Formaldehyde oxime

Cyclization of 8-hydrazinO 3-phenyl-l-azaazulenes 69 with triethyl orthoformate gave 4,5-triazabenz[c(f]azulene derivative 70 which was easily hydrolyzed on silica gel and gave (2-chloro-8-imino-3-phenyl-l-aza-l,8-dihydoazulen-l-yl) formaldehyde oxime (87H767) (Scheme 17). 

Spectroscopic Data. Freshly prepd nitrosomethane has an IR absorption band at 6.3—6.4 p which slowly decays and is replaced by a band at 11 y characteristic of formaldehyde oxime (Ref 8). The visible absorption Amax is 287my in eth and at 266—7m p in w (Ref 4)... 

While highly reactive formaldonitrone (3) was detected only recently, both the nitrosomethane (1) and the formaldehyde oxime (2) are also reactive compounds in the condensed phase 2 undergoes facile oligomerization , whereas 1 forms a dimer and isomerizes to 2 . Deprotonation of any of these isomers (1, 2, 3) would result in the corresponding simplest nitrosomethanide anion [H2C=N—O]. ... 

Interestingly, the oldest experimentally known isomer is formoxime (2), nowadays better known as formaldoxime (the oxime of formaldehyde—formaldehyde oxime), which was first synthesized as early as 1891. Scholl already reported that 2 is unstable with respect to slow polymerization, while Dunstan and Bossi were able to stabilize 2 as its hydrochloride salt and described its properties in 1898 . Dunstan and Bossi also reported the reaction of 2 HC1 with alkali metals yielding the sodium salt of 2, Na+ [H2C=NO] , which explodes when heated . Probably, this explosive statement was one of the first descriptions of a nitrosomethanide. 

Diazomethane (called Diazomethan in Ger), C cNiN mw 42.04, N 66.64% poisonous yel gas condensing to a yel liq, bp -24 to -23° and solidifying in pale-yel crysts, fr p -145° explodes violently when heated to a higher temp sol in eth more important methods of prepn are from nitrosomethylurea, nitroso-methylurethane, a mixt of chloroform fit hydrazine hydrate, or l-methyl-l-nitroso-3-nitro-guanidine by reaction with KOH from nitrosyl chloride methylamine by treatment of the Na salt of formaldehyde oxime with chloramine and by other methods... 

For hydrogen bonds weaker than OH 0=C or NH 0=C, theory predicts smaller differences in the X-H bond lengths and negligible changes in the nonhydrogen bonds. TWo models have been studied theoretically with the ab-initio molecular orbital method at the HF/3-21G level of approximation. These are formaldehyde oxime cyclic dimer versus the monomer [378] and formaldehyde hydrazone cyclic dimer versus the monomer [379]. Except for the O-H and N-H bonds, these differences are too small to be detected by single crystal X-ray or neutron diffraction methods, as shown in Fig. 5.2. 

Minh Tho, N., Vanquickenborne, L. G. Mechanism of the Beckmann rearrangement of formaldehyde oxime and formaldehyde hydrazone in the gas phase. J. Chem. Soc., Perkin Trans. 21993,1969-1972. 

Figure 12.66 (a) terms (in Hz) for cis- and trans-t-butylcyclohexanol. Both experimental and calculated (in parentheses) are given, (b) Comparison of j y terms for the syn and anti hydrogens in formaldehyde oxime. 

According to Nef, metallic fulminates can also be synthesized by the reaction of derivates of formaldehyde oxime with the relevant nitrate [15]. 

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