Synthesis and spectroscopic properties of 4-amino-1,8-naphthalimide derivatives involving the carboxylic group: a new molecular probe for ZnO nanoparticles with unusual fluorescence features

• Laura Bekere,
• David Gachet,
• Vladimir Lokshin,
• Wladimir Marine and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2013, 9, 1311–1318, doi:10.3762/bjoc.9.147

• . Photophysical properties The spectroscopic properties of 1,8-naphthalimides are strongly dependent on the substituent at C-4 of the naphthalene ring. In general, the derivatives with a halogen atom or alkoxy groups are colorless and exhibit blue fluorecence [15][16], while the amino-substituted 1,8

Copper-catalyzed aerobic aliphatic C–H oxygenation with hydroperoxides

• Pei Chui Too,
• Ya Lin Tnay and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2013, 9, 1217–1225, doi:10.3762/bjoc.9.138

• 3% yields, respectively, via the desired 1,4-dioxygenation, while benzophenone (7b) was also formed in 30% yield through fragmentation of the transient alkoxy radical (Scheme 4). Use of 40 mol % of NHPI slightly improved the yields of 1,4-dioxygenation products 2i and 3i (40% and 4% yields

Substituent effect on the energy barrier for σ-bond formation from π-single-bonded species, singlet 2,2-dialkoxycyclopentane-1,3-diyls

• Jianhuai Ye,
• Yoshihisa Fujiwara and
• Manabu Abe

Beilstein J. Org. Chem. 2013, 9, 925–933, doi:10.3762/bjoc.9.106

• categorized as Type-1 diradicals [1][27], which possess a π-single-bonding character (–π–, closed-shell character) between the two radical sites. The role of the alkoxy group (OR) on the lifetime (k = 1/τ) was investigated by combined studies of experiments and quantum chemical calculations [26][28]. The

• steric repulsion between the alkoxy group and the phenyl ring, which is indicated in the transition-state structure for the ring-closing reaction (Scheme 1), was found to play an important role in determining the energy barrier of the ring-closing process, τ293 = 292 ns (DRa: OR = OCH3, λmax = 574 nm

• . Localized singlet diradicals. (a) Absorption spectrum of the singlet diradical DRe in a MTHF matrix at 80 K; (b) transient absorption spectrum of AZe measured immediately after the laser pulse (λexc = 355 nm); (c) transient decay trace at 580 nm and 20 °C. Alkoxy group effect on the lifetime of π-single

Diastereoselective synthesis of nitroso acetals from (S,E)-γ-aminated nitroalkenes via multicomponent [4 + 2]/[3 + 2] cycloadditions promoted by LiCl or LiClO₄

• Leandro Lara de Carvalho,
• Robert Alan Burrow and
• Vera Lúcia Patrocinio Pereira

Beilstein J. Org. Chem. 2013, 9, 838–845, doi:10.3762/bjoc.9.96

• tendency to the pseudoaxial orientation of the alkoxy group in nitroso acetals is associated with a stabilization generated by an anomeric effect [1][36]. The protons (H6) and (H4) were both irradiated in 2D NOESY experiments and a cis relationship between them was achieved for all cycloadducts. When the

• [3 + 2] cycloadditions, we believe that in the TS the respective nitronates present a half-chair conformation with the HC(4) substituent and the alkoxy group in an axial position to maximize the stabilization generated by the anomeric effect [9][33][41][42]. Thus, the competitive endo/exo approach of

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• process; it also quenches the intermediate alkoxy radical, liberating concomitantly an ethyl radical to propagate the chain. Except in the cleavage of epoxides, homolytic rupture of carbon–oxygen bonds is generally a difficult process. Radicals can thus be generated next to alcohols or esters without fear

Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

• Alexej Bubnov,
• Miroslav Kašpar,
• Věra Hamplová,
• Ute Dawin and
• Frank Giesselmann

Beilstein J. Org. Chem. 2013, 9, 425–436, doi:10.3762/bjoc.9.45

• observed for the chiral compound in [26] having the same molecular core as TL4 but a branched chiral alkoxy chain instead of the decyloxy group used for TL4. The relation between the molecular structure and mesomorphic properties of these new multifunctional compounds with different structures is discussed

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Radical zinc-atom-transfer-based carbozincation of haloalkynes with dialkylzincs

