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Letters in Organic Chemistry
ISSN: 1570-1786
Letters in Organic Chemistry
Volume 6, Number 3, April 2009
Contents
Concise Synthesis of Non-Protein Amino Acid from Natural Product
via Schmidt Reaction Pp. 186-188
Kamila Gajcy, Tadeusz Librowski and
Stanislaw Lochynski
[Abstract] [Purchase
Article]
Synthesis of 4,5-Dimethoxy-o-benzoquinone
by Formal [4+2] Cyclization of 2,3-Dimethoxy-1,3-butadiene
with Oxalyl Chloride Pp. 189-190
Gerson Mroβ
and Peter Langer
[Abstract] [Purchase
Article]
A Method for the Syntheses of Enopyranosides Pp.
191-196
Khalid M. Khan, Shahnaz Perveen, Raed A.
S. Al-Qawasmeh, Mohammed S. Shekhani, Syed T. Ali Shah and
Wolfgang Voelter
[Abstract] [Purchase
Article]
The Practical Synthesis of Double Axial Chiral Guanidines
Pp. 197-202
Qun-Sheng Guo and Da-Ming Du
[Abstract] [Purchase
Article]
Synthesis of Substituted Imidazo[1,5-a]pyrimidines,
1H pyrrolo[2,3-b] pyridines and 3-methyl-3H-imidazo[4,5-b]pyridines
Pp. 203-207
Jingshing Wu, Xuechao Xing and
Gregory D. Cuny
[Abstract] [Purchase
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Solvent-Free Microwave-Assisted Synthesis of New 2-Aryl-
Tetrahydro-quinolines Using Three-Component Povarov Reaction
Pp. 208-212
Luis S. Astudillo, Margarita Gutiérrez C., Hugo Gaete,
Vladimir V. Kouznetsov, Carlos M. Meléndez, J. Antonio
Palenzuela and Gabriel Vallejos G.
[Abstract] [Purchase
Article]
Synthesis of New 1, 4-Dihydropyridines by Addition
Rearrangement Process with Imine Derivatives and β-Ketoester
as Starting Materials in Solvent-Free Conditions Pp.
213-218
Xueming Chen, Xiaoguang Huang, Yunyun Chen,
Feng He and Xingshu Li
[Abstract] [Supplementary
Material] [Purchase
Article]
Synthesis and Luminescence of 7-amino-2H-indazolo[2,1-b]
phthalazine-1,6,11(13H)-triones Catalyzed by Silica
Sulfuric Acid Pp. 219-223
Hui Wu, Xiu-Mei Chen, Yu Wan, Hai-Qiang
Xin, Hua-Hong Xu, Rui Ma, Cai-Hui Yue and Li-Ling
Pang
[Abstract] [Purchase
Article]
Allyl Silane Additions to Highly Electrophilic 5,6-Dihydro-2H-1,
4-oxazinones Pp. 224-228
Cynthia M. Shafer, Julie Pigza and
Tadeusz F. Molinski
[Abstract] [Purchase
Article]
Application of Lanthanoid Catalysts for the Synthesis
of Michler's Hydride Pp. 229-233
Philip C. Andrews, Peter C. Junk, K. Peter Kemppinen,
Kristina Konstas and Kellie L. Tuck
[Abstract] [Purchase
Article]
HClO4-SiO2
and NaHSO4-SiO2:
Two Efficient Heterogeneous Catalysts for Synthesis of N-Acylsulfonamides
under Solvent-free Conditions Pp. 234-236
Liqiang Wu, Chunguang Yang, Chong Zhang
and Liming Yang
[Abstract] [Purchase
Article]
Reversible Friedel-Crafts Acylations of Anthracene:
Rearrangements of Acetylanthracenes Pp.
