Tetrabutylammonium hydroxide, synthesis

The original conditions used amines as solvents or cosolvents. Several other bases can replace the amine. Tetrabutylammonium hydroxide or fluoride can be used in THF (see Entry 1 in Scheme 8.11).163 Tetrabutylammonium acetate is also effective with aryl iodides and EWG-substituted aryl bromides (Entry 2).164 Use of alkenyl halides in this reaction has proven to be an effective method for the synthesis of enynes165 (see also Entries 5 and 6 in Scheme 8.11). 

Similar procedures adopted for the synthesis of TS-1 (the mixed alkoxide method, dissolved titanium method, pre-hydrolysis method, wetness impregnation method, and promoter induced synthesis method) were also used for the synthesis of TS-2. Tetrabutylammonium hydroxide (TBAOH) instead of TPAOH was used as the template (6,7,305-308). 

Although true for many oximes of aliphatic and alicyclic ketones, the previous sequence is not absolute and can change depending on the reaction conditions and ketoxime type. Tetrabutylammonium hydroxide, for instance, which catalyzes fairly actively in the synthesis of 4,5,6,7-tetrahydroindole from cyclohexanon oxime and acetylene (79KGS197), turned out to be nearly inert with alkyl aryl ketoximes (78ZOR1733). 

The />-pentazolylphenolate anion could not be prepared by direct synthesis from />-diazobenzoquinone and was obtained by the reaction of /<-hydroxyphenylpentazole with tetrabutylammonium hydroxide (Equation 4) <2002JOC1354>. Both />-hydroxyphenylpentazole and the/>-pentazolylphenolate anion are more stable in mixtures of CD2CI2 and CD3CN than in mixtures containing CD3OD <2002AGE3051>. Substituents in meta- and ortho-position favor the decomposition of the pentazoles. No ortho- or K 7-substituted arylpentazoles were isolated so far. 

Titanium Silicalite-2 (TS-2), structurally similar to TS-1, could be prepared likewise using tetrabutylammonium hydroxide as the template [13, 14]. Titanium aluminum Beta (Ti,Al-[3) was prepared by hydrothermal synthesis from amorphous silica, sodium aluminate, tetraethyltitanate and tetraethylammonium hydroxide [15]. The presence of A1 was necessary for the crystallization of the product. Al-free Titanium Beta (Ti-[3) could be obtained in the presence of particular templates, such as dibenzyldimethylammonium hydroxide [16]. Titanium Mordenite (Ti-MOR), conversely, was obtained by post-synthesis insertion of Ti to dealuminated Mordenite [17]. Ti-MWW (Ti-MCM-22) was obtained by the synthesis of the lamellar precursor of Ti,B-MCM-22 followed by acid treatment to remove most of the boron and extra-framework Ti and finally calcination to burn out the template and bring about the condensation of lamellae into the three-dimensional MWW structure [18]. Ti is present in a number of different environ-... 

C-A -Methylketanserin 279, the analogue of serotonin-2 receptor antagonist, ke-tanserin 280, has been synthesized for studying these receptors in vivo using PET by alkylation of ketanserin in DMF solution in the presence of small amount of aqueous tetrabutylammonium hydroxide at 80 °C for 2 minutes followed by chromatographic purification during 22 minutes total synthesis time from EOB, with 10% radiochemical yield calculated at the end of synthesis (EOS). 

The Carbon Black Pearls labeled BP 2000 was supplied by Cabot Corp. 10 g of carbon black pearls (BP-2000) was dried in an oven at 110 °C overnight. In a 200-mL flask, 17.2 g of 40 % tetrabutylammonium hydroxide, 2.5 g of I BO and 15.1 g of ethanol was stirred to obtain a homogeneous solution. The dried carbon black was impregnated with this solution to incipient wetness. After evaporation of ethanol at room temperature for 12 h, carbon particles were impregnated with 19.3 g of tetraethyl orthosilicate. This mixture was left at ambient conditions to hydrolyze overnight. The hydrothermal synthesis was performed in a Teflon-lined autoclave at 180 °C for 72 h. Then the autoclave was cooled, a solid product was filtered and washed with distilled water. Calcination was carried out in a muffle oven at 550 °C for 18 h [86],... 

The hydrothermal synthesis of Zr-Sil-2 samples was carried out using the gel solutions containing tetraethylorthosilicate (TEOS), tetrabutylammonium hydroxide (TBAOH, 40% aqueous), ZrCU, Zr(acac)4 and distilled water. The molar composition of the final gel was the following Si02 x Zr02 0.40 TBAOH 30 H2O with 0[Pg.219]

Carbon-11 can also be inserted into an aromatic ring Methyl chloroformate has been converted into carbon-11 labelled oxalic acid in a three-step synthesis. The first step (equation 75) was done in a water-dichloromethane mixture using tetrabutylammonium hydroxide and CN" under phase transfer catalysis conditions. The conversion to the diethyl ester and to the oxalic acid were done in high yields in 0.5 and 0.25 minute, respectively, in a microwave cavity. 

