scholarly journals Technological Aspects of Highly Selective Synthesis of Allyloxyalcohols—New, Greener, Productive Methods

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1559
Author(s):  
Magdalena Urbala
Keyword(s):  
Allyl Chloride ◽  
Industrial Applications ◽  
Solvent Free ◽  
Pt Catalyst ◽  
Hydroxyl Groups ◽  
Equimolar Ratio ◽  
Allyl Ethers ◽  
Solvent Free Conditions ◽  
Free Hydroxyl ◽  
By Products

Allyl ethers bearing free hydroxyl groups of CH2=CH-CH-O-A-OH type (hydroxyalkyl allyl ethers, allyloxyalcohols) are valuable chemicals in many environmentally friendly industrial applications. The development of technologically attractive methods for their production is necessary. The two pathways (L-L PTC and non-catalytic solvent-free conditions) were optimized for the highly selective and yield synthesis of 4-allyloxybutan-1-ol. Improvements in the PTC method (50% NaOH(aq), the equimolar ratio of NaOH to diol, cyclohexane as solvent) with a new highly selective and effective PT catalyst, i.e., Me(n-Oct)3N+Br− (0.3 mol%), resulted in 88% yield and 98% selectivity of 4-allyloxybutan-1-ol with minimal formation of allyl chloride hydrolysis by-products (<1%). In turn, application of non-catalytic solvent-free conditions and the change in the key substrate with an excess of diol and use of solid NaOH solely led to a mono-O-allylation product with an excellent yield of 99% in a relatively short reaction time (3.5 h), with trace amounts of by-products (<0.1%). This sustainable method is perfectly suitable for the synthesis on a larger scale (3 moles of the key substrate) and for the full O-allylation process.

An efficient method for the silylation of hydroxyl groups with hexamethyldisilazane (HMDS) catalyzed by aluminum tris(dihydrogen phosphate) under solvent-free and ambient conditions

2008 ◽  
Vol 86 (8) ◽  
pp. 841-845 ◽  
Author(s):  
Hamid Reza Shaterian ◽  
Majid Ghashang ◽  
Nassrin Tajbakhsh Riki ◽  
Manijeh Asadi
Keyword(s):  
Heterogeneous Catalyst ◽  
Efficient Method ◽  
Room Temperature ◽  
Solvent Free ◽  
Dihydrogen Phosphate ◽  
Hydroxyl Groups ◽  
Ambient Conditions ◽  
Solvent Free Conditions ◽  
Free Hydroxyl ◽  
Recyclable Heterogeneous Catalyst

A highly efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, benzylic, secondary, hindered secondary, tertiary, phenols, and oximes with hexamethyldisilazane (HMDS), using Al(H2PO4)3 as a recyclable heterogeneous catalyst at room temperature in a few minutes with excellent yields under solvent-free conditions is described.Key words: trimethylsilylation, hexamethyldisilazane, aluminum tris(dihydrogen phosphate) [Al(H2PO4)3], solvent-free, hydroxyl groups.

scholarly journals Highly Productive Synthesis of 1-Propenyloxybutan-1-ol Under Solvent-Free Homogeneous Ruthenium Catalyst Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1409
Author(s):  
Magdalena Urbala
Keyword(s):  
Ruthenium Catalyst ◽  
Solvent Free ◽  
Hydroxyl Groups ◽  
High Catalytic Activity ◽  
Reaction Conditions ◽  
Oxidative Reaction ◽  
Environmentally Sustainable ◽  
Reactive Diluents ◽  
Solvent Free Conditions ◽  
Free Hydroxyl

