1-Pyrrolidinecarboxylic acid, 3-[2-[(ethoxycarbonyl)[5-[(4-methylphenyl)sulfonyl]-5H-pyrrolo[2,3-b]pyrazin-2-yl]amino]acetyl]-4-ethyl-, phenylmethyl ester, (3R,4S)-rel- [ 1869118-27-3 ]