- NOVEL PROCESS AND INTERMEDIATES
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The present invention relates to a process for the preparation of steroidal 17β-carboxylic thioates. More particularly the present invention relates to a convenient and efficient synthesis of steroidal 17β-carboxylic thioates, such as fluticasone propionate I, using soluble mixed fluorides to introduce fluorine by displacing an appropriate leaving group X in compounds II resulting in selective and controlled fluorination. The present invention also relates to intermediates II and their preparation.
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Page/Page column 12
(2009/07/18)
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- NOVEL PROCESS AND INTERMEDIATES
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The present invention relates to a process for the preparation of steroidal 17β-carboxylic thioates. More particularly the present invention relates to a convenient and efficient synthesis of steroidal 17β-carboxylic thioates, such as fluticasone propionate formula (I), using soluble mixed fluorides to introduce fluorine by displacing an appropriate leaving group X in compounds formula (II) resulting in selective and controlled fluorination. The present invention also relates to intermediates formula (II) and their preparation.
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Page/Page column 23; 30
(2008/06/13)
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- Automated radiosynthesis of no-carrier-added [S-fluoromethyl-18F] fluticasone propionate as a radiotracer for lung deposition studies with PET
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Fluticasone propionate [(S)-fluoromethyl-6α,9α-difluoro-11β-hydroxy-16α-methyl-3-oxo-17α -(propionyloxy)-androsta-1,4-diene-17β-carbothioate; FP] is a potent anti-inflammatory steroid with several therapeutic indications, including use as an anti-asthmatic drug when administered as sized particles by inhalation from a pressurised metered-dose inhaler (pMDI). FP was successfully labelled with fluorine-18 (t( 1/4 ) = 109.6 min: β+ = 100%) by displacement of tosylate with cyclotron-produced no-carrier-added [18F]fluoride in an (S)-tosylmethyl precursor prepared from the known (S)-chloromethyl analogue of FP. Radiochemically pure [S-/fluoromethyl-18]FP was separated by reverse phase HPLC in 35% radiochemical yield (decay-corrected) within 80 min from the end of radionuclide production (as verified by, radio-HPLC, LC-MS and LC-NMR). The radiosynthesis was automated for the safe production of high radioactivities (20-50 mCi) of [18F]FP in a lead-shielded hot-cell for subsequent incorporation into formulated FP particles within a pMDI and subsequent study of FP deposition in human lung using positron emission tomography (PET).
- Aigbirhio, Franklin I.,Carr, Richard M.,Pike, Victor W.,Steel, Colin J.,Sutherland, Derek R.
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p. 567 - 584
(2007/10/03)
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- Synthesis and structure-activity relationships in a series of antiinflammatory corticosteroid analogues, halomethyl androstane-17β- carbothioates and -17β-carboselenoates
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The preparation and topical antiinflammatory potencies of a series of halomethyl 17α-(acyloxy)-11β-hydroxy-3-oxoandrosta-1,4-diene-17β- carbothioates, carrying combinations of 6α-fluoro, 9α-fluoro, 16-methyl, and 16-methylene substituents, are described. Key synthetic stages were the preparation of carbothioic acids and their reaction with dihalomethanes. The carbothioic acids were formed from 17β-carboxylic acids by initial reaction with dimethylthiocarbamoyl chloride followed by aminolysis of the resulting rearranged mixed anhydride with diethylamine, or by carboxyl activation with 1,1'-carbonyldiimidazole (CDI) or 2-fluoro-N-methylpyridinium tosylate (FMPT) and reaction with hydrogen sulfide, the choice of reagent being governed by the 17α-substituent. Carboxyl activation with FMPT and reaction with sodium hydrogen selenide led to the halomethyl 16-methyleneandrostane-17β- carboselenoate analogues. Anti-inflammatory potencies were measured in humans using the vasoconstriction assay and in rats and mice by a modification the Tonelli croton oil ear assay. Best activities were shown by fluoromethyl and chloromethyl carbothioates with a 17α-propionyloxy group. S-Fluoromethyl 6α,9α-difluoro-11β-hydroxy-16α-methyl-3-oxo-17α-(propionyloxy)androsta- 1,4-diene-17β-carbothioate (fluticasone propionate, FP) was selected for clinical study as it showed high topical antiinflammatory activity but caused little hypothalamic-pituitary-adrenal suppression after topical or oral administration to rodents.
- Phillipps,Bailey,Bain,Borella,Buckton,Clark,Doherty,English,Fazakerley,Laing,Lane-Allman,Robinson,Sandford,Sharratt,Steeples,Stonehouse,Williamson
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p. 3717 - 3729
(2007/10/02)
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