Letters in Organic Chemistry, Volume 2, No. 3, 2005
Contents
Short Peptides and Peptide-Like Enzyme Mimics - Efficient Organic Catalysts in Asymmetric Synthesis Pp.208-213
Svetlana
B. Tsogoeva
Letters in Organic Chemistry
Diethylzinc-Mediated Allylation of Natural Biphenyls by
p-1,1-Dimethyleneallylpalladium
Complexes Pp.214-218
Maria
Antonietta Dettori, Jean Ollivier, Pier Paolo Piras, Davide Fabbri, Giovanna
Delogu and Jacques Salaun
Synthesis of Ferrocenylbenzenes via Cp*RuCl-Catalyzed
Partially Intramolecular Cyclotrimerization of Ferrocenylalkynes Pp.219-221
Yoshihiko
Yamamoto, Hisashi Kataoka, Keisuke Kinpara, Hisao Nishiyama and Kenji Itoh
Development of Organoiron Methodology for the C8-C16
Dienylamine Segment of the Streptogramin Antibiotics Pp.222-225
Fahim
Ahmed, Yeyu Cao and William A. Donaldson
Cycloaddition of Nitrones and Nitrile Oxides to
Activated Exo-glycals Pp.226-230
C.
Taillefumier, G. Enderlin and Y. Chapleur
Regioselective Synthesis of
3-(aryloxyacetyl)-2,3-dihydrothieno[3,2-c][1] benzothiopyran-4-ones: A
Tandem [2,3] and [3,3]sigmatropic Rearrangement Approach Pp.231-234
K.C.
Majumdar, S.K. Chattopadhyay and M. Ghosh
Mannich-type Reaction of Methylene Active Compounds
with a Chiral Sulfinimine of Trifluoropyruvate: New Highly Stereoselective
Synthesis of (S)-a-Trifluoromethyl-Aspartic
Acid Pp.235-237
Francesco
Lazzaro, Arnaud Gissot, Marcello Crucianelli, Francesco De Angelis, Luca Bruche
and Matteo Zanda
Stereospecific Synthesis of Chiral
Tetrahydroquinoxaline, 2,3- Dihydrobenzo[ 1,4]dioxin and
2,3-Dihydro-naphtho[2,3-b][1,4]-dioxin Derivatives Pp.238-241
Raid
J. Abdel-Jalil, Syed Tasadaque Ali Shah, Khalid Mohammed Khan and Wolfgang
Voelter
Sc(OTf)3 Efficiently Catalyzed the
Glycosidation of 1-C-Alkyl-2,3,4,6-tetra-O-benzyl-a-D-glucopyranosyl Acetates with Alcohols Pp.242-246
Takashi
Yamanoi, Yoshiki Oda, Ippo Yamazaki, Masae Shinbara, Kenji Morimoto and Sho
Matsuda
Structure/Activity Relationship of Carba- and
C-Fucopyranosides as Inhibitors of an a
1,6-Fucosyltransferase by Molecular Modeling and Kinetic Studies Pp.247-251
Felix
Calderon, Mercedes Carpintero, Eduardo Garcia-Junceda, Alfonso
Fernandez-Mayoralas and Agatha Bastida
Synthesis of p-tert-Butyl-5,5'-bicalix[4]arene
and Access to 5,5'-Bicalix[4] arenes Functionalized at the Upper Rim Pp.252-257
Grazia
M.L. Consoli, Francesca Cunsolo, Corrada Geraci and Placido Neri
Occurrence of Long-Chain-Alkanes and Polycyclic
Aromatic Hydrocarbons (PAHs) in the Thermal System of Carbonate and Sodium Pp.258-260
Qiang
Wang, Fangyu Cao and Qianwang Chen
Degraded Terpenoids and Aromatic Compounds from
Ternstroemia Gymnanthera Pp.262-264
Motoo
Tori, Hiroko Fukuyama, Katsuyuki Nakashima and Masakazu Sono
Some Observations on the Preparation of Amides and
their Reduction to Amines in Ionic Liquids Pp.265-270
Lucia
Raffaella Lampariello, Daniela Peruzzi, Alessandro Sega and Maurizio Taddei
2-Benzothiazolyl 1-Thiofuranosides - Synthesis and
Application Pp.271-273
J.
