Complex sentence: Krasnoshchyokov was held in the Lefortovo prison in Moscow, where he contracted pneumonia in November 1924 when he was transferred to the government hospital near the Kremlin.
Split into simpler sentences: Krasnoshchyokov was held in the Lefortovo prison in Moscow, where he contracted pneumonia in November 1924. He was transferred then to the government hospital near the Kremlin.