Formaldehyde dimethylhydrazone

Nitrile oxides react in situ with formaldehyde dimethylhydrazone (129) to give oxime-hydrazones RC( NOH)CH NNMe2 (R = 4-O2NC6H4, MeCO, MeC ( NOH)). The reaction is performed on treatment of oximes with CH2 NNMe2 in the presence of Et3N without isolation of the intermediate nitrile oxides. 

Dimethyl 3-cyano-l,2,4-triazine-5,6-dicarboxylate (445) reacts with formaldehyde dimethylhydrazone (446) via a [4 + 2] cycloaddition to give the dihydropyrimidine (447) in very low yield (82CZ100). 

The 1,5-dialdose derivative 201 has been chain-extended to the 1,6-dialdose derivative 202, by stereospecific addition of formaldehyde dimethylhydrazone, according to Scheme 21.403... 

Formaldehyde dimethylhydrazone and phosphorus tribromide gave the unstable phosphonous dibromide (18) which could be converted to a distillable phosphonous diamide (19). Phosphorus tribromide reacts with 2-methylfuran in a 1 1 molar ratio to give 5-methyl-2-furanylphosphonous dibromide (20) a 1 2 molar ratio gave the pure bis(furanyl)phosphinous bromide. Unsubstituted... 

Formaldehyde dimethylhydrazone readily added to nitro-alkene 21 under neutral conditions and gave branched-derivative 22 as the major diastereomer. The hydrazone group in 22 was further transformed to an aldehyde or nitrile functional group by treatment with ozone or magnesium monoperoxyphthalate, respectively. The same reaction with other sugar nitro-alkenes has been previously described in preliminary form. (See J.-M. Lassaletta and R. Fernandez, Tetrahedron Lett., 1992,32, 3691). ... 

Figure 11.15 (a) First mechanism proposed for formation of NDMA by chlorination of water via reaction of chloramines with a dimethylamine to form chlorodimethylamine (CDMA) and thence unsynunetrical dimethylhydrazine (UDMH). (b) Further reactions of UDMH with chloramines to form NDMA plus other identifiable reaction products dimethyldiazene (DMD), tetram-ethyltetrazene (TMT), dimethylcyanamide (DMC), dimethyl-formamide (DMF), formaldehyde dimethylhydrazone (FDMH), formaldehyde monomethylhydrazone (FMMH). Reproduced from Mitch, Env. Sci. TechnoL 36, 588 (2002), copyright (2002) with permission of the American Chemical Society. 

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