Diamines, from addition

A comparison of the hydrolytic stability of several sulfonated six-membered ring polyimides was previously investigated. Membranes were placed in distilled water at 80 °C until a loss of mechanical properties was observed. Improvements in membrane stability were observed for polymers with lower degrees of sulfonation (lower lEC) and for random copolymers, as opposed to block or sequenced copolymers. Additionally, the flexibility of the sulfonated diamine in the polymer structure was shown to play an important role in stability. By simply changing the sulfonated diamine from the rigid 4,4 -diamino-... 

Cyclopropaniminium salts have been prepared in solution from cyclopropane-1,1-diamines by addition of methyl fluorosulfate, - bromine in liquid sulfur dioxide or dimethylchloronium tetrafluoroantimonate in liquid sulfur dioxide. Bicyclo[4.1.0]heptaniminium salts were obtained in fluorosulfonic acid at — 60 °C from a bicyclo[4.1.0]heptanone aminal or hemiaminal precursor or by the reaction of the corresponding aminal and methyl fluorosulfate in chloroform. A free cyclopropaniminium ion in solution also was assumed to be generated by the interaction of cyclopropanone hemiaminal with titanium(IV) chloride at — 78°C in di-chloromethane. ... 

One of the key parameters defining the mechanical properties of the cured epoxy is the crosslink density. In a diepoxy fully cured with a diamine, if additional effects such as side reactions are neglected, each primary amine group is expected to react with two epoxide groups. Branched crosslinks result from this situation. With the chemical functionalities /a = 4 and /e = 2 of the diamine and the diepoxy molecules, respectively, the amine/epoxy mixing ratio, r, is given by Eq. (1), where and Ng denote the respective numbers of moles [10]. 

Additional catalyst development identified the positive effect of 1,2-diamines as additives in the (BlNAP)Ru(OAc)2-catalyzed enantioselective hydrogenations of ketones [24], This discovery ultimately led to the synthesis of a class of (diphosphine) Ru(diamine)X2 (X = H, halide) compounds [25] (Figure 4.1) which have emerged as some of the most active and selective hydrogenation catalysts ever reported [26]. Mechanistic studies by Noyori [14] and Morris [27] have established bifunctional hydrogen transfer to substrate from the cis Ru-H and N-H motifs and identified the importance of ruthenium hydridoamido complexes for the heterolytic splitting of H2. This paradigm allows prediction of the absolute stereochemistry of the chiral alcohols produced from these reachons. 

Preparations of poly-p-phenyleneterephthalamide by polycondensations with N-silylated diamine proceed more rapidly than with the parent diamine.In addition, the products have higher molecular weights than a similar commercial material made from the parent diamine and sold under the trade name of Kevlar. 

In 2000, Roland and Mangeney developed a diastereoselective synthesis of tert-butyl-1,2-diamines from the addition of tert-butylmagnesium chloride to... 

Without additional reagents Preferential nucleophilic addition to carbon-nitrogen double bonds 1,1-Diamines from cyclic azomethines... 

In addition to their antiknock properties, organic lead compounds possess bactericidal properties and motor fuels with lead are known to inhibit bacterial growth during storage in contact with water. With the disappearance of lead-based compounds, it is necessary to incorporate biocides from the cyclic imine family, (piperidine, pyrrolidine, hexamethyleneimine), alkylpropylene diamines or imidazolines (Figure 9.2). 

The above diamines can alternatively be identified as their diacetyl derivatives. Heat under reflux 0 5 g. of the diamine with 3 ml. of acetic acid—NaOH solution will cause the separation of the diacetyl derivative. Recrystallise from ethanol. M.ps. of the diacetyl derivatives of 0-, m-, and />-phenylene diamine are 185 , 191 , and 304 respectively (p. 551). 

Polymers from either of these homologous series can be made to predominate by usiag a small excess of the diamine or diacid, respectively. In addition to these linear polymers, cycHc oligomers are also formed, though ia this case n... 