237-241
Tahani Mala'bi, Sergey Pogodin and
Israel Agranat
[Abstract] [Purchase
Article]
Preparation of Disubstituted Phenyl Propargyl Alcohols,
their Use in Oxathiolene Oxide Synthesis, and Evaluation of
the Oxathiolene Oxide Products as Anticarcinogenic Enzyme
Inducers Pp. 242-251
Maben Ying, Matthew G. Smentek, Rong Ma,
Cynthia S. Day, Suzy V. Torti and Mark E. Welker
[Abstract] [Full
Text Article]
Preparation and Structures of Isoindolone- or Pyrimidone
Condensed Hetero-Cycles Containing a Hydroxy Group on a Cyclohexane
or Norbornane Moiety Pp. 252-257
Ferenc Miklós, Pál Sohár,
Antal Csámpai, Reijo Sillanpää and Géza
Stájer
[Abstract] [Purchase
Article]
Chiral Recognition of 2-Hydroxypropyl-alpha-cyclodextrin
Towards DL-Tryptophan Pp. 258-263
Luiz Fernando B. Malta, Jaqueline D. Senra,
Luzineide W. Tinoco, M.E. Medeiros and Octavio A.C.
Antunes
[Abstract] [Purchase
Article]
α-Pinene-Based
New Chiral Ionic Liquids and their Application as Phase Transfer
Catalysts in Enantioselective Addition of Diethylzinc to Aldehydes
Pp. 264-268
Sanjay V. Malhotra, Yun Wang and Vineet
Kumar
[Abstract] [Purchase
Article]
Abstracts
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Article]
Concise Synthesis of Non-Protein Amino Acid from Natural Product
via Schmidt Reaction
Kamila Gajcy, Tadeusz Librowski and
Stanislaw Lochynski
In this work we aimed at finding a concise method for
the design of the new pharmacologically active compound 6,
which is a precursor to obtaining non-protein amino acid 7
considered as GABA analogue, furthermore it can be used to
construct enantiopure, conformationally restricted peptides.
For this purpose the Schmidt reaction was applied.
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Synthesis of 4,5-Dimethoxy-o-benzoquinone by Formal
[4+2] Cyclization of 2,3-Dimethoxy-1,3-butadiene with Oxalyl
Chloride
Gerson Mroβ
and Peter Langer
The cyclization of 2,3-dimethoxy-1,3-butadiene with oxalyl
chloride provides a new method for the synthesis of 4,5 dimethoxy-o-benzoquinone.
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Article]
A Method for the Syntheses of Enopyranosides
Khalid M. Khan, Shahnaz Perveen, Raed A.
S. Al-Qawasmeh, Mohammed S. Shekhani, Syed T. Ali Shah and
Wolfgang Voelter
Sodium hydride (NaH) in hexamethylphosphoric triamide
(HMPA) has been introduced as an economical and efficient
reagent towards the creation of 1,2- or 5,6-enopyranosides
from the corresponding halogenated or tosylated pyranosides.
NaH/HMPA has several advantages compared to NaH/DMF:
elimination products are produced in high yields even from
sterically-hindered halides as well as tosylates.
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The Practical Synthesis of Double Axial Chiral Guanidines
Qun-Sheng Guo and Da-Ming Du
Two novel double axial chiral guanidines were designed
according to the concept of double axial chirality. The practical
synthetic procedures from (S)-1,1’-binaphthol
have been developed. The title compounds were fully characterized
by NMR, MS, IR and elemental analysis or HRMS. The two chiral
guanidines can be interesting catalysts for asymmetric catalysis
and preliminary asymmetric catalytic activity was investigated
in Henry reaction and conjugate addition.
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Synthesis of Substituted Imidazo[1,5-a]pyrimidines, 1H pyrrolo[2,3-b]
pyridines and 3-methyl-3H-imidazo[4,5-b]pyridines
Jingshing Wu, Xuechao Xing and
Gregory D. Cuny
Cyclization of in situ generated 5-aminoimidazoles
with various malondialdehydes or 1,3-diketones gave substituted
imidazo[1,5-a]pyrimidines. However, cyclization of 2-aminopyrroles
and 5-amino-1-methylimidazoles resulted in condensations on
a carbon atom of the heterocyclic ring instead of nitrogen
generating 1H-pyrrolo[2,3-b]pyridines (i.e. 7-azaindoles)
and 3-methyl-3H-imidazo[4,5-b]pyridines, respectively. In
these cases the addition of pyrrolidine to the reaction mixture
after the initial condensation between the amino group and
one of the carbonyl groups of the malondialdehydes or 1,3-diketones
significantly increased the yields of 1H-pyrrolo[2,3-b]pyridines
and 3-methyl-3H-imidazo[4,5-b]pyridines.
