Secondary amine reaction

Summary New lyophilic cationic silicone surfactants have been synthesized by direct quatemization of halogenated siloxanyl precursors or by transformation of these precursors into tertiary amines with a subsequent quatemization step. After transformation of the precursors into secondary amines, reaction with maleic anhydride and neutralization, new anionic products were obtained. 

The synthesis of 1,3-selenazoles from A -phenylimidoyl isoselenocyanates has been reported. N-phenylimidoyl isoselenocyanates 94 are prepared from N-phenylbenzamides 92. Treatment of 92 with thionyl chloride affords N-phenylbenzimidoyl chlorides 93, which yield imidoyl isoselenocyanates 94 on reaction with potassium isoselenocyanate. The imidoyl isoselenocyanates 94 were transformed into selenoureas 95 with either ammonia or primary or secondary amines. Reaction of 95 with an activated bromomethylene compound such as bromoacetophenone in the prescence of a base gave the 1,3-selenazole 97 via the salt 96 <00HCA1576>. 

Additional NMR information may be useful in difficult enantiomer analyses of alcohols, thiols, and primary and secondary amines. Reaction 32 illustrates the process for a chiral primary amine, RNIF, undergoing N-substitution with chiral reagent 185. Besides the 31P NMR spectra of the diasteroisomers 186, also 1H, 13C and 19F spectra may be taken. Addition of sulfur or selenium to the NMR tube will afford diasteroisomers 187, for which the corresponding spectra can also be taken397. 

Originally reported in 1961,8 the TMSN3-modified Ugi reaction involves condensation of an appropriately substituted aldehyde or ketone with a primary or secondary amine. Reaction of the Schiff base with an... 

Newcomb and coworkers have very elegantly demonstrated that N-hydroxypyridine-2-thione carbamates lc (PTOC carbamates, X = NR2) are directly analogous to the A-hydroxy-pyridine-2-thione esters la. They can be prepared readily from primary and secondary amines. Reaction of these carbamates in a radical chain process gives carbamoyl radicals that decarboxylate to give aminyl radicals, Scheme 40.66 71 In the... 

King and Gill have been studying the reaction of alkyl 2,2,2-trifluoroethanesulfonate esters (tresylates) (308) in aqueous base (pFI>9) in the presence of a primary or secondary amine. Reaction with hydroxide is foimd to be a reversible ElcB process and reaction with water is the normal sulfonic ester hydrolysis. 

Tertiary Amines.—In the tertiary amines there is no remaining ammonia hydrogen therefore, neither the primary nor secondary amine reactions can take place. The fact is that tertiary amines do not react with nitrous acid at all. We thus have a reaction which enables us to distinguish between primary, secondary and tertiary amines. Writing these reactions together we have... 

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)... 

In the case of phenol, with the free para position, due to the interaction between the phenolic group (acidic) and the aminic nitrogen (basic) of the amino alcohol, the ortho position is occupied first [9]. After the synthesis of Mannich bases, the water resulting from the reaction and the water from the aqueous solution of formaldehyde is distilled under vacuum, at 90-125 °C (preferably in the range 90-100 °C). A low range of distillation temperatures is preferred in order to avoid the tendency of the Mannich base to condensate to superior oligomers (with 2-3 aromatic nuclei), which increase substantially the viscosity of Mannich base and, of course, of final Mannich polyol. The mechanism of the Mannich reaction is considered to be a two-step mechanism. In the first step the reaction between formaldehyde and the primary or secondary amine (reaction 15.2) takes place, with the formation of an immonium cation [7-9, 22, 23]. 

Deamination of primary and secondary amines. Reaction of cyclohexylamine, nitrogen tetroxide, and DBU (or DBN) in ether at -78° furnishes cyclohexyl nitrate in 757 yield. In the absence of the base, a mixture of the nitrate, cyclo-hexanol, and another product is obtained in about 507 yield. The new conditions are also applicable to primary alkyl amines n-octylamine / -octyl nitrate (817o yield). The reaction proceeds with retention of configuration in the case of 3a- and 3 -aminocholesterol. 

