Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

• Marcin Kaźmierczak and
• Henryk Koroniak

Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69

• -dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDCl) [41] significantly increased the reaction yield (86%). What is more, the reaction byproduct is water-soluble and easy to remove by extraction. Nevertheless, HOBt was still used as an additive. This reagent has recently been reported to exhibit explosive

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• their water solubility; that is the sulfobutyl group in the case of R1 or -SO3− in the case of either R2 or R3. Water soluble cyanines could feasibly favor physical drying of aqueous dispersions upon irradiation with a NIR-LED [70]. In addition, chemical drying of coatings requires the use of strong

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• was very low after trapping 75 with diphenylchlorophosphine [79]. The PTA motif is water soluble, thermally, air and moisture stable. The PTA building block can be synthesized by coupling tris(hydroxymethyl)phosphine (73) with formaldehyde and ammonia in ice water or with hexamethylenetetramine. A

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives

• David Martínez-López,
• Amirhossein Babalhavaeji,
• Diego Sampedro and
• G. Andrew Woolley

Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296

• neutral pH, creating a doubly charged species. As anticipated, compound 5 was found to be much more water-soluble than 4. The UV–vis spectrum of 5 at a neutral pH value is shown in Figure 4. Irradiation with blue light at 440 nm produced the PSS (dotted line). Thermal reversion from the cis isomer was

Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications

• Daria V. Berdnikova

Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275

• photochemical properties. Along these lines, special efforts have been devoted to design, for example, water-soluble derivatives of spiropyran [1][2][3], azobenzene [4][5], diarylethene [6][7][8], or chromene [9] that keep efficient photochromism in aqueous medium. Although a significant progress has been made

• in the development of water-soluble photochromes, there is still an emerging search for new types of photochromic compounds for applications in biological systems. In particular, nowadays the development of photopharmacology is based mainly on azobenzene chemistry [10][11] and, therefore, finding of

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• a water-soluble molecule which has a high affinity and selectivity for calcium, allowing binding of physiological levels of calcium, whose binding can be switched reversibly as efficiently as possible both in terms of affinity and quantum yield. In principle this would offer real-time regulation of

Iodine-mediated hydration of alkynes on keto-functionalized scaffolds: mechanistic insight and the regiospecific hydration of internal alkynes

• Zachary Lee,
• Brandon R. Jones,
• Nyochembeng Nkengbeza,
• Michael Phillips,
• Kayla Valentine,
• Alexis Stewart,
• Brandon Sellers,
• Nicholas Shuber and
• Karelle S. Aiken

Beilstein J. Org. Chem. 2019, 15, 2747–2752, doi:10.3762/bjoc.15.265

• innocuous, water-soluble byproducts, such as iodide and sulfate salts, and uses inexpensive molecular iodine to facilitate the hydration. Moreover, unlike other metal-free alkyne hydration procedures, heat and strong acids are not required [17][18][19][20]. The reaction proceeds under mild conditions at

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• application of water-soluble plasma membrane probes [17][18]. We have been developing a new class of selective bioprobes based on the derivatization of the 2,1,3-benzothiadiazole (BTD) core (Figure 1) [19][20][21][22]. After we disclosed the use of these BTD derivatives as a new class of selective

• the design, synthesis, properties and application of a new fluorogenic BTD derivative as a water-soluble selective plasma membrane probe for bioimaging experiments. Results and Discussion The new water-soluble fluorescent BTD derivative (named BTD-4APTEG) was planned and synthesized as shown in Scheme

• better conjugation with the 4AP substituent at the C4 carbon of the BTD heterocyclic core. The ionic nature of the structure in combination with a hydrophilic anion (MeSO3−, methanesulfonate) and the presence of the hydrophilic domain (triethylene glycol monomethyl ether) make the dye a water-soluble BTD

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• a premade complex of 2 with a tightly bound guest, tetra-o-fluoroazobenzene [49], no acceleration effect was observed. Conclusion In summary, we investigated the encapsulation and switching of a prototypical arylazopyrazole in the hydrophobic cavity of a water-soluble metal–organic cage. A host

Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

• Anne-Marie Caminade,
• Artem Zibarov,
• Eduardo Cueto Diaz,
• Aurélien Hameau,
• Maxime Klausen,
• Kathleen Moineau-Chane Ching,
• Jean-Pierre Majoral,
• Jean-Baptiste Verlhac,
• Olivier Mongin and
• Mireille Blanchard-Desce

Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221

• water-soluble dumbbell-like dendrimers retains a similar TPA response as that of the model monomer in ethanol, as shown by σ2 values of 104 GM for G1, 119 for G2, and 127 for G3, in water [56]. The same type of synthetic method was applied to another TPA fluorophore functionalized by two phenols, but

• confinement in the double layer dendrimer has a detrimental influence on the TPA properties [63]. Biological properties of dendrimers having TPA properties Most of the water-soluble fluorescent dendrimers shown in the previous paragraphs have been synthesized for diverse biological purposes. The first type of

