Tert Butyl -toluenesulfonate

C41H61AIN2O7S, Aluminum, dimethanol-1,2-bis(2-hydroxy-3,5-bis(tert-butyl)benzyhde-neimino)ethane-, pura-toluenesulfonate, 34 18... 

O6F12RUC12H2, Ruthenium, dicarbonylbis(hexa-fluoroacetylacetonato)-, 34 115 O6NVC14H20, Vanadate(l-), hexacarbonyl-, tetraethylammonium, 34 98 O7AIN2SC41H61, Aluminum, dimethanol-1,2-bis(2-hydroxy-3,5-bis(tert-butyl)benzylide-neimino)ethane-, para-toluenesulfonate, 34 18... 

The final, critical oxidative spirocyclization of the 2,3-disubstituted indole to the spiro oxindole was effected by treatment of 124 with tert-butyl hypochlorite in pyridine to provide the labile 125 [Fig. (34)]. The Pinacol-type rearrangement was conducted by treating compound 125 with p-toluenesulfonic acid in THF/water. It is assumed that the chlorination of 124 proceeds from the least hindered face of the indole, to give the a-chloroindolene 125. The hydration of the imine functionality must also occur from the same a-face that is syn to the relatively large chlorine atom furnishing the syn-chlorohydrin 126, that subsequently rearranges stereospecifically to the desired spiro oxindole 127. 

ButylatedPhenols and Cresols. Butylated phenols and cresols, used primarily as oxidation inhibitors and chain terminators, are manufactured by direct alkylation of the phenol using a wide variety of conditions and acid catalysts, including sulfuric acid, -toluenesulfonic acid, and sulfonic acid ion-exchange resins (110,111). By use of a small amount of catalyst and short residence times, the first-formed, ortho-alkylated products can be made to predominate. For the preparation of the 2,6-substituted products, aluminum phenoxides generated in situ from the phenol being alkylated are used as catalyst. Reaction conditions are controlled to minimize formation of the thermodynamically favored 4-substituted products (see Alkylphenols). The most commonly used is -/ -butylphenol [98-54-4] for manufacture of phenolic resins. The tert- butyl group leaves only two rather than three active sites for condensation with formaldehyde and thus modifies the characteristics of the resin. 

In Fig. (12) keto ester (94) was selected as starting material. It was converted to the formyl derivative (95) which yielded a,P-unsaturated aldehyde (96) by treatment with DDQ. Michael addition of the sodium enolate of tert-butyl- isovalerylacetate to aldehyde (96) afforded the adduct (97) as a mixture of C-ll diastereomers. By fractional crystallization one of the adducts could be separated but for the synthetic purpose the mixture was not separated. Treatment of the adduct (97) with p-toluenesulfonic acid in glacial acetic acid caused t-butyl ester cleavage, decarboxylation and cyclodehydration leading the formation of tricyclic enedione (98) in 80% yield. This approach was previously utilized by Meyer in the synthesis of nimbiol [29], Treatment of (98) with pyridinium bromide perbromide, followed by hydrogenolysis with palladium and carbon caused aromatization of (98) leading the formation of the phenolic ester (99). 

A mixture of 1,8-naphthalenediamine (3.48 g, 22 mmol), 2-tert-butyl-1,4-naphthoquinone (3.21 g, 15 mmol) and p-toluenesulfonic acid (50 mg) was melted together at 165-170°C for 4 h, cooled to room temperature and dissolved in chloroform (20 ml). The solution was passed through a column (40 x 3.5 cm) filled with A120 3. The column was washed with chloroform-hexane (1 3) and the fraction of orange color collected. After evaporation of the solvent, dark-yellow crystals of 2,3-dihydro-2-spiro-4 -[(4H)-2 -fert-butlnaphthalen-l -one]perimidine (2.06 g, yield 47.8%) were obtained, mp 211-213°C (after recrystallization from methanol and heptane). 

The following chemicals were purchased from Kanto Chemical Co. Inc. and used as received neopentyl glycol, p-toluenesulfonic acid, sodium, and n-BuLi. N,N,N, N -Tetramethylethylenediamine was purchased from Aldrich Chemical Company, Inc. and distilled before use. 1,3-Dichloroacetone was obtained from Wacker Chemicals East Asia and used as received. Reagent grade benzene, pentane, ether, THE, tert-butyl alcohol, acetonitrile, and toluene were purchased from Wako Chemicals Industries Ltd. Benzene, pentane, and tert-butyl alcohol were distilled from CaH ether and THF from sodium benzophenone ketyl immediately before use acetonitrile successively from PjOj and anhydrous KjCOj and toluene from LiAlH. Potassium tert-butoxide and 2-cyclopenten-1-one were purchased from Tokyo Kasei Kogyo Co. Ltd. the ketone was distilled before use. 

Substituted oxazolidin-5-one derivatives, which are prepared from N -protected a-annino dicarboxyhc acids and paraformaldehyde, are employed for dual protection of the a-annino and a-carboxy groups in the synthesis of P-aspartyl and y-glutamyl esters (Scheme 4).Py For this purpose the oxazolidinone derivatives are synthesized by treatment of the Z amino acids with paraformaldehyde in a nnixture of acetic anhydride, acetic acid, and traces of thionyl chloride or by azeotropic distillation of the Z amino acids with paraformaldehyde and 4-toluenesulfonic acid in benzene. The resulting heterocychc compounds are readily converted into the tert-butyl esters with isobutene under acid catalysis. Esterification is achieved with tert-butyl bromidet or with Boc-F.P l Finally, the oxazolidinone ring is opened by alkaline hydrolysis or catalytic hydrogenolysis to yield the tert-butyl esters. 