Theoretical treatment of this polymerization is difficult because of the presence of both primary and secondary amine reactions as well as tertiary amine catalyzed epoxy homopolymerization. To obtain kinetic and viscosity correlations, empirical methods were utilized. Various techniques that fully or partially characterize such a system by experimental means are described in the literature ( - ). These methods Include measuring cure by differential scanning calorimetry, infra-red spectrometry, vlsco-metry, and by monitoring electrical properties. The presence of multiple reaction mechanisms with different activation energies and reaction orders (10) makes accurate characterizations difficult, but such complexities should be quantified. A dual Arrhenius expression was adopted here for that purpose. 

This chapter discusses the intenelation between mechanical properties, molecular mobility and chemical reactivity of curing epoxy-amine thermosets, illustrated by examples of how the charge recombination luminescence (CRL), heat-capacity and rate constants of chemical reactions are influenced by gelation and vitrification during isothermal cure. A comparison of dynamic mechanical, CRL and modulated temperature DSC data shows that vitrification is accompanied by an increase in CRL and a decrease in heat-capacity, and that the heat-capacity and CRL continue to change after the viscoelastic properties have levelled out. It is also shown how the rate constant of an intermolecular secondary amine reaction, measured by near infirared spectroscopy, is sensitive to gelation, whereas the intramolecular rate constant instead is sensitive to vitrification. 

Figure 5. Effective values of rates for intermolecular (K4) and intramolecular (K5) secondary amine reaction versus cure time for TGDDM/DDS.

Under what conditions might such a scheme be realized of interaction of quaternary ammonium salt with the epoxide compormd in the presence of primary or secondary amines Reaction proceeding by this mechanism is possible when the amine proton-donor reagents are exhausted and when there is essentially no water. Thus, depending on the state in which the quaternary salt is introduced to the reaction system (as crystalline salt or as aqueous solution), it can act as a reactive or an inert surface-active additive. 

The potential of MTDSC for the real-time monitoring of reaction-induced phase separation is demonstrated with the cure of an epoxy— aniline-polyethersulphone (PES) mixture [80,104], The epoxy-aniline system allows following the isothermal cure accurately above and below goo (94°C), Choosing an isothermal cure temperature below will provoke a combination of phase separation of a PES-rich phase and vitrification of the epoxy-aniline matrix. Figure 2,17 shows the quasi-isothermal cure at 80°C for both modified and unmodified epoxy-aniline systems. The effect of primary and secondary amine reactions is seen as a positive A Cp,react- In the unmodified system, vitrification is seen after 91% conversion as a stepwise... 

Primary and secondary amines Reaction with 1-fluoro-2,4-dinitrobenzene Reaction with 1,2-naphthoquinone-4-sulfonate lO- -iQ- moir A fluoride-selective electrode is used. Measurement of color formation in the presence of Triton X-100... 

To gain further insight into the reactions of alkenyl azlactones with secondary amines, reaction of 2 with a variety of simple amines was studied. Table 3 lists the results as the ratio of Michael addition to ring-opening as estimated by 100 MHz H-NMR. As can be seen from the... 

Diphenyl-l,3-dithiolium perchlorate, which with tertiary aliphatic amines yields the bis-l,3-dithiole derivative (69), gives 2-dialkylamino-l,3-dithioles (70) on treatment with secondary amines. Reaction with primary amines can give similar products (70 R = H) but normally leads to the bis-l,3-dithiolylamines (71). With primary alcohols the perchlorate is converted into 2-alkoxy-l,3-dithioles the reaction fails with... 

Several peracetylated 2-deoxy-2-thioureido-P-D-glucopyranoses have been prepared by treating 2-deoxy-2-isothiocyanato-P-D-glucopyranose tetra-acetate with primary or secondary amines. Reaction of 2-amino-2-deoxy- D-glucopyranose tetra-acetate (184) with triphenylphosphine and carbon tetrachloride in dichloro-methane (the Appel reaction) gave the triphenylphosphonioamino salt (185), which yielded the phosphinimine (186) on treatment with triethylamine and the iV-methyl-aminotriphenylphosphonium iodide (187) on further treatment of (186) with... 

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