- Polycyclic derivatives and preparation thereof
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The invention discloses compounds shown as a formula (I) and a formula (II) and stereoisomers, pharmaceutically acceptable salts, solvates, hydrates, N-oxides and prodrugs thereof, pharmaceutical compositions and preparation methods of the compounds and t
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- Diversity-oriented approach to spirocycles via ring-closing metathesis
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We have demonstrated a simple and an efficient method for the synthesis of spirocycles starting with inexpensive and commercially available carbonyl compounds. Various spirocycles involving spiropropellane derivative have been assembled via ring-closing m
- Kotha, Sambasivarao,Ali, Rashid,Chinnam, Ajay Kumar
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p. 4492 - 4495
(2014/08/05)
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- An Improved Synthesis of Bicyclooctane-2,6-dione
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The Michael addition of dimethyl malonate (12) to tert-butyl acrylate (11), carried out without solvent, affords the triester 13a in 88percent yield on a kg scale.Selective partial hydrolysis of 13a produces the monoacid 13b almost quantitatively.The Kolbe electrolysis of 13b furnishes the tetraester 7c as a crystalline 1:1 mixture of diastereomers in 62-74percent yield.The Dieckmann condensation of 7c is induced by sodium hydride/tert-butyl alcohol in tetrahydrofuran and yield the enolized β-oxo ester 8c which, on acidic hydrolysis followed by decarboxylation, produces the title diketone 2 in 90percent yield, based on 7c.Thus, the useful diketone 2 is obtained in 46-55percent overall yield on a 100-g scale.Key Words: Malonate, dimethyl- / Acrylate, tert-butyl- / Bicyclooctane, derivatives of / Pentalene, perhydro-, derivatives of / Michael addition / Kolbe electrolysis / Dieckmann condensation
- Quast, Helmut,Janiak, Rolf
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p. 1305 - 1308
(2007/10/02)
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