Oxygen-Fueled Iterative Hydride Transfer Driven by a Rigid Planar Architecture.

An iterative hydride reduction/oxidation process was promoted under ambient conditions by a quasi-planar iminium cation rigidified by two concatenated quinoline units. The iminium proton was fixed by hydrogen bonding from neighboring quinoline nitrogen atoms, rendering the imine highly susceptible to hydride reduction with weak reductants, e.g., 1,4-dihydropyridines. The thus-formed amine was readily oxidized by molecular oxygen to regenerate the quasi-planar iminium cation under ambient conditions. This process was exploited for catalytic oxidation of 1,4-dihydropyridines as well as 9,10-dihydroacridine to highlight an intriguing rigidity-driven catalysis.

Convergent total synthesis of corallocin A.

The first total synthesis of corallocin A is described herein. The Suzuki coupling reaction as a key step proceeded with high stereoselectivity and in good yield. Robust transformations, including Vilsmeier-Haack formylation and Wittig reaction, allowed for effective access to corallocin A.

Direct Catalytic Asymmetric Addition of Alkylnitriles to Aldehydes with Designed Nickel-Carbene Complexes.

A direct catalytic asymmetric addition of acetonitrile to aldehydes that realizes over 90 % ee is the ultimate challenge in alkylnitrile addition chemistry. Herein, we report achieving high enantioselectivity by the strategic use of a sterically demanding NiII pincer carbene complex, which afforded highly enantioenriched ß-hydroxynitriles. This highly atom-economical process paves the way for exploiting inexpensive acetonitrile as a promising C2 building block in a practical synthetic toolbox for asymmetric catalysis.

Total Synthesis of Cochlearol†B via Intramolecular [2+2] Photocycloaddition.

Herein, we describe the first total synthesis of cochlearol B, a meroterpenoid natural product featuring a 4/5/6/6/6-fused pentacyclic structure. Key steps, oxidative cyclization and subsequent intramolecular [2+2] photocycloaddition, which constructed the pentacyclic structure in highly stereoselective manner, allowed efficient access to cochlearol B with the longest linear sequence of 16 steps, and in 9 % overall yield. Single-crystal X-ray crystallographic analysis clearly confirmed the stereochemistry of cochlearol B.

Anteroposterior molecular registries in ectoderm of the echinus rudiment.

BACKGROUND: Echinoderms and hemichordates are sister taxa that both have larvae with tripartite coeloms. Hemichordates inherit the coelom plan and ectoderm from larvae, whereas echinoderms form the adult rudiment comprising rearranged coeloms and a vestibule that then develops into adult oral ectoderm. Molecular networks that control patterns of the ectoderm and the central nervous system along the anteroposterior (AP) axis are highly conserved between hemichordates and chordates, respectively. In echinoderms, however, little is known about the AP registry in the ectoderm. RESULTS: We isolated ectodermal AP map genes from the sand dollar Peronella japonica and examined their expression. Comparative expression analyses showed that (1) P. japonica orthologs of hemichordate anterior markers are expressed in the larval apical plate, which degenerates during metamorphosis; (2) P. japonica orthologs of the medial markers are expressed in the ambulacral ectoderm of the rudiment; and (3) few P. japonica orthologs of the posterior markers are expressed in ectoderm. CONCLUSIONS: We suggest that echinoids only inherit the ambulacral ectoderm from a common ambulacrarian ancestor, which largely corresponds to the collar ectoderm in hemichordates. The ectodermal AP registry provides insights into the AP axis and evolutionary processes of echinoderms from a common ambulacrarian ancestor. Developmental Dynamics 247:1297-1307, 2018. © 2018 Wiley Periodicals, Inc.

Cyclols Revisited: Facile Synthesis of Medium-Sized Cyclic Peptides.

Medium-sized rings, particularly the corresponding cyclic peptides, are challenging synthetic targets. In the present study, we report an approach to medium-sized cyclic peptides through targeted formation and collapse of cyclol intermediates. This methodology operates on ß-amino imides derived from 2,5-diketopiperazines and offers a straightforward transition from frequently examined scaffolds in drug discovery to a rarely visited class of medium-sized rings.

Oxalyl Boronates Enable Modular Synthesis of Bioactive Imidazoles.