• Fabrice Chemla,
• Florian Dulong,
• Franck Ferreira and
• Alejandro Pérez-Luna

Beilstein J. Org. Chem. 2013, 9, 236–245, doi:10.3762/bjoc.9.28

• plausible explanation for the fact that bromine substitution occurs from α-oxgenated bromoalkyne 11 and not from 9. Regarding our 1,4 addition/carbocyclization sequence, these test experiments provide two important pieces of evidence for the behavior of 3a in the presence of a dialkylzinc. First, β-alkoxy

A new family of four-ring bent-core nematic liquid crystals with highly polar transverse and end groups

• Kalpana Upadhyaya,
• Venkatesh Gude,
• Golam Mohiuddin and
• Rao V. S. Nandiraju

Beilstein J. Org. Chem. 2013, 9, 26–35, doi:10.3762/bjoc.9.4

• , i.e.., chloro in the bent or transverse direction in the central core and cyano in the lateral direction at one terminal end of the molecule, are designed and synthesized. These molecules possess an alkoxy chain attached at only one end of the bent-core molecule. The molecular structure

• Discussion Synthesis and characterization Here we adopted a very simple and straightforward synthetic methodology for the synthesis of these materials exhibiting a nematic phase. The non-symmetric four-ring molecules possess an alkoxy chain attached at only one end of the bent-core molecule, while the other

Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

• Yan Sun,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 8–14, doi:10.3762/bjoc.9.2

• Table 1. From these results we could see that only anilines with electron-donating alkyl and alkoxy groups reacted smoothly. When anilines with electron-withdrawing p-chloro, p-bromo, m-nitro, or p-nitro groups were used in this three-component reaction, no expected spiro[dihydropyridine-oxindole] could

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

Recent advances towards azobenzene-based light-driven real-time information-transmitting materials

• Jaume García-Amorós and
• Dolores Velasco

Beilstein J. Org. Chem. 2012, 8, 1003–1017, doi:10.3762/bjoc.8.113

• -azobenzene derivatives. This notable red-shift of the absorption wavelength arises from the strong charge transfer from the alkoxy group to the positively-charged nitrogen atom of the pyridinium salt. Figure 8 shows the transient absorption generated upon pulsed laser irradiation of ethanol solutions of azo

• electron transfer from the alkoxy group to the pyridinium salt produces a partial breaking of the double N–N bond of the azo moiety, thereby facilitating the rotation around this bond to recover the more stable initial trans configuration in a quick fashion [56]. Type-II azoderivatives: photochromic

• the alkoxy- and hydroxy-substituted azo-dyes reflect that some alteration in their intimate isomerisation mechanism occurs. The rapid thermal cis-to-trans isomerisation of the hydroxy-substituted azo-dyes suggests that their back reaction takes place via the rotational pathway, through a polar

Synthesis of oleophilic electron-rich phenylhydrazines

• Aleksandra Jankowiak and
• Piotr Kaszyński

Beilstein J. Org. Chem. 2012, 8, 275–282, doi:10.3762/bjoc.8.29

• alkyl, alkoxy or alkylsulfanyl groups were successfully prepared by acid-induced removal of the Boc group in hydrazides 2. The reaction is carried out with 5 equivalents of TfOH in CF3CH2OH/CH2Cl2 at −40 °C for 1.5 min. Under these conditions, the deprotected hydrazine 1 is fully protonated, which

• , alkoxy and alkylsulfanyl groups. Here we demonstrate an efficient method for the preparation of several hydrophobic di- and tri-substituted phenylhydrazines in purities sufficient for further chemical transformations. Finally, we demonstrate the application of one of the phenylhydrazines for the

• ± 0.01 eV. Conclusion We have developed a synthetic protocol for the efficient preparation of electron-rich phenylhydrazines 1 substituted with alkylsulfanyl, alkyl and alkoxy groups from Boc hydrazides 2. Experiments demonstrate that the addition of hydrazides 2 to a large excess of TfOH (5 equiv) at

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• ][81], push–pull amines and betaines 74–78 [82][83][84][85][86][87], alkoxy derivatives 79,80 [88], biimidazoles 81 [89][90][91][92], and triimidazoles 82 [93][94], as well as fullerenes [95] and polymers [96][97][98][99]. The chemistry of 4,5-dicyanoimidazole was reviewed in 1987 by Donald and Webster

Synthesis of 2-amino-3-arylpropan-1-ols and 1-(2,3-diaminopropyl)-1,2,3-triazoles and evaluation of their antimalarial activity

• Matthias D’hooghe,
• Stéphanie Vandekerckhove,
• Karen Mollet,
• Karel Vervisch,
• Stijn Dekeukeleire,
• Liesbeth Lehoucq,
• Carmen Lategan,
• Peter J. Smith,
• Kelly Chibale and
• Norbert De Kimpe

