Benzyl 4-Phenylbutanoate is an intermediate in the synthesis of Namino-(3-[(R)-1-(3-(4-Amino-3-(4-phenoxyphenyl)- 1H-pyrazolo[3,4-d]pyrimidin-1-yl)piperidin-1-yl]-propionyl) Ibrutinib (A619015), which is an impurity of Ibrutinib (I124970), a highly selective Bruton's tyrosine kinase (Btk) irreversible inhibitor. Molecular Formula: C17H18O2 Solubility: Dichloromethane, Ether, Ethyl Acetate Molecular Weight: 254.32