- An easy ABD→ABCD strategy to indolo[2,3-a]quinolizin-4-one. Synthesis of deplancheine and yohimbane
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The efficient synthesis of indolo[2,3-a]quinolizin-4-ones 2 is described in two steps via formal [3+3] cycloaddition reaction of α-sulfonyl tryptaminylacetamide 4 with various α,β-unsaturated esters 5 and the regioselective reduction of the resulting glut
- Chang, Meng-Yang,Chen, Chung-Yi,Chung, Wen-Shang,Tasi, Min-Ruei,Chang, Nein-Chen
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p. 585 - 591
(2007/10/03)
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- Regioselective reduction of N-alkyl-3-sulfonylglutarimide. Formal synthesis of 1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizine and homobaclofen
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Reduction of N-alkyl-3-sulfonylglutarimides with (1) sodium hydride and then with lithium aluminum hydride, or (2) sodium borohydride yielded two different types of regioselectively reduced hydroxypiperidinones which were further dehydrated to two pyridin-2-ones in the presence of boron trifluoride etherate. Cycloaddition and regioselective reduction were combined to synthesize 1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizine and homobaclofen.
- Chang, Meng-Yang,Chen, Shui-Tein,Chang, Nein-Chen
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- One-pot facile conversion of Baylis-Hillman adduct into N-alkyl 3-(E)-alkylidene-5-substituted sulfonylpiperidine-2,6-dione. Formal synthesis of tacamonine
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A stepwise [3+3] strategy to N-alkyl 3-(E)-alkylidene-5-substituted sulfonylpiperidine-2,6-dione 1 used various N-alkyl α-substituted sulfonylacetamides 2 and α,β-unsaturated esters 3 as starting materials. α,β-Unsaturated esters 3 were generated by Baylis-Hillman reaction. A ring closure mechanism was proposed for the reactions. This method provides a convenient formal synthesis of tacamonine.
- Chen, Chung-Yi,Chang, Meng-Yang,Hsu, Ru-Ting,Chen, Shui-Tein,Chang, Nein-Chen
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p. 8627 - 8630
(2007/10/03)
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- Reaction of different α-sulfonyl acetamides with methyl acrylate
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The base-induced tandem-coupling/cyclization reactions of various α-sulfonyl acetamide derivatives A with methyl acrylate differentiated between two different pathways to form α-sulfonyl analogs of glutarimides B and 2-hydroxycyclohexenecarboxylic acid derivatives C in different ratios. The reaction of α-sulfonyl acetamide dianion with methyl acrylate depended on three factors: the stability of the dianion, concentration of methyl acrylate and the structure of sufonyl and amide substituents. By changing the reaction conditions, we efficiently controlled the cycloaddition reaction to synthesize the desired product, each of which has potential biological activities. A ring closure mechanism is proposed for the reactions.
- Chang, Meng-Yang,Chen, Shui-Tein,Chang, Nein-Chen
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p. 5075 - 5080
(2007/10/03)
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