3-Fluoro-4-morpholinoaniline

3-Fluoro-4-morpholinoaniline (3-fluoro-4-morpholin-4-ylaniline, also named 4-(4-amino-2-fluorophenyl)morpholine) is an aniline with a fluorine atom at C-3 and a morpholin-4-yl group at C-4. This 3-fluoro-4-(morpholin-4-yl)phenyl group is the N-aryl group of the oxazolidinone linezolid.

Oxazolidinones from aryl carbamates and glycidyl epoxides. A widely adopted strategy, in academic research and in industrial manufacture, builds the oxazolidinone ring by condensing an aryl carbamate with an enantiopure glycidyl-derived epoxide, such as epichlorohydrin, a glycidyl ester or a glycidylamine derivative, in the presence of a strong base. The base first deprotonates the aryl carbamate, and the ring closure has been reported to depend on bases with lithium as the counterion. The most direct version of this route to linezolid and its derivatives uses an epoxide that already carries the aminomethyl side chain, such as N-glycidylacetamide or related carbamates, imides and imines.

A three-component Mannich route. One study reported a short route to new oxazolidinone analogues. A three-component Mannich reaction of 3-fluoro-4-morpholinoaniline, aqueous formaldehyde and α-hydroxyacetone, mediated by L-proline under microwave heating, gives 4-(3-fluoro-4-morpholinophenylamino)-3-hydroxybutan-2-one; cyclisation with N,N′-carbonyldiimidazole then forms the oxazolidinone core. This route gives the oxazolidinone as a racemate, and the enantiomers were separated by chiral chromatography in that study.

Sulfonamides and carbamates. Its primary amino group reacts with aryl sulfonyl chlorides to give sulfonamides, and with chloroformates to give carbamates.

Schiff bases. Condensation with aldehydes gives Schiff bases (imines); linezolid-like Schiff bases have been made this way, including imines of 2-chloroquinoline-3-carbaldehydes.