A. Meijere - Academia.edu (original) (raw)
Papers by A. Meijere
The Journal of Organic Chemistry, 1999
Methyl 2-chloro-2-cyclopropylideneacetate (2) and its spiropentane analogue 3 cycloadd to dihydro... more Methyl 2-chloro-2-cyclopropylideneacetate (2) and its spiropentane analogue 3 cycloadd to dihydroisoquinoline N-oxide (9), pyrroline N-oxide (12), and C-phenyl-N-methylnitrone (16) to give 5-spirocyclopropaneisoxazolidines in good yields (58-93%). The thermal behavior of the 5-spirocyclopropaneisoxazolidines is rather differentiated, depending strongly on the constitution of the nitrone and the solvent. As nitrone 9 has the tendency to undergo cycloreversion reactions, the ketoamide rearrangement products 20 and 21 from its cycloadduct derive from the thermodynamically favored 4-spirocyclopropaneisoxazolidine regioisomers formed after the cycloreversion process. In DMSO as solvent different rearrangement processes take place, leading to benzoindolizinones in modest yields (15-21%). The cycloadducts from 12 and 16 undergo a cyclopropyl to cyclobutyl ring enlargement facilitated by the presence of a chlorine substituent on the carbon alpha to the spirocyclopropane ring. Whereas these compounds from nitrone 16 demonstrated an unusual stability, those from nitrone 12 undergo a cascade rearrangement to yield indolizinone derivatives 34, 35 cleanly (73-83% yield). This overall transformation offers a new method for the synthesis of the indolizine skeleton.
Chemistry - A European Journal, 2001
Angewandte Chemie International Edition in English, 1982
bond in 4 fulfills several useful functions by (i) providing a site for silver nitrate complexati... more bond in 4 fulfills several useful functions by (i) providing a site for silver nitrate complexation, thus allowing easy separation, purification and storage of oily 4 ; (ii) introducing tricyclic strain, thus holding the labile rnethylene double bond in the exo-position, without danger of isomerization into the otherwise more stable endocyclic 5,6-p0sition~'~.~]; (iii) allowing access to new analogues of zizaene which have not yet been encountered in any natural products.
Chemische Berichte, 1983
ABSTRACT
European Journal of Organic Chemistry, 1999
ABSTRACT
European Journal of Organic Chemistry, 2003
ABSTRACT
Journal of Molecular Structure, 2004
(1-Fluorocyclopropyl)methanol has been studied by microwave spectroscopy in the 12-61 GHz spectra... more (1-Fluorocyclopropyl)methanol has been studied by microwave spectroscopy in the 12-61 GHz spectral region. The rotational spectra of the ground and of four vibrationally excited states belonging to three different normal modes of one rotamer have been assigned. Most other cyclopropylmethanol derivatives prefer conformations stabilized by an internal hydrogen bond with the pseudo-p electrons along the edges of the ring. This is not the case for the title compound. The conformer assigned in this work has an internal hydrogen bond formed between the fluorine atom and the hydrogen atom of the hydroxyl group. This rotamer is at least 4 kJ/mol more stable than any other form of the molecule. It is pointed out that electrostatic interaction between the O-H and C-F bond dipoles can largely explain the conformational preference of this compound. The microwave work has been assisted by gas-phase infrared spectroscopy and quantum chemical calculations made at the MP2/6-311þþG** and B3LYP/6-311þþG** levels of theory.
The series Topics in Current Chemistry presents critical reviews of the present and future trends... more The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage in-cludes all areas of chemical science including the interfaces with related dis-ciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the nonspecialist reader, whether at the university or in industry, a comprehensive overview of an area where new insights are emerging that are of interest to a larger scientific audience. As a rule, contributions are specially commissioned. The editors and publish-ers will, however, always be pleased to receive suggestions and supplementary
Angewandte Chemie, 1997
... Peter Prinz, Annegret Lansky, Thomas Haumann, Roland Boese, Matthias Noltemeyer, Burkhard Kni... more ... Peter Prinz, Annegret Lansky, Thomas Haumann, Roland Boese, Matthias Noltemeyer, Burkhard Knieriem und Armin de Meijere* Professor Fabian Gerson gewidmet ... Curr. Chem. 1992, 160, 47-95. [4] a) R. Diercks, JC Armstrong, R. Boese, KPC Vollhardt, Angew. Chem. ...
