Expanding the Scope of a One-Pot Double Displacement Protocol to Access the All-Rare-Sugar-Containing Trisaccharide Unit of OX1.

Herein, we have explored a one-pot bis-triflation and regioselective displacement protocol with d-fucose 2,4-diol to access various rare 6-deoxy amino d-sugars. This strategy enabled the first total synthesis of the trisaccharide unit of OX1 strain containing d-perosamine and d-tomosamine. Installation of a 1,2- linkage and late-stage -formylation are the key challenges in the total synthesis, which was accomplished via the longest linear sequence of 21 steps with 1.

Total Synthesis of O43 Tetrasaccharide Repeating Unit.

is a pathogen responsible for the deadly pandemic - cholera. The glycans present on the surface of various strains of are considered as potential vaccine candidates. The tetrasaccharide repeating unit (RU) of O43 is decorated with less-explored rare deoxy amino sugars like d-quinosamine and d-viosamine, along with a rare amino acid, -acetyl-l-allothreonine.

Total Synthesis of a Structurally Complex Tetrasaccharide Repeating Unit of O43.

Herein we report the first total synthesis of a densely functionalized tetrasaccharide repeating unit of O43, which contains rare deoxy amino sugars d-quinovosamine and d-viosamine attached with the rare amino acid -acetyl-l-allothreonine. Synthesis of orthogonally protected rare sugars and unnatural amino acid building blocks, stereoselective construction of three consecutive 1,2- glycosidic linkages, amide coupling, and the presence of five nitrogen atoms dispersed over four sugar units as well as the carboxylic acid functionality make the total synthesis a formidable task.

Frontal assessment battery in Parkinson's disease: A study on 170 patients.

Background: Frontal assessment battery (FAB) was devised as a specific study design to assess frontal lobe dysfunction. Since Parkinson's disease (PD) is often associated with cognitive and other higher mental function complications, FAB test has been carried out by a number of workers to assess the integrity of the frontal lobe. On the other hand, the other frequently conducted test, performed in order to evaluate the mental status, is the Mini Mental State examination of Folstein (MMSE), but its reliability has been questioned in PD, since it does not assess the functions of the frontal lobe alone.