Biomedical subjects

Shyamapada Banerjee

Publications and source records attributed to Shyamapada Banerjee.

3 recordsLinked to original sources

PubMed2005

Convenient route to both enantiomers of a highly functionalized trans-disubstituted cyclopentene. Synthesis of the carbocyclic core of the nucleoside BCA.

[structures: see text] Synthesis of both enantiomers of a highly functionalized cyclopentenol derivative, versatile building block for a vast array of biologically active compounds, is described. The key steps involve stereocontrolled synthesis of a diene with two syn-disposed substituents from a (R)-(+)-glyceraldehyde derivative, ring-closing metathesis of this diene, and functional group manipulation of the resulting trans-disubstituted cyclopentene. One of the enantiomers of the cyclopentenol thus obtained has been converted to an amino cyclopentene, the carbocyclic core of the nucleoside (-)-BCA, a potent inhibitor of HIV reverse transcriptase.

Adenine↗

PubMed2003

Intramolecular [2 + 2] photocycloaddition of alkenes incorporated in a carbohydrate template. Synthesis of enantiopure bicyclo[3.2.0]heptanes and -[6.3.0]undecanes.

Intramolecular [2 + 2] photocycloaddition of alkenes with a furano sugar placed between them have been investigated under both copper(I)-catalyzed and sensitized conditions. The copper(I)-catalyzed photocycloaddition of the dienes 4a, 4b, and 4c led to unexpected formation of the thermodynamically less stable cis-syn-cis 4-5-5 tricyclic adducts 5a, 5b, and 5c, respectively. The sensitized photocycloaddition of the diene 14 also gave the cis-syn-cis adduct 15 showing that the copper(I) catalyst does not have any influence on the stereochemical course through coordination with the anomeric ring oxygen of the furano sugar. The identical stereochemical course observed under both catalyzed and sensitized photoaddition reactions have been attributed to be of steric origin. Bis(dienes) 25a and 25b, which gave an intractable mixture on copper(I)-catalyzed irradiation, underwent smooth photocycloaddition in the presence of benzophenone, and the resulting 1,2-divinyl cyclobutanes underwent spontaneous [3.3]-rearrangement at room temperature to produce bicyclo[6.3.0]undecanes 30a and 30b, respectively. This investigation provides an approach for the construction of enantiopure bicyclo[3.2.0]heptanes and -[6.3.0]undecanes.

Journal Article↗

PubMedDate not supplied

Splenunculus masquerading as colonic malignancy.

A 60-year-old woman presented with a hard lump of 5 x 3 cm in the left hypochondrium of 4 months duration. Clinical evaluation and investigations pointed towards a probably malignant colonic growth near the splenic flexure. She underwent an exploratory laparotomy with resection of the lump with the associated colon. Histopathology proved it to be a splenunculus. The rarity of such a case is highlighted and the diagnostic challenge it poses is discussed.

Abdominal Neoplasms↗