Benzilic acid methyl ester

Several conversions based on superelectrophilic hydroxycarbenium ions (such as 45) were also carried out at lower temperatures, including the condensation reaction (eq 41) and electrocyclization (eq 42).8,13 A similar electrocyclization reaction with a benzilic acid methyl ester was also found to proceed in high yield at —40°C (eq 43).22... 

Benzilic Acid, Methyl Ester A238 Precursor 154... 

Benzilic acid methyl ester. See Methyl benzilate Benzilidene acetone. See Benzylidene acetone 1H-Benzimidazol-2-amlne 2-Benzimidazolamine Benzimidazole, 2-amino-. See 2-Aminobenzimidazole Benzimidazole carbamate CAS 18538-45-9... 

CAS 76-89-1 EINECS/ELINCS 200-991-1 Synonyms Benzeneacetic acid, a-hydroxy-a-phenyl-, methyl ester Benzilic acid methyl ester Ethyl hydroxydiphenylacetate Ethyl 2-hydroxy-2,2-diphenylacetate Ethyl a-hydroxydiphenylacetate Ethyl a-phenylmandelate Hydroxydiphenylacetic acid, methyl ester Methyl benzillate Methyl diphenylglycolate Methyl hydroxy (diphenyl) acetate Methyl-2-hydroxy-2,2-diphenyl acetate Empirical C15HI4O3... 

P-Hydroxy-2P-tropanecarboxylic Acid Methyl Ester, Benzoate 3-Hydroxypropene 3-Hydroxyquinuclidine 3-Hydroxyquinuclidine Benzilate 3-(Mercaptomethyl)-l,2,3-benzotriazin-4(3H)-one 0,0-Dimethyl Phosphorodithioate 3-(Mercaptomethyl)-l,2,3-benzotriazin-4(3H)-one 0,0-Dimethyl Phosphorodithioate S-Ester 3-Methyl-4-(dimethylamino)phenyl Methylcarbamate... 

A mixture containing 8 g (0.06 mol) of N-methyl-3-chloro-piperidine and 13.6 g (0.06 mol) of benzilic acid in 50 cc of anhydrous isopropyl alcohol was refluxed for 3 days the isopropyl alcohol was removed by distillation in vacuo, the residue treated with dilute aqueous hydrochloric acid and the aqueous acid mixture extracted repeatedly with ether. The aqueous phase was separated, made strongly alkaline with 20% aqueous sodium hydroxide and extracted with ether. The ether extracts were dried with potassium carbonate and distilled the product was collected at 175° to 176°C (0.03 mm), yield 11.5 g (59%). The ester base thus prepared was then dissolved in 75 cc of isopropyl alcohol and 3.4 g (0.037 mol) methyl bromide added. The reaction mixture was allowed to stand at 30°C for 2 days and the product isolated by filtration, yield, 13 g (87%), MP 228° to 229°C dec. 

The diketo acids were transformed to their methyl esters under the action of diazomethane (5), SOCl2/CH3OH (102), or methanolic hydrogen chloride (117). Like other benzils, JV-methyloxohydrasteine (109) when... 

Benzidine, N,N -diethyl-, 36, 21 Benzidine dihydrochloride, 36, 22 Bcnzil, 34, 42 Benzil dihydrazone, 34, 42 Benzilic acid, 33, 37 2-Benzimidazolethiol, 30, 56 l,2-Benzo-3,4-dihydrocarbazole, 30, 91 Benzofuran, 3-methyl, 33, 43 Benzofurazan oxide, 31,14, 15 37,1 Benzoguanamine, 33,13 Benzoic acid, 32, 94 37, 21 Benzoic acid, -acetyl-, methyl ester, 32, 81... 

Mepenzolate Mepenzolate, 3-[(hydroxydiphenylacetyl)oxy]-l,1-dimethyl piperidinium bromide (14.1.13), is synthesized by esterification of benzilic acid with l-methyl-3-chloropiperidine and subsequent reaction of the resulting ester (14.1.12) with methyl bromide [14,15]. 

