Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses
Autor(a) principal: | |
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Data de Publicação: | 1999 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Journal of the Brazilian Chemical Society (Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50531999000200014 |
Resumo: | Experiments towards the diastereoselective coupling of new malonic acid amides synthesized with commercially available chiral amines [(S)-(+)-1-cyclohexylethylamine and (R)-(+)-1-phenylethylamine] as chiral auxiliaries were performed through Kolbe oxidations [undivided cell, Pt (anode and cathode), MeOH, 5% to 10% KOH neutralisation, 200 to 250 mA/cm²], using different co-acids (hexanoic, trimethylsilylacetic and diethylphosphonoacetic acids and phthaloylglycine). New long chain and silylated amides (mixed Kolbe dimer) were obtained in good yields (56 to 63%) and low diastereoselectivity, in the presence of a large excess of co-acids, together with disproportionation and non-Kolbe (nK) products, mainly methoxy derivatives. Coupling was more effective with radicals with opposite reactivity. Electrophilic radicals couple between themselves to a lesser extent. Diastereoselective induction was not high. Studies performed with phthaloylglycine, under Kolbe conditions, in the absence and presence of hexanoic acid as a co-acid led to the symmetrical dimer, a N-methoxymethyl-hydroxylactam and a N-methoxyphthalimide. In the presence of hexanoic acid, the latter products were obtained together with alkylated imide and the corresponding hydroxylactam. |
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Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolysesdiastereoselective Kolbe reactionmalonamic acidsphthaloylglycinehydroxylactamExperiments towards the diastereoselective coupling of new malonic acid amides synthesized with commercially available chiral amines [(S)-(+)-1-cyclohexylethylamine and (R)-(+)-1-phenylethylamine] as chiral auxiliaries were performed through Kolbe oxidations [undivided cell, Pt (anode and cathode), MeOH, 5% to 10% KOH neutralisation, 200 to 250 mA/cm²], using different co-acids (hexanoic, trimethylsilylacetic and diethylphosphonoacetic acids and phthaloylglycine). New long chain and silylated amides (mixed Kolbe dimer) were obtained in good yields (56 to 63%) and low diastereoselectivity, in the presence of a large excess of co-acids, together with disproportionation and non-Kolbe (nK) products, mainly methoxy derivatives. Coupling was more effective with radicals with opposite reactivity. Electrophilic radicals couple between themselves to a lesser extent. Diastereoselective induction was not high. Studies performed with phthaloylglycine, under Kolbe conditions, in the absence and presence of hexanoic acid as a co-acid led to the symmetrical dimer, a N-methoxymethyl-hydroxylactam and a N-methoxyphthalimide. In the presence of hexanoic acid, the latter products were obtained together with alkylated imide and the corresponding hydroxylactam.Sociedade Brasileira de Química1999-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50531999000200014Journal of the Brazilian Chemical Society v.10 n.2 1999reponame:Journal of the Brazilian Chemical Society (Online)instname:Sociedade Brasileira de Química (SBQ)instacron:SBQ10.1590/S0103-50531999000200014info:eu-repo/semantics/openAccessGoulart,Marília O.F.Schäfer,Hans-Yürgeneng2002-10-23T00:00:00Zoai:scielo:S0103-50531999000200014Revistahttp://jbcs.sbq.org.brONGhttps://old.scielo.br/oai/scielo-oai.php||office@jbcs.sbq.org.br1678-47900103-5053opendoar:2002-10-23T00:00Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ)false |
dc.title.none.fl_str_mv |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses |
title |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses |
spellingShingle |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses Goulart,Marília O.F. diastereoselective Kolbe reaction malonamic acids phthaloylglycine hydroxylactam |
title_short |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses |
title_full |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses |
title_fullStr |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses |
title_full_unstemmed |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses |
title_sort |
Diastereomeric Amides Derived from Malonic Acid: the Role of Chiral Auxiliaries and of the Nature of Co-Acids in the Mixed Kolbe Electrolyses |
author |
Goulart,Marília O.F. |
author_facet |
Goulart,Marília O.F. Schäfer,Hans-Yürgen |
author_role |
author |
author2 |
Schäfer,Hans-Yürgen |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Goulart,Marília O.F. Schäfer,Hans-Yürgen |
dc.subject.por.fl_str_mv |
diastereoselective Kolbe reaction malonamic acids phthaloylglycine hydroxylactam |
topic |
diastereoselective Kolbe reaction malonamic acids phthaloylglycine hydroxylactam |
description |
Experiments towards the diastereoselective coupling of new malonic acid amides synthesized with commercially available chiral amines [(S)-(+)-1-cyclohexylethylamine and (R)-(+)-1-phenylethylamine] as chiral auxiliaries were performed through Kolbe oxidations [undivided cell, Pt (anode and cathode), MeOH, 5% to 10% KOH neutralisation, 200 to 250 mA/cm²], using different co-acids (hexanoic, trimethylsilylacetic and diethylphosphonoacetic acids and phthaloylglycine). New long chain and silylated amides (mixed Kolbe dimer) were obtained in good yields (56 to 63%) and low diastereoselectivity, in the presence of a large excess of co-acids, together with disproportionation and non-Kolbe (nK) products, mainly methoxy derivatives. Coupling was more effective with radicals with opposite reactivity. Electrophilic radicals couple between themselves to a lesser extent. Diastereoselective induction was not high. Studies performed with phthaloylglycine, under Kolbe conditions, in the absence and presence of hexanoic acid as a co-acid led to the symmetrical dimer, a N-methoxymethyl-hydroxylactam and a N-methoxyphthalimide. In the presence of hexanoic acid, the latter products were obtained together with alkylated imide and the corresponding hydroxylactam. |
publishDate |
1999 |
dc.date.none.fl_str_mv |
1999-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50531999000200014 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50531999000200014 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0103-50531999000200014 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Química |
publisher.none.fl_str_mv |
Sociedade Brasileira de Química |
dc.source.none.fl_str_mv |
Journal of the Brazilian Chemical Society v.10 n.2 1999 reponame:Journal of the Brazilian Chemical Society (Online) instname:Sociedade Brasileira de Química (SBQ) instacron:SBQ |
instname_str |
Sociedade Brasileira de Química (SBQ) |
instacron_str |
SBQ |
institution |
SBQ |
reponame_str |
Journal of the Brazilian Chemical Society (Online) |
collection |
Journal of the Brazilian Chemical Society (Online) |
repository.name.fl_str_mv |
Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ) |
repository.mail.fl_str_mv |
||office@jbcs.sbq.org.br |
_version_ |
1750318163752386560 |