- A one-pot diazotation-fluorodediazoniation reaction and fluorine gas for the production of fluoronaphthyridines
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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).
- Abele, Stefan,Schmidt, Gunther,Fleming, Matthew J.,Steiner, Heinz
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p. 993 - 1001
(2014/10/15)
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- Novel N-linked aminopiperidine-based gyrase inhibitors with improved hERG and in vivo efficacy against mycobacterium tuberculosis
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DNA gyrase is a clinically validated target for developing drugs against Mycobacterium tuberculosis (Mtb). Despite the promise of fluoroquinolones (FQs) as anti-tuberculosis drugs, the prevalence of pre-existing resistance to FQs is likely to restrict their clinical value. We describe a novel class of N-linked aminopiperidinyl alkyl quinolones and naphthyridones that kills Mtb by inhibiting the DNA gyrase activity. The mechanism of inhibition of DNA gyrase was distinct from the fluoroquinolones, as shown by their ability to inhibit the growth of fluoroquinolone-resistant Mtb. Biochemical studies demonstrated this class to exert its action via single-strand cleavage rather than double-strand cleavage, as seen with fluoroquinolones. The compounds are highly bactericidal against extracellular as well as intracellular Mtb. Lead optimization resulted in the identification of potent compounds with improved oral bioavailability and reduced cardiac ion channel liability. Compounds from this series are efficacious in various murine models of tuberculosis.
- Hameed P, Shahul,Patil, Vikas,Solapure, Suresh,Sharma, Umender,Madhavapeddi, Prashanti,Raichurkar, Anandkumar,Chinnapattu, Murugan,Manjrekar, Praveena,Shanbhag, Gajanan,Puttur, Jayashree,Shinde, Vikas,Menasinakai, Sreenivasaiah,Rudrapatana, Suresh,Achar, Vijayashree,Awasthy, Disha,Nandishaiah, Radha,Humnabadkar, Vaishali,Ghosh, Anirban,Narayan, Chandan,Ramya,Kaur, Parvinder,Sharma, Sreevalli,Werngren, Jim,Hoffner, Sven,Panduga, Vijender,Kumar, C. N. Naveen,Reddy, Jitendar,Kumar Kn, Mahesh,Ganguly, Samit,Bharath, Sowmya,Bheemarao, Ugarkar,Mukherjee, Kakoli,Arora, Uma,Gaonkar, Sheshagiri,Coulson, Michelle,Waterson, David,Sambandamurthy, Vasan K.,De Sousa, Sunita M.
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supporting information
p. 4889 - 4905
(2014/07/07)
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- Benzimidazoles: Novel mycobacterial gyrase inhibitors from scaffold morphing
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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.
- Hameed P, Shahul,Raichurkar, Anandkumar,Madhavapeddi, Prashanti,Menasinakai, Sreenivasaiah,Sharma, Sreevalli,Kaur, Parvinder,Nandishaiah, Radha,Panduga, Vijender,Reddy, Jitendar,Sambandamurthy, Vasan K.,Sriram
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supporting information
p. 820 - 825
(2014/08/05)
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- NOVEL HETEROCYCLIC COMPOUND OR SALT THEREOF AND INTERMEDIATE THEREOF
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Disclosed is a compound represented by the general formula: [wherein R1 represents an aryl or heterocyclic group which may be substituted or the like; X1 represents a C2-C4 alkylene group or the like; X2, X3 and X5 independently represent NH, a bond or the like; X4 represents a lower alkylene group, a bond or the like; Y1 represents a bivalent alicyclic hydrocarbon residue which may be substituted or a bivalent alicyclic amine residue which may be substituted; and Z1, Z2, Z3, Z4, Z5 and Z6 independently represent a nitrogen atom, a group represented by the formula: CH, or the like, provided that at least one of Z3, Z4, Z5 and Z6 represents a nitrogen atom] or a salt thereof, which is useful as an antibacterial agent.
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