Letters in Organic Chemistry

ISSN: 1570-1786

Letters in Organic Chemistry
Volume 6, Number 2, March 2009


Contents


Synthesis of C₂-Symmetric Glycophanes Through a 'Click Chemistry' Approach Pp. 106-109
Gildas R. Balou, Jean-Pierre Joly, Lionel Vernex-Loset and Yves Chapleur
[Abstract] [Supplementary Material] [Purchase Article]


A Study of the Influence of Base, Temperature and Reaction Time in Nitroaldol Reactions Using (R)-(+)-Glyceraldehyde Acetonide: Diastereoselective Synthesis of (4R, 5R)-Dihydro-5-((R)-1,2- Dihydroxyethyl)-4-Nitrofuran-2(3H)-one Pp. 110-114
Érica V. Pennaforte, Jeronimo S. Costa, Cristiane A. Silva, Marcelo C. Saraiva and Vera L. Patrocinio Pereira
[Abstract] [Purchase Article]


Synthesis of Alkyl β-Glucosides by Transglucosylation Using Pyrococcus furiosus β-Glucosidase Immobilized onto Gelatin Gel Pp. 115-119
Yoh-ichi Matsushita, Hidetaka Nagatomo, Kazuhiro Sugamoto and Takanao Matsui
[Abstract] [Purchase Article]


Induced Circular Dichroism and Conformational Analysis of 2,2’- Binaphthyl Esters Derived from Primary Alcohols Possessing a Stereogenic Center in the β-Position Pp. 120-125
Shinzo Hosoi, Takeyuki Tanaka, Ichiro Takahashi, Akiyo Sakushima and Yukiteru Katsumoto
[Abstract] [Purchase Article]


Microwave-Promoted Rearrangement of Hecogenin Derivatives into C-nor-D-homo Steroids Pp. 126-129
Zhou Huan, Yue Pei, Ruan Hanli, Zhang Yonghui, Pi Huifang, Zhang Peng and Wu Jizhou
[Abstract] [Purchase Article]


Synthesis of Tipranavir Analogues as Non-Peptidic HIV Protease Inhibitors Pp. 130-133
Yili Ding, Chamakura V.N.S. Vara Prasad, Kenneth L. Smith, Eugene Chang, Jian Hong and Nanhua Yao
[Abstract] [Purchase Article]


Synthesis of 4-(5-Benzyl-2-phenylpyrimidin-4-yl)morpholines as Novel PI3K Inhibitors Via Acetates of Baylis-Hillman Adducts and Benzamidines Pp. 134-140
Chunhao Yang, Haofei Yu, Na Yang, Linghua Meng, Jing Xu, Rongping Zhang, Yuyuan Xie and Jian Ding
[Abstract] [Purchase Article]


Design and Synthesis of New Cap Analogs Containing 2'-OH Modifications on Both Guanosine and m⁷Guanosine Moieties Pp. 141-144
Anilkumar R. Kore and Muthian Shanmugasundaram
[Abstract] [Purchase Article]


An Easy Approach to the Synthesis of New Fused 3-Aryl-5- trifluoromethyl-7,8-dihydro-6H-thieno [2,1-f] [1,2] thiazine 1-Oxide System Pp. 145-150
Helio G. Bonacorso, Renata P. Vezzosi, Roberta L. Drekener, Nilo Zanatta and Marcos A. P. Martins
[Abstract] [Purchase Article]


An Efficient ZrCl₄ Catalyzed Aza-Michael Addition Reaction: Synthesis of C-Linked Carbo β³-Amino Acids Pp. 151-155
Krishna Damera, Katta L. Reddy and Gangavaram V.M. Sharma
[Abstract] [Purchase Article]


A Practical Procedure for Efficient Synthesis of α-Amino Acids Pp. 156-158
Shouxin Liu, Debin Ji, Yihua Yang, Xiaoli Zhen, Xia Tian and Jianrong Han
[Abstract] [Purchase Article]


Bismuth Nitrate Promoted Fischer Indole Synthesis: A Simple and Convenient Approach for the Synthesis of Alkyl Indoles Pp. 159-164
Aralihalli Sudhakara, Honnali Jayadevappa, Hosanagara N.H. Kumar and Kittappa M. Mahadevan
[Abstract] [Purchase Article]


