- Tetrabutylammonium tribromide (TBATB): A mild and efficient catalyst for O-isopropylidenation of carbohydrates
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A wide range of O-isopropylidene derivatives can be prepared from the sugars and their derivatives on reaction with acetone at room temperature by employing 2 mol % of tetrabutylammonium tribromide (TBATB) as a catalyst. Good yields, low catalyst loading, mild reaction conditions, and a non-aqueous workup procedure are some major advantages of this protocol.
- Khan, Abu T.,Khan, Md. Musawwer,Adhikary, Anubendu
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Read Online
- Practical preparation of mono- and di-O-isopropylidene derivatives of monosaccharides and methyl 4,6-O-benzylidene glycosides from free sugars in a deep eutectic solvent
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Free sugars were rapidly converted into the corresponding di-O-isopropylidene derivatives and methyl O-benzylidene glycosides in excellent yields and purity in a deep eutectic solvent made from choline chloride and malonic acid (ChCl:MA). Reaction conditions were mild; work-up was easy, and further purification was not necessary. Given the inexpensive, nontoxic, and recyclable nature of ChCl:MA, this protocol is environmental friendly.
- Rokade, Sunil M.,Bhate, Prakash M.
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- Nano n-propylsulfonated magnetic γ-Fe 2O 3 as an efficient and reusable catalyst for the synthesis O-isopropylidene derivatives of carbohydrates
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Nano n-propylsulfonated γ-Fe2O3 was found to be a highly efficient, reusable heterogeneous catalyst for the conversion of a range of monosaccharides and some of their derivatives to the corresponding O-isopropylidene derivatives in good to excellent yields by refluxing the reaction mixture in dry acetone. The magnetic property of the catalyst enabled its separation from the reaction mixture by a simple process of filtration along with the aid of an external magnet. The efficiency of the catalyst was found to be largely unaffected for at least up to six cycles of reuse, thus proving the new methodology to be environmentally rewarding besides being simple and facile in operation.
- Zhang, Xiaoran,Zhang, Changqiang
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p. 249 - 258
(2013/08/15)
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- Organoiridium complexes: Efficient catalysts for the formation of sugar acetals and ketals
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[Cp*IrCl2]2 is used as an efficient promoter for the synthesis of sugar acetals and ketals with good to excellent yields. The catalyst is found to be general for a wide range of sugars.
- Mandal, Soumik,Verma, Prashant Ranjan,Mukhopadhyay, Balaram,Gupta, Parna
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experimental part
p. 2007 - 2010
(2011/12/01)
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- A simple and convenient synthetic protocol for O-isopropylidenation of sugars using bromodimethylsulfonium bromide (BDMS) as a catalyst
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Various O-isopropylidene derivatives of sugars and acyclic sugars were obtained in very good yields on reaction with acetone at room temperature with a catalytic amount of bromodimethylsulfonium bromide (BDMS). These O-isopropylidene derivatives can also be prepared in good yields on reaction with 2,2-dimethoxypropane (DMP) in acetonitrile using the same catalyst in shorter reaction times. Some of the advantages of this method are high effectiveness, a nonaqueous workup procedure, economic viability, and good yields.
- Khan, Abu T.,Musawwer Khan
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experimental part
p. 154 - 159
(2011/03/19)
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- Acetonation of l-pentoses and 6-deoxy-l-hexoses under kinetic control using heterogeneous acid catalysts
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The fibrous polymer-supported sulfonic acid catalyst Smopex-101 H+ proved to be an efficient catalyst for the preparation of O-isopropylidene derivatives from a series of rare sugars. Acetonation of the reducing sugars l-arabinose, l-ribose, l-xylose, l-fucose, and l-rhamnose in N,N-dimethylformamide by 2,2-dimethoxypropane or 2-methoxypropene led to the formation of the kinetically favored di-O- and/or mono-O-isopropylidene derivatives in 46-88% yields. The method consists of a simple experimental procedure which does not require predried solvents or reagents. The catalyst is easily recovered and can be regenerated making the procedure economically viable even for large-scale synthesis.
