Boron trifluoride etherate reagent

The structures of partially benzoylated derivatives of 1,6-anhydro-4, 6 -0-benzylidene-/3-maltose were established by methylation studies.51 During the course of this investigation, 2,3- and 3,3 -di- and 2,3,3 -tri-methyl ethers of l,6-anhydro-4, 6 -0-benzylidene-/3-maltose were prepared by using diazomethane-boron trifluoride etherate reagent. Methyl [methyl 2,3-di-0-methyl-4-0-(2,3,4,6-tetra-0-methyl-a -D-glucopyranosyl)-/3-D-glucopyranosid]uronate (15) has been synthe-... 

Covalent fluondes of group 3 and group 5 elements (boron, tin, phosphorus, antimony, etc ) are widely used m organic synthesis as strong Lewis acids Boron trifluoride etherate is one of the most common reagents used to catalyze many organic reactions. A representative example is its recent application as a catalyst in the cycloadditions of 2-aza-l,3-dienes with different dienophiles [14] Boron trifluoride etherate and other fluonnated Lewis acids are effective activators of the... 

Synthesis of Derivatizing Reagent III. We placed 50 mL of methanol, which had been previously dried over 4-S molecular sieves, in a 100-mL round-bottom flask and added 6.0 g of 2-hydroxynicotinic acid and 3 mL of boron trifluoride etherate. The solution was heated to reflux for 24 h and the solvent was removed under reduced pressure. The residue was dissolved in 50 mL of 0.1-ff sodium hydroxide and extracted with 60 mL of chloroform. The chloroform extract was concentrated under reduced pressure and the residue crystallized from isopropyl alcohol. The yield of 3-carbomethoxy-2(lH)pyridone was 5.0 g mp 152.5-154°C NMR (CDCI3) 6 3.85 (s, 3, -CH3), 6.34 (t, 1,... 

Note It is reported that the use of chlorobenzene as solvent is essential when the reagent is to be used to detect aromatic amines [1]. In the case of steroids, penicillins, diuretics and alkaloids the reaction should be accelerated and intensified by spraying afterwards with dimethylsulfoxide (DMSO) or dimethylformamide (DMF), indeed this step makes it possible to detect some substances when this would not otherwise be possible [5,9-11] this latter treatment can, like heating, cause color changes [5,9]. Penicillins and diuretics only exhibit weak reactions if not treated afterwards with DMF [10, 11]. Steroids alone also yield colored derivatives with DMSO [9]. Tlreatment afterwards with diluted sulfuric acid (c = 2 mol/L) also leads to an improvement in detection sensitivity in the case of a range of alkaloids. In the case of pyrrolizidine alkaloids it is possible to use o-chloranil as an alternative detection reagent however, in this case it is recommended that the plate be treated afterwards with a solution of 2 g 4-(dimethyl-amino)-benzaldehyde and 2 ml boron trifluoride etherate in 100 ml anhydrous ethanol because otherwise the colors initially produced with o-chloranil rapidly fade [12]. 

Boron trifluoride etherate was purchased from Nacalai Tesque or Aldrich Chemical Company, Inc. and used without further purification. Since the purity of the BF3 complex affects the yield of the quinone, reagent stored for a long period should be distilled prior to its use. 

Early attempts to convert aliphatic nitriles into primary cyclopropylamines, in the same way as N,N-dialkylcarboxamides 44 are transformed to N,N-dialkylcyclopropylamines 47 under the action of Grignard reagents and Ti(OiPr)4, were unfruitful [136], However, Szymoniak et al. have found that the addition of a Lewis acid such as boron trifluoride etherate is necessary to activate azatitanacyclopentene 153 resulting from insertion of... 

Reagent grade tetrahydrofuran (Fisher Scientific Company) was either freshly distilled from sodium metal and benzophenone or dried for at least 24 hr over activated Linde 4 A molecular sieves. Boron trifluoride etherate was redistilled prior to use. Fresh bottles of redistilled boron trifluoride etherate purchased from Aldrich Chemical Company, Inc., also usually give good results. 

