Alkoxide-Assisted Stereoselective Functionalization of 1,2-Bis-boronic Esters Under Photoredox Catalysis.

Site-specific functionalization of the secondary C-B bond of 1,2-bis-boronic esters has been proven to be an important method for the generation of 1,2-bis-functionalized compounds in a highly stereoselective manner. We have explored previously unknown secondary selective alkenylation, allylation, alkynylation and addition to aryl vinyl trifluoromethane, which proceeds via a novel reaction mechanism: alkoxide-mediated photoredox activation to generate secondary radicals over the primary one.

Predictive Nomogram and Propensity Score Matching in Neuroendocrine Carcinoma of the Tubular Gastrointestinal Tract: A US Population-Based Clinical Outcome Study.

Background: Neuroendocrine carcinomas (NECs) of the tubular gastrointestinal tract (GI-NECs) are rare and associated with worse clinical outcomes. This population-based study aims to highlight key demographics, clinicopathological factors, and survival outcomes in the US population. Methods: Data from 10,387 patients with GI-NECs were extracted from the Surveillance, Epidemiology, and End Result (SEER) database from 2000 to 2020. Results: Most patients were >40 years old at the time of presentation with a median age of 63 years old, with almost equal ethnic distribution per US population data. The most common primary tumor site was the small intestine (33.6%). The metastatic spread was localized in 34.8%, regional in 27.8%, and distant in 37.3% of cases, and the liver was the most common site of metastasis (19.9%) in known cases of metastases. Most NEC patients underwent surgery, presenting the highest 5-year overall survival of 73.2% with a 95% confidence interval (CI) (95% CI 72.0-74.4%), while chemotherapy alone had the lowest 5-year survival of 8.0% (95% CI 6.4-10.0%). Compared to men, women had a superior 5-year survival rate of 59.0% (95% CI 57.6-60.5%). On multivariate analysis, age > 65 (HR 2.49, 95% CI 2.36-2.54%, p ≤ 0.001), distant metastasis (HR 2.57, 95% CI 2.52-2.62%, p ≤ 0.001), tumor size > 4 mm (HR 1.98, 95%, CI 1.70-2.31%, p ≤ 0.001), esophageal (HR 1.49, 95% CI 0.86-2.58%, p ≤ 0.001), transverse colon (HR 1.95, 95% CI 1.15-3.33%, p ≤ 0.01), descending colon (HR 2.12, 95% CI 1.12, 3.97%, p = 0.02) anorectal sites, and liver or lung metastases were associated with worse survival. Surgical intervention and tumors located in the small intestine or appendix showed a better prognosis. Conclusion: GI-NECs are a group of rare malignancies associated with a poor prognosis. Therefore, epidemiological studies analyzing national databases may be the best alternative to have a more comprehensive understanding of this condition, assess the impact of current practices, and generate prognosis tools.

One pot conversion of phenols and anilines to aldehydes and ketones exploiting α gem boryl carbanions.

Functional group interconversion is an important asset in organic synthesis. Phenols/anilines being naturally abundant and the carbonyl being the most common in a wide range of bioactive molecules, an efficient conversion is of prime interest. The reported methods require transition metal catalyzed cross coupling which limits its applicability. Here we have described a method for synthesizing various aldehydes and ketones, starting from phenol and protected anilines via Csp2-O/N bond cleavage in a one-pot/stepwise manner. Our synthetic method is found to be compatible with a diverse range of phenols and anilines carrying sensitive functional groups including halides, esters, ketal, hydroxyl, alkenes, and terminal alkynes as well as the substitution on the aryl cores. A short-step synthesis of bioactive molecules and their functionalization have been executed. Starting from BINOL, a photocatalyst has been designed. Here, we have developed a transition metal-free protocol for the conversion of phenols and anilines to aldehydes and ketones.

Carbonyl group directed synthesis of 3-boryl-3-substituted alkenyl oxindoles and tetrasubstituted ß-borylenones.

Transition metal-free carbonyl directed boron-Wittig reaction of α-bis(boryl)carbanions with the corresponding isatins or with the α-keto esters/amides was achieved to access alkenyl oxindoles in good yield and high stereoselectivity.

