Synthesis of New Optically Active d-Glucosamine-Pyrrole Derivatives

Abstract

From D-glucosamine hydrochloride was synthesized, for the first time, three new optically active derivatives of D-glucosamine-pyrrole with the pyrrole group unsubstituted in the 2-and 5-positions. New N-benzylpyrrole-D-glucosamine derivatives were also prepared from the same substrate.

Catalyst‐ and Supporting‐Electrolyte‐Free Electrosynthesis of Benzothiazoles and Thiazolopyridines in Continuous Flow

“…Alkyl and aryl thioamides reacteds moothly with good yields (3-6, 9-17, 20, 22). Many functional groups were tolerated in the electrochemical oxidation, such as free alcohols (14,21), silyl ethers (15), esters (16,20), carbamates (17), sulfonamides ( 17,22)a nd phosphineo xides (24). The cyclization to benzothiazole could also be obtained with other 2-substituents, such as heteroaryl (29)a nd electron-rich arenes (6).…”

“…Organic electrosynthesis is known as an alternative method of performing redoxp rocesses, in which toxic or dangerous oxidizingo rr educing reagents are replaced by electrons, making such processes more environmentally friendly than traditional methods employing stoichiometric redox reagents. [16][17][18][19][20][21] Therea re an umber of examples of electrochemical methods to achieve CÀHf unctionalization. [22][23][24][25][26][27][28] We have recently developed electrochemical reactions to synthesize Nheterocycles through creating new CÀNb onds, [29,30] and some of these methods use am ediator such as 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO) [31] or ferrocene [32,33] to perform the oxidation of the substrate.…”

Experimental and Theoretical Evidence of a Persistent Radical-Cation Dimer Generated during the Electrooxidation of an N-Glucosamine-pyrrole Derivative

“…An important factor that should limit the formation of higher oligomers is the sterical hindrance of the acetate groups during the process. In the Py-GSATA monomer crystal structure, in the neutral (Figure a) and the radical-cation species (Figure b), the pyrrole group shows a conformation perpendicular to the sugar plane as a response to the bulky acetate groups. When the dication σ-dimer is formed, the sterical hindrance of acetate groups on pyrrole groups is extremely high.…”

“…1,3,4,6-Tetra- O -acetyl-2-(pyrro-1-yl)-2-deoxy-β- d -glucopyranose (Py-GSATA) (Figure ) was prepared as described in the literature . Anhydrous acetonitrile (CH 3 CN, ACN) was used as received, handling the sealed bottle under positive N 2 pressure.…”

“…Interested in the electrosynthesis of chiral conducting polymers, we studied the electrochemical response of 1,3,4,6-tetra- O -acetyl-2-amino-2-deoxy-2-(pyrro-1-yl)-β- d -glucopyranose ( 1 ) (Py-GSATA, Figure ) . This compound showed clear oxidation processes that corresponded to the pyrrole oxidation.…”