Dibenzylamine compound 4, hydrogenation

Schiff bases, also known as imines, ate formed by the condensation of carbonyl compounds with ammonia or primary amines. Hydrogenation of the resulting Schiff bases forms amines, such as benzylamine and dibenzylamine. 

Dibenzylamine, [103-49-1], C6H5CH2NHCH2C6H5 (bp, 300°C at 101.3 kPa) is produced by reaction of benzyl amine with benzaldehyde and hydrogenation of the Schiffs base. It is used in mbber and tire compounding, as a corrosion inhibitor, and as an intermediate in the production of rubber compounds and pharmaceutical products. 

Reductive alkylation of ammonia may proceed under mild conditions over nickel catalysts. In examples using Raney Ni, temperatures ranging from 40 to 150°C and hydrogen pressures of 2-15 MPa have been used to obtain satisfactory results.3,4 In general, the reductive alkylation of ammonia with carbonyl compounds may produce primary, secondary, and tertiary amines, as well as an alcohol, a simple hydrogenation product of the carbonyl compound (Scheme 6.1). The selectivity to respective amine depends primarily on the molar ratio of the carbonyl compound to ammonia, although the nature of catalyst and structure of the carbonyl compound are also important factors for the selectivity. As an example, the reaction of benzaldehyde in the presence of 1 equiv of ammonia in ethanol over Raney Ni gave benzylamine in an 89.4% yield while with 0.5 molar equivalent of ammonia dibenzylamine was obtained in an 80.8% yield (eq. 6.1).4... 

Irradiation (X > 300 nm) of solutions of the Schiff bases N-benzylidenebenzyl-amine and N-benzylideneaniline in propan-2-ol in the presence of either platinised titanium(IV) oxide or platinised CdS induces transfer hydrogenation to give the corresponding secondary amines, dibenzylamine and N-benzylaniline respectively. Donor-acceptor compounds of the type N,N -dicyanobenzo[b]-naphtho[2,3-e][l, 4]dithiin-6,11 -quinonediimine, N,N -dicyanobenzo[b]naphtho... 

For benzylamine (entry 8) the arylation reaction with m-trifluoromethylbenzene remains the main process (yield 46 %). The only other fluorinated product observed, but the starting compound, is the trifluoromethylbenzene (29 %). In a parallel way, the arylation reaction is apparently accompanied by a partial amine dehydrogenation into the corresponding imine 1, whose formation could explain the presence of N-benzylidene benzylamine 2, and dibenzylamine 2, this last one being detected in small amount. These results are described in the Scheme 1 in which the nickel complex could act as a catalyst for the (de)-hydrogenation processes (refs. 10, 11). 

Many communications have concentrated on specific amino phosphonic acids or derivative types. Thus, esters of phosphonoaminoacetic add were obtained by the reactions between trialkyl (ethyl) phosphite and (218) and which are thought to proceed via the phosphorane (219). A sequence has been presented for the preparation of the mono- and di-benzyl esters of N-chz protected (a-aminoben-zyl)phosphonic acid. A synthesis of (aminomethylene)bisphosphonic acid from dibenzylamine, dibenzyl hydrogenphosphonate and triethyl orthoformate has been noted and the asymmetric hydrogenation of (220) in the presence of chiral phosphine catalysts yields samples of (221) with e.e.s of 63-96%. The pyrrolidine-based compound (222) has been prepared from methyl S)-N-methoxycarbonyl-4-oxo-2-pyrrolidinecarboxylate and iV-coupled 4-amino-butanal diethyl acetals were the starting materials in syntheses of the pyrrolidine-2-phosphonic add derivatives (223) in which Z represents the iV-protected amino add or peptide moiety. ... 

The commercial ACECs investigated can be considered as individual chemical compounds. The epoxy groups (in the ACEC), carboxyl group (in the acid) or active hydrogen atoms (in aniline) ratios were stoichiometric The reaction with the acid and with aniline was carried out at 80 and 100 °C, respectively. The addition of the acid was accelerated with N,N-dibenzylamine (1% of the epoxy component). 

The Amadori rearrangement also occurs for the glycosylamine derivatives of some secondary alkylamines and of primary and secondary aralkyl-amines it occurs in alcoholic solution in the presence of compounds such as ethyl malonate and acetylacetone which contain active hydrogen atoms 66), The direct reaction product from D-glucose and dibenzylamine was actually 1-dibenzylamino-l-deoxy-D-fructose (XI) 66) and not VjV-di-benzyl-D-glucosylamine (XII) as indicated earlier by Kuhn and Birkofer 76), This rearrangement was effected without benefit of acid catalysis 70) or by the use of ethyl malonate 66), The true V,i T-dibenzylglu-cosylamine (XII) could not be isolated. 

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