38418-34-7Relevant academic research and scientific papers
A new efficient synthesis of GR24 and dimethyl A-ring analogues, germinating agents for seeds of the parasitic weeds Striga and Orobanche spp.
Malik, Heetika,Rutjes, Floris P.J.T.,Zwanenburg, Binne
experimental part, p. 7198 - 7203 (2010/10/02)
An efficient and high yielding preparation for the synthetic germination stimulant GR24 (5) and its A-ring dimethyl-substituted analogues 30-32 has been described. The first step involves a Stobbe condensation of benzaldehydes 9-11 with dimethyl succinate. Subsequent transposition of the ester and reduction of the double bond provides the building blocks 15-17 for an intramolecular Friedel-Crafts acylation. ABC-lactones 22-25 are prepared from γ-keto esters 18-21 by saponification, subsequent reduction with sodium borohydride followed by acid-catalyzed lactonization. Coupling of the lactones with the D-ring is accomplished by formylation and subsequent treatment with bromobutenolide 8 to give GR24 and its dimethyl analogues. Bioassays with Striga hermonthica seeds reveal that the dimethyl analogues are slightly less active than GR24 itself.
Synthesis of versatile building blocks through asymmetric hydrogenation of functionalized itaconic acid mono-esters
Hekking, Koen F. W.,Lefort, Laurent,De Vries, Andre H. M.,Van Delft, Floris L.,Schoemaker, Hans E.,De Vries, Johannes G.,Rutjes, Floris P. J. T.
experimental part, p. 85 - 94 (2009/04/07)
The rhodium-catalyzed asymmetric hydrogenation of several β-substituted itaconic acid monoesters, using a library of monodentate phosphoramidite and phosphite ligands is described. Two β-alkylsubstituted substrates were readily hydrogenated by the rhodium complex Rh(COD) 2BF4 in combination with (S)-PipPhos as a ligand resulting in ees of 99 %. In contrast, the corresponding more hindered β-arylsubstituted substrates did not exhibit acceptable enantioselectivities under these conditions. However, the use of a 48-membered ligand library led to the identification of several suitable ligands for these substrates, resulting in ees of 89-99%. The resulting optically active succinic acid derivatives are potentially useful building blocks for more elaborate compounds, because of the ability to differentiate between the carboxylic acid and the ester groups on either side of the molecule.
Catalytic asymmetric alkynylation and arylation of aldehydes by an H 8-binaphthyl-based amino alcohol ligand
Ruan, Jiwu,Lu, Gui,Xu, Lijing,Li, Yue-Ming,Chan, Albert S. C.
experimental part, p. 76 - 84 (2009/04/11)
A novel chiral H8-1,1'-binaphthyl-based amino alcohol ligand (1Ra,2S,3R)-2 has been synthesized and applied in the direct nucleophilic addition of organozincs (alkynylzinc and arylzinc prepared in situ) to aldehydes, yielding the corresponding optically active propargylic alcohols and diarylmethanols in high yields and good to excellent enantioselectivities. For the asymmetric arylation reaction, one catalyst (1Ra,2S,3R)-2 can afford both enantiomers of many pharmaceutically interesting diarylmethanols by a proper combination of various arylzinc reagents and aldehydes.
Ring opening of cyclic anhydrides: Synthesis of achiral half-esters using Lewis acids
Sabitha, Gowravaram,Srividya,Yadav
, p. 4015 - 4018 (2007/10/03)
A rapid and high yield preparation of half-esters from cyclic anhydrides using alcohols and Lewis acids is described.
HYDROXYCARBAMOYLALKYLACYLPIPECOLIC ACID COMPOUNDS
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, (2008/06/13)
New hydroxycarbamoylalkylacyl derivatives of pipecolic acid which have the general formula STR1 are useful as angiotensin converting enzyme inhibitors.
CARBOXYACYLPROLINE DERIVATIVES
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, (2008/06/13)
New carboxyalkylacylamino acids which are derivatives of proline, pipecolic acid and azetidine-2-carboxylic acid and have the general formula STR1 are useful as angiotensin converting enzyme inhibitors.
