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 P 2 O 5 in the presence of HNO 3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in moderate 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 HNO 3 /H 2 SO 4 , 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.

The chemistry of the himachalenes and atlantones from Cedrus

“…When the reaction was performed in sulfuric acid medium, only the dinitrate compound was obtained. 129 Recently, similar results were obtained by a catalytic route. Catalytic nitration of ar-himachalene was studied with complexes based on transition metals.…”