 1,2-oxazines to enantiopure 5-iodo-3,6-dihydro-2H-1,2-oxazines and subsequent palladium-catalyzed cross-coupling reactions

• Michal Medvecký,
• Igor Linder,
• Luise Schefzig,
• Hans-Ulrich Reissig and
• Reinhold Zimmer

Beilstein J. Org. Chem. 2016, 12, 2898–2905, doi:10.3762/bjoc.12.289

• -alkoxy-γ-amino-aldehydes and ketones [14]. In this context, a series of publications of our group reported on syntheses of carbohydrate mimetics [15][16][17][18][19][20] that are based on aminopyrans, aminooxepanes or other aminopolyols and that were examined for example as ligands of L- and P-selectin

• ], although the direct β-iodination of enol ethers using a suitable electrophilic iodine reagent is relatively underdeveloped. For the iodination of 4-alkoxy-3,6-dihydro-1,2-oxazines 3, we selected molecular iodine as the most simple iodination reagent in the presence of a base [28][29][30]. A clean reaction

Symmetry-based approach to oligostilbenoids: Rapid entry to viniferifuran, shoreaphenol, malibatol A, and diptoindonesin G

• Youngeun Jung,
• Dileep Kumar Singh and
• Ikyon Kim

Beilstein J. Org. Chem. 2016, 12, 2689–2693, doi:10.3762/bjoc.12.266

• natural oligostilbenoids guided us to design a modular synthetic approach to these molecules by utilizing a three-step sequence consisting of Sonogashira coupling, iodocyclization, and Suzuki coupling. During our synthesis, the relative reactivities of ester, aldehyde, and alkoxy groups on the same aryl

• , 2, and 3) were readily available from the corresponding C2 symmetric precursors via monoiodination, we decided to evaluate this route. In particular, we wondered what functional group as a G moiety would be appropriate for the successful iodine-mediated cyclization. Ester, aldehyde, and alkoxy

• product which decomposed eventually. On the other hand, 6 was successfully converted to the desired 3-iodobenzofuran 11 in good yield. These results led us conclude that either ester or aldehyde groups perform as better nucleophiles than an alkoxy group in the iodocyclization. Having secured gram

Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: synthesis, characterization and highly selective sensor for Cu²⁺

• Rahman Hosseinzadeh,
• Mohammad Nemati,
• Reza Zadmard and
• Maryam Mohadjerani

Beilstein J. Org. Chem. 2016, 12, 1749–1757, doi:10.3762/bjoc.12.163

• ]arene bearing anthraceneisoxazolymethyl [3], quinolone [28], 5-nitrosalicylaldehyde [29], 3-alkoxy-2-naphthoic acid [30], coumarine [31] and benzothiazole [10][15] groups. In continuation of our studies on developing novel chemosensors containing fluorenyl moieties as fluorogenic group [32][33][34], we

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

• a good leaving group. The Criegee rearrangement was discovered in 1944 in the reaction of decaline ethylperoxoate 127 that rearranged into isomeric ester ketal 128 (Scheme 39) [291]. The mechanism of the Criegee rearrangement was studied using 2-alkoxy-2-propyl per-4-nitrobenzoates [292]. It was

• -oxabicycloalkanes 147a–d in formic or acetic acid containing catalytic amounts of sulfuric acid affords ω-alkoxy-(ω-3)-hydroxyalkanoic acid lactones 148a–d and 149a–d (Table 10) [297]. The transformation of 1-hydroperoxy-2-oxabicycloalkanones 147a–d into ω-alkoxy-(ω-3)-hydroxyalkanoic acid lactones 148a–d and 149a

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

• Roman Yu. Peshkov,
• Elena V. Panteleeva,
• Wang Chunyan,
• Evgeny V. Tretyakov and
• Vitalij D. Shteingarts

Beilstein J. Org. Chem. 2016, 12, 1577–1584, doi:10.3762/bjoc.12.153

• -coupling; cyanoarenes; reactive intermediates; reductive alkylation; Introduction Alkylcyanobiphenyls are well known largely due to their mesogenic properties, which were discovered by Gray in the 1970th [1][2]. Alkylcyanobiphenyls and their analogs (e.g., dialkyl and alkoxy alkyl derivatives) are still

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals

• Sonia L. Repetto,
• James F. Costello,
• Craig P. Butts,
• Joseph K. W. Lam and
• Norman M. Ratcliffe

Beilstein J. Org. Chem. 2016, 12, 1467–1475, doi:10.3762/bjoc.12.143

• impact of substituents upon the formation [10][11][19][20][21][22] and reactivity of charged intermediates [14] have all attracted scrutiny. A generic 2-alkoxy-2-alkyl-1,3-dioxolane A is used to illustrate the generally accepted specific acid-catalysed three-stage hydrolysis mechanism of orthoesters

• , initially undergo exclusive cleavage of the exocyclic alkoxy group [19]. In reviewing the case of orthoesters, Kresge et al. suggests two mechanistic extremes [19][24]. A concerted catalysed process, wherein the –OR group undergoes protonation as the C···O(H+)R bond begins to undergo cleavage. The

On the mechanism of imine elimination from Fischer tungsten carbene complexes

• Philipp Veit,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2016, 12, 1322–1333, doi:10.3762/bjoc.12.125

• complexes [16][17]. First representatives of multimetal carbene complexes M(CO)5(1R) bear α-ferrocenyl alkoxy carbenes :C(OR)Fc (1R, M = Cr, Mo, W; R = Me, Et; Fc = ferrocenyl) [18][19][20][21][22]. Nucleophilic substitution of the alkoxy substituent OR by amines gives access to α-ferrocenylamino Fischer

• -donating character of the amino substituent vs the alkoxy substituent thus increasing the C(carbene)–X double bond character (X = N, O) [62][63][64] and the loss of some attractive NH…Fe interaction (H…Fe(Fc-C) = 2.98 Å) in W(CO)5(E-2) [27][54][55][56][57][58][59]. The Gibbs free energy of activation for

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• successfully used trialkyl orthoformates 13 to produce dialkyl (2-oxo-4-(trifluoromethyl)-1,2-dihydropyrimidin-5-yl)phosphonates 14 which were converted to dialkyl (4-alkoxy-2-oxo-4-(trifluoromethyl)-1,2,3,4-tetrahydropyrimidin-5-yl)phosphonates 15 through the nucleophilic addition of the liberated alcohol to

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• carboxylic acids [33][34][35][36][37][38][39][40]. These components form α-alkoxy-substituted β-ketoenamides as precursors of highly substituted pyridine derivatives. We therefore tried to independently prepare β-ketoenamides with this substitution pattern starting from simple 1,3-diketones such as 1a. An

• related reaction conditions [41][42][43][44][45]. In this context we want to notice that our approach to alkoxy-substituted β-ketoenamides via alkoxyallenes also allowed the synthesis of 5-acetyloxazoles with high flexibility, if the acid-labile trimethylsilylethyl group was introduced via the

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• atmospheric chemists to undertake physicochemical analysis of important climate related IPNs. In the atmosphere isoprene (1) has a half-life of ~1−2 hours [16]. It reacts readily with HO• and O2 generating alkoxy radical (RO•) intermediates (not shown) as well as hydroperoxy radicals (ROO•) such as rac-2 and

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• ; only anilides possessing a strongly donating alkoxy group meta to the directing group (para to the position where the C–H activation would occur) were reactive. However, we have since found that use of acetonitrile-free, in situ generated cationic palladium with arylureas as the directing group