One-pot Synthesis of 2-Substituted Imidazo[2,1-b][1,3]benzothiazoles Via Coupling-Cyclization Under Pd-Cu Catalysis in Water Pp. 165-170
Mohammad Bakherad, Ali Keivanloo and Mahdieh Hashemi
[Abstract] [Purchase Article]


Halogen Dance and Sequential Cross-Coupling on 2 Anilinothiazoles Pp. 171-174
Ather F. Khan, Michael Schnürch, Marko D. Mihovilovic and Peter Stanetty
[Abstract] [Purchase Article]


Efficient Hydrolysis of Nitriles to Amides with Hydroperoxide Anion in Aqueous Surfactant Solutions as Reaction Medium Pp. 175-179
Lucia Brinchi, Lisa Chiavini, Laura Goracci, Pietro Di Profio and Raimondo Germani
[Abstract] [Purchase Article]


Mechanism and Stereoselectivity of the Phosphinylation of 3-Acyl Coumarins - Stereocontrol Via Concurrent Aromatic Interaction/Oxaphosphole Formation Pp. 180-185
Petar Y. Petrov, Nikolay G. Vassilev, Silvia E. Angelova, Boris L. Shivachev and Galin P. Petrov
[Abstract] [Purchase Article]




Abstracts



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Synthesis of C₂-Symmetric Glycophanes Through a 'Click Chemistry' Approach
Gildas R. Balou, Jean-Pierre Joly, Lionel Vernex-Loset and Yves Chapleur
[Supplementary Material]

The synthesis of C₂-symmetric glycophanes incorporating two triazole linkers has been achieved in seven steps from 3,4,6-tri-O-acetyl-D-glucal in good overall yields. The intermolecular Cu(I)-mediated Huisgen reaction was used for the ring closure key-step to give almost exclusively 24-, 26-, and 32-membered chiral macrocycles without significant polymerization. Target compounds however had low solubility in water, precluding investigation of their recognition behaviour in this medium.


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A Study of the Influence of Base, Temperature and Reaction Time in Nitroaldol Reactions Using (R)-(+)-Glyceraldehyde Acetonide: Diastereoselective Synthesis of (4R, 5R)-Dihydro-5-((R)-1,2- Dihydroxyethyl)-4-Nitrofuran-2(3H)-one
Érica V. Pennaforte, Jeronimo S. Costa, Cristiane A. Silva, Marcelo C. Saraiva and Vera L. Patrocinio Pereira

The Henry reaction between the nitroalkanes 6-11 and (R)-(+)-glyceraldehyde acetonide (1), was investigated in respect to the variation of the base, temperature and reaction time. Nitroalcohols 5a-f were obtained in good yields (70-85%) and moderate to good anti-selectivities (50-79%). The transformation of the nitroalcohol 5a,b in title γ-lactone 2, a potential precursor of bioactive β-aminoacids, was also investigated.


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Synthesis of Alkyl β-Glucosides by Transglucosylation Using Pyrococcus furiosus β-Glucosidase Immobilized onto Gelatin Gel
Yoh-ichi Matsushita, Hidetaka Nagatomo, Kazuhiro Sugamoto and Takanao Matsui

Synthesis of alkyl β-glucosides such as p-anisyl β-D-glucopyranoside, phenethyl β-D-glucopyranoside, salidroside, cinnamyl β-D-glucopyranoside, citrusin D, 3-methylbutyl β-D-glucopyranoside, 3-methyl-2-butenyl β-D-glucopyranoside, geranyl β-D-glucopyranoside, perilloside A, and cyclohexyl β-D-glucopyranoside was accomplished in moderate yields by transglucosylation using hyperthermostable Pyrococcus furiosus β-glucosidase immobilized onto gelatin gel. Recovered immobilisate was reusable on successive runs in transglucosylation.


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Induced Circular Dichroism and Conformational Analysis of 2,2’- Binaphthyl Esters Derived from Primary Alcohols Possessing a Stereogenic Center in the β-Position
Shinzo Hosoi, Takeyuki Tanaka, Ichiro Takahashi, Akiyo Sakushima and Yukiteru Katsumoto

Circular dichroism calculations and conformational analyses of 2,2’-binaphthyl esters derived from primary alcohols with a chiral center in the β-position of the hydroxy group were performed using the time-dependent density functional theory (TD-DFT) method, suggesting that the TD-DFT is highly effective for determining the absolute configuration of the binaphthyl esters.