European Journal of Organic Chemistry, 2005
ABSTRACT An easy and efficient synthesis of valylleucyl anilide (HValLeuNHPh) and labelled HVal(1... more ABSTRACT An easy and efficient synthesis of valylleucyl anilide (HValLeuNHPh) and labelled HVal(13C5,15N)LeuNHPh has been developed. Derivatization of these substances with oxirane, acrylonitrile, epichlorohydrin, glyceraldehyde and other aldehydes gives a series of reference substances and internal standards for the quantitative evaluation of human exposure to toxic electrophiles by quantitative determination of their hemoglobin adducts. Coupling of N-Z-N-Me-Val(13C5,15N)OH with HLeuNHPh followed by hydrogenolysis affords N–Me–Val(13C5,15N)LeuNHPh for quantification of the exposure to methylating agents. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Angewandte Chemie International Edition in English, 1993
Beilstein journal of organic chemistry, 2017
A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular-ar... more A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular-arylation of tertiary 1-(methoxycarbonyl)methanesulfonamides under palladium catalysis is described. In case of the α-toluenesulfonamide derivative, an unexpected formation of a 2,3-diarylindole was observed under the same conditions.
Journal of natural products, Jan 17, 2016
An original synthesis of the acetogenin muricadienin, the bioprecursor of solamin, has been devel... more An original synthesis of the acetogenin muricadienin, the bioprecursor of solamin, has been developed. The key step in the five-step 41% overall yield synthesis is the catalytic cross-cyclomagnesiation reaction of functionally substituted 1,2-dienes with EtMgBr in the presence of Cp2TiCl2 and magnesium metal. It has been demonstrated for the first time that muricadienin exhibits a moderate in vitro inhibitory activity against topoisomerases I and IIα, key cell cycle enzymes. Using flow cytometry, muricadienin was shown to have high cytotoxicity toward the HEK293 kidney cancer cells (IC50 0.39 μM).
Nachr Chem Technik Lab, 2010
Http Www Libreriasaulamedica Com, 1998
Http Www Libreriasaulamedica Com, 2010
The Journal of Organic Chemistry, 1999
Methyl 2-chloro-2-cyclopropylideneacetate (2) and its spiropentane analogue 3 cycloadd to dihydro... more Methyl 2-chloro-2-cyclopropylideneacetate (2) and its spiropentane analogue 3 cycloadd to dihydroisoquinoline N-oxide (9), pyrroline N-oxide (12), and C-phenyl-N-methylnitrone (16) to give 5-spirocyclopropaneisoxazolidines in good yields (58-93%). The thermal behavior of the 5-spirocyclopropaneisoxazolidines is rather differentiated, depending strongly on the constitution of the nitrone and the solvent. As nitrone 9 has the tendency to undergo cycloreversion reactions, the ketoamide rearrangement products 20 and 21 from its cycloadduct derive from the thermodynamically favored 4-spirocyclopropaneisoxazolidine regioisomers formed after the cycloreversion process. In DMSO as solvent different rearrangement processes take place, leading to benzoindolizinones in modest yields (15-21%). The cycloadducts from 12 and 16 undergo a cyclopropyl to cyclobutyl ring enlargement facilitated by the presence of a chlorine substituent on the carbon alpha to the spirocyclopropane ring. Whereas these compounds from nitrone 16 demonstrated an unusual stability, those from nitrone 12 undergo a cascade rearrangement to yield indolizinone derivatives 34, 35 cleanly (73-83% yield). This overall transformation offers a new method for the synthesis of the indolizine skeleton.
Chemistry - A European Journal, 2001
Angewandte Chemie International Edition in English, 1982
bond in 4 fulfills several useful functions by (i) providing a site for silver nitrate complexati... more bond in 4 fulfills several useful functions by (i) providing a site for silver nitrate complexation, thus allowing easy separation, purification and storage of oily 4 ; (ii) introducing tricyclic strain, thus holding the labile rnethylene double bond in the exo-position, without danger of isomerization into the otherwise more stable endocyclic 5,6-p0sition~'~.~]; (iii) allowing access to new analogues of zizaene which have not yet been encountered in any natural products.