Described herein is the preparation of oxalyl boronate building blocks and their application for the construction of heterocycles. The oxalyl unit, readily accessible through commercially available starting materials, enables a modular approach for the synthesis of imidazoles. A variety of aromatic, heteroaromatic, and alkyl carboxaldehydes were condensed with oxalyl boronates to afford substituted boryl imidazoles in a regiocontrolled fashion. Subsequent palladium-catalyzed cross-coupling with haloarenes furnished the desired trisubstituted imidazole scaffolds. To demonstrate the utility of these scaffolds, potent inhibitors of the serine/threonine-protein kinase STK10 were synthesized.

Synthesis of Aminoboronic Acid Derivatives from Amines and Amphoteric Boryl Carbonyl Compounds.

Herein, we demonstrate the use of α-boryl aldehydes and acyl boronates in the synthesis of aminoboronic acid derivatives. This work highlights the untapped potential of boron-substituted iminium ions and offers insights into the behavior of N-methyliminodiacetyl (MIDA) boronates during condensation and tautomerization processes. The preparative value of this contribution lies in the demonstration that various amines, including linear and cyclic peptides, can be readily conjugated with boron-containing fragments. A mild deprotection of amino MIDA-boronates enables access to α- and ß-aminoboronic acids in high chemical yields. This simple process should be applicable to the synthesis of a wide range of bioactive molecules as well as precursors for cross-coupling reactions.

Indocyanine green lymphography and lymphaticovenous anastomosis for generalized lymphatic dysplasia with pleural effusion and ascites in neonates.

BACKGROUND: The fatality rate of generalized lymphatic dysplasia (GLD) with chylous pleural effusion and ascites is particularly high when it persists over a prolonged period. The purpose of this report was to determine the utility of indocyanine green (ICG) lymphography and lymphaticovenous anastomosis (LVA) in GLD with chylous pleural effusion and ascites in neonates. METHODS: We tested the lymphatic function in the 4 extremities for 8 GLD neonate patients using ICG lymphography, and on the basis of the results, we performed LVA for 5 of them. LVA was performed at the extremities under general anesthesia using incisions <1 cm in length. The outcome of LVA was evaluated with the amount of ascites discharged from thoracostomy tube or abdominal tube, except for 1 patient who had no drainage tube. RESULTS: In all cases, ICG lymphography showed varying degrees of dermal backflow in the limbs with lymphostasis. After LVA surgery, effusion stopped in 2 cases and decreased in 1 case. In the cases where effusion stopped, backflow as observed with ICG lymphography was minimal, and in the case where effusion decreased but did not stop, backflow was moderate. CONCLUSIONS: The application of ICG and LVA could possibly be used to diagnose and treat lymphatic pleural effusion or ascites.

Boron-containing enamine and enamide linchpins in the synthesis of nitrogen heterocycles.

The use of α-boryl enamine and enamide linchpins in the synthesis of nitrogen heterocycles has been demonstrated. Boryl enamines provide ready access to the corresponding α-halo aldehydes, which undergo regioselective annulation to form borylated thiazoles. A condensation/amidation sequence converts α-boryl aldehydes into stable α-boryl enamides without concomitant C → N migration. We also show that palladium-catalyzed cyclization of α-boryl enamides leads to synthetically versatile isoindolones. These molecules can be subsequently used to access polycyclic scaffolds.

Evaluation of lymphatic dysplasia in patients with congenital pleural effusion and ascites using indocyanine green lymphography.

OBJECTIVES: To investigate the use of indocyanine green (ICG) lymphography in the diagnosis and assessment of the severity of lymphatic dysfunction in infants and neonates with congenital lymphatic pleural effusion and ascites. STUDY DESIGN: We performed ICG lymphography on 10 neonates and infants with congenital lymphatic pleural effusion and ascites. After the subcutaneous injection of ICG, circumferential fluorescent images of lymphatic drainage channels in the extremities and trunk were identified using an infrared camera system. The lymphographic findings were classifiable into 2 patterns-those showing a linear lymphatic pattern, suggesting normal lymphatic flow, and those showing lymphatic channels with retrograde lymphatic flow (dermal backflow pattern), suggesting an abnormal lymphatic flow. We analyzed the severity of the ICG lymphography findings and the clinical outcomes. RESULTS: Based on the ICG lymphography, the severity of lymphatic dysplasia were classified into 4 categories: mild dysplasia, moderate dysplasia, severe dysplasia, and lymphatic hypoplasia. All cases diagnosed with mild (n = 3) or moderate dysplasia (n = 2) survived, and 2 of the 4 cases diagnosed with severe dysplasia died. The duration of endotracheal intubation ranged from 1 to 17 days (median, 7) in the patients with mild or moderate dysplasia and from 25 to 110 days (median, 77) in those with severe dysplasia. CONCLUSIONS: The ICG lymphographic findings were consistent with the clinical conditions. This imaging technique may be important to the future clinical management of lymphatic dysplasia in neonates and infants.