• high antiproliferative activities against different tumor cell lines. A fluorescent water-soluble dendrimer, applicable for two-photon photodynamic therapy and imaging. Schematization of the different types of TPA fluorescent phosphorus dendrimers and dendritic structures that have been already

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• effect on stability and ordering, and, additionally we aimed to test the possibility of formation of water-soluble capsules, which are of particular interest to supramolecular chemists. Results and Discussion RSAs can be readily synthesized by the Mannich reaction of upper-rim unsubstituted resorcin[4

• ]arenes with sodium sulfite and formaldehyde according to a general synthetic procedure [15]. While the synthetic procedure for water soluble RSAs is straightforward, purification of the final products is tricky and highly substrate-dependent. RSA 1 was obtained in 92% yield after purification involving

Design, synthesis and biological evaluation of immunostimulating mannosylated desmuramyl peptides

• Rosana Ribić,
• Ranko Stojković,
• Lidija Milković,
• Mariastefania Antica,
• Marko Cigler and
• Srđanka Tomić

Beilstein J. Org. Chem. 2019, 15, 1805–1814, doi:10.3762/bjoc.15.174

• significant role in the stimulation of the immune response. In particular, compound 21 was identified, so far, as the most potent adjuvant in this class of mannosylated desmuramyl peptides. It should be also noted that the compound 21 is stable, non-pyrogenic and water-soluble what makes it potentially

Host–guest interactions in nor-seco-cucurbit[10]uril: novel guest-dependent molecular recognition and stereoisomerism

• Xiaodong Zhang,
• Wei Wu,
• Zhu Tao and
• Xin-Long Ni

Beilstein J. Org. Chem. 2019, 15, 1705–1711, doi:10.3762/bjoc.15.166

• [18][19][20][21][22]. However, forming ternary complexes with Q[8] is challenging because the number of aromatic-derived water-soluble recognition motifs remains limited. In 2006, Isaacs and co-workers reported the synthesis and isolation of nor-seco-cucurbit[10]uril (NS-CB[10], host-1, Scheme 1) [23

2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes

• Li-Li Wang,
• Yi-Kuan Tu,
• Huan Yao and
• Wei Jiang

Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146

• tetralactam macrocycles [14][15][16]. The Smith group has used tetralactam macrocycles to encapsulate and stabilize deep-red fluorescent squaraine dyes for biomedical applications [17][18][19][20]. By introducing water-soluble groups to tetralactam macrocycles, Davis and co-workers realized selective

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• by dynamic light scattering. Light-responsive end-to-end assembly of host-functionalized gold nanorods (AuNR) by cyclodextrin–AAP interaction. Two-step ligand exchange reaction for the synthesis of water-soluble cyclodextrin end-functionalized gold nanorods. Supporting Information Supporting

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• supramolecular cavities [25]. Calixarenes are the third generation of macrocyclic compounds composed of phenolic units bridged with methylene groups at the o-positions of phenolic hydroxy groups [9]. We have focused on molecular recognition and self-assembly of water-soluble calixarene derivatives for a long

• materials and constructing dye-sensitized solar cells. Results and Discussion GC5A was prepared according to our previous procedure and represents a robust water-soluble macrocyclic receptor [26]. According to the positively charged feature of GC5A, a series of negatively charged dyes, including Fl, eosin Y

Host–guest interactions between p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene and group IA, IIA and f-block metal cations: a DFT/SMD study

• Valya K. Nikolova,
• Cristina V. Kirkova,
• Silvia E. Angelova and
• Todor M. Dudev

Beilstein J. Org. Chem. 2019, 15, 1321–1330, doi:10.3762/bjoc.15.131

• .15.131 Abstract The molecular recognition in aqueous solution is extremely important because most biological processes occur in aqueous solution. Water-soluble members of the calix[n]arene family (e.g., p-sulfonato substituted) can serve as model systems for studying the nature and manner of interactions

• between biological receptors and small ions. The complex formation behavior of water-soluble p-sulfonatocalix[4]arene and thiacalix[4]arene and group IA, IIA and f-block metal cations has been investigated computationally by means of density functional theory computations in the gas phase and in aqueous

• biological activity of the calix[n]arenes on various life forms from viruses to human beings have been reported [22]. The first water-soluble calix[n]arene derivative, p-tert-butylcalix[4]arenetetracarboxylic acid, was synthesized in 1984 [23]. The first paper on the calixarenes having sulfonate groups (and

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

• water-soluble crown macrocycle 3 was synthesized according to reported protocols, by using potassium cations as template [86][87]. The primary amine group in 3 offers diverse reaction pathways to design crown ethers appended LMW gelators, dendrimers and polymers [88][89][90][91][92]. In order to

