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Moses Lee - One of the best experts on this subject based on the ideXlab platform.
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an efficient synthesis of furano analogs of duocarmycin c1 and c2 seco iso cyclopropylfurano e indoline trimethoxyindole and seco cyclopropylfurano f quinoline trimethoxyindole
Tetrahedron Letters, 2014Co-Authors: Pravin C Patil, Moses LeeAbstract:seco-Iso-cyclopropylfurano[e]indoline-trimethoxyindole 1 and seco-cyclopropylfurano[f]quinoline-trimethoxyindole 2 are potent cytotoxic agents. Previous synthesis of these compounds was inefficient and the approach required separation of a mixture containing the isomeric indoline and quinoline intermediates 11 and 12, formed from radical cyclization of allylic bromide 10. Reported herein is an efficient and selective synthesis of either intermediate 11 or 12, thus product 1 or 2, as needed. The conditions of the Stobbe Condensation, bromination, 5-exo-trig radical cyclization, amine-carboxylic acid coupling, and debenzylation were optimized for multi gram scale. As a result, the reaction times were shortened, the products were readily isolated, and the yields and purity improved.
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Efficient synthesis of achiral seco-cyclopropylbenz[2,3-e]indoline analogues: [4-amino-2-(5,6,7-trimethoxyindole-2-carboxamido)naphthalen-1-yl]ethyl chloride and [4-hydroxy-2-(5,6,7-trimethoxyindole-2-carboxamido)naphthalen-1-yl]ethyl chloride.
The Journal of organic chemistry, 2006Co-Authors: Atsushi Sato, Adrienne E. Scott, Tetsuji Asao, Moses LeeAbstract:Achiral seco-aminocyclopropylbenz[2,3-e]indoline and seco-hydroxycyclopropylbenz[2,3-e]indoline (seco-CBI) analogues of the duocarmycins and CC-1065, e.g., 7 and 8, are potent anticancer agents. This paper describes significantly improved synthetic strategies for preparing these compounds. Starting from Martius acid (9), the new strategy gave a 13-fold increase in the overall yield of 7, and the use of di-tert-butyl malonate was economically beneficial. For compound 8, the new strategy employed an Emmons−Horner reaction, followed by a Stobbe Condensation, and the overall yield was improved 15-fold.
Guido H Daub - One of the best experts on this subject based on the ideXlab platform.
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the Stobbe Condensation
Organic Reactions, 2011Co-Authors: William S Johnson, Guido H DaubAbstract:In 1893, Stobbe demonstrated that when a mixture of acetone and diethyl succinate was treated with sodium ethoxide the expected acetoacetic ester type of Condensation to give beta-diketo compound did not take place. The reaction of aldehydes or ketones with an ester of succinic acid to form alkylidenesuccinic acid, or isomers formed by a tautomeric shift of hydrogen, is known as the Stobbe Condensation. One mole of metal alkoxide is required per mole of carbonyl compound and ester, and the primary product is the salt of the half-ester. Keywords: Stobbe Condensation; aldehydes; ketones; diketones; keto esters; cyano ketones; isolation of products; substituted succinic esters; side reactions; experimental procedures
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Organic Reactions - The Stobbe Condensation
Organic Reactions, 2011Co-Authors: William S Johnson, Guido H DaubAbstract:In 1893, Stobbe demonstrated that when a mixture of acetone and diethyl succinate was treated with sodium ethoxide the expected acetoacetic ester type of Condensation to give beta-diketo compound did not take place. The reaction of aldehydes or ketones with an ester of succinic acid to form alkylidenesuccinic acid, or isomers formed by a tautomeric shift of hydrogen, is known as the Stobbe Condensation. One mole of metal alkoxide is required per mole of carbonyl compound and ester, and the primary product is the salt of the half-ester. Keywords: Stobbe Condensation; aldehydes; ketones; diketones; keto esters; cyano ketones; isolation of products; substituted succinic esters; side reactions; experimental procedures
William S Johnson - One of the best experts on this subject based on the ideXlab platform.
