Nitrimines

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... 

In contrast to the wide application that nitrosyi chloride has found in terpene chemistry, nitrosyi fluoride has only recently been discovered. Its first use in steroid chemistry was reported by Boswell who treated cholesterol acetate with nitrosyi fluoride at 0° in methylene dichloride and obtained the 5a-fluoro-6-nitrimine (31) already mentioned in section VI (page 461) in connection with the synthesis of 6,6-difluoro steroids. This... 

In the 19-nor series, the reaction with NOF is more complex and there is isolated in addition to the fluoro nitrimine corresponding to (31) a 20% yield of the nitroso dimer (34), which dissolves in methanol-methylene dichloride solution to give the pure blue color characteristic of the monomer (35). The latter then isomerizes to the oxime (36). 

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. 

Both the 4- (38) and 6-(31) nitrimines are reduced with sodium boro-hydride to the corresponding y5-nitramine derivatives, e.g., (41)], which are methylated with methyl iodide and potassium carbonate. The A -methyl derivative is reduced in modest yield to the 5a-fluoride (43) with lithium aluminum hydride. 

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... 

Imines with an electron-withdrawing group at the nitrogen atom are excellent acceptors for the acetate (1) or the carbonate (13) [36]. Thus, N-tosylimines (84) gave very good yields of pyrrolidines (85) under typical conditions. The strained cyclic imine (86) and a,/ -unsaturated imine (87) both participated smoothly in the cydoadditions. The hindered nitrimine (88) also reacts well with (1) (but not with 13) to produce the pyrrolidine (89) with a 17 1 diastereoselectivity. However, the unhindered nitrimines from cyclohexanone and 2-nonanone failed to react presumably due to enolization (Scheme 2.24). 

Scholl et al (Refs 3 4) prepared the same compds by treating ketoximes (such as pina-colone) with nitrogen tetroxide, but he assigned them the structure R2C=N-N02 and called them nitrimines. One of the compds described by him in Ref 4, p 27 is a weak expl. It is the Ag salt of pinacolone-nitraminic acid which puffs off on rapid heating (this compd described below under List of Nitrimines ). Further work on... 

Fusco et al (Ref 10), Hantzch (Ref 7), Ponzio (Ref 8), and Saccardi and Latini (Ref 9). Suggitt et al gave a brief general review on nitrimines and described the prepn and properties of many of these compds (Ref 11)... 

Nitrimines seem to exist in several isomeric forms and their structures have not been definitely established. For instance, four different structures for mesityl nitrimine are given by Suggitt et al in Ref 11... 

A discussion of nitrimines usage as energetic materials is part of the article entitled Amines Nitrated and Nitrited in Vol 1, A174-R to A178-R... 

Hexanitrodiphenylguanidine. Note guanidines are included here, although A.F. McKay et al (Ref 4) states .. . these compds should not be classed as nitrimines ... 

Ref 1) Beil 7, (3S6)-,Note Beil does not differentiate between a nitrimine and a nitroimine. 

Both compd types are listed under Nitroimines by Beil and are so presented here. Perhaps this method of presentation is because of the lack of a nitrimine structural definition... 

Nitrimine werden durch Kaliumboranat in waBrigem Athanol zu Nitraminen reduziert17 z. B. ... 

This nitrimine, the nominal monomer of the cyclic nitramine high explosives RDX and HMX, may be involved in their detonation and can be formed from them by pyrolysis. 

There are four important groups of A-nitro compounds which are relevant to energetic materials synthesis. These are primary nitramines, secondary nitramines, secondary nitramides (including A-nitroureas and A, A -dinitroureas) and nitrimines. The synthesis and incorporation of these A-nitro functionalities into organic compounds is the focus of this chapter. 

Nitrimines are a relatively minor group of At-nitro compound. The nitro derivatives of guanidine and related compounds are the most important examples of the nitrimine group. 

Boyer and co-workers" also reported the synthesis of the guanidine tricycle (122), prepared as the tetrahydrochloride salt from the condensation of two equivalents of guanidine with 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine in concentrated hydrochloric acid. Treatment of the tricycle (122) with absolute nitric acid yields thebis-nitrimine (123), whereas the same reaction with nitric acid-acetic anhydride yields HHTDD (117). 

Di methyl-3,3-d in itrohutane, (H3C)3C.C(N02)2 CH3, crysts, having a strong camphor odor, very volatile, mp 173—74° easily sol in ether obtd in a small quantity from pinacoline oxime N2O4, in addn to pinacoline nitrimine (Ref 5)... 

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