Chemische Berichte, 1983
ABSTRACT
European Journal of Organic Chemistry, 1999
ABSTRACT
European Journal of Organic Chemistry, 2003
ABSTRACT
Journal of Molecular Structure, 2004
(1-Fluorocyclopropyl)methanol has been studied by microwave spectroscopy in the 12-61 GHz spectra... more (1-Fluorocyclopropyl)methanol has been studied by microwave spectroscopy in the 12-61 GHz spectral region. The rotational spectra of the ground and of four vibrationally excited states belonging to three different normal modes of one rotamer have been assigned. Most other cyclopropylmethanol derivatives prefer conformations stabilized by an internal hydrogen bond with the pseudo-p electrons along the edges of the ring. This is not the case for the title compound. The conformer assigned in this work has an internal hydrogen bond formed between the fluorine atom and the hydrogen atom of the hydroxyl group. This rotamer is at least 4 kJ/mol more stable than any other form of the molecule. It is pointed out that electrostatic interaction between the O-H and C-F bond dipoles can largely explain the conformational preference of this compound. The microwave work has been assisted by gas-phase infrared spectroscopy and quantum chemical calculations made at the MP2/6-311þþG** and B3LYP/6-311þþG** levels of theory.
The series Topics in Current Chemistry presents critical reviews of the present and future trends... more The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage in-cludes all areas of chemical science including the interfaces with related dis-ciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the nonspecialist reader, whether at the university or in industry, a comprehensive overview of an area where new insights are emerging that are of interest to a larger scientific audience. As a rule, contributions are specially commissioned. The editors and publish-ers will, however, always be pleased to receive suggestions and supplementary
Angewandte Chemie, 1997
... Peter Prinz, Annegret Lansky, Thomas Haumann, Roland Boese, Matthias Noltemeyer, Burkhard Kni... more ... Peter Prinz, Annegret Lansky, Thomas Haumann, Roland Boese, Matthias Noltemeyer, Burkhard Knieriem und Armin de Meijere* Professor Fabian Gerson gewidmet ... Curr. Chem. 1992, 160, 47-95. [4] a) R. Diercks, JC Armstrong, R. Boese, KPC Vollhardt, Angew. Chem. ...
European Journal of Organic Chemistry, 2005
ABSTRACT An easy and efficient synthesis of valylleucyl anilide (HValLeuNHPh) and labelled HVal(1... more ABSTRACT An easy and efficient synthesis of valylleucyl anilide (HValLeuNHPh) and labelled HVal(13C5,15N)LeuNHPh has been developed. Derivatization of these substances with oxirane, acrylonitrile, epichlorohydrin, glyceraldehyde and other aldehydes gives a series of reference substances and internal standards for the quantitative evaluation of human exposure to toxic electrophiles by quantitative determination of their hemoglobin adducts. Coupling of N-Z-N-Me-Val(13C5,15N)OH with HLeuNHPh followed by hydrogenolysis affords N–Me–Val(13C5,15N)LeuNHPh for quantification of the exposure to methylating agents. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Angewandte Chemie International Edition in English, 1993
Beilstein journal of organic chemistry, 2017
A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular-ar... more A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular-arylation of tertiary 1-(methoxycarbonyl)methanesulfonamides under palladium catalysis is described. In case of the α-toluenesulfonamide derivative, an unexpected formation of a 2,3-diarylindole was observed under the same conditions.
Journal of natural products, Jan 17, 2016
An original synthesis of the acetogenin muricadienin, the bioprecursor of solamin, has been devel... more An original synthesis of the acetogenin muricadienin, the bioprecursor of solamin, has been developed. The key step in the five-step 41% overall yield synthesis is the catalytic cross-cyclomagnesiation reaction of functionally substituted 1,2-dienes with EtMgBr in the presence of Cp2TiCl2 and magnesium metal. It has been demonstrated for the first time that muricadienin exhibits a moderate in vitro inhibitory activity against topoisomerases I and IIα, key cell cycle enzymes. Using flow cytometry, muricadienin was shown to have high cytotoxicity toward the HEK293 kidney cancer cells (IC50 0.39 μM).
Nachr Chem Technik Lab, 2010
Http Www Libreriasaulamedica Com, 1998
Http Www Libreriasaulamedica Com, 2010