Lime juice as an efficient and green catalyst for the synthesis of 6-amino-4- aryl-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile derivatives

Vol 6, No 1, Feb.2014
……….

PDF

http://www.iranjoc.com/upfiles/Journals/vol6no1/j77a241.pdf

Iranian Journal of Organic Chemistry Vol. 6, No. 1 (2014) 1187-1192

Mehrnoosh kangania, Nourallah Hazeria*, Khatereh Khandan-Baranib, Mojtaba Lashkaric, and MalekTaher Maghsoodloua
aDepartment of Chemistry, University of Sistan and Baluchestan, P.O. Box 98135 – 674, Zahedan, Iran.
bDepartment of chemistry, Zahedan Branch, Islamic Azad University, Zahedan, Iran.
cFaculty of Sciences, Najafabad Branch, Islamic Azad University, Najafabad, Esfahan, Iran

www.iranjoc.com upfiles Journals vol6no1 j77a241.pdf

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Facile Synthesis of Bis(indolyl)methanes Catalyzed by α-Chymotrypsin

Green Chemistry International

abstract graphic

Molecules2014, 19(12), 19665-19677; doi:10.3390/molecules191219665

A mild and efficient method catalyzed by α-chymotrypsin was developed for the synthesis of bis(indolyl)methanes through a cascade process between indole and aromatic aldehydes. In the ethanol aqueous solution, a green medium, a wide range of aromatic aldehydes could react with indole to afford the desired products with moderate to good yields (from 68% to 95%) using a little α-chymotrypsin as catalyst.

Molecules2014, 19(12), 19665-19677; doi:10.3390/molecules191219665

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CMI 977, LDP 977

New Drug Approvals

CMI 977

C16-H19-F-N2-O4
322.3341
Millennium (Originator), Taisho (Licensee)

(2S,5S)-1-[4-[5-(4-Fluorophenoxymethyl)tetrahydrofuran-2-yl]-3-butynyl]-1-hydroxyurea 175212-04-1 CMI-977 is a potent 5-lipoxygenase inhibitor that intervenes in the production of leukotrienes and is presently being developed for the treatment of chronic asthma. It is a single enantiomer with an alltrans (2S,5S) configuration. Of the four isomers of CMI-977, the S,Sisomer was found to have the best biological activity and was selected for further development. The enantiomerically pure product was synthesized on a 2-kg scale from (S)-(+)-hydroxymethyl-γ-butyrolactone.

CytoMed, Inc. announced y the initiation of Phase I clinical trials for CMI-977, its orally active therapeutic product for the treatment of asthma. CMI-977 inhibits the 5-lipoxygenase (5-LO) cellular inflammation pathway to block the generation of leukotrienes, which play a key role in triggering bronchial asthma. The Company also announced that it has received a U.S. patent covering a number of…

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Conversion of carbonyl compounds to alkynes: general overview and recent developments

Graphical abstract: Conversion of carbonyl compounds to alkynes: general overview and recent developments

The preparation of alkynes from carbonyl compounds via a one-carbon homologation has become a very useful pathway for the synthesis of acetylenic compounds, both internal and terminal. This tutorial review provides an overview of the different methods available for this transformation, including their scope and limitations, recent developments and applications in total syntheses.

Conversion of carbonyl compounds to alkynes: general overview and recent developments

*Corresponding authors
aLaboratory of Organic Chemistry, Aalto University School of Science and Technology, FIN-00076 Aalto, Finland
E-mail: ari.koskinen@tkk.fi;
Fax: +358-9-470 22538 ;
Tel: +358-9-470 22526
Chem. Soc. Rev., 2010,39, 2007-2017

DOI: 10.1039/B915418C

http://pubs.rsc.org/en/content/articlelanding/2010/cs/b915418c#!divAbstract

Seyferth-Gilbert Alkyne Synthesis

Seyferth-Gilbert Alkyne Synthesis

The Seyferth–Gilbert homologation is a chemical reaction of an aryl ketone 1 (or aldehyde) with dimethyl (diazomethyl)phosphonate 2 and potassium tert-butoxide to give substituted alkynes 3.[1][2] Dimethyl (diazomethyl)phosphonate 2 is often called the Seyferth–Gilbert reagent.[3]

Aldehydes and ketones can be converted into alkynes with one carbon homologation using the α-diazophosphonate compound called the Gilbert reagent.

When Y=H, the reaction needs a strong base such as tBuOK to proceed and base sensitive reactants are inevitably incompatible. However, with the modified reagent in which Y=Ac, milder bases such as potassium carbonate can be used, so the substrate scope is wider (the Ohira-Bestmann modification).

The Seyferth–Gilbert homologation

This reaction is called a homologation because the product has exactly one additional carbon more than the starting material.

Reaction mechanism

Deprotonation of the Seyferth–Gilbert reagent A gives an anion B, which reacts with the ketone to form the oxaphosphetane D. Elimination of dimethylphosphate E gives the vinyldiazo-intermediate Fa and Fb. The generation of nitrogen gas gives a vinyl carbene G, which via a 1,2-migration forms the desired alkyne H.

The mechanism of the Seyferth–Gilbert homologation
gilbert_alkyne_2.gif

Bestmann modification

Ohira–Bestmann reagent
Ohira-bestmann reagent 2d-skeletal.png
Identifiers
CAS number 90965-06-3
PubChem 11106189
ChemSpider 9281325
Jmol-3D images Image 1
Properties
Molecular formula C5H9N2O4P
Molar mass 192.11
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Dimethyl (diazomethyl)phosphonate can be generated in situ from dimethyl-1-diazo-2-oxopropylphosphonate (also called the Ohira-Bestmann reagent) by reaction with methanol and potassium carbonate. Reaction of Bestmann’s reagent with aldehydes gives terminal alkynes often in very high yield.[4][5]

Bestmann's reagent

The use of the milder potassium carbonate makes this procedure much more compatible with a wide variety of functional groups.

