Imidazopyridine and pyrimidinopyridine systems from perfluorinated pyridine derivatives

N-{3-[2-(4-Fluorophenoxy)ethyl]-2,4-dioxo-1,3-diazaspiro[4.5]decan-7-yl}-4-methoxybenzenesulfonamide

In the title compound, C₂₃H₂₆FN₃O₆S, the two terminal aromatic rings form a dihedral angle of 49.26 (12)°. The cyclo­hexane ring adopts a chair conformation and the five-membered ring is essentially planar, with a maximum deviation from planarity of 0.0456 (19) Å. The dihedral angles between the five-membered ring and the meth­oxy­benzene and fluoro­benzene rings are 33.56 (11) and 81.94 (12)°, respectively. The crystal structure displays N—H⋯O hydrogen bonds as well as weak inter­molecular C—H⋯O inter­actions.

N-[3-(4-Fluorobenzyl)-2,4-dioxo-1,3-diazaspiro[4.5]dec-8-yl]-2-methylbenzenesulfonamide

In the title compound, C₂₂H₂₄FN₃O₄S, the cyclo­hexane ring adopts a chair conformation and the five-membered ring is essentially planar, with a maximum deviation of 0.040 (2) Å. The dihedral angles between the five-membered ring and the tolyl and fluoro­benzene rings are 56.74 (12) and 89.88 (12)°, respectively. The two terminal benzene rings make a dihedral angle of 63.53 (12)°. The crystal structure displays inter­molecular C—H⋯O and N—H⋯O hydrogen bonds. An intra­molecular C—H⋯O hydrogen bond also occurs.

A Convenient, TiCl 4 /SnCl 4 -Mediated Synthesis of N-Phenyl or N-Aryl Benzamidines and N-Phenylpicolinamidines

A new, TiCl4-or SnCl4-mediated, solvent-free method was developed for the synthesis of N-Aryl benzamidines and N-phenylpicolinamidines, in moderate-to-good yield, using suitable amines and nitriles as starting materials.

9,10-Dioxa-1,2-diaza-anthracene derivatives from tetrafluoropyridazine

Reaction of tetrafluoropyridazine with catechol gives a tricyclic 9,10-dioxa-1,2-diaza-anthracene system by a sequential nucleophilic aromatic substitution ring annelation process, further extending the use of perfluoroheteroaromatic derivatives for the synthesis of unusual polyfunctional heterocyclic architectures. The tricyclic scaffold reacts with amines and sodium ethoxide providing a short series of functional 9,10-dioxa-1,2-diaza-anthracene systems.

Perhalogenated pyrimidine scaffolds. Reactions of 5-chloro-2,4,6-trifluoropyrimidine with nitrogen centred nucleophiles

BACKGROUND

Highly functionalised pyrimidine derivatives are of great importance to the life-science industries and there exists a need for efficient synthetic methodology that allows the synthesis of polysubstituted pyrimidine derivatives that are regioselective in all stages to meet the demands of RAS techniques for applications in parallel synthesis. 5-Chloro-2,4,6-trifluoropyrimidine may be used as a scaffold for the synthesis of polyfunctional pyrimidine systems if sequential nucleophilic aromatic substitution processes are regioselective.

RESULTS

Use of 5-chloro-2,4,6-trifluoropyrimidine as a core scaffold for the synthesis of functionalised pyrimidine systems is assessed in reactions with a small range of nitrogen centred nucleophiles. Mixtures of products arising from nucleophilic aromatic substitution processes are formed, reflecting the activating effect of ring nitrogen and the steric influences of the chlorine atom.

CONCLUSIONS

5-Chloro-2,4,6-trifluoropyrimidine is not an ideal scaffold for analogue synthesis or for multiple substitution processes because purification must be performed to remove the 2-substituted regioisomer from the mixture before further reactions can be carried out. However, 4-amino derivatives can be isolated in acceptable yields using this methodology.