Synthesis and X-ray crystallography of new N-, O-acyl pseudoephedrines

Abstract

N-acylation and O-acylation of pseudoephedrine are studied by using aroyl chlorides and/or ethyl chloroformate as acylating agents. Thus, treatment of pseudoephedrine or its salt with benzoyl or p-nitrobenzoyl chlorides affords the corresponding N- or O-acylated products 2a, b, 3a, b and 4. Also, pseudoephedrine 1 was allowed to react with ethoxymethylenemalononitrile to yield 2-hydroxy-1-methyl-2-phenylethyl](methyl)amino}methylene)malononitrile (5). New oxazolidine derivatives 6a–c were conveniently synthesized in high yields from the reaction of 1 with different bis(methylthio)yledinenitriles. X-ray crystallographic study of 4 revealed that the compound crystallized in orthorhombic system. The structure is stabilized by the intermolecular interactions as well as a network of hydrogen bond contacts, conformed parallel layers.

Graphical Abstract

Keywords:

• N-acylation
• O-acylation
• oxazolidines
• pseudoephedrine
• X-ray crystallography