Enzymatic Resolution of α-acetoxysulfides: A new approach to the synthesis of homochiral S,O-Acetals
摘要:
A novel enzymatic resolution of alpha-acetoxysulfides using Pseudomonas fluorescens lipase is reported. Selectivity is highly dependent on the substrate and solvent, with enantiomeric excesses of >95% in some cases. We believe these are the first examples of enzymatic resolutions of an S,O-acetal.
Organobase-catalyzed [1,2]-Brook rearrangement of silyl glyoxylates
作者:Man-Yi Han、Fei-Yan Yang、Di Zhou、Zhigang Xu
DOI:10.1039/c7ob00005g
日期:——
A highly efficient [1,2]-Brook rearrangement of silyl glyoxylates has been developed using DBU as the organobase-catalyst. This [1,2]-Brook rearrangement is applicable to a number of thiols and secondary phosphine oxides containing acidic protons. These nucleophiles afford the corresponding Brook products in high yields. Using this methodology, a formal synthesis of anti-HIV drug compound lamivudine
conformation and face selectivity was to be controlled through non-bonded steric interactions. Chirality was introduced from chiral pool materials (camphor, amino acids, lactic acid, limonene, carvone, glyceraldehyde), through enzyme mediated reduction/hydrolysis and through the use of chiral reagents (hydroboration). The sulfide catalysts were tested in the reaction between benzaldehyde tosylhydrazone salt
2-Substituted-4-substituted-1,3-dioxolanes and use thereof
申请人:Biochem Pharma Inc.
公开号:US06350753B1
公开(公告)日:2002-02-26
Nucleoside analogues containing a 1,3-dioxolane structure are suitable antiviral agents, particulary for the treatment of the HIV infections in mammals, especially humans. Examples of the nucleoside analogues include:
cis-2-acetoxymethyl-4-(thymin-1′-yl)-1,3,-dioxolane,
cis-2-hydroxymethyl-4-(thymin-1′-yl)-1,3-dioxolane,
cis-2-benzoyloxymethyl-4-(cytosin-1′-yl)-1,3-dioxolane, and
cis-2-hydroxymethyl-4-(cytosin-1′-yl)-1,3-dioxolane.
These compounds can be in the form of their racemates or their separate enantiomers.
Direct oxidative coupling of thiols and benzylic ethers via C(sp<sup>3</sup>)–H activation and C–O cleavage to lead thioesters
作者:J. Feng、M.-F. Lv、G.-P. Lu、C. Cai
DOI:10.1039/c4ob02250e
日期:——
An unprecedented C–S formation method via direct oxidative C(sp3)–H bond functionalization and C–O cleavage of benzylicethers was developed. Various thioesters including thioester structure containing drug intermediates could be achieved by this convenient, metal and base free method in satisfactory yields.
Synthesen in der Biotinreihe IV. Herstellung substituierter Thiophane
作者:C. A. Grob、H. Von Sprecher
DOI:10.1002/hlca.19520350331
日期:1952.5.2
Es wird eine Methode zum Aufbau von 2-substituierten 3,4-Diaminothiophanen mit Hilfe neuartiger Umsetzungen aliphatischer Nitroverbindungen beschrieben. Insbesondere wurde das bereits bekannte 2-Methyl-3,4-(2′ -oxo-tetrahydro-imidazol)-thiophan (IXa) nach dieser Methode hergestellt.