Patent ID: 8497282

Claim:
A process for preparing (+)-1,4-dihydro-7-[(3S,4S)-3-methoxy-4-(methylamino)-1-pyrrolidinyl]-4-oxo-1-(2-thiazolyl)-1,8-naphthyridine-3-carboxylic acid comprising: i) epoxide opening Compound 3 with methylamine to obtain Compound 4, ii) resolving Compound 4 with a chiral acid selected from L-(−)-malic acid and L-(−)-pyroglutamic acid to provide Compound 5A or 5B iii) protecting the secondary amine of Compound 5A or 5B with tert-butoxycarbonyl protecting group to provide compound 6 iv) methylating the free hydroxyl group of Compound 6 with a methylating agent, v) deprotecting the amino groups with p-toluene sulfonic acid monohydrate to obtain Compound 8 vi) reacting Compound 8 with Compound 10 to obtain (+)-1,4-dihydro-7-[(3S,4S)-3-methoxy-4-(methylamino)-1-pyrrolidinyl]-4-oxo-1-(2-thiazolyl)-1,8-naphthyridine-3-carboxylic acid.