Catalyst sodium bicarbonate

Various synthetic protocols were available for the preparation of 1,2,4-triazoles and derivatives thereof Efhcient synthesis of 3,4,5-tri-substituted 1,2,4-triazoles 171 was accompHshed from the reaction of guanidines 169 with 2,2,2-tri-chloroethylimidates 170 in PEG-400 (14TL177). 3,5-Diaryl-l,2,4-triazoles 173 were synthesized from a domino nucleophilic substitution/ oxidative cycfr-zation sequence from 2 equivalents of amidines 172 with copper catalyst, sodium bicarbonate as base, 1,10-phenanthroline as an additive, and K3[Fe(CN)6]/air as the oxidant (14T1635). Sulfur-substituted 1,2,4-triazoles... 

To separate the oil added an equal volume of fresh cool water (note waited until solution cooled before adding the water). The oil started to drop out perfectly, used DCM to extract all traces of the oil. This woik up is by far the cleanest, easiest and simplest to date... (This dreamer was tried all method of ketone synthesis)... Once the oil was extracted, the extracts were pooled washed with sodium bicarbonate lx, saturated solution of NaCI 1x, and two washes with fresh dHzO... Some time was required for the work up as there was a little emulsion from the use of the base wash and then with the first water wash. The JOC ref suggested using an alumina column to remove the catalyst (could be a better way to go). 

When levuhnic acid (CH3CCH2CH2CO2H) was hydrogenated at high pressure over a nickel catalyst at 220°C a single product C5Hg02 was isolated in 94% yield This compound lacks hydroxyl absorption in its IR spectrum and does not immediately liberate carbon dioxide on being shaken with sodium bicarbonate What is a reasonable structure for the compound" ... 

Cl Reactive Blue 19 (9) is prepared by the reaction of bromamine acid (8) with y -aminophenyl-P-hydroxyethylsulfone [5246-57-1] (76) ia water ia the presence of an acid-hinding agent such as sodium bicarbonate and a copper catalyst (Ullmann condensation reaction) and subsequent esterification to form the sulfuric ester. 

A-Homo-cholest-4a-en-3-one (16a) A total of 200 ml of a cold 0.232 M solution of diazomethane in methylene dichloride is added dropwise to a stirred solution of cholestenone (15a 5.6 g) in anhydrous methylene dichloride (25 ml) containing freshly prepared fiuoroboric acid catalyst. Nitrogen evolution begins immediately, and after 5 min the colorless solution turns cloudy due to precipitated polymethylene. After the addition is complete, the mixture is stirred for 1 hr and filtered. The filtrate is diluted with ether, washed with saturated sodium bicarbonate solution followed by... 

In addition to modification of the catalyst, several variants of the Biginelli reaction have emerged as viable alternatives however, each method requires pre-formation of intermediates that are normally formed in the one-pot Biginelli reaction. First, Atwal and coworkers reported the reaction between aldol adducts 39 with urea 40a or thiourea 40b in the presence of sodium bicarbonate in dimethylformamide at 70°C to give 1,4-dihydropyrimidines 41. DHPM 42 was then produced by deprotection of 41. 

This Crude product (15.8 g) In water (360 ml) was added to a prehydrogenated suspension of 10% palladium on charcoal (4 g) in water (400 ml), and hydrogenation was continued for 30 minutes. The catalyst was removed and the filtrate was adjusted to pH 7.5 with sodium bicarbonate, then evaporated at low temperature and pressure. The residue was purified by chromatography on a column of cellulose powder, eluting first with butanol/ ethanol/water mixture and then with acetone/isopropanol/water. The main fraction was evaporated at low temperature and pressure to give a 32% yield of the sodium salt of a-carboxybenzylpenicillin as a white powder. The product was estimated by manometric assay with penicillinase to be 58% pure. 

Unsymmetrical as well as symmetrical anhydrides are often prepared by the treatment of an acyl halide with a carboxylic acid salt. The compound C0CI2 has been used as a catalyst. If a metallic salt is used, Na , K , or Ag are the most common cations, but more often pyridine or another tertiary amine is added to the free acid and the salt thus formed is treated with the acyl halide. Mixed formic anhydrides are prepared from sodium formate and an aryl halide, by use of a solid-phase copolymer of pyridine-l-oxide. Symmetrical anhydrides can be prepared by reaction of the acyl halide with aqueous NaOH or NaHCOa under phase-transfer conditions, or with sodium bicarbonate with ultrasound. 

The addition of dry HCl to a mixture of a nitrile and an alcohol in the absence of water leads to the hydrochloride salt of an imino ester (imino esters are also called imidates and imino ethers). This reaction is called the Pinner synthesisThe salt can be converted to the free imino ester by treatment with a weak base such as sodium bicarbonate, or it can be hydrolyzed with water and an acid catalyst to the corresponding carboxylic ester. If the latter is desired, water may be present from the beginning, in which case aqueous HCl can be used and the need for gaseous HCl is eliminated. Imino esters can also be prepared from nitriles with basic catalysts. ... 

