Methyl 2- benzoat

The following liquids may be used (boiling points are given in parentheses) — chlorobenzene (132-3°) bromobenzene (155°) p cymene (176°) o-dichloro-benzene (180°) aniline (184°) methyl benzoate (200°) teti-alin (207°) ethyl benzoate (212°) 1 2 4-trichlorobenzene (213°) iaopropyl benzoate (218°) methyl salicylate (223°) n-propyl benzoate (231°) diethyleneglycol (244°) n-butyl benzoate (250°) diphenyl (255°) diphenyl ether (259°) dimethyl phth ate (282°) diethyl phthalate (296°) diphenylamine (302°) benzophenone (305)° benzyl benzoate (316°). 

The preparation of a number of miscellaneous acids is described. m-Nitrobenzoic acid. Although m-nitrobenzoic acid is the main product of the direct nitration of benzoic acid with potassium nitrate and concentrated sulphuric acid, the complete separation of the small quantity of the attendant para isomer is a laborious process. It is preferable to nitrate methyl benzoate and hydrolyse the resulting methyl w-nitrobenzoate, which is easily obtained in a pure condition ... 

Methyl m-nitrobenzoate. In a 1 htre round-bottomed or bolt-head flask, fitted with a mechanical stirrer, place 102 g. (94 ml.) of pure methyl benzoate (Section IV,176) support a separatory funnel containing a mixture of 62 -5 ml, of concentrated sulphuric acid and 62 -5 ml. of concentrated nitric acid over the mouth of the flask. Cool the flask in an ice bath to 0-10°, and then run in the nitrating mixture, with stirring. 

Ethyl benzoate sulphuric acid as a catalyst). Use 30 g. of benzoic acid, 115 g. (146 ml.) of absolute ethyl alcohol and 5 g. (2 7 ml.) of concentrated sulphuric acid. Reflux the mixture for 4 hours and work up as for Methyl Benzoate. The yield of ethyl benzoate, b.p. 212-214°, is 32 g. 

If an emulsion should form during the washing process, add about 10 ml. of carbon tetrachloride (for details, see under Methyl Benzoate,. Section IV,176). 

Mix 31 g. (29-5 ml.) of benzyl alcohol (Section IV, 123 and Section IV,200) and 45 g. (43 ml.) of glacial acetic acid in a 500 ml. round-bottomed flask introduce 1 ml. of concentrated sulphuric acid and a few fragments of porous pot. Attach a reflux condenser to the flask and boil the mixture gently for 9 hours. Pour the reaction mixture into about 200 ml. of water contained in a separatory funnel, add 10 ml. of carbon tetrachloride (to eliminate emulsion formation owing to the slight difference in density of the ester and water, compare Methyl Benzoate, Section IV,176) and shake. Separate the lower layer (solution of benzyl acetate in carbon tetrachloride) and discard the upper aqueous layer. Return the lower layer to the funnel, and wash it successively with water, concentrated sodium bicarbonate solution (until effervescence ceases) and water. Dry over 5 g. of anhydrous magnesium sulphate, and distil under normal pressure (Fig. II, 13, 2) with the aid of an air bath (Fig. II, 5, 3). Collect the benzyl acetate a (colourless liquid) at 213-215°. The yield is 16 g. 

The use of ether may be avoided by mixing the ester, after its isolation from the water layer, with about 20 ml. of carbon tetrachloride. The carbon tetrachloride solution then forms the lower layer in all washing operations (compare Methyl Benzoate, Section IV,176). 

Perbenzoic acid. Treatment of a cold sodium methoxide solution with a solution of pure benzoyl peroxide in chloroform affords methyl benzoate and a solution of the sodium salt of perbenzoic acid ... 

The methyl benzoate is removed by extraction with chloroform, and upon cautious acidification of the aqueous layer perbenzoic acid is liberated the latter is extracted with chloroform and is usually preserved as a solution in this solvent ... 

Methyl benzoate (isolated in 70% yield based on benzoic acid)... 

An important question about the mechanism of acid catalyzed esterification concerns the origin of the alkoxy oxygen For example does the methoxy oxygen m methyl benzoate come from methanol or is it derived from benzoic acid s... 

Notice that the oxygen of methanol becomes incorporated into the methyl benzoate product according to the mechanism outlined m Figure 19 7 as the observations of the Roberts-Urey experiment require it to be... 

C6H5COCH3 + CgHsCOH Methyl benzoate Benzoic acid... 

Methylpyrazine reacts with sodamide in liquid ammonia to generate the anion, which may be alkylated to give higher alkylpyrazines (Scheme 10) (61JOC3379). The alkylpyrazines have found extensive use as fiavouring and aroma agents (see Section 2.14.4). Condensation reactions with esters, aldehydes and ketones are common, e.g. methyl benzoate yields phenacylpyrazine in 95% yield, and reactions of this type are summarized in Scheme 11. 

The synthesis of pyrazolines and pyrazoles of the [CCNN + C] type with the creation of two bonds, N(2)-C(3) + C(3)-C(4) (or N(l)-C(5) + C(5)-C(4)), has been studied by several groups. Beam and coworkers have published a series of papers on the synthetic utility of lithiated hydrazones. Thus, the methylhydrazone of acetophenone (598) is converted by butyllithium into the dianion (599), which in turn reacts with methyl benzoate to afford the pyrazole (600) (76SC5). In earlier publications Beam et al. have used aldehydes and acyl chlorides to obtain pyrazolines and pyrazoles by the same method. 

The reaction of the dilithio salt (597) with methyl benzoate and subsequent acid hydrolysis yielded 3-phenyl-4,5,6,7-tetrahydro-2,1-benzisoxazole (598) (76JPS1408). The oxime (599) was converted into (600) by treatment with ethanolic HCl (75JCS(P1)1959>. 

Butanol 5ec-Butyl alcohol 86 C4Hi 0 Methyl benzoate 153 CgHgOj... 

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