Dr Andrew L. Lawrence…..Excellent chemistry at work

Lawrence group reaction mechanism

 

http://www.chem.ed.ac.uk/staff/academic-staff/dr-andrew-l-lawrence

organic chemistry research group based at the School of Chemistry at the University of Edinburgh in Scotland.

Dr Andrew L. Lawrence

Dr Andrew L. Lawrence
Lecturer in Organic Chemistry
Room 217

University of Edinburgh
Joseph Black Building
David Brewster Road
Edinburgh
EH9 3FJ

0131 650 4831

Research Interests:
Total Synthesis of Natural Products, Biomimetic Chemistry, Domino Reactions

Our group does research in the area of natural product synthesis and the development of synthetic methodology. The aim of our research is to use nature as a source of inspiration and direction to improve and develop synthetic organic chemistry. Evolution has resulted in the highly efficient biosynthetic chemical pathways observed within living organisms. In our research we aim to harness the power of evolution by mimicking these chemical pathways.

This biomimetic approach to organic synthesis leads to a deeper understanding of how nature operates and illuminates the potential of new chemical reactions. Our biomimetic approach towards organic chemistry is primarily focused upon the synthesis of complex and biologically important natural products. When choosing our target natural products we are drawn to compounds that have extraordinary biosynthetic origins, complex molecular architectures and potent or novel biological/medicinal profiles.

Lawrence group reaction mechanism

We proposed that the unique and complex structure of the kingianin family of natural products was formed in nature through a spectacular radical cation formal Diels-Alder dimerization. We have recently completed a total synthesis of kingianins A, D and F in just ten steps following a strategy inspired by this biosynthetic speculation.

Lawrence research image

Certain phenylethanoid dimers and pseudo-dimers are assembled in nature through elegant sequences of nucleophilic addition reactions (Michael, aldol, Mannich reactions, etc.). We recently accomplished a total synthesis of incarvilleatone via a key biomimetic oxa-Michael/Michael/aldol reaction sequence.

Publications:

Total Synthesis and Structural Revision of the Alkaloid Incargranine B. Brown, P. D.; Willis, A. C.; Sherburn, M. S.; Lawrence, A. L.* Angew. Chem. Int. Ed. 201352, 13273-13275.

Total Synthesis of Kingianins A, D and F. Drew, S. L.; Sherburn, M. S.; Lawrence, A. L. Angew. Chem. Int. Ed. 2013, 52, 4221-4224.

Total Synthesis of Incarviditone and Incarvilleatone. Brown, P. D.; Willis, A. C.; Sherburn, M. S.; Lawrence, A. L.* Org. Lett. 2012, 14, 4537-4539.

University banner
Advertisement

Efficient synthesis of supported proline catalysts for asymmetric aldol reactions

Graphical abstract: Efficient synthesis of supported proline catalysts for asymmetric aldol reactions

Proline has been grafted onto silica supports in a single step by reacting trans-4-hydroxy-L-proline with chloropropyl tethers, without the use of protecting groups for the proline amine and carboxylic acid functional groups. The resulting catalysts have been characterised to show that grafting is through reaction with the 4-hydroxy group. The catalysts have been tested in an asymmetric aldol reaction, and shown to be both more active and more enantioselective than equivalent catalysts prepared using a protection/deprotection route for the proline grafting step.

http://pubs.rsc.org/en/Content/ArticleLanding/2014/CY/C4CY00970C?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2Fcy+%28RSC+-+Catalysis+Science+%26+Technology+latest+articles%29#!divAbstract

Efficient synthesis of supported proline catalysts for asymmetric aldol reactions
A. A. Elmekawy,a J. B. Sweeneya and D. R. Brown*a

*Corresponding authors
aDepartment of Chemical Sciences, University of Huddersfield, Huddersfield HD1 3DH, UK
E-mail: d.r.brown@hud.ac.uk;
Fax: +44 (0)1484 472182 ;
Tel: +44 (0)1484 47339
Catal. Sci. Technol., 2014, Advance Article
DOI: 10.1039/C4CY00970C

Azaheterocycles Made Easy

thumbnail image: Azaheterocycles Made Easy

Azaheterocycles Made Easy
Flexible route makes azaheterocycles easier to access

 

Azaheterocycles are a highly important class of compounds due to their biological activities and pharmaceutical applications. In particular, dihydroazepines, dihydropyrroles, and pyrroles are constituents of a valuable privileged structure in organic chemistry.

