Primary amine reaction

Recently, FTIR spectroscopy studies have been reported which support the above observations. Moacanin et al 3) concluded that two reactions dominate the TC3fDA/DDS cure epoxy-primary amine addition is the principal reaction occurring during the early stage of cure followed by the epoxy-hydroxyl addition reaction. Indeed they find that the rate of epoxy-hydroxyl addition is at least an order of magnitude slower than for the epoxy-primary amine reaction at 177 C. Furthermore, Morgan et al (4) report that the epoxysecondary amine addition and epoxy-epoxy homopolymerization reactions also occur at 177°C but at rates that are approximately 10 and 200 times slower, respectively, than the epoxy-primary amine react ion. 

Figure 3.16—Flow cell of a fiuorimetric detector (reproduced by permission of Hewlett-Packard Inc.). One example of a reagent that is used to form fluorescent derivatives with compounds containing primary amines. Reaction of OPA in the presence of monothioglycol.

Pyrrolinones are best obtained by cyclizative condensation of y-keto esters with ammonia or a primary amine (reaction 195). Alternatively, the 2-pyrrolinones may be obtained by cyclization of preformed a-keto amides as shown in reaction (196) (71CC346). Preexisting lactones (2H- or 5H-furanones) also react with amines to give pyrrolinones (reaction 197). Jones and Bean give references to specific examples of these methods as well as to more specialized examples (B-77MI30610). 

The interpretation of the kinetics is based on the mechanisms proposed by Schechter et al.55) and Smith 57), for the reaction of secondary amines with epoxides, extended to include the primary amine reaction. The rate-determining step is assumed to be the reaction of amine, epoxide and hydroxyl or other proton-donor species, HX, to form a termolecular complex, Eq. (3-13). The proposed reaction scheme is ... 

The Gabriel synthesis is a classical but useful preparative method for primary amines. Reaction of an alkyl bromide (24) with potassium phthalimide (25) gives the corresponding A -alkylphthalinude (26), which upon treatment with hydrazine followed by KOH affords the primary amine (27). When a chiral alkyl halide is used in the Gabriel synthesis, a chiral primary amine is obtained. However, preparation of optically active alkyl halides is not easy. If optical resolution of 26 which has a chiral alkyl group can be done, a new preparative method for optically active amines can be established by a combination of the resolution with the Gabriel synthetic method. Some examples of the combination method are described. 

The reductive cleavage of the N—O bond of oximes is a reaction which has been widely used by synthetic chemists. When accompanied by reduction of the C=N bond the reaction leads to the formation of primary amines. Reactions of this type are described in Chapters 1.2-1.8, this volume. The reductive cleavage of cyclic oximes, particularly isoxazoles and 4,5-dihydroisoxazoles, has been used as a key step in several target syntheses of natural products. These cleavage reactions are covered in Chapter 3.8, this volume however, some of the methods which clearly bring about cleavage of the N—O bond before reduction of the C=N bond are also described in this section. The products of these reactions are A-unsub-stituted imines. Unless the imines are sterically protected or unless special precautions are employed in the work-up, the isolated products are usually carbonyl compounds formed by hydrolysis (Scheme 19). Reductive hydrolysis reactions of this type are also included here. 

Figure 3. Plot of Ca/(5a l) versus cure time to calculate rate constant (k ) for epoxy-primary amine reaction. (Reproduced from Ref. 4. Copyright 1986 American Chemical Society.)...

The rate coefficients for the secondary-amine reactions were found to be only 17% of those for the primary-amine reaction, thus explaining the residual secondary amine found at the end of cure. This equation was found to explain the development of the main crosslinking site, namely the tertiary-amine site formed on the DDS, corresponding to network interconnection. However, overlaid with the rate equation for chemical conversion that implies that all reagents are accessible to one another is the effect of the development of the network so that the reactions become diffusion-controlled. This is of interest since this means that the rate coefficients now reflect the chemorheology of the system, not just the chemistry. Thus, if and represent the rate coefficients for diffusion and chemical control, the measured rate coefficient, k, will be given by (Cole et ai, 1991)... 

Dinitrogen moieties are also targets of oxi-doreductases. Depending on their substituents, hydrazines are oxidized to azo compounds (reaction 7-A), some of which can be oxygenated to azoxy compounds (reaction 1-D). Another important pathway of hydrazines is their reductive cleavage to primary amines (reaction 7-C). Reactions 7-A and 7-D are reversible and the corresponding reduc-... 

Halides derived from hydrogen cyanide also react smoothly with primary amines. Reaction with cyanogen bromide is to be recommended as a method of preparing cyanamides, but it is advisable to arrange for good cooling so as to avoid formation of guanidines. 

An extensive series of amino-, N3P3F5 NR R (R = H, R = Et Ri = R2 = Et, Pr , or Bu ), andhydrazino-derivatives, N3P3Fb NH NR R (R = R = H or Me R = H, R = Me) has been obtained by direct reactions of amines and hydrazines with N3P3F6. With derivatives of primary amines, reactions with silylamines occur at the amino-group rather than at the phosphorus atoms ... 

Figure 4.19 Carboxylic acid reactive probes. Stabilization of an unstable 0-acylisourea intermediate by use of A/-hydroxysulphosuccinimide during the carbodiimide-activated combination of a carboxylic acid with a primary amine. Reaction normally occurs by steps A and B. With N-hydroxysulphosuccinimide the reaction now takes place by steps A, C and D.

A microwave-assisted Willgerodt-Kindler reaction was developed to synthesize a-aryl thioacetamides 16 from aromatic ketones, morpholine, and elemental sulfur (Eq. 3) [13]. The reaction is carried out without solvents and completes within 4 min. The reaction can also be used for aldehydes. The reaction temperature and times are dependent on the substituents in the aldehydes and amines [13,14]. The use of secondary cyclic amines gives the corresponding thioamides in good to high yields. In the primary amine reaction, higher reaction temperatures are necessary. Primary thioamides are formed by... 

PCI5. The former gives in addition the isomeric linear compound R C(N== PCl3)==C(CN)R, which is converted into the diazaphosphorine in the presence of HCl. Primary amine reactions with (101 R = Ph, R = CN) take place rapidly, substituting one chlorine at the phosphorus atom first, then replacing that at carbon before substituting the second chlorine at phosphorus. ... 

The Schiff base or enamine reaction has been employed to modify aldehydes and ketones by condensation with a primary amine (reaction 1) and to condense primary amines with a carbonyl compound (reaction 2). A similar reaction between primary amines and carbon disulfide yields isothiocyanates or mustard oils (reaction 3). These three possibilities for derivative formation will be discussed in this chapter. 

Pg. 4 - Para. 2. Is it true that the aromatic primary amines reaction with epoxy (the selective reaction in this instance) is catalyzed by acid Salicylic acid in conjunction with an alcoholic hydroxyl carrier (benzyl elcoholi nonyl phenol, furfuryl alcohol, etc.) may do it. But I doubt it if CTBN will. Perhaps I m wrong. But this needs explaining. 

A number of amine syntheses take advantage of the nucleophilic character of the alkyl (or aryl) group in a Grignard reagent. Thus direct amination of Grignard reagents (preferably those derived from alkyl chlorides or bromides rather than iodides) by methoxyamine leads to primary amines (reaction 62) . In a similar way. 

The catalytic reduction of nitriles is also frequently employed as a route to primary amines (reaction 98) This involves an imine... 

---