Beilstein J. Org. Chem. 2011, 7, 1745–1752, doi:10.3762/bjoc.7.205

• efforts have been devoted to the preparation of structurally diverse analogues bearing a functionalized propane skeleton [6][7][8]. In that respect, we have been engaged in the stereoselective synthesis of syn-2-alkoxy-3-amino-3-arylpropan-1-ols 1 by reductive ring opening of the corresponding β-lactams

Structural conditions required for the bridge lithiation and substitution of a basic calix[4]arene

• Conrad Fischer,
• Wilhelm Seichter and
• Edwin Weber

Beilstein J. Org. Chem. 2011, 7, 1602–1608, doi:10.3762/bjoc.7.188

• the lower-rim site as well as tert-butylated or non-tert-butylated upper-rim positions. Whereas this reaction fails for symmetric calix[4]arene ethers with alkoxy residues greater than methoxy, the carboxylation of mixed methoxy-propoxy calixarene ethers is possible. In connection with this, several

Cyclization of 5-hexynoic acid to 3-alkoxy-2-cyclohexenones

• Anne T. Hylden,
• Eric J. Uzelac,
• Zeljko Ostojic,
• Ting-Ting Wu,
• Keely L. Sacry,
• Krista L. Sacry,
• Lin Xi and
• T. Nicholas Jones

Beilstein J. Org. Chem. 2011, 7, 1323–1326, doi:10.3762/bjoc.7.155

• -alkoxy-2-cyclohexenones proceeds in good yields (58–90%). 3-Hexynoic acid was converted to its acyl chloride with the aid of oxalyl chloride and was cyclized to 3-chloro-2-cyclohexenone upon addition of indium(III) chloride. Subsequent addition of alcohol nucleophiles led to the desired 3-alkoxy-2

• -cyclohexenones. Keywords: acyl chlorides; alcohols; alkynes; cyclization; Lewis acids; Findings Synthetic applications of 3-alkoxy-2-cyclohexenones toward the pursuit of natural products have been well documented [1][2][3][4]. Traditionally, 3-alkoxy-2-cyclohexenones have been prepared from 1,3-cyclohexadiones

• under a variety of conditions [5][6]. We report herein the cyclization of 5-hexynoyl chloride (2) as a complementary approach to the synthesis of 3-alkoxy-2-cyclohexenones 1 (Scheme 1). The carbocyclization of 5-hexynoic acid was first reported by Tedder in 1957 [7]. Treatment of 5-hexynoic acid with

Combined directed ortho-zincation and palladium-catalyzed strategies: Synthesis of 4,n-dimethoxy-substituted benzo[b]furans

• Verónica Guilarte,
• M. Pilar Castroviejo,
• Estela Álvarez and
• Roberto Sanz

Beilstein J. Org. Chem. 2011, 7, 1255–1260, doi:10.3762/bjoc.7.146

• compound [22][23]. In particular, several benzo[b]furan derivatives with oxygen-bearing substituents, such as hydroxy, or alkoxy, at the benzene moiety are known to be biologically active compounds [24][25][26][27][28] (Figure 1). Among the various approaches developed for the synthesis of the benzofuran

Recent developments in gold-catalyzed cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124

• external vinyl ether 4, leading to interesting 9-oxabicyclo[3.3.1]nona-4,7-dienes 5 in good yields (Scheme 2). In view of the highly stereoselective outcome of these reactions and the requirement of an alkoxy or acyloxy group at the propargylic position of 3, the authors proposed a reaction pathway based

• oxacyclic product 5. Importantly, the reaction also proceeds with non-aromatic 1-oxo-4-alkoxy-5-ynes [40]. Curiously, when the substrate features an internal alkyne, such as in alkynyl acetate 6, the reaction evolves through alternative mechanistic pathways [41]. In particular, Liu showed that in these

• reactions have been reported in recent years (Scheme 17) [70][71]. Finally, the activation of alkynes with Au(I) has also been used recently to induce a hetero-dehydro Diels–Alder type of reaction. In particular, certain dienynes 29 with alkoxy groups at position 1 undergo a (4 + 2) cycloaddition with

A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

• Christian Eidamshaus,
• Roopender Kumar,
• Mrinal K. Bera and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2011, 7, 962–975, doi:10.3762/bjoc.7.108

