Joo-Yong Yoon, Sang-gi Lee and Hyunik Shin Pages 657 - 674 ( 18 )
Pyrazole is the ubiquitous sub-structure of many natural products and biologically active compounds. In this respect, its regioselective synthesis drew a lot of attention from synthetic organic chemists, leading to the development of various regioselective modifications of the classical Knorr cyclocondensation reaction and alternative methods. This review covers the period of 2003 to the middle of 2009 on the regioselective synthesis of pyrazoles, which are categorized into four reaction types: (i) modified Knorr condensation reaction using 1,3-dicarbonyl surrogates; (ii) 1,3-dipolar cycloadditions approach; (iii) regioselective direct substitution reaction of the pyrazole ring system; and (iv) other methods.
Pyrazole, regioselective dipolar cycloaddition, regioselective condensation, regioselective cross-coupling
Chemical Development Division, LG Life Sciences Ltd./R, Daejon 305-380, Korea, Department of Chemistry and Nano Science (BK21), Ewha Womans University, Seoul 120-750, Korea.