- First isolation of both indolylcarbinols and diindolylalkanes from microwave-assisted acid (clay)-catalysed reaction of indoles with diethyl ketomalonate
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Indoles (1a-f) react with diethyl ketomalonate on montmorillonite K10 clay under microwave irradiation to furnish expeditiously (1-4 min) the corresponding indol-3′-ylcarbinols (2a-f; 20-45%) and the respective diindolylalkanes (3a-f; 5-35%), which constitute the first direct evidence for the intermediacy of indolylcarbinols in the formation of diindolylalkanes from the acid-catalysed reaction of indoles with aldehydes and ketones.
- Chakrabarty, Manas,Karmakar, Sulakshana,Harigaya, Yoshihiro
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- First reactions of 2,2'-bisindolyls with electrophilic azo compounds and diethyl mesoxalate
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Conformations and some electronic properties of the 2,2'-bisindolyls 6 were calculated for the prediction of probable Diels-Alder reactivity, in analogy to previous work on 2-vinylindoles. First reactions with dienophiles revealed that compounds 6 did not participate in [4 + 2]cycloadditions but rather underwent simple electrophilic substitutions at the enamine function with, above all, some heterodienophiles.
- Pindur,Kim
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p. 353 - 356
(2007/10/02)
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- FIRST REACTIONS OF VINYLINDOLES WITH DIETHYL MESOXALATE, NITROSOBENZENE, AND CHLOROSULFONYL ISOCYANATE: NEW FUNCTIONALIZED AND ANNELLATED INDOLES
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Diethyl mesoxalate reacts with 2- and 3-vinylindoles via electrophilic substitution to give new, functionalized and annellated indoles in high regioselectivities.Regio-controlled dimerization processes occur in the reactions of the vinylindoles 5a and 8a.Nitrosobenzene reacts with 2- and 3-vinylindoles in a multi-stage sequence including regiospecific tandem hetero-Diels-Alder reactions to give the new, 2,3-difunctionalized indoles 11 and 12 which are conformationally stabilized by proton chelation.The heterocumulenechlorosulfonyl isocyanate reacts as a simple electrophile (like diethyl mesoxalate) with 2-vinylindole 5b to give the indole-3-carboxamide 14.In addition, analogous reactions of N-methylindole were also studied and, in most cases, gave comparable reactivity patterns.
- Pindur, Ulf,Kim, Myung-Hwa
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p. 6427 - 6438
(2007/10/02)
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