• procedures, we decided to purify the reaction mixture at the stage of the β-alkoxy-β-ketoenamides 58 obtained by the three-component reaction. Recently we demonstrated that β-alkoxy-β-ketoenamides are not only valuable intermediates in the synthesis of 4-hydroxypyridines 57, but that they can also serve as

• precursors in the synthesis of 5-alkoxypyrimidines 59 (Scheme 6). When β-alkoxy-β-ketoenamides 58 were treated with an ammonia source such as NH4OAc in MeOH, 5-alkoxypyrimidines with the general structure of 59 were formed in high yields [37][38][47]. By this simple change in the reaction conditions not only

• chemicals were used without further purification unless otherwise stated. Typical procedure for the preparation of 3-methoxy-4-hydroxypyridines without isolation of the intermediate β-alkoxy-β-ketoenamide (Procedure 1) A solution of n-BuLi (2.5 M in hexanes, 0.31 mL, 0.79 mmol) was added dropwise to a

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• benzannulation of 3-alkoxy-1,5-enynes 236 to produce functionalized benzenes 237 [112]. The reaction occurs selectively through a 6-endo-dig pathway to give tri- and tetrasubstituted benzenes efficiently. Cyclization reactions of 1,6-diynes (2,2-dipropargylmalonates 238) could be achieved with gold(I) catalysts

Gold-catalyzed oxidation of arylallenes: Synthesis of quinoxalines and benzimidazoles

• Dong-Mei Cui,
• Dan-Wen Zhuang,
• Ying Chen and
• Chen Zhang

Beilstein J. Org. Chem. 2011, 7, 860–865, doi:10.3762/bjoc.7.98

• . Phenylallene gave a good isolated yield of 1-phenylpropan-1,2-dione (2c) and benzaldehyde (3c) in a ratio of 43:57 (Table 2, entry 3). With a more electron-donating alkoxy group, the expected products were again obtained in good yields (Table 2, entry 4). In addition, oxidation of arylallene with an electron

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

• ). Nitrones also reacted as dipolarophiles in the presence of AuCl3, even if in some cases copper catalysts were found to be more effective at triggering the corresponding annulations [52]. By contrast, when alkoxy vinyl ethers were employed as dipolarophiles, the cycloaddition takes place prior to the

• formation of the 1,4-furan dipole (Scheme 21). In fact, a resonance structure of 60 can be envisaged entailing a gold–carbene and a carbonyl ylide 63. Upon 1,3-dipolar cycloaddition with the alkoxy vinyl ether, bridged bicycle 64 is formed. 1,2-Alkyl migration and bridge opening produces a spiro cation 66

Synthesis, reactivity and biological activity of 5-alkoxymethyluracil analogues

• Lucie Brulikova and
• Jan Hlavac

Beilstein J. Org. Chem. 2011, 7, 678–698, doi:10.3762/bjoc.7.80

• . Synthesis Synthesis of alkoxy-haloalkyl derivatives The most numerous and also the most investigated group of the above mentioned derivatives is a group of alkoxy-haloalkyl compounds derived either from uracil or nucleosides (Figure 2). With regard to the high variability of sugar moiety, the description of

• -(1-methoxy-2-iodoethyl) nucleosides, Kumar and co-workers also reported the synthesis of other alkoxy derivatives – 5-(1-alkoxy-2-iodoethyl) and 5-(1-ethoxy-2,2-diiodoethyl)-2'-deoxyuridine analogues 33–36 (Scheme 5) [11]. The reaction of (E)-5-(2-iodovinyl) 32 and 5-vinyl-2'-deoxyuridine (9) with

• iodine monochloride and alcohols such as ethanol, 2-fluoroethanol or 2,2,2-trifluoroethanol afforded 5-(1-ethoxy-2,2-diiodoethyl) 33 and 5-(1-alkoxy-2-iodoethyl)-2'-deoxyuridines 34–36, in 33–90% yields. All of these four products 33–36 were obtained as a mixture of two diastereomers in a 1:1 ratio. In

A gold-catalyzed alkyne-diol cycloisomerization for the synthesis of oxygenated 5,5-spiroketals

• Sami F. Tlais and
• Gregory B. Dudley

Beilstein J. Org. Chem. 2011, 7, 570–577, doi:10.3762/bjoc.7.66

• dehydration to furan 10. The use of alkyne-diol cycloisomerization instead of ketone-diol cyclocondensation is important for the potential success of this approach, since β-alkoxy ketone 9 (Scheme 4, inset) would be more prone to undesired elimination than homopropargyl ether 6. We addressed regiochemistry by