Read more

 

http://www.chemistryviews.org/details/ezine/6508611/Azaheterocycles_Made_Easy.html

Going for Gold in Chiral Amine Synthesis

thumbnail image: Going for Gold in Chiral Amine Synthesis

Going for Gold in Chiral Amine Synthesis
A diphosphine binuclear gold(I) chloride complex catalyzes the asymmetric hydroamination of alkenes

Amines are synthesized most effectively by hydroamination of unactivated alkenes, the enantioselective version of which is best achieved by metal catalysis. Binuclear gold(I) complexes can catalyze the hydroamination of alkenes, however, the harsh and stringent reactions conditions required have prevented full development of this metal for synthesis of chiral amines. In addition, the exact catalytic species involved and whether the activating silver salt participates haChiral Amine Synthesis remained a mystery.

Read more

http://www.chemistryviews.org/details/ezine/6518601/Going_for_Gold_in_Chiral_Amine_Synthesis.html

Directing Venom To Fight Cancer ACS Meeting News: Encapsulated venom peptide can skip healthy cells

09233-notw11-scorpioncxd

 
Scorpion toxins may one day be useful as anticancer drugs.
Credit: Courtesy of Dipanjan Pan

Venom from scorpions or honeybees sounds like it wouldn’t do a person much good. But by directing a modified component just to tumors, researchers might leverage it into a drug.

Peptides in some venoms bind to cancer cells and block tumor growth and spread. But they have not yet been developed successfully as anticancer agents because they attack healthy cells too.

Bioengineer Dipanjan Pan and coworkers at the University of Illinois, Urbana-Champaign, are now using polymeric nanoparticles to deliver venom toxin directly to cancer cells.

read at

http://cen.acs.org/articles/92/i33/Directing-Venom-Fight-Cancer.html

 

 

 

 

 

Seeds Sprout Select Nanotubes Nanotechnology: Chemists create just one type of single-walled carbon nanotube from polycyclic precursor

09232-notw1-nanotubesbluecxd

A polycyclic aromatic hydrocarbon seed folds up into a cap when heated on a platinum surface. This cap dictates the chirality of the nanotube, approximately 2 nm in diameter, that grows from it.
Credit: Juan Ramon Sanchez-Valencia

Seeds Sprout Select Nanotubes

Nanotechnology: Chemists create just one type of single-walled carbon nanotube from polycyclic precursor
Using a 96-carbon polycyclic aromatic molecule as a seed, chemists have managed to make single-walled carbon nanotubes (SWNTs) of just one type—a long-sought goal in nanotechnology. Being able to make nanotubes of a specific type should help scientists better exploit their promising electronic properties.  read at……………………..

Creating Cucurbiturils Synthetic route to prepare cucurbiturils substituted at the bridge position has been developed

thumbnail image: Creating Cucurbiturils

Creating Cucurbiturils
Synthetic route to prepare cucurbiturils substituted at the bridge position has been developed
Read more

http://www.chemistryviews.org/details/news/6104831/Creating_Cucurbiturils.html

New Short Strategy for the Synthesis of the Dibenz[b,f]oxepin Scaffold

abstract graphic

David R. R. Moreno 1, Giorgio Giorgi 2, Cristian O. Salas 1 and Ricardo A. Tapia 1,*
1 Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de
Chile, Santiago 7820436, Chile; E-Mails: drmoreno@uc.cl (D.R.R.M.); cosalas@uc.cl (C.O.S.)

chile flag
2 Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia,
Universidad Complutense, Madrid 28040, Spain;E-Mail: giorgiogiorgi@farm.ucm.es

spain flag

* Author to whom correspondence should be addressed; E-Mail: rtapia@uc.cl;
Tel.: +56-2-2354-4429; Fax: +56-2-2354-4744.

Molecules 201318(12), 14797-14806; doi:10.3390/molecules181214797
Links

Download PDF Full-text (257 KB) |  Supplementary Files

(This article belongs to the Section Organic Synthesis)
 In this report a short and efficient synthesis of the dibenz[b,f]oxepin framework through intramolecular SNAr and McMurry reactions is described. The diaryl ethers required for the McMurry reaction have been obtained in good yields under microwave-assisted conditions of the reaction of salicylaldehydes with fluorobenzaldehydes without catalysts. Application of an intramolecular McMurry reaction to the synthesized diarylethers using TiCl4/Zn in THF gave the target dibenzo[b,f]oxepin system in 53%–55% yields.
Molecules 2013, 18, 14797-14806; doi:10.3390/molecules181214797

