Revealing the Essentials for Effective β-Glucopyranoside Recognition

Revealing the Essentials for Effective β-Glucopyranoside Recognition

A step forward in the design of synthetic receptors for the recognition of carbohydrates
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Organocatalytic Route to α-Amino Acid Derivatives

Both enantiomers of substituted α-amino acid derivatives selectively synthesized
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A highly efficient approach to vanillin starting from 4-cresol

A highly efficient approach to vanillin starting from 4-cresol

Green Chem., 2014, 16,2807-2814
DOI: 10.1039/C4GC00003J, Paper

Jian-An Jiang, Cheng Chen, Ying Guo, Dao-Hua Liao, Xian-Dao Pan, Ya-Fei Ji
A highly efficient three-step approach to vanillin has been developed starting from 4-cresol.

A highly efficient approach to the famous flavor and fragrance compound vanillin has been developed starting from 4-cresol with the attention focused on improving the sustainability of all the reactions. The approach involves a three-step sequence of the quasi-quantitative selective clean oxybromination of 4-cresol, the high-yield selective aerobic oxidation of 2-bromo-4-cresol, and the quantitative methoxylation of 3-bromo-4-hydroxybenzaldehyde with the recovery of pure methanol. Herein, the pivotal oxidation and methoxylation reactions are logically investigated and developed into two concise methodologies. As a green alternative, the approach holds significant value for the sustainable manufacturing of vanillin.

Au catalyzed synthesis of benzimidazoles from 2-nitroanilines and CO2/H2

Au catalyzed synthesis of benzimidazoles from 2-nitroanilines and CO2/H2

http://pubs.rsc.org/en/Content/ArticleLanding/2014/GC/C4GC00153B?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Green Chem., 2014, Advance Article
DOI: 10.1039/C4GC00153B, Paper

Leiduan Hao, Yanfei Zhao, Bo Yu, Hongye Zhang, Huanjun Xu, Zhimin Liu
The gold-catalyzed synthesis of benzimidazoles from 2-nitroanilines and CO₂ in the presence of H₂ was reported, and a series of benzimidazoles were obtained under relatively mild conditions.

The gold-catalyzed synthesis of benzimidazoles from 2-nitroanilines and CO₂ in the presence of

 H₂ was reported, and a series of benzimidazoles were obtained under relatively mild conditions. 

Several supported Au catalysts including Au/TiO₂, Au/Al₂O₃, Au/ZnO, Au/polyurea and Au/hydrotalcite

 were examined for the synthesis of benzimidazole from the reaction of 2-nitroaniline with CO₂ and H₂, 

among which Au/TiO₂ displayed the best performance. The reaction mechanism was investigated, 

and it was found that the production of benzimidazole underwent the formation of o-phenylenediamine 

via the hydrogenation of 2-nitroaniline, followed by the cyclization of o-phenylenediamine with CO₂ and H₂. 

This work provides a CO₂-involved route for the synthesis of benzimidazoles, 

which may widen the applications of CO₂ in the chemical synthesis.

ORGANIC SPECTROSCOPY INTERNATIONAL: Ethyl 4-nitrobenzoate NMR

ORGANIC SPECTROSCOPY INTERNATIONAL: Ethyl 4-nitrobenzoate NMR:



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Natural sweeteners maple syrup, agave, and honey are complex mixtures with bioactive components that might confer health benefits

Pass the syrup! Maple syrup is a complex mixture of compounds, incuding bioactive components that might confer health benefits.
http://cen.acs.org/articles/92/i15/ACS-Meeting-News-Looking-Beyond.html

http://cen.acs.org/articles/92/i15/ACS-Meeting-News-Looking-Beyond.html

http://cen.acs.org/articles/92/i15/ACS-Meeting-News-Looking-Beyond.html

Maple syrup, agave, and honey are well-known for their roles as sweeteners. As such, their primary constituents are simple sugars such as sucrose and fructose. But scientists exploring the composition of these sweeteners are finding them to be surprisingly complicated.

These sweet mixtures contain many other classes of compounds, especially polyphenols, some of which may have bioactivity that imparts health benefits. Scientists hope to identify the beneficial compounds and eventually increase their concentration in sweeteners, so sweets can be more than just treats. Researchers described their latest findings in a symposium sponsored by the Division of Agricultural & Food Chemistry at the American Chemical Society national meeting held last month in Dallas.

Maple syrup is produced from sap of certain maple species, especially the sugar maple, Acer saccharum, which is native to eastern North America. Maple syrup is produced only in the U.S. and Canada, and about 80% of the world’s supply comes from Quebec.

Ethyl acetoacetate 乙酰乙酸乙酯 teaches you Organic spectroscopy... brush up?????

read at
http://orgspectroscopyint.blogspot.in/2014/04/ethyl-acetoacetate-teaches-you-organic.html

Ethyl 3-oxobutanoate
Acetoacetic acid ethyl ester
Ethyl acetylacetate
3-Oxobutanoic acid ethyl ester

Ethyl acetoacetate is produced industrially by treatment of diketene with ethanol.

