Methyl p-anisate

Methylaminoacetaldehyde dimethyl acetal, d508 a-(l-Methylaminoethyl)benzyl alcohol, e2 Methylanilines, tl80 thru tl82 Methyl oanisate, m304 Methyl p-anisate, m305 2-Methyl-/ -anisidine, m80... 

As Figure 1 depicts, phenylalanine ammonia-lyase (PAL), which occurs ubiquitously in higher plants and the wood-rotting Basidiomycetes (1-3), seems to play a common central role in the conversion of phenylalanine (by deamination) to a wide variety of secondary metabolites. These include lignins in higher plants (4), veratryl alcohol in the white-rot fungus Phanerochaete chrysosporium (4a), and methyl p-anisate in the brown-rot fungus... 

Benzoic acid, 2-methoxy-, methyl ester. See Methyl o-methoxybenzoate Methyl o-anisate Benzoic acid, 4-methoxy-, methyl ester Benzoic acid, p-methoxy-, methyl ester. See Methyl p-anisate... 

Methyl o-anisate. See Methyl o-methoxybenzoate Methyl p-anisate... 

Methyl p-anisate o-Methylanisole p-Methylanisole Methyl anthranilate Methyl benzoate... 

Methoxy-4-vinylphenol Methyl abietate 4 -Methyl acetophenone Methyl acetylaminobenzoate Methyl amyl alcohol Methyl n-amyl ketone Methyl o-anisate Methyl p-anisate Methyl anthranilate 2-Methyl benzoxazole... 

The reaction was monitored by TLC (eluent petroleum ether-diethyl ether, 6 4). 2-Methyl-3-phenyl-2-propenol (UV active) visualized with a p-anisal-dehyde dip stained blue, Rt 0.50 and the epoxide stained brown, Rf 0.33. 

From organic synthesis point of view, two steps are involved in the production of p-anisic aldehyde from p-cresol, namely, methylation of p-cresol to PCME and oxidation of PCME to p-anisic aldehyde... 

PCME made by methylation of p-cresol using (CH3)2S04 or CH3CI in presence of NaOH has a well-defined odor of wall flowers with a definite suggestion of Ylang-Ylang. The compound is more known as an intermediate for manufacture of p-anisic aldehyde. Most of the PCME produced in the world is converted to p-anisic aldehyde. However, approximately 300 tpa are sold in the world market as a perfumery chemical. 

The most critical raw material for the production of Dilitiazem is p-anisic aldehyde. Approximately, 2.3-2.4 kg of /3-anisic aldehyde is required per kg of dilitiazem. Other important raw materials are D(+) alpha phenyl ethylamine (0.35kg/kg), 2-aminothiophenol (1.9kg/kg), methyl chloroacetate (1.9kg/kg), sodium methoxide (1.6kg/kg), chloroform (5.5kg/kg), methanol (9 kg kg), isopropyl alcohol (5kg/kg), etc. 

For some of the cresol derivatives such as p-anisic aldehyde based on oxidation of p-cresyl-methyl ether (PCME) using 80-82% Mn02 and sulfuric acid (80%) good quantities of spent MnSO4 along with excess acid are invariably produced and the waste streams have to be neutralized and solid Mn-sulfate has to be recovered towards waste minimization. 

This is the most important inorganic by-product formed during production of p-anisic aldehyde from p-cresol via the intermediate product p-cresyl-methyl ether (PCME). Manganese dioxide Mn02 (80-82%) in presence of sulfuric acid (80%) converts PCME to p-anisic aldehyde and a by-product stream rich in manganese sulfate and excess spent sulfuric acid used in the oxidation reaction as shown below ... 

It is reliably learnt that one Japanese company is using Co-acetate-Mn-acetate in a predetermined ratio for oxidation of PCME to p-anisic aldehyde. Similarly these mixed acetate catalysts have been used for oxidation of p-cresol to 7 -hydroxy benzaldehyde at a high pressure (say 10 kg/cm ) and also 3,4,5-trimethoxy benzaldehyde manufacture for conversion of the methyl group to aldehyde as discussed in Chapter 5. Use of this catalyst system is an established fact for oxidation of p-xylene to ptuified terephthalic acid (PTA) or dimethyl terephthalate. 

As in the case of many fine chemicals, waste minimization in the liquid streams is a must in the field of cresols and allied products. Many plants producing cresols from coal carhonization process have been closed down because of inherent problems of production of waste materials and byproducts. Same is the story with producers of p-anisic aldehyde using Mn02 as the catalyst. Some manufacturers found it economically not viable to recover both sodium sulfate and manganese sulfate from the waste streams involving etherification of para-cresol and oxidation of p-cresyl methyl ether. These plants were eventually closed down which has been discussed adequately in earlier chapters. 

Soon p-anisic aldehyde produced from p-cresol through the process of methylation of the hydroxy group and subsequent oxidation of the methyl group, turned out to be a very important organic chemical and an attractive outlet of p-cresol. p-Anisic aldehyde is effectively used for making octyl methoxy cinnamate (an UV-B sunscreen chemical) and dilitiazem (an antihypertension drug). Subsequently, a series of downstream derivatives of p-cresol have been synthesized and commercially produced. 

Treatment of tri-O-methylvitexin with hot, aqueous sodium hydroxide gives p-methoxyacetophenone and p-anisic acid, the side chain being removed from the aromatic nucleus but, with boiling aqueous barium hydroxide, an additional product, di-O-methyl-apovitexin, Ci4Hi607(0Me)2 is obtained. This ether, treated with an excess of aqueous periodic acid, gives 3-formyl-4,6-di-O-methylphloracetophenone, identical with a synthetic sample thereof. Oxidation of tri-O-methylvitexin with lead tetraacetate in acetic acid at room temperature for 5 days, or with dilute nitric acid at 100° for 1.5 hours, yields 8-formyl-tri-O-methylapigenin. These reactions, which lead to the partial structure (29) for vitexin, are summarized on p. 246. 

Synonyms o-Anisic acid, methyl ester Benzoic acid, 2-methoxy-, methyl ester Dimethyl salicylate o-Methoxybenzoic acid methyl ester o-M ethoxy methyl benzoate Methyl o-anisate Methyl 2-methoxybenzoate Methylsalicylate methyl ester Empiricai C9H10O3 Formuia CH3OC6H4CO2CH3 Properties M.w. 166.18 dens. 1.157 b.p. 248 C flash pt. > 230 F ref. index 1.5340 Toxicology LD50 (oral, rat) 3800 mg/kg, (skin, rabbit) > 5 g/kg mod. toxic by ing. si. toxic by skin contact TSCA listed Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating vapors Uses Synthetic flavoring agent in foods and pharmaceuticals... 

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