1.3.4.5- Tetrasubstituted pyrazoles synthesis

A new synthesis of pyrroles generates a 1,3-diketone by reacting a lithium enolate of a ketone with an acid chloride in situ addition of a hydrazine yields, potentially, a tetrasubstituted pyrazole.297 Tolerant of a wide range of functional groups, it is also easily adapted to rapid preparation of fused bicyclic pyrazole systems. 

Stauffer SR, Katzenellenbogen JA, Solid-phase synthesis of tetrasubstituted pyrazoles, novel ligands for the estrogen receptor, J. Comb. Chem., 2 318-329, 2000. 

A rapid and efficient synthesis of 1,3,4,5-tetrasubstituted pyrazoles 21 and 23 was disclosed by applying the previously established protocol for the... 

Scheme 8.65 Synthesis of tetrasubstituted pyrazoles from enamines and nitriles.

Multisubstituted pyrazoles commonly are difficult to prepare with conventional methods. The synthesis of a variety of high diversified tri- and tetrasubstituted... 

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