Claims for Patent: 11,261,198

Summary for Patent: 11,261,198

Title:	Process for preparing substituted polycyclic pyridone derivative and crystal thereof
Abstract:	The present invention provides a process for preparing a compound of the formula (II):wherein R2 is unsubstituted alkyl,characterized by reacting a compound of the formula (I):wherein R1 is hydrogen or a protecting group other than unsubstituted alkyl,with a compound of the formula: R2—OH, wherein R2 is as defined above, in the presence of a sodium salt and/or a magnesium salt.
Inventor(s):	Setsuya SHIBAHARA, Kosuke Anan
Assignee:	Shionogi and Co Ltd
Application Number:	US16/310,897
Patent Claims:	1. A process for preparing a compound of the formula (IV): or a salt thereof, wherein R3, R4, R5 and R6 are each independently hydrogen or halogen, provided that one or two of R3, R4, R5 and R6 is halogen; the process comprising reacting a compound of the formula (II′): or a salt thereof, with a compound of the formula (III): or a salt thereof, wherein R3, R4, R5 and R6 are as defined above. 2. The process according to claim 1, wherein R3 is hydrogen, R4 is hydrogen, R5 is fluorine, and R6 is fluorine. 3. A process for preparing a compound of the formula (V) or formula (VI): or a salt thereof, which comprises preparing a compound of the formula (II): or a salt thereof, wherein R2 is unsubstituted alkyl; wherein the process of preparing the compound of the formula (II) comprises reacting a compound of the formula (I): wherein R1 is hydrogen or a protecting group other than unsubstituted alkyl, with a compound of the formula: R2—OH, wherein R2 is as defined above, in the presence of a sodium salt and/or a magnesium salt. 4. A compound of the formula (IV′): or a salt thereof. 5. A mesylate salt of the compound of formula (IV′) according to claim 4. 6. A crystal of the mesylate salt according to claim 5. 7. A crystal of a compound of the formula (V): or a crystal of a pharmaceutically acceptable salt thereof. 8. The crystal according to claim 6, comprising an X-ray powder diffraction pattern wherein the diffraction angles (2θ) of at least two peaks are selected from the group consisting of 7.1±0.2°, 9.3±0.2°, 12.6±0.2°, 14.1±0.2°, 17.7±0.2°, 18.7±0.2°, 19.2±0.2°, 22.2±0.2°, 25.4±0.2°, 27.7±0.2°, 28.5±0.2°, and 37.8±0.2°. 9. The crystal according to claim 6, comprising an X-ray powder diffraction pattern comprising peaks at the diffraction angles (2θ) of 7.1±0.2°, 9.3±0.2°, 12.6±0.2°, 14.1±0.2°, 17.7±0.2°, 18.7±0.2°, 19.2±0.2°, 22.2±0.2°, 25.4±0.2°, 27.7±0.2°, 28.5±0.2°, and 37.8±0.2°. 10. The crystal according to claim 6, having a melting point of 219° C.±2° C. in differential scanning calorimetry. 11. The crystal according to claim 7, comprising an X-ray powder diffraction pattern wherein the diffraction angles (2θ) of at least two peaks are selected from the group consisting of 9.6±0.2°, 10.9±0.2°, 17.8±0.2°, 21.5±0.2°, 22.1±0.2°, 23.5±0.2°, and 24.8±0.2°. 12. The crystal according to claim 7, comprising an X-ray powder diffraction pattern comprising peaks at the diffraction angles (2θ) of 9.6±0.2°, 10.9±0.2°, 17.8±0.2°, 21.5±0.2°, 22.1±0.2°, 23.5±0.2°, and 24.8±0.2°. 13. A process for preparing a compound of the formula (IV′): or a salt thereof, the process comprising reacting a compound of the formula (II′): or salt thereof, with a compound of the formula (III): or a salt thereof, wherein R3 is hydrogen, R4 is hydrogen, R5 is fluorine, and R6 is fluorine.