The Experts below are selected from a list of 6714 Experts worldwide ranked by ideXlab platform
Fernando Iglesiasguerra - One of the best experts on this subject based on the ideXlab platform.
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stereoselective synthesis of Oxazolidines from 2 amino 2 deoxy d allose derivatives and their reactivity with nucleophiles
Tetrahedron-asymmetry, 2001Co-Authors: Jose M Vegaperez, Margarita Vega, Eugenia Blanco, Fernando IglesiasguerraAbstract:Abstract The use of 2-amino-2-deoxy- d -allose in the synthesis of Oxazolidines is described. The reaction takes place with total stereoselectivity in the preparation of both simple Oxazolidines (from aldehydes as reagent) and bicyclic Oxazolidines (from chlorocarbonyl compounds and keto-acids as reagents). The reactivity of the obtained Oxazolidines with hydride and alkylmagnesium chlorides is also described.
Mohamed K Mokhallalati - One of the best experts on this subject based on the ideXlab platform.
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1 2 vs 1 4 addition of nucleophilic organometallics to nonracemic 2 1 naphthyl and 2 cinnamyl 1 3 Oxazolidines
Journal of Organic Chemistry, 1992Co-Authors: Lendon N Pridgen, Mohamed K MokhallalatiAbstract:We herein report our results where the addition of organomagnesium reagents to 2-(1-naphthyl)- and 2-cinnamyl-1,3-Oxazolidines occurred consistently in a 1,4-conjugate manner, while lithium, cerium, and copper organometallic reagents added in a 1,2-fashion. The 1,4-conjugate addition pathway was primarily exploited by using (4R)-2-(1-naphthyl)-4-phenyl-1,3-oxazolidine (4) as a substrate to obtain, after NaBH 4 , reduction of the intermediate aldehyde, trans-disubstituted 1,2-dihydronaphthalenes with enantiomeric excesses of 93-94%
Sun Shuquan - One of the best experts on this subject based on the ideXlab platform.
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Environmentally Friendly and Regioselective One-Pot Synthesis of Imines and Oxazolidines Serinol Derivatives and Their Use for Rubber Cross-Linking
'American Chemical Society (ACS)', 2020Co-Authors: Barbera Vincenzina, Leonardi Gabriella, Valerio, Antonio Marco, Rubino Lucia, Sun Shuquan, Famulari Antonino, Galimberti Maurizio, Citterio Attilio, Sebastiano RobertoAbstract:High-yield regioselective synthesis of imines and Oxazolidines derivatives of 2-amino-1,3-propandiol (serinol) was achieved by performing the reaction with aldehydes and ketones, in the absence of solvents and catalysts. Only imines were obtained when the carbonyl compound was aromatic and/or sterically hindered and when conjugated double bonds were formed. 1,3-Oxazolidines were specifically obtained with either aldehydes or ketones with limited steric hindrance. The “green” reaction conditions here adopted for the synthesis of these classes of derivatives are not due to the structural and functional peculiarity of the serinol as a reactant and can also be extended to lipophilic amines with the same good results in terms of yield and selectivity. A revision of the mechanism typically accepted in the presence of solvent and catalysis is proposed, and the quantum mechanics calculations applied to some derivatives are in good agreement with the proposed rationalizations of the selectivity observed. Serinol itself and the imine and oxazolidine derivatives were used, in place of guanidine, as accelerators in compounds based on diene rubbers and silica, suitable for application in tire treads with low environmental impact. Efficient sulfur-based cross-linking and composites with a low dissipation of energy were obtained. The oxazolidine and imine appear to act as protective groups of the serinol primary amine. This work paves the way for the selective synthesis of biosourced families of chemicals, which could be used for large-scale applications, such as the one in rubber compounds, replacing toxic oil-based chemicals
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Serinol derivatives for the sustainable vulcanization of diene elastomers
