| 1. |
- Carlsson, Anna-Carin, 1976, et al.
(author)
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Microwave-assisted synthesis of the Schollkopf chiral auxiliaries: (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine
- 2006
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In: Tetrahedron Letters. - : Elsevier BV. - 0040-4039. ; 47:29, s. 5199-5201
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Journal article (peer-reviewed)abstract
- A practical and efficient methodology for the laboratory scale preparation of Schollkopf's bis-lactim ether chiral auxiliaries (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine has been developed. The key step is the preparation of the 2,5diketopiperazine derivative by microwave-assisted heating in water. The protocol avoids reactions at low temperature and the use of high boiling solvents. Only inexpensive and readily available starting materials are required. The bis-lactim ethers were produced in high yields on a multigram scale. (c) 2006 Elsevier Ltd. All rights reserved.
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| 2. |
- Dahlén, Kristian, 1973, et al.
(author)
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A scaffold approach to 3,6,8-trisubstituted flavones
- 2006
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In: Synlett. - : Georg Thieme Verlag KG. - 0936-5214 .- 1437-2096. ; :6, s. 897-900
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Journal article (peer-reviewed)abstract
- An efficient synthetic approach to 3,6,8-trisubstituted flavone scaffolds has been developed based on Pd-mediated coupling reactions.
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| 3. |
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| 4. |
- Dahlén, Kristian, 1973, et al.
(author)
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Synthesis of 2,3,6,8-tetrasubstituted chromone scaffolds.
- 2006
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In: The Journal of organic chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 71:18, s. 6863-6871
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Journal article (peer-reviewed)abstract
- A useful and efficient synthetic strategy to 2,3,6,8-tetrasubstituted chromone derivatives has been developed. 2-Aryl/styryl-8-bromo-6-chloro-3-hydroxychromone derivatives were synthesized and used as scaffolds by introducing a variety of substituents in the 3-, 6-, and 8-positions using palladium-mediated reactions. Excellent regioselectivity in all positions could be obtained by performing reactions in the 8-position first, in which Stille, Heck, Suzuki, and Sonogashira reactions gave good to excellent yields of product (63-98%). Stille and Heck reactions in the 6-position also gave the desired products in good yields (64-86%). The hydroxy group in the 3-position was activated as a triflate and used in productive Stille reactions (63-94%). This hydroxyl group was also used in O-alkylation reactions with different functionalized alkyl bromides (57-88%). The flavonoids, which are based on the chromone structure, and other related ring systems, have several interesting biological activities. The chromones are also interesting structural scaffolds, and they have for example been designed to be used as mimetics of short peptides. The versatile applicability of chromone derivatives and especially their potential use in drug discovery implicates the importance of access to efficient synthetic routes to such compounds.
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| 5. |
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| 6. |
- Dinér, Peter, 1976, et al.
(author)
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Short cut to 1,2,3-triazole-based p38 MAP kinase inhibitors via [3+2]-cycloaddition chemistry
- 2009
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In: New J. Chem.. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:5, s. 1010-1016
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Journal article (peer-reviewed)abstract
- A series of 4,5-substituted 1,2,3-triazoles was synthesised via Cu(I)-catalysed azide–alkyne 1,3-dipolar [2+3]-cycloaddition reactions followed by a Suzuki coupling. The 1,2,3-triazoles were evaluated as inhibitors of the p38 MAP kinase, showing IC50 values in the high nanomolar range
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| 7. |
- Dyrager, Christine, 1975, et al.
(author)
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2,6,8-Trisubstituted 3-hydroxychromone derivatives as fluorophores for live-cell imaging.
- 2009
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In: Chemistry (Weinheim an der Bergstrasse, Germany). - : Wiley. - 1521-3765 .- 0947-6539. ; 15:37, s. 9417-23
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Journal article (peer-reviewed)abstract
- We present the synthesis and photophysical characterisation of a series of structurally diverse, fluorescent 2,6,8-trisubstituted 3-hydroxychromone derivatives with high fluorescence quantum yields and molar extinction coefficients. Two of these derivatives (9 and 10 a) have been studied as fluorophores for cellular imaging in HeLa cells and show excellent permeability and promising fluorescence properties in a cellular environment. In addition, we have demonstrated by photophysical characterisation of 3-isobutyroxychromone derivatives that esterification of the 3-hydroxyl group results in acceptable and useful fluorescence properties.
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| 8. |
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| 9. |
- Fridén-Saxin, Maria, 1979, et al.
(author)
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Synthesis of 2-alkyl-substituted chromone derivatives using microwave irradiation.
- 2009
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In: The Journal of organic chemistry. - : American Chemical Society (ACS). - 1520-6904 .- 0022-3263. ; 74:7, s. 2755-9
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Journal article (peer-reviewed)abstract
- A base-promoted condensation between 2-hydroxyacetophenones and aliphatic aldehydes has been studied. The reaction has been optimized to afford 2-alkyl-substituted 4-chromanones in an efficient manner using microwave heating. Performing the reaction using diisopropylamine in EtOH at 170 degrees C for 1 h gave moderate to high yields (43-88%). The 4-chromanones could be further converted into highly functionalized 2,3,6,8-tetrasubstituted chromones in which a 3-substituent (acetate, amine, or bromine) was introduced via straightforward chemical transformations.
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| 10. |
- Galanis, Athanassios S, et al.
(author)
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Enhanced microwave-assisted method for on-bead disulfide bond formation: synthesis of alpha-conotoxin MII.
- 2009
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In: Biopolymers. - : Wiley. - 0006-3525 .- 1097-0282. ; 92:1, s. 23-34
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Journal article (peer-reviewed)abstract
- A novel enhanced microwave-assisted disulfide bridge formation method has been developed. To optimize the synthesis of the biologically important bicyclic peptide alpha-conotoxin MII (alpha-CtxMII), several cyclization methods have been tested and are discussed herein. By using m.w.-assisted heating, we achieved high yields for the first loop cyclization of alpha-CtxMII on-bead. This method has the advantage of avoiding intermolecular by-products during the cyclization step. Furthermore, the method gives higher yields compared with the common on-bead cyclization methods. The second disulfide bridge of alpha-CtxMII was formed using a simple oxidation method after the cleavage of the intermediate monocyclic peptide from the resin. This method has the potential to be efficient for the synthesis of other disulfide rich biologically important peptides.
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