With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.109-07-9,2-Methylpiperazine,as a common compound, the synthetic route is as follows.
Into a reactor with a working volume of 1000 mL equipped with a thermometer, a reflux condenser and a mechanical stirrer, DMSO (480 mL), l-cyclopropyl-6,7-difluoro-l,4-dihydro-8-methoxy-4-oxo-3-quinoline carboxylic acid (138.0 g; 0.4675 mole) and 2-methylpiperazine (94.0 g; 0.9387 mole) were put at 25C (20C-30C). The reaction mixture was stirred for 30 minutes at 25C (20C-30C). Then it was heated in 50 minutes (45-60 minutes) to the temperature of 73C. The reaction mixture was stirred at this temperature for 12 hours. After 12 hours at 73C, the reaction mixture was cooled to 25C in 45 minutes (40-50 minutes). The pH of the suspension was measured and adjusted to the pH value of 10.2 with a 15% HC1 solution (27.5 mL of 15% HC1) and the suspension was stirred for 24 hours. The pHof the suspension was periodically checked and adjusted to the desired value of 10.2 if necessary. When adjusting the pH vapours were formed, which were sucked off by underpressure and led through a trap with a solution of calcium hydroxide, which irreversibly bound fluoride ions. The product was then filtered over a filter MN 640 (black ribbon) and washed with methanol (165 mL). The product was thoroughly sucked off and the humidity was determined. Estimated yield of the dry gatifloxacin base: 52.0-54.7%., 109-07-9
As the paragraph descriping shows that 109-07-9 is playing an increasingly important role.
Reference：
Patent; KRKA, TOVARNA ZDRAVIL, D.D., NOVO MESTO; WO2006/4561; (2006); A1;,
Piperazine – Wikipedia
Piperazines – an overview | ScienceDirect Topics