Step [86,87,233,234]. Peiro and coworkers [235] recently reported on the synthesis of Ti02 anatase phase with a nanorod morphology (9 x 5mn size) using controlled hydrolysis of tetraisopropyl orthotitanate (TIP) and tetrabutylammonium hydroxide ((TBA)OH) as a steric stabilizing agent. 

When the synthesis was modified by adding ethylenediamine en)y diethylenetriamine dien) or triethylenetetramine trien) to the aqueous solution of tetrabutylammonium hydroxide and... 

Jain and co-workers reported a concise total synthesis of cefuroxin (Ceftin) from readily accessible 7-amino-3-acetoxymethyl-3-cephem-4-carboxylic acid. Hydrolysis of 7-amino-3-acetoxymethyl-3-cephem-4-carboxylic acid in aqueous methanol followed by acidification with tetrabutylammonium hydroxide provided the corresponding alcohol in 88% yield. Condensation of this compound with the ammonium salt of 2-furanyl-(Z)-2-methoxyiminoacetyl chloride provided the core structure in 77% yield. Protection of the free alcohol as a carbamate with chlorosulfonyl isocyanate, followed by conversion to the sodium salt, gave the desired compound in 83% yield (56% overall yield). 

In continuation of the use of dichloromethyllithium in the synthesis of branched-chain sugars (see also Vol. 29, p. 192, ref. 8 and Vol. 25, p. 162, ref. 9) 3-C-(dichloromethyl)-1,2 5,6-di-0-isopropylidene-a-D-allofuranose reacted with tetrabutylammonium hydroxide in DMSO to produce 5, but with caesium acetate-18-crown-6 in toluene to produce the inversion product 6. The former was thought to arise by conventional hydrolysis and the latter by formation of a j piro-chloroepoxide intermediate followed by nucleophilic ring opening at the quaternary centre. Other C-CHCI2 secondary compounds behaved similarly. ... 

Anhydro-B-D-glucopyranose has been identified as a product from hydrothermolysis of cellulose and its degradation in aqueous solution at 200-240°C examined.A mild procedure for the synthesis of 1,6-anhydrohexopyranoses involves treatment of the pentabromophenyl g-glycosides (obtained in two steps from the B-peracetates) with tetrabutylammonium hydroxide at 20°C, followed by... 

Gold nanoparticles (2.5-7.5 nm diameter) were obtained by Martino and others [402] by reduction of AUCI4 via lithium borohydride in tetrahydrofuran in the reverse micelle system DDAB (didodecyldimethylammonium bromide)/toluene. A purple-colored gold colloid was observable. The particles were encapsulated by silica gels formed in the micellar system by hydrolysis-condensation of TEOS or a prehydrolyzed TEOS, already added in the system. Gelation of silica was achieved by the addition of tetrabutylammonium hydroxide (quicker in case of pre-hydrolyzed TEOS). The particle size was found to be independent of reaction stoichiometry, gel precursor type (TEOS/pre-hydrolyzed TEOS) and the washing step after synthesis. 

The synthesis of NH- and N-vinyl-4,5,6,7-tetrahydroindoles is implanented successfully at cyclohexanone oxime-acetylene molar ratio of l (2-5) at 90 C-140 C. At temperature below 90°C, the reaction proceeds slowly, and the rate of side processes increases above 140°C. The bases (alkali metal hydroxides and alcoholates) taken in 10%-50% amounts relative to cyclohexanone oxime serve as the reaction catalysts. The reaction is efficiently catalyzed by potassium, rubidium, and tetrabutylammonium hydroxides. It should be noted that the last two bases have a selective effect on the construction of the tetrahydroindole ring (synthesis of... 

Prehydrolysis method. Synthesis using binary mixtures of tetrabutylammonium and tetraethy-lammonium hydroxides instead of TPAOH Influence of TPAOH/TEAOH and TPAOH/NH4. 

A recent literature report described a green procedure for the condensation of arylacetonitriles with cyclic ketones using phase-transfer catalysis. This process was applied to the synthesis of venlafaxine, which was realized in overall 30% yield in two steps from commercially available 14. The condensation step was run in aqueous sodium hydroxide in the presence of tetrabutylammonium sulfate, to provide quantitative yield of intermediate 15. Hydrogenation in a formalin-methanol mixture provided the final product venlafaxine (1) in 30% overall yield. This protocol did not necessitate intermediate purification steps, making it attractive from the commercial standpoint. 

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