Hydrogen tetrafluoroborate

In a similar manner tetraphenylbismuth chloride [42967-53-3], C24H2QBiCl, (162) and tetraphenylbismuthonium tetrafluoroborate [36682-02-7], C24H2qBB1F4, (163) are obtained from pentaphenjlbismuth and hydrogen chloride or hydrogen tetrafluoroborate, respectively. When triphenylboron is used, the tetraphenylborate is obtained (162) ... 

In the aldohexopyranose series, treatment of methyl 2,3-anhydro-4,6-di-O-methyl-a-D-allopyranoside (34), or of the corresponding 4,6-diacetate (39), with hydrogen tetrafluoroborate in hydrogen fluoride at 70° afforded121 the corresponding derivatives of 2-deoxy-2-fluoro-D-al-tropyranosyl fluoride (35 and 40) and 3-deoxy-3-fluoro-D-glucopyrano-syl fluoride (36 and 41). Compounds 35 and 36 were hydrolyzed, and... 

Reaction of 4,6-diethoxy-l-ethylpyrimidinium tetrafluoroborate (21) showed similar behavior no N-deethylation, but deethoxylation at position 4 as well as at position 6 was observed, as indicated by the formation of the two isomeric products l,4-dihydro-6-ethoxy-l-ethyl-4-iminopyrimidine hydrogen tetrafluoroborate (23) and l,6-dihydro-4-ethoxy-l-ethyl-6-... 

Unless otherwise stated, all operations are carried out in flame-dried glassware under an inert gas atmosphere using standard Schlenk techniques.4 Solvents were dried over sodium (light petroleum, bp 40-60°C) or sodium-benzophenone (diethyl ether, THF). Lithium triethylhydroborate (1 — ) and hydrogen tetrafluoroborate (1 — ) diethyl ether complex were obtained from Aldrich and used as supplied. 

SYNS BORATE(l-),TETRAFLUORO-, HYDROGEN BOROFLUORIC ACID FLUOBORIC ACID (DOT) HYDROFLUOBORIC ACID HYDROGEN TETRAFLUOROBORATE TETRAFLUOROBORIC ACID... 

Although suspensions of rhodium(II) acetate, Rh2(C2H302)4, in 1-propanol are unaffected by mild carbonylation, protonation of such solutions by aqueous fluoroboric acid (hydrogen tetrafluoroborate) gives Rh2 + species which react with carbon monoxide at atmospheric pressure and 75° to give Rh6(CO)i6 in about 85 % yield. The synthesis provided here gives the details of this method. 

The reaction of pentaarylbismuth with 1 equiv. of bromine, hydrogen chloride, hydrogen tetrafluoroborate, triphenylsilanol and triphenylborane results in the cleavage of one of the Bi-C bonds to form tetraarylbismuth(V) compounds (Section 3.3.1). 

The process most widely used for introducing fluorine into an aromatic nucleus is thermal decomposition of diazonium fluoroborates (Schiemann reaction) lc,1242 1244 these salts are usually very stable, even towards deflagration. They are precipitated (i) on addition of hydrogen tetrafluoroborate or NaBF4 to a diazonium solution obtained as usual from the amine in hydrochloric acid or (ii) on diazotization of the amine in HBF4 solution by aqueous... 

Acid-catalysed addition of alcohols to olefins leads to ethers. It is catalysed by concentrated sulfuric acid,151 hydrochloric acid, acid salts, or aluminum chloride and hydrogen tetrafluoroborate and perchloric acid have also proved valuable,152,153 as has boron trifluoride.154 Addition of trisubstituted ethylenes such as isobutene and isopentene to alcohols is particularly easy it yields te/T-alkyl ethers.151 Disubstituted ethylenes react less easily, requiring higher temperatures and giving poorer yields. Cycloalkenes react only if there is a substituent attached to one of the doubly bonded atoms.155 Primary alcohols add more easily than do secondary ones, and tertiary alcohols rarely add at all. 

However, aliphatic alcohols can be alkylated by diazomethane if boron trifluoride etherate,788 hydrogen tetrafluoroborate,789 or aluminum chloride788 is added to the reaction mixture. Further, aliphatic alcohols can be methylated without further ado by diazomethane if hexane or heptane replaces ether as the solvent.790 Also the hydroxyl groups of hydroxy acids such as tartaric acid and their esters are smoothly methylated by diazomethane in ether 791, 792 and aliphatic alcohols can be methylated by diazomethane in the presence of sulfur dioxide or sublimed selenium dioxide, this reaction proceeding by way of the unstable alkyl methyl sulfite or selenite, respectively.793... 

Caution. Hydrogen tetrafluoroborate reacts with glass. Polyethylene equipment and a well-ventilated hood must be used. 

Initially, 1.67 mL of hydrogen tetrafluoroborate (48 wt % in HjO) [Aldrich] in 10 mL of distilled water is added dropwise (plastic syringe) with stirring (Teflon stir bar) to 22.78 mL of tetrabutylammonium hydroxide (40 wt % in H4O) [Aldrich] in a polyethylene beaker. A white precipitate, tetrabutylammonium tetrafluoroborate, forms immediately. The mixture is allowed to stir for 15 min and then cooled to 0° for 1 hr. The product is removed by Altering (polyethylene funnel and Alter flask) and is dried in a desiccator (plastic) over CaS04 for 12 hr. The Altrate is concentrated under vacuum to give additional product. The... 

Synonyms Borate (1-), tetrafluoro-, hydrogen Borofluoric acid Fluoroboric acid Hydrofluoboric acid Hydrofluoroboric acid Hydrogen tetrafluoroborate Tetrafluoroboric acid... 

Hydrogen tetrafluoroborate. See Fluoboric acid Hydroguard 1-15. See Isopropylhydroxylamine a-Hydro-uj-hydroxypoly (oxy-1,4-butanediyl) linear chain polymer. See Polytetrahydrofuran a-Hydro-u-hydroxypoly [oxy (methyl-1,2-ethanediyl)] a-Hydro-w-hydroxypoly (oxypropylene). See Polypropylene glycol Hydroiodic acid. See Hydriodic acid Hydroiodide-enterol. See lodochlorohydroxyquinoline Hydrokeratin 100M Hydrokeratin AL-30 Hydrokeratin AL-SD. See Hydrolyzed keratin Hydrokeratin HH-20SF. See Hair keratin amino acids... 

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