Monday, 2 February 2015

Trapping Radicals to Make Acylpyrroles



Trapping Radicals to Make Acylpyrroles

 

Radical processes usually feature mild reaction conditions and good functional group tolerance. However, they usually require hazardous reagents like organotin or azo compounds.

A convenient microwave-promoted synthesis under mild and non-toxic conditions
Read more


http://www.chemistryviews.org/details/news/7297901/Trapping_Radicals_to_Make_Acylpyrroles.html

Monday, 26 January 2015

A Novel and Practical Synthesis of Ramelteon


Ramelteon.svgRAMELTEON
Abstract Image
An efficient and practical process for the synthesis of ramelteon 1, a sedative-hypnotic, is described. Highlights in this synthesis are the usage of acetonitrile as nucleophilic reagent to add to 4,5-dibromo-1,2,6,7-tetrahydro-8H-indeno[5,4-b]furan-8-one 2 and the subsequent hydrogenation which successfully implement four processes (debromination, dehydration, olefin reduction, and cyano reduction) into one step to produce the ethylamine compound 13where dibenzoyl-l-tartaric acid is selected both as an acid to form the salt in the end of hydrogenation and as the resolution agent. Then, target compound 1 is easily obtained from13 via propionylation. The overall yield in this novel and concise process is almost twice as much as those in the known routes, calculated on compound 2.

A Novel and Practical Synthesis of Ramelteon

State Key Lab of New Drug & Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, State Institute of Pharmaceutical Industry, Shanghai 200437,China
Org. Process Res. Dev., Article ASAP
DOI: 10.1021/op500386g
http://pubs.acs.org/doi/abs/10.1021/op500386g
Publication Date (Web): January 6, 2015
Copyright © 2015 American Chemical Society
*Telephone: +86 21 55514600. E-mail: zhouweicheng58@163.com.
Preparation of (S)-N-[2-(1,6,7,8-Tetrahydro-2H-indeno[5,4-b] furan-8-yl)ethyl]propionamide(1).
GAVE
white solid of 1(1.570 g, 85% yield, 99.8% ee). Purity by HPLC 99.6%.
Mp: 115−116 °C(113−115°C in literature 1 ).
Ramelteon.svg
1 H−NMR(400 MHz, CDCl3):
δ 1.39 (t, 3H); 1.63 (m, 1H); 1.83 (m, 1H); 2.02 (m, 1H); 2.16 (dd, J=8, 2H); 2.28 (m, 1H); 2.78 (m, 1H); 2.83 (m, 1H); 3.14 (m, 1H); 3.22 (m, 2H); 3.33 (m, 2H); 4.54 (m, 2H); 5.38 (br s, 1H); 6.61 (d, J=8, 1H); 6.97 (d, J=8, 1H).
Ramelteon.svg
13C−NMR(100 MHz, CDCl3):
δ 173.85, 159.56, 143.26, 135.92, 123.52, 122.28, 107.56, 71.26, 42.37, 38.17, 33.66, 31.88, 30.82, 29.86, 28.73, 10.01.
MS (ES+): m/z 282(M+Na) + .
[α]D −57.3(c=1.0, CHCl3, −57.8 in literature 1 ).
Anal. (C16H21NO2) Calc: C, 74.10; H, 8.16; N, 5.40; found: 74.09; H, 8.17; N, 5.47.
References
(1) Uchikawa, O.; Fukatsu, K.; Tokunoh, R.; Kawada, M.; Matsumoto, K.; Imai, Y.; Hinuma, S.; Kato, K.; Nishikawa, H.; Hirai, K.; Miyamoto M.; Ohkawa, S. J. Med. Chem. 2002, 45, 4222-4239.
(2) Yamano, T.; Yamashita, M.; Adachi, M.; Tanaka, M.; Matsumoto, K.; Kawada, M.; Uchikawa, O.; Fukatsu, K.; Ohkawa, S. Tetrahedron: Asymmetry. 2006, 17, 184-190.
SHANGHAI
SHANGHAI CHINA
The Shanghai International Exhibition Center, an example of Soviet neoclassical architecture in Shanghai