The 1-propenyl ethers bearing free hydroxyl groups of CH3CH=CH–O–A–OH type (hydroxyalkyl 1-propenyl ethers, 1-propenyloxyalcohols) are the most desired as the reactive diluents for photopolymerizable systems with enhanced reactivity or intermediates for the synthesis of hybrid monomers for special applications. The ruthenium complexes-catalyzed isomerization of allyl ethers under solvent-free conditions is an atom-economical and environmentally sustainable method for their production. Here, the reaction conditions and limitations for the highly productive and selective synthesis of model 4-(1-propenyloxy)butan-1-ol have been investigated. The minimal loading of ruthenium pre-catalysts needed for completion of reaction within reasonable times was priority assumption. It was found that [RuClH(CO)(PPh3)3] or [RuCl2(PPh3)3] exhibited extremely high catalytic activity under optimized non-oxidative reaction conditions. The key effect of reaction temperature on the activation pre-catalyst and the exothermal effects of isomerization was discovered. The practically quantitative yields of 4-(1-propenyloxy)butan-1-ol were achieved with using of very low loading of [Ru] (5 ppm) and Bu3N (to maintain reaction chemoselectivity) at the temperature of 120 °C for only 0.5 h. Consequently, the attained TON (turnover number) and TOF (turnover frequency) values of ca. 198,000 and 390,000 h−1 were unprecedentedly high and industrial attractive. On the other hand, the direct recycling of ruthenium catalyst is not a reasonable method for improving catalyst productivity.

scholarly journals Magnetic Fe3O4@silica sulfuric acid nanoparticles promoted regioselective protection/deprotection of alcohols with dihydropyran under solvent-free conditions

RSC Advances ◽  
2017 ◽  
Vol 7 (89) ◽  
pp. 56559-56565 ◽  
Author(s):  
Kalyani Rajkumari ◽  
Juri Kalita ◽  
Diparjun Das ◽  
Lalthazuala Rokhum
Keyword(s):  
Sulfuric Acid ◽  
Sulphuric Acid ◽  
Catalytic Amount ◽  
Solvent Free ◽  
Hydroxyl Groups ◽  
Silica Sulfuric Acid ◽  
Solvent Free Conditions ◽  
Magnetic Fe3o4

Protection (and deprotection) of hydroxyl groups via tetrahydropyranylation was carried out effectively using a catalytic amount of Fe3O4 supported silica sulphuric acid nanoparticles (Fe3O4@SiO2@SO3H) under solvent-free conditions.

scholarly journals Microwave Assisted Efficient Synthesis of Flavone using ZnO Nanoparticles as Promoter under Solvent-Free Conditions

2019 ◽  
Vol 31 (5) ◽  
pp. 1133-1136
Author(s):  
Pradip J. Unde ◽  
Nitin M. Thorat ◽  
Limbraj R. Patil
Keyword(s):  
Zno Nanoparticles ◽  
Solvent Free ◽  
Alternative Route ◽  
Efficient Synthesis ◽  
Short Reaction Time ◽  
Microwave Assisted ◽  
Solvent Free Conditions ◽  
The Stability ◽  
Work Up ◽  
By Products

A simple and highly efficient protocol for synthesis of flavones from 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in presence of ZnO nanoparticles as a promoter in thermal as well as microwave irradiation under solvent-free conditions have been demonstrated. The catalyst is inexpensive, stable, can be easily recycled/reused for several cycles with consistent activity and observed almost same yield confirming the stability of the catalyst. It is believed that the present approach will become an alternative route for the conventional reactions. Because in this protocol, yield is quite high, short reaction time, simple work up, catalyst can be recycled as well as it is free of any hazardous by-products formation during workup.

scholarly journals Multisulfonate hyperbranched polyglycerol functionalized graphene oxide as an efficient reusable catalyst for green synthesis of benzo[a]pyrano-[2,3-c]phenazines under solvent-free conditions

RSC Advances ◽  
2019 ◽  
Vol 9 (13) ◽  
pp. 7400-7410 ◽  
Author(s):  
Hossein Naeimi ◽  
Maryam Farahnak Zarabi
Keyword(s):  
Graphene Oxide ◽  
Green Synthesis ◽  
Acid Catalyst ◽  
Solvent Free ◽  
Reusable Catalyst ◽  
Hydroxyl Groups ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Solvent Free Conditions ◽  
Hyperbranched Polyglycerol

A novel acid catalyst was prepared based on growing hyperbranched polyglycerol (HPG) on the surface of graphene oxide. Then, the hydroxyl groups of HPG on graphene oxide were functionalized by sulfonate groups to form an acid catalyst.

