4-{1-[3-cyanomethyl-1-(ethylsulfonyl)azetidine-3-yl]-1H-pyrazol-4-yl}pyrimidine-5-carbonitrile ; Baricitinib Impurity-G;Baricitinib Impurity 17;5-Pyrimidinecarbonitrile, 4-[1-[3-(cyanomethyl)-1-(ethylsulfonyl)-3-azetidinyl]-1H-pyrazol-4-yl]