The atom economy for this process is 86.5% (100 X 116/134), which is reasonable. To calculate the E-factor and EMY further information is needed. From published literature (Vogel s Practical Organic Chemistry ), a standard procedure is to mix butanol (37 g) with glacial acetic acid (60 g), and a small amount of sulfuric acid catalyst (ignored in all calculations). Following completion of the reaction the mixture is added to water (250 g). The crude ester is washed further with water (100 g), then saturated sodium bicarbonate solution (25 g) and finally water (25 g). After drying over 5 g of anhydrous sodium sulfate the crude ester is distilled to give product (40 g) in a yield of 69%. 

Several modified reaction conditions have been developed. One involves addition of silver salts, which activate the halide toward displacement.134 Use of sodium bicarbonate or sodium carbonate in the presence of a phase transfer catalyst permits Reactions involving especially mild conditions to be used for many systems.135 Tetraalkylammonium salts... 

The most widely used of the methods involving a reduction of periodate, only, to iodate employs the arsenite ion4 as reductant, in a solution maintained at neutrality with sodium bicarbonate, with iodide ion as catalyst. 

Carbenicillin Carbenicillin, [25 -(2a,5a,6j3)]-3,3-dimethyl-7-oxo-6-(2-carboxy-2-phenylacetamido)-4-thia-l-azabicyclo[3.2.0]-heptan-2-carboxylic acid (32.1.1.32), is synthesized by direct acylation of 6-APA in the presence of sodium bicarbonate by phenylmalonic acid monobenzyl ester chloride, which forms the benzyl ester of carbenicillin (32.1.1.31), the hydrogenolysis of which using palladium on carbon or calcium carbonate as catalyst gives the desired product (32.1.1.32) [51-58]. 

A number of modified reaction conditions have been developed. One involves addition of silver salts, which activate the halide toward displacement.94 Use of sodium bicarbonate or sodium carbonate in the presence of a phase-transfer catalyst permits especially mild conditions to be used for many systems.95 Tetraalkylammonium salts often accelerate reaction.96 Solid-phase catalysts in which the palladium is complexed by polymer-bound phosphine groups have also been developed.97 Aryl chlorides are not very reactive under normal Heck reaction conditions, but reaction can be achieved by inclusion of triphenylphosphonium salts with Pd(OAc)2 or PdCl2 as the catalyst.98... 

To a solution of 0.200 g. (0.515 mmole) of dry dihydrocholesterol (Note 1) in 10 ml. of methylene chloride contained in a 50-ml. Erlenmeyer flask is added 0.3 ml. of a catalyst stock solution containing 0.0016 ml. (0.018 mmole) of concentrated fluoboric add (Note 2) in 3 1 anhydrous diethyl ether-methylene chloride (Note 3). The solution is swirled, and a 0.451/ solution of diazo-methaue (Note 4) in dry methylene chloride is added from a buret (Note 5) at a rate of about 2 ml. per minute. The yellow color of diazomethane disappears rapidly on contact with the reaction mixture and nitrogen is vigorously evolved. When about 3 ml. of diazomethane solution has been added, the reaction becomes sluggish. The yellow color persists for several minutes after the total amount of 3.9 ml. of diazomethane solution (1.76 mmoles) has been added (Note 6). After 1 hour the reaction mixture is filtered to remove a small amount of amorphous polymethylene, which is washed with methylene chloride. The washings are combined with the methylene chloride solution, washed with 5 ml. of saturated aqueous sodium bicarbonate, with three... 

The allylic alcohol substitution reaction may also be carried out in DMF solution with sodium bicarbonate as the base at 100 to 125° with palladium-phosphine catalysts, in which case only carbonyl products are formed. With this catalyst combination nonallylic, unsaturated alcohols also react to form carbonyl compounds in good yields. For example, in an extreme case, 9-decen-l-ol and bromobenzene gave some 10-phenyldecanal (40) ... 

The effect of the nature of the electrophile on the stereoselectivity of reactions with substrates containing a terminal alkene and an allylic substituent is dramatically illustrated by some recent results with palladium electrophiles.124 Cyclizations of 3-methyl- or 3-phenyl-5-hydroxyalkenes with palladium catalysts proceed with high selectivity (>9 1) for the 2,3-trans isomer (equation 41).50-124 It is suggested that the steric interactions of the palladium-alkene complex affects the stereochemistry of these cyclizations. In some related cyclizations to form tetrahydropyran products (equation 42 and Table 10), reaction with iodine in the presence of sodium bicarbonate gives a different major diastereomer from cyclization with mercury(II) trifluoroacetate or palladium chloride.123... 

Oxidation of 2,3-dihydrobenzodiazepines by various oxidants (H202, Se02, peracids, etc.) normally gives resinous reaction products which cannot be easily identified. However, described in [107] is the oxidation of 7V-bezoyl derivatives of benzodiazepines 97 by meta-chloroperbenzoic acid in the presence of sodium bicarbonate and triethylbenzyl ammonium chloride (used as an interphase catalyst) which yields compounds 98 (Scheme 4.32). 

Stalder, C. J., Chao, S., Summers, D. P., and Wrighton, M. S. (1983). Supported Palladium Catalysts for the Reduction of Sodium Bicarbonate to Sodium Formate in Aqueous Solution at Room Temperature and One Atmosphere of Hydrogen. Journal of the American Chemical Society, 105, 6318-6320. 

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