(Carboxy-3-oxopropylamino)-3-propylsilylcellulose as a novel organocatalyst for the synthesis of substituted imidazoles under solvent-free conditions

RSC Advances ◽  
2015 ◽  
Vol 5 (43) ◽  
pp. 33974-33980 ◽  
Author(s):  
Mehri Salimi ◽  
Mohammad Ali Nasseri ◽  
Tayyebeh Daliran Chapesshloo ◽  
Batol Zakerinasab
Keyword(s):  
Solvent Free ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Solvent Free Conditions ◽  
Anchor Points

(Carboxy-3-oxopropylamino)-3-propylsilylcellulose (COPAPSC), a novel organocatalyst, has been prepared by a synthesis grafting of –COOH functionalized organosilanes on a cellulose using surface hydroxyl groups as anchor points.

scholarly journals Preparation of a set of selectively protected disaccharides for modular synthesis of heparan sulfate fragments: toward the synthesis of several O-sulfonated [β-D-GlcUA-(1→4)-β-D-GlcNAc]OPr types

2005 ◽  
Vol 3 (4) ◽  
pp. 803-829 ◽  
Author(s):  
Hammed Hassan
Keyword(s):  
Heparan Sulfate ◽  
Building Blocks ◽  
Protecting Groups ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Allyl Ethers ◽  
Modular Synthesis ◽  
Stereocontrolled Synthesis ◽  
Benzyl Ethers ◽  
Free Hydroxyl

AbstractA concise method for a stereocontrolled synthesis of a set of selectively protected disaccharides is reported. Coupling of the donor 11 onto acceptors 23 and 24, promoted by trimethylsilyl triflate-N-iodosuccinimide (TMSOTf-NIS), generated the disaccharides 25 and 26. Under typical conditions, condensation of the fully protected donor 12 onto acceptors 23 and 24 produced the disaccharides 27 and 28. The building blocks 25–28 were prepared in moderate yields having exclusive β-stereoselectivity. A unique pattern of protecting groups distinguished clearly between positions to be sulfated and functional groups remaining as free hydroxyl groups. Acetyl and/or levulinoyl esters temporarily protected the positions to be sulfated, while benzyl ethers were used for permanent protection. The anomeric positions were protected as allyl ethers, whereas the 4′-positions were masked as p-methoxybenzyl (PMB) ethers. The orthogonality of the PMB and allyl groups can then be used for further elongation of the chain by recurrent deprotection and activation steps. The hydroxyl group, OH-6, of glucosamine moieties was protected as a TBDPS ether to avoid oxidation. A five-step deprotection/sulfonation sequence was applied to the disaccharide 27 to generate the corresponding sulfated [β-D-GlcUA-2-OSO3Na-(1→4)-β-D-Glc pNAc]-(1→O-Pro) 34.

Epoxidation of Allyl Chloride to Epichlorohydrin by a Reversible Supported Catalyst with H2O2under Solvent-Free Conditions

2006 ◽  
Vol 10 (5) ◽  
pp. 876-880 ◽  
Author(s):  
Jun Li ◽  
Gongda Zhao ◽  
Shuang Gao ◽  
Ying Lv ◽  
Jian Li ◽  
...  
Keyword(s):  
Allyl Chloride ◽  
Supported Catalyst ◽  
Solvent Free ◽  
Solvent Free Conditions

scholarly journals A Green and Facile Method for the Synthesis of Substituted 1,2-Epoxy Ethylgembisphosphonates and their Symmetrical Dibutylammmonium Salts

2020 ◽  
Author(s):  
Siphamandla B Simelane ◽  
Derek T Ndinteh ◽  
Xavier Y Mbianda
Keyword(s):  
Hydrogen Peroxide ◽  
Environmentally Friendly ◽  
Solvent System ◽  
Solvent Free ◽  
Easy Access ◽  
Water Solvent ◽  
Solvent Free Conditions ◽  
Environmentally Friendly Method ◽  
By Products

In this paper we report a convenient and environmentally friendly method for the synthesis of substituted 1,2-epoxy ethylgembisphosphonates using hydrogen peroxide in methanol-water solvent system. This reaction allows easy access to the desired epoxy bisphosphonates in good to excellent yields. It can also be scaled up easily since it requires small amounts of solvents and there are no by-products. The epoxy bisphosphonates were dealkylated with dibutylamine under solvent-free conditions to give novel symmetrical dibutylammonium diethyl (oxirane-2,2-diyl)bisphosphonate salts.

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