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the Stobbe Condensation
Organic Reactions, 2011Co-Authors: William S Johnson, Guido H DaubAbstract:In 1893, Stobbe demonstrated that when a mixture of acetone and diethyl succinate was treated with sodium ethoxide the expected acetoacetic ester type of Condensation to give beta-diketo compound did not take place. The reaction of aldehydes or ketones with an ester of succinic acid to form alkylidenesuccinic acid, or isomers formed by a tautomeric shift of hydrogen, is known as the Stobbe Condensation. One mole of metal alkoxide is required per mole of carbonyl compound and ester, and the primary product is the salt of the half-ester. Keywords: Stobbe Condensation; aldehydes; ketones; diketones; keto esters; cyano ketones; isolation of products; substituted succinic esters; side reactions; experimental procedures
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Organic Reactions - The Stobbe Condensation
Organic Reactions, 2011Co-Authors: William S Johnson, Guido H DaubAbstract:In 1893, Stobbe demonstrated that when a mixture of acetone and diethyl succinate was treated with sodium ethoxide the expected acetoacetic ester type of Condensation to give beta-diketo compound did not take place. The reaction of aldehydes or ketones with an ester of succinic acid to form alkylidenesuccinic acid, or isomers formed by a tautomeric shift of hydrogen, is known as the Stobbe Condensation. One mole of metal alkoxide is required per mole of carbonyl compound and ester, and the primary product is the salt of the half-ester. Keywords: Stobbe Condensation; aldehydes; ketones; diketones; keto esters; cyano ketones; isolation of products; substituted succinic esters; side reactions; experimental procedures
Dale L. Boger - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and Properties of Substituted CBI Analogs of CC-1065 and the Duocarmycins Incorporating the 7-Methoxy-1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (MCBI) Alkylation Subunit: Magnitude of Electronic Effects on the Functional Reactivity
The Journal of organic chemistry, 1996Co-Authors: Dale L. Boger, Jeffrey A. Mckie, Hui Cai, Barbara Cacciari, P. G. BaraldiAbstract:The synthesis of 7-methoxy-1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (MCBI), a substituted CBI derivative bearing a C7 methoxy group para to the C4 carbonyl, is described in efforts that establish the magnitude of potential electronic effects on the chemical and functional reactivity of the agents. The core structure of the MCBI alkylation subunit was prepared by a modified Stobbe Condensation/Friedel−Crafts acylation for generation of the appropriately functionalized naphthalene precursors (15 and 20) followed by 5-exo-trig aryl radical−alkene cyclization (24 → 25, 32 → 33) for completion of the synthesis of the 1,2-dihydro-3H-benz[e]indole skeleton and final Ar-3‘ alkylation of 28 for introduction of the activated cyclopropane. Two approaches to the implementation of the key 5-exo-trig free radical cyclization are detailed with the former proceeding with closure of 24 to provide 25 in which the required product functionalization was introduced prior to cyclization and the latter with Tempo trap...
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Synthesis, Chemical Properties, and Preliminary Evaluation of Substituted CBI Analogs of CC-1065 and the Duocarmycins Incorporating the 7-Cyano-1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one Alkylation Subunit: Hammett Quantitation of the Magnitu
The Journal of Organic Chemistry, 1996Co-Authors: Dale L. Boger, Hui Cai, Nianhe Han, Christine M. Tarby, Christopher W. Boyce, Qing Jin, Paul A. KitosAbstract:The synthesis of 7-cyano-1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (CCBI), a substituted CBI derivative bearing a C7 cyano group, is described in efforts that establish the magnitude of potential electronic effects on the functional reactivity of the agents. The CCBI alkylation subunit was prepared by a modified Stobbe Condensation/Friedel−Crafts acylation for generation of the appropriately functionalized naphthalene precursors followed by 5-exo-trig aryl radical−alkene cyclization for synthesis of the 1,2-dihydro-3H-benz[e]indole skeleton and final Ar-3‘ alkylation for introduction of the activated cyclopropane. The most concise approach provided the CCBI subunit and its immediate precursor in 14−15 steps in superb overall conversions (15−20%). Resolution of an immediate CCBI precursor and its incorporation into both enantiomers of 34−39, analogs of CC-1065 and the duocarmycins, are detailed. A study of the solvolysis reactivity and regioselectivity of N-BOC-CCBI (25) revealed that introduction...
Fumio Toda - One of the best experts on this subject based on the ideXlab platform.
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Selective Stobbe Condensation under solvent-free conditions
Green Chemistry, 2000Co-Authors: Koichi Tanaka, Teizo Sugino, Fumio TodaAbstract:Solvent-free Condensation of cyclohexanone (1) and diethyl succinate (2) in the presence of ButOK at room temperature gives cyclohexylidenesuccinic acid (3), while heating a mixture of 1, 2 and ButOK at 80 °C gives only cyclohexenylsuccinic acid (4).