Chemoselective Protection Of Aldehydes Research Articles

ChemInform Abstract: Tungstosulfonic Acid as an Efficient Solid Acid Catalyst for Acylal Synthesis for the Protection of the Aldehydic Carbonyl Group.

Tungstosulfonic acid (TSA) has been found to be an efficient solid acid catalyst for the protection of aldehydic carbonyl groups by geminal diacetate (acylal) formation following the nucleophilic addition of acetic anhydride under neat conditions as well as in a solvent. The TSA catalyst is fully characterized by infrared spectroscopy, wide-angle X-ray scattering analysis, and scanning electron microscopy with energy dispersive X-ray spectroscopy. The deprotection of acylals to corresponding aldehydes has also been investigated under the similar conditions. The catalyst can be reused seven times without a significant loss of activity. In addition, no chromatographic separations are needed to obtain the desired products. This method is a green approach for the chemoselective protection of aldehydes in the presence of ketones.

SiO2@FeSO4 NANO COMPOSITE AS NANOCATALYST FOR THE GREEN SYNTHESIS 1,1-DIACETATES FROM ALDEHYDES UNDER SOLVENT-FREE CONDITIONS

Aldehydes compounds selective converted to 1,1-diacetates as protective reagent with SiO 2 @FeSO 4 nano composite as effective nano catalyst at room temperature under solvent-free condition and acetic anhydride (Ac 2 O) as acetylation reagent. This method provides several advantages, such as low cost of the nano catalyst, high yields, short reaction time, chemoselective protection of aldehydes and operational simplicity. Aromatic and aliphatic, simple and conjugated aldehydes were protected with excellent yields. In addition, chemoselective reductive acetylation of aldehydes over ketones was achieved perfectly with the reagent at room temperature. Scheme 1. Synthesis of 1,1-diacetates from aldehydes.

P4VP-H2SO4-Catalyzed Chemoselective Protection of Aldehydes to Acylal Along with Deprotection Reactions

Poly(4-vinylpyridine)-supported sulfuric acid is an excellent reusable heterogeneous catalyst for the chemoselective synthesis of 1,1-diacetates(acylal) from aldehydes in dichloromethane at room temperature within a few minutes. The protection of salicyaldehyde generated an anhydro-dimer as single product under similar reaction conditions. The catalyst is equally applicable for the deprotection of acylal in acetonitrile. The catalyst was prepared by the wet impregnation technique.

Solvent-free chemoselective protection of aldehydes on the surface of alumina-sulfuric acid

Chemoselective protection of alkyl and aryl aldehydes has been accomplished through the formation of dioxolane on the surface of alumina-sulfuric acid under solvent-free conditions where dialkyl ketones, aryl alkyl ketones, and diaryl ketones remain intact.

ChemInform Abstract: Chemoselective Protection of Aldehydes in the Presence of Ketones Using RuPVP Complex as a Heterogeneous Catalyst.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chemoselective Protection of Aldehydes in the Presence of Ketones Using RuPVP Complex as a Heterogeneous Catalyst

Ruthenium(III)-polyvinyl pyridine (RuPVP) complex was prepared by refluxing a methanolic solution of polyvinyl pyridine and trihydrated ruthenium trichloride. RuPVP catalyst was characterized by Fourier transform–infrared and diffential scanning calorimetry–thermogravimetry (TG). The catalyst was used for chemoselective protection of aldehydes in the presence of a ketonic carbonyl group.

A Facile and Efficient Conversion of Aldehydes into 1,1-Diacetates (Acylals) using Iron(III) Fluoride as a Novel Catalyst

Aldehydes are smoothly converted into the corresponding 1,1-diacetates (acylals) in high yields in the presence of a catalytic amount (0.1 mol-%) of iron(III) fluoride at room temperature. The noteworthy features of the present system are shorter reaction times, chemoselective protection of aldehydes, and solvent-free conditions. The procedure is especially useful for large-scale syntheses as the catalyst is highly effective from the view of activity, selectivity, reusability, and economy in the preparation of 1,1-diacetates (acylals).

Pr(OTf)3 as an Efficient and Recyclable Catalyst for Chemoselective Thioacetalization of Aldehydes

Praseodymium triflate has been found to be an efficient and recyclable catalyst for chemoselective protection of aldehydes.

Neodymium Triflate as a Recyclable Catalyst for Chemoselective Thioacetalisation

Neodymium triflate has been found to be an efficient and recyclable catalyst for the chemoselective protection of aldehydes.

Montmorillonite K-10 Clay as an Efficient Solid Catalyst for Chemoselective Protection of Carbonyl Compounds as Oxathiolanes with 2-Mercaptoethanol

Montmorillonite K-10 clay has been found to be a mild and efficient solid catalyst for the protection of a variety of carbonyl compounds, such as oxathiolanes, with 2-mercaptoethanol in good to excellent yields. In addition, by using this catalyst, high chemoselective protection of aldehydes in presence of ketones has been achieved.

ChemInform Abstract: Sc(OTf)3, an Efficient Catalyst for Formation and Deprotection of Geminal Diacetates (Acylals); Chemoselective Protection of Aldehydes in Presence of Ketones.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Sc(OTf)3, an Efficient Catalyst for Formation and Deprotection of Geminal Diacetates (Acylals); Chemoselective Protection of Aldehydes in Presence of Ketones

Sc(OTf)₃, an Efficient Catalyst for Formation and Deprotection of Geminal Diacetates (Acylals); Chemoselective Protection of Aldehydes in Presence of Ketones

Ceric ammonium nitrate as a convenient catalyst for chemoselective thioacetalisation

A new, mild and chemoselective protection of aldehydes as 1,3-dithiolanes using ceric ammonium nitrate as a catalyst is described. High yields are obtained at room temperature even in the presence of ketones. While alicyclic ketones may also be protected at elevated temperature, aromatic and acyclic ketones remained uneffected.

ChemInform Abstract: Chemoselective Protection of Aldehydes as Dithioacetals in Lithium Perchlorate‐Diethyl Ether Medium. Evidence for the Formation of Oxocarbenium Ion Intermediate from Acetals.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chemoselective Protection of Aldehydes as Dithioacetals in Lithium Perchlorate-Diethyl Ether Medium. Evidence for the Formation of Oxocarbenium Ion Intermediate from Acetals.

Aldehydes and acetals were very efficiently converted to acyclic and cyclic dithioacetals in 5 M lithium perchlorate/diethyl ether (LPDE) medium at ambient temperature in high yields. Spectroscopic and other experimental evidences strongly suggest the formation of oxocarbenium ion intermediates from acetals in 5 M LPDE which subsequently reacted with thiols to give the dithioacetals. Under the same conditions keto- nes and their acetals also reacted, albeit very slowly compared to al- dehydes and acetals, to yield dithioacetals. The difference in their reactivity was successfully employed in the chemoselective dithioace- talization of aldehydes and acetals in the presence of ketones and their acetals

Amberlyst-15 as a Convenient Catalyst for Chemoselective Thioacetalization

Abstract A new, mild and chemoselective protection of aldehydes as 1,3-dithiolanes is described. High yields are obtained at room temperature even in the presence of ketones. Ketones may also be protected at elevated temperatures.