反应详情

A solution of 458 mg. (1 mmol.) of t-butyl 7-phthalimido-3-acetoxymethyl-3-cephem-4-carboxylate in 10 ml. of THF was cooled in an ice water bath, and 1.1 ml. of 1N NaOH were then added. After stirring for 5 min., 10 ml. of water and 30 ml. of ethyl acetate were added. The ethyl acetate layer was separated, and 70 mg. of starting material were recovered therefrom. The aqueous layer was acidified to pH 4.0, and the acidified layer was extracted with ethyl acetate. After workup, 330 mg. (83%) of the desired phthalamic acid were obtained [α] + 26.37 (MeCN); λEtOH 260 mμ (ε 8800); ir (CHCl3) 1785, 1730 and 1685 cm-1 ; nmr (CDCl3) δ 1.55 (s, 9, t-Bu), 2.05 (s, 3, Ac), 3.3 and 3.6 (ABq, 2, J = 17 Hz), 4.72 and 5.2 (ABq, 2, J = 14 Hz), 4.98 (d, 1, J = 4.5 Hz), 5.9 (dd, 1, J = 4.5 and 9 Hz), and 7.5-8 (m, 4, ArH).

1. customThe ethyl acetate layer was separated
2. customof starting material were recovered
3. extractionthe acidified layer was extracted with ethyl acetate