Letters in Organic Chemistry

ISSN: 1570-1786

Letters in Organic Chemistry
Volume 6, Number 5, July 2009


Contents


Synthesis of Imidazoles from Ketimines Using Tosylmethyl Isocyanide (TosMIC) Catalyzed by Bismuth Triflate Pp. 354-358
Mokhtar Fodili, Bellara Nedjar-Kolli, Bernard Garrigues, Christian Lherbet and Pascal Hoffmann
[Abstract] [Purchase Article]


Synthesis of Polysubstituted Pyrroles Pp. 259-361
Céline Poulard, Julien Cornet, Stéphanie Legoupy, Gilles Dujardin, Robert Dhal and François Huet
[Abstract] [Purchase Article]


Isolation and syn Elimination of a Peterson Adduct to Obtain Optically Pure Product in the Diastereoselective Synthesis of Oxazolidinone-Functionalized Enecarbamates Pp. 362-366
Marissa R. Solomon, Hideaki Saito, J. Sivaguru, Steffen Jockusch, Yoshihisa Inoue, Waldemar Adam and Nicholas J. Turro
[Abstract] [Purchase Article]


Azaphilone α-Bromoacetates (AzαBs): Fluorescent Linchpin Reagents for the Inter- and Intramolecular Cross-Linkage of Primary Amines to Thiols Pp. 367-371
Jason J. Chruma, Sung-Ju Moon and William E. Sanford, Jr.
[Abstract] [Purchase Article]


Tandem Generation and Trapping of Furo[3,4-c]isoquinoline Inter-mediates Leading to the Synthesis of Phenanthridine Ring Systems Pp. 372-376
Gouranga P. Jana and Binay K. Ghorai
[Abstract] [Purchase Article]


Asymmetric α-Amination of Aldehydes and Ketones Catalyzed by tert-Butoxy-L-Proline Pp. 377-380
Ramzi Ait-Youcef, Delphine Kalch, Xavier Moreau, Christine Thomassigny and Christine Greck
[Abstract] [Purchase Article]


Regioselective Three-Component Synthesis of Indolylpyrazolo [3,4-b]pyridines Induced by Microwave and under Solvent-Free Conditions Pp. 381-383
Jairo Quiroga, Jorge Trilleras, Ana Isabel Sánchez, Braulio Insuasty, Rodrigo Abonía, Manuel Nogueras and Justo Cobo
[Abstract] [Purchase Article]


Solvent-Free Synthesis of 1,3-Diphenyl-5-arylpyrazole Derivatives Pp. 384-386
Ji-Tai Li, Ying Yin and Xian-Tao Meng
[Abstract] [Purchase Article]


Revised Structure of Penicillazine and Preparation, Bioactivities of Penicillazine Derivatives Pp. 387-391
Chang-Lun Shao, Chang-Yun Wang, Yu-Cheng Gu, Ji-Wen Cai, Dong-Sheng Deng, Zhi-Gang She and Yong-Cheng Lin
[Abstract] [Purchase Article]


Asymmetric Catalysis of Diels-Alder Cycloaddition of 2-Alkenoyl Pyridine with Cyclopentadiene by Binaphthol-Titanium Complex Pp. 392-396
Li Wang, Ji Zhang, Na Wang, Xin-Bin Yang, Qin Wang and Xiao-Qi Yu
[Abstract] [Purchase Article]


Enantioselective Conjugate Addition of N-Heterocycles to α,β-Enones Mediated by Diarylprolinols Pp. 397-399
Ling Fang, Aijun Lin, Xuefeng Jia, Jie Meng, Yangnian Wang and Chengjian Zhu
[Abstract] [Purchase Article]


Triselenium Dicyanide (TSD): A New Catalyst for the Facile Synthesis of Heteroins Including Pteroin and Quinoxaloin under Microwave Heating Pp. 400-403
Shyamaprosad Goswami and Annada C. Maity
[Abstract] [Purchase Article]


A Simple Highly Regioselective or Regiospecific Substitution Method of Aromatic Isoquinoline Pp. 404-408
Yu-An Chang and Hsiang Chang
[Abstract] [Purchase Article]


A Novel Fluorescent Calix[4]arene Derivative with Benzimidazole Units For Selective Recognition to Fe³⁺ and Cr³⁺ Pp. 409-411
He Wen Wang, Ya Qing Feng and Jin Qiang Xue
[Abstract] [Purchase Article]


The Influence of Substituents on the Hydroxyl-Bearing Carbon in the Aza-Payne Rearrangement of Aziridinemethanols Pp. 412-415
Wenjin Xu, Jun Zhang, Hao Guo, Qifeng Zhu and Xianming Hu
[Abstract] [Purchase Article]