Bogusiak
Synthesis of a Dicarba-Analog of Octreotide Keeping the
Type II’ b-Turn of the
Pharmacophore in Water Solution Pp.274-279
Alfonso
Carotenuto, Debora D’Addona, Eleonora Rivalta, Mario Chelli, Anna Maria Papini,
Paolo Rovero and Mauro Ginanneschi
Synthesis of b-Ketonitriles
from 3-Bromoisoxazoles Pp.280-282
Abstracts
[Back to top] Short Peptides and Peptide-Like Enzyme Mimics -
Efficient Organic Catalysts in Asymmetric Synthesis
Svetlana
B. Tsogoeva
The development of peptide-based enzyme mimics as organic catalysts for enantioselective synthesis is of rapidly growing interest today. In the following a brief overview about advantages of oligopeptide catalysts and recent achievements in peptide-catalyzed asymmetric synthesis, published in 2004, is given.
[Back to top] Diethylzinc-Mediated Allylation of Natural Biphenyls by p-1,1-Dimethyleneallylpalladium
Complexes
Maria
Antonietta Dettori, Jean Ollivier, Pier Paolo Piras, Davide Fabbri, Giovanna
Delogu and Jacques Salaun
1-Ethenylcyclopropyl sulfonate underwent electrophilic g- and a-substitutions by the carbonyls of naturally occurring biphenyls derived from vanillin and acetovanillone, in the presence of palladium(0) and diethylzinc, to provide regioisomeric 5,5’-di(3-cyclopropylidene-1-hydroxypropyl) biphenyls and 5,5’-di[1-(1-ethenylcyclopropyl)-1-hydroxymethyl]biphenyls of biological interest.
[Back to top] Synthesis of Ferrocenylbenzenes via
Cp*RuCl-Catalyzed Partially Intramolecular Cyclotrimerization of
Ferrocenylalkynes
Yoshihiko
Yamamoto, Hisashi Kataoka, Keisuke Kinpara, Hisao Nishiyama and Kenji Itoh
In the presence of catalytic amounts of Cp*RuCl(cod), the [2 + 2 + 2] cycloaddition of 1,6-diynes with ethynylferrocene proceeded at ambient temperature to afford ferrocenylbenzenes in 62-72% yields. An unsymmetrical 1,6-diyne bearing a ferrocenyl terminal was allowed to react with monoalkynes to give the corresponding meta-substituted cycloadducts selectively as single regioisomers. On the other hand, Bis(ferrocenyl)ruthenacyclopentatriene was formed from a diyne bearing a ferrocenyl group on both terminals and excess Cp*RuCl(cod).
[Back to top] Development of Organoiron Methodology for the C8-C16
Dienylamine Segment of the Streptogramin Antibiotics
Fahim
Ahmed, Yeyu Cao and William A. Donaldson
Methodology for preparation of the C8-C16 dienylamine segment of the streptogramin antibiotics is based on a diastereoselective nitrile oxide-olefin cycloaddition to a (triene)iron complex. The Fe(CO)3 adjunct also serves as a protecting group for the subsequent reductive hydrolysis of the isoxazoline ring.
[Back to top] Cycloaddition of Nitrones and Nitrile Oxides to Activated Exo-glycals
C.
Taillefumier, G. Enderlin and Y. Chapleur
The 3+2 cycloaddition reaction of nitrones and nitrile oxides with activated exo-glycals obtained from the Wittig reaction of sugar lactones gave good yields of only two cycloadducts. The reaction was efficiently carried out under microwave activation.
[Back to top] Regioselective Synthesis of
3-(aryloxyacetyl)-2,3-dihydrothieno[3,2-c][1] benzothiopyran-4-ones: A
Tandem [2,3] and [3,3]sigmatropic Rearrangement Approach
K.C.
