Letters in Organic Chemistry, Volume 1, No. 2, 2004
Contents
Cobalt-Catalyzed Allylation of Aldimines by Allylic
Acetates Pp.105-108
Paulo
Gomes, Corinne Gosmini and Jacques
Perichon
Nucleophilic Additions of Niobium Enolates of
Oxazolidinones to Aromatic Aldehydes and Aldimines Pp.109-111
Carlos
Kleber Z. Andrade, Patricia P. Kalil, Rafael O. Rocha, Luana M. Alves and Curt
M. A. Panisset
Synthesis of p-Conjugated Systems from
Methyldiazines and Aromatic Aldehydes under PTC Conditions and without Organic
Solvent Pp.112-118
Laurent
Pascal, Jean Jacques Vanden Eynde, Yves Van Haverbeke and Philippe Dubois
Palladium or Iridium-Catalyzed Allylic Substitution of
Guanidines having Electron-Withdrawing Substituents Pp.119-121
Hideto
Miyabe, Akira Matsumura, Kazumasa Yoshida, Masashige Yamauchi and Yoshiji Takemoto
A One-Pot, Rhodium-Catalyzed
Hydrostannylation-Conjugate Addition in Air and Water Pp.122-124
Wei
Wu and Chao-Jun Li
Embedded Mn-Porphyrins in PDMS and ORMOSILs as
Effective Catalysts for Cyclooctene Epoxidation by H2O2
in Supercritical Carbon Dioxide
Pp.125-128
Sandro
Campestrini, Alessandro Donoli and Umberto Tonellato
Enantioselective Catalytic Phase Transfer Michael
Addition of Methyl 4- Cyano-4-(3,4-Dichlorophenyl)Butanoates on Acrylates Pp.129-133
Patrice
Cann, Vincent Levacher, Jean Bourguignon and Georges Dupas
A New Synthesis of
2-[(Dialkylcarbamoyl)Methylene]Tetrahydrofuran Derivatives by Pd-Catalyzed
Oxidative Aminocarbonylation of 4-yn-1-ols Pp.134-136
Bartolo
Gabriele, Giuseppe Salerno and Pierluigi Plastina
Phosphonium Salt Catalyzed Henry Nitroaldol Reactions Pp.137-139
J.
McNulty, J. Dyck, V. Larichev, A. Capretta and A. J. Robertson
Synthesis and Stability of 1-Phenylethenyl Phosphate
Derivatives and their Phosphoryl Transfer Activity Pp.140-144
Tomohisa
Moriguchi, Kazuhisa Okada, Kohji Seio and Mitsuo Sekine
Aminophosphanes as Iminophosphoranyl Synthons:
Efficient P-H Addition to Activated C=C Bonds Pp.145-147
Mateo
Alajarin, Carmen Lopez-Leonardo and Pilar Llamas-Lorente
A New Class of Ferrocenyl Phosphines Pp.148-150
Richard
Stead and Jianliang Xiao
Facile Synthesis of Unsymmetrically Substituted
Ferrocene-1,1’-bis- Carboxamides via Homogeneous Catalytic Carbonylation Pp.151-153
Árpad
Kuik, Zsolt Szarka, Rita Skoda-Foldes and Laszlo Kollar
Synthesis and Cellular Uptake of Fluorescently Labeled
1-Chloromethyl-5- Hydroxy-1, 2-Dihydro-3H-Benz [e] Indole (Seco-CBI)- Pyrrole
Polyamide Conjugates Pp.154-158
Rohtash
Kumar, Dinesh Rai, Sandra L. Marcus, Simon Ching Chun Ko and J.William Lown
Fine-Tuning of Acid Susceptibility of 4,
4’-Dimethoxytrityl Ether Derivatives by a Methoxy Group Introduced via a Styryl
Substituent Pp.159-162
Kohji
Seio, Takahide Sasaki and Mitsuo Sekine
Synthesis and Reactivity of a-Halogenated, C-Protected b-Enamino Acids Pp.163-167
S.
Fustero, E. Salavert, J. F. Sanz-Cervera, R. Roman, B. Fernandez-Gutierrez and
A. Asensio
Simple and Convenient Synthesis of Iboga-Functionalized
Isoquinuclidines Pp.168-170
Enzymatic Oxidation of 1,4- and 1,8-Cineole using Plant
Cultured Cells of Catharanthus Roseus
Pp.171-172
Hiroki
Hamada, Kohji Ishihara, Nobuyoshi Nakajima, Hatsuyuki Hamada, Howard J.
