Structure–activity relationship studies of the pyrazolo [1, 5-a] pyridine class of PI3 kinase inhibitors show that substitution off the hydrazone nitrogen and replacement of the sulfonyl both gave a loss of p110α selectivity, with the exception of an N-hydroxyethyl analogue. Limited substitutions were tolerated around the phenyl ring; in particular the 2, 5-substitution pattern was important for PI3 kinase activity. The N-hydroxyethyl compound also showed ...
