The enantioselective synthesis of (R)- and (S)-3-amino-3,4-dihydro-1H-[1,8]naphthyridin-2-one

A number of approaches to the enantioselective synthesis of (R)- and (S)-3-amino-3,4-dihydro-1H-[1,8]naphthyridin-2-one were studied. A novel one-pot asymmetric reduction/lactamization provided the desired products in high yield and enantiomeric excess.

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(R)-tert-Butyl 2-oxo-1,2,3,4-tetrahydro-1,8-naphthyridin-3-ylcarbamateC13H17N3O3[α]D = +27.0 (c 1.50 mg/mL, CH3OH)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)

(R)-3-Amino-3,4-dihydro-1H-[1,8]naphthyridin-2-one 2HClC8H9N3O-2HCl[α]D = +50.1 (c 1.25 mg/mL, CH3OH)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)

(R)-tert-Butyl 2-(diphenylmethyleneamino)-3-(2-nitropyridin-3-yl)propanoateC25H25N3O4[α]D = +182.6 (c 10.3 mg/mL, CH3OH)Source of chirality: asymmetric synthesisAbsolute configuration: (2R)

(R)-tert-Butyl 3-(2-chloropyridin-3-yl)-2-(diphenylmethyleneamino)propanoateC25H25ClN2O2[α]D = +240.9 (c 12.7 mg/mL, CH3OH)Source of chirality: asymmetric synthesisAbsolute configuration: (2R)