Improved in situ generation of the Ohira-Bestmann reagent

Safe and scalable synthesis of alkynes from aldehydes

Recently a safer and more scalable approach has been developed for the synthesis of alkynes from aldehydes. This protocol takes advantage of a stable sulfonyl azide, rather than tosyl azide, for the in situ generation of the Ohira−Bestmann reagent.[6]

Another modification for less reactive aldehydes is made by replacement of potassium carbonate with caesium carbonate in MeOH and results in a drastic yield increase.[7]

  • Examples

Lithiated TMS diazomethane also works for the same transformation.[1] Shown below is an example where it is used in the synthesis of (+)-Ambruticin.[2]

gilbert_alkyne_3.gif

An example in the context of bryostatin synthesis.[3]

gilbert_alkyne_4.gif

References

  1.  D. Seyferth, R. S. Marmor and P. Hilbert (1971). “Reactions of dimethylphosphono-substituted diazoalkanes. (MeO)2P(O)CR transfer to olefins and 1,3-dipolar additions of (MeO)2P(O)C(N2)R”. J. Org. Chem. 36 (10): 1379–1386. doi:10.1021/jo00809a014.
  2. J. C. Gilbert and U. Weerasooriya (1982). “Diazoethenes: their attempted synthesis from aldehydes and aromatic ketones by way of the Horner-Emmons modification of the Wittig reaction. A facile synthesis of alkynes”. J. Org. Chem. 47 (10): 1837–1845.doi:10.1021/jo00349a007.
  3.  D. G. Brown, E. J. Velthuisen, J. R. Commerford, R. G. Brisbois and T. H. Hoye (1996). “A Convenient Synthesis of Dimethyl (Diazomethyl)phosphonate (Seyferth/Gilbert Reagent)”. J. Org. Chem. 61 (7): 2540–2541. doi:10.1021/jo951944n.
  4.  S. Müller, B. Liepold, G. Roth and H. J. Bestmann* (1996). “An Improved One-potProcedure for the Synthesis of Alkynes from Aldehydes”. Synlett 1996 (06): 521–522.doi:10.1055/s-1996-5474.
    1. 5  G. Roth, B. Liepold, S. Müller and H. J. Bestmann (2004). “Further Improvements of the Synthesis of Alkynes from Aldehydes”. Synthesis 2004 (1): 59–62. doi:10.1055/s-2003-44346.
    2. 6   Jepsen, T.H, Kristensen, J.L. J. Org. Chem. 2014, “In Situ Generation of the Ohira–Bestmann Reagent from Stable Sulfonyl Azide: Scalable Synthesis of Alkynes from Aldehydes”. http://pubs.acs.org/doi/abs/10.1021/jo501803f
    3.  7    Lidija Bondarenko, Ina Dix, Heino Hinrichs, Henning Hopf* (2004). “Cyclophanes. Part LII:1 Ethynyl[2.2]paracyclophanes – New Building Blocks for Molecular Scaffolding”.Synthesis 2004 (16): 2751–2759. doi:10.1055/s-2004-834872.
  • General References

・Seyferth, D.; Hilbert, P.; Marmor, R. S. J. Am. Chem. Soc. 1967, 89, 4811; J. Org. Chem. 1971, 36, 1379. doi:10.1021/jo00809a014
・Gilbert, J. C.; Weerasooriya, U. J. Org. Chem. 1979, 44, 4997; ibid. 1982, 47, 1837. doi:10.1021/jo00349a007

<Ohira-Bestmann Modification>
・Ohira, S. Synth. Commun. 1989, 19, 561.
・Müller, S.; Liepold, B.; Roth, G. J.; Bestmann, H. J. Synlett 1996, 521. doi:10.1055/s-1996-5474
・Roth, G. J.; Liepold, B.; Muller, S. G.; Bestmann, H. J. Synthesis 2004, 59. doi:10.1055/s-2003-44346

<Preparation>
・Callant, P.; D’haenens, L.; Vandewalle, M. Synth. Commun. 1984, 14, 155.
・Brown, D. G.; Velthuisen, E. J.; Commerford, J. R.; Brisbois, R. G.; Hoye, T. R. J. Org. Chem. 1996, 61, 2540. doi:10.1021/jo951944n

Many Little Pieces That Shan’t – Poem (after tragic tragic murder of kids in Pakistan)

Darshana Varia Nadkarni's Blog

I can only imagine the deep deep anguish of parents of the children who lost their lives to terrorists in Pakistan.
Here’s a poem dedicated to the parents, for whom the pain will live forever.

A mother looks over her 15-year-old son Mohammed Ali Khan, who was killed by the Taliban gunmen

Many Little Pieces That Shan’t

My child, my heart has broken into many little pieces
In tiny pieces, it’s torn with fury, sadness, numbness

To give warmth, one piece will lie beside you
Six feet under cold cruel earth, always loving you

One will fly heavenward, with you in tandem
I am mother not by chance, it’s not  random

One shall go to demand justice, to HELL
My bleeding heart will go with the evil

In one small piece of my heart, I will try to fill
All your love and then will make time stand still

What I won’t do is pick up the pieces, I just can’t
My heart’s broken into many little…

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ORGANIC SPECTROSCOPY INTERNATIONAL……A blog to brush up spectroscopy fundamentals