- Polystyrene-immobilized DABCO as a highly efficient and recyclable organocatalyst for the Knoevenagel condensation reaction
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Polystyrene-immobilized DABCO was used for the first time as a basic organocatalyst for carbon-carbon bond formation reactions. The supported catalyst could be used as a reusable catalyst in the Knoevenagel condensation of a wide range of aromatic/heterocyclic/α,β-unsaturated aldehydes and ketones with active methylene compounds. The reaction conditions are mild and the method is operationally simple. The reactions proceed in a short time period and with 100% selectivity. The catalyst could be easily separated from the reaction by filtration and recycled ten times without activity loss. Based on the catalyst, a continuous flow process was also developed.
- Xu, Da-Zhen,Shi, Sen,Wang, Yongmei
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- Spiranes 6. Ring A homologues of N-benzyloxy-2-azaspiro[4.4]nonane-1,3-dione. Synthesis, X-ray analysis and anticonvulsant evaluation
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A series of spirosuccinimides was synthesized and evaluated for anticonvulsant activity. The study was designed to determine the effect of varying the carbocyclic (ring A) nucleus, while maintaining the heterocyclic ring constant, on anticonvulsant activity. Results indicate that maximum activity was obtained with the ring A comprised of a six-membered spiro ring system, 2a, one methylene group greater than that previously reported for N-(benzyloxy)-2-azaspiro[4.4]nonane-1,3-dione, 1, the prototype analogue. Compound 2a was active in the MES test providing protection at 100 mg/kg, as was the spirododecane analog 2g. X-ray analysis revealed significant differences between active 2a, and the inactive spirooctane analogue, 2f. However these differences could not explain the unexpected activity demonstrated by the spirododecane analog 2g.
- Alexander,Stables,Ciechanowicz-Rutkowska,Hursthouse,Hibbs,Edafiogho,Farrar,Moore,Scott
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- The stereoselective addition of organometallic reagents to electron-deficient alkylidenecyclohexanes; alternative linkages for cholaphane synthesis
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Knoevenagel condensations between t-butylcyclohexanone and malononitrile, Meldrum's acid and ethyl cyanoacetate gave electron-deficient alkenes which underwent equatorial-selective attack by chemoselective aryl organometallic reagents. Further transformat
- Davis, Anthony P.,Egan, Thomas J.,Orchard, Michael G.,Cunningham, Desmond,McArdle, Patrick
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p. 8725 - 8738
(2007/10/02)
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- Antiarthritic and suppressor cell inducing activity of azaspiranes: Structure-function relationships of a novel class of immunomodulatory agents
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Spirogermanium (1;8,8-diethyl-N,N-dimethyl-2-aza-8-germaspiro[4.5]decane-2-propanamin e dihydrochloride) is a potent cytotoxic agent in vitro which has demonstrated limited activity in experimental animal tumor models. Subsequently, it has been reported that spirogermanium has antiarthritic and suppressor cell-inducing activity. We have synthesized a series of substituted 8-hetero-2-azaspiro[4.5]decane and 9-hetero-3-azaspiro[5.5]undecane analogues of spirogermanium to identify the heteroatom requirements for in vivo antiarthritic and suppressor cell-inducing activity. This structure-activity relationship study has identified that appropriately substituted silicon and carbon analogues of spirogermanium retain both antiarthritic and immunosuppressive activity, with the 8,8-dipropyl (carbon) analogue being among the most active. Following the identification of N,N-dimethyl-8,8-dipropyl-2-azaspiro[4,5]decane-2-propanamine dihydrochloride (9) as more active analogue than spirogermanium, a series of 8,8-dipropyl analogues with various amine substituents were synthesized. A number of these analogues had activity similar to that of 9. A correlation between activity in the adjuvant arthritic rat and the ability to induce suppressor cells (r = 0.894, p0.001) suggests an association between the two pharmacologic effects. While the precise biochemical mechanism(s) for the pharmacological activity is unclear, these data suggest that compounds within this series, e.g., N,N-dimethyl-8,8-dipropyl-2-azaspiro[4.5]decane-2-propanamine dihydrochloride, may provide effective therapy in diseases of autoimmune origin and/or the prevention of rejection in tissue transplantation.
- Badger,Schwartz,Picker,Dorman,Bradley,Cheeseman,DiMartino,Hanna,Mirabelli
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p. 2963 - 2970
(2007/10/02)
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