Cephradine yields an unique alkaline degradation product, which has been identified by proton magnetic resonance, IT-NMR, and mass spectrometry as 2-[6-(1,4-cyclohexadine-lyl) -2.5dioxo -3piperazinyl] -5,6-dihydro -5methyl -2H-1,3thiazine-4carboxylic acid, sodium salt. Keyphrases 0 Cephradine-structure determination of alkaline degradation product as 2-[6-(1,4-cyclohexadine-l-yl)-2,5-dioxo-3piperazinyl]-5,6-dihydro-5-met hyl-2H-l.3-thiazine-4-carboxylic acid, sodium salt 0 2-[6-( 1 ,J-Cyclohexadine-I -yl)-2,5-dioxo-3-piperazinyl]-5,6-dihydro-5-methyl-2H-1,3-thiazine-4-carboxylic acid, sodium salt-cephradine alkaline degradation product, structure determination 0 Cephem derivatives-structure determination of cephradine alkaline degradation product The alkaline hydrolysis of penicillins and, more recently, of ampicillin (a-arninobenzylpenicillin) was investigated extensively (1). Similar studies into the aminolysis products of ccphalosporins were also reported ( 2 ) . The structure of the alkaline degradation product of cephradine, a new semisynthetic cephem derived from D-2-( 1,4-~yclohexadienyl)glycine and desacetoxy-7-arninocephalosporanic acid ( 3 ) , is reported here. EXPERIMENTAL] Materials-Cephradine*, 7-[~-2-amino-2-( I ,4-cyclohexadien-1yl)acetamido]-3-methyl-8-oxo-5-thia-1 -azabicyclo[4.2.0]oct-2ene-2carboxylic acid hydrate. was prepared by the procedure of Dolfini e! a/.
(3). The sample was characterized by NMR and by mass spectrometry as its trimethylsilyl derivative (Fig. 1). Anhydrous sodium carbonate (reagent grade), sodium hydroxide, or 20% sodium deuteroxide in deuterium oxide was used in the degradation studies. Either N,O-bis(trimethylsilyl)acetamide3 or trimethyl-chlorosilane3 was employed as the silylating agent.
Preparation of Degradation Product-Cephradine (3.0 g.) and sodium carbonate (9.0 g.) were mixed thoroughly. Then 1.6 g. of the mixture was transferred to a vial, 5 ml. of water was added, and the vial was capped and agitated. The vial was stored at 5" for 1 week. The white precipitate that formed was collected on a sinteredglass funnel. The filter cake was washed with five 2-ml. portions of cold water and then with three I-ml. portions of 95% ethanol and was dried by suction. The crystals were further dried in a vacuum oven at 40" for 3 hr. The mass spectrum of the trimethylsilyl derivative of the isolated products shows a molecular ion of m/e 565.2297, corresponding to the addition of three trimethylsilyl groups, Cta-H43N30CSSi3 (calc. 565.2280). PMR (dimethyl sulfoxide-& and tetramethylsilane): 6 1.06 (3H,,d, J = 7 Hz.), 2.95 (2H, m), 5.05 ( l H , m , J = 3 Hz.), 2.6 (5H, m), 4.19 (IH, t, J = 3 Hz.) [which, on deuterium exchange, becomes a doublet (J = 3 Hz.)],4.93 ( l H , WI j 2 = 3 Hz.) (which has a WI = 2 Hz. after deuterium exchange), 'Proton magnetic resonance (PIMR) spectra were obtained on a Varian Associates XL-100 spectrometer employing the deuterium fieldfrequcncy lock system. The 13C-magnetic resonance ( I T -N M R ) spectrum was taken on a JEOL PS-100 cquipped with a Fourier transform pulser and a Nicolet computer. At 25.1 MHz.. the eKective sweep range was SO00 Hz. (300 p.p.m.). Lowand high-resolution mass spectra were taken on a n AEI MS-902 mass spectrometer. Data were acquired cia a frequency-modulated analog magnetic tape. which was subsequently orocesscd on a Dinital Eauioment Coro. PDP-11 cornouter. emDlovinn -. . ~ .