反应详情

Phosphorus oxychloride (0.5 ml. 5.47 mmole) was added dropwise over 3 min. to a stirred suspension of 2,2,2-trichloroethyl 7β-formamido-3-methylthiomethylceph-3-em-4-carboxylate (1.05 g., 2.5 mmole) in dry methanol (10 ml.). During the addition the starting material went into solution and the temperature of the mixture reached a maximum of ca.45°. After 1 min. a white solid came out of solution and the mixture rapidly set solid. The mixture was diluted with ether (10 ml.), stirred briefly and the product collected, washed with ether (ca. 25 ml.) and dried to furnish the title hydrochloride as a feathery white solid (941 mg., 88%), m.p. 169° to 172° (dec.) [α]D + 5.25°, λmax. (MeOH) 272.5 nm. (ε 6,640), νmax. ca. 2600 (N+H3), 1775 (azetidin-2-one) and 1720 cm-1 (CO2CH2CCl3), τ 4.69 (1H,d, J 5 Hz; C7 -H), 4.88 and 5.01 (2H,AB-q, J 12 Hz; CH2CCl3), 4.90 (1H,d, J 5 Hz; C6 -H), 6.14 and 6.39 (2H,AB-q,J17 Hz C2 -CH2), 6.23 (2H,s; CH2SCH3) and 7.97 (3H,s; SCH3) (Found: C, 31.2; H, 3.3; Cl, 33.0; N, 6.6; S, 15.0. C11H 14 Cl4N2O3S2 (428.2) requires C, 30.85, H, 3.3; Cl, 33.1; N, 6.55; S, 15.0%). Electrophoresis showed a single spot, RX 1.56 (X=cephalexin) which migrated towards the cathode and which gave a mauve colour upon spraying with 0.5% (W/V) ninhydrin in ethanol.

1. additionDuring the addition the starting material
2. custom45°
3. customthe product collected
4. washwashed with ether (ca. 25 ml.)
5. customdried