Palladium catalysts charcoal catalyst

B. 2,2,7,7,12,12,17,17-Octemfi<%Z-21,22,23,24-t tfstainless-steel shaking autoclave is charged with 4.0 g. (0.0092 mole) of the tetraoxaquaterene from Part A, 200 ml. of ethanol, and 400 mg. of 5% palladium on charcoal catalyst (Note 6). The autoclave is filled with hydrogen at an initial pressure of 170 atm. and heated with shaking for 4 hours at 105 . Catalyst and a white solid are removed by filtration (Note 7), the solid is dissolved in 100 ml. of warm chloroform, the solution is filtered, the chloroform is evaporated, and the white solid which is obtained is dried under reduced pressure at 60° (Note 8). The tetraoxaperhydroquaterene is obtained as a white solid, m.p. 204-209 (Note 9), in a yield of 2.85-2.97 g. (69-72%). 

Catalyst obtained from Engelhard Industries was used. The submitters used 200 mg. of Fluka 10% palladium on charcoal catalyst with 5 g. of starting material in 250 ml. of ethanol and obtained a total yield of 2.3 g. (46%), m.p. 208-211°. 

The checkers used 10% palladium-on-charcoal catalyst obtained from Baker and Company, Inc., 113 Astor Street, Newark, New Jersey. 

Reduction of 17a-EthynyI to 17a-Ethyl °° A solution of 5 g of 17a-ethynyl-androst-5-ene-3j9,17j5-diol in 170 ml of absolute alcohol is hydrogenated at atmospheric pressure and room temperature using 0.5 g of 5 % palladium-on-charcoal catalyst. Hydrogen absorption is complete in about 8 min with the absorption of 2 moles. After removal of the catalyst by filtration, the solvent is evaporated under reduced pressure and the residue is crystallized from ethyl acetate. Three crops of 17a-ethylandrost-5-ene-3) ,17j9-diol are obtained 3.05 g, mp 197-200° 1.59 g, mp 198.6-200.6° and 0.34 g, mp 196-199° (total yield 5.02 g, 90%). A sample prepared for analysis by recrystallization from ethyl acetate melts at 200.6-202.4° [aj, —70° (diox.). 

A solution of 61 parts 4-chloro-l,l-di-(4-fluorophenyl)-l-butene in 400 parts 2-propanol is hydrogenated at normal pressure and at room temperature in the presence of 5.5 parts palladium-on-charcoal catalyst 10% (exothermic reaction, temperature rises to about 30°C). After the calculated amount of hydrogen is taken up, hydrogenation is stopped. The catalyst is filered off and the filtrate is evaporated. The oily residue is distilled in vacuo, yielding l-chloro-4,4-di-(4-fluorophenyl)-butane, boiling point 166° to 168°C at 6 mm pressure ... 

The production of tetracycline by catalytic dechlorination is described in U.S. Patent 2,699,054 as follows Pure chlortetracycline (4.8 grams) was suspended in 100 ml of methanol and sufficient anhydrous dioxane was added to completely dissolve the product. To the solution was added 0.5 gram of 5% palladium-on-charcoal catalyst. The mixture was placed in a conventional hydrogenation apparatus and subjected to a pressure of 50 psi of hydrogen while being agitated. 

In preparation for the reduction of a nitro compound, the tetrahydroborate solution is added to an aqueous supension of palladium-on-charcoal catalyst. The reversed addition of dry catalyst to the tetrahydroborate solution may cause ignition of liberated hydrogen. 

Palladium on charcoal, catalyst for reductive methylation of ethyl p-nitrophenylacetate, 47, 69 in reduction of /-butyl azidoacetate to glycine f-butyl ester, 45, 47 Palladium oxide as catalyst for reduction of sodium 2-nitrobcnzcne-sulfinate, 47, S... 

Hydrogenolysis, of phenolic ethers to aromatics, 51, 85 of p-(1-phenyl-5-tetrazoly-loxy)biphenyl with palladium-on-charcoal catalyst to biphenyl, 51, 83... 

Palladium-on-charcoal catalyst, biphenyl from p-(1-pheny1-5-tetrazolyloxy)biphenyl and hydrogen, 51, 83... 

Hydrogenolysis of benzyloxycarbonyl dipeptide methyl esters in methanol over palladium or charcoal catalyst. - "... 

B. Glycine t-hutyl ester. In the center neck of a SOO-ml. suction filtration flask is placed a gas-inlet tube which is connected to a nitrogen cylinder, and on the side arm of the flask there is attached an exit tube leading to a suitable ventilation duct. The flask is placed on a magnetic stirrer, and a solution of 28.9 g. (0.18 mole) of /-butyl azidoacetate in 150 ml. of methanol and 0.7 g. of 5% palladium-on-charcoal catalyst is added to the flask. A stream of nitrogen is swept over the surface of the stirred suspension for 5 minutes, the nitrogen cylinder is replaced by a... 

The pentanitrates can be partially and fully denitrated by warming with pyridine and by hydrogenating with hydrogen over palladium-on-charcoal catalyst respectively. In the latter case the original pentitols were recovered. 

The silicic acid used for column chromatography and the Amberlite resin were Silicar CC-7 100-200 mesh purchased from Mallinckrodt Chemical Works, St. Louis, Mo. The 5% palladium on charcoal catalyst was purchased from Engelhard Industries Ltd., Newark, N. J. The tri-O-acetyl-D-glucal and the tri-O-acetyl-D-galactal (as a 70% solution in benzene) were purchased from Raylo Chemicals Limited, Edmonton, Alberta. 

Cycloaddition of methyl propiolate to 4-imino-4//-pyrido[ 1,2-a]py-rimidin-4-imine 481 in the presence of 5% palladium-on-charcoal catalyst as dehydrogenating agent yielded cyclazine derivative 482 in 12% yield (Scheme 27) (87YZ344). A similar reaction with dimethyl acetylenedicar-boxylate gave a mixture of addition (483), cycloaddition (484), and dehydrogenated (485) products in 16%, 23%, and 37% yields, respectively. 

A mixture of 3.6 g of (-)-(R)-N-[(3,4-dihydro-2H-l-benzopyran-2-yl)methyl]-N -(2-pyrimidinyl)-l,3-propanediamine dihydrochloride hemihydrate in 150 ml of methanol and 20 ml of 2-propanol saturated with HCI was hydrogenated in the presence of 1.5 g of palladium-on-charcoal catalyst (2%). After the calculated amount of hydrogen was taken up, the catalyst was filtered off and the filtrate was evaporated. The product was crystallized from acetonitrile, filtered off and dried, yielding 2.7 g (74.0%) of (-)-(R)-N-[(3,4-dihydro-2H-l-benzopyran-2-yl)methyl]-N -(l,4,5,6-tetrahydro-2-pyrimidinyl)-l,3-propanediamine dihydrochloride hemihydrate melting point 200.2°C. 

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