| 1. |
- Almqvist, Fredrik, et al.
(författare)
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An Improved Procedure for the Synthesis of Bicyclo[2.2.2]octane- 2,6-dione
- 1993
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Ingår i: Synthetic Communications. - : Informa UK Limited. - 0039-7911 .- 1532-2432. ; 23:11, s. 1499-1505
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Tidskriftsartikel (refereegranskat)abstract
- Conjugate addition of Meldrum's acid to 2-cyclohexenone followed by direct cyclization in PPA/acetic acid constitutes a shorter, more reproducible and higher yielding route to bicyclo[2.2.2]octane-2,6-dione than previous methods. The crude dione could be used as substrate for the baker's yeast reduction to (IR, 4S, 6S)-bicyclo[2.2.2]octane-6-ol-2-one.
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| 2. |
- Almqvist, Fredrik, et al.
(författare)
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Neighboring Group Participation in a Regio- and Stereoselective Chlorination of a Bicyclo[2.2.2]octanone
- 1996
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 1520-6904 .- 0022-3263. ; 61:20, s. 6947-6951
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Tidskriftsartikel (refereegranskat)abstract
- The zinc chloride-mediated acetylation of the optically active silyl enol ether 2a gave the beta-diketone 3a (48%) together with the regio- and stereoselectively chlorinated compound 4 (27%). The yield of 4 increased to 70% by starting from the O-acetyl derivative 2c. The chlorination most likely occurs via neighboring group participation by the endo acetoxy group.
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| 3. |
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| 4. |
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| 5. |
- Almqvist, Fredrik, et al.
(författare)
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Spirobicyclo[2.2.2]octane derivatives: mimetics of baccatin III and paclitaxel (Taxol)
- 2004
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Ingår i: Organic and Biomolecular Chemistry. - 1477-0539. ; 2:21, s. 3085-3090
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Tidskriftsartikel (refereegranskat)abstract
- The formylated spirobyclic alcohol 8a was computer modeled to be a mimetic of paclitaxel. In this model, the formyl group was used as a truncated paclitaxel side chain in order to reduce the computational work. Compound 8c, carrying the paclitaxel side chain, was synthesized in six steps from optically active 1,3-diketone 12. Microtubule stabilization was not observed for 8c, indicating that the model needs to be adjusted.
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| 6. |
- Almqvist, Fredrik, et al.
(författare)
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Spirobicyclo[2.2.2]octane derivatives: mimetics of baccatin III and paclitaxel (Taxol)
- 2004
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Ingår i: ORGANIC & BIOMOLECULAR CHEMISTRY. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 2:21, s. 3085-90
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Tidskriftsartikel (refereegranskat)abstract
- The formylated spirobyclic alcohol 8a was computer modeled to be a mimetic of paclitaxel. In this model, the formyl group was used as a truncated paclitaxel side chain in order to reduce the computational work. Compound 8c, carrying the paclitaxel side chain, was synthesized in six steps from optically active 1,3-diketone 12. Microtubule stabilization was not observed for 8c, indicating that the model needs to be adjusted.
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| 7. |
- Almqvist, Fredrik, et al.
(författare)
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Synthesis of Optically Active endo, endo Bicyclo[2.2.2]octane-2,5- diol, Bicyclo[2.2.2]octan-2,5-dione and Related Compounds
- 1996
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 1520-6904 .- 0022-3263. ; 61:11, s. 3794-3798
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Tidskriftsartikel (refereegranskat)abstract
- Optically active C-2-symmetric (1S,2S,4S,5S)-bicyclo[2.2.2]octane-2,5-diol ((+)-12; 98% ee) and several selectivity protected optically active intermediates useful for synthetic transformations were synthesized via a 1,2-carbonyl transposition route starting from the easily available optically active (1R,4S,6S)-6-hydroxybicyclo[2.2.2]octan-2-one ((-)-2). The synthetic route also allowed the preparation of optically active (1S,4S)-bicyclo[2.2.2]octane-2,5-dione ((+)-14; 98% ee).