Williams, and Alastair I. Scott
Lipase-Catalyzed Regioselective Acetylations and
Deacetylations of MeOPEG-Bound Xylopyranose Pp.173-175
Carmen
de Torres and Alfonso Fernandez-Mayoralas
Cytotoxic Resibufogenin Transformation Products from
Cell Suspension Cultures of Platycodon Grandiflorum Pp.176-178
Lixin
Li, Ping Li, Min Ye, Lei Zhong and Dean Guo
Synthesis of N-(Trimethylsilylethoxycarbonyl)-deoxycytidine
and Deoxyadenosine Derivatives as Key Intermediates for the DNA Synthesis Using
Fluoride Ion-Promoted Deprotection Strategy Pp.179-182
Mitsuo
Sekine, Masanori Tobe, Takashi Nagayama and Takeshi Wada
Towards Oligonucleotide Pro-Drugs:
2,2-Bis(ethoxycarbonyl) and 2- (Alkylaminocarbonyl)-2-cyano Substituted
3-(Pivaloyloxy)Propyl Groups as Biodegradable Protecting Groups for
Internucleosidic Phosphoromonothioate Linkages Pp.183-188
P. Poijarvi, M. Oivanen and H. Lonnberg
Cyclovibsanins, Unprecedented Seven-Membered
Vibsane-Type Diterpenes from Viburnum awabuki Pp.189-193
Yoshiyasu
Fukuyama, Mai Morisaki, Yuka Minoshima, Hiroyuki Minami, Hironobu Takahashi,
and Yoshinori Asakawa
A Synthetic Route to Cell Permeable, Macrocyclic-Based
Phosphonate Acyloxymethyl Esters
Pp.194-200
Medardo
R. Chavez, Piyu Zhao, Zoltan Kovacs and A. Dean Sherry
Abstracts
[Back to top] Cobalt-Catalyzed Allylation of Aldimines by Allylic
Acetates
Paulo Gomes, Corinne Gosmini and Jacques Perichon
A Barbier-type allylation of aldimines by allylic acetates in the presence of zinc dust and a simple cobalt halide catalyst takes place in acetonitrile to give the corresponding homoallylic amines in good yields.
[Back to top] Nucleophilic Additions of Niobium Enolates of
Oxazolidinones to Aromatic Aldehydes and Aldimines
Carlos
Kleber Z. Andrade, Patricia P. Kalil, Rafael O. Rocha, Luana M. Alves and Curt
M. A. Panisset
Niobium enolate of oxazolidinone 2 was generated by the combination of NbCl5 and a tertiary amine, which then reacted with benzaldehyde and aldimines. The products were obtained in good yields.
[Back to top] Synthesis of p-Conjugated Systems from
Methyldiazines and Aromatic Aldehydes under PTC Conditions and without Organic
Solvent
Laurent
Pascal, Jean Jacques Vanden Eynde, Yves Van Haverbeke and Philippe Dubois
The condensation reactions of 4-methylpyrimidine and methylpyrazine with p-anisaldehyde have been studied in NaOH 5M in the presence of catalytic amount of a quaternary ammonium salt (“quat”). This study seems to give credit to a PTC/OH extraction process where an hydroxide ion would be transferred into the "pseudo organic phase" consisted by liquid reagents. However, an IPTC process cannot be ruled out for some of tested quats.
[Back to top] Palladium or Iridium-Catalyzed Allylic Substitution of
Guanidines having Electron-Withdrawing Substituents
Hideto
Miyabe, Akira Matsumura, Kazumasa Yoshida, Masashige Yamauchi and Yoshiji Takemoto
As a new direct functionalization of guanidines, the N-allylic substitution of guanidines was studied. The nitrogen atom of guanidine derivatives having two N-electron-withdrawing substituents acted as a reactive nucleophile in the allylic substitution.
