Stannous chloride dihydrate → 1,3-Naphthalenediamine

Participants

Reaction Steps

A suspension of (3) (1.0 g, 2.9 mmol) and SnCl2.2H2O (9.8 g, 436 mmol) in EtOAc (100 mL) was heated at reflux for 30 min. The white suspension was poured onto ice (ca. 100 g), and sat. aq. NaHCO3 was added until the aqueous layer was basic as shown by litmus paper inspection. The mixture was extracted with ethyl acetate, the organic layer was washed with water, dried and the solvent was removed under reduced pressure to give crude 1,3-naphthalenediamine. This material was dissolved in THF (30 mL) and treated with BOC2O (3.0 g). The mixture was heated under reflux for 5 hrs. The solvent was removed and the residue was purified by column chromatography on silica gel. Elution with CH2Cl2 gave naphthalene-1,3-(bis-tertbutoxycarbamate) (4) (0.916 g, 88%) as a brown solid: mp (petroleum ether) 129–131° C.; 1H NMR (CDCl3) δ 7.94 (s, 1H), 7.78 (s, 1H), 7.74 (m, 2H), 7.41 (m, 2H), 6.94 (s, 1H), 6.69 (s, 1H), 1.55 (s, 9H), 1.54 (s, 9H); 13C NMR δ 153.11, 152.75, 135.75, 134.75, 133.69, 128.47, 126.46, 124.36, 122.28, 119.67, 110.57, 110.47, 80.88, 80.57, 28.33. Anal (C20H26N2O4) C, H, N.

Provenance & Evidence