'Rubber Division ACS', 2018Co-Authors: Barbera Vincenzina, Sun Shuquan, Citterio Attilio, Musto Sara, Infortuna Giuseppe, Cipolletti Valeria, Galimberti MaurizioAbstract:2-amino-1,3-propandiol (serinol) was used as the starting building block of synthetic pathways that led to the preparation of innovative chemicals suitable as ingredients for rubber compounds. Serinol based reactions were performed in the frame of a sustainable process, in the absence of any solvent and catalyst, with aldehydes and ketones, such as acetone, cinnamaldehyde and camphor. The synthesis of either imines or Oxazolidines was obtained with high selectivity. Serinol, imine and oxazolidine derivatives of serinol were used as accelerator for the vulcanization of diene rubbers. They were proved to be efficient secondary accelerators in silica based compounds based on poly(styrene-co-butadiene) in place of diphenyl guanidine. The kinetics of vulcanization was investigated for natural rubber based compounds in the absence of any filler. With respect to serinol, the imine derivatives were able to enhance the induction time of vulcanization and to afford a similar vulcanization rate
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Serinol: a biosourced building block for better mechanical reinforcement and sustainable vulcanization of rubber compounds
2017Co-Authors: Galimberti, Maurizio Stefano, Barbera Vincenzina, Citterio Attilio, Infortuna Giuseppe, Cipolletti, Valeria Rosaria, Sun ShuquanAbstract:Serinol and serinol derivatives were used to promote the mechanical reinforcement and the sulphur based crosslinking of rubber compounds. Reaction of serinol was performed with aldehydes and ketones, such as cinnamaldehyde, acetone, 2,5-hexanedione and camphor, obtaining the regiospecific synthesis of either imines or Oxazolidines. Paal-Knorr reaction was as well carried out between serinol and 2,5-hexanedione, obtaining a serinol derivative containing a pyrrole ring, 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol, named as serinolpyrrole. All the reactions were performed in the absence of solvents and catalysts and were characterized by high and also quantitative yields. Thanks to the reactions’ specificity, pure substances were obtained, with controlled atoms hybridization. The aromatic pyrrole ring was exploited to form adducts of serinolpyrrole with carbon allotropes. Adducts of SP with carbon black promoted the reduction of filler networking in silica based compounds. Serinol and immine as well oxazolidine derivatives were efficient secondary accelerators in silica based compounds and are thus suitable substances for the replacement of DPG. Tuning of vulcanization kinetics was performed
Barbera Vincenzina - One of the best experts on this subject based on the ideXlab platform.
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Environmentally Friendly and Regioselective One-Pot Synthesis of Imines and Oxazolidines Serinol Derivatives and Their Use for Rubber Cross-Linking
'American Chemical Society (ACS)', 2020Co-Authors: Barbera Vincenzina, Leonardi Gabriella, Valerio, Antonio Marco, Rubino Lucia, Sun Shuquan, Famulari Antonino, Galimberti Maurizio, Citterio Attilio, Sebastiano RobertoAbstract:High-yield regioselective synthesis of imines and Oxazolidines derivatives of 2-amino-1,3-propandiol (serinol) was achieved by performing the reaction with aldehydes and ketones, in the absence of solvents and catalysts. Only imines were obtained when the carbonyl compound was aromatic and/or sterically hindered and when conjugated double bonds were formed. 1,3-Oxazolidines were specifically obtained with either aldehydes or ketones with limited steric hindrance. The “green” reaction conditions here adopted for the synthesis of these classes of derivatives are not due to the structural and functional peculiarity of the serinol as a reactant and can also be extended to lipophilic amines with the same good results in terms of yield and selectivity. A revision of the mechanism typically accepted in the presence of solvent and catalysis is proposed, and the quantum mechanics calculations applied to some derivatives are in good agreement with the proposed rationalizations of the selectivity observed. Serinol itself and the imine and oxazolidine derivatives were used, in place of guanidine, as accelerators in compounds based on diene rubbers and silica, suitable for application in tire treads with low environmental impact. Efficient sulfur-based cross-linking and composites with a low dissipation of energy were obtained. The oxazolidine and imine appear to act as protective groups of the serinol primary amine. This work paves the way for the selective synthesis of biosourced families of chemicals, which could be used for large-scale applications, such as the one in rubber compounds, replacing toxic oil-based chemicals
