METHOD OF PREPARATION OF STEREOSPECIFIC QUINONE DERIVATIVES
申请人:Mehta Dilip S.
公开号:US20150126763A1
公开(公告)日:2015-05-07
The description provides processes for the regio and stereospecific synthesis of polyprenylatedquinone derivatives, such as Vitamin K1, K2 and Ubiquinone, exploiting dithioacetals, especially 1,3-dithiane, mediated Umpolung chemistry which works along a new concept “Inhibiting resonance delocalization (IRD)” to overcome isomerization generated due to delocalization of allyliccarbanion on the π-electron cloud of an allylic systems by the conventional synthesis.
Hydroquinone derivatives useful in the production of vitamin E
申请人:Hoffmann-La Roche Inc.
公开号:US04689427A1
公开(公告)日:1987-08-25
The present invention is directed to novel hydroquinone derivatives which are useful as intermediates for the manufacture of (R,R,R)-.alpha.-tocopherol (natural vitamin E) as well as of racemic .alpha.-tocopherol. The invention is also directed to a process for the preparation of the hydroquinone derivatives of the invention.
The complete synthesis of D-α-tocopherol was achieved using our developed-Ullmann C-O coupling reaction as a key reaction. The synthesis of the core structure of D-α-tocopherol, which is a chiral chromane, has never been reported using intramolecular Ullmann C-O coupling reactions owing to the low reactivity of electron-rich iodoarenes with tertiary alcohols. Because the developed intramolecular C-O
SARs of vitamins: (2R,4′R,8′R)‐nor‐α‐Tocopherol has been prepared from (all‐R)‐hexahydrofarnesol in high (94 %) diasteromeric excess, and (2RS,4′R,8′R)‐nor‐α‐tocopherol has beeen prepared from phytol. nor‐α‐Tocopherol displays excellent antiinflammatory properties in vitro.