Secondary amines, derivatives

Reductive cleavage of phenylhydrazones of carbonyl compounds provides a route to amines. The reduction is carried out conveniently in ethanol containing ammonia over palladium-on-carbon. Ammonia is used to minimize formation of secondary amines, derived by addition of the initially formed amine to the starting material (160). Alternatively, a two-phase system of benzene, cyclohexane, toluene, or dioxane and aqueous hydrochloric acid can be used. 

Figure 1.114 The reaction of a reducing sugar with an amine-containing compound in the presence of sodium cyanoborohydride results in ring opening with the formation of a secondary amine derivative.

Figure 1.116 Released glycans can be labeled with small fluorescent compounds containing amines for subsequent detection upon chromatographic separation. In the presence of sodium cyanoborohydride these compounds react at the reducing end of glycans to form secondary amine derivatives with characteristic spectral properties.

The anion B12H11NH22 can form Schiff bases with aldehydes, which in turn can be reduced to amines, opening the way to both secondary amine derivatives of the B12H122 cluster and tertiary amines and quaternary ammonium salts after further alkylation [61]. 

Acyloxy)methyl carbamates (and A-[l-(acyloxy)alkoxycarbonyl] compounds in general) have the formula RR,N-C0-0-CHR,/-0-C0-R,/, where R" = H or Me, and COR " = acyl. Acetoxymethyl carbamates of model amines have yielded important information on the possibilities and limitations of these potential prodrugs. For secondary amine derivatives, a clean mechanism of activation was characterized, shown in Fig. 8.19 for one of the model compounds investigated [209]. Hydrolysis of the terminal ester moiety (Fig. 8.19, Reaction a) triggers the two subsequent breakdown reactions (Fig. 8.19, Reactions b and c). For compound 8.162 (Fig. 8.19), the tu2 value in buffer at pH 7.4 and 37° was 98 h, while it was 6.2 h in human plasma [210]. The parent secondary amine was hydrolyzed quantitatively. 

The classical post-column derivatization, as developed by Moore and Stein, 3 uses ninhydrin and detection is achieved at 570 nm for primary amine derivatives and at 440 nm for secondary amine derivatives with detection limits that strongly depend upon the instrumentation used. 

The asymmetric methylation of N-benzylidene-(R,S)-phenylalanine methyl ester was carried out195) in the presence of lithium salts of secondary amines derived from... 

Typical primary amines which undergo such nitrosation are m-toluidine, p-xylidine, m-anisidine, 2-amino-4-methoxytoluene, 3-amino-4-methoxy-toluene, m-aminophenol, a-naphthylamine, l-naphthylamine-2-, -6-, -7-, and -8-monosulfonic acids, and l-naphthylamine-4-monosulfonic acid (which reacts with displacement of the sulfonic acid group). The secondary amines derived from these primary amines also can be nitrosated directly (i.e., without the intermediate formation of an JV-nitroso compound which needs to be subjected to the Fischer-Hepp rearrangement). The entering nitroso group appears to substitute exclusively in the para position. 

Many important neurotransmitters are primary or secondary amines, derived from amino acids in simple pathways. In addition, some polyamines that form complexes with DNA are derived from the amino acid ornithine, a component of the urea cycle. A common denominator of many of these pathways is amino acid decarboxylation, another PLP-requiring reaction (see Fig. 18-6). 

Cyclizations occur with secondary amine derivatives, also. N-Allyl-o-iodoaniline produces 3-methyl-indole, for example, in high yield at 25 C using sodium carbonate as the base with tetrabutylammonium chloride in DMF solution (equation 24).7S Similar procedures have been applied to the synthesis of in-... 

Aldehyde groups can be converted into terminal amines by a reductive amination process with ammonia or a diamine compound. The reaction proceeds by initial formation of a Schiff base interaction—a dehydration step yielding an imine derivative. Reduction of the Schiff base with sodium cyanoborohydride or sodium bor-ohydride produces the primary amine (in the case of ammonia) or a secondary amine derivative terminating in a primary amine (for a diamine compound) (Fig. 88). 

In addition to secondary amines, primary amines could be employed furnishing the corresponding secondary amine derivatives as the final products in equally high diastereoselectivity. 

C. Le Page, M. Schaefer, A. M. Batt, and G. Siest, Dev. Biochem., 13,363 (1980). QSAR in a Series of Secondary Amines Derived from Perhexilline Maleate with Purified Phenobarbital-Induced Pig Liver Microsomal Cytochrome P-450. 

Although in many cases products 256 can be directly prepared by Mannich synthesis, the replacement reaction is particularly convenient (l)in the case of primary amines, as it yields a secondary amine derivative hardly obtainable through other synthetic routes, and (2) in the case of arylamincs, as it makes it possible to avoid engaging an activated, reactive, aryl group in the direct Mannich reaction. Moreover, the method is frequently adopted in the synthesis of polymeric substances (Chap. III). 

The gallium ririy-dialkyldithiocarbamates are monomeric sohds that possess relatively low volatility. Improved volatihty is achieved with asymmetric secondary amines derivatives for example, the use of [Ga S2CN(Me)Hex 3] in a LP-MOCVD affords o -Ga2S3 thin films at 500 °C on GaAs(l 11). Whereas the monothiocarbamato coordination complex [Ga(SOCNEt2)3] affords thin films of GaS at 450 Again a more comprehensive array of the... 

Various new procedures have been reported for the reduction of pyridine iV-oxides, including the use of TiCU with NaBH4 of (MeO)3P with of SO, generated in situ and of M0CI5 with zinc dust. Irradiation of pyridine N-oxide in the presence of sodium hydroxide yields the anion of 5-hydroxypenta-2,4-dienenitrile if the irradiation is carried out in the presence of secondary amines, derivatives of 5-aminopenta-2,4-dienenitrile are obtained. ... 

Primary and secondary amine derivatives of /ra ts-l-chIoro-2,2,3,4,4-pentamethylphosphetan 1-oxide (44) can be obtained by heating the compound and the amine in toluene in a sealed tube to 215 Detailed n.m.r. and i.r. data for the products show evidence for hindered rotation around the P—N bond, and some degree ofp -dv bonding is considered to be a contributing factor. The diphosphonic anhydride (45) which results when (44) is... 

Synthesis of PYML-1 was based on the Schiff base approach originally developed by the total synthesis of BLM (Fig. 16) [53]. Thus, condensation of aldehyde (28) and amine (7) gave Schiff base (29) which was reduced by catalytic hydrogenation. The resulting secondary amine derivative (30) was hydrolyzed and coupled with the histidine component. PYML-1 was obtained by deprotection of dipeptide (31). 

The classic direct Mannich reaction discovered in 1912 [192a] is an aminoalkylation of carbonylic compounds involving ammonia (or a primary or secondary amine derivative), a non-enolizable aldehyde (usually formaldehyde) or a ketone, and an enolizable carbonyl compound, leading to P-aminocarbonyl derivatives [192b-e]. The indirect version of the Mannich reaction is the corresponding two-component reaction of a preformed iminium salt [193] and an enolizable carbonyl compound. 

Lactate dehydrogenase Lacto-N-difucohexaose I (secondary amine derivatives)... 

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