Nitrosyl fluoride

I Baker and Adamson, Morristown, N.J. The commercial material should be dried for 6-15 hrs. at 240°, powdered with a warm mortar and pestle, and reheated to 240° for several hours. 

Most of the solvent is removed by pumping at ambient temperature. Then cleavage of the salt-acetone adduct and removal of the remaining solvent are carried out at 100° while pumping for 2 hours. A —195° cold trap is placed on the vacuum line to allow collection of the volatile materials for reuse in preparing more salt. This procedure allows the salt to be coated on the walls of the vessel in a finely divided state as the volatile acetonitrile and hexafluoroacetone are removed. 

When an incomplete reaction occurs, it is preferable to remove the volatile FNO while the vessel is held at —78 , leaving the unreacted N2O4 condensed in the vessel. Nitric oxide may be found in the FNO stored in glass over KF at room temperature if traces of water are present. Nitric oxide may be removed from the FNO by pumping on the vessel cooled to —140 to — 196 . Any silicon tetrafluoride which may be formed is absorbed by the potassium fluoride. 

The metal reaction vessel containing the powdered salt is cooled to —78 , and 0.004 mole of NO2 is added under vacuum conditions. The metal vessel is then allowed to stand at room temperature for 12 hours. A sample of the gas can then be checked for completeness of reaction by infrared analysis or by observing the color of the product gas. If the reaction is not complete, the prepared FNO can be removed at —78 from the NO2 condensed in the vessel however, total reaction is necessary 

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Arsenic trifluoride (arsenic(III) fluoride), AsF, can be prepared by reaction of arsenic trioxide with a mixture of sulfuric acid and calcium fluoride or even better with fluorosulfonic acid. Chlorine reacts with ice-cold arsenic trifluoride to produce a hygroscopic soHd compound, arsenic dichloride trifluoride [14933-43-8] ASCI2F35 consisting of AsQ. and AsF ions (21). Arsenic trifluoride forms a stable adduct, 2AsF2 SSO, with sulfur trioxide and reacts with nitrosyl fluoride to give nitrosonium hexafluoroarsenate(V) [18535-07-4] [NO][AsFg]. 

Boswell,making use of the methodology elaborated by Martin and Kagan, prepared a series of 6,6-difluoro-A -3-ketones closely related to the steroid hormones, exemplified by the conversion of 3)5,17a-dihydroxypregn-5-en-20-one diacetate (7) to 6,6-difluoro-17a-acetoxyprogesterone (12). Reaction of (7) with nitrosyl fluoride at 0° affords the nitrimine (8), which is... 

The reactions of A -steroids with nitrosyl fluoride parallel those of their A -isomers. Thus, 17 -acetoxyandrost-4-ene (37) is converted to the nitrimine (38), in 67 % yield and thence to the 4-ketone (39), which can be dehydrofluorinated to the A -4-ketone (40) with lithium bromide in di-methylformamide. In the corresponding 19-nor series the nitroso dimer is also formed. 

A -Steroids react sluggishly with nitrosyl fluoride to yield after alumina chromatography the nitro-olefin (44) (14 %), and 0.7 % of the 2a-fluoro ketone (45), the former probably arising by alumina-catalyzed dehydrofiuorination of an intermediate 2-fluoro-3-nitro adduct. 

The double bond of a, -unsaturated ketones reacts with nitrosyl fluoride but only at room temperature and in small yield. Cholestenone produces a 4.2% yield of a 4< -fluoro-5( -nitro-3-ketone (46) after alumina chromatography. Similarly, the A -20-ketone grouping in 3j5-acetoxypregna-5,16-dien-20-one (47) reacts to form after chromatography a 14% yield of the... 

The reaction of 9(1 l)-dehydro steroids with nitrosyl fluoride was studied by Grantz and Rosenthal in pursuit of an alternate source for the important 9a-fluoro-11-oxygenated steroids. As expected, reaction at the more hindered 9(1 l)-double bond proceeds more slowly than at either the 4- or 5-double bonds. After 10 days at 3°, 3 -acetoxy-5a-pregn-9(l l)-en-20-one (50) affords a 45% yield of the 9a-fluoro-ll-nitrimine (51). Other 9a-fluoro-ll-nitrimines were prepared and it was found that the presence of additional keto groups, particularly the 3-keto group gives rise to side products with a concomitant reduction in yield of the desired 9a-fluoro-ll-nitrimines. In the case of the A" -3-ketones the yield is reduced to 10 %. The steric hindrance... 

It is noteworthy that treatment of the 9(ll)-dehydro steroid (50) with nitrosyl fluoride in ethyl acetate at 50° affords after chromatography a 20% yield of the A hi2-ketone. ... 

Mechanism The reaction of and A -steroids with nitrosyl fluoride to form ni trimines is best discussed in conjunction with the nitrosyl chloride reaction leading tothe5a-chloro-6 -nitro steroids (33). Since nitroso alkanes are oxidized with nitrosyl chloride to nitro alkanes it is believed that 5a-chloro-6j5-nitro steroids are formed in this way from an initially formed 5a-chloro-6 -nitroso adduct. The same is true for nitrosyl fluoride up to the stage of the nitroso fluoride (56). Since NOF is a weaker oxidizing agent than NOCl the nitroso fluoride tautomerizes to the fluoro oxime (57) at a rate... 

