Process for preparing 1,2,4-Thiadiazole Derivatives
申请人:KATAYAMA SEIYAKUSYO CO. Ltd.
公开号:EP0536900A2
公开(公告)日:1993-04-14
Reaction of a 2-aminoisoxazole (A, where X is H or OR1) with a thiocyanate and an acyl halide (or their reaction product) and rearrangement of the product gives a 1,2,4-thiadiazole compound (B or C):
The compound B (X=H) can be oxidised and esterified to obtain C (X=OR1). The 3-substituent of compound C (-CH2.CO2R1) may be converted into
The thiadiazole compounds may be used to prepare acylating agents for preparation of therapeutically useful 7-acylaminocephalosporins.
将 2-氨基异噁唑(A,其中 X 为 H 或 OR1)与硫氰酸盐和酰基卤化物(或其反应产物)反应,并对产物进行重排,可得到 1,2,4-噻二唑化合物(B 或 C):
化合物 B(X=H)经氧化和酯化可得到 C(X=OR1)。化合物 C 的 3-取代基(-CH2.CO2R1)可转化为-CH2.CO2R2。
噻二唑化合物可用于制备酰化剂,以制备对治疗有用的 7-酰氨基头孢菌素。
A practical preparation of (Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(methoxyimino)acetic acid
A Z-isomer of 2-(5-amino- 1,2,4-thiadiazol-3-yl)-2-(methoxyimino)acetic acid, which is the common acyl moiety of clinically useful cephalosporins, has been prepared from the aminoisoxazols through the thiadiazol-acetate in two pathways.
Relationships between structure, antibacterial activity, serum stability, pharmacokinetics and efficacy in 3-(heteroarylthio)cephems. Discovery of RWJ-333441 (MC-04,546)
SAR studies in a series of related 3-(heteroarylthio)cephems determined that a relatively high chemical reactivity of the beta-lactam ring, modulated by electronic effects of substituents at C-3 and C-7, is necessary to achieve high in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA). Such high reactivity results in lowered hydrolytic stability and concomitantly increases susceptibility to beta-lactam ring opening mediated by serum enzymes. Therefore, optimization of anti-MRSA activity versus stability toward serum-mediated degradation required a fine balance of substituent effects. Serum stability studies (measured as percentage of parent drug degraded after 60 min incubation) revealed up to 80-fold difference in degradation rate in a series of closely related (3-heteroarylthio)cephems. Of the compounds evaluated, RWJ-333441 (MC-04,546) possessed the best balance of serum stability (6% degradation after 60 min incubation) and in vitro activity versus MRSA (S. aureus COL MIC-I mug/mL). Accordingly, RWJ-333441 displayed excellent in vivo efficacy versus methicillin-susceptible Staphylococcus aureus (MSSA, ED50=0.39 mg/kg in mouse sepsis model with S. aureus Smith) and good pharmacokinetic properties in the rat (Cl-total=0.39 L/h/kg). (C) 2002 Elsevier Science Ltd. All rights reserved.