[Back to top] A One-Pot,
Rhodium-Catalyzed Hydrostannylation-Conjugate Addition in Air and Water
Wei Wu and Chao-Jun Li
A highly efficient and stereoselctive hydrosilylation and hydrostannyla-tion of terminal alkynes was developed in air and water that provided an aqueous one-pot, hydrostannylation/ conjugate addition
[Back to top] Embedded
Mn-Porphyrins in PDMS and ORMOSILs as Effective Catalysts for Cyclooctene
Epoxidation by H2O2 in Supercritical Carbon Dioxide
Sandro Campestrini, Alessandro Donoli and Umberto Tonellato
The heterogeneous oxidation of cyclooctene with H2O2 catalyzed by Mn-porphyrins embedded in polydimethylsiloxane (PDMS) and organically modified silicates (ORMOSILs), in the presence of hexafluoroacetone hydrate (HFAH) as co-catalyst, has been studied in supercritical carbon dioxide (scCO2) at 40oC and 20 MPa. Complete olefin conversion may be obtained with the formation of cyclooctene oxide as sole product, employing molar ratios of Mn-porphyrin/Substrate/H2O2 of 1:400:2000.
[Back to top] Enantioselective
Catalytic Phase Transfer Michael Addition of Methyl 4-
Cyano-4-(3,4-Dichlorophenyl)Butanoates on Acrylates
Patrice Cann, Vincent Levacher, Jean Bourguignon and Georges Dupas
Two routes are examined to achieve the synthesis of a glutarimide possessing a quaternary asymmetric centre with good stereocontrol. It appears that the first one, involving enantioselective Michael addition of cyano-4-(3,4-dichlorophenyl)butanoate on allyl acrylate is the most interesting in terms of cleanness of reactions and stereocontrol. The best system involves a quinidine derived catalyst at – 40°C with potassium hydroxide as a base and gave a medium ee (60%).
[Back to top] A New
Synthesis of 2-[(Dialkylcarbamoyl)Methylene]Tetrahydrofuran Derivatives by
Pd-Catalyzed Oxidative Aminocarbonylation of 4-yn-1-ols
Bartolo Gabriele, Giuseppe Salerno and Pierluigi Plastina
A novel synthesis of 2-[(dialkylcarbamoyl)methylene]tetrahydrofuran derivatives 3-8 by Pd-catalyzed oxidative carbonylation of 4-yn-1-ols 1 in the presence of dialkylamines 2 is reported (2:1 molar ratio = 2). Reactions are carried out in 1,2-dimethoxyethane (DME) at 100 °C and under 20 atm (at 25 °C) of a 4:1 mixture of CO and air, in the presence of catalytic amounts of PdI2 (1 mol % with respect to 1) in conjunction with 10 equiv. of KI. Formation of 3-8 occurs through Pd-catalyzed oxidative monoaminocarbonylation of the triple bond of 1 to give 6-hydroxy-2-ynamide intermediates 9, followed by stereoselective conjugate addition of the hydroxyl group to the triple bond.
[Back to top] Phosphonium
Salt Catalyzed Henry Nitroaldol Reactions
J. McNulty, J. Dyck, V. Larichev, A. Capretta and A. J. Robertson
Trihexyl(tetradecyl)phoshonium decanoate was shown to be an effective promoter for the Henry nitroaldol reaction of nitromethane with aromatic aldehydes. A mechanism is proposed involving Lewis acid activation of the carbonyl group proceeding through a trigonal-bipyramidal intermediate. Evidence in accord with the postulated pathway as opposed to a base or phase transfer-mediated route involving proton transfer from the nitroalkane is presented.
[Back to top] Synthesis
and Stability of 1-Phenylethenyl Phosphate Derivatives and their Phosphoryl
Transfer Activity
Tomohisa Moriguchi, Kazuhisa Okada, Kohji Seio and Mitsuo Sekine
1-Phenylethenyl phosphate derivatives of the monoester type were synthesized via the Perkow reaction. Among them, 2-(2,4-difluorophenyl)ethenyl phosphate was found to be obtained as a pure salt. It turned out that this compound and 2-phenylethenyl phosphate can transfer their phosphoryl groups to AMP in pyridine at elevated temperatures to give ADP.
[Back to top] Aminophosphanes
as Iminophosphoranyl Synthons: Efficient P-H Addition to Activated C=C Bonds
Mateo Alajarin, Carmen Lopez-Leonardo and Pilar Llamas-Lorente
Asymmetrically substituted bis(iminophosphoranes) derived from 1,2-bis(diphenylphosphino)ethane are prepared by Michael-type addition of easily available N,P,P-trisubstituted aminophosphanes to P-vinyl iminophosphoranes. Similarly P-alkylations of aminophosphanes with P-vinyl phosphane oxides and sulfides are also disclosed.
