The benzylester (3) and p-nitrobenzylester (PNB ester)(4) of the antibiotic PS-5 and the bis-protected PS-6 (5) were stereoselectively synthesised by application of the new carbon–carbon bond formation reaction at the C-4-position of 4-acetoxy-3-ethyl- or 4-acetoxy-3-ethyl- or 4-acetoxy-3-isopropyl-azetidin-2-ones [(10) or (11)].
(7), which has been stereoselectively synthesised via the 4-methoxycarbonylisoxazoline (4), was converted into (±)-epithienamycins A (2) and B (3)[(±)-olivanicacidsMM22380 and MM22382], (±)-deacetylepithienamycin A (20), and the 2-phenylthio-substituted compound (19). This totalsynthesis confirms the relative stereochemistry of the natural antibiotics.
已立体选择合成的(±)-(3 R *,4 R *)-4-(2,2-二甲氧基乙基)-3 [(1 S *)-1-羟乙基]氮杂环丁烷-2-酮(7)通过4-甲氧基羰基异恶唑啉(4)转化为(±)-上皮霉素A(2)和B(3)[(±)-寡酸MM22380和MM22382],(±)-脱乙酰基表艾霉素A(20)和2-苯硫基取代的化合物(19)。该总合成证实了天然抗生素的相对立体化学。
Studies on novel carbacephem analogs: synthesis of 7-methoxy-homo-PS-5 and a 7-methoxy-8-epi-homothienamycin intermediate
作者:S. R. Shakya、T. Durst
DOI:10.1139/v92-269
日期:1992.8.1
The synthesis of two carbacephems bearing a 7-methoxy group and either an additional ethyl (PS-5) or hydroxyethyl (thienamycin) side chain has been completed. Rhodium carbenoid insertion methodology was used to generate the bicyclic ring systems.
The present invention relates to novel 4-substituted-2-oxoazetidine compounds and to processes for preparing the same. These compounds are useful intermediates for preparing antibiotics having the basic skeleton of Thienamycin.
Routes of Synthesis of Carbapenems for Optimizing Both the Inactivation of <scp>l</scp>,<scp>d</scp>-Transpeptidase Ldt<sub>Mt1</sub> of <i>Mycobacterium tuberculosis</i> and the Stability toward Hydrolysis by β-Lactamase BlaC
five-membered rings of the carbapenem core. In particular, we show that the azide–alkyne Huisgen cycloaddition reaction catalyzed by copper(I) is fully compatible with the highly unstable β-lactam ring of carbapenems and that the triazole ring generated by this reaction is well tolerated for inactivation of the l,d-transpeptidase LdtMt1 target. Several of our new carbapenems are superior to meropenem