Nitrosyl fluoride reacts with steroidal olefins to give, ultimately, a-fluo-roketones [131], with steroidal vinyl lluorides, the reaction provides a,a di fluoroketones from intermediate nitroimines [197] (equation 34)... 

Fluorinated olefins react with nitrosyl fluoride [131], dinitrogen tetroxide and fluoride ion [131], or nitrosyl chloride and fluoride ion [19S, 199] (equations 35 and 36) to afford fluoronitioso compounds Tertiary fluoroniUoso compounds are a convenient source of tertiary perfluoroalcohols... 

Nitrosyl chloride [55], nitrosyl fluoride-hydrogen fluoride liquid complexes (NOF3HF, NOF 6HF) [56], nitrous acid-hydrogen fluoride solutions [57, 5 ] nitrogen trioxide (prepared in situ from nitric oxide and oxygen) [59] and rert-butyl nitrite-hydrogen fluoride-pyndine [60] have been substituted for sodium nitrite in the diazotization step... 

Doyle and Bryker (1979) reported high yields of arenediazonium tetrafluoroborates when aromatic amines were reacted with tert-butyl nitrite and trifluoroboro etherate in CH2C12. It is likely that nitrosyl fluoride is formed as nitrosating reagent by fluoride-alkoxy exchange. 

Nucleophilic catalysis is also observed with iodide ions. Fluoride ion does not form nitrosyl fluoride under diazotization conditions, as is to be expected from Pearson s hard and soft acids and bases principle which was discussed briefly in Section 3.2. More recently, nucleophilic catalysis has also been shown to occur with thiocyanate ion (SCN ), thiosulfate ion (HS2Of), dimethyl sulfide, and thiourea (H2NCSNH2) or its alkyl derivatives (see below). 

The scheme required to prepare the potent tri-fluoro corticoid cormethasone acetate (292) illustrates the synthetic complexities involved in some of this work. Sequential acetylation of the pregnenolone derivative 278 with first acetic anhydride in pyridine and then acetic anhydride in the presence of tosic acid affords diacetate 279. Reaction of that intermediate with nitrosyl fluoride results initially in addition of the reagent to the 5,6-olefin moiety to afford the fluoro oxime reaction with a second mole of reagent at nitrogen gives the nitroimine derivative 280 passage over alumina serves to hydrolyze the imine function to the corresponding 6-ketone (281). 

Dichlorine oxide Oxidisable materials Nitrosyl fluoride Metals, etc. 

Lead(II) oxide Non-metals Lead(IV) oxide Non-metals Nitric acid Non-metals Nitrogen oxide Non-metals Nitrosyl fluoride Metals, etc. Nitryl fluoride Non-metals Oxygen difluoride Non-metals Potassium nitrite Boron Potassium nitrate Non-metals Silver difluoride Boron, etc. Sodium peroxide Non-metals... 

Iodine pentafluoride Metals Nitric acid Metals Nitrosyl fluoride Metals Perchloric acid Bismuth See other METALS... 

Adducts of the hexafluoride with sodium fluoride, potassium fluoride, rubidium fluoride, caesium fluoride or nitrosyl fluoride react violently with water. 

Nitrosyl fluoride Sodium Nitiyl fluoride Metals Sodium nitrate Sodium MRH 3.85/43... 

Dichlorine oxide Oxidisable materials Iodine pentafluoride Metals Iodine Metals Nitrosyl fluoride Metals Perchloric acid Antimony(III) compounds Potassium dioxide Metals Potassium permanganate Antimony, etc. 

Lead(II) oxide Non-metals Nitrosyl fluoride Metals, etc. Oxygen difluoride Non-metals Peroxyformic acid Non-metals Silver fluoride Non-metals... 

Nitropropane Nitrosyl fluoride Nitrosyl perchlorate Nitrourea Nitrous acid Nitryl chloride Oxalic acid See under Nitromethane chlorosulfonic acid, oleum Haloalkenes, metals, nonmetals Acetones, amines, diethyl ether, metal salts, organic materials Mercury(II) and silver salts Phosphine, phosphorus trichloride, silver nitrate, semicarbazone Ammonia, sulfur trioxide, tin(IV) bromide and iodide Furfuryl alcohol, silver, mercury, sodium chlorate, sodium chlorite, sodium hypochlorite... 

Nitryl Fluoride Nitrosyl Fluoride Thionyl Fluoride Sulfuryl Fluoride... 

Nitrogen trilluoride, 4336 Nitrogen triodide, 4633 Nitrogen triiodide-silver amide, 4634 Nitrogen triiodide-ammonia, 4635 Nitrosyl chloride, 4023 Nitrosyl fluoride, 4302 Nitryl chloride, 4025 Nitryl fluoride, 4303... 

Nitration of the amine (139) with mixed acid yields the energetic nitramine (140). The same reaction with sodium nitrite in sulfuric acid, or with nitrosyl fluoride in methylene chloride, yields the nitrosamine (141), which is also an energetic high explosive. ... 

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