Chitosan: an efficient promoter for the synthesis of 2-aminopyrimidine-5-carbonitrile derivatives in solvent free conditions

Siddiqui, I. R.; Rai, Pragati; Rahila, .; Srivastava, Anushree

doi:10.1039/c4nj00199k

Cited by 20 publications

(4 citation statements)

References 39 publications

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“…They offer considerable advantages toward the development of a more sustainable and greener chemistry, especially if they are promoted by renewable and biodegradable organocatalysts. In this context, significant results, reported before 2015, have been achieved in the multicomponent Strecker‐ and Biginelli‐type reactions. A sustainable Strecker reaction for the synthesis of α‐aminonitriles 6 by reacting aromatic aldehydes, amines, and trimethylsilyl cyanide (TMSCN) has been developed by exploiting raw commercially available chitosan as efficient heterogeneous organocatalyst to promote the one‐pot reaction at room temperature and under solvent‐free conditions (Scheme ) .…”

Section: Natural Polysaccharide‐based Organocatalystsmentioning

confidence: 95%

Valorization of Waste: Sustainable Organocatalysts from Renewable Resources

Meninno

2019

ChemSusChem

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443 Reviews Figure 2. Potential organocatalytic modes of activatione xhibited by chitosan.Scheme2.Monoglycerides ynthesis by ring opening of the glycidol catalyzed by chitosan. 444 ReviewsScheme3.Aldol reaction between 4-nitrobenzaldehyde (1)a nd cyclohexanone (2)promoted by chitosan hydrogel beads. Scheme4.Aldol reactionscatalyzed by dried chitosan gels and proposed catalytic modes of activation. 445 Reviews Scheme5.Aldol reaction in water promoted by chitosan aerogel beads (additivesu sed at 20 mol %: DNP = 2,4-dinitrophenol, SA = stearic acid, SDS = sodium dodecyl sulfate,B oc = tert-butyloxycarbonyl; ee = enantiomeric excess). Scheme6.Aldol reactionscatalyzedb yc hitosan in 1-butyl-3-methylimidazolium bromide ([bmim][Br])at3 78C. 446 Reviews Scheme16. Asymmetric aldol reaction in water catalyzedb yc hitosan-supported cinchonine. Scheme15. Chitosan-catalyzed transamidation of carboxamides with amines under neat conditions. 450 Reviews Scheme17. Knoevenagelcondensation of challenging aldehydes promoted by native and modified chitosan-derived hydrogels ([a] conversion valuesare reported). 458 Reviews Scheme33. Stereoselective Michael reaction catalyzedbyan aturalpinanederived bifunctional organocatalyst. Scheme32. Stereoselective Mannich reaction catalyzed by d-glucosamine-derived organocatalyst and the hypothetical reaction TS. 460 Reviews Scheme35. a) Synthesis of organocatalyst 52 derived from abietic acid. b) Asymmetric direct aldol reaction catalyzed by 52.c)Proposed TS model. 461 ReviewsScheme42. a) Reductive transformation of CO 2 with amines into formamidesand methylamines organocatalyzedbyl ecithin, and b) plausible reaction mechanism.

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Section: Natural Polysaccharide‐based Organocatalystsmentioning

confidence: 95%

Valorization of Waste: Sustainable Organocatalysts from Renewable Resources

Meninno

2019

ChemSusChem

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“…Chitosan (Figure 22) is synthesized by the basic hydrolysis of chitin (Polysaccharide) and well employed as organocatalyst in asymmetric syntheses. [128][129][130][131][132][133][134][135][136][137][138][139] In 2010, Ricci, Quignard and research group described the asymmetric direct aldol reaction of various ketone donars with p-nitrobenzaldehyde or isatin in presence of aerogel microsphere of chitosan 42 (Figure 22). Aldol products were obtained with high yields and good stereoselectivity (up to 93 % ee) (Scheme 21).…”

Section: Chitosan and Chitosan Derived Functionality As Organocatalys...mentioning

confidence: 99%

Growing Impact of Carbohydrate‐Based Organocatalysts

et al. 2022

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Organocatalysis has emerged as one of the most progressive and prevailing field of organic synthesis to assist green chemistry. Constantly increasing demand of promising scaffolds to develop potent organocatalysts has impelled researchers to utilize the unique traits of carbohydrate moiety in this field. Biological significance of carbohydrates, as well as, their high natural abundance as chiral non‐racemic material, presence of multiple hydroxyl groups, several stereogenic centres, and easily modifiable structure make this moiety an appropriate skeleton to develop organocatalysts to enhance productivity and selectivity of a chemical transformation. 21st Century has witnessed the progress of carbohydrate moiety in development of organocatalysts from obscurity to eminence. This review encapsulates the importance of carbohydrate scaffolds in organocatalysis mainly dealing with the synthesis and applications carbohydrate‐derived organocatalyst in different common organic reactions with their significance and future purspectives.

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“…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.…”

Section: Polysaccharidesmentioning

confidence: 99%

Synthesis and Applications of Carbohydrate-Based Organocatalysts

et al. 2021

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Organocatalysis is a very useful tool for the asymmetric synthesis of biologically or pharmacologically active compounds because it avoids the use of noxious metals, which are difficult to eliminate from the target products. Moreover, in many cases, the organocatalysed reactions can be performed in benign solvents and do not require anhydrous conditions. It is well-known that most of the above-mentioned reactions are promoted by a simple aminoacid, l-proline, or, to a lesser extent, by the more complex cinchona alkaloids. However, during the past three decades, other enantiopure natural compounds, the carbohydrates, have been employed as organocatalysts. In the present exhaustive review, the detailed preparation of all the sugar-based organocatalysts as well as their catalytic properties are described.

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Chitosan: an efficient promoter for the synthesis of 2-aminopyrimidine-5-carbonitrile derivatives in solvent free conditions

Cited by 20 publications

References 39 publications

Valorization of Waste: Sustainable Organocatalysts from Renewable Resources

Valorization of Waste: Sustainable Organocatalysts from Renewable Resources

Growing Impact of Carbohydrate‐Based Organocatalysts

Synthesis and Applications of Carbohydrate-Based Organocatalysts

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