Stereocontrolled disruption of the Ugi reaction toward the production of chiral piperazinones: substrate scope and process development.

The factors determining diastereoselectivity observed in the multicomponent conversion of amino acids, aziridine aldehyde dimers, and isocyanides into chiral piperazinones have been investigated. Amino acid-dependent selectivity for either trans- or cis-substituted piperazinone products has been achieved. An experimentally determined diastereoselectivity model for the three-component reaction driven by aziridine aldehyde dimers has predictive value for different substrate classes. Moreover, this model is useful in reconciling the previously reported observations in multicomponent reactions between isocyanides, α-amino acids, and monofunctional aldehydes.

Precursor-directed biosynthesis and biological activity of tripropeptin Cpip, a new tripropeptin C analog containing pipecolic acid.

Tripropeptin C, a non-ribosomal cyclic lipopeptide containing three proline residues, exhibits excellent efficacy in the mouse-methicillin-resistant Staphylococcus aureus septicemia model. Since tripropeptins contain L-prolyl-D-proline and, as a result, are known to form a hairpin structure in proteins, it was of interest to determine whether this substructure contributes to their antibacterial activity. In this study, prolines in tripropeptin C were replaced with pipecolic acid(s) using precursor-directed biosynthesis. Only a new tripropeptin analog, tripropeptin Cpip, which has one L-pipecolic acid in place of L-proline, was isolated. The in vitro antimicrobial activity of the new analog was approximately two to four times weaker activity against Gram-positive bacteria, including drug-resistant species, compared with that of tripropeptin C. These results suggest that the L-prolyl-D-proline substructure plays an important role in the observed potency of tripropeptins.

Enantioselective Total Syntheses of (+)-Ganocin A and (-)-Cochlearol B.

Herein, we report the total syntheses of (+)-ganocin A and (-)-cochlearol B, featuring pentacyclic skeletons, in optically active forms. We utilized asymmetric Corey-Bakshi-Shibata reduction, phenolic oxidative cyclization, the intramolecular radical cyclization-benzylic oxidative cyclization sequence, and intramolecular [2 + 2] photocycloaddition. These key steps enabled enantioselective access with the longest linear sequence of 17 steps and 9% overall yield for (+)-ganocin A and with 16 steps and 9% overall yield for (-)-cohlearol B.

Oxidative geminal functionalization of organoboron compounds.

Excellent tolerance: Stable acylboronates equipped with N-methyliminodiacetyl (MIDA) boryl groups ([B]) were prepared by using a sequence of oxidative manipulations at the boron-bound carbon center (green in scheme). Chemoselective transformations of these acylated organoboron building blocks yielded a range of multifunctionalized boron derivatives and supplied access to valuable borylated heterocycles (see scheme).

Diastereoselective Direct Catalytic Asymmetric Mannich-Type Reactions of Alkylnitriles with a Ni(II)-Carbene Complex.

Despite recent advances in reactions using alkylnitriles as carbon nucleophiles, diastereoselective direct catalytic asymmetric reactions, in which two consecutive chiral centers could be controlled, remain largely unexplored. Herein, we report the addition of alkylnitriles (such as propionitrile) to imines in the presence of a catalytic amount of a chiral pincer-type Ni-carbene complex and potassium 2,6-di-tert-butyl-4-methylphenoxide (KBHT). BHT and molecular sieves were used as additives to improve the yields, diastereoselectivity, and enantiomeric ratio up to >99%, 90:10 anti/syn, and 97.5:2.5 er, respectively. The Mannich adducts can be readily converted to the corresponding ß-amino acids.

High regression rate of coronary aneurysms developed in patients with immune globulin-resistant Kawasaki disease treated with steroid pulse therapy.

