4-Hydroxymethylbenzoic acid

Phthalide. In a 1 litre bolt-head flask stir 90 g. of a high quality zinc powder to a thick paste with a solution of 0 5 g. of crystallised copper sulphate in 20 ml. of water (this serves to activate the zinc), and then add 165 ml. of 20 per cent, sodium hydroxide solution. Cool the flask in an ice bath to 5°, stir the contents mechanically, and add 73-5 g. of phthalimide in small portions at such a rate that the temperature does not rise above 8° (about 30 minutes are required for the addition). Continue the stirring for half an hour, dilute with 200 ml. of water, warm on a water bath imtil the evolution of ammonia ceases (about 3 hours), and concentrate to a volume of about 200 ml. by distillation vmder reduced pressure (tig. 11,37, 1). Filter, and render the flltrate acid to Congo red paper with concentrated hydrochloric acid (about 75 ml. are required). Much of the phthalide separates as an oil, but, in order to complete the lactonisation of the hydroxymethylbenzoic acid, boil for an hour transfer while hot to a beaker. The oil solidifles on cooling to a hard red-brown cake. Leave overnight in an ice chest or refrigerator, and than filter at the pump. The crude phthalide contains much sodium chloride. RecrystaUise it in 10 g. portions from 750 ml. of water use the mother liquor from the first crop for the recrystaUisation of the subsequent portion. Filter each portion while hot, cool in ice below 5°, filter and wash with small quantities of ice-cold water. Dry in the air upon filter paper. The yield of phthalide (transparent plates), m.p. 72-73°, is