Palladium hydroxide on charcoal

To a 5 liter Parr apparatus (special pressure reaction vessel commercially available) place 4400 milliliters of acetonitrile, 300 grams of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (prepared in step 1), 1000 milliliters of acetic anhydride, 75 grams of 20% palladium hydroxide on charcoal catalyst (commercially available), and 8.4 grams of bromobenzene. Then turn the machine on, and shake the mixture at 50 psi for 36 hours at 10 Celsius. After 36 hours, remove the reaction mixture from the Parr apparatus, and then filter to remove the precipitated product. The precipitated product also contains the charcoal catalyst (save the filtered reaction mixture). After filtration, mix the filtered-off solids with 10 liters of boiling chloroform, and then stir the mixture for 20 minutes. Then filter the mixture hot to remove insoluble impurities. After which, recrystallize the product from the chloroform, and then vacuum dry or air-dry the product. Next, add the dry product to 300 milliliters of acetonitrile, and then stir the mixture for ten minutes at room temperature. Afterwards, filter the mixture to collect the insoluble product, and then vacuum dry or air-dry the product. 

Palladium hydroxide on charcoal, Pd(OH)2/C. This catalyst was developed by... 

A cold soln. of 2-oxobutyric acid in ethanol treated with L-(—)-a-methylhenzyl-amine in the same solvent, 10%-Pd-on-charcoal added, hydrogenated 10 hrs. at 30 /50 p.s.i. until 1 mole of has been absorbed, the catalyst removed by filtration, the filtrate coned., aq. 30%-alcohol and palladium hydroxide-on-charcoal added, then hydrogenated at 25 /50 p.s.i. until Hg-uptake ceases L-butyrine. Y 75.9-84.9% excess of enantiomorph 81.4%.— Debenzylation with other catalysts was not successful. Asym. induction occurs during reduction of the azomethine and debenzylation can be performed with little or no loss of configurational integrity. The configuration of the amino acids is the same as that of the a-methylbenzylamine from which it is derived. The magnitude of the induced asymmetry depends on the substrate and the catalyst. F. e. s. R. G. Hiskey and R. G. Northrop, Am. Soc. 83 4798 (1961) asym. synthesis of amino acids s. a. J. G. Sheehan and R. E. Chandler, Am. Soc. 83, 4795 (1961). 

Palladium-on-charcoal, 274 Palladium hydroxide on barium sulfate, 218 Paraformaldehyde, 284 Pentacene, 132... 

A similar effect was obtained by polymerization and deprotection of 9-phenyl-2,4,8,10-tetraoxaspiro[5,5]undecan-3-one. The poly (ester-carbonate) s were synthesized by the ROP of l-LA and functionalized pentaerythritol-based carbonate monomer with diethyl zinc as a catalyst (Scheme 70). The protecting ben-zylidene groups in the copolymer poly(L-LA-co-9-phenyl-2,4,8,10-tetraoxaspiro[5,5]undecan-3-one) were removed by hydrogenation with palladium hydroxide on activated charcoal as a catalyst to give a functional copolymer, poly(L-LA-co-5,5-bis (hydroxymethyl)-l,3-dioxan-2-one), containing pendant primary hydroxyl groups. The cell morphology and viability on a... 

B. Hydrogenolysis of the Phenolic Ether Biphenyl. To a solution of 10 g. (0.032 mole) of the product from Part A in 200 ml. of benzene is added 2 g. of 5% palladium-on-charcoal, and the mixture is shaken with hydrogen in a Parr apparatus at 40 p.s.i. and 35-40° for 8 hours (Note 3). The mixture is filtered, and the insoluble residue is washed with three 100-ml. portions of hot ethanol (Note 4). The filtrates are combined, and the solvent is removed by means of a rotary evaporator at 60° (12 mm.) to leave a solid residue. The product is dissolved in 100 ml. of benzene, and 100 ml. of 10% sodium hydroxide solution is added. The mixture is shaken, and the layers are separated. The aqueous layer is extracted with 100 ml. of benzene, and the original benzene layer is washed with 100 ml. of water (Note 5). The benzene solutions are combined and dried over magnesium sulfate. Removal of the benzene by distillation yields 4.0-4.7 g. (82-96%) of biphenyl as a white powder, m.p. 68-70° (Note 6). The infrared spectrum is identical with that of an authentic sample, and a purity of at least 99.5% was indicated by gas chromatography analysis. 

Glyoxal, Benzylamine, Formic acid. Acetonitrile, Acetic anhydride. Palladium on charcoal, Bromobenezene, Chloroform, Sulfolane, Nitrosonium tetrafluoroborate. Ethyl acetate Triethylbenzyl ammonium chloride. Methylene chloride. Sodium hydroxide. Methanol... 

To prepare palladium on charcoal (5% Pd), heat a solution of 1.7 g of palladium chloride (1) in 1.7 ml of concentrated hydrochloric acid and 20 ml of water on a water bath for 2 hours or until solution is complete, and add this to a solution of 30 g of sodium acetate trihydrate in 200 ml of water contained in a 500-ml hydrogenation flask. Add 20 g of acid-washed activated charcoal (2) and hydrogenate in an atmospheric hydrogenation apparatus (Fig. 2.63(a)) until absorption ceases. Collect the catalyst on a Buchner funnel and wash it with five 100 ml portions of water and suck as dry as possbile. Dry the catalyst at room temperature (3) over potassium hydroxide pellets or anhydrous calcium chloride in a vacuum desiccator. Powder the catalyst (about 20 g) and store in a tightly stoppered bottle. 

Hydrogenolysis of the benzyl group of 9-benzyloxy-4//-pyrido[ 1,2-a]pyrimidin-4-ones 336 in ethanol over 10% palladium-on-charcoal under pressure of hydrogen (3 atm), or in the presence of cyclohexene and 10% palladium hydroxide, afforded 9-hydroxy derivatives 337 in 25-30% and 78% yield, respectively (89TL1529 91JHC1287). 

Potassium hydroxide Hydrogen chloride Palladium on charcoal Morpholine Sodium hydroxide... 

P-Amfno acids. Chiral enamines (1) are hydrogenated by 10% palladium hydroxide catalyst on charcoal to )3-amino acids (2) in optical purity of 7-28%. Optical yields are lower if the enamines are reduced with sodium cyanoborohydride. The two methods lead to opposite configurations of 2. 

Halogens on a cyclopropane ring can be removed without hydrogenolysis of the ring itself. The selective removal of one bromine from 1,1-dibromo-cyclopropanes occurred over palladium on charcoal or platinum oxide in methanolic potassium hydroxide at room temperature and atmospheric pressure. Complete debromination resulted from the use of Raney nickel under the same conditions (Eqn. 20.56). 31... 

The commercial catalyst used for hydrogenation was a palladium on charcoal catalyst (type 37), manufactured by Johnson Matthey (UK)) with metal content 4.89% and supplied as powder. The Pd metal was d osited on the exterior sur ce of the charcoal The Pd/Ii02 catalyst was prepared using sodium tetrachloropalladate (II), supplied by Johnson Matthey (UK) and titanium dioxide, firom Degussa (Germany). The hydrogen gas was supplied by BOC (UK), with >99.98% purity and was used directly fi om cylinder. The reactant, butyne-l,4-diol 99%, was procured firom Aldrich (UK) and water and 2-propanol obtained firom Fisons (UK), were used as solvents. Additives such as lead acetate, quinoline, thiophene and triethyl phosphite were supplied by Aldrich (UK) and cupric acetate, zinc su hate, ferric nitrate and potasaum hydroxide were provided by Fisons (UK). 

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