- Forsman, Jonas J.,Leino, Reko
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experimental part
p. 1548 - 1554
(2010/08/20)
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- Triphenylphosphine polymer-bound/iodine complex: A suitable reagent for the preparation of O-isopropylidene sugar derivatives
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O-Isopropylidene derivatives of sugars are readily prepared by using the Lewis acid and dehydrating agent triphenylphosphine polymer-bound/I2 complex. This new method is characterized by smooth, non-equilibrating reaction conditions and a very clean, simple work-up, making it particularly suitable for O-isopropylidenation of sugars under mild conditions and with low environmental impact. Georg Thieme Verlag Stuttgart.
- Pedatella, Silvana,Guaragna, Annalisa,D'Alonzo, Daniele,De Nisco, Mauro,Palumbo, Giovanni
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p. 305 - 308
(2007/10/03)
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- Sulfuric acid immobilized on silica: an efficient reusable catalyst for the synthesis of O-isopropylidene sugar derivatives
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Sulfuric acid immobilized on silica proved to be an efficient catalyst for the synthesis of O-isopropylidene sugar derivatives from reducing sugars. The method is very simple and economic for large-scale synthesis in which the catalyst is recovered and reused several times. Reactions with d-glucose, d-galactose, d-mannose, l-rhamnose, l-arabinose, d-xylose and l-sorbose led to the formation of the corresponding thermodynamically stable di-O- and/or mono-O-isopropylidene derivatives in good to excellent yields.
- Rajput, Vishal Kumar,Mukhopadhyay, Balaram
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p. 5939 - 5941
(2007/10/03)
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- Process for the preparation and separation of arabinose and xylose from a mixture of saccharides
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A process for the preparation and separation of the pentoses, xylose and arabinose from mixtures of saccharides by forming acetals is described. D-xylose is a precursor to xylitol, a sweetener, and L-arabinose is a precursor to the drug intermediate (R)-3,4-dihydroxybutyric acid, carnitine and agrichemicals.
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Page/Page column 3
(2008/06/13)
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- A new method of acetonation with the zeolite HY as catalyst. Synthesis of O-lsopropylidene sugar derivatives
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Zeolite HY proved to be a suitable catalyst for the acetonation of sugars. The method consists of a very simple and economic experimental procedure, in which the catalyst is recovered and can be regenerated. Reaction with D-galactose, L-arabinose, D-glucose, D-xylose, L-sorbose, D-glucofuranurono-6,3-lactone, D-ribose and its methyl glycoside led to the formation of di-O- and/or mono-O-isopropylidene derivatives in yields from 37-75%. Reaction with D-galactose and L-arabinose afforded the synthesis of the corresponding furanose derivatives as major products, together with minor quantities of the thermodynamically more stable pyranose derivatives. Acetonation of D-glucose, D-galactose, L-arabinose, D-xylose, L-sorbose, D-ribose, methyl β-D-ribofuranoside and D-glucofuranurono-6,3-lactone was performed by reaction with acetone using the zeolite HY as catalyst. Synthesis of O-isopropylidene derivatives was accomplished in moderate to good yields (37-75%). The method consists of a very simple and economic experimental procedure, in which the catalyst is recovered and can be regenerated. Reaction with D-galactose and L-arabinose afforded the synthesis of the corresponding di-O-isopropylidene and mono-O-isopropylidene furanose derivatives as major products, together with minor quantities of the thermodynamically more stable pyranose derivatives.
- Rauter, Amelia P.,Ramoa-Ribeiro, Fernando,Fernandes, Ana C.,Figueiredo, Jose A.
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p. 6529 - 6540
(2007/10/02)
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- ISOPROPYLIDENATION OF L-ARABINOSE N,N-DIMETHYLHYDRAZONE
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Direct isopropylidenation of L-arabinose N,N-dimethylhydrazone (I) was studied.Four major products whose structures were proven were produced in varying ratios depending upon the conditions. 2,2-Dimethoxypropane and sulfuric acid at 20 deg C gave a 36percent yield of 2,3:4,5-di-O-isopropylidene-L-arabinose N,N-dimethylhydrazone (II).Attempted aldol condensations directly on this hydrazone with paraformaldehyde were unsuccesful.This hydrazone was readily hydrolyzed to the corresponding protected aldehyde VI which underwent an aldol-Cannizzaro reaction to give the branched chain pentitol VII in high yield.
- Koos, Miroslav,Mosher, Harry S.
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p. 1994 - 1999
(2007/10/02)
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