[Back to top] A New
Class of Ferrocenyl Phosphines
Richard Stead and Jianliang Xiao
A new series of ferrocenyl diphosphines have been synthesized by Suzuki coupling of diboronic acid of ferrocene with bromo-substituted triphenylphosphine oxides, followed by reduction with HSiCl3.
[Back to top] Facile
Synthesis of Unsymmetrically Substituted Ferrocene-1,1’-bis-
Carboxamides via Homogeneous Catalytic Carbonylation
Árpad Kuik, Zsolt Szarka, Rita Skoda-Foldes and Laszlo Kollar
The synthesis of unsymmetrical ferrocene 1,1’-diamides via homogeneous catalytic aminocarbonylation of 1,1’-diiodo-ferrocene is described. The products were obtained in good yields in a one-pot reaction by using two different secondary amines as nucleophiles simultaneously.
[Back to top] Synthesis
and Cellular Uptake of Fluorescently Labeled 1-Chloromethyl-5- Hydroxy-1,
2-Dihydro-3H-Benz [e] Indole (Seco-CBI)- Pyrrole Polyamide Conjugates
Rohtash
Kumar, Dinesh Rai, Sandra L. Marcus, Simon Ching Chun Ko and J.William Lown
The synthesis is described of 1-chloromethyl-5-hydroxy-1, 2-dihydro-3H-benz [e] indole (seco- CBI)- pyrrole polyamide conjugates (1-4) which were labeled with a fluorescent Fmoc moiety to evaluate their cellular uptake. Confocal laser scanning microscopy (CLSM) indicates that these DNA minor groove-binding agents localize in the cytoplasm and organelles.
[Back to top] Fine-Tuning
of Acid Susceptibility of 4, 4’-Dimethoxytrityl Ether Derivatives by a Methoxy
Group Introduced via a Styryl Substituent
Kohji
Seio, Takahide Sasaki and Mitsuo Sekine
To overcome the problem of depurination in oligoDNA synthesis, we tried to fine-tune the acid lability of the DMTr group by adding a substituted styryl group on the phenyl ring. The styryl groups could buffer the electron donating nature of the methoxy group and enabled the fine-tuning of the acid lability.
[Back to top] Synthesis
and Reactivity of a-Halogenated,
C-Protected b-Enamino
Acids
S.
Fustero, E. Salavert, J. F. Sanz-Cervera, R. Roman, B. Fernandez-Gutierrez and A.
Asensio
C-Protected b-enamino acids (I) reacted with one equivalent of N-halosuccinimides (NXS) to furnish their a-halogenated derivatives (II). These compounds were then successfully transformed into halogenated uracil derivatives (III) through reaction with triphosgene, followed by 5-membered ring-opening under acidic conditions.
[Back to top] Simple and
Convenient Synthesis of Iboga-Functionalized Isoquinuclidines
A.
A. Maia, R. P. Freitas-Gil, L.F. Gil and C. Marazano
Synthesis of Iboga-functionalized isoquinuclidine ring system and alkylated derivatives from commercially available 3-ethyl-pyridine, is reported. The key-step for isoquinuclidine synthesis is a cycloaddition between methyl acrylate and N-benzyl-3-ethyl-5,6-dihydropyridine obtained in situ from N-benzyl-3-ethyl-4-methoxy-1,4,5,6-tetrahydropyridine. Further treatment of isoquinuclidine lithium enolate with appropriate electrophiles gave alkylated products with good stereoselectivity.
[Back to top] Enzymatic
Oxidation of 1,4- and 1,8-Cineole using Plant Cultured Cells of Catharanthus
Roseus
Hiroki Hamada, Kohji Ishihara, Nobuyoshi Nakajima, Hatsuyuki Hamada, Howard J. Williams, and Alastair I. Scott
Oxidases present in plant cultured cells of Catharanthus roseus can hydroxylate saturated centers of natural products without double bond activation. When starting materials were 1,8- or 1,4-cineole, secondary and tertiary alcohols were produced and identified using NMR and mass spectroscopy. Our results indicate that hydroxylation position and stereochemistry are determined by the biotransformation organism.
