Zinc acetate anhydrous

Note. With silyl ketene acetals, anhydrous zinc bromide (lmol%) is the preferred catalyst. 

The classical experimental conditions of the Erlenmeyer synthesis use anhydrous sodium acetate and acetic anhydride to effect cyclodehydration. However, many other reagent combinations have been used to improve the yield and the stereoselectivity of the reaction. With these aims in mind, zinc acetate,... 

Esterification is effected in the cold in presence of alkali or by heating the alcohol and anhydride together, usually in presence of a dehydrating agent—e.g., fused zinc chloride, anhydrous sodium acetate, etc. Preparation 204.—Mannitol Hexacetate. 

The A-chloro compound 176, obtained from the corresponding meth-oxyamide with f-butyl hypochlorite, was cyclized to l-methoxy-2-indolone 163 by silver carbonate in trifluoroacetic acid (87% yield) (84JA5728), or by other silver or mercury salts (87T2577), and more conveniently by anhydrous zinc acetate in 1,2-dichloroethane (91% yield) (87CL1771). The reaction proceeds through the spiro intermediate 177, followed by both possible 1,2-shifts. 

Different metallic acetates [221] have also been used in acetonitrile, which acts not only as a solvent but also as a dehydrating agent to eliminate the effect of any water produced during the reaction. In this way, the thermodynamic equilibrium could be shifted and the yield of CCs improved. By using 1,2-propene glycol as the reactant (100 mmol) and anhydrous zinc acetate (2.5 mmol) as catalyst in acetonitrile (10ml) with a C02 reaction pressure of 10 MPa, at a reaction temperature of 343 K and a reaction time of 12h, the yield of 1,2-propene carbonate was shown to be 24.2% and the conversion of 1,2-propene glycol 38.9%. 

Suspend 0.5 g of the quinone in 2.5 ml of pure acetic anhydride, and add 0.5 g of zinc powder and 0.1 g of powdered, anhydrous sodium acetate. Warm the mixture gently until the colour of the quinone has largely disappeared and then boil for 1 minute. Add 2 ml of glacial acetic acid and boil again to dissolve the product and part of the precipitated zinc acetate. Decant the hot solution from the zinc acetate and zinc, and wash the residue with 3-4 ml of hot glacial acetic acid. Combine the solutions, heat to boiling, carefully add sufficient water to hydrolyse the acetic anhydride and to produce a turbidity. Cool the mixture in ice, filter off the diacetate of the hydroquinone and recrystallise it from dilute ethanol or from light petroleum. 

To the flask containing dibromocholesterol add 20 mL of ether, 5 mL of acetic acid, and 0.2 g of zinc dust and swirl. In about 3 min the dibromide dissolves after 5-10 min swirling, zinc acetate usually separates to form a white precipitate (the dilution sometimes is such thatno separation occurs). Stir for 5 min more and then add waterby drops (no more than 0.5 mL) until any solid present (zinc acetate) dissolves to make a clear solution. Decant the solution from the zinc into a separatory funnel, and wash the ethereal solution twice with water and then with 10% sodium hydroxide (to remove traces of acetic acid). Then shake the ether solution with an equal volume of saturated sodium chloride solution to reduce the water content, dry the ether with anhydrous sodium sulfate, remove the drying agent, add 10 mL of methanol (and a boiling stone), and evaporate the solution on the steam... 

A procedure for the reductive acetylation of a quinone, a benzanthrone, or an a-diketone is as follows. A suspension of 1 g. of substance in 5-6 ml. of acetic anhydride is treated with 1 g. of zinc dust and 0.2 g. of anhydrous sodium acetate until the colored material has disappeared and the supernatant liquor is colorless or pale yellow, depending upon the purity of the starting material. After short boiling to complete the reaction, acetic acid is added as required to dissolve the product and part of the zinc acetate that has separated, the solution is filtered at the boiling point from zinc and zinc acetate, the residue is washed with hot solvent, and the total filtrate is boiled under a reflux condenser and treated cautiously with sufficient water to hydrolyze the excess acetic anhydride and then to produce a saturated solution. 

Benzoates and/r-nitrobenzoate esters can be used as well as acetates, higher yields being obtained with the former. Yields are in the range 50-95%. Replacement of metallic zinc by anhydrous zinc acetate gives similar results. Ghera discusses the mechanism and stereochemistry of the Serini reaction. He suggests that the catalyst functions as a complexing Lewis acid. 

AMMONIUM DIHYDROGEN PHOSPHATE (7783-28-0) Contact with air slowly forms anhydrous ammonia. Contact with caustics forms anhydrous ammonia gas. Violent reaction with strong oxidizers, potassium chlorate, strong bases. Reacts with antimony(V) pentafluoride, lead diacetate, magnesimn, silver nitrate, zinc acetate. AMMONIUM DISULFATO-NICKELATE (II) (15699-18-0) NiS04(NH4)2S04 jHj0 A weak oxidizer. Aqueous solution is acidic. Reacts violently with carbon dust, potassium, finely divided... 

Sodium acetate anhydrous Sodium acid pyrophosphate Sodium alum Sodium cyanide Sodium hydroxide Sodium polysulfide Tannic acid Triethanolamine Trisodium citrate Zinc Zinc chloride Zinc cyanide Zinc fluoride Zinc sulfate Zinc sulfate monohydrate electroplating activator, ABS Stannic chloride... 

Molybdenum trioxide PEG-90 Sodium phosphate dibasic anhydrous Sodium sulfate Zinc acetate Zirconium naphthenate Zirconium oxide... 

Elemi gum Lead acetate Lead acetate trihydrate Lithium stearate Polymethylhydrosiloxane Potassium alum anhydrous Pyridine Sodium alum Tallow acid 1,2,4,5-Tetrachlorobenzene Tri-m-cresyl phosphate Tri-p-tolyl phosphate Zinc acetate Zinc ricinoleate waterproofing agent mfg. 

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