Aminosulfides, important building blocks for the synthesis of various bioactive molecules, can be prepared by the thiolysis of aziridines in the presence of Bi(OTf)3 (5 mol%) [36]. Even though Lewis acids such as boron trifluoride etherate and zinc chloride, as well as Bronsted acids such as trifluoromethanesulfonic acid, have been employed as acid catalysts, these methods suffer from disadvantages like the use of stoichiometric amount of catalysts [37—40], harsh conditions, the use of large excess of thiols and necessitate anhydrous conditions to produce the desired products. Furthermore, these reagents cannot be recovered and recycled because they decompose or deactivate under quenching conditions. 

Methyl Ethers. Methylation of sucrose is generally conducted under basic conditions. Etherification occurs initially at the most acidic hydroxyl groups, HO-2, HO-T, and HO-3f, followed by the least hindered groups, HO-6 and HO-6. Several reagents have found use in the methylation of sucrose, including dimethyl sulfate—sodium hydroxide (18,19), methyl iodide—silver oxide—acetone, methyl iodide—sodium hydride in N, N- dimethyl form amide (DMF), and diazomethane—boron trifluoride etherate (20). The last reagent is particularly useful for compounds where mild conditions are necessary to prevent acyl migration (20). 

These reagents are also useful for the preparation of 1,2-diols. Upon exposure to Lewis acids such as boron trifluoride etherate (BFa-OEta), the a-alkoxy and oc-siloxyallyl stannanes undergo a stereospecific, intermolecular 1,3-isomerization to give y-alkoxy- and y-siloxy allylic stannanes.3. .7 When tert-butyldimethylsilyl trifluoromethanesulfonate is substituted for chloromethyl methyl ether in the above procedure, the isomeric -y-siloxy allylic stannane can be obtained directly with no loss of enantioselectivity.6 These stannanes can then be added to various aldehydes to give monoprotected 1,2-diols with high diastereoselectivity.8... 

Synthesis of racemic naproxene Friedel-Crafts acylation (aluminum chloride - nitrobenzene) of p-naphthol methyl ether affords 2-acetyl-6-methoxy naphthalene, which, when treated with either dimethyl sulfonium or dimethylsulfoxonium methylide, gives 2-(6-methoxynaphthalen-2-yl)propylene oxide. Treatment of the latter with boron trifluoride etherate in tetrahydrofuran gives 2-(6-methoxynaphthalen-2-yl)propionaldehyde, which is oxidized using Jones reagent (4 M chromic acid) to yield the racemic 2-(6-methoxynaphthalen-2-yl)propionic acid. 

Allyltributyltin, 10 Boron trifluoride etherate, 43 Di-jjL-carbonylhexacarbonyldicobalt, 99 Grignard reagents, 138 Ketenylidenetriphenvlphosphorane, 154 Methoxyamine, 177 Reformatsky reagent, 346 Tin(IV) chloride, 300 Tributylcrotyltin, 10 Aldol reactions General considerations, 202 Directed aldols using imines Norephedrine, 200... 

Organoaluminum reagents, 202 Sodium iodide-Boron trifluoride ether-ate, 282... 

Organocopper reagents-Boron trifluoride etherate, 208 9-(Phenylseleno)-9-borabicyclo-[3.3. ljnonane, 245 B-3-Pinanyl-9-borabicyclo-[3.3.ljnonane, 249 Potassium triethylborohydride, 260... 

Lithium dialkylcuprates-Boron trifluoride etherate, 208 Lithium diallylcuprate, 11 Lithium dibutylcuprate, 61, 208, 344 Lithium dibutylcuprate-Boron trifluoride etherate, 208 Lithium dimethylcuprate, 63, 151, 258 Lithium dimethylcuprate-Boron trifluoride etherate, 208 Organocopper reagents, 11, 61, 63, 131, 151, 207, 344 Organocopper reagents-Boron trifluoride etherate, 208 Organolithium reagents-Copper(I) halides, 58... 

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