[4-(1H-Pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl]methyl 2,2-dimethylpropanoate ; [4-(1H-Pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl]methyl pivalate;Propanoic acid, 2,2-dimethyl-, [4-(1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl]methyl ester