The Cover Feature shows a novel strategy for the formal synthesis of camptothecin, which can be isolated from Camptotheca acuminate (also called happy tree) and used as an anti‐cancer agent in traditional Chinese medicine. The key step is a photo‐catalytic decarboxylative radical Michael addition for the efficient construction of the pentacyclic parent core by visible light. As is symbolically illustrated in the cartoon, the shining sunlight can directly transform the ABC rings to the main structure...
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An efficient and practical one‐pot strategy for the synthesis of N ‐sulfonylformamidines was developed by directly using easily available sulfonyl chlorides, sodium azide and tertiary/secondary amines in the presence of 5 mol% CuBr 2 under aerobic oxidative conditions.
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Direct access to non‐hydrolyzable glycoconjugates is highly mandatory for stabilizing their intrinsic biological or physical‐chemistry properties in the surrounding environment. Here, a simple and versatile approach for the preparation of multifunctional clickable β‐ C ‐glycoconjugates has been developed. Readily accessible N , N’ ‐disubstituted barbituric acids have been synthesized and ligated in water to the reducing end of unprotected carbohydrates via Knoevenagel condensation. Additionally,...
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The basicities of simple organic bases – aliphatic and aromatic amines, amidines, phosphazenes, as well as saturated and unsaturated nitrogen heterocycles – are examined in acetonitrile, dimethyl sulfoxide, tetrahydrofuran, water and the gas phase. The basicities (pKaH values) of conjugate acids of a large variety of bases in these media are presented and discussed. Equations employing easily usable structural descriptors have been derived for approximately converting basicities from acetonitrile...
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The construction of α‐(hetero)aryl ethenesulfonyl fluorides was achieved via a Pd‐catalyzed Suzuki coupling of arylboronic acids with 1‐bromoethene‐1‐sulfonyl fluoride (1‐Br‐ESF). The novel α‐aryl ethenesulfonyl fluorides were found to be another selectively addressable bis ‐electrophile for wide diversification through SuFEx click chemistry, or Michael addition with excellent chemical discrimination.
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The reaction of 1,2‐diaryl‐1,2‐diketones, propiolic acid esters, and C60 in the presence of Et3N gave cyclopentene‐annulated fullerenes via [3+2] cycloaddition. They were formed in two Et3N‐promoted[A1] steps, namely, the generation of 1,3‐bifunctional allenes and the cycloaddition of 1,3‐bifunctional allenes with C60. Interestingly, when a similar reaction was conducted using a flow packed‐bed reactor in combination with a silica‐supported tertiary amine, cyclobutane‐annulated fullerenes were obtained...
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3 H ‐benzo[ e ]isoindolin‐3‐ones were prepared via a two step process from naphthamides. The methodology involved efficient and selective mono and bis functionalisation of naphthtalene substrates. The sequence is based on alkoxylation or arylation reactions followed by a alkenylation‐annulation cascade. Our strategy provided the first dual Pd‐ and Rh‐promoted access to diversely substituted angular naphtalene‐based isoindolin‐3‐ones characterized by an unprecedented isomeric molecular arrangement....
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A focused family of naturally inspired chromenone dimers has been synthesized and studied for anticancer activity. Select dimeric chromenones prepared in this study have were found to have moderate cytotoxicity toward L5178Y and HL60 cells. These compounds may serve as promising leads for the identification of new ligands and biological targets. Select dimeric chromenones exhibit low micromolar cytotoxicity toward lymphoma and leukemia cell lines, L5178Y and HL60, respectively. The bioactive...
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CuO‐catalyzed 1,3‐addition of diaryliodonium triflates to diazo esters was realized under mild conditions. By this manner, a series of β‐aryloxyl acrylates compounds with triflate group were readily synthesized and could be further modified via cross‐coupling reactions. CuO‐catalyzed 1,3‐addition of diaryliodonium triflates to diazo esters was realized. This new strategy forms a series of triflate‐substituted β‐aryloxyl acrylate compounds with good tolerance of functional groups and excellent...
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An unprecedented direct alkynylation reaction of α‐C(sp3)–H bonds of ethers under visible light irradiation at room temperature without external photocatalyst was developed. A direct alkynylation of C(sp3)–H bonds adjacent to an oxygen atom of ethers under visible light irradiation was developed in the absence of an external photocatalyst. The reaction of ethers and alkynyl bromides underwent smoothly to generate the corresponding products in good yields with excellent functional‐group tolerance....
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A transition‐metal‐free, redox‐neutral, organocatalytic C3‐alkenylation of pyrroles is reported. Readily available aldehydes were employed as alkenylating agent and the reaction allows tolerance of several key functional groups in the products. The E ‐alkenylated products were isolated in moderate to exclusive selectivity. A one‐pot two‐fold alkenylation strategy is also developed for further downstream modifications. To show the applicability, synthetically challenging indolylpyrrole derivatives...
