M-phenoxybenzaldehyde

Similarly, Mitsubishi scientists developed commercial processes for the manufacture of aldehydes such as the agrochemical intermediate, m-phenoxybenzaldehyde, and the fragrance intermediate, /p-rcrt-butylbenzaldehyde, by vapour-phase hydrogenation of the corresponding carboxylic acids over zirconia or chromia catalysts (Eqn. (6)) (Yokoyama et ai, 1992). 

Sonawane et al. (Sonawane et al., 1994) described a practical and efficient synthesis of fenoprofen using commercially available m-phenoxybenzaldehyde as the starting material. The key step in the synthesis is the transformation of the a-hydroxyacetal (i) into its chlorosulfonyl ester in situ and its concomitant rearrangement to the methyl ester (ii) in high yields. The required a-hydroxyacetal (i) can be readily prepared from m-methoxybenzaldehyde by the routine sequence of reactions Grignard reaction with ethyl bromide or chloride, oxidation and finally a-chlorination with CuCI2-LiCI/DMF. 

Sumitomo 506) has described the electrosynthesis of m-phenoxybenzaldehyde in a patent application ... 

Asymmetric synthesis by means of a cyandiydrin is an imprvtant process in organic synthesis, because the cyanohydrin can be easily converted into a variety of valuable synthetic intermediates, such as a-hy-droxy ketones, a-hydroxy acids, y-diketones, p-amino alcohols, 4-oxocarboxylic esters, 4 xonitriles, a-amino acids and acyl cyanides. More specifically, the (S)-cyanohydrin of m-phenoxybenzaldehyde is a building block for the synthesis of the insecticide deltamethrin, or (IR)-cis-pyrethroids. ... 

A further important asymmetric biocatalytic synthesis represents the hydrocyanation of aldehydes [116] for the production of cyanohydrins which are intermediates for a broad variety of life science molecules. For example, (/ )-mandelonitrile is a versatile intermediate for the synthesis of ( )-mandelic acid, and (S)-m-phenoxybenzaldehyde cyanohydrin is a building block for the preparation of pyrethroids. 

For the production of (5)-m-phenoxybenzaldehyde cyanohydrin (47) DSM established an enzymatic hydrocyanation process on an industrial scale (Scheme 31). An efficient (S)-oxynitrilase biocatalyst has been developed. This enzyme is derived from the plant Hevea brasiliensis, and has been cloned and overexpressed in a microbial host organism [117]. In the presence of this biocatalyst the desired product 47 has been obtained with high enantioselec-tivity. 

The cuiTent process for producing aromatic and aliphatic aldehydes by direct hydrogenation of the corresponding carboxylic acids over Zr02 and Cr203 has been developed by the Mitsubishi Chemical Corporation. It has successfully commercialized the production of p-t-butylbenzaldehyde, m-phenoxybenzaldehyde, p-methylbenzaldehyde, 10-undecenal, and dodecanal by reduction of the corresponding acids. By use of this technology, ca. 2000 t y of aldehydes have been manufactured since 1988 [3]. 

Beilstein Handbook Reference) Benzaldehyde, 3-phenoxy- BRN 0511662 EINECS 254-487-1 m-(Phenyloxy)benzaldehyde 3-Phenoxybenz-aldehyde m-Phenoxybenzaldehyde. 

PTC condensation of 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid chloride with m-phenoxybenzaldehyde cyanohydrin PTC Benzyltriethylammonium chloride (TEBAC)... 

Another important derivative of m-cresol used in the manufacture of plant protection agents is m-phenoxytoluene, which can be produced from m-cresol and chloro- or bromobenzene at temperatures of 200 °C, with copper catalysts. m-Phenoxytoluene is converted into m-phenoxybenzoic acid methyl ester by oxidation with a cobalt acetate/KBr catalyst and subsequent esterification m-phenoxybenzoic add methyl ester serves as an intermediate in the production of m-phenoxybenzaldehyde, which is used as the raw material in the production of the synthetic pyrethroid insecticide, fenvalerate (see Chapter 6.3.2). The cyanohydrin is formed in-situ, then made to react with 2-isopropyl-(4-chlorophenyl) acetic acid chloride to yield fenvalerate, which was developed by Sumitomo Chemical in 1972. Pyrethroid insecticides are distinguished by their low toxicity and high activity. 

Other important pyrethroid insecticides based on m-phenoxybenzaldehyde are deltamethrin (Roussel-Udaf) and the chlorine analogue cypermethrin. 

Monobromobenzaldehyde, an intermediate for the manufacture of the pesticide m-phenoxybenzaldehyde, is produced in a batch reactor. Due to side reactions, the productivity is about 15.5kg/m /hr. If made in a continuous reactor, the same process productivity increases to 34.5kg/m /hr. 

Many electrochemical approaches to biaryls, e.g., electroreductive dimerization of aryl halides [12, 13] and electrooxidative dimerization of arylboronic acids [14], have been investigated. Substituted or non-substituted benzoic acids are electrochemically reduced to the corresponding alcohols or aldehydes. For instance, electroreduction of /M-phenoxybenzoic add proceeds smoothly to afford m-phenoxybenzaldehyde, an intermediate for insecticide [2,15]. 

The effect of hydrotropes on the crossed Cannizzaro reaction rate of benzaldehydes with aqueous formaldehyde was investigated [67]. In the presence of polyethyleneglycol-200 the reaction rate of w-phenoxybenzalde-hyde increases more than six-fold and the w-phenoxybenzyl alcohol is also obtained with higher selectivity. The enhancement of the reaction rate of m-bromobenzaldehyde is lower than that observed for m-phenoxybenzaldehyde but the reaction selectivity is higher. p-Anisaldehyde and p-chlorobenzalde-hyde show an intermediate behavior. The cationic surfactants cetylpyri-dinium chloride and cetyltrimethylammonium bromide (CTABr) favor the Cannizzaro reaction instead of the crossed Cannizzaro one. 

---