[Back to top] Lipase-Catalyzed
Regioselective Acetylations and Deacetylations of MeOPEG-Bound Xylopyranose
Carmen de Torres and Alfonso Fernandez-Mayoralas
The regioselectivity of the acetylation of D-xylopyranosides attached to polyethylene glycol monomethyl ether (MeOPEG) catalyzed by lipases from Pseudomonas cepacia and Candida antartica in organic solvent was examined. Partially acetylated derivatives can be obtained with high regioselectivity by acetylation or deacetylation in the presence of the appropriate lipase.
[Back to top] Cytotoxic
Resibufogenin Transformation Products from Cell Suspension Cultures of
Platycodon Grandiflorum
Lixin Li, Ping Li, Min Ye, Lei Zhong and Dean Guo
Four biotransformed products of resibufogenin were obtained after 4 days of incubation with cell suspension cultures of Platycodon grandiflorum. On the basis of chemical and spectral data, their structures were elucidated as 3-epi-resibufogenin, marinobufagin, 1b-hydroxy-resibufogenin, and 3-epi-marinobufagin respectively, among which the latter two compounds are new. These compounds were found to exhibit potent cytotoxic activities against Bel-7402, BGC-823, HeLa, and HL-60 human cancer cell lines.
[Back to top] Synthesis
of N-(Trimethylsilylethoxycarbonyl)-deoxycytidine and Deoxyadenosine Derivatives
as Key Intermediates for the DNA Synthesis Using Fluoride Ion-Promoted
Deprotection Strategy
Mitsuo Sekine, Masanori Tobe, Takashi Nagayama and Takeshi Wada
An improved method for the synthesis of trimethylsilylethyl chloroformate (Teoc-Cl) was studied in great detail. N-Teoc-adenosine, N-Teoc-cytidine and their deoxyribonucleoside derivatives were synthesized as the key synthetic intermediates for the synthesis of base-sensitive oligonucleotide derivatives by use of N-methylimidazole. The stability and chemical properties of these N-protected nucleoside derivatives were examined.
[Back to top] Towards
Oligonucleotide Pro-Drugs: 2,2-Bis(ethoxycarbonyl) and 2-
(Alkylaminocarbonyl)-2-cyano Substituted 3-(Pivaloyloxy)Propyl Groups as
Biodegradable Protecting Groups for Internucleosidic Phosphoromonothioate
Linkages
P. Poijarvi, M. Oivanen and H. Lonnberg
The applicability of 2,2-bis(ethoxycarbonyl)-3-(pivaloyloxy)propyl and 2-cyano-2-(2-phenylethylaminocarbonyl)-3-(pivaloyloxy)propyl groups as biodegrad-able protecting agents for the internucleosidic linkages of phosphorothioate antisense oligonucleotides has been studied. For this purpose, protected phosphoromonothioates of thymidylyl-(3’®5’)-thymidine [Tp(s)T] containing either a bridged or non-bridged sulfur atom have been prepared, and their chemical stability and enzymatic deprotection have been studied.
[Back to top] Cyclovibsanins,
Unprecedented Seven-Membered Vibsane-Type Diterpenes from Viburnum awabuki
Yoshiyasu Fukuyama, Mai Morisaki, Yuka Minoshima, Hiroyuki Minami, Hironobu Takahashi, and Yoshinori Asakawa
Four unprecedented vibsane-type diterpenes, named cyclovibsanin A, 15-O-methylcyclovibsanin A, 15-O-methylcyclovibsanin B, and 3-hydroxy-15-O-methyl-cyclovibsanin A, were isolated from the leaves of Viburnum awabuki. Their unique tricyclo[6.3.2.00,0]tridecane structures and plausible biosynthesis of cyclovibsanins are discussed here.
[Back to top] A
Synthetic Route to Cell Permeable, Macrocyclic-Based Phosphonate Acyloxymethyl
Esters
Medardo R. Chavez, Piyu Zhao, Zoltan Kovacs and A. Dean Sherry
Four cell membrane-permeant derivatives of polyaza macrocyclic ligands, including acetoxymethyl (AM) and pivaloyloxymethyl (POM) esters of 1,4,7,10-tetra-azacyclododecane-1,4,7,10-tetrakis(ethyl methylenephosphonate) (DOTPME) and 1,4,7-triazacyclononane-1,4,7-tris(ethyl methylenephosphonate) (NOTPME), were prepared as model systems for the detection of intracellular ions by 31P NMR spectroscopy. Preliminary results on isolated perfused rat hearts suggest that such ligands may be useful for monitoring intracellular levels of Ca2+ and Mg2+.