Phosgene → HCID 22954557, compound

Participants

Reaction Steps

A solution of (3S)-1-benzyl 3-t-butyl hexahydropyridazine-1,3-dicarboxylate (Hassall et al. J. Chem. Soc. Perkin 1, pp. 1451-1454 (1979)) (925.3 mg, 2.89 mmol) and diisopropylethylamine (0.70 ml, 4.0 mmol) in a 1.93M toluene solution of phosgene (17.96 ml, 34.7 mmol) was stirred at room temperature for 45 min, then concentrated to leave a yellow solid. To this solid was added toluene (18 ml), hydrazide (259) (861.6 mg, 2.89 mmol) and diisopropylethylamine (0.70 ml, 4.0 mmol). The mixture was stirred at room temperature for 2.75 h, then concentrated. The resulting residue was taken up in EtOAc, washed twice with 1M HCl, brine, then dried (MgSO4), filtered and concentrated to afford 2.15 g of crude material. Flash chromatography (40% EtOAc in hexane) afforded 1.65 g (89%) of the title compound as a white foam: mp 40° C.; [α]D24 −55.78° (c 0.40, CH2Cl2); IR (KBr) 3436, 2930, 1733, 1689, 1455, 1412′ 1367, 1258, 1156, 697; 1H NMR (CDCl3) δ 8.54-8.23 (0.5H, m), 7.97-7.09 (15.5H), 5.16-4.80 (4H, m), 4.66-4.32 (1H, m), 4.24-3.55 (3.3H, m), 3.50-3.26 (0.4H, m), 3.19-2.49 (2.3H, m), 2.11-1.43 (6H, m), 1.32-1.05 (7H, m); Anal. Calcd for C35H40N4O8.0.5H2O: C, 64.31; H, 6.32; N, 8.57. Found: C, 64.18; H, 6.27; N, 8.56. MS (ES +) 662 (M+Na, 84%), 645 (M++1, 100), 384 (77).

Provenance & Evidence