Charcoal residual atmosphere

The burial of pyrogenic charcoal residues that are not subject to microbial oxidation even over geological time scales, and that thus constimte a significant sink for atmospheric CO2 and consequently a source for O2 [10]. Because the risk of fires increases with the growing atmospheric O2 content [82], on geological time scales this may establish a positive feedback loop, which favors O2 buildup in the atmosphere. 

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.). 

Although this chemistry is complex, the basic process is reduction of iron oxide by carbon in an atmosphere depleted of oxygen. Archaeologists have found ancient smelters in Africa (in what is now Tanzania) that exploited this chemistry to produce iron in prehistoric times. Early African peoples lined a hole with a fuel of termite residues and added iron ore. Chamed reeds and charcoal provided the reducing substance. Finally, a chimney of mud was added. When this furnace was fired, a pool of iron collected in the bottom. 

Krypton is the 81st most abundant element on Earth and ranks seventh in abundance of the gases that make up Earths atmosphere. It ranks just above methane (CH ) in abundance in the atmosphere. Krypton is expensive to produce and thus has hmited use. The gas is captured commercially by fractional distillation of liquid air. Krypton shows up as an impurity in the residue. Along with some other gases, it is removed by filtering through activated charcoal and titanium. 

B. 1,3-Dimethyl-6H-benzo[b]naphtho[1,2-d]pyran-6-one (4). Under an argon atmosphere, a 250-mL, oven-dried, round-bottomed flask, equipped with a reflux condenser, is charged with freshly distilled N,N-dimethylacetamide (DMA, 130 mL), 3,5-dimethylphenyl 1-bromo-2-naphthoate (3, 3.24 g, 9.12 mmol), palladium(ll) acetate (205 mg, 0.913 mmol), triphenylphosphine (481 mg, 1.83 mmol), and sodium acetate (1.50 g, 18.3 mmol) (Notes 4 and 5). The orange suspension is degassed three times, placed in a preheated (130°C) oil bath (Note 5), and stirred at 130°C for 12 hr (Note 6). Removal of the solvent at 40°C (0.1 mbar, 0.075 mm) gives a black oily residue, which is Chromatographed (5 x 40 cm column, silica gel 0.063 - 0.2 mm, 170 g, 1 cm of charcoal at the top of the column eluent hexane / diethyl ether 5 1), to yield 2.00 g (80%) of the lactone 4 as a slightly yellow solid. Recrystallization from diethyl ether / hexane delivers 1.63 g (65%) of colorless or pale yellow crystals (Note 7). 

A20-mM solution of pentasaccharide 15 (R=NaSOj), in 2.5 1 methanol/water, was shaken far 60 h at room temperature in an hydrogen atmosphere (1 bar) in the presence of 10% palladium an charcoal (150 mg). The mixture was filtered over a Celite bed, the solution was evaporated, and the residue was dissolved in water. This aqueous sedation was passed through a column of cation-exchange resin AG50 WX8 (Na+). Pentasaccharide 16 was eluted with water and recovered by freeze-drying [a, —7° (c 1.54 in water, after a 24-h standing) H NMR (DjO) 8 4.324 (1H, dd, 9.87, 3.25 Hz, H-3e). 

V-(9-Fluorenylmethoxycarbonyl)-0-(2,3,4-tri-0-benzoyl- 3-D-xylopyranosyl)-L-serine 15. The Fmoc O-xylosyl serine benzyl ester 13 (1.0 g, 1.2 mmol) is stirred in methanol (40 mL) at room temperature and subjected to hydrogenolysis for 18 h under atmospheric pressure using palladium-charcoal (0.2 g, 5%) as the catalyst. The educt 13 dissolves slowly. The catalyst is filtered off, and the solvent evaporated in vacuo. If the residue is not pure according to thin-layer chromatography (TLC), it is dissolved in 2 mL of ethyl acetate and purified by chromatography on a short column of silia gel 60. The byproducts are eluted with petroleum ether-ethyl acetate the product 15 with methanol yield 0.85 (92%) mp 109°C, [cr]D -12.6° (c 0.3, CH3OH) Rf 0.64 (toluene-ethanol, 1 2). 

A solution of 2.21 g 3,5-dimethoxy-4-ethoxyphenylacetonitrile in 25 mL EtOH containing 2.5 mL concentrated HC1 and 400 mg 10% palladium on charcoal, was shaken in a 50 lb/sq.in. atmosphere of hydrogen for 24 h. Celite was added to the reaction suspension and, following filtration, the solvents were removed under vacuum. The residue was recrystallized from IPA/Et20 to yield 2.14 g 3,5-dimethoxy-4-ethoxyphenethylamine hydrochloride (E) with a mp of 166-167 °C. 

A solution of 1.7 g of 2-hydroxymethyl-3-benzyloxy-(l-hydroxy-2-tert-butyl-aminoethyl)pyridine in 30 ml of methanol containing 1.2 ml of water is shaken with 700 mg of 5% palladiumon-charcoal in an atmosphere of hydrogen at atmospheric pressure. In 17 minutes the theoretical amount of hydrogen has been consumed and the catalyst is filtered. Concentration of the filtrate under reduced pressure provides 1.4 g of the crude product as an oil. Ethanol (5 ml) is added to the residual oil followed by 6 ml of 1.75 N ethanolic hydrogen chloride solution and, finally, by 5 ml of isopropyl ether. The precipitated product is filtered and washed with isopropyl ether containing 20% ethanol, 1.35 g, melting point 182°C (dec.). 

A solution of 3-(4-chloro-5-fluoropyrimidin-6-yl)-2-(2,4-difluorophenyl)-l-(lH-l,2,4-triazol-l-yl)butan-2-ol, enantiomeric pair B (0.307 g, 0.8 mmol) in ethanol (20 ml) was hydrogenated at atmospheric pressure and at room temperature in the presence of 10% palladium-on-charcoal (30 mg) and sodium acetate (0.082 g, 1 mmol). After 5 hours a further 10 mg of 10% palladium-on-charcoal was added and hydrogenation was continued for an additional 1 hour. The catalyst was removed by filtration and the filtrate was concentrated in vacuo. Flash chromatography of the residue on silica using 97 3 ethyl acetate/methanol as the eluent provided, after combination and evaporation of appropriate fractions and trituration with diethyl ether, the 2-(2,4-difluorophenyI)-3-(5-fluoropyrimidin-4-yl)-l-(lH-l,2,4-triazol-I-yl)butan-2-ol enantiomeric pair B, (0.249 g, 89%), m.p. 127°C. 

A solution of the above compound in a mixture of ethanol (20 ml) and acetic acid (20 ml) is shaken with a 30% palladium-on-charcoal catalyst (0.1 g) in an atmosphere of hydrogen at laboratory temperature and pressure until 250 ml of hydrogen is absorbed. The mixture is filtered, the filtrate is evaporated to dryness under reduced pressure and to the residue is added a hot solution of fumaric acid (1.25 g) in ethanol (15 ml). The mixture is kept at 5°C for 12 hours and is then filtered, and the solid residue is washed with hot ethanol and then dried. There is thus obtained l-p-hydroxyphenoxy-3-beta-(morpholinocarbonamido)ethyl-amino-2-propanol hydrogen fumarate, m.p. 168-169°C (with decomposition). 

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