959615-64-6Relevant articles and documents
A one-pot diazotation-fluorodediazoniation reaction and fluorine gas for the production of fluoronaphthyridines
Abele, Stefan,Schmidt, Gunther,Fleming, Matthew J.,Steiner, Heinz
, p. 993 - 1001 (2014/10/15)
Several synthetic routes to 7-fluoro-2-methoxy-8-methyl-1,5-naphthyridine (1) are presented, and their suitability for scale-up is discussed. The way of introducing the fluorine atom is crucial. Early routes start from commercially available fluorinated building blocks or employ F+ reagents like SelectFluor and delivered up to 70 kg of 7-fluoro-2-methoxy-1,5-naphthyridine (18). To prepare for larger scales, the focus turned to the use of HF or elemental fluorine, both one of the cheapest sources of fluorine. The first method, a one-pot diazotation-fluorodediazoniation with 6-methoxy-1,5- naphthyridin-3-amine (9) in HF gave the fluorinated naphthyridine 18 in high yield and purity without isolation of the unstable diazonium salt, the latter being a severe drawback of the related Balz-Schiemann protocol. The second method relies on the use of fluorine gas for a surprisingly selective ortho-fluorination of 6-methoxy-1,5-naphthyridin-4-ol (10).
Benzimidazoles: Novel mycobacterial gyrase inhibitors from scaffold morphing
Hameed P, Shahul,Raichurkar, Anandkumar,Madhavapeddi, Prashanti,Menasinakai, Sreenivasaiah,Sharma, Sreevalli,Kaur, Parvinder,Nandishaiah, Radha,Panduga, Vijender,Reddy, Jitendar,Sambandamurthy, Vasan K.,Sriram
supporting information, p. 820 - 825 (2014/08/05)
Type II topoisomerases are well conserved across the bacterial species, and inhibition of DNA gyrase by fluoroquinolones has provided an attractive option for treatment of tuberculosis (TB). However, the emergence of fluoroquinolone-resistant strains of Mycobacterium tuberculosis (Mtb) poses a threat for its sustainability. A scaffold hopping approach using the binding mode of novel bacterial topoisomerase inhibitors (NBTIs) led to the identification of a novel class of benzimidazoles as DNA gyrase inhibitors with potent anti-TB activity. Docking of benzimidazoles to a NBTI bound crystal structure suggested that this class of compound makes key contacts in the enzyme active site similar to the reported NBTIs. This observation was further confirmed through the measurement of DNA gyrase inhibition, and activity against Mtb strains harboring mutations that confer resistance to aminopiperidines based NBTIs and Mtb strains resistant to moxifloxacin. Structure-activity relationship modification at the C-7 position of the left-hand side ring provided further avenue to improve hERG selectivity for this chemical series that has been the major challenges for NBTIs.