US 11,667,654 B2
Process for the preparation of boronic acid esters
Maneesh Kumar Pandey, Haryana Gurgaon (IN); Raj Narayan Tiwari, Haryana Gurgaon (IN); Sonu Shukla, Haryana Gurgaon (IN); Sarbjot Singh Sokhi, Haryana Gurgaon (IN); Govind Singh, Haryana Gurgaon (IN); Saswata Lahiri, Haryana Gurgaon (IN); and Walter Cabri, Cassina de' Pecchi (IT)
Assigned to Fresenius Kabi Oncology Ltd., New Delhi (IN)
Appl. No. 16/484,346
Filed by FRESENIUS KABI ONCOLOGY LIMITED, New Delhi (IN)
PCT Filed Feb. 19, 2018, PCT No. PCT/IB2018/050999
§ 371(c)(1), (2) Date Aug. 7, 2019,
PCT Pub. No. WO2018/150386, PCT Pub. Date Aug. 23, 2018.
Claims priority of application No. 201711005668 (IN), filed on Feb. 17, 2017.
Prior Publication US 2020/0031850 A1, Jan. 30, 2020
Int. Cl. C07F 5/02 (2006.01)
CPC C07F 5/025 (2013.01) [C07B 2200/07 (2013.01)] 18 Claims
 
1. A process for preparing a compound of Formula IV,

OG Complex Work Unit Chemistry
the process comprising:
a) reacting a compound of Formula A,

OG Complex Work Unit Chemistry
wherein PG1 is tert-butyloxycarbonyl (Boc), pthaloyl, 9-fluorenylmethyloxycarbonyl (Fmoc), triphenylmethyl (Trityl), carboxybenzyl (Cbz), trifluoroacetyl (CF3CO), benzyl (Bn), benzylidene, methanesulfonyl (Mesyl), tosyl (Ts), or acyl;
with a compound of Formula B or its salt,

OG Complex Work Unit Chemistry
in the presence of a coupling agent and a base in a nitrile solvent to obtain a reaction mixture comprising a compound of Formula I,

OG Complex Work Unit Chemistry
b) adding water to the reaction mixture to precipitate the compound of Formula I as a solid, isolating the compound of Formula I as a solid which is substantially free of dimer impurities, and converting the compound of Formula Ito the compound of Formula IV.