Trimethyl hydrolysis

The structure of compound A was established in part by converting it to known compounds Treat ment of A with excess methyl iodide in the presence of silver oxide followed by hydrolysis with dilute hydrochlonc acid gave a tnmethyl ether of D galactose Companng this trimethyl ether with known trimethyl ethers of D galactose allowed the structure of compound A to be deduced... 

Trimethyl aluminum and propylene oxide form a mixture of 2-methyl-1-propanol and 2-butanol (105). Triethyl aluminum yields products of 2-methyl-1-butanol and 2-pentanol (106). The ratio of products is determined by the ratio of reactants. Hydrolysis of the products of methyl aluminum dichloride and propylene oxide results ia 2-methylpropeae and 2-butene, with elimination of methane (105). Numerous other nucleophilic (107) and electrophilic (108) reactions of propylene oxide have been described ia the Hterature. 

The basic hydrolysis of tri alkyl tin haUdes and other salts forms bis(oxide)s since, except for trimethyl tin, hydroxides are unstable towards dehydration at room temperature. With tin aryl, aralkyl, and cycloalkyltin compounds, the hydroxides can be isolated. Although quite stable, they exist in mobile equiUbrium with the bisoxide and water and are easily dehydrated. Trimethyl tin hydroxide is exceptionally stable towards dehydration. 

Phenylstibine [58266-50-5] C H Sb, has been obtained by the reduction of phenyldiio do stihine [68972-61-2] CgH3l2Sb, (73) or phenyldichlorostibine [5035-52-9] 031130.2, (74) with lithium borohydride. It has also been prepared by the hydrolysis or methanolysis of phenylbis(trimethylsilyl)stibine [82363-95-9] C22H23Si2Sb (75). Diphenylstibine [5865-81-6] C22H22Sb, can be prepared by the interaction of diphenylchlorostibine [2629-47-2] C22H2QClSb, with either Hthium borohydride (76) or lithium aluminum hydride (77). It is also formed by hydrolysis or methanolysis of diphenyl (trimethylsilyl)stibine [69561-88-2] C H SbSi (75). Dimesitylstibine [121810-02-4] h.3.s been obtained by the protonation of lithium dimesityl stibide with trimethyl ammonium chloride (78). The x-ray crystal stmcture of this secondary stibine has also been reported. 

An earlier procedure for the production of choline and its salts from natural sources, such as the hydrolysis of lecithin (23), has no present-day apphcation. Choline is made from the reaction of trimethyl amine with ethylene oxide [75-21-8] or ethylene chlorohydrin [107-07-5J. 

Imidazole, 2,4,5-trichloro-1-methyl-chlorination, 5, 398 Imidazole, 2,4,5-trideutero-iodination, 5, 401 Imidazole, 1-trifiuoroacetyl-reactions, 5, 451-452 Imidazole, 2-trifiuoromethyl-hydrolysis, 5, 432 Imidazole, 2,4,5-triiodo-nitration, 5, 396 synthesis, 5, 400 Imidazole, 1,2,4-trimethyl-photolysis, 5, 377 rearrangement, 5, 378 Imidazole, 1,2,5-trimethyl-photochemical rearrangement, 5, 377 rearrangement, 5, 378 Imidazole, 1,4,5-trimethyl-bromination, 5, 399 3-oxide... 

Steiic effects of another kind become important in highly branched substrates, in which ionization is facilitated by relief of steric crowding in going from the tetrahedral groimd state to the transition state for ionization. The ratio of the hydrolysis rates in 8OV0 aqueous acetone of t-butyl /F-nitrobenzoate and 2,3,3-trimethyl-2-butyl p-nitrobenzoate is 1 4.4. 

The hydrolysis of aspirin [Eq. (6-70), R = CH3] is a classic example demonstrating a sigmoid pH-rate effect. Figure 6-13 shows this curve for trimethyl-... 

Tlie synthesis concludes by the route pioneered by Eschenmoser. Itromination of 47 proceeds at the position a to the tropolone I ing to give 48. Displacement of halogen by ammonia followed by liase hydrolysis of the tropolone methyl ether gives trimethyl-lolchicinic acid. Acetylation of the amine followed by reesteri-... 

Phosphates. Insoluble orthophosphates may be precipitated with phosphate ion derived from trimethyl or triethyl phosphate by stepwise hydrolysis. Thus 1.8M sulphuric acid containing zirconyl ions and trimethyl phosphate on... 

Acid hydrolysis of 2-ethoxy-3,5.7-trimethyl-3//-azepine (1) yields the dihydrofuran-2(3//)-one... 

Likewise, 2,3,4-trimethyl-6,7,8,9-tetrahydro-3//-3-benzazepine-l, 5-dicarbonitrile on prolonged refluxing in xylene is converted into the imine 22 which, during workup, suffers hydrolysis to the ketone 23.126... 

Very few optically active cyanohydrins, derived from ketones, are described in the literature. High diastcrcosclectivity is observed for the substrate-controlled addition of hydrocyanic acid to 17-oxosteroids27 and for the addition of trimethyl(2-propenyl)silane to optically active acyl cyanides28. The enantioselective hydrolysis of racemic ketone cyanohydrin esters with yeast cells of Pichia miso occurs with only moderate chemical yields20. 

Similarly, 2,3,5-trimethyl-1,4-hydroquinone (TMHQ), a key intermediate in the synthesis of vitamin E, is produced via oxidation of 2,3,6-trimethylphenol to the corresponding benzoquinone. Originally this was performed by reaction with chlorine followed by hydrolysis, but this process has now been superseded by oxidation with O2 in the presence of a Cu2Cl2/LiCl catalyst (see Fig. 2.20) (Mercier and Chabardes, 1994). Alternatively, this oxidation can also be cataly.sed by a heteropolyanion (Kozhevnikov, 1995). 

Bamard PWC, Bunton CA, Llewellyn DR, et al. 1961. The reactions of organic phosphate Part V. The hydrolysis of triphenyl and trimethyl phosphates. J Chem Soc 2670-2676. 

Methylation of X with silver oxide and methyl iodide gave the lactone of methyl 2,5-dimethyl-j8-D-glucofururonoside (XIII) which was characterized by its conversion to the crystalline amide (XIV). Further methylation of XIII, form, with methyl sulfate and sodium hydroxide gave methyl 2,3,5-trimethyl-/3-D-glucofururonoside (XVI) from which by hydrolysis of the glycosidic methyl group and subsequent oxidation with bromine, there was obtained 2,3,5-trimethyl-D-glucosaccharolactone (XVII) characterized by the formation of its crystalline methyl ester. 

It was found possible to saponify ovomucoid with sodium hydroxide and to methylate simultaneously with methyl Bulfate, the carbohydrate residue thereby forming an N-acetyl methyl derivative.14 Hydrolysis of this material yielded N-acetyl-3,4,6-trimethyl-D-glucosamine (7 moles) (LIVJ, D-mannopyranose (2 moles) (LV), 3,4,6-trimethyl-D-mannopy-ranose (1 mole) (LVI), and tetramethyl-D-galactopyranose (1 mole) (LVII). 

---