Wednesday, November 05, 2008

What is Click Chemistry?

2001 was a big year for K.B. Sharpless. He received the coveted Nobel Prize in Chemistry and introduced the concept Click Chemistry. I had the great pleasure of meeting him in 2001 and his lecture on Click Chemistry completely changed the way I think about chemistry.
I do not do Click Chemistry or even Click Reactions but I like the overall concept and I fulfil about half of the Click Chemistry commandments in my daily research.
Most chemists have no idea what Click Chemistry really is and think making a triazole makes you a Click Chemist. This is incorrect and many papers are published with Click Chemistry in the title even though it isn't Click Chemistry! Click Chemistry is not a specific reaction it is a concept. Here's a condensed version of rules you have to fulfil to become a Click Chemist.:
The reaction must be:
(1) modular
(2) wide in scope
(3) give very high yields
(4) generate only inoffensive byproducts
(5) stereopecific
The process must be:
(6) simple reaction conditions
(7) readily available starting materials and reagents
(8) use no solvent or a solvent that is benign or easily removed
(9) simple product isolation by non-chromatographic methods
Sharpless published an excellent paper introducing the concept
Click Chemistry: Diverse Chemical Function from a Few Good Reactions, H.C. Kolb, M.G. Finn and K.B. Sharpless, Angew. Chem. Int. Ed., 2001, 40, pp. 2004-2021.

Tuesday, November 04, 2008

Curly Arrow - Established 18th October 2006

Curly Arrow has now been in business for two years. Things have been a bit random the last year primarily due to shifting between jobs and continents. Let's hope things will become a bit more structured in the coming year. Thanks to all bloggers for comments, endless enthusiasm and emails.
The year 2006-2007 all the top 10 visitors were from the US or UK. This year things are a bit different with Australia and Canada making an entry at 5th and 7th place and the first company (GSK) has made it on the list at 8th place. D!
From 9 November 2007 to 4th November 2008
Absolute unique visitors: 21,250 (previous year 13,369)
Total visits: 37,513 (103 Visits/Day) [previous year 34,820 (89.47 Visits/Day)]
Average time on site: 1:28 minute (previous year 1:06 minute)
The 10 most frequent visitors identifiable:
(1) Princeton University (last year: Scripps Research Institute)
(2) Scripps Research Institute (last year: University of Cambridge)
(3) Oxford University (last year: Oxford University)
(4) University of Cambridge (last year: University of California)
(5) Flinders University (last year: Princeton University)
(6) State University of New York at Buffalo (last year: Columbia University)
(7) Carleton University (last year: University of Rochester)
(8) GlaxoSmithKline (last year: Harvard University)
(9) University of California Santa Barbara (last year: Pennsylvania State University)
(10) University of California Irvine (last year: North Dakota State University)