6-formyl-salicylic acid

Mahmoud, M.E. Soliman, E.M. Silica-immobilized formyl-salicylic acid as a selective phase for the extraction of iron(III). Talanta 1997,44 (1), 15-22. 

Transvalencin Z (245a) from Nocardia transvalensis could be a precursor or side product of mycobactin biosynthesis, possibly acquired from a vagabonding gene. It comprises the left part of the serine/salicylic acid based molecules (Table 5 R" = = H) and ends with A/ -formyl-Lys (R = H, no iV-hydroxy group). The... 

Miscellaneous Reactions. The Reimer-Tiemann reaction of salicylic acid (1) with chloroform and alkali (eq. 1) results in the 3- and 5-formyl derivatives. If the reaction is carried out with carbon tetrachloride, the corresponding dicarboxylic acids form (eq. 2). The products (2) and (3) are 2-hydroxy-l,3-benzenedicarboxylic acid [606-19-2] and 4-hydroxy-l,3-benzenedicarboxylic acid [636-46-4], respectively. 

New silica gel phases were synthesized by a single-step reaction via immobilization of 5-formyl-3-arylazosalicylic acid derivatives on the surface of silica gel. These phases proved to show an excellent improvement in the Fe(III) extraction the determined mmol/g is in the range 1.24—1.32. The process of selective extraction of Fe(III) in the presence of an interfering ion was studied by both column and batch equilibrium techniques. Cr(in) was found to cause interference based on the affinity for binding to the chelation centers of the salicylic acid moiety of the silica gel phase. Mg, Ca, and Mn ions exhibited minimum interference in Fe(III) extraction. A group of six divalent metal ions (Co, Ni, Cu, Zn, Cd, and Pb) were found to show a specific interference based on the availability and participation of arylazo-moiety. The structures of these silica gel phases-immobilized-5-formyl-3-arylazosalicylic acids are shown in Scheme 9. 

Use of n-butylamine in conjunction with nitromethane was found to be more effective than ammonium acetate/acetic acid in the preparation of 5-(2-nitroethenyl )salicylic acid from 5-formyl sail-... 

The use of these intermediates to produce shikimates is shown in Figure 6.32. In principle, anethole (53) and estragole (methyl chavicol) (52) are available from phenol, but in practice, the demand is met by extraction from turpentine. Carboxylation of phenol gives salicylic acid (38) and hence serves as a source for the various salicylate esters. Formylation of phenol by formaldehyde, in the presence of a suitable catalyst, has now replaced the Reimer-Tiemann reaction as a route to hydroxybenzaldehydes. The initial products are saligenin (189) and p-hydroxybenzyl alcohol (190), which can be oxidized to salicylaldehyde (191) and p-hydroxybenzaldehyde (192), respectively. Condensation of salicylaldehyde with acetic acid/acetic anhydride gives coumarin (50) and 0-alkylation ofp-hydroxybenzaldehyde gives anisaldehyde (44). As mentioned earlier, oxidation of phenol provides a route to catechol (184) and guaiacol (188). The latter is a precursor for vanillin, and catechol also provides a route to heliotropin (61) via methylenedioxybenzene (193). 

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