Lupus Pancreatitis Masquerading as Pancreatic Cancer: A Rare Clinical Presentation.

Systemic lupus erythematosus (SLE) is an autoimmune multisystemic inflammatory disease. SLE-associated pancreatitis is uncommon, and pancreatic cancer in SLE is very rare. Imaging findings in SLE with pancreatitis can mimic malignancy. Endoscopic ultrasound with fine-needle aspiration/biopsy can guide in the accurate diagnosis and management of SLE-associated pancreatitis.

Pemphigus vulgaris presenting with epigastric pain.

Pemphigus vulgaris is an autoimmune mucocutaneous disease with an involvement in gastrointestinal tract especially in oral cavity and esophagus. Ulcers can be the initial presentation even before visible mucosal or cutaneous lesions. The presenting symptoms will be in accordance with the affected organ such as throat pain, hoarseness, dysphagia, odynophagia, or even bleeding. Here, we report a case of undiagnosed pemphigus vulgaris presenting with epigastric pain whose endoscopy showed oropharyngeal involvement and isolate esophageal ulcer, which failed proton pump inhibitor treatment.

Dissociable contributions of basolateral amygdala and ventrolateral orbitofrontal cortex to flexible learning under uncertainty.

Reversal learning measures the ability to form flexible associations between choice outcomes with stimuli and actions that precede them. This type of learning is thought to rely on several cortical and subcortical areas, including highly interconnected orbitofrontal cortex (OFC) and basolateral amygdala (BLA), and is often impaired in various neuropsychiatric and substance use disorders. However, unique contributions of these regions to stimulus- and action-based reversal learning have not been systematically compared using a chemogenetic approach and particularly before and after the first reversal that introduces new uncertainty. Here, we examined the roles of ventrolateral OFC (vlOFC) and BLA during reversal learning. Male and female rats were prepared with inhibitory DREADDs targeting projection neurons in these regions and tested on a series of deterministic and probabilistic reversals during which they learned about stimulus identity or side (left or right) associated with different reward probabilities. Using a counterbalanced within-subject design, we inhibited these regions prior to reversal sessions. We assessed initial and pre-post reversal changes in performance to measure learning and adjustments to reversals, respectively. We found that inhibition of vlOFC, but not BLA, eliminated adjustments to stimulus-based reversals. Inhibition of BLA, but not vlOFC, selectively impaired action-based probabilistic reversal learning, leaving deterministic reversal learning intact. vlOFC exhibited a sex-dependent role in early adjustment to action-based reversals, but not in overall learning. These results reveal dissociable roles for BLA and vlOFC in flexible learning and highlight a more crucial role for BLA in learning meaningful changes in the reward environment.

1,2-Metallate Rearrangement Using Indole Boronate Species to Access 2,3-Diarylindoles and Indolines.

A transition metal-free multicomponent reaction using lithiated indole, boronic ester, pyridine, and ethyl chloroformate was developed to access C2,C3 bis-arylated indoles, which are present in several marketed drugs and bioactive compounds. One-pot access to unsymmetrical C2,C3-diaryl indole from the parent indole remains a huge synthetic challenge. Our group was able to achieve this goal through a transition metal-free 1,2-metalate rearrangement of the indole boronate complex. The reaction of indole boronate species with activated pyridine allows 1,2-migration to access pyridyl-indoleboronate species, which will convert to the corresponding indole upon oxidation and indoline after deborylation. The reaction tolerates substituted pyridines, quinolone, isoquinoline, and more. Both aryl and alkyl boronic esters were accommodated under optimized reaction conditions. Apart from mechanistic studies using 11B-NMR, this methodology has been applied to the gram-scale synthesis of several bioactive compounds.

SpyGlass DS system-assisted retrieval of proximally migrated pancreatic duct stent in a patient with chronic pancreatitis.

Pancreatic duct (PD) stent migration is among the recognized complications of endoscopic retrograde cholangiopancreatography (ERCP) with PD stent placement. Proximal stent migration poses a challenge for removal due to risks of PD damage, smaller caliber, and possible stricture. Here, we present a case of SpyGlass DS system-assisted PD stent repositioning after failure with traditional tools.

Recent advances in the synthesis and reactivity of MIDA boronates.

