2051-49-2Relevant articles and documents
A Semisynthetic Approach to New Immunoadjuvant Candidates: Site-Selective Chemical Manipulation of Escherichia coli Monophosphoryl Lipid A
D'Alonzo, Daniele,Cipolletti, Manuela,Tarantino, Giulia,Ziaco, Marcello,Pieretti, Giuseppina,Iadonisi, Alfonso,Palumbo, Giovanni,Alfano, Alberto,Giuliano, Mariateresa,De Rosa, Mario,Schiraldi, Chiara,Cammarota, Marcella,Parrilli, Michelangelo,Bedini, Emiliano,Corsaro, Maria M.
, p. 11053 - 11063 (2016)
A semisynthetic approach to novel lipid A derivatives from Escherichia coli (E. coli) lipid A is reported. This methodology stands as an alternative to common approaches based exclusively on either total synthesis or extraction from bacterial sources. It relies upon the purification of the lipid A fraction from fed-batch fermentation of E. coli, followed by its structural modification through tailored, site-selective chemical reactions. In particular, modification of the lipid pattern and functionalization of the phosphate group as well as of the sole primary hydroxyl group were accomplished, highlighting the unusual reactivity of the molecule. Preliminary investigations of the immunostimulating activity of the new semisynthetic lipid A derivatives show that some of them stand out as promising, new immunoadjuvant candidates.
One-pot electrochemical synthesis of acid anhydrides from alcohols
Kashparova,Papina,Kashparov,Zhukova, I. Yu.,Ilchibaeva,Kagan, E. Sh.
, p. 2733 - 2735 (2017/12/26)
One-pot indirect electrochemical oxidation of alcohols in the methylene chloride–aqueous solution of sodium hydrocarbonate two-phase system in the presence of potassium iodide, 4-acetylamino-2,2,6,6-tetramethylpiperidin-1-oxyl, and 2,6-lutidine results in
Reaction of dicarbonates with carboxylic acids catalyzed by weak Lewis acids: General method for the synthesis of anhydrides and esters
Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Dalpozzo, Renato,Marcantoni, Enrico,Melchiorre, Paolo,Sambri, Letizia
, p. 3489 - 3496 (2008/09/19)
The reaction between carboxylic acids (RCOOH) and dialkyl dicarbonates [(R1OCO)2O], in the presence of a weak Lewis acid such as magnesium chloride and the corresponding alcohol (R1OH) as the solvent, leads to the esters RCOOR1 in excellent yields. The mechanism involves a double addition of the acid to the dicarbonate, affording a carboxylic anhydride [(RCO)2O], R1OH and carbon dioxide. The esters arise from the attack of the alcohols on the anhydrides. Exploiting the lesser reactivity of tert-butyl alcohol in comparison with other alcohols, a clean synthesis of both carboxylic anhydrides and esters has been set up. In the former reaction, an acid/Boc2O molecular ratio of 2:1 leads to the anhydride in good to excellent yields, depending on the stability of the resulting anhydride to the usual workup conditions. In the latter reaction, stoichiometric mixtures of the acid and Boc2O are allowed to react with a twofold excess of a primary alcohol, secondary alcohol or phenol (R 2OH) to give the corresponding esters (RCOOR2). Purification of the products is particularly easy since all byproducts are volatile or water soluble. A very easy chromatography is required only in the case of nonvolatile alcohols. A broad variety of sensitive functional groups is tolerated on both the acid and the alcohol, in particular a high chemoselectivity is observed. In fact, no transesterification processes occur with the acid-sensitive acetoxy group and methyl esters. Georg Thieme Verlag Stuttgart.