Perfluoroalkylsulfonyloxyisoflavones: Synthesis and Anti Proliferation of HL-60 Pp. 416-418
Hongqi Li and Ye Jin
[Abstract] [Purchase Article]


Synthesis and Hydroxyapatite Binding Activity of Bisphosphonate- Statin Conjugates Pp. 419-423
Guangyu Xu, Gaolei Zuo, Shihua Zhong and Wei Zhang
[Abstract] [Purchase Article]


Photo-Catalytic Oxidation of Benzyl Alcohols Using Oxone^® in the Presence of n-Bu₄NBr in Water Pp. 424-427
Shang Wu, Hengchang Ma, Penghua Yan, Jianqiang Wang, Juanjuan Ding and Ziqiang Lei
[Abstract] [Purchase Article]


Isolation, Characterization and Hypoglycemic Activity of an Acid Polysaccharide Isolated from Schisandra chinensis (Turcz.) Baill Pp. 428-433
Xiaoxv Gao, Xianjun Meng, Jihai Li and Haibin Tong
[Abstract] [Purchase Article]




Abstracts


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Synthesis of Imidazoles from Ketimines Using Tosylmethyl Isocyanide (TosMIC) Catalyzed by Bismuth Triflate
Mokhtar Fodili, Bellara Nedjar-Kolli, Bernard Garrigues, Christian Lherbet and Pascal Hoffmann

The preparation of a series of 1,5-disubstituted-4-methyl imidazoles is reported, based on an unprecedented reaction between an acetimine and TosMIC in the presence of tert-butylamine and catalytic amounts of bismuth(III) triflate. The mechanism is believed to involve formation of an imidazoline intermediate, followed by the methyl group migration, and subsequent aromatization to the imidazole ring.


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Synthesis of Polysubstituted Pyrroles
Céline Poulard, Julien Cornet, Stéphanie Legoupy, Gilles Dujardin, Robert Dhal and François Huet

Cross coupling metathesis reactions from two ethylenic compounds 4 and 5 easily led to Michael acceptors 6a-b and 7a-b. Reaction of these compounds, or of enone 5’, with p-toluenesulfonylmethyl isocyanide (TosMIC) provided the disubstituted pyrroles 9a-c and 10a-b. The analogous reaction of compounds 6a-b and 5’, but in presence of Ph3SnCl, provided the trisubstituted pyrroles 11a-c. All of these compounds 9-11 were thus obtained in two steps only.


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Isolation and syn Elimination of a Peterson Adduct to Obtain Optically Pure Product in the Diastereoselective Synthesis of Oxazolidinone-Functionalized Enecarbamates
Marissa R. Solomon, Hideaki Saito, J. Sivaguru, Steffen Jockusch, Yoshihisa Inoue, Waldemar Adam and Nicholas J. Turro

The Peterson reaction of (4R)-N-(trimethylsilyl)methyl-4-alkyloxazolidin-2-one gives (E/Z)-(4R)-N-(2’,3’-diphenylbut-1’-enyl)-4-alkyloxazolidin-2-ones (enecarbamates) with increasing (Z)-selectivity and moderate-to-high diastereoselectivity in the individual E isomer as a function of increasing temperature. X-ray structure of the Peterson adduct, (4R,3’S)-N-(2’,3’-diphenyl-2’-hydroxy-but-1’-enyl)-4-alkyloxazolidin-2 one (enecarbamates), reveals the rationale for the formation of a single isomer through syn elimination. The optically pure enecarbamates obtained with the Peterson adduct were further employed for photochemical and photophysical studies.


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Azaphilone α-Bromoacetates (AzαBs): Fluorescent Linchpin Reagents for the Inter- and Intramolecular Cross-Linkage of Primary Amines to Thiols
Jason J. Chruma, Sung-Ju Moon and William E. Sanford, Jr.

α-Bromoacetate esters of the azaphilone isochromene-6,8-dione core exhibit a pH-dependent orthogonal reactivity allowing for the one-pot cross-linkage of primary amines to thiols in an inter- or intramolecular fashion to afford fluorescent products. This represents a new potential strategy for bioconjugate chemistry.


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Tandem Generation and Trapping of Furo[3,4-c]isoquinoline Inter-mediates Leading to the Synthesis of Phenanthridine Ring Systems
Gouranga P. Jana and Binay K. Ghorai

One pot three component coupling of 3-alkynyl-4-isoquinoline carbonyl derivatives with Fischer carbene complexes and dienophiles leading to the synthesis of phenanthridine ring system has been investigated. This reaction involves the generation of furo[3,4-c]isoquinolines as transient intermediates, which undergo [4+2] cycloaddition with a dienophile in an inter/intramolecular fashion. In fact, this is the first report of the work on furo[3,4-c]isoquinoline intermediates.


