Sodium Bicarbonate → 1-Cyclopentyl-2-(2-methyl-4-nitrophenylimino)-3-thia-1-azaspiro[4.4]nonane

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Reaction Steps

To 1-cyclopentyl-2-(2-methyl-4-nitrophenylimino)-3-thia-1-azaspiro[4.4]nonane HCl salt (Method C6b; 52.4 g, 0.132 mol) dissolved in a mixture of water (300 mL) and EtOAc (500 mL) wag added NaHCO3 (15 g, 0.178 mol, 1.3 equiv.). The mixture was stirred for 1 h and the resulting organic layer was dried (MgSO4) concentrated under reduced pressure. The resulting light yellow solid was treated with EtOH (100 mL), and concentrated under reduced pressure twice to give 1-cyclopentyl-2-(2-methyl-4-nitrophenylimino)-3-thia-1-azaspiro[4.4]nonane (46 g, 97%): mp 111-112° C.; 1H NMR (CDCl3) δ1.49-1.53 (m, 2H), 1.63-1.80 (m, 8H), 1.81-1.91 (m, 4H), 2.21 (s, 3H), 3.02 (s, 2H), 3.60-3.70 (m, 1H), 6.87 (d J=8.5 Hz, 1H), 8.02 (m, 2H), CI-MS m/z 360 ((M+H)+).

Provenance & Evidence