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| 8. |
- Bertozzi, Fabio, et al.
(författare)
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Temporary in situ aluminum and zinc tethering in Diels-Alder reactions
- 2000
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 2:9, s. 1283-1286
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Tidskriftsartikel (refereegranskat)abstract
- (formula presented) Temporary tethering using aluminum or zinc in Diels-Alder reactions made possible the use of otherwise "noncompatible" combinations of dienes and dienophiles, resulting in the one-step formation of substituted cyclohexene 1,2-bis-methanols. Excellent regioselectivity and also significant stereoselectivity were obtained.
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| 9. |
- Blomberg, David, 1971-
(författare)
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Synthesis of β-turn and pyridine based peptidomimetics
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Despite the unfavorable pharmacokinetic properties associated with peptides, they are still of great interest in drug development due to a multitude of interesting biological functions. The development of peptidomimetics strives to maintain or improve the biological activity of a peptide concurrently with removing the unwanted properties. This thesis describes two synthetic approaches to peptidomimetics with particular emphasis on secondary structure mimetics. First the design, synthesis and evaluation of two beta-turn mimetics incorporated in the endorphin Leu-enkephalin is presented. The beta-turn mimetics were stabilized by replacement of the intramolecular hydrogen bond with an ethylene bridge, and the amide bond between Tyr and Gly was replaced with an ether linkage. Linear analogues of the two mimetics were also synthesized. The peptidomimetics and their linear analogues were evaluated in a competitive binding assay at two opiate receptors, my and delta. One of the cyclized beta-turn mimetics was found to be a delta receptor antagonist with an IC50 value of 160 nM. Second a synthetic strategy to a beta-strand mimetic using 2-fluoro-4-iodopyridine as scaffold is described. The synthesis involved a Grignard exchange reaction on the pyridine scaffold using an amino acid derivative as electrophile followed by an SNAr reaction using an amine as nucleophile. The synthesis of a tripeptidomimetic of Leu-Gly-Gly and attempts to introduce chiral building blocks at the C-terminal, as well as studies towards elongated mimetics are presented. Two additional studies deal with the synthesis of two classes of potential thrombin inhibitors based on the pyridine scaffold. The first class contain pyridine as central fragment (P2 residue) substituted with a para-amidinobenzylamine group as P1 residue and various benzoyl groups as P3 residues. Three potential thrombin inhibitors were synthesized and found to be microM inhibitors in an enzymatic assay. In the second class, the pyridine ring serves as P3 residue. This class also lacks a strongly basic group in the P1 position. A small library of eight compounds were synthesized and evaluated in the enzymatic assay. Unfortunately, these compounds lacked inhibitory activity.
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| 10. |
- Botes, AL, et al.
(författare)
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Screening of yeast species for the stereo-selective reduction of bicyclo[2.2.2]octane-2,6-dione
- 2002
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Ingår i: Journal of the Chemical Society - Perkin Transactions 1. - : Royal Society of Chemistry (RSC). - 1472-7781 .- 1364-5463. ; :8, s. 1111-1114
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Tidskriftsartikel (refereegranskat)abstract
- Yeast strains from more than 31 different genera were screened for the enantioselective reduction of bicyclo[2.2.2]-octane-2,6-dione (1). Reducing activity was found in 80% of the screened yeasts. Bicyclo[2.2.2]octane-2,6-dione was enantioselectively reduced (> 98% ee) to (1R, 4S, 6S)-6-hydroxybicyclo[2.2.2]octane-2-one (-)-2 by 69% of the strains. Enantioselective reduction of the diketone to (1S, 4R, 6S)-6-hydroxybicyclo[2.2.2]octane-2-one ((+)-3, >98% ee) as a major product is reported for the first time. Candida tropicalis UOFS Y-0534 and Candida wickerhamii UOFS Y-0652 displayed this unusual diastereoselectivity.
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