Xuejun Liu

US Patent:

20210276942, Sep 9, 2021

Filed:

Feb 11, 2019

Appl. No.:

16/967627

Inventors:

- South San Francisco CA, US
Peter LEEMING - Monrovi CA, US
Emerich EISENREICH - Claremont CA, US
Xuejun Karl LIU - Arcadia CA, US

International Classification:

C07C 227/18
C07C 227/32
C07C 227/16
C07C 269/06
C07C 271/22
C07C 229/36
C07C 227/40

Abstract:

The invention relates to an overall enantio-specific synthesis of 4-chlorokynurenine compounds, in particular L-4-chlorokynurenine, with improved yields. Large-scale syntheses are disclosed. The invention also relates to novel intermediates in the synthesis of L-4-chlorokynurenine.

US Patent:

20180179156, Jun 28, 2018

Filed:

Jun 6, 2016

Appl. No.:

15/736662

Inventors:

- Canandaigua NY, US
Emerich Eisenreich - Claremont CA, US
Xuejun Karl Liu - Arcadia CA, US
Bingidimi Itute Mobele - Altamont NY, US
Satish Goud Puppali - Rancho Cucamonga CA, US

International Classification:

C07D 207/12
C07C 53/126
C07C 57/12
C07C 57/03

Abstract:

Novel glycopyrronium fatty acid salts have been developed. Bi-phasic reaction conditions enable the desired counterion exchange reactions between glycopyrronium bromide and fatty acid salts of alkali metals and alkaline earth metals in methods to form glycopyrronium fatty acid salts. In preferred embodiments, an excess of the free fatty acid in the reaction mixture stabilizes the glycopyrronium fatty acid salt and reduces the formation of the impurity, Acid A. In some preferred embodiments, between 0.2 and 1.2 molar equivalent of excess free fatty acid is added to the reaction mixture. In another embodiment, approximately 1.2 molar equivalent of excess free fatty acid is added to the reaction mixture.