An efficient method for the synthesis of acylals from aldehydes using silica-supported perchloric acid (HClO4–SiO2)
作者:Vinod T. Kamble、Vasant S. Jamode、Neeta S. Joshi、Ankush V. Biradar、Rameshchandra Y. Deshmukh
DOI:10.1016/j.tetlet.2006.05.125
日期:2006.7
The synthesis of acylals from structurally diverse aldehydes has been performed in excellent yields under solvent-free conditions using HClO4–SiO2 as a mild, convenient, reusable, and heterogeneous catalyst. The procedure is operationally simple, environmentally benign and has the advantage of enhanced atom utilization. Furthermore, the catalyst can be recovered simply and reused efficiently a number
HBF 4 -SiO 2 has been found to be an outstanding catalyst for the protection of carbonyl compounds as acylals under entirely solvent-free conditions. Some of the major advantages of this procedure are high yields, ease of operation, high chemoselectivity, high atom efficiency, and compatibility with other protecting groups.
Conversion of Aldehydes into Geminal Dicarboxylates (Acylals) Catalyzed by Lithium Tetrafluoroborate
作者:Norihiko Sumida、Kuniaki Nishioka、Tsuneo Sato
DOI:10.1055/s-2001-18774
日期:——
A variety of aldehydes react with acid anhydrides in the presence of a catalytic amount of lithium tetrafluoroborate to afford the corresponding geminal dicarboxylates (acylals) in good to excellent yields.
The invention relates to a method and compounds for the preparation of clevidipine butyrate, a very short acting hypertensive calcium antagonist, as well as the synthesis of these compounds useful for the preparation of clevidipine (also known as clevidipine butyrate). Moreover the invention also discloses polymorphic forms of clevidipine butyrate, useful for the preparation of pharmaceutical compositions, and processes to prepare them.
The present invention relates to depot preparations for the targeted release of an aldehyde together with two carboxylic acids, where the released aldehydes are organoleptic substances, specifically fragrances or flavorings, and these depot preparations are prepared by reacting aldehydes with carboxylic anhydrides.