Borate trimethyl

Preparation. Sodium borohydride is manufactured from sodium hydride and trimethyl borate ia a mineral oil medium at about 275°C (26),... 

Hexafluoro-2,5-dihydrofuran [24849-02-3] is distilled into sulfur trioxide [7446-11-9] at 25°C. Addition of trimethyl borate [121-43-7] initiates a reaction which upon heating and distillation leads to a 53% yield of difluoromaleic anhydride. Dichloromaleic anhydride [1122-17-4] can be prepared with 92% selectivity by oxidation of hexachloro-1,3-butadiene with SO in the presence of iodine-containing molecules (65). Passing vaporized... 

Miscellaneous Uses. Research has demonstrated that fabrics could be treated with vaporous trimethyl borate (70% azeotrope) resulting in textiles (qv) that are smoulder resistant (48). 

Sodium borohydride is manufactured by Morton International, Inc. Treatment of trimethyl borate with a metal hydride, eg, NaH, ia the absence of a solvent yields sodium hydrotrimethoxyborate [16940-17-3] Na[HB(OCH2)3], (eq. 50) which disproportionates ia the presence of solvents such as tetrahydrofuran at 60—70°C (eq. 51) (112). 

Addition of diborane (eq. 52) under the latter conditions renders the production of MBH essentially continuous until consumption of the metal hydride is complete because trimethyl borate is regenerated. 

Trimethyl borate (113 ml) is added dropwise to 66 ml of deuterium oxide (exothermic reaction). The mixture is allowed to stand for 1/2 hr and the precipitated boric acid-d3 is removed by filtration. Sodium methoxide is... 

Methyl Borate (Trimethyl borate or Trimethoxy borine), (CH3.0)3B, mw 103.92, OB to C02 — 115.47, colorl liq, mp —29°, bp68°,d 0.92 g/cc at 20° vap d 3.59. Prepn other properties are given in Beil (Ref l). Sax (Ref 2) lists this compd as a dangerous fire hazard when exposed to heat or flame. It reacts with w or steam to produce toxic flammable vapors, and vigorously with oxid materials Refs 1) Beil 1, 287, (143) [275] 2) Sax... 

Trimethyl Borate, (CH3)3B03, did not gel any of the NC s Trimethyl Phosphate, (CH3)3P03, gelatinized all three. NC s rapidly and completely Dimethyl Sulfate. (CH3)2S04, gelatinized li and 12% N NC s rapidly and completely, the 13% N NC incompletely Dimethyl Sulfite, (CH3)2S03, gelatinized all three NC s rapidly and completely Butyl Nitrite,... 

S)-a, a-Diphenylpyrrolidinemethanol (127 mg) was placed in a 25 mL three-necked flask equipped with a magnetic stirrer bar, under nitrogen. A solution of trimethyl borate (62 mg) in dry tetrahydrofuran (5mL) was added. The mixture was stirred for 1 hour at room temperature. 

A similar approach was followed by Yamamoto and colleagues222. A chiral boron catalyst prepared from trimethyl borate and various (l ,l )-tartaric diamides 347 effectively catalyzed the cycloaddition of juglone to 1-triethylsilyloxy-1,3-butadiene (345) to give cycloadduct 346 with high enantioselectivity (equation 97). 

Commercial trimethyl borate contains an appreciable amount of methanol. It is removed by adding anhydrous lithium chloride to the bottle and allowing the mixture to stand with occasional shaking. The upper layer is decanted off and fractionated, b.p. 68-69°. The product must be protected from moisture. 

Trimethyl borate, reaction with Grignard reagents, 49, 91... 

A boron analog - sodium borohydride - was prepared by reaction of sodium hydride with trimethyl borate [84 or with sodium fluoroborate and hydrogen [55], and gives, on treatment with boron trifluoride or aluminum chloride, borane (diborane) [86. Borane is a strong Lewis acid and forms complexes with many Lewis bases. Some of them, such as complexes with dimethyl sulfide, trimethyl amine and others, are sufficiently stable to have been made commercially available. Some others should be handled with precautions. A spontaneous explosion of a molar solution of borane in tetrahydrofuran stored at less than 15° out of direct sunlight has been reported [87]. 

Several nonreductive methods for cleavage of benzyl groups have also been developed. Treatment with s-butyllithium, followed by reaction with trimethyl borate and then hydrogen peroxide, liberates the alcohol.24 The lithiated ether forms an alkyl boronate, which is oxidized as discussed in Section 4.9.2. 

Trimethoxyborane (trimethyl borate) was purchased from Wako Pure Chemical Industries, Ltd. and used as received. 

Trimethoxyborane ALDRICH Trimethyl borate Boric acid, trimethyl ester (8,9) (121-43-7)... 

Trimethyl borate was purchased from Tokyo Kasei Kogyo Co., Ltd. or Aldrich Chemical Company, Inc. and used without further purification. 

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