Benzyltrimethylammonium hydroxide Triton

Benzyltrimethylammonium hydroxide (Triton B) [100-85-6] M 167.3, d 0.91. A 38% soln (as supplied) was decolorized (charcoal), then evaporated under reduced pressure to a syrup, with final drying at 75° and 1 mm pressure. Prepared anhydrous by prolonged drying over P2O5 in a vacuum desiccator. 

A solution of benzyltrimethylammonium hydroxide (Triton B, 10ml, 40% in MeOH) was treated with aqueous HF (ca. 8.6ml, 4.7%) until the pH reached 8-7. The solvent was removed in vacuo (ca. 1 mm), and the residue was dried at 50°C/0.5 mmHgfor 20 h. The resulting highly hygroscopic solid was powdered, and then stored in a desiccator over P205. 

Quaternary ammonium hydroxides are strong bases comparable to NaOH and KOH. Recently one of them, benzyltrimethylammonium hydroxide (Triton B), has proved to be a very efficient dehydrohalogenation agent. Thus a 40% methanolic solution of Triton B in benzene affords higher yields of acetylenes than acloholic KOH or NaNHi (e.g. equations 66 and 67) . In a continuation of this work it has been found that the method is not only applicable to acetylenic hydrocarbons, but... 

Measure into a 25 x 150-mm testtube 2.1 gofbenzil,2.1 gof 1,3-diphenyl-acetone, and 10 mL of triethylene glycol, using the solvent to wash the walls of the test tube. Support the test tube in a hot sand bath, stir the mixture with a thermometer, and heat until the benzil is dissolved, then remove it from the sand. Measure 1 mL of a commercially available 40% solution of benzyltrimethylammonium hydroxide (Triton B) in methanol into a 10 X 75-mm test tube, adjust the temperature of the solution to exactly 100°C, remove from heat, add the catalyst, and stir once to mix. Crystallization usually starts in 10-20 s. Let the temperature drop to about 80°C and then cool under the tap, add 10 mL of methanol, stir to a thin crystal slurry, collect the product, and wash it with methanol until the filtrate is purple-pink, not brown. The yield of deep purple crystals is 3.3-3.7 g. If either the crystals are not well formed or the melting point is low, place 1 g of material and 10 mL of triethylene glycol in a vertically supported test tube, stir with a thermometer, raise the temperature to 220°C to bring the solid into solution, and let stand for crystallization (if initially pure material is recrystallized, the recovery is about 90%). 

N-t-Butyloxycarbonylandno acids.1 Amino acids, in the form of their salts with benzyltrimethylammonium hydroxide (Triton B), react with (1) in DMSO or DMF within a few hours to give BOC-amino acids in 80-90% yield. 

Also ethyl 4-nitro-3-phenylbutyrate is obtained in 76% yield from nitro-methane and ethyl cinnamate when benzyltrimethylammonium hydroxide (Triton B) is used as catalyst.81... 

TMG (1), as well as benzyltrimethylammonium hydroxide (Triton B) in pyridine and sodium ethoxide in ethanol, was found to work as base catalyst in the cyclopropanation of steroid skeletons controlled by intramolecular Sn2 reaction [70]. Thus, 6-oxo-3a,5-cyclo-5ot-steroids were given in high yields for the reaction of 3p-tosyloxy (or -chloro)-6-oxo derivatives (Table 4.8). 

In 1995, Ando reported that a,p-unsaturated esters could be obtained with high Z selectivity from the HWE reaction of aldehydes with diphenylphosphonoacetates in the presence of benzyltrimethylammonium hydroxide (Triton B) or NaH in tetra-hydrofuran [182], Later, Ando [183-186], Motoyoshiya [187, 188], and Touchard [189, 190] further defined this protocol by modifying diphenylphosphonoacetates and found that the employment of bis(o-alkylphenyl)phosphonoacetates led to higher Z selectivity (Scheme 39). The combination of NaH and Nal has been identified as an effective base/additive system to improve the Z selectivity [191]. Moreover, the Ando modification has recently been applied to the ring closure of various macrolides with high Z selectivity, which is complementary to that of traditional intramolecular HWE reaction (Scheme 40) [192, 193]. 

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