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In recent years, there has been an increasing tendency to use biocatalysts in industrial chemistry, especially in the pharma‐ and fine chemical sector. Preferably, enzymes or whole cells, applied as catalysts for a specific biotransformation, are utilized in aqueous reaction media since water is the natural medium for enzymes. In numerous examples of biocatalytic systems, however, a major problem is the insolubility of hydrophobic substrates in such aqueous reaction media. Apart from lipases, many...
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1‐Aryltriazenes, the protected and more stable form of aryl‐diazonium species, can be conveniently unmasked with Brønsted acidic‐IL or Sc(OTf)3 and coupled with a host of aryl/heteroaryl boronic acids, styrenes, and aryl/alkyl acetylenes in the Suzuki, Heck and Sonogashira reactions in one‐pot and in respectable isolated yields, by using palladium or nickel catalyst in readily available imidazolium ILs as solvent, under mild conditions. The scope of these reactions are explored, and the potential...
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The reaction mechanisms of nickel‐catalyzed heterodiarylation of alkenes are explored by DFT calculations. The competition of the diarylation against the potential side reactions, such as Heck coupling and Suzuki–Miyaura coupling, is analyzed in great detail. A density functional theory study on nickel‐catalyzed diarylation of styrene (R1) with arylboron (R2) and aryl bromide (R3) is presented in this article, to unveil the plausible mechanism and the competition of the potential side reactions....
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A catalyst‐free oxidative decyanation–amidation reaction is developed for the synthesis of α‐ketoamides using β‐ketonitriles, primary amines, and hydrogen peroxide sodium carbonate adduct (Na2CO3·1.5H2O2). This method is a valuable and simple strategy for the decyanation reaction. AN oxidative decyanation–amidation of β‐ketonitriles and primary amines readily occurs using hydrogen peroxide sodium carbonate adduct (Na2CO3·1.5H2O2), K2CO3, and 1,4‐dioxane. This reaction affords α‐ketoamides under...
23h
A photoinduced reaction between diazoketones, isocyanides and silanols, followed by aldol dimerization of the resulting multicomponent adduct, afforded polyfunctionalized 3,5‐dihydroxypyrrolidin‐2‐one heterocycles in a straightforward manner. With this methodology a high increment of complexity could be achieved, with six new bonds formed in just two steps. A photoinduced reaction between diazoketones, isocyanides and silanols, followed by aldol dimerization of the resulting multicomponent...
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The metal‐free C–S bond cleavage process has been established to construct N‐substituted acrylamide and β‐aminopropanamide derivatives in the presence of Selectfluor. Metal‐free and Selectfluor‐mediated C–S bond cleavage is described. This novel strategy provides a facile and efficient method to access important N‐substituted acrylamide and β‐aminopropanamide derivatives with good functional group tolerance and yields.
23h
No metal, no cry! Macrocyclic polyamines (MPAs) are important chelating agents for cations, anions, and neutral molecules; cyclen and DOTA are well‐known contrast agents for MR or PET/SPECT imaging. Their unique properties also make them attractive multivalent molecular platforms for applications far beyond conventional metal chelation. Their use in materials chemistry, medicinal chemistry, and chemical biology is discussed. Recent advances in the use of radiometals for both imaging and therapy...
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ConclusionLow-dose RT is a very effective treatment for the management of painful benign skeletal disorders. Due to the delayed onset of analgesic effects, low-dose RT results in significantly improved long-term efficacy compared to the results immediately after RT. These findings confirm the results of other retrospective, prospective, and randomized trials. (Source: Strahlentherapie und Onkologie)
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ConclusionsFor intermediate-risk as well as early stage high-risk BC patients, the DEGRO Breast Cancer Expert Panel recommends the use of PMRT following SSME and NSME when a 10-year locoregional recurrence risk is likely to be greater than 10%, as estimated by clinical and biological risk factors. Subvolume-only radiation is discouraged outside of trials. The impact of adequate systemic treatment and the value of radiotherapy on optimal locoregional tumor control, wit h the goal of less than 5%...
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At my practice, we previously showed that toric ICL implantation was effective in terms of safety, efficacy, predictability, and stability for the correction of refractive errors for mild and stable keratoconus,1,2 and that the disease did not progress, even in the late postoperative period.3 Accordingly, considering that this patient’s left eye had 7.25 D of astigmatism, this eye was not a good indication for toric ICL implantation alone. Moreover, even if postoperative rotation did not occur, some...
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In a recent issue, Frisina et al.1 decribed iris-claw intraocular lens (IOL) fixation using a needle-guided retropupillary method. We have been using the same surgical technique for the past 3 years,A the only difference being the absence of the 30-gauge needle to engage the long straight needle. It has become our preferred procedure for the correction of aphakia in eyes without capsule support because it is much easier to enclavate the iris-claw IOL to the posterior surface of the iris, when possible,...
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This 39-year-old patient has central keratoconus with more involvement in the left eye. Stability is relative in patients with keratoconus, and it is unclear whether her current complaints have been present since the initial ICL surgery 2 years prior or whether this represents progression of her corneal disease. Despite her current 20/30 UDVA, this patient is reporting blurry vision with diplopia. A rough estimate is that 1.0 D of ICL add power will correct about 0.7 D of refractive astigmatism at...
