This is a full account of our studies into the generation of highly functionalised 2-aryl-1,2-dihydropyridines and 2-methylene-3-aryl-1,2,3,4-tetrahydropyridines via intermolecular aryne ene reactions of Hantzsch esters. Furthermore, exposure to excess aryne revealed unusual 3′-aryl-spiro[benzocyclobutene-1,1′-(3′,4′-dihydropyridines)]. Mechanistic insights are provided by deuterium-labelling studies and DFT calculations, whilst preliminary cytotoxicity investigations reveal that the spirocycles are selective against colon carcinomas over ovarian cancer cell lines and that all the compounds have high selectivity indices with regards to non-cancer cells.
First day in the labs with our 1st year students. Today we will be doing acid-base titrations to determine the amount of citric acid in a sample of a powdered fruit drink. Students will use a standard solution of NaOH as a titrating agent and Phenolphthalein as indicator.
It is September again and as usual, we start the semester with the advanced practicals in chemistry with our Master students. It seems that after the summer break our students are in a very good mood and organic synthesis under nitrogen atmosphere becomes a balloon party!!!
The reaction of arynes with 1,4-dihydropyridines affords 2-aryl-1,2-dihydropyridines or 2-methylene-3-aryl-1,2,3,4-tetrahydropyridines via a regioselective C-2 or C-3 arylation. These compounds are the first series of isolable and bench-stable covalent ene adducts formed between dihydropyridines and unsaturated substrates. Experimental studies and DFT calculations provide mechanistic support for a concerted intermolecular aryne ene process, which may have implications for NAD(P)H model reactions.
It is again this time of the year, the semester has been very long. One more week of practicals and we are all ready for the Christmas break!!!
This year to honour the tradition we have our ChemisTree in the teaching labs. In this post I’m unveiling the secrets behind the colours of our 2016 ChemisTree.
Blue: A pinch of Copper (II) sulfate pentahydrate in water
Red: a few drops of Ferroin indicator in water
Green: A pinch of Nickel(II) nitrate hexahydrate in water
Deep purple: A pinch of potassium Permanganate in water
Violet: Literally 1 mg of Crystal Violet per Liter of water. Crystal Violet is a very strong dye.
Pink: A few drops of Phenolphthalein in a slightly basidified solution of NaOH in water. The colour fades away after a few minutes, long enough for a nice picture.
Many thanks to Indigo and Fosca for their help and creativity.
If this is not an amazing way to promote science I don’t know what it is. The Brazilian science magazine Superinteressante is developing a fighting video game using prominent scientists as the characters. Their abilities and fight skills are based in their scientific discoveries. You can take a look to the description of the characters in the website of his creator Diego Sanches. Imagine a fight between Tesla and and Stephen Hawking, I’m still in shock.
Take a look to this youtube demo: