Amphoteric Amino Aldehydes Reroute the Aza-Michael Reaction
摘要:
Amphoteric amino aldehydes, which exist as stable dimers, participate in an aza-Michael/aldol domino reaction with alpha,beta-unsaturated aldehydes to afford stable 1,5-aminohydroxyaldehydes in high yields and diastereoselectivies. The reaction outcome hinges upon the dimeric nature of amphoteric amino aldehydes and the orthogonality between the NH aziridine and the two aldehyde functionalities during the reaction. Through the use of reaction conditions that disfavor dimer dissociation, the aza-Michael process has been directed toward a novel 8-(enolendo)-exo-trig cyclization. The results described herein further demonstrate the potential of amphoteric molecules in reaction discovery.
METHODS FOR THE SYNTHESIS OF SPHINGOMYELINS AND DIHYDROSPHINGOMYELINS
申请人:CERENIS THERAPEUTICS HOLDING SA
公开号:US20140316154A1
公开(公告)日:2014-10-23
The present invention includes methods for the synthesis of sphingomyelins and dihydrosphingomyelins. The present invention also includes methods for the synthesis of sphingosines and dihydrosphingosines. The present invention further includes methods for the synthesis of ceramides and dihydroceramides.
A process for the preparation and/or purification of clavulanic acid or a pharmaceutically acceptable salt or ester thereof comprises
i) contacting impure clavulanic acid or an alkali metal salt thereof in an organic solvent, with an amine of formula (II)
where R¹ is a group of general formula
where R⁴ and R⁵ are independently hydrogen, alkyl, amino-substituted alkyl or substituted amino-substituted alkyl, and R² and R³ are independently selected from hydrogen, alkyl, amino- or hydroxy-substituted alkyl or substituted amino-substituted alkyl, and m is zero or an integer 1 to 5;
ii) isolating the amine salt of clavulanic acid formed;
iii) converting the thus formed salt into clavulanic acid or a pharmaceutically acceptable salt or ester thereof.
A process for the preparation of clavulanic acid or its pharmaceutically acceptable salts and esters in which an amine of formula (II):
is used as an intermediate to form a salt with clavulanic acid, R1, R2 and R3 being selected from various substituent atoms and groups.
(EN) A back extraction process in which beta-lactam antibiotics or clavulanic acid is extracted from an organic solvent phase into an aqeous medium phase, using a mixing region in which the phases are mixed rapidly under high turbulence and shear stress.(FR) Procédé de réextraction, selon lequel des antibiotiques du type bêta-lactamines ou de l'acide clavulanique sont extraits d'une phase de solvant organique sous forme de phase aqueuse, et consistant à utiliser une zone de mélange dans laquelle ces phases sont rapidement mélangées sous l'effet d'une turbulence et d'une contrainte tangentielle élevées.