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Microwave-Promoted Rearrangement of Hecogenin Derivatives into C-nor-D-homo Steroids
Zhou Huan, Yue Pei, Ruan Hanli, Zhang Yonghui, Pi Huifang, Zhang Peng and Wu Jizhou

By means of microwave irradiation, the rearrangement from 12β-tosylate and 12β-alcohol of hecogenin derivatives into C-nor-D-homo-Δ^17a(18)-olefin (2) and the Δ^13(17a)-isomer (3) was achieved. With this method, the controlled solvolysis in anhydrous pyridine gave total conversion to desired exocyclic-olefin which is expected to be a building block of isosteroidal alkaloids.


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Synthesis of Tipranavir Analogues as Non-Peptidic HIV Protease Inhibitors
Yili Ding, Chamakura V.N.S. Vara Prasad, Kenneth L. Smith, Eugene Chang, Jian Hong and Nanhua Yao

An analogue of Tipranavir was designed by replacing the dihydropyrone core with a 1,3-cyclohexanedione ring. The thio-alkyl group was used as a temporary protection group for α, β-unsaturated cyclohexane-1,3-diketone derivative, and the resulting compound was reacted with an ethyl-organometallic reagent to form the desired Michael addition product. By using this strategy, a more stable analogue of Tipranavir was synthesized and exhibited excellent HIV protease inhibition (12 nM Ki).


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Synthesis of 4-(5-Benzyl-2-phenylpyrimidin-4-yl)morpholines as Novel PI3K Inhibitors Via Acetates of Baylis-Hillman Adducts and Benzamidines
Chunhao Yang, Haofei Yu, Na Yang, Linghua Meng, Jing Xu, Rongping Zhang, Yuyuan Xie and Jian Ding

The key intermediates 5-benzyl-2-phenylpyrimidin-4(3H)-ones or (E)-5-benzylidene-2-phenyl- 5,6-dihydro-pyrimidin-4(3H)-ones were obtained conveniently by cyclization of the acetates of Baylis–Hillman adducts and benzamidine hydrochloride in the presence of sodium ethoxide at room temperature. Chlorination of pyrimidinones with phosphorus oxychloride and subsequent treatment with morpholine and demethylation yielded PI3K inhibitors.


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Design and Synthesis of New Cap Analogs Containing 2'-OH Modifications on Both Guanosine and m⁷Guanosine Moieties
Anilkumar R. Kore and Muthian Shanmugasundaram

Synthesis of new cap analogs containing 2'-OH modifications on both guanosine and m⁷guanosine moieties such as m₂^7,2'OG[5']ppp[5']m^2'OG and 2'-OH modifications on both m⁷guanosine moieties such as m₂^7,2'OG[5']ppp[5'] m₂^7,2'OG are reported. Structures were confirmed by ¹H and ³¹P NMR and mass spectral data.


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An Easy Approach to the Synthesis of New Fused 3-Aryl-5- trifluoromethyl-7,8-dihydro-6H-thieno [2,1-f] [1,2] thiazine 1-Oxide System
Helio G. Bonacorso, Renata P. Vezzosi, Roberta L. Drekener, Nilo Zanatta and Marcos A. P. Martins

A new series of 4-alkyl(aryl)-4-tetramethylenesulfoximide-1,1,1-trifluoroalk-3-en-2-ones has been prepared from the O,N-exchange reactions of 4-alkyl(aryl)-4-alkoxy-1,1,1-trifluoroalk-3-en-2-ones with the cyclic S,S-te-tramethylenesulfoximide in absence of solvent, in good yields. Subsequently, the easy preparation of a new series of a fused heterocyclic system of 3-aryl-5-trifluoromethyl-7,8-dihydro-6H-thieno[2,1-f][1,2]thiazine 1-oxide derivatives (60-85% yields) from intramolecular cyclization reactions of sulfoximide enones employing potassium t-butoxide in diethyl ether at reflux is also reported.