Kawasaki disease is an acute vasculitis syndrome of unknown etiology that mainly affects small and medium-size arteries, particularly the coronary artery. Coronary artery lesions may develop into aneurismal formation and thrombotic occlusion, and progress to ischemic heart disease. The aim of the present study was to investigate the effect of steroid pulse therapy following intravenous immune globulin (IVIG) treatment on the regression rate of aneurysms in Kawasaki disease. Among 93 sequential patients referred to us, because of coronary artery lesions in the acute phase, we found 23 aneurysms in 12 patients during the period from January 1997 to January 2008. We divided them into two groups: a non-steroid group, 7 patients (13 aneurysms) treated with single or multiple IVIG but no steroid pulse therapy; and a steroid group, 5 patients (10 aneurysms) treated with multiple IVIG followed by steroid pulse therapy. We compared the regression rate of the aneurysms between the two groups, retrospectively. The regression rates of the aneurysms in the steroid group were significantly higher than those in the non-steroid group when we analyzed 1) all aneurysms (p = 0.007), 2) giant aneurysms (aneurismal diameter was 4 or more x normal, or > 8 mm) (p = 0.018), and 3) aneurysms in IVIG-resistant patients who were resistant to initial IVIG therapy (p = 0.035). All aneurysms, including the giant aneurysms in the steroid group, regressed, and the regression rate of the aneurysms in the non-steroid group was about 46%(6/13). Steroid pulse therapy may be beneficial for IVIG-resistant patients. Our data suggest that steroid pulse therapy may lead to regression of aneurysms.

Author Correction: TriQuinoline.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

TriQuinoline.

The bottom-up synthesis of structurally well-defined motifs of graphitic materials is crucial to understanding their physicochemical properties and to elicit new functions. Herein, we report the design and synthesis of TriQuinoline (TQ) as a molecular model for pyridinic-nitrogen defects in graphene sheets. TQ is a trimer of quinoline units concatenated at the 2- and 8-positions in a head-to-tail fashion, whose structure leads to unusual aromatisation behaviour at the final stage of the synthesis. The central atomic-sized void endows TQ with high proton affinity, which was confirmed empirically and computationally. TQ•H+ is a two-dimensional cationic molecule that displays both π-π and CH-π contact modes, culminating in the formation of the ternary complex ([12]cycloparaphenylene(CPP) ⊃ (TQ•H+/coronene)) that consists of TQ•H+, coronene (flat), and [12]cycloparaphenylene ([12]CPP) (ring). The water-miscibility of TQ•H+ allows it to serve as an efficient DNA intercalator for e.g. the inhibition of topoisomerase I activity.

The neutrophil-to-lymphocyte ratio (NLR) predicts short-term and long-term outcomes in gastric cancer patients.

BACKGROUND: The preoperative neutrophil-to-lymphocyte ratio (NLR) is a well-known prognostic marker for gastric cancer patients. However, the utility of the NLR in predicting short-term outcomes in gastric cancer patients remains unclear. Here, we investigated whether the preoperative NLR is a predictor of short-term outcomes in gastric cancer patients. METHODS: We retrospectively evaluated 154 consecutive gastric cancer patients. We compared the perioperative outcomes and median survival times (MSTs). In particular, for stage II/III (UICC, 7th edition) gastric cancer patients, we compared median disease-free survival time (MDFST) between the low- and high-NLR groups. RESULTS: Between the low-NLR group (n = 110) and the high-NLR group (n = 44), significant differences were observed in perioperative outcomes, including postoperative complications (3 (2.7%) vs. 5 (11.3%); p = 0.015), intraoperative blood loss (158 ± 168 g vs. 232 ± 433 g; p = 0.022), and intraoperative blood transfusions (0 vs. 3 (6.8%); p = 0.042). MSTs and MDFSTs were also significantly different (812 vs. 594 days, p = 0.04; and 848 vs. 475 days, p = 0.03, respectively). Multivariate analysis identified the NLR (hazard ratio [HR], 2.015; p = 0.004), Glasgow Prognostic Score (GPS) (HR, 1.533; p = 0.012), and presence of stage III/IV disease (HR, 5.488; p < 0.001), preoperative symptoms (HR, 3.412; p = 0.008), or postoperative complications (HR, 2.698; p < 0.001) as independent prognostic factors. CONCLUSIONS: We suggest that the preoperative NLR is an additional useful predictor of both long-term and short-term outcomes in gastric cancer patients.