Selective magnesiation of chloro-iodopurines: an efficient approach to new purine derivatives.
[reaction: see text] Both 6-chloro-2-iodo-9-isopropylpurine (1) and 2-chloro-6-iodo-9-benzylpurine (4) undergo a selective I/Mg exchange reaction with iPrMgCl at -80 degrees C. The reaction course at 0 degrees C is different. Magnesiation of 1 proceeds with the migration of magnesium to the 8 position of the purine nuclei. In the case of 4, substitution of iodine with an alkyl group from the Grignard reagent accompanied with a Cl/Mg exchange reaction takes place, and 6-alkyl-2-magnesiated purines (9) are formed. Thus prepared Grignard reagents afford the corresponding alcohols by the reaction with aldehydes.
Department of Organic Chemistry, Prague Institute of Chemical Technology, Technicka 5, 166 28 Prague 6, Czech Republic.
Tomas
T
Tobrman
Dalimil
D
Dvorak
D002384:Catalysis; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry*; D015394:Molecular Structure; D011687:Purines / Q000138:chemical synthesis*
D006846:Hydrocarbons, Halogenated; D011687:Purines; D008274:Magnesium