In conclusion, we have developed a short synthesis of dibenzo[b,f]oxepin derivatives using SNAr
and intramolecular McMurry reactions. An efficient process to obtain diarylethers through SNAr
reaction of salicylaldehydes with fluorobenzaldehydes using microwave irradiation is described.
McMurry reaction of diarylethers using TiCl4 and Zn in THF afforded the target tricyclic system in
reasonable yields (53%–55%). Further work on the synthesis of natural and pharmacologically active
dibenzo[b,f]oxepins are under way.

abstract graphic

 

Links

Download PDF Full-text (257 KB) | Download

Links

Supplementary Files   DOWNLOAD

ONE EXAMPLE SEE BELOW

compd 5a

R=H

Dibenz[b,f]oxepin (5a).

Stilbene 3 (215 mg, 0.5 mmol) was added to a solution of KOH (900 mg,
16 mmol) in a mixture of EtOH (15 mL) and H2O (15 mL) and the suspension was heated under reflux
for 1 h. After cooling, the reaction mixture was acidified with aqueous HCl (10%) to pH 4 and
extracted with CH2Cl2 (3 × 25 mL). The combined organic extracts were washed with saturated
aqueous NaHCO3, dried, and filtered through a short column of silica gel. After the removal of the
solvent, the residue was dissolved in DMSO (5.0 mL) and Cs2CO3 (651.6 mg, 2.0 mmol) was added.
The reaction mixture was heated in a microwave reactor at 180 °C for 15 min. After cooling, the
solvent was evaporated under reduced pressure and the crude product was purified by flash column
chromatography (silica gel, EtOAc-hexanes; 1:9) to afford 5a (70 mg, 72%),

mp 108.5–109.5 °C
(Lit. 106–108 °C [34], 110–111 °C [35]).

IR (KBr): 􀟥􀷤 max 3069, 3044, 1483, 798 cm−1.
1H-NMR (acetone-d6) δ 6.82 (s, 2H, Two protons of -CH=CH- ), 7,19 (t, J = 7,8 Hz, 2H), 7.25 (d, J = 7.8 Hz, 2H), 7.30 (d, J = 7.8 Hz,2H), 7.38 (t, J = 7.8 Hz, 2H).

13C-NMR (acetone-d6) δ 122.9, 126.6, 131.1, 131.6, 131.7, 132.3, 159.1.

The Mapuche people were the original inhabitants of southern and central Chile.

Fighting during the War of the Pacific: The Battle of Iquique on 21 May 1879.

Parinacota volcano in northern Chile

Araucanian Indians and Huasos in Chile, 19th century

The Catholic Monarchs in the Capitulation of Granada, the end of the Reconquista and the unification of the kingdoms forming actual Spain.

ANTHONY MELVIN CRASTO

THANKS AND REGARD’S
DR ANTHONY MELVIN CRASTO Ph.D

GLENMARK SCIENTIST , NAVIMUMBAI, INDIA

did you feel happy, a head to toe paralysed man’s soul in action for you round the clock

need help, email or call me

MOBILE-+91 9323115463
web link

I was  paralysed in dec2007, Posts dedicated to my family, my organisation Glenmark, Your readership keeps me going and brings smiles to my family

 

 

om  animation

Oxindole as starting material in organic synthesis

Oxindole as starting material in organic synthesis (13-8074LR)

Arkivoc 2013 Part (i): Special Issue ‘Reviews and Accounts’ [pp. 470-535]


Full Text: PDF (1,621K)

http://www.arkat-usa.org/get-file/48468/    ,,,,,,,,,,,,,,,,,,,,,,free access

Ghodsi Mohammadi Ziarani,a* Parisa Gholamzadeh,aNegar Lashgari,a,b and Parvin Hajiabbasia

a  Department_of_ChemistryAlzahra University, Vanak Square, P.O. Box 1993891176,
Tehran, Iran
b  School of Chemistry, College of Science, University of Tehran, P.O. Box 14155-6455,
Tehran, Iran

Abstract
This review highlights the advances in the use of oxindole as starting material in the synthesis of
various organic compounds and drugs. The reactions can be performed on different reactive sites of
oxindole which are the carbonyl group, C-3 site, nitrogen atom, and aromatic ring. In addition, the
roles of oxindole in one-pot and domino reactions are discussed.

Persian miniature depicting Timur‘s campaign in India

File:4758976353 tehran b.jpg
teheran at night
Ayatollah Khomeini returns to Iran after 14 years exile on February 1, 1979.
AUTHORS
Reza Smizadeh