- Synthesis of prostaglandins III: Efficient and practical synthesis of antisecretory prostaglandin enprostil
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An efficient and practical 8-step synthesis of enprostil (1) starting from the lactone 2 has been developed. The propargylic acetate 5 was prepared from the lactol 3 by the reaction with ethynylmagnesium bromide followed by acetylation. Propargylic acetate 5 was converted into enprostil (1) via the introduction of an allene moity by reaction with a Grignard reagent in the presence of a CuI · P(OEt)3 complex.
- Lee,Nam,Jung,Park
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p. 792 - 794
(2007/10/02)
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- Synthesis of a Key Intermediate for Preparation of 4,5-Didehydro Prostaglandins containing an Allenyl Side-chain Group via Two-component Coupling Process. Synthesis of Enprostil
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Enone 8, a key intermediate in the preparation of 4,5-didehydro prostaglandins via a two component coupling process, is prepared efficiently from readily available enone 6; the synthesis of enprostil, an antiulcer agent developed by Syntex, using enone 8 is also described.
- Ono, Naoya,Kawanaka, Yasufumi,Yoshida, Yukio,Sato, Fumie
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p. 1251 - 1252
(2007/10/02)
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- Triply Convergent Synthesis of 15-(Phenoxymethyl) and 4,5-Allenyl Prostaglandins. Preparation of an Individual Isomer of Enprostil
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A triply convergent synthesis of the PGE2 derivatives 1, 3, 4, and 5, containing either the 15-(phenoxymethyl) or the 15-amyl ω side chain and the 5,6-didehydro or the 4,5-allenyl α side chain, is described.This two-pot method employs organocopper reagents of the type Li2RωCuCNMe to selectively introduce the ω side chain to enantiopure enone 6 followed by in situ trapping of the so-formed enolates as silyl enol ethers 22a and 22b.The key step is the alkylation of regiochemically defined lithium enolates, generated from the corresponding silyl enol ethers 22a and 22b, with the unsaturated α side chain triflates 8b and 9c.The method was found to be general for propargylic and allenic α side chains but unsuccessful for the cis allylic and saturated α side chains found in PGE2 and PGE1, respectively.
- Gooding, Owen W.,Beard, Colin C.,Cooper, Gary F.,Jackson, David Y.
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p. 3681 - 3686
(2007/10/02)
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- (dl)-16-Phenoxy- and 16-substituted phenoxy-9-keto prostatrienoic acid derivatives and processes for the production thereof
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Novel 16-phenoxy and 16-(o, m or p)-substituted phenoxy derivatives of (dl)-9-keto-11α,15α-dihydroxy-17,18,19,20-tetranorprosta-4,5,13-trans-trienoic acid, the pharmaceutically acceptable, non-toxic lower alkyl esters and salts thereof and processes for the production of such compounds. These compounds possess prostaglandin-like activities and thus are useful in the treatment of mammals where prostaglandins are indicated. They are particularly useful as inhibitors of gastric acid secretion; and as agents for the control of asthmatic attack, because of their bronchodilating activity.
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