Chitosan: a sustainable, reusable and biodegradable organocatalyst for green synthesis of 1,4-dihydropyridine derivatives under solvent-free condition

A functional chitosan-based hydrogel as a wound dressing and drug delivery system in the treatment of wound healing

“…They include increased exudate absorption capacity, enhanced adherent and anti-bacterial capacity, stimulation of angiogenesis and reepithelialization of skin tissue and collagen deposition, and sustained delivery of drugs. 50,51 In addition, as DDS, due to its unique properties, chitosan is a suitable polymer for the delivery of other active ingredients, such as drugs, growth factors, stem cells, peptides and etc., to provide a therapeutic payload that can be more effective in the treatment of local wounds. 52 The main achievements obtained recently regarding chitosan-based hydrogels as wound dressings or DDS for wound healing will be discussed in the following part.…”

Synthesis and Applications of Carbohydrate-Based Organocatalysts

“…Thus, chitosan-based organocatalysts were employed in Knoevenagel [ 204 , 205 , 206 , 207 , 208 , 209 ] and aldol reaction [ 204 , 205 , 210 , 211 ], three-component reactions [ 212 , 213 , 214 ], aldehyde self-condensation [ 215 , 216 ], epoxide opening reactions [ 217 , 218 ], Strecker reaction [ 219 ], transamidation reaction [ 220 ], Petasis borono–Mannich reaction [ 221 ], Hantzsch-type condensation [ 222 ], in synthesis of dyes [ 223 ] and perimidines [ 224 ]. In addition to chitosan, also chitin [ 225 ] and modified cellulose [ 226 ] were employed to catalyse the Knoevenagel condensation.…”

Valorization of Waste: Sustainable Organocatalysts from Renewable Resources

“…In 2016, four‐component reactions of different aldehydes, dimedone 7 , β‐ketoesters or acetoacetanilide 8 , and ammonium acetate were reported for the synthesis of 1,4‐dihydropyridine derivatives 9 (Scheme ) . The reaction was promoted by commercially available high‐molecular‐weight chitosan from shrimp shells (MW 310–375 kDa, >75 % DDA) at 60 °C under solvent‐free conditions.…”

“…In 2016, four-component reactions of different aldehydes, dimedone 7, b-ketoesters or acetoacetanilide 8,a nd ammonium acetate were reported for the synthesis of 1,4-dihydropyridine derivatives 9 (Scheme9). [46] Ther eaction was promoted by commerciallya vailable high-molecular-weight chitosanf rom shrimps hells( MW 310-375kDa, > 75 %D DA) at 60 8Cu nder solvent-free conditions. The Hantzsch-type condensation affordedh eterocyclic products 9 in high yields and the biopolymer was recyclable and reused up to nine times without observing reduction of the catalytic activity.…”