Organoboron compounds have a wide-range of applications in synthetic methodologies, natural products, and bioactive molecule synthesis. The sensitivity of boronic acid toward most synthetic reagents makes it necessary to introduce a protecting group before its utilization. Benchtop stable MIDA boronates have been found compatible with various common synthetic reagents which opens the doors for the synthesis of various small building blocks, natural products, and bioactive compounds. MIDA boronate compounds have been extensively utilized in Suzuki Miyaura coupling and Iterative cross-coupling reactions for the total synthesis of bioactive molecules and polymerization reactions. Different MIDA boronate compounds like vinyl, acyl, formyl, acrylic, and α-carbonyl MIDA boronates also act as novel synthetic building blocks for various synthetic transformations in organic synthesis. This paper summarizes the importance of MIDA boronate compounds in various aspects of organic chemistry.

Iron Catalysis: A New Horizon Towards Organoboron-mediated C-C Cross-coupling.

Transition metal-catalyzed cross-couplings have had a profound impact on chemical synthesis. Among the various transition metals, iron has drawn huge attention due to its cost effectiveness, range of stable oxidation states, Lewis acidic property and releatively less toxicity. Iron complexes have exhibited an efficient catalytic activity towards the cross-coupling reaction using organomagnesium, organolithium and organozinc reagent. Organoboron compounds are also engaged as a coupling partner for Fe catalysed C-C bond forming reactions. Over the last two decades' various iron catalysed C-C bond forming reactions have been developed. This review will summarize the chronological development in this research area along with challenges appearing especially in the past decade.

Mechanistic dichotomy in the solvent dependent access to E vs. Z-allylic amines via decarboxylative vinylation of amino acids.

The solvent plays an important role in the photophysical properties of donor-acceptor based photocatalysts. The solvent-dependent access to E vs. Z-allylic amines was achieved via decarboxylative vinylation of amino acids with vinyl sulfones. Detailed experimental studies have been conducted to understand the role of the solvent in the reactivity and stereoselectivity of the vinylation reactions.

Aberrant Right Subclavian Artery Causing Dysphagia: A Case Report of Dysphagia Lusoria.

Dysphagia lusoria is a rare condition, with a prevalence of less than 1%, that occurs through secondary compression of the esophagus posteriorly by an aberrant right subclavian artery. It commonly presents with dysphagia to solids. Management is usually done with dietary modification; however, more severe and intractable cases may require surgical intervention. We describe this rare vascular anomaly in a 54-year-old female presenting with mechanical dysphagia.

Transition-Metal-Free Heterocyclic Carbon-Boron Bond Formation.

Heteroaryl boronic acids and esters are extremely important and valuable intermediates because of their wide application in the synthesis of marketed drugs and bioactive compounds. Over the last couple of decades, the construction of highly important heteroaryl carbon-boron bonds has created huge attention. The transition-metal-free protocols are more green, less sensitive to air and moisture, and also economically advantageous over the transition-metal-based protocols. The transition-metal-free C-H borylation of heteroarenes and C-X (X=halogen) borylation of heteroaryl halides represents an excellent approach for their synthesis. Also, various cyclization and alkyne activation protocols have been recently established for their synthesis. The goal of this review article is to summarize the existing literature and the current state of the art for transition-metal-free synthesis of heteroaryl boronic acid and esters.

Endoscopic diverticulotomy for Killian-Jamieson diverticulum: mid-term outcome and description of an ultra-short tunnel technique.

Background and study aims Killian-Jamieson Diverticulum (KJD) is a rarer and more recently described upper pharyngeal diverticulum than Zenker's diverticulum (ZD). KJD is more difficult to manage than ZD because it tends to extend lower into the upper mediastinum and the diverticulum neck is in close proximity to the recurrent laryngeal nerve. There is limited literature on KJD management and transcervical surgical diverticulectomy is the mainstay of therapy. Patients and methods Here we describe two methods of endoscopic diverticulotomy to treat KJD - direct and tunneling diverticulotomy (with hypopharyngeal tunnel or ultra-short tunnel - the latter being our preferred technique). Results This was a retrospective study including 13 consecutive patients between March 2015 and April 2018. Three patients received direct and 10 received tunneling diverticulotomy (7 with the hypopharyngeal tunnel and 3 with the ultra-short tunnel). All procedures were completed in 16 to 52 minutes. There was no incidence of bleeding, mediastinitis, or sign of recurrent laryngeal nerve injury. At follow up of 9 to 79 months (median 33), the clinical success rate was 92 % (12/13); 11 patients had complete symptom resolution (post-operative symptom score = 0) and one patient had near-complete symptom resolution (occasional residual dysphagia). One patient receiving direct myotomy had limited symptom relief (frequent residual dysphagia and occasional residual regurgitation), possibly related to incomplete myotomy. Conclusions Endoscopic tunneling diverticulotomy is a feasible, safe, and effective method to treat KJD.

