3-Fluoro-1- -2-propanol

This point is well illustrated with a spectrum of 3-fluoro propanol (Spectrum 6.10), which shows a fairly dramatic example of fluorine coupling. The F-CH2- coupling is about 47 Hz, and the F-CH2-CH2- coupling, is 27 Hz. The coupling to the third methylene group is non-existent in this example but can be seen sometimes (0-3 Hz). 

The following homologues were prepared from 3-fluoro-propanol by suitable modifications of technique 2-3 -fluoroprop-... 

This was verified by showing that ethyl 2-fluoroethyl carbonate was as toxic as 2-fluoroethyl alcohol. Furthermore, we found that /9-2-fluoroethoxypropionic acid was indeed toxic, whereas /9-3-fluoropropoxypropionic acid was non-toxic.1 (3-Fluoro-propanol is itself non-toxic.)... 

The stability under irradiation of the calix[4]arene-bis(tm-octylbenzo-crown-6) (BOBCalixC6)-based solvent system (mixture composed of calix[4]arene, an aromatic fluoro-propanol as modifier, and trioctylamine in aliphatic diluent) was tested under chemical and radiolytic conditions representative of the alkaline-side process (265). After y-irradiation doses as high as 0.16 MGy, no significant loss of BOBCalixC6 was measured (less than 10%). 

The effect of radiolysis on complexed solutions proposed for the FPEX process was investigated. The calixarene BOBCalixC6 was present with substi-tuted-18-crown-6, aromatic fluoro-propanol as modifier, and trioctylamine in aliphatic diluents (35). The effect of gamma irradiation was negligible up to 0.02 MGy. An important change of coloration and the appearance of a third phase was observed, but due to the nitration of the modifier. Instead of the BC-6 and oct-MC6 calixarenes, which presented a decrease of Cs extraction after radiolysis, the presence of alkylated phenyl moieties provided protection for the Cs site. 

As part of a study on cell-surface glycans, 2,3-bis(tetradecyloxy)propyl 2-deoxy-2-fluoro-a- and - -D-mannopyranosides were prepared by condensation of 3,4,6-tri-0-benzyl-2-deoxy-2-fluoro-a-D-mannopyranosyl chloride with 2,3-bis(tetradecyloxy)propanol. 

The resolution of the overall reaction into steps implied by the steric effect (above) has been achieved" for the oxidation of isopropanol. In 97% aqueous acetic acid a rapid reaction, ic2 x 1.25x10 l.mole . sec (15 °C, p = 0.183 Af NaC104), which is unaffected by deuteration, precedes the oxidation. Evidence for an intermediate has been reported for the oxidation of 1,1,1-tri-fluoro-2-propanol at very high acidities . 

The synthesis of halcinonide is summarized in Figure 1, starting with 16a-hydroxy-9a-fluorohydrocortisone (A1 -pregnene-9a-fluoro-llg,16a,17a,21-tetrol-3,20-dione dihydrotriamcinolone, I), which is available commercially.10-13 This tetrahydroxy steroid is slurried in acetone, and then 70% perchloric acid is added slowly. The acetonide, II (9a-fluoro-llg, 16a, 17, 21-tetrahydroxypregn-4-ene-3, 20-dione, cyclic 16,17-acetal with acetone dihydrotriamcinolone-acetonide) precipitates spontaneously from solution. Mesyl chloride is added to the acetonide in pyridine to give the 21-mesylate derivative (dihydrotriamcinolone acetonide-21-mesylate, III). Compound III is dissolved in dimethylformamide, lithium chloride is added and the mixture is refluxed to produce halcinonide (IV), which is recrystallized from a solution of ft-propanol in water. 

The radiosynthesis starts with the nucleophilic F-fluorination of 2-benzyloxy-4-formyl-A/,A/,A/-trimethylanilinium trifluoromethanesulfonate or 5-benzyloxy-2-nitrobenzaldehyde. Subsequent condensation with nitroethane yielded the corresponding 2-nitro-1-propanol derivatives. Reduction of the nitro moiety and deprotection provided the four stereoisomers of " F-labeled 2-amino-1-(4-fluoro-3-hydroxyphenyl)-1-propanol and 2-amino-1-(2-fluoro-5-hydroxyphe-nyl)-1-propanol, respectively. 4-p F]FMR was isolated from the 2-amino-1-(4-fluoro-3-hydroxyphenyl)-1-propanol stereoisomer mixture via semipreparative HPLC and additional chiral HPLC for enantiomeric resolution. In a similar manner enantiomeric pure 6-p F]FMR was obtained. From a synthetic point of view, 4-p F]FMR appeared to be the more promising candidate for PET investigations due to higher radiochemical yields. The main advantage of the nucleophilic approach over the electrophilic methods is the obtained high specific radioactivity (56-106 GBq/pmol) that is desired for safe use in humans with tracer doses far beyond the pharmacological level [173]. 

Treatment of the 9-fluoro-l,4-dien-3-ol (15) with 3.5 g-atoms of lithium and l-methoxy-2-propanol in ammonia reductively cleaves the allylic 3-hy-droxyl group to give tbf corresponding 3-desoxy compound, but the fluorine... 

Ethane 2-Fluoro-2-methoxy-l,l.1-trichloro- V/3. 201 (Cl > F) 2-Propanole 3-Fluoro-l,l.l-... 

Propanole 3-Fluoro-l-mcthoxy-E10b,. 152 (Oxirane + R4N H2Ff)... 

Eluoro- E10b2. 18 (En/EI20,) 1-Propanole 2-Fluoro-3-isopropyl-oxy- F.IOa. 635 (Oxirane + KHF2 AIF3)... 

Pentanoate Ethyl 2-Fluoro-3-hydroxy-3-methyl- ElOb, 454 (Ketone + F-CH2-COOR) Propanoatc tert.-Butyl 2-Fluoro-2-methoxy- ElOa, 495 (Na F) 2-Propanole 3-Fluoro-l-(2-tetra-hydropyranoyloxy)- ElOb, 152 (Oxirane + R3N H,F3)... 

Propanole 2-(4-Fluoro-phenyl)-hexafluoro- ElOa, 329 (Educt) ElOb,. 85 (Educt)... 

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