A simple one-pot procedure for the synthesis of Fmoc-protected aspartic and glutanoic acid tert-butyl esters is shown in Scheme tert-Butylation of unprotected Asp and Glu can be effected in dioxane with excess isobutene using 4-toluenesulfonic add as catalyst. Subsequent Fmoc derivatization results in a mixture of the mono-tert-butyl esters (co/a 65/35 for Glu and 50/40 for Asp) with an overall yield of 55-60% contaminated with small amounts of d -tert-butyl esters. This procedure has the advantage that the Fmoc group is introduced without prior isolation or purification of the aspartic and glutamic tert-butyl esters. Whilst the diesters are readily removed by extraction with organic solvents, the Fmoc-Asp/Glu(OtBu)-OH derivatives are isolated by crystallization from dichloromethane/petroleum ether. 

The tert-butyl ethers of serine and threonine are available by tert-butylation of various starting materials, e.g. Z-Ser-OMe/Z-Thr-OMe,P l Z-Ser-ONbz/Z-Thr-ONbz,P l and H-Ser-OMe TosOH/H-Thr-OMe -TosOHt l (see also Table 3). Analogous to benzyl ether formation, the tert-butyl ethers can also be produced via 4-substituted 2,2-difluoro-l,3,2-ox-azaborolidin-5-ones.t In most cases, isobutylene with 4-toluenesulfonic add, or a concentrated inorganic acid is used as catalyst for tert-butylation. The use of Fmoc-Ser(tBu)-OH and Fmoc-Thr(tBu)-OH in solid-phase peptide synthesis is very well established. These annino acid derivatives can be synthesized either by introduction of the Fmoc group into H-Ser(tBu)-OH and H-Thr(tBu)-OH or by tert-butylation of the Fmoc-protected serine and threonine (Table 3). ... 

Abbreviations Ac acetyl Bn benzyl BSP 1-benzenesulfinyl piperidine BTIB bis(trifluoroacetoxy)iodobenzene DAST (diethylamino)sulfur trifluoride DDQ 2,3-dichloro-5,6-dicyano-/)-benzoquinone DMDO dimethyldioxirane DMTSF dimethyl(methylthio)sulfonium tetrafluoroborate DMTST dimethyl(methylthio)sulfonium triflate DTBMP 2,6-Ai-tert-butyl-4-methylpyridine DTBP 2,6-di-tert-butylpyridine DTBPl 2,6-di-tert-butylpyridinium iodide FDCPT l-fluoro-2,6-dichloropyridinium triflate FTMPT l-fluoro-2,4,6-trimethylpyridinium triflate IDCP iodonium dicollidine perchlorate IDCT idonium dicollidine triflate LPTS 2,6-lutidinium p-toluenesulfonate LTMP lithium tetramethylpiperidide Me methyl MPBT S-(4-methoxyphenyl) benzenethiosulflnate NBS A-bromosuccinimide NIS A-iodosuccinimide NlSac A-iodosaccharin PPTS pyridinium p-toluenesulfonate TBPA tris(4-bromophenyl)ammoniumyl hexachloroantimonate Tf trifluoromethanesulfonyl TMTSB methyl-bis(methylthio)sulfonium hexachloroantimonate TMU tetramethylurea Tr trityl TTBP 2,4,6-tri-tert-butylpyrimidine. 

In the presence of catalytic amounts of p-toluenesulfonic acid, D-galactose diethyl dithioacetal (112) reacts248 with tert-butyl vinyl ether to afford the 5,6-O-ethylidene derivative 113 in 56% yield Wolfram and Parekh248 proposed that the reaction proceeds by initial, electrophilic addition of 0-6 to the double bond, followed by pro-... 

The supposition that a carbonium ion is formed as an intermediate in these reactions is still further supported by the observation that when ferZ-butyl esters are treated with sulfuric acid in dioxane solution, isobutylene is formed, and the process is completely reversible.15 Similarly, the reaction of tert-butyl benzqate with acetic acid in the presence of p-toluenesulfonic acid gave a small amount of isobutylene.16... 

N-tert-Butoxyoarbonyl-L-serine Serine, N-carboxy-, N-tert-butyl ester, L- (8) L-Serine, N[(1,1-dimethylethoxy)carbonyl]- (9) (3262-72-4) p-Toluenesulfonic acid monohydrate (8) Benzenesulfonic acid, 4-methyl-, monohydrate (9) (6192-52-5)... 

Benzoyl tert-butyl peroxide 353 211-522-5 Sodium p-toluenesulfonate 3524... 

Esterification can be performed smoothly and in high yields with tert-butyl ethers. - E Pyruvic acid refluxed 1-1.5 hrs. with n-butyl tert-butyl ether until evolution of isobutylene ceases n-butyl pyruvate. Y 86%. - H2SO4 or p-toluenesulfonic acid is used as catalyst for less active acids. F. e. s. V. A. Derevitskaya, E. M. Klimov, and N. K. Kochetkov, Tetrah. Let. 1970, 4269. 

Benzene, iV AT-dimethylfcnmamide (DMF), dichlorometiiane, metiiyl methacrylate, tert-butyl methacrylate (TBMA) and p-terT-butoxystyrene (tBOSt) were purchased and distilled before use. 2,2 -Azobisisobutyronitrile (AIBN) was purified by recrystallization from etiianol. 9-Fluorenilideneimino p-toluenesulfonate (FITS) (72), neopentyl styrenesulfonate (NPSS) (73), cyclohexyl styrenesulfonate (CHSS) (14) and phenyl styrenesulfonate (PhSS) were prepared according to the lito ture. Qxone (potassium... 

---