Ring-opening cyclization of activated spiro-aziridine oxindoles with heteroarenes: a facile synthetic approach to spiro-oxindole-fused pyrroloindolines

Herein, we report a facile tandem approach for the synthesis of both spiro-oxindole-fused pyrroloindolines and benzofurano-pyrrolidines via a Lewis acid-catalyzed domino ring-opening with concomitant ring annulation using activated spiro-aziridines and heteroarenes. This method offers a new class of novel spiro-fused polycyclic pyrrolidines in a one-pot and sustainable manner with good yields and high diastereoselectivity. In addition, the structure of 3d was confirmed by single X-ray crystallography analysis.

Herein, we report a facile tandem approach for the synthesis of both spiro-oxindole-fused pyrroloindolines and benzofurano-pyrrolidines via a Lewis acid-catalyzed domino ring-opening annulation using activated spiro-aziridines and heteroarenes.     

Iodine-mediated C–N and N–N bond formation: a facile one-pot synthetic approach to 1,2,3-triazoles under metal-free and azide-free conditions

A novel strategy towards the synthesis of 1,4-disubstituted 1,2,3-triazoles via C–N and N–N bond formation has been demonstrated under transition metal-free and azide-free conditions. These 1,2,3-triazoles were obtained in a regioselective manner from commercially available anilines, aryl alkenes/aryl alkynes and N-tosylhydrazines using I₂ under O₂ atmosphere. Broad substrate scope, milder reaction conditions, good to moderate yields and clean protocol are the notable features of the method. Moreover, this protocol is amenable for the generation of a library of medicinally important key building blocks.

A novel strategy towards the synthesis of 1,4-disubstituted 1,2,3-triazoles via C–N and N–N bond formation has been demonstrated under transition metal-free and azide-free conditions.     

TCCA-mediated oxidative rearrangement of tetrahydro-β-carbolines: facile access to spirooxindoles and the total synthesis of (±)-coerulescine and (±)-horsfiline

Multi-reactive centered reagents are beneficial in chemical synthesis due to their advantage of minimal material utilization and formation of less by-products. Trichloroisocyanuric acid (TCCA), a reagent with three reactive centers, was employed in the synthesis of spirooxindoles through the oxidative rearrangement of various N-protected tetrahydro-β-carbolines. In this protocol, low equivalents of TCCA were required to access spirooxindoles (up to 99% yield) with a wide substrate scope. Furthermore, the applicability and robustness of this protocol were proven for the gram-scale total synthesis of natural alkaloids such as (±)-coerulescine (1) and (±)-horsfiline (2) in excellent yields.

Three-reactive centered reagent (TCCA) mediated construction of spirooxindoles through an oxidative rearrangement of various N-protected tetrahydro-β-carbolines and total synthesis of natural alkaloids (±)-coerulescine and (±)-horsfiline.     

Evaluation of Cyst Fluid CEA Analysis in the Diagnosis of Mucinous Cysts of the Pancreas

Background  

Although cyst fluid carcinoembryonic antigen (CEA; >192 ng/ml) is the preferred test for identifying mucinous pancreatic cysts, the data are more robust for mucinous cystic neoplasms (MCN) than for intraductal papillary mucinous neoplasms (IPMN). The role of cyst fluid CEA as a marker for either malignancy or malignant progression is uncertain.