The present invention relates to a compound of the formula ##STR1## wherein X.sup.1, R.sup.1, R.sup.2, OP, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and R.sup.0 are as described herein, and their pharmaceutically acceptable salts thereof carrying an acidic and/or basic substituent. The compound of formula I as well as their pharmaceutically acceptable salts inhibit DNA gyrase activity in bacteria and possess antibiotic, especially antibacterial activity against microorganisms and can be used in the control or prevention of infectious diseases.
Chemical versus enzymatic acetylation of α-bromo-ω-hydroxyaldehydes: decyclization of hemiacetals by lipase
作者:Ly Villo、Andrus Metsala、Omar Parve、Tõnis Pehk
DOI:10.1016/s0040-4039(02)00502-6
日期:2002.4
Lipase-catalyzed decyclization of hemiacetals of α-bromo-ω-hydroxyaldehydes followed by trapping upon acetylation was observed. Quantum chemical investigations were performed to explain the energetic background of the reactions. The stereocontrolled synthesis of enantiopure trans-(2S,3S)-2-methoxy-tetrahydropyran-3-ol was elaborated.
deoxy sugar esters of different carboxylic acids has been achieved. The objective of the work was to extend the strategy to the synthesis of furanose deoxy sugar derivatives and additionally, to N-Boc-protected amino acid esters. With all used carboxylic acids (deoxycholic acid, α-methoxyphenylacetic acid, N-Boc-l-phenylalanine and N-Boc-l-tyrosine) the lipase-catalyzedstereoselective acetylation
Halogen Atom Participation in Guiding the Stereochemical Outcomes of Acetal Substitution Reactions
作者:Krystyna M. Demkiw、Wouter A. Remmerswaal、Thomas Hansen、Gijsbert A. van der Marel、Jeroen D. C. Codée、K. A. Woerpel
DOI:10.1002/anie.202209401
日期:2022.10.17
Nucleophilic additions to α-haloacetals proceed via an oxocarbenium ion intermediate where the carbon-halogen bond can either adopt a pseudo-axial or a pseudo-equatorial position. trans-Selectivity is typically observed when a halogen atom is positioned at C-2 of an acetal because hyperconjugative interactions involving the pseudo-axial carbon-halogen bond stabilize the oxocarbenium ion intermediate