Dearomative annulation reaction of acyl-tethered benzothiazole bisnucleophiles with β'-acetoxy allenoates by switching the Lewis base is developed. The DBU-catalyzed reaction gives benzothiazole-fused 1,4-dihydropyridine carboxylates by (3 + 3) annulation chemoselectively. By contrast, the PR-catalyzed reaction gives benzothiazole-fused azepines by (4 + 3) annulation and cyclopentene carboxylates by (4 + 1) annulation; the ratio of the latter two products depends on the solvent.
View Article and Find Full Text PDFAim And Objective: The present case report aims to describe the nonsurgical management of an anterior tooth with a blunderbuss canal and an open apex using mineral trioxide aggregate (MTA) under magnification.
Background: When pulp is traumatized before root formation, it results in pulpal necrosis, due to which dentin and root formation are interrupted. As a result, the canal remains broad due to thin and fragile dentin walls leading to the open apex.
Introduction: Necrotizing soft tissue infections (NSTIs) are associated with a fulminating course because of their rapid destruction of tissue planes underlying the skin. -associated monomicrobial NSTIs are usually associated with exposure to fresh water, particularly among agricultural workers and fish handlers. Albeit uncommon in incidence, urgent medical and surgical intervention are required once a diagnosis has been made.
View Article and Find Full Text PDFA DMAP-catalyzed sequential benzannulation and lactonization strategy in which δ-acetoxy allenoate functions as a in its reaction with cyclic sulfamidate imines is reported. This platform delivers π-extended coumarin frameworks under metal-free conditions via allylic elimination followed by Mannich coupling, proton shifts, C-N bond cleavage, and lactonization as key steps. The driving force for this domino reaction is the formation of the diene-ammonium intermediate and O-S bond cleavage.
View Article and Find Full Text PDFLewis base dependent (3 + 3) annulation of δ-acetoxy allenoates with benzofuranone, pyrazolone, and Boc-protected oxindole is reported. In the presence of catalytic DBU, oxindole, benzofuranone, and pyrazolone undergo (3 + 3) annulation with δ-acetoxy allenoates 6- cyclisation at room temperature (25 °C) to afford fused pyran scaffolds. On the other hand, by employing catalytic DMAP, the reaction between -Boc-oxindole and δ-acetoxy allenoates goes through 6- cyclisation, leading to distinct dihydropyrans that contain an exocyclic double bond; similar products were also obtained by using benzofuranone and pyrazolone.
View Article and Find Full Text PDFThe reactivity of 2-sulfonamidoindoles with acetoxy allenoates under phosphine catalysis depends on the disposition of the acetoxy (OAc) group on the allenoate. In the temperature-controlled [3 + 3] annulations, δ-acetoxy allenoates afforded dihydrocarboline and carboline scaffolds with carbon-nitrogen nucleophilic 2-sulfonamidoindoles, in which allenoate serves as a β-, γ-, and δ-carbon donor. At room temperature (25 °C), dihydro-α-carboline motifs were obtained exclusively through Michael addition, 1,4-proton shift, isomerization, 1,2-proton transfer, phosphine elimination, and aza-Michael addition.
View Article and Find Full Text PDFSpiro-annulation involving δ-acetoxy allenoate and alkyl benzoisothiazole dioxide (-sulfonyl ketimine) triggered by DABCO/MeCOH combination leads to an via chemo- and regiospecific [4 + 2]-carboannulation and a new group is introduced. In contrast, DMAP-catalyzed benzannulation using the same reactants affords unsymmetrical -teraryls via Mannich coupling, sequential proton transfers, and C-N bond cleavage. Here, δ-acetoxy allenoate serves as a 4C-synthon and the carboannulation is completely base dependent and mutually exclusive.
View Article and Find Full Text PDFDuring the host immune response, the precise balance of the immune system, regulated by immune checkpoint, is required to avoid infection and cancer. These immune checkpoints are the mainstream regulator of the immune response and are crucial for self-tolerance. During the last decade, various new immune checkpoint molecules have been studied, providing an attractive path to evaluate their potential role as targets for effective therapeutic interventions.
View Article and Find Full Text PDFIn this review, we summarize advances in [4+3] and a few other annulation/cycloaddition reactions for the construction of seven membered rings, with an emphasis on the literature subsequent to the year 2010. The type of products include the following: azepines, diazepines, benzazepinones, 1,2-diazepinones, oxazepinones, benzothiazepines, benzodiazepinones, benzoxopinones, cyclohepta[b]indoles, benzoxazepines, azepino-indoles, oxepines/oxazepanes, triazepines oxepinoindolones/azepinoindolones, oxadiazepines, azabicyclooctanes. Emphasis is also given to cover diverse types of annulations; possible intermediates are displayed in the illustrated schemes to aid future work.
View Article and Find Full Text PDFMultiple myeloma (MM) is a clonal plasma cell malignancy typically associated with the high and uniform expression of the CD38 transmembrane glycoprotein. Daratumumab is a humanized IgG1κ CD38 monoclonal antibody (MoAb) which has demonstrated impressive single agent activity even in relapsed refractory MM patients as well as strong synergy with other anti-MM drugs. Natural Killer (NK) cells are cytotoxic immune effector cells that mediate in vivo tumour immunosurveillance.
View Article and Find Full Text PDFThe aim of the present work was to formulate a self-microemulsifying drug delivery system (SMEDDS) containing orlistat. The oil, surfactant and co-surfactant were decided based on the solubility studies. Pseudoternary phase diagrams were plotted, microemulsification area was determined and different formulations were prepared.
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