Effect of Preoperative Body Mass Index on Postoperative and Long-Term Outcomes in an East Indian Gastric Cancer Cohort.

BACKGROUND: Gastric cancer is a global health concern with varying clinical outcomes. This study aims to investigate the influence of preoperative Body Mass Index (BMI) on survival in patients who underwent curative resection for gastric cancer in Eastern India. METHODS: Data from a prospectively maintained Surgical Oncology database were analysed for patients who underwent curative resection for primary gastric adenocarcinoma between May 2016 and March 2022. Patients with incomplete data were excluded. Preoperative BMI was categorised into three groups: Underweight (< 18.5 kg/m2), Normal (18.5-22.9 kg/m2), and Overweight/Obese (=23 kg/m2). Clinicopathological details, short-term outcomes, and long-term oncological outcomes were assessed. Statistical analysis included survival estimates, Cox proportional hazard models, and subgroup analysis. RESULT: Of 162 patients, 145 met the inclusion criteria. Patients were predominantly male (68%) with middle or lower socioeconomic status. No significant differences amongst BMI groups were observed in performance score, tumour grade, clinical stage, or short-term outcomes. Postoperative complications and 30-day mortality were similar. However, underweight patients had poorer 4-year disease-free survival (DFS) compared to overweight/obese patients (14.3% vs. 39.7%, p = 0.03). Overweight/obese patients showed significantly better 4-year overall survival (OS) than underweight patients (47.8% vs. 20.4%, p = 0.03). CONCLUSIONS: In Eastern Indian gastric cancer patients undergoing curative resection, preoperative higher BMI (overweight/obese) was associated with better long-term survival. Understanding these findings could guide tailored interventions to improve outcomes in this population.

Specific and Strong Acceleration of Nitrosation by Nitrosyl Sulfonates Using the Bis-Coordinating Lewis Acid TiCl4 or SnCl4.

Nitrosyl triflate is an excellent donor of NO+ to C═C and very unreactive benzenoids, in contrast to the much less reactive nitrosyl mesylate. However, both of these reagents are strongly activated by the bis-coordinating Lewis acids TiCl4 and SnCl4 and become super reactive NO+ donors. Strong catalysis and activation are even observed with the inherently less electrophilic nitrosyl trifluoroacetate. Monocoordinating strong Lewis acids, e.g., MeAlCl2, are relatively ineffective.

Synthetically Useful Transformations of Olefins via Cationic 1,2-Oxazetium Intermediates.

Nitrosyl triflate serves as a NO+ donor in reactions with many olefinic substrates to form reactive, cationic 1,2-oxazetium cycloadducts that can be converted selectively into a wide range of useful products depending on reagents and conditions.

Margin to Depth of Invasion Ratio: A Significant Predictor of Survival in Patients With Oral Cancer.

PURPOSE: A common definition of a clear margin (≥5 mm) in oral squamous cell carcinoma (OSCC) for all stages is a subject of controversy. Studies have shown that even 1- and 2-mm margins are adequate, and few studies have identified dynamic resection margin as a criterion. We aimed to study the margin to depth of invasion ratio (MDR), margin to tumor thickness ratio (MTR), and margin to tumor size ratio (MSR) as prognostic markers for survival. Notably, to our knowledge, this is the first study to evaluate the role of MDR in OSCC. METHODS: A prospectively maintained head and neck cancer database was analyzed from January 2017 to February 2023. The MDR, MTR, and MSR were calculated for each patient. Survival outcomes were analyzed using the Cox proportional model and the Kaplan-Meier method. Akaike's information criterion (AIC) and Bayesian information criterion (BIC) were used to compare different ratio models. X-tiles software was used to identify the optimal cutoff value of MDR. RESULTS: Two hundred eighty patients in the database were assessed, of which 123 eligible patients were enrolled in the study. MDR was an independent predictor of disease-free survival (DFS) on multivariate analysis. The MDR model had the lowest values on AIC and BIC analyses. A cutoff value of 0.5 for MDR showed a significant correlation with DFS and overall survival. CONCLUSION: MDR was the best predictor of recurrence of all the three ratios studied. The minimum safe surgical margin can be calculated by multiplying the depth of invasion by 0.5. This study signifies the role of dynamic resection margin criteria on the basis of MDR in defining clear margins.

Synthesis of Tetracyclic C2-Symmetric Ketiminium Salts and Evaluation as Catalysts for Epoxidation.

Short synthetic routes to the nonplanar tetracyclic ketiminium salt A and two close analogs are described. These are helical nonplanar structures as shown by X-ray crystallography.

Two Unprecedented Reactions of Nitrosyl Triflate: NO+-Induced Cationic Cascade Cyclization and C═C Oxidative Cleavage.

Nitrosyl triflate is shown to react with olefins in a CH2Cl2 solution by three different pathways depending on structure and reaction conditions: (1) cationic cyclization, (2) C═C cleavage, and (3) allylic nitrosation. Possible reaction pathways are described.

Mechanism of the Reaction of Olefins with Nitrous Anhydride (O═N-O-N═O) to Form 1,2-Oxazetes.

The mechanistic pathway for the formation of 1,2-oxazetes by reaction of olefins with nitrous anhydride has been clarified. The initial reaction intermediate, a ß-nitroso nitrite ester that is sensitive to light, undergoes O-NO fission to form a ß-nitroso alkoxy radical, even with ambient fluorescent lighting but much faster with blue light irradiation. The oxygen of the alkoxy radical subsequently adds to the adjacent nitroso group to generate a cyclic four-membered nitrosyl radical. The 1,2-oxazete is then produced by elimination to generate the C═N bond. No 1,2-oxazete formation occurs in the dark.

