- Process for the preparation of 4,5-diamino shikimic acid derivatives
-
The present invention relates to a process for the preparation of a 4,5-diamino shikimic acid derivative of formula and pharmaceutically acceptable addition salts thereof wherein R1, R1′ are independent of each other H or alkyl, R2 is an alkyl and R3, R4 are independent of each other H or an alkanoyl, with the proviso that not both R3 and R4 are H. 4,5-diamino shikimic acid derivatives of formula I, especially the (3R,4R,5S)-5-amino-4-acetylamino-3-(1-ethyl-propoxy)-cyclohex-1-ene-carboxylic acid ethyl ester and its pharmaceutically acceptable additional salts are potent inhibitors of viral neuraminidase.
- -
-
Page/Page column 6-7
(2008/06/13)
-
- The synthetic development of the anti-influenza neuraminidase inhibitor oseltamivir phosphate (Tamiflu): A challenge for synthesis & process research
-
The evolution of the synthesis of oseltamivir phosphate (Tamiflu), used for the oral treatment and prevention of influenza virus infections (viral flu) is described. Oseltamivir phosphate is the ethyl ester prodrug of the corresponding acid, a potent and selective inhibitor of influenza neuraminidase. The discovery chemistry route and scalable routes used for kilo laboratory production as well as the technical access to oseltamivir phosphate from (-)-shikimic acid proceeding via a synthetically well-developed epoxide building block followed by azide transformations are reviewed. Synthesis and process research investigations towards azide-free conversions of the key epoxide building block to oseltamivir phosphate are discussed. The search for new routes to oseltamivir phosphate independent of shikimic acid including Diels-Alder approaches and transformations of aromatic rings employing a desymmetrization concept are presented in view of large-scale production requirements.
- Abrecht, Stefan,Harrington, Peter,Iding, Hans,Karpf, Martin,Trussardi, Rene,Wirz, Beat,Zutter, Ulrich
-
p. 621 - 629
(2007/10/03)
-
- New, azide-free transformation of epoxides into 1,2-diamino compounds: Synthesis of the anti-influenza neuraminidase inhibitor oseltamivir phosphate (Tamiflu)
-
A new, azide-free transformation of the key precursor epoxide 6 to the influenza neuraminidase inhibitor prodrug oseltamivir phosphate (1, Tamiflu) is described. This sequence represents a new and efficient transformation of an epoxide into a 1,2-diamino compound devoid of potentially toxic and hazardous azide reagents and intermediates and avoids reduction and hydrogenation conditions. Using catalytic MgBr2·OEt2 as a new, inexpensive Lewis acid, the introduction of the first amino function was accomplished by opening of the oxirane ring with allylamine followed by Pd/C-catalyzed deallylation to the amino alcohol 16. The introduction of the second amino group was then accomplished via an efficient reaction cascade involving a domino sequence preferably utilizing a transient imino protection. Selective acetylation of the resulting diamine 17 was achieved under acidic conditions providing the crystalline 4-acetamido-5-N-allylamino-derivative 18, which upon deallylation over Pd/C and phosphate salt formation afforded drug substance 1. The overall yield of this route from 6 of 35-38% exceeds the yield of the azide-based process (27-29%) and does not require any chromatographic purification.
- Karpf,Trussardi
-
p. 2044 - 2051
(2007/10/03)
-