Majumdar, S.K. Chattopadhyay and M. Ghosh
Hitherto unreported 3-(aryloxyacetyl)-2,3-dihydrothieno[3,2-c][1]benzothiopyran-4-ones (4a-f) were synthesized in excellent yield by the application of the tandem [2,3] and [3,3] sigmatropic rearrangements of the 4-(4/-aryloxybut–2/-ynylthio)[1]benzothiopyran-2-ones (3a-f). The substrates (3a-f) were synthesized by phase transfer catalyzed alkylation of previously unreported 4-mercaptothiopyran-2-ones with different 1-aryloxy-4-chlorobut-2-ynes.
[Back to top] Mannich-type Reaction of Methylene Active Compounds with a
Chiral Sulfinimine of Trifluoropyruvate: New Highly Stereoselective Synthesis
of (S)-a-Trifluoromethyl-Aspartic
Acid
Francesco
Lazzaro, Arnaud Gissot, Marcello Crucianelli, Francesco De Angelis, Luca Bruche
and Matteo Zanda
A strongly improved, highly stereoselective synthesis of (S)-a-trifluoromethyl aspartic acid via addition of lithium malonate to a chiral sulfinimine of trifluoropyruvate is presented.
[Back to top] Stereospecific Synthesis of Chiral Tetrahydroquinoxaline,
2,3- Dihydrobenzo[ 1,4]dioxin and 2,3-Dihydro-naphtho[2,3-b][1,4]-dioxin
Derivatives
Raid
J. Abdel-Jalil, Syed Tasadaque Ali Shah, Khalid Mohammed Khan and Wolfgang
Voelter
In this communication a convenient and novel method for the stereospecific synthesis of chiral tetrahydroquinoxaline, 2,3-dihydro-benzo[1,4]dioxin and 2,3-dihydro-naphtho[2,3-b][1,4]dioxin derivatives from anhydro sugars is described.
[Back to top] Sc(OTf)3 Efficiently Catalyzed the
Glycosidation of 1-C-Alkyl-2,3,4,6-tetra-O-benzyl-a-D-glucopyranosyl Acetates with Alcohols
Takashi
Yamanoi, Yoshiki Oda, Ippo Yamazaki, Masae Shinbara, Kenji Morimoto and Sho
Matsuda
Several 1-C-alkyl-2,3,4,6-tetra-O-benzyl-a-D-glucopyranosides were stereoselectively synthesized in good yields by the reaction of the 1-C-alkyl-2,3,4,6-tetra-O-benzyl- a-D-glucopyranosyl acetates with alcohols in the presence of 5 mol% Sc(OTf)3. The nature of the alkyl groups at the anomeric centers of the glycosyl donors had almost no influence on the reactivity and stereoselectivity of this glycosidation.
[Back to top] Structure/Activity Relationship of Carba- and
C-Fucopyranosides as Inhibitors of an a
1,6-Fucosyltransferase by Molecular Modeling and Kinetic Studies
Felix
Calderon, Mercedes Carpintero, Eduardo Garcia-Junceda, Alfonso Fernandez-Mayoralas
and Agatha Bastida
Several carba- and C-fucopyranosides have been tested as inhibitors of recombinant a 1,6-Fucosyltransferase from Rhizobium sp. 1-(R)-amino-phenylmethyl C-fucopyranoside (7) with 4C1(L) conformation showed the highest inhibition (IC50 = 690 µM). Molecular modeling alloweded us to establish an structure/activity relationship for the carba- and C-fucopyranosides inhibition activity.