Lewis acids, such as the haUde salts of the alkaline-earth metals, Cu(I), Cu(II), 2inc, Fe(III), aluminum, etc, are effective catalysts for this reaction (63). The ammonolysis of polyamides obtained from post-consumer waste has been used to cleave the polymer chain as the first step in a recycle process in which mixtures of nylon-6,6 and nylon-6 can be reconverted to diamine (64). The advantage of this approach Hes in the fact that both the adipamide [628-94-4] and 6-aminohexanoamide can be converted to hexarnethylenediarnine via their respective nitriles in a conventional two-step process in the presence of the diamine formed in the original ammonolysis reaction, thus avoiding a difficult and cosdy separation process. In addition, the mixture of nylon-6,6 and nylon-6 appears to react faster than does either polyamide alone. 

In addition to the mono- and dialkylamines, representative stmctures of this class of surfactants include /V-alkyltrimethylene diamine, RNH(CH2)3NH2, where the alkyl group is derived from coconut, tallow, and soybean oils or is 9-octadecenyl, 2-aLkyl-2-imidazoline (3), where R is heptadecyl, heptadecenyl, or mixed alkyl, and l-(2-aniinoethyl)-2-aLk5l-2-imidazoline (4), where R is heptadecyl, 8-heptadecenyl, or mixed alkyl. 

The manufacture of hexamethylenediamine [124-09-4] a key comonomer in nylon-6,6 production proceeds by a two-step HCN addition reaction to produce adiponittile [111-69-3] NCCH2CH2CH2CH2CN. The adiponittile is then hydrogenated to produce the desired diamine. The other half of nylon-6,6, adipic acid (qv), can also be produced from butadiene by means of either of two similar routes involving the addition of CO. Reaction between the diamine and adipic acid [124-04-5] produces nylon-6,6. 

A number of BMI resias based on this chemistry became commercially available through Rhc ne Poulenc for appHcation ia priated circuit boards and mol ding compounds and Rhc ne Poulenc recognized the potential of bismaleimides as building blocks for temperature-resistant thermoset systems. The basic chemistry, however, was not new, because the Michael addition reaction had been employed by Du Pont to obtain elastomeric reaction products from bismaleimides and Hquid polymeric organic diamines (15). 

The kinetics of the hydrolysis of some imines derived from benzophenone anc primary amines revealed the normal dependence of mechanism on pH with ratedetermining nucleophilic attack at high pH and rate-determining decomposition of the tetrahedral intermediate at low pH. The simple primary amines show a linear correlation between the rate of nucleophilic addition and the basicity of the amine Several diamines which were included in the study, in particular A, B, and C, al showed a positive (more reactive) deviation from the correlation line for the simple amines. Why might these amines be more reactive than predicted on the basis of thei ... 

Acetylene is passed for 1 hr through a mixture consisting of 0.5 g (72 mg-atoms) of lithium in 100 ml of ethylene-diamine. A solution prepared from 1 g (3.5 mmoles) of rac-3-methoxy-18-methylestra-l,3,5(10)-trien-I7-one and 30 ml of tetrahydrofuran is then added at room temperature with stirring over a period of 30 min. After an additional 2 hr during which time acetylene is passed through the solution the mixture is neutralized with 5 g of ammonium chloride, diluted with 50 ml water, and extracted with ether. The ether extracts are washed successively with 10% sulfuric acid, saturated sodium hydrogen carbonate and water. The extract is dried over sodium sulfate and concentrated to yield a solid crystalline material, which on recrystallization from methanol affords 0.95 g (87%) of rac-3-methoxy-18-methyl-17a-ethynyl-estra-l,3,5(10)-trien-17jB-ol as colorless needles mp 161°. 

Though dental afflictions constitute a very significant disease entity, these have received relatively little attention from medicinal chemists. (The fluoride toothpastes may form an important exception.) This therapeutic target Is, however, sufficiently Important to be the focus of at least some research. A highly functionalized piperazine derivative that has come out of such work shows prophylactic activity against dental caries. Condensation of the enol ether 1 of thiourea with ji-pentylisocyanate gives the addition product 1J. Reaction of this with diamine 78, derived from piperazine, leads to substitution of the methylthio moiety by the primary amine, in all likelihood by an addition-elimination sequence. There is thus obtained ipexidine (79). ... 

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