Combination of Transition Metals-(2,4-Pentanedionate) and P2O5 as a Regioselective Catalytic System for Nitric Acid Nitration of Ar-Himachalene

Abstract

A practical system of metals-(2,4-pentanedionate) (M(acac)n (M= Fe, Zn, Co and V)) and P2O5 in the pres- ence of HNO3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in mod- erate to high yields. Under mild conditions, the selectivity of nitration of 1 to 2 is excellent compared to the classical method using the nitro-sulphuric mixture HNO3/H2SO4, both mono- and di-nitro-ar-himachalene 2 and 3 are obtained. The reaction offers a very good method for the preparation of nitro-aromatic compounds and provides a useful entry to new functionalized terpenic products.