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An Efficient ZrCl₄ Catalyzed Aza-Michael Addition Reaction: Synthesis of C-Linked Carbo β³-Amino Acids
Krishna Damera, Katta L. Reddy and Gangavaram V.M. Sharma

A mild aza-Michael protocol has been developed using ZrCl₄ as catalyst on α, β-unsaturated esters and nitriles. The aromatic amines were found to give the products with ease. The ZrCl₄ mediated route was compatible with acid sensitive carbohydrate esters and provided an efficient method to prepare C-linked carbo β³-amino acids (β³-Caa).


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A Practical Procedure for Efficient Synthesis of α-Amino Acids
Shouxin Liu, Debin Ji, Yihua Yang, Xiaoli Zhen, Xia Tian and Jianrong Han

An effective method to prepare racemic α-amino acids was developed. The key reactions involve nitrosation of malonate under basic conditions and reduction of α-hydroxyimino ester derivatives with zinc powder in the presence of acetic anhydride.


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Bismuth Nitrate Promoted Fischer Indole Synthesis: A Simple and Convenient Approach for the Synthesis of Alkyl Indoles
Aralihalli Sudhakara, Honnali Jayadevappa, Hosanagara N.H. Kumar and Kittappa M. Mahadevan

A novel one-pot fisher indole synthesis approach has been developed by using bismuth nitrate as a catalyst. Yields around 90-95% were obtained after reaction in methanol at reflux temperature in 20-40 min. Apart from the mild reaction conditions of the process and its excellent results, the simplicity of product isolation and the possibility to recycle the bismuth nitrate offers a significant advantage.


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One-pot Synthesis of 2-Substituted Imidazo[2,1-b][1,3]benzothiazoles Via Coupling-Cyclization Under Pd-Cu Catalysis in Water
Mohammad Bakherad, Ali Keivanloo and Mahdieh Hashemi

The reaction of 2-imino-3-(2-propynyl)-1,3-benzothiazole with various aryl iodides, catalyzed by Pd-Cu, in the presence of sodium lauryl sulfate as the surfactant and potassium carbonate as the base, in water, leads to the formation of 2-substituted imidazo[2,1-b][1,3]benzothiazoles.


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Halogen Dance and Sequential Cross-Coupling on 2 Anilinothiazoles
Ather F. Khan, Michael Schnürch, Marko D. Mihovilovic and Peter Stanetty

A series of 4-bromo-5-halo and 4-bromo-5-organometal-2-anilinothiazole derivatives were prepared via the halogen dance (HD) reaction. Subsequent Pd-catalyzed Stille and Suzuki-Miyaura cross-coupling reactions were performed in a sequential manner to obtain novel 4,5-diarylated-2-anilinothiazoles.


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Efficient Hydrolysis of Nitriles to Amides with Hydroperoxide Anion in Aqueous Surfactant Solutions as Reaction Medium
Lucia Brinchi, Lisa Chiavini, Laura Goracci, Pietro Di Profio and Raimondo Germani

Aliphatic and aromatic nitriles are converted to corresponding amides in a single step via hydrolysis with basic H₂O₂ in aqueous solution of the surfactant Cetyltrimethylammonium methanesulfonate (CTAOMs). The method has several advantages: use and recycle of water as reaction medium, use of environmentally benign oxidant H₂O₂, easy product isolation, short reaction time, high yields and selectivity, mild conditions.


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Mechanism and Stereoselectivity of the Phosphinylation of 3-Acyl Coumarins - Stereocontrol Via Concurrent Aromatic Interaction/Oxaphosphole Formation
Petar Y. Petrov, Nikolay G. Vassilev, Silvia E. Angelova, Boris L. Shivachev and Galin P. Petrov

Racemic P-acetoxy-P-chloro phenylphosphonite reacts with prochiral 3-acylcoumarins yielding (2R,3R)/(2S,3S)-coumarino-3,4-c-2-oxo-2-phenyl-1,2-3H-oxaphospholes with >99% regio- and diastereoselectivity. The stereoselectivity is governed by the presence of phophonite phenyl group and oxaphosphole ring formation. The product has suitable conformation providing stereoselective route to (R,S)/(S,R) phosphino-substituted coumarins, normally inaccessible by the Phospha-Michael reaction employing achiral reagents.