Ammonium acetate intermediates

Ammonium acetate and sodium methoxide are effective catalysts for the ammonolysis of soybean oil (49). Polyfunctional amines and amino alcohols such as ethylenediamine, ethanolamine, and diethanolamine react to give useful intermediates. Ethylenediamine can form either a monoamide or a diamide depending on the mole ratio of reactants. With an equimolar ratio of reactants and a temperature of >250° C, a cyclization reaction occurs to give imidazolines with ethylenediamine (48) ... 

Treatment of a-hydroxy-ketones or -aldehydes with ammonium acetate (65BSF3476, 68BSF4970) results in the formation of dihydropyrazines, presumably by direct amination of the hydroxyketone followed by self-condensation (79AJC1281). Low yields of pyrazines have been noted in the electrolysis of ketones in admixture with KI and ammonia, and again it appears probable that the a-aminoketone derived by way of the a-iodoketone is the intermediate (69CI(L)237>. 

Yadav and Kapoor <2003TL8951> reported on a microwave-assisted ring closure leading to novel thiazolo[l,3,5]-triazines, as shown in Scheme 36. This three-component one-pot procedure started from the thiazolyl Schiff base 230, to which ammonium acetate and an aldehyde was added. In the first step, the azomethine moiety of the Schiff base reacted with ammonia to give the zwitterionic first intermediate 231, which underwent deprotonation to the amine 232, and, finally, reaction of this second intermediate with the aldehyde involving the ring-closure step afforded the product 233. It is important to emphasize that the MW-assisted technique ensured high yields (76-88%)... 

A similar heterogeneous photocatalytic system was applied for the study of the decomposition of the anthraquinone dye, Acid blue 25 (AB25). The chemical structure of the dye and those of the first intermediates tentatively identified by HPLC-MS are shown in Fig. 3.55. RP-HPLC-DAD analysis of AB25 was carried out in a C4 column (250 X 4 mm i.d. particle size 5 //m) at ambient temperature. The isocratic mobile phase was composed of ACN (solvent A)-water (pH adjusted to 4.5 with acetic acid and ammonium acetate) (42 58, v/v). 

Thus, RP-HPLC-MS has been employed for the analysis of sulphonated dyes and intermediates. Dyes included in the investigation were Acid yellow 36, Acid blue 40, Acid violet 7, Direct yellow 28, Direct blue 106, Acid yellow 23, Direct green 28, Direct red 79, Direct blue 78 and some metal complex dyes such as Acid orange 142, Acid red 357, Acid Violet 90, Acid yellow 194 and Acid brown 355. RP-HPLC was realized in an ODS column (150 X 3 mm i.d. particle size 7 /.an). The composition of the mobile phase varied according to the chemical structure of the analytes to be separated. For the majority of cases the mobile phase consisted of methanol-5 mM aqueous ammonium acetate (10 90, v/v). Subsituted anthraquinones were separated in similar mobile phases containing 40 per cent methanol. The flow rate was 1 ml/min for UV and 0.6 ml/min for MS detection, respectively. The chemical structure of dye intermediates investigated in this study and their retention times are compiled in Table 3.28. It was found that the method is suitable for the separation of decomposition products and intermediates of dyes but the separation of the original dye molecules was not adequate in this RP-HPLC system [162],... 

Grumbach et al. [100] recommended the use of acetonitrile with bare silica columns, with concentration not greater than 95% or less than 70%. At least 5% of the mobile phase should be water to allow for the formation of the aqueous layer and to allow solubility of buffer, if one is used. In some cases, methanol can be used to form the polar layer. It was noted that while bare silica can be used at pH < 1 (no bonded ligands to hydrolyze, as in RP-HPLC) it is more susceptible to dissolution at intermediate pH (presumably since it not protected by a C18 layer), and should not be used above pH 6. Buffers such as ammonium acetate at pH 5 and ammonium formate at pH 3 were recommended at 5-20 mM concentrations. They reported the elution strength of various solvents using silica and HlLlC conditions as... 

Chemical/Physical. The estimated hydrolysis half-life of acetonitrile at 25 °C and pH 7 is >150,000 yr (Ellington et al., 1988). No measurable hydrolysis was observed at 85 °C at pH values 3.26 and 6.99. At 66.0 °C (pH 10.42) and 85.5 °C (pH 10.13), the hydrolysis half-lives based on first-order rate constants were 32.2 and 5.5 d, respectively (Ellington et al., 1987). The presence of hydroxide or hydronium ions facilitates hydrolysis transforming acetonitrile to the intermediate acetamide which undergoes hydrolysis forming acetic acid and ammonia (Kollig, 1993). Acetic acid and ammonia formed react quickly forming ammonium acetate. 

Faggi et al. describes the synthesis of a 1,6-dihydro-6-oxopyrazine-2-carboxylic acid derivative via the Ugi four-component reaction (Scheme 8) [28]. Arylglyoxals 44, an amine 45, benzoylformic acid 46, and an isocyanide 47 afforded the Ugi intermediate 48, which was cyclized in a [5+1] fashion with ammonium acetate to give the final product 49 in good yields. 

The tetraethylammonium-Beta (TEA-3) zeolites used in this work have been synthesized following the procedure described in the literature (5). Samples with Si/Al ratios between 7 and 106 (as measured by chemical analysis) and crystallite sizes in the range of 0.2-0.9 ym (as measured by scanning microscopy) were obtained. The H-form of these zeolites was prepared in the following way the TEA-3 samples were heated at 550 C for 3 hours by slowly increasing the calcination temperature (5°C min l), with one-hour intermediate steps at 350 and 450 C. After this treatment all TEA molecules had been removed from the zeolite (as monitored by IR spectroscopy). In a second step, the zeolite was exchanged with 1 M ammonium acetate solution and then heated at 550°C for 3 hours as described. 

Z-Pyrans are transformed to the corresponding 7t-isoelectronic 1,4-dihy-dropyridine derivatives by ammonia,2,37,68,69 ammonium acetate,76,440,841 primary amines,37,62,68,442 hydroxylamine,37 arylhydrazines,3,3,3 urea,440 and thiourea.440 The open-chain intermediates are rarely isolated.62... 

Some nucleophiles open the pyrylium ring to give intermediates which are capable of spontaneous or add-induced cyclization to a new ring. The conversion of pyrylium salts into pyridines is the most thoroughly studied example and was first described in 1911 (B-64MI22300). Ammonia, ammonium acetate or carbonate react with pyrylium salts such... 

Automated HPLC methods were developed for the determination of subsidiary dyes, intermediates, and side reaction products of erythrosine. Peeples and Heitz (154) described a reverse-phase HPLC method to monitor the purity of erythrosine and a series of xanthene dyes involving a yuBondapak Cl 8 column and mixtures of methanol and ammonium acetate buffer. 

In the case of terpyridine and acridine derivatives, the bis(methylamines) are the most convenient intermediates. Substituted 4/-phenyl-2,2/ 6/,2"-terpyridines were prepared by reacting (ii)-propenons and iV-[2-(pyrid-2 -yl)-2-o octln l p ridinium iodide with ammonium acetate in acetic acid or in methanol. The terminal pyridine moieties were oxidized with 3-chloroperbenzoic acid to iV, A" -dio idcs followed by modified Reisserty-Henze reaction to obtain 6,6"-dicarbonitriles. The bis(methylamines) were obtained by reduction of the 6,6"-dicarbonitriles withborane (scheme 8 (Mukkala et al., 1993)). 

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