6h
Because the ICL was previously repositioned already three times, an additional repositioning was considered as not useful. An ultrasound biomicroscopy is planned to rule out any anatomical anomaly or (multiple) cysts in the iridociliary sulcus.
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A recent Consultation Section1 outlined several approaches for managing capsulorhexis phimosis, including neodymium:YAG (Nd:YAG) laser anterior capsulotomy, radiofrequency capsulotomy needle use, microscissors dissection, femtosecond laser use, and high-frequency diathermy cutting. Vitrector trimming of the fibrotic anterior capsule is another useful technique to surgically manage capsule contraction syndrome. First reported by Wilson et al.2 in 1994 and later described by Yeh et al. in 2002,3 vitrector...
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The authors agree on the importance of paying attention to every surgical step during needle-guided retropupillary fixation of iris-claw IOLs without underestimating even the simplest maneuvers. The iris is delicate and fluffy tissue and is not easy to manage. When traumatized by surgical maneuvers, the iris frays easily and releases pigment. Stretching it could result in an irregular pupil (corectopia). A long straight needle must be placed in the anterior chamber using a bimanual technique. A 30-gauge...
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This meta-analysis studied toric intraocular lens (IOL) alignment accuracy using image-guided and manual marking methods by comparing the axis misalignment of toric IOLs, percentage of eyes with toric IOL axis misalignment within ±5 degrees, postoperative astigmatism, difference vector, and postoperative uncorrected distance visual acuity. The methodological quality was assessed using the modified Quality Assessment of Diagnostic Accuracy Studies-2 tool. Continuous variables were analyzed using weighted...
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Traumatic cases in ophthalmology are of special concern. The extent of injury can vary from simple superficial epithelial defect to gross ocular avulsions, or from a simple concussion injury to a penetrating injury. In cases of blunt trauma, the manifestations are variable, and amongst the many complications, lenticular injuries require detailed evaluation. The usual lens injuries are opacification of lens matter, with or without any capsular discontinuity; however, in the presence of media opacity,...
6h
In his letter, Dr. Packard states that the recorded incision enlargements might not reflect the true incision size for each injector. It is true that every measurement system has uncertainty, and our study might have been limited by the resolution of the ruler and the stability of the human hand. To mitigate this issue, we used very thin purpose-made F-gauges with rounded edges to prevent incision enlargement. The F-gauges were designed to increase in increments of 0.1 mm (±0.01 mm) to allow precise...
6h
First, I recommend implanting Ferrara-type ICRS and then explanting the toric ICL (two-step procedure). The implant of a spherical or toric IOL in cases of keratoconus should be considered for those cases where the morphology of the cornea has been previously corrected and stabilized by Ferrara-type ICRS.1
6h
The introduction of mitomycin-C (MMC) has improved the outcomes of photorefractive keratectomy (PRK) by preventing haze formation and reducing light scatter.1 Mitomycin-C is routinely used when the ablation depth goes beyond certain limits (eg, ablations deeper than 60 mm) and in hyperopic and highly toric ablations.2 Some surgeons use MMC for every excimer laser ablation regardless of the intended correction.
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In their article, Arboleda et al.1 describe a study of rabbit eyes comparing 13 intraocular lens (IOL) injectors and their effect on clear corneal wounds. Various measurements of the size of the injectors were taken, and these were then related to the size of incision needed for the injectors to pass through. All initials incisions were 1.8 mm; they were then enlarged with the same knife used to make the initial incision. The authors state that incision enlargement was performed in 0.1 mm increments.
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The implantation of an ICL for myopia and myopic astigmatism in eyes with keratoconus has a great potential to end with an unpredictable outcome because of cone, irregular astigmatism, and instable refraction. Changing refraction and progression of the disease because of the biomechanically instable cornea causes fluctuation in vision. In the presented case, a hypervault of the implanted ICL also caused pigment dispersion and an imprecise refractive outcome. Because the patient reports blurry vision...
6h
A 39-year-old woman was seen because of dissatisfying results after an implantable collamer lens (ICL) (Visian ICL, STAAR Surgical Co.) implantation in the left eye. The ICL implantation was performed in 2017 because of stable keratoconus with contact lens intolerance. The preoperative corrected distance visual acuity (CDVA) was 20/25 in the right eye (−1.25 −3.0 × 40) and 20/25 in the left eye (−0.25 −7.25 × 145). A 13.7 mm ICL (−7.5 +6.0 × 54) was implanted in the left eye at the horizontal axis.
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To determine the distribution and quantity of ophthalmic viscosurgical device (OVD) retained in the lens capsular bag after irrigation/aspiration (I/A) in experimental cataract surgery.
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To provide an initial experience of novel phakic presbyopic intraocular lens in the correction of high myopia and presbyopia.
9h
We developed an optimized novel pupil expander device that addresses the shortcomings of existing devices, and compared it with several commercially available devices to show the benefits of our design.
9h
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