Zinc, Acetate Compound Powder

Reaction VIH. Action of certain finely divided Metals on Diazonium Compounds in Alcohol or Acetic Anhydride Solution.—This reaction is limited to the preparation of s-diaryl compounds. Copper, zinc, or iron powder may be used, but the former is, on the whole, the most satisfactory, especially when it has been freshly prepared according to Gattermann s... 

The key starting compound is the mono nitro derivative of calix[4]arene 4, which was obtained via a single-step reaction with 10 equivalents of 63% HNO3 in a mixture of dichloromethane and glacial acetic acid in less than 5 min in 94% yield according to the literature method. Compound 4 converted to bisphthalonitrile derivative 5 by the given method in 59% yield. Ball-type ZnPc 6 was prepared from 5 and zinc acetate in 1-pentanol in the presence of DBU. Hexanuclear ball-type ZnPc 8 was obtained by the reaction of 6 with 7 in a mixture of NaOH, MeOH, THF, and activated zinc powder with a yield of 55%. 

The copper sulphide is filtered off and zinc acetate added to the filtrate, the zinc salt of m-arsanilic acid separating out. After filtering and washing, this is boiled with 275 c.c. of water and 160 c.c. of 10 per cent, sodium carbonate solution, the zinc carbonate filtered off, and the solution nearly neutralised with concentrated hydrochloric acid. 13-5 c.c. of glacial acetic acid are added to acidify the solution, and the amino compound is precipitated as a faintly red, crystalline powder. Yield, 65 per cent. It may be purified by dissolving in dilute ammonium hydroxide, boiling with animal charcoal, and reprecipitating with acetic acid. 

Carry out this preparation precisely as described for the a-compound, but instead of zinc chloride add 2 5 g. of anhydrous powdered sodium acetate (preparation, p. 116) to the acetic anhydride. When this mixture has been heated on the water-bath for 5 minutes, and the greater part of the acetate has dissolved, add the 5 g. of powdered glucose. After heating for I hour, pour into cold water as before. The viscous oil crystallises more readily than that obtained in the preparation of the a-compound. Filter the solid material at the pump, breaking up any lumps as before, wash thoroughly with water and drain. (Yield of crude product, io o-io 5 g.). Recrystallise from rectified spirit until the pure -pentacetylglucose is obtained as colourless crystals, m.p- 130-131° again two recrystallisations are usually sufficient for this purpose. 

When an organic compound is heated with a mixture of zinc powder and sodium carbonate, the nitrogen and halogens are converted into sodium cyanide and sodium hahdes respectively, and the sulphur into zinc sulphide (insoluble in water). The sodium cyanide and sodium hahdes are extracted with water and detected as in Lassaigne s method, whilst the zinc sulphide in the residue is decomposed with dilute acid and the hydrogen sulphide is identified with sodium plumbite or lead acetate paper. The test for nitrogen is thus not affected by the presence of sulphur this constitutes an advantage of the method. 

Zinc phthalocyanine (PcZn) is prepared from phthalonitrile in solvents with a boiling point higher than 200 C, e.g. quinoline277,278 or 1-bromonaphthalene,137 or without solvent in a melt of phthalonitrile.83,116 The zinc compound normally used is zinc(ll) acetate or zinc powder. The reaction of zinc(II) acetate with phthalic acid anhydride, urea and ammonium mo-lybdate(VI) is also successful.262 The metal insertion into a metal-free phthalocyanine is carried out in an alcohol (e.g.. butan-l-ol).127,141,290 This reaction can be catalyzed by an alkali metal alkoxide.112,129... 

The thiazine dyes used in the preparation of this type of leuco are obtained through oxidative coupling of phenothiazine with an active methylene compound or an aniline. The reduction of the dye 23 with zinc powder in acetic acid is straightforward.9 Treatment of the leuco 24 with acetic anhydride at 40°C yields a more air stable leuco 25.9 Addition of arylsulfinic acid to thiazine dyes such as 26 produces directly leuco dyes such as 27.Sb... 

The antitrichomonal compound l-methyl-5-nitro-2-(2 -pyrimidyl)imida-zole (97 R = Me, R2 = pyrimid-2-yl) has been shown to be metabolized to the corresponding acetamide (118 R1 = Me, R2 = pyrimid-2-yl, R3 = Me) in both rats and humans (74JPS293). The acetamide (118 R1 = Me, R2 = pyrimid-2-yl, R3 = Me) was also produced synthetically by reduction of a solution of the nitroimidazole (97 R1 = Me, R2 = pyrimid-2-yl) in acetic acid with zinc powder and subsequent treatment of the aminoimidazole (96 R1 = Me, R2 = pyrimid-2-yl) in situ with acetic anhydride to give the acetamide (118 R = Me, R2 = pyrimid-2-yl, R3 = Me) (4%) (74JPS293). 

The tetrasulfo-Pc complexes of a number of metals are made by the urea melt process by heating the powdered metal, or its acetate, with triammonium-4-sulfophthalate, urea, boric acid, and ammonium molybdate. The metals or metal compounds used are those of chromium (III), manganese(II), iron(II), iron(III), cobalt(II), and zinc(II). Selected synthetic examples of sulfo- and other derivatives of metal phthalocyanines are presented below. 

Two examples using azo compounds in allylic amination reactions will be presented in the following. Leblanc et al. have used the more reactive trichloro derivative 82 of DEAD, 81, and found that the ene reaction proceeds at various temperatures and without any Lewis acid catalyst present, for both cyclic and acyclic alkenes to give allyl amines in good yields. The reaction of the alkene 85 with 82 gave the allylic aminated compound 86 in 85 % yield (trans. cis = 85 15) (Eq. (21)) [53f. The allyl amine 87 was formed in good yield after treatment with a suspension of zinc powder in acetic acid solution. 

A very dangerous fire and moderate explosion hazard when exposed to heat or flame can react vigorously with oxidizing materials. Warning pyrophoric in air. Mixtures with nitrogen oxide explode above 50°C. Violent reaction with zinc + transition metal halides (e.g., cobalt halides, rhodium halides, ruthenium halides). Mixtures with acetic acid + water produce a pyrophoric powder. To fight fire, use water, foam, CO2, dr " chemical. See also CARBONYLS and IRON COMPOUNDS. 

These condensation compounds are not easily reduced, the follomng reagents being without effect zinc and acetic or hydrochloric acid aluminium powder and sodium hydroxide sodium and alcohol. 

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