Development of Methods to the Synthesis of ß-Boryl Acyls, Imines and Nitriles.

Organoboron compounds are highly important and versatile synthetic intermediates for the preparation of a wide range of organic molecules. Organoboron compounds have drawn significant attention among organic chemists due to their Lewis acidic property, non-toxicity, and commercial availability. Over the last several decades, there has been a substantial development of new organoboron compounds, useful in organic synthesis. Among all other organoboron compounds, ß-boryl carbonyl compounds are the important ones. The ß-boryl compounds have appeared as promising intermediates for various synthetic transformations. The 1,4-conjugate addition of diboron reagents to carbon-carbon double bond in the presence of different transition-metal catalysts has been extensively reported by various research groups across the globe. This mini-review outlines the numerous racemic as well as asymmetric ß-borylation methods developed to date.

Unique features of stimulus-based probabilistic reversal learning.

Reversal learning paradigms are widely used assays of behavioral flexibility with their probabilistic versions being more amenable to studying integration of reward outcomes over time. Prior research suggests differences between initial and reversal learning, including higher learning rates, a greater need for inhibitory control, and more perseveration after reversals. However, it is not well-understood what aspects of stimulus-based reversal learning are unique to reversals, and whether and how observed differences depend on reward probability. Here, we used a visual probabilistic discrimination and reversal learning paradigm where male and female rats selected between a pair of stimuli associated with different reward probabilities. We compared accuracy, rewards collected, omissions, latencies, win-stay/lose-shift strategies, and indices of perseveration across two different reward probability schedules. We found that discrimination and reversal learning are behaviorally more unique than similar: Fit of choice behavior using reinforcement learning models revealed a lower sensitivity to the difference in subjective reward values (greater exploration) and higher learning rates for the reversal phase. We also found latencies to choose the better option were greater in females than males, but only for the reversal phase. Further, animals employed more win-stay strategies during early discrimination and increased perseveration during early reversal learning. Interestingly, a consistent reward probability group difference emerged with a richer environment associated with longer reward collection latencies than a leaner environment. Future studies should systematically compare the neural correlates of fine-grained behavioral measures to reveal possible dissociations in how the circuitry is recruited in each phase. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Synthesis and reactivity of alkynyl boron compounds.

Over the last century, there have been considerable developments in organoboron chemistry due to the stability, non-toxicity, and easy commercial availability of various boronic esters. Several organoboron reagents have emerged and play an increasingly important role in everyday organic synthesis. Among them, alkynyl boron compounds have attracted significant attention due to their easy synthesis and diverse reactivity. In this review, we summarize the advancement of research on alkynyl boron compounds, highlighting their importance in the synthesis of valuable compounds.

Reversal of polarity by catalytic SET oxidation: synthesis of azabicyclo[m.n.0]alkanes via chemoselective reduction of amidines.

A one-pot catalytic method has been developed for the stereoselective synthesis of cyclopropane-fused cyclic amidines using CuBr2/K2S2O8 as an efficient single electron transfer (SET) oxidative system. The generality of this mild method is demonstrated with a wide variety of substrates to furnish pharmaceutically important amidines containing aza-bicyclic and novel aza-tricyclic frameworks in very good yields. A chemoselective reduction of cyclic amidines to 2-/3-azabicyclo[m.n.0]alkanes and octahydroindoles has been developed using a NaBH4/I2 reagent system. The synthetic scope of the chemoselective reduction of the amidine functionality has been exemplified in the stereoselective synthesis of an iminosugar based (±)-epiquinamide analogue.