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Solvent-Free Microwave-Assisted Synthesis of New 2-Aryl- Tetrahydro-quinolines
Using Three-Component Povarov Reaction
Luis S. Astudillo, Margarita Gutiérrez
C., Hugo Gaete, Vladimir V. Kouznetsov, Carlos M. Meléndez,
J. Antonio Palenzuela and Gabriel Vallejos G.
A new series of 2-aryl-1,2,3,4-tetrahydroquinolines has
been synthesized in good yields through a BiCl3-catalyzed
three-component Povarov reaction (imino Diels-Alder cycloaddition)
between anilines, benzaldehydes and N-vinylpyrrolidin-2-one
in MeCN. The same series has been prepared without solvent
using microwave radiation, which resulted in better yields,
a considerable decrease in reaction times and simplified workup.
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Synthesis of New 1, 4-Dihydropyridines by Addition Rearrangement
Process with Imine Derivatives and β-Ketoester
as Starting Materials in Solvent-Free Conditions
Xueming Chen, Xiaoguang Huang, Yunyun Chen,
Feng He and Xingshu Li
[Supplementary
Material]
N-substituted 1,4-dihydropyridines bearing a carboxyl
group at the 4-position were synthesized in solvent-free conditions
with Cu2+ as the catalyst,
imine and β-ketoester
as starting materials. The possible mechanism which consists
of addition-rearrangement process was proposed and examined
by the reaction of isolated product of first addition to β-ketoester.
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Synthesis and Luminescence of 7-amino-2H-indazolo[2,1-b]
phthalazine-1,6,11(13H)-triones Catalyzed by Silica
Sulfuric Acid
Hui Wu, Xiu-Mei Chen, Yu Wan, Hai-Qiang
Xin, Hua-Hong Xu, Rui Ma, Cai-Hui Yue and Li-Ling
Pang
7-amino-2H-indazolo[2,1-b]phthalazine-1,6,11(13H)-triones
were synthesized via the three-component condensation
of luminol, dimedone, and aromatic aldehydes in EtOH at 80
ºC
for 9-15 min catalyzed by solid silica sulfuric acid (SSA)
and the luminescence of products was studied in details.
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Article]
Allyl Silane Additions to Highly Electrophilic 5,6-Dihydro-2H-1,
4 oxazinones
Cynthia M. Shafer, Julie Pigza and
Tadeusz F. Molinski
Allylsilane addition to the dihydro-2H-1,4-oxazinones,
1, proceeded in moderate to good yields with
trans-diastereoselectivity. The yield of addition
reactions of 5-phenyl-5,6-dihydro-2H-1,4-oxazin-2-one
with allylsilanes is improved over the corresponding additions
of Grignard reagents to 1 and illustrates
a simple path to protected β,β-disubstituted
α-amino
acids.
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Application of Lanthanoid Catalysts for the Synthesis of Michler's
Hydride
Philip C. Andrews, Peter C. Junk, K. Peter Kemppinen,
Kristina Konstas and Kellie L. Tuck
A series of lanthanoid (Ln3+)
based Lewis acid catalysts were investigated as alternatives
to other metal based catalysts for the formation of Michler's
hydride, 4,4'-methylenebis(N,N-dimethylaniline) (1).
The lanthanoid based Lewis acid catalysts were superior to
previously published catalysts resulting in formation of 4,4'-methylenebis(N,N-dimethylaniline)
(1) and N,N-dimethyl-4-(4-(methylamino)benzyl)aniline
(2). If paraformaldehyde was added to the
reaction only 4,4'-methylenebis(N,N-dimethylaniline)
(1) was formed.
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HClO4-SiO2
and NaHSO4-SiO2:
Two Efficient Heterogeneous Catalysts for Synthesis of N-Acylsulfonamides
under Solvent-free Conditions
Liqiang Wu, Chunguang Yang, Chong Zhang
and Liming Yang
A simple and efficient synthesis of N-acylsulfonamides
has been accomplished by the reaction of sulfonamides with
anhydrides under solvent-free conditions in the presence of
HClO4-SiO2
or NaHSO4-SiO2.