The preparation of ethyl acetoacetate is a classic laboratory procedure.^[2] It is prepared via the Claisen condensation of ethyl acetate. Two moles of ethyl acetate condense to form one mole each of ethyl acetoacetate and ethanol.

Structure: 

IUPAC Name: ethyl 3-oxobutanoate (ethyl acetoacetate)

Analysis: C₆H₁₀O₃: MW = 130.14


The molecule contains an oxygen, and from the analysis, contains two double bonds, carbonyls or rings.
The mass spectrum displays a molecular ion and the base peak represents the formation of the acylium ion, indicating the presence of a methyl adjacent to a carbonyl. The presence of an m-45 peak strongly suggests the presence of an ethoxy group.
The ¹³C spectrum contains six peaks, indicating that all carbons are unique. The quartets at  14 and 24 represent relatively simple methyl groups; the triplets at  59 and 47 represent a CH₂ groups bonded to mildly electronegative groups; the singlets at  207 and 172 are in the carbonyl region, and most likely a ketone or aldehyde ( 207) and an ester ( 172).
The proton NMR shows evidence for an ethyl group and isolated CH₂ and CH₃ groups. The methylene of the ethyl group must be next to an electronegative atom (most likely oxygen) suggesting an -OCH₂CH₃ group. The isolated CH₂ must also be flanked by mildly electronegative groups, and the isolated CH₃ is in the region often observed for methyls adjacent to carbonyls.
The IR is consistent with a simple saturated hydrocarbon, possibly containing two carbonyls (based on the side peak at  1670 cm^-1). The minor peak at 3400 cm^-1 is too small to be an -OH.
The simplest structure which is consistent with all of these data would be a dicarbonyl compound containing an ethoxy residue and a methyl ketone (based on the presence of the acylium ion in the MS).
http://orgspectroscopyint.blogspot.in/2014/04/ethyl-acetoacetate-teaches-you-organic.html

......................

1H NMR

The proton NMR has a quartet coupled to a triplet, indicative of an ethyl group. The CH₂ must be adjacent to an electron withdrawing group since it is shifted to  4.1. The two singlets at  2.2 and 3.2 suggest isolated CH₂ and CH₃ groups and the CH₂ must be adjacent to one or more electronegative groups.

http://orgspectroscopyint.blogspot.in/2014/04/ethyl-acetoacetate-teaches-you-organic.html



http://orgspectroscopyint.blogspot.in/2014/04/ethyl-acetoacetate-teaches-you-organic.html
................................................................
13C NMR
¹³C NMR Assignments: 
¹³C NMR Data: q-13.6; q-24.2; t-59.2; t-46.6; s-172.0; s-207.1 
The ¹³C spectrum contains six peaks, indicating that all carbons are unique. The quartets at  14 and 24 represent relatively simple methyl groups; the triplets at  59 and 47 represent a CH₂ groups bonded to mildly electronegative groups; the singlets at  207 and 172 are in the carbonyl region, and most likely a ketone or aldehyde ( 207) and an ester ( 172).

ethyl acetoacetate CH3COCH2COOCH2CH3

http://orgspectroscopyint.blogspot.in/2014/04/ethyl-acetoacetate-teaches-you-organic.html

................................

MASS SPECTROSCOPY




Mass Spectrum Fragments: 
The mass spectrum consists of a molecular ion at 130, an m-15 peak at 115, which is consistent with loss of a CH₃ group, an m-43 peak (loss of acylium), an m-45 peak (loss of CH₃CH₂O-), and a base peak at m-43(m/e = 43) which suggests the formation of an acylium ion (CH₃-CO). The spectrum is consistent with a molecule which can lose methyl or ethoxy radicals, or can undergo fragmentation to form the acylium radical cation.


...............................

IR

3400-3200 cm^-1: no OH peak (too small) 3100 cm^-1: no significant peak, suggesting no unsaturated CH 2900 cm^-1: strong peak suggesting saturated CH 2200 cm^-1: no unsymmetrical triple bonds 1710 cm^-1: strong carbonyl with a second peak at 1670 cm^-1, suggesting a the possibility of two carbonyls 1600 cm^-1: no significant peaks, suggesting no carbon-carbon double bonds




http://orgspectroscopyint.blogspot.in/2014/04/ethyl-acetoacetate-teaches-you-organic.html




2D [1H,1H]-TOCSY




1D DEPT135





2D [1H,13C]-HSQC



2D [1H,13C]-HMBC





2D [1H,1H]-COSY


2D [1H,13C]-HMQC

http://orgspectroscopyint.blogspot.in/2014/04/ethyl-acetoacetate-teaches-you-organic.html

A solution to fluoronium riddle

The presence of a symmetrical fluoronium ion is confirmed by the 1:1 mixture of reaction products

The first evidence for hypervalent fluorine cations, or fluoronium ions, in solution has been found by US chemists. The research lays the foundations for characterising fluoronium ions – where the fluorine has two bonds and a formal positive charge – directly by spectroscopy and improving our understanding of fluorine’s interactions in organic chemistry

.http://www.rsc.org/chemistryworld/2013/04/fluoronium-ion-cation-chemists