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Asymmetric α-Amination of Aldehydes and Ketones Catalyzed by tert-Butoxy-L-Proline
Ramzi Ait-Youcef, Delphine Kalch, Xavier Moreau, Christine Thomassigny and Christine Greck

Asymmetric electrophilic α-amination of aldehydes and ketones is described using trans-3-tert-butoxy-L-proline and trans-4-tert-butoxy-L-proline as efficient catalysts. Good yields and high enantioselectivities are obtained working at 0°C or at room temperature with a catalyst loading of only 5 mol%.


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Regioselective Three-Component Synthesis of Indolylpyrazolo [3,4-b]pyridines Induced by Microwave and under Solvent-Free Conditions
Jairo Quiroga, Jorge Trilleras, Ana Isabel Sánchez, Braulio Insuasty, Rodrigo Abonía, Manuel Nogueras and Justo Cobo

New 4-(1H-indol-3-yl)-6-arylpyrazolo[3,4-b]pyridines 7 have been prepared in a solvent-free three-component reaction induced by microwave from 5-aminopyrazole 1, benzaldehydes 2 and 3-indolyl-3-oxopropanenitrile 5. These compounds were also obtained by means of the reaction of aminopyrazole 1 with benzylidene-derivatives of 3-(1H-indol-3-yl)-3-oxopropanenitrile 6, prepared in the reaction of 3-(1H-indol-3-yl)-3-oxopropanenitrile and aldehydes.


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Solvent-Free Synthesis of 1,3-Diphenyl-5-arylpyrazole Derivatives
Ji-Tai Li, Ying Yin and Xian-Tao Meng

The synthesis of 1,3-diphenyl-5-arylpyrazoles via the reactions of 2,3-epoxy-1-phenyl-3-aryl-1-propanones with phenylhydrazine was carried out in 48-84% yields at 230 °C under solvent-free condition within 1.5 h. This method provides several advantages such as operational simplicity, higher yield and solvent-free.


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Revised Structure of Penicillazine and Preparation, Bioactivities of Penicillazine Derivatives
Chang-Lun Shao, Chang-Yun Wang, Yu-Cheng Gu, Ji-Wen Cai, Dong-Sheng Deng, Zhi-Gang She and Yong-Cheng Lin

The structure of penicillazine has been revised on the basis of hydrolysis reaction. Its absolute stereochemistry has been confirmed by X-ray diffraction using copper radiation. Eight new penicillazine derivatives (1-8) were prepared and some of them showed higher levels of activity than penicillazine against α-glucosidase and Human DNA topoisomerase I.


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Asymmetric Catalysis of Diels-Alder Cycloaddition of 2-Alkenoyl Pyridine with Cyclopentadiene by Binaphthol-Titanium Complex
Li Wang, Ji Zhang, Na Wang, Xin-Bin Yang, Qin Wang and Xiao-Qi Yu

Asymmetric Diels-Alder reactions between aza-chalcone and cyclopentadiene (CP) catalyzed by the binaphthol-titanium (BINOL–Ti) in the presence of HMPA (80 mole %) were studied. The products were obtained with up to 87% ees.


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Enantioselective Conjugate Addition of N-Heterocycles to α,β-Enones Mediated by Diarylprolinols
Ling Fang, Aijun Lin, Xuefeng Jia, Jie Meng, Yangnian Wang and Chengjian Zhu

Enantioselective conjugate addition of benzotriazole to α,β-enones catalyzed by prolinol derivatives with moderate yields and enantioselectivities was reported. Studies of stereoelectronic effects of the catalyst showed that the transition state could be of a hydrogen bonding activation mode, and fine tuning of the substituents on the aryl moiety of the catalyst is important for the reaction stereoselectivities.


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Triselenium Dicyanide (TSD): A New Catalyst for the Facile Synthesis of Heteroins Including Pteroin and Quinoxaloin under Microwave Heating
Shyamaprosad Goswami and Annada C. Maity

Triselenium dicyanide (TSD) under microwave heating has been reported herein for the first time to be an efficient catalyst for the benzoin type condensation reaction and this has been applied for the synthesis of heteroins such as pteroin, quinoxaloin, quinoloin and pyridoin in moderate to good yields. Heteroin is produced by the dimerization of two molecules of N-heterocyclic aldehyde.


