Angelo G. Giumanini

The 1:1 phenylhydrazine–borane adduct, obtained from phenylhydrazine and sodium borohydride in acidic solution, was investigated by IR, NMR spectroscopy, and MS spectrometry. Ab initio MO calculations indicated the isomer in which the boron center is attached to the primary amino group as the more stable. This forecast was confirmed by solution‐state ¹H, ¹¹B, ¹³C, and ¹⁵N NMR spectroscopy, in agreement with the molecular structure in the solid state determined by X‐ray analysis. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:366–372, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10049

A multiple D2O-CH2N2 exchange followed by a final anhydrification with K2CO3 gave an alcohol-free low-water-content ether solution of CD2N2. Procedural improvements for the exchange are reported. The extent of deuteration with a quantitative evaluation of the actual species present in any solution of diazomethane could be determined by a GC-MS analysis and H-1 NMR spectrometry on a suitable derivative. In addition, a procedure for the quantitative determination of water in diazomethane solutions has been developed

The title compounds were promptly obtained in fair to good yields as distillable liquids by admiring 1,3,5-triarylhexahydro-1,3,5-triazines (1) with n-butyl nitrite (2) in anhydrous CH2Cl2 and were fully characterized by H-1 and (13)CNMR, IR, and MS. The pure products were invariably made up of geometric isomers which did not interconvert rapidly at room temperature. o-Substituents could cause difficulties in the free rotations of the aryl substituent about the C-N bond as well of the alpha-butoxymethyl group. The reaction is believed to occur on the monomeric imines derived from the thermal equilibration of their trimeric and dimeric precursors. Aliphatic hexahydrotriazines were found to be unreactive under the present conditions

The presence of a free carboxyl or ester function on the alpha-carbon of toluene induces the nitration of the phenyl ring in the ortho position at or above the statistical value (chaperon effect), when pure HNO3 is used in CH2Cl2 solution. This is at variance with the results of classical nitration in H2SO4, where p-nitration predominates by far and m-nitration occurs at a remarkable extent. The new finding is explained in terms of precomplex formation

The first trimeric N-methylideneamine from a heterocyclic amine (4-aminoantipyrine, 1) has been fully characterized and its X-ray diffraction structural determination carried out; also the equilibrium between the trimer 2 and the monomer 3 has been studied by ¹H and ¹³C NMR spectroscopy.

Primary aromatic amines 1 with a variety of ring substituents are easily converted to their N-monoalkyl derivatives 3 by a simple variation of the sodium borohydride/sulfuric acid/carbonyl compound procedure previously described for their N-permethylations. The procedure is suitable for the α-monodeuterium labelling of the new N-substituent.