A new and highly efficient synthesis of hydroxyporphyrins

摘要: Abstract A new synthesis of hydroxyporphyrins is reported. The method involves nucleophilic displacement a nitro group using the sodium salt E-benzaldoxime and general process allowing both β-hydroxyporphyrins meso-hydroxyporphyrins. Activation porphyrin system towards attack achieved by complexation macrocycle with relatively electronegative nickel(II) or copper(II) ions. Thus, treatment either chelates 2-nitro-5, 10,15,20-tetraphenylporphyrin gave corresponding 2-hydroxyporphyrin in high yield. Similar 5-nitro-2, 3,7,8,12,13,17,18-octaethylporphyrin 5-hydroxyporphyrin, again These reactions show that metallo-nitroporphyrins display similar electrophilic properties to much simpler nitro-arene systems. 5-hydroxyporphyrin 10 was cleanly demetallated on concentrated sulfuric acid give free-base oxophlorin thereby greatly increasing utility hydroxylation methodology. Conversion (5-methoxy-15-nitro-2,3,7,8,12,13,17,18-octaethylporphyrinato) 16 into (5-acetoxy-15-methoxy-2,3,7,8,12,13,17,18-octaethyl-porphyrinato) 18 established reaction mechanism regiospecific replacement (i.e., ipso-substitution) oxygen nucleophile.