Improved large-scale synthesis of phenylisoserine and the taxol C-13 side chain

Pharmaceuticals

“…[329] An appealing alternative to the substitution with azide is provided by the Ritter reaction with benzonitrile, from which the oxazolines can be isolated as well. [324,330] It is interesting that the Ritter reaction produces a high (18:1) diastereomeric ratio. It may be assumed that the configuration of the benzyl cation is stabilised by the neighbouring hydroxy-group in the α-position.…”

Determination of enantiomeric excess for 2,3‐dihydroxy‐3‐phenylpropionate compounds by capillary electrophoresis using hydroxypropyl‐β‐cyclodextrin as chiral selector

“…Among them, the sharpless asymmetric dihydroxylation (AD) is the most promising means for efficient synthesis of a diverse range of chiral 1,2-dihydroxyl compounds in one step from the corresponding olefins. [4][5][6][7][8] For this reason, an increasing number of new chiral catalysts have been developed to enhance the enantioselectivity of AD reaction from the corresponding cinnamate for the desired (2R,3S)-(À)-2,3-dihydroxy-3-phenylpropionate enantiomer. As a result, there is an urgent need for stereoselective analytical techniques to determine the enantiomeric excess (ee) of (2R,3S)-(À)-2,3-dihydroxy-3-phenylpropionate products.…”

Yew (Taxus x media Rehd.) cell suspension cultures as a source of taxanes

“…They in clude se lection of proper inoculum, op ti mi za tion of cul ture con di tions and me dium, stim u la tion of taxane produc tion by ad di tion of paclitaxel pre cur sors (Fett --Netto et al 1994,Voronkov et al 2002 …”

“…Al though sev eral in vi tro approaches to taxane syn the sis such as hairy root cultures (Furmanowa et al 2000) or re con struct ing paclitaxel biosynthesis in a mi cro bial host with recom bi nant tech nol o gies (Jennewein et al 2005, Steele et al 2005 have been ap plied, cell sus pension cul tures de rived from dif fer ent Taxus spe cies are still an im por tant al ter na tive source of paclitaxel and other taxanes which could be con verted chem i cally to paclitaxel (Sohn et al 1998). Dif fer ent ap proaches have been used to pro duce sta ble, high yield cell cul tures. They in clude se lection of proper inoculum, op ti mi za tion of cul ture con di tions and me dium, stim u la tion of taxane produc tion by ad di tion of paclitaxel pre cur sors (Fett --Netto et al 1994,Voronkov et al 2002, Luo et al 2004, ad di tion of var i ous elicitors (Wu et al 2001, Bonfill et al 2003,Wang et al 2004, and even mitotic synchronisation of cell cul ture (Long-Jiang et al 2002). The most widely used elicitors are jasmonates, par tic u larly methyl jasmonate (MeJA).…”