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Reversible Friedel-Crafts Acylations of Anthracene: Rearrangements
of Acetylanthracenes
Tahani Mala'bi, Sergey Pogodin and
Israel Agranat
Treatment of 1-acetylanthracene (1-AcAN) and 9-acetylanthracene
(9-AcAN) with PPA at 80-120 ºC
leads to the nearly complete conversion of these isomers into
2-acetylanthracene (2-AcAN), an illustration of the Agranat-Gore
rearrangement of polycyclic aromatic ketones (PAKs). Ab
initio MP2/6-31(d) calculations predict the following
order of stabilities: for σ-complexes:
9-AcAN>1-AcAN>2-AcAN;
for ketones: 2-AcAN>1-AcAN>9-AcAN;
for O-protonated ketones: 2-AcAN>1-AcAN>9-AcAN.
Thus, 9-AcAN is the kinetically controlled product, whereas
2-AcAN is the thermodynamically controlled product. No reverse
rearrangements of 2-AcAN to either 9-AcAN or 1-AcAN and of
1-AcAN to 9-AcAN were observed. The results strengthen the
pattern of reversibility in Friedel-Crafts acylations of PAHs.
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[Full
Text Article]
Preparation of Disubstituted Phenyl Propargyl Alcohols, their
Use in Oxathiolene Oxide Synthesis, and Evaluation of the
Oxathiolene Oxide Products as Anticarcinogenic Enzyme Inducers
Maben Ying, Matthew G. Smentek, Rong Ma,
Cynthia S. Day, Suzy V. Torti and Mark E. Welker
A number of alkynols have been prepared by Sonogoshira
coupling of propargyl alcohol to disubstituted aromatic halides.
Chelation controlled addition of organometallic nucleophiles
to these alkynols was then affected followed by the addition
of sulfur dioxide. This methodology was used to prepare a
number of oxathiolene oxides which have been screened as NQO1
(quinone oxidoreductase) inducers.
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Preparation and Structures of Isoindolone- or Pyrimidone Condensed
Hetero-Cycles Containing a Hydroxy Group on a Cyclohexane
or Norbornane Moiety
Ferenc Miklós, Pál Sohár,
Antal Csámpai, Reijo Sillanpää and Géza
Stájer
With DL-valinol, 3-amino-1-propanol and o-aminothiophenol,
aroyl(bi/tri)cyclic lactones 1 and 2
were cyclized to isoindole- 4-6, 8, 9, pyrimidinone-
10 or thiazepine- 7 condensed
heterocycles. The ketal lactone 3 furnished
the benzthiazoloisoindole 9 and mixtures
of epimeric hydroxyphthalazinoquinazolinones 11
and 12. The structures were established by
means of 1H and 13C
NMR spectroscopy and in some cases by X-ray crystallography.
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Chiral Recognition of 2-Hydroxypropyl-alpha-cyclodextrin Towards
DL-Tryptophan
Luiz Fernando B. Malta, Jaqueline D. Senra,
Luzineide W. Tinoco, M.E. Medeiros and Octavio A.C.
Antunes
In this report, the recognition points of tryptophan
by 2-hydroxypropyl-alpha-cyclodextrin (HPαCD)
are presented. This cyclodextrin exhibited greater thermodynamic
chiral selectivity towards DL-tryptophan than the hydroxypropylated
beta form. FTIR spectroscopy was used to tentatively evidence
this chiral discrimination in solid state HPαCD-Trp
complexes. An inclusion complex was only detected for the
HPαCD-DTrp
sample, while HPαCD-LTrp
immediately decomposed after crystallization, which left a
mechanical mixture of tryptophan and cyclodextrin.
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α-Pinene-Based
New Chiral Ionic Liquids and their Application as Phase Transfer
Catalysts in Enantioselective Addition of Diethylzinc to Aldehydes
Sanjay V. Malhotra, Yun Wang and Vineet
Kumar
Amino alcohol functionalized new chiral ionic liquids
have been synthesized from (+)-α-pinene,
an easily available natural product. The effectiveness of
these CILs as phase transfer catalysts (PTC) in enantioselective
C-C bond formation has been demonstrated through the addition
of diethylzinc to representative aldehydes, and the corresponding
chiral alcohols with good yields and enantiomeric excess have
been obtained.
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