Ammonia-aluminum trichloride

Another examination involves a synthesis of thienobenzazepines based on the formation of key intermediate 6 prepared according to the method of McDowell and Wisowaty (Scheme 6.2). ° Selective reduction of this intermediate using zinc dust in 28-30% ammonia solution afforded the benzoic acid 7, which upon subsequent Curtius rearrangement and aluminum trichloride-mediated cyclization furnished the oxo-azepine 8. While this synthetic approach gave the tricycle in a few synthetic transformations, many of the same concerns as above exist when considering large scale preparation of 8 the use of large amounts of zinc, sodium azide, and aluminum trichloride. 

The nucleophilic addition of alcohols [130, 204-207], phenols [130], carboxylates [208], ammonia [130, 209], primary and secondary amines [41, 130, 205, 210, 211] and thiols [211-213] was used very early to convert several acceptor-substituted allenes 155 to products of type 158 and 159 (Scheme 7.25, Nu = OR, OAr, 02CR, NH2, NHR, NRR and SR). While the addition of alcohols, phenols and thiols is generally carried out in the presence of an auxiliary base, the reaction of allenyl ketones to give vinyl ethers of type 159 (Nu = OMe) is successful also by irradiation in pure methanol [214], Using widely varying reaction conditions, the addition of hydrogen halides (Nu= Cl, Br, I) to the allenes 155 leads to reaction products of type 158 [130, 215-220], Therefore, this transformation was also classified as a nucleophilic addition. Finally, the nucleophiles hydride (such as lithium aluminum hydride-aluminum trichloride) [211] and azide [221] could also be added to allenic esters to yield products of type 159. 

Several supports were studied, including so-called poly-alumazane, which is prepared by subsequent treatment of silanol rich silica with aluminum trichloride and ammonia. With the resulting support palladium catalysts with very high dispersion were obtained. 

Preparation of polv-alumazane. Poly-alumazane (denoted as Al-N) was prepared according to literature data8 with some minor alterations. 20 g aluminum trichloride (AlCl-j) (Merck, PA) was dissolved in 500 ml nitromethane (Merck) in a 1 1 three-necked flask and 20 g silica (C 560, 200-500 /im, Uetikon, Switzerland, dried in vacuum at 120 °C) was added. After impregnation of the silica with AlClj the silica was treated with gaseous ammonia, followed by heating in nitrogen gas to 500 °C. The poly-alumazane was further prepared according to literature. 

A mixture of 59.5 g (0.2 mol) 2-(4-methoxybenzyl)-l,3,3-trimethyl-4-piperidone hydrochloride and 53.8 g (0.4 mol) of aluminum trichloride and 54.0 g of nitrobenzene in 1500 ml of dry benzene are boiled under reflux for 1 h. After cooling the reaction mixture is extracted with 750 ml 4 N sodium hydroxide solution, the temperature being maintained below 35°C. The organic phase is separated and extracted with 750 ml 1 N hydrochloric acid. The acid aequeous phase is rendered alkali by the addition of 100 ml 25% ammonia and extracted three times with 250 ml chloroform. The collected chloroformic phases are dried with sodium sulfate and evaporated under reduced pressure. The residue, 46.7 g, is converted into the hydrochloride by reaction with iso-propanol/HCI and crystallized from a mixture of methanol and ethylacetate. 44.6 g of the 5-hydroxy-2 -methoxy-2,9,9-trimethyl-6,7-benzomorphan hydrochloride are obtained, melting point 233-236° C (dec.). 

So far, our discussion of reactions has been restricted to organic molecules. However, all the main ideas are applicable to inorganic systems as well. Thus, for example, the formation of inorganic donor-acceptor complexes may be conveniently described by the HOMO-LUMO concept. A case in point is the formation of the aluminum trichloride-ammonia complex (cf. Figure 3-15). This complex can be considered to result from interaction between the LUMO of the acceptor (A1C13) and the HOMO of the donor (NH3). 

CHLOROMETHANE (74-87-3) CH3CI Highly flammable gas [explosion limits in air (vol %) 8.1 to 17.2 flashpoint <32°F/<0°C autoignition temp 1170°F/632°C Fire Rating 4]. Moisture causes decomposition. Violent reaction with strong oxidizers, acetylene, anhydrous aluminum trichloride, ammonia, amines, ethylene, fluorine, interhalogens magnesium, potassium, powdered aluminum or zinc, sodium, and... 

Figure 3-22. The uncomplexed ammonia and aluminum trichloride molecules and the triangular antiprismatic shape of the HjN-AlCl, donor-acceptor complex.

When AIN was introduced for electronic packaging applications in 1985 it was considered inconsistent in properties. This inconsistency was due to problems with the AIN powders used to make sintered products. The powders were made by either of two methods direct nitridation of aluminum metal in a nitrogen gas atmosphere or carbothermal reduction of alumina, which involves the decomposition of the reaction product of aluminum trichloride with ammonia. The first process was cheaper, but the resultant powders were not especially well suited to materials for electronic applications. The carbothermal process produces powders of greater uniformity and purity, with greater control over size and shape, than the nitridation process, and is the more widely used process today." ... 

ANTIMONY TRICHLORIDE (10025-91-9) Cl3Sb Contact with moist air forms corrosive hydrogen chloride fumes. Contact with water, steam forms hydrochloric acid and toxic antimony oxychloride. Aqueous solution is an acid. Violent reaction with ammonia, strong bases, amines, amides, and inorganic hydroxides alkali metals finely divided aluminum potassium, sodium. Attacks metals, releasing flammable... 

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