Nitrosyl Triflate and Nitrous Anhydride, Same Mode of Generation, but Very Different Reaction Pathways. Direct Synthesis of 1,2-Oxazetes, Nitroso or Bisoxazo Compounds from Olefins.

Nitrosyl triflate (TfONO) can be generated in situ from tetra-n-butylammonium nitrite and triflic anhydride (1:1) in CH2Cl2 solution at ca. -30 °C. It acts as a powerful and soluble nitrosating agent with a wide range of olefinic or aromatic substrates. Nitrous anhydride (O═N-O-N═O) can be generated in the same way using tetra-n-butylammonium nitrite and triflic anhydride (2:1) in CH2Cl2 solution at ca. -30 °C. Each reagent has been isolated and characterized. They react with olefins to give different products. Nitrosyl triflate is an excellent reagent for generating either vinylic or allylic nitroso compounds or their dimeric bisoxazo derivates. Nitrous anhydride efficiently converts many olefins to 1,2-oxazetes in a single step, making this class of compounds readily available from olefins for the first time. We have also discovered another route to 1,2-oxazetes involving a novel rearrangement/isomerization of allylic nitroso compounds which is catalyzed by Pd-C/H2.

Contrasting Diastereoselectivity between Cyclic Nitrones and Azomethine Ylides. Stereocontrolled Pathways to cis-anti-anti-cis-Oxazatetraquinanes from a Bicyclic Nitrone.

A study of [3 + 2] cycloaddition reactions of a bicyclic nitrone with various cyclopentenes has clarified the diastereomeric preferences as a function of the olefinic structure. It has also identified an important stereochemical difference between nitrones and the analogous azomethine ylides in [3 + 2] cycloaddition reactions.

A Useful Method for the Conversion of Olefins to Nitro Olefins.

Triflyl nitrate is easily generated from tetra-n-butylammonium nitrate in CH2Cl2 solution and serves as an effective nitrating agent for a wide range of unsaturated substrates to form nitro olefins.

Unraveling the C2-Symmetric Azatetraquinane System. Simple, Enantioselective Syntheses.

Concise stereocontrolled synthetic routes to the C2-symmetric azatetraquinane 1 (or, also, the enantiomer) are described. The successful execution of the synthesis involved innovation in the methodology for [3+2] cycloaddition and stereochemical control.

CuBr2-catalyzed diastereoselective allylation: total synthesis of decytospolides A and B and their C6-epimers.

An efficient CuBr2-catalyzed diastereoselective allylation of a cyclic hemiacetal with allyltrimethylsilane as a nucleophile has been developed. The protocol offers a cost effective, protecting group tolerant, and operationally simple approach to 2,6-trans-disubstituted tetrahydropyran with excellent diastereoselectivity. Furthermore, the application of this methodology has been demonstrated in the total synthesis of decytospolides A and B and their C6-epimers.

Total synthesis and stereochemical revision of relgro and 10'-oxorelgro.

The first asymmetric total synthesis and stereochemical assignments of 10-membered macrolactones relgro and 10'-oxorelgro are disclosed. To this end, palladium-catalyzed Stille coupling, the Mitsunobu reaction, ring-closing metathesis, EDCI promoted coupling and the Jacobsen hydrolytic kinetic resolution are used as key steps. The total synthesis followed by thorough evaluation of the optical rotation and CD spectral data led to the revision of the absolute configuration at C-6' for both relgro and 10'-oxorelgro. Moreover, the 1H as well as 13C NMR data are reported for the first time for relgro.

Total Synthesis of Four Isomers of the Proposed Structures of Cryptorigidifoliol K.

The first asymmetric convergent total synthesis of four isomers of proposed structures of cryptorigidifoliol K (1a, 1b, 1c, and 1d) has been achieved from commercially available starting materials. The key steps in this synthesis involve tandem isomerization followed by a C-O and C-C bond-forming reaction for the construction of trans-2,6-disubstituted dihydropyran, iodolactonization, isomerization of terminal alkene, and cross-metathesis reaction. The large discrepancies in the spectroscopic data (1H NMR) of synthetic cryptorigidifoliol K from the natural product suggest that the structure of the natural cryptorigidifoliol K requires revision.

Gold(I)-Catalyzed Cyclization for the Synthesis of 8-Hydroxy-3- substituted Isocoumarins: Total Synthesis of Exserolide F.

A highly regioselective gold(I)-catalyzed 6-endo-dig cyclization of 2,2-dimethyl-5-(alkynyl)-4H-benzo[d][1,3]dioxin-4-ones for the synthesis of 8-hydroxy-3-substituted isocoumarins is described. Key features of the reaction include the broad substrate scope, scalability, and tolerance for protecting groups. The synthetic utility of this novel method is demonstrated by the first total synthesis of exserolide F, an isocoumarin-containing polyol natural product.

First asymmetric total synthesis of aspergillide D.

The first asymmetric total synthesis of a 16-membered macrolide, aspergillide D, is described. The chiral centers of the acid are derived from d-ribose and the alcohol subunit from 1,8-octane diol through Sharpless kinetic resolution, respectively. The other key reactions include Yamaguchi esterification, ring-closing metathesis reaction, and Shiina macrolactonization to construct the fully functionalized macrocycle.

Total Synthesis of Tetraketide and Cryptorigidifoliol I via a Sequential Allylation Strategy.

A unified and efficient synthetic route for both tetraketide (1) and cryptorigidifoliol I (2) has been devised successfully from commercially available starting materials in 11 and 17 steps, with 16% and 11% overall yields, respectively. Highlights of the syntheses involved sequential Lewis acid-catalyzed highly regio- and diastereoselective allylations and intramolecular Mitsunobu lactonization.