Synthesis and crystal structure of 3-hydroxyclarithromycin and 2′-acetyl-3-oxo-clarithromycin

Clarithromycin was hydrolyzed in different conditions to form 3-hydroxyclarithromycin (2) and 3-hydroxy-8,9,10,11-dehydrous-9,12-hemiketal clarithromycin (3) respectively, then C(2′)-OH of 2 was protected with an acetyl group to yield 2′-acetyl-3-hydroxyclarithromycin (4), C(3)-OH of 4 was then oxidized by N-chlorosuccinimide (NCS) to yield 2′-acetyl-3-oxo- clarithromycin (5), and their structures were characterized by MS, IR, ¹H NMR and ¹³C NMR techniques. The crystal structures of 2 and 5 were determined by X-ray single crystal diffraction analysis, which belong to orthorhombic system with space group P2 ₁2 ₁2 ₁ and a= 13.657(3) nm, b= 14.783(3) nm, c= 16.510(3) nm, Z=4, V=3333.2(12) nm ³, D _c= 1.175 g/cm ³, F(000)=1288, μ=0.087 mm ^-1 (compound 2); a= 15.124(3) nm, 4=15.247(3) nm, c= 15.288(3) nm, Z=4, V=3525.4(12) nm ³,D _c= 1.187 g/cm ³, F(000)=1368.0, andμ=0.088 mm ^-1 (compound 5).