[Back to top] Synthesis of p-tert-Butyl-5,5'-bicalix[4]arene and
Access to 5,5'-Bicalix[4] arenes Functionalized at the Upper Rim
Grazia
M.L. Consoli, Francesca Cunsolo, Corrada Geraci and Placido Neri
Compound 1, a double p-tert-butylcalix[4]arene with direct para-para linkage, was obtained by FeCl3- mediated oxidative coupling of 5,11,17-tri-p-tert-butyl-26,27,28-tribenzoyloxycalix[4]arene-25-ol (4) followed by alkaline hydrolysis. With respect to the de-tert-butylated counterpart 1a, a different reactivity of 1 was observed in the NaH-promoted propylation, which gave octapropyl double-cone atropisomer 6 with higher stereoselectivity. Under competitive conditions 6 was selectively mononitrated at the biphenyl system, whereas ipso-nitration at t-Bubearing rings was obtained using a larger excess of HNO3.
[Back to top] Occurrence of Long-Chain-Alkanes and Polycyclic Aromatic
Hydrocarbons (PAHs) in the Thermal System of Carbonate and Sodium
Qiang
Wang, Fangyu Cao and Qianwang Chen
Multi-carbon bearing hydrocarbon molecules such as PAHs and long-chain-alkanes were obtained in the reaction of dolomite with metallic sodium. Fischer-Tropsch synthesis under the condition of supercritical carbon dioxide was proposed for the formation of PAHs and long-chain-alkanes. This result might be helpful to understand the formation mechanism of diamond and other carbon-based materials in CO2-alkali metal systems in our previous results.
[Back to top] Degraded Terpenoids and Aromatic Compounds from Ternstroemia
Gymnanthera
Motoo
Tori, Hiroko Fukuyama, Katsuyuki Nakashima and Masakazu Sono
Two new degraded terpenoids and an aromatic compound, as well as kaurene, methyl p-tolylbenzoate, methyl 4-hydroxy-2-hydroxymethylbenzoate, and 1-(2,6,6-trimethyl-4-oxo-2-cyclohexenyl)- 2(E)-buten-1-one, were isolated from Ternstroemia gymnanthera.
[Back to top] Some Observations on the Preparation of Amides and their
Reduction to Amines in Ionic Liquids
Lucia
Raffaella Lampariello, Daniela Peruzzi, Alessandro Sega and Maurizio Taddei
The preparation of amides in ionic liquids was explored using the Schotten-Baumann procedure, the Weinreb amidation of esters and the classical coupling reaction using EDC, HBTU or DMTMM as the coupling agents. In any case amides were obtained in comparable or better yields and with a simplified procedure than using conventional solvents. Moreover, the amides were directly reduced in the same flask to the corresponding secondary or tertiary amines by heating in the presence of solid sodium borohydride.
[Back to top] 2-Benzothiazolyl 1-Thiofuranosides - Synthesis and
Application
J.
Bogusiak
2-Benzothiazolyl 1-thiofuranosides derivatives of L-arabino-, D-ribo- and D-xylofuranose were synthesized in good yield in a one-pot reaction by treatment of reducing monosaccharides with diphenyl phosphorochloridate and 2-mercaptobenzothiazol under phase-transfer conditions. Their ability to act as glycosyl donors was demonstrated.
[Back to top] Synthesis of a Dicarba-Analog of Octreotide Keeping the
Type II’ b-Turn of the
Pharmacophore in Water Solution
Alfonso
Carotenuto, Debora D’Addona, Eleonora Rivalta, Mario Chelli, Anna Maria Papini,
Paolo Rovero and Mauro Ginanneschi
The Z isomer of the new constrained analog of the anticancer drug octreotide, where L,L-cystine is replaced by 4,5-dehydro-L,L-diaminosuberic acid, was prepared by solid-phase ring-closing metathesis. NMR study ascertained that this molecule is conformationally very close to the parent octreotide and remains unaffected by the enzymatic pool of the human serum for more than 30 h.
[Back to top] Synthesis of b-Ketonitriles
from 3-Bromoisoxazoles
Martin
G. Kociolek, Nicholas G. Straub and Elizabeth J. Marton
A series of substituted 3-bromoisoxazoles were ring opened with either molybdenum hexacarbonyl or iron (II) chloride tetrahydrate to give b-ketonitriles in good yields.