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A Simple Highly Regioselective or Regiospecific Substitution Method of Aromatic Isoquinoline
Yu-An Chang and Hsiang Chang

A novel simple version for highly regioselective or regiospecific substitution method of aromatic isoquinoline has been developed by utilizing the reaction condition of Bischler-Napieralski cyclization. The proposed reaction mechanism was successfully indirect confirmed. In this method, chloroiminium intermedium A was formed from the amide compound with phosphoryl chloride, and intramolecular cyclized was preceded. The final structure of aromatic isoquinoline was obtained through removing the acidic hydrogen atom by sodium borohydride served as a base rather than reductive agent as expected.


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A Novel Fluorescent Calix[4]arene Derivative with Benzimidazole Units For Selective Recognition to Fe³⁺ and Cr³⁺
He Wen Wang, Ya Qing Feng and Jin Qiang Xue

A novel fluorescent calix[4]arene derivative(1) with benzimidazole units as fluorophores and imino groups as ionophores at the upper rim has been synthesized in the cone conformation. Compound (1) was fully characterized by ¹H-NMR, ¹³C-NMR, IR and MS. The changes of UV-Vis spectra and fluorescent spectra upon metal ions complexation show compound (1) can selectively recognize Fe³⁺ and Cr³⁺ ions. The complexation ratio of compound (1) and Fe³⁺ or Cr³⁺ is 1:1. The association constant of compound (1) for Fe³⁺ was 3.4×10⁴ and for Cr³⁺ was 2.8×10⁵.


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The Influence of Substituents on the Hydroxyl-Bearing Carbon in the Aza-Payne Rearrangement of Aziridinemethanols
Wenjin Xu, Jun Zhang, Hao Guo, Qifeng Zhu and Xianming Hu

A new series of α,α-disubstituted aziridinemethanols have been synthesized and their aza-Payne rearrangement reactions were studied. The results show that α,α-disubstituted aziridinemethanols with electron-withdrawing groups accelerate the aza-Payne rearrangement than those with electron-donating groups. All of the rearrangements proceeded through an inversion of configuration at the C-2 carbon.


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Perfluoroalkylsulfonyloxyisoflavones: Synthesis and Anti Proliferation of HL-60
Hongqi Li and Ye Jin

Isoflavonoids containing a perfluoroalkylsulfonyloxy group were synthesized by perfluoroalkylsulfonylation of hydroxyisoflavones. The reaction showed high regioselectivity. Inhibitory effects of the synthesized isoflavones against proliferation of HL-60 and BEL-7402 cells were tested in vitro. Two isoflavones displayed strong inhibitory effect on HL-60 cells.


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Synthesis and Hydroxyapatite Binding Activity of Bisphosphonate- Statin Conjugates
Guangyu Xu, Gaolei Zuo, Shihua Zhong and Wei Zhang

To develop a methodology for delivering anabolic agents statins to bone, a bone targeting bisphosphonate was used as a carrier of drugs. Four statin-bisphosphonate conjugates were synthesized and examined for their bone mineral affinity in vitro by hydroxyapatite absorption method. The conjugates showed high binding activity with HAP, implying the modified statins possess the potential of bone targeting property.


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Photo-Catalytic Oxidation of Benzyl Alcohols Using Oxone^® in the Presence of n-Bu₄NBr in Water
Shang Wu, Hengchang Ma, Penghua Yan, Jianqiang Wang, Juanjuan Ding and Ziqiang Lei

A simple, mild and efficient method has been developed for the oxidation of alcohols to aldehydes and ketones using Oxone^® as oxidant catalyzed by n-Bu₄NBr at room temperature in water under UV lamp for 1 h. Oxone^® smoothly oxidizes benzyl alcohol and its derivatives, benzhydrol and its derivatives.


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Isolation, Characterization and Hypoglycemic Activity of an Acid Polysaccharide Isolated from Schisandra chinensis (Turcz.) Baill
Xiaoxv Gao, Xianjun Meng, Jihai Li and Haibin Tong

The crude polysaccharide (SCP) extracted from Schisandra chinensis by hot water extraction and ethanol precipitation, was further fractionated by DEAE-cellulose and Sephacryl S-300 chromatography, giving a polysaccharide fraction named as SCP-BII. The molecular weight of SCP-BII was 23 kDa using HPGPC. Gas chromatography analysis suggested that SCP-BII was composed of rhamnose, arabinose, mannose, galactose, glucose and galacturonic acid with a ratio of 4.7:2.6:0.8:5.6:1:5.6. Pharmaceutical experiments showed SCP-BII administered in alloxan-induced diabetic mice can significantly reduce blood glucose levels and water intake, and increase the body weight of diabetic mice. The results suggest SCP-BII attenuated the diabetes-induced weight loss, polydipsia and hyperglycemia, and these improvements suggest that Schisandra chinensis could be considered as a potential anti-diabetic agent.