Sterically demanding benzilic acid was used to optimize the reaction conditions in respect to reagent excess and reaction time. Complete conversion (98%) of benzilic acid to the corresponding methyl ester was obtained with two equivalents of the methyl triazene resin 10 after 6 h 96% conversion was obtained when using the n-butyl triazene resin 10. The reaction between p-nitrophenylacetic acid (1 equiv., 2 mg/ml) and the polymer-supported triazene (2 equiv.) in DCM was monitored by HPLC. A 53% conversion from the acid to the ester product was observed after 5 min data analysis indicated a second-order reaction as observed in homogeneous solution. 

In the benzil analog (107) a benzilic acid rearrangement leading to the acid (108) can be done and the acid isolated either as a salt or as the methyl ester prepared with diazomethane at a low temperature. The surprise lies in the fact that the acid (108) is unexpectedly unstable in the free state what... 

Pipanzolate Bromide, /. i thyl-3.[(bydroxydiphe-n lacefyi />xy]-I -methylpiperidr ni u m bromide I-ethyf-3-hydroxy-1 -methylpipe rid in ium bromide benzilate benzilic acid, 1-ethyl-3-piperidyl ester methyl bromide JV-ethyl-3-... 

Benzeneacetic acid, 3-hexenyl ester, (Z)-. See cis-3-Hexenyl phenylacetate Benzeneacetic acid, o-hydroxy-o-phenyl-, methyl ester. See Methyl benzilate Benzeneacetic acid, 3-methylbutyl ester. See Isoamyl phenylacetate... 

In view of these results it is not surprising that even more sterically hindered carbonyl derivatives of Rf are also not accessible (22), An attempted synthesis of (Rf)2C0 from RpLi and dimethyl carbonate gave the methyl ester of 2,4,6-tris(trifluoromethyl)benzoic acid instead (25% yield). Similarly, treatment of RpLi with oxalyl dichloride did not yield the desired benzil derivative. In this reaction a 45% yield of 2,4,6-tris(trifluoromethyl ) -2-oxoethanoic acid, RfC(0)C00H, was obtained (22), All these experiments clearly demonstrate that in organic Rf chemistry steric hindrance is an important factor guiding the reactivity of various substrates. 

N-methyl-4-piperidvl benzi/ata and the methiodide An intimate mixture of 0.1 mol of N-methyM-piperidinol hydrochloride and 0.1 mol diphenylchloroacetyl chloride is heated at 160°C to 180°C until the evolution of hydrogen chloride ceases (usually about 4 to 5 hours). The melt is then dissolved in 500 ml of water and the resultant mixture heated on a steam bath for about Vi hour, after which time complete solution is effected. The acid solution is cooled and rendered alkaline with ammonium hydroxide solution whereupon the ester is precipitated.The ester is purified either by removal by filtration and recrystallization from benzene petroleum ether or by extracting the mixture with benzene and precipitating the ester by the addition of petroleum ether. After recrystallization there is obtained about 0.06 mol of N-methyl-4-piperidyl benzilate, melting point 1 62°C to 163°C. 

Reaction of carboxylate ion with nitrophenyl sulfites gives the carboxylate />-nitrophenyl esters. If the y>-nitrophenyl sulfite is unsymmetncal (02NC6H40S(0)0R, where R is ethyl or phenyl), carboxylate attacks the/>-nitrophenyl side (69). Some amino acids react with methyl and benzyl sulfites in the presence of y>-toluenesulfonic acid to give methyl and benzyl esters of the amino acids as />-toluenesulfonate salts (70). With alcohols, the conversion of benzil to a monoacetal upon addition of sulfuric acid to the benzil in methanol and dimethyl sulfite proceeds in high yield (71). 

Cyanocarboxylic acid esters. 2-Oximinocyclohexanone dimethyl ketal, trimethyl orthoformate, and a little methanesulfonic acid added at -70° under Ng to liq. SO2, and refluxed 0.5 hr. at ca. -10° methyl 5-cyanopentanoate. Y 97%. -Similarly at 72° Benzil monoxime and triethyl orthoformate -> benzonitrile (Y 95%) and ethyl benzoate (Y 98%). M. M. Rogic et al., J. Org. Chem. 39, 3424 (1974) Beckmann fragmentation with tetrakis(triphenylphosphine)palladium cf. K. Maeda et al., Chem. Commun. 1975, 689. 

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