Amine , primary, reaction with

Reaction with primary amines (Section 17 10) Isolated product is an imine (Schiff s base) A carbinolamine inter mediate is formed which undergoes de hydration to an imine... 

Fluorescamine reacts directly with primary amines to form fluorescent products. Secondary amines yield nonfluorescent derivatives which can be transformed into fluorescent products by a further reaction with primary amines. 

An interesting extrapolation of this synthesis deals with the preparation of the bispyridinium salt 62 from 1,2-phthalic dicarboxaldehyde and its subsequent reaction with primary amines (92BSB509).Tlie expected diimines 63 readily cyclize so that 2-aryl-l-arylimino-2,3-dihydro-l//-isoindoles 64 can be isolated in excellent yields (90-95%). Contrary to the reactions performed by employing the dialdehyde and amines directly, the syntheses involving the azinium salts do not produce those typical dark-colored complex mixtures of products (77JOC4217 85JHC449) (Scheme 20). 

Therefore in this section we will focus first on the reactions of arenediazonium ions with secondary amines such as A-alkylanilines and dialkylamines. Reactions with primary amines will be discussed later in this section. Most diarylamines do not undergo Af-azo coupling to a significant extent, as they are weaker nucleophiles. 

OH with acid chlorides and in turn may be converted to amides via reaction with primary amines. The conversion of N3P3C1 (NH2)2... 

The 9-fluoro group of the pyrimido[l,6,5-, tf][l,4]benzoxazine 312 has been exchanged for an amino group upon reaction with primary amines <2001W02001/053273>. 

Treatment of Baylis-Hillman (BH) derivatives 10, obtained from 3-(2-bromophenyl)-5-methyl-4-isoxazolecarbaldehyde, with tributyltin hydride allowed a straightforward synthesis of isoxazolo-benzazulene systems 11 along with minor amounts of the debrominated products 12 <06TL7043>. BH adducts made from 5-isoxazolecarbaldehydes were converted in moderate yields into pyrrole derivatives by reaction with primary amines and then DBU <06S1021>. 

The polymer-supported 5-chloromethyl-l,2,4-oxadiazole 162 undergoes easy reaction with primary amines to give the 5-aminomethyl oxadiazoles 163, which serve as excellent substrates for the synthesis of amides or sulfonamides 164 (Scheme 21 - yields not reported) <1999TL8547>. 

Figure 2 Structure of fluorescamine (FR) and its fluorogenic reaction with primary amines.

Related to the above are the reactions of pyridinium ions with nucleophiles. It has been known for many years that pyridinium ions can undergo ring-opening reactions with primary amines (70JA5641). Studies on the mechanisms of these reactions indicate that the interconversion of the dihydropyridine (48) with the acyclic dianils (49) of glutacondialdehyde is a key step in these reactions. 

The reaction of pyrazino[2,3-r-][l,2,6]thiadiazine-2,2-dioxides 61 with secondary amines proceeds very readily and allows access to, for example, the 4-pyrrolidinyl derivative 62 as shown in Equation (10). A similar reaction with primary amines allowed access to a range of 4-amino-pyrazino[2,3-r-][l,2,6]thiadiazine-2,2-dioxides 63, as shown in Equation (11) <2000JME4219>. 

Chloromethylation occurred in high yield at C-3 and C-4 when thienothiophene (73) was treated with paraformaldehyde and HC1 at 50 °C, to give chloromethyl derivative (96 Scheme 28). Treatment of the chloromethyl compound (96) with sodium acetate or sodium ethoxide gave the corresponding acetoxymethyl or ethoxymethyl derivatives (97). Analogous reaction with primary amines led only to the formation of bis-aminoalkyl compounds (98) and no peri-annelated products (99) could be detected (Scheme 29) <76AHC(19)123>. 

A specific behavior in reactions with primary amines was described for l-aryl-3-carboxy-benzo[c]pyrylium salts 62 (89KGS454). While their monocyclic analogs undergo decarboxylation with heteroatom exchange,... 

The use of solvents more polar and nucleophilic than benzene, e.g. ethanol, increases the electrophilicity of the sterically more-accessible position 3 because of the interaction of the cation with the solvent, and the addition of primary amines occurs in position 1. Thus, one may conclude that decarboxylation of salts 62 in the reaction with primary amines occurs by a preliminary addition of nucleophile, whereas the decarboxylation of isoquinolinium salts 161 to 162 proceeds by a ylide mechanism as is shown here. As known, the latter pathway requires the use of stronger bases and more elevated temperatures (79MI3). 

It was shown by Katritzky (80T679) that acetic acid promotes recyclization of triaryl-pyrylium salts in reactions with primary amines. 

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