Sunday, 25 January 2015

Bulletin of the Chemical Society of Ethiopia

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http://www.ajol.info/index.php/bcse


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Federal Democratic Republic of Ethiopia
የኢትዮጵያ ፌዴራላዊ ዲሞክራሲያዊ
ሪፐብሊክ

ye-Ītyōṗṗyā Fēdēralāwī Dīmōkrāsīyāwī
Rīpeblīk
FlagEmblem





Coins of the Axumite king Endybis, 227–235 AD, at the British Museum. The inscriptions in Ancient Greek read "AΧWMITW BACIΛEYC" ("King of Axum") and "ΕΝΔΥΒΙC ΒΑCΙΛΕΥC" ("King Endybis").




Mountain nyalas in Nechisar National Park, one of several wildlife reserves in Ethiopia.








EXAMPLE


Journal Home
 > Vol 29, No 1 (2015) > 

Regioselective iodination of aryl amines using 1,4-dibenzyl-1,4-diazoniabicyclo [2.2.2] octane dichloroiodate in solution and under solvent-free conditions

M. Alikarami, S. Nazarzadeh, M. Soleiman-Beigi

Abstract


1,4-Dibenzyl-1,4-diazoniabicyclo[2.2.2]octane dichloroiodate is an efficient and regioselective reagent for iodination of aryl amines. A wide variety of aryl amines in reaction with this reagent afforded regioselectively iodinated products. The iodination reaction can be carried out in solution or under solvent-free condition at room temperature.

KEY WORDS:  Regioselective iodination, Aryl amines, 1,4-Dibenzyl-1,4-diazoniabicyclo [2.2.2] octane dichloroiodate,  Solvent-free conditions

Bull. Chem. Soc. Ethiop. 2015, 29(1), 157-162



Sunday, 11 January 2015

"Pd/NHC-Catalyzed Enantiospecific and Regioselective Suzuki-Miyaura Arylation of 2-Arylaziridines: Synthesis of Enantioenriched 2-Arylphenethylamine Derivatives"



"Pd/NHC-Catalyzed Enantiospecific and Regioselective Suzuki-Miyaura Arylation of 2-Arylaziridines: Synthesis of Enantioenriched 2-Arylphenethylamine Derivatives"
Youhei Takeda*, Yuki Ikeda, Akinobu Kuroda, Shino Tanaka, and Satoshi Minakata*
J. Am. Chem. Soc. 2014136, 8544–8547. DOI: 10.1021/ja5039616 

* Highlighted in Org. Process Res. Dev. as "Some Items of Interest to Process R&D Chemists and Engineers"! !link
Abstract: A palladium-catalyzed stereospecific and regioselective cross-coupling of enantiopure 2-arylaziridines with arylboronic acids under mild conditions to construct a tertiary stereogenic center has been developed. N-heterocyclic carbene (NHC) ligands drastically promote the coupling, suppressing β-hydride elimination. The enantiospecific cross-coupling allowed us for preparation of a series of biologically important 2-arylphenethylamine derivatives in an enantiopure form.

Utilization of N-X bonds in the synthesis of N-heterocycles



Utilization of N-X bonds in the synthesis of N-heterocycles

Simple nitrogen-containing heterocycles could be constructed from carbon-carbon double bond (including fulleren) as carbon resources.

Acc. Chem. Res. 200942, 1172

Application of carbon dioxide to organic synthesis

Application of carbon dioxide to organic synthesis

Carbon dioxide fixation to unsaturated alcohols could be realized under extremely mild conditions by using tert-BuOI.



Angew. Chem. Int. Ed. 2010, 49, 1309.


Haloamidation of olefins induced by carbon dioxide was developed.

Org. Lett. 2006, 8, 967. Org. Bio.mol. Chem. 2010, 8, 1424

Application of water/silica system to organic synthesis



Application of water/silica system to organic synthesis

Organic reactions on silica in water were successfully achieved by utilizing hydrophobic interaction.


Chem. Rev. 2009109, 711. Angew. Chem. Int. Ed. 200443, 79