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• crystal structures of acene and azaacene guests inside tetralactam B with the surrounding macrocycle in chair or boat conformations [25]. Recent work has shown that water-soluble versions of anthracene tetralactam B can be threaded by water soluble squaraine dyes with very high affinities (Ka ≈ 109 M−1

• water is due primarily to a highly favorable enthalpic change [61]. Furthermore, tetralactam threading studies using water-soluble squaraine guests with flanking benzylic groups have produced Ka values that were close to 1011 M−1 [62]. The affinity gain is due to a guest back-folding effect where the

• shown that members of this tetralactam family are effective receptors for saccharides in water [65]. As shown by the X-ray crystal structure in Figure 7a, water-soluble versions of tetralactam B can nicely accommodate β-glucopyranose within the cavity [66]. There is a combination of hydrogen bonding

Easy, efficient and versatile one-pot synthesis of Janus-type-substituted fullerenols

• Marius Kunkel and
• Sebastian Polarz

Beilstein J. Org. Chem. 2019, 15, 901–905, doi:10.3762/bjoc.15.87

• making it possible to obtain water soluble fullerenols as well as fullerenols that are still soluble in organic solvents [15][16][17][18][19]. The maximum number of OH groups, which could be attached to C60 is n = 44 [17]. Further derivatizations, where all hydroxy moieties of the compound have been

• simultaneously by using a common phase transfer reaction which enables even the combination of water-soluble substituents with the precursor C60Cl6. High yields of Janus-fullerenol derivatives bearing five defined substituents on one pole of the C60 core combined with in average 19 (+/−3) oxygen containing

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• being more deshielded (Δδ ≈ 0.026 ppm) than the others (Supporting Information File 1, Figure S14). The 6A,6B-regioisomer is also the least water-soluble. Consequently, structural verification was solely based upon the analysis of the ditosyl precursors, as discussed above. Hetero-difunctionalized β

Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

• of the deacetylated (water-soluble) sugars, the performance of the sugars in MGE, and the assessment of their metabolic acceptance. The studies uncovered that Ac4ManNCp is much better accepted than Ac4ManNCyoc although their membrane staining intensity after MGE is comparable. The high metabolic

• constant k2 of ManNCyoc has previously been reported to be k2 = 0.99 M−1s−1 [24]. To determine k2 of Cyc- and Cp-modified mannosamine, we synthesized ManNCyc and ManNCp according to published protocols [23][27], omitting the final peracetylation step. In this way, water-soluble compounds were obtained that

• allowed the determination of rate constants in aqueous solution. As reported for ManNCyoc, an excess of ManNCyc and ManNCp, respectively, was reacted with water-soluble tetrazine Tz-PEG-OH in acetate buffer (pH 4.7, Figure 2A). The decrease of absorption of Tz-PEG-OH at λmax = 522 nm was measured and

A chemoenzymatic synthesis of ceramide trafficking inhibitor HPA-12

• Seema V. Kanojia,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2019, 15, 490–496, doi:10.3762/bjoc.15.42

• environment damaging organic solvent, but also increase the reaction rate, and provide many other technological advantages [49]. Towards this, we have chosen [bmim][BF4] and [bmim][PF6] as two model ionic liquids. Of them, [bmim][BF4] is water soluble, and [bmim][PF6] is immiscible with water. The acetylation

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• some of the most representative catalysts developed for aqueous metathesis. Water-soluble catalysts are obtained by derivatization of classical catalysts G-II and HG-II (Figure 1a), resulting from the introduction of ionic tags and highly polar groups such as ammonium tags (Figure 1b) and PEGs (Figure

• ][53]. Grubbs and co-workers were the first to introduce water-soluble catalysts which displayed metathesis activity in aqueous media [54]. In 1996, Grubbs et al. reported that complexes 1 and 2 catalyze the living opening polymerization of norbornene derivatives 35 and 36 in neat water. Interestingly

• polymer is currently being investigated for possible biomedical applications. Table 4 summarizes the activities of the different ammonium-tagged catalysts discussed above with several water-soluble substrates. Catalysts 3 and 4 showed modest to excellent activities in the RCM of N,N-diallylated substrate

Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• Hibarigaoka, Tempaku-Cho, Toyohashi 441-8580, Japan 10.3762/bjoc.15.31 Abstract A reusable and highly enantioselective catalyst for the intramolecular cyclopropanation of various diazo ester and Weinreb amide derivatives was developed. The reactions catalyzed by a water-soluble Ru(II)-Amm-Pheox catalyst

• crucial for the intramolecular cyclopropanation reaction in a water/ether biphasic medium. The water-soluble catalyst could be reused at least six times with little loss in yield and enantioselectivity. Keywords: asymmetric synthesis; carbene transfer; cyclopropanation; diazoester; intramolecular

• diazoamide; Ru(II)-Pheox; water-soluble catalyst; Weinreb amide; Introduction Water-soluble transition metal complexes have been attracting increasing interest for catalytic applications because of their many advantages such as simple product separation, low cost, safety, and environmentally friendly