Dracen Pharmaceuticals, Inc.

Tetra Discovery Partners, LLC

Jon Philip Lawson

Pavel Majer

Yiyang Shao

Jinxiao Chu

Robert Christian Wild

Jinchao Weng

Mark E Gurney

Stephan D Parent

Richard James Ely

Martin Hadzima

Lukáš Tenora

Ivan Šnajdr

The present disclosure provides methods of preparing a compound of Formula (I): wherein R, R, and Rare as defined as set forth in the application. In one embodiment, a compound of Formula (I) is prepared in >95% chemical purity and >95% enantiomeric excess.

Method of preparing a DON prodrug from L-glutamic acid

The present disclosure provides a method of preparing a compound of Formula I, wherein Ris C-Calkyl; Ris C1-C4 alkyl; and Ris selected from the group consisting of C-Calkyl, (aryl)alkyl, and (heteroaryl)alkyl in &#x3e;95% chemical purity and &#x3e;95% enantiomeric excess.

Method of preparing a DON prodrug from L-pyroglutamic acid

Provided herein are free base crystalline forms and crystalline salts of Compound 1.

Salts and polymorphs of a PDE4 inhibitor

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Wildwood, MO, United States of America

Jon Philip Lawson