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Serinol derivatives for the sustainable vulcanization of diene elastomers
'Rubber Division ACS', 2018Co-Authors: Barbera Vincenzina, Sun Shuquan, Citterio Attilio, Musto Sara, Infortuna Giuseppe, Cipolletti Valeria, Galimberti MaurizioAbstract:2-amino-1,3-propandiol (serinol) was used as the starting building block of synthetic pathways that led to the preparation of innovative chemicals suitable as ingredients for rubber compounds. Serinol based reactions were performed in the frame of a sustainable process, in the absence of any solvent and catalyst, with aldehydes and ketones, such as acetone, cinnamaldehyde and camphor. The synthesis of either imines or Oxazolidines was obtained with high selectivity. Serinol, imine and oxazolidine derivatives of serinol were used as accelerator for the vulcanization of diene rubbers. They were proved to be efficient secondary accelerators in silica based compounds based on poly(styrene-co-butadiene) in place of diphenyl guanidine. The kinetics of vulcanization was investigated for natural rubber based compounds in the absence of any filler. With respect to serinol, the imine derivatives were able to enhance the induction time of vulcanization and to afford a similar vulcanization rate
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Serinol: a biosourced building block for better mechanical reinforcement and sustainable vulcanization of rubber compounds
2017Co-Authors: Galimberti, Maurizio Stefano, Barbera Vincenzina, Citterio Attilio, Infortuna Giuseppe, Cipolletti, Valeria Rosaria, Sun ShuquanAbstract:Serinol and serinol derivatives were used to promote the mechanical reinforcement and the sulphur based crosslinking of rubber compounds. Reaction of serinol was performed with aldehydes and ketones, such as cinnamaldehyde, acetone, 2,5-hexanedione and camphor, obtaining the regiospecific synthesis of either imines or Oxazolidines. Paal-Knorr reaction was as well carried out between serinol and 2,5-hexanedione, obtaining a serinol derivative containing a pyrrole ring, 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol, named as serinolpyrrole. All the reactions were performed in the absence of solvents and catalysts and were characterized by high and also quantitative yields. Thanks to the reactions’ specificity, pure substances were obtained, with controlled atoms hybridization. The aromatic pyrrole ring was exploited to form adducts of serinolpyrrole with carbon allotropes. Adducts of SP with carbon black promoted the reduction of filler networking in silica based compounds. Serinol and immine as well oxazolidine derivatives were efficient secondary accelerators in silica based compounds and are thus suitable substances for the replacement of DPG. Tuning of vulcanization kinetics was performed
Jimmy Sélambarom - One of the best experts on this subject based on the ideXlab platform.
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A novel one-pot, two-step synthesis of N-acyl-1,3-thiazolidines and N-acyl-1,3-Oxazolidines as potential double prodrugs of formaldehyde
Tetrahedron Letters, 2011Co-Authors: Audrey Martinez, Jimmy SélambaromAbstract:A convenient and general one-pot, two-step protocol to prepare both N-acyl-1,3-thiazolidines and N-acyl-1,3-Oxazolidines from formaldehyde, fatty acyl chlorides, and natural α-amino acids has been performed for the peculiar case of formaldehyde. In the presence of triethylamine to promote both the ring-forming process and the amide bond formation, subsequent addition of the acyl donor proved to be efficient to trap the preformed stable formaldehyde-derived 1,3-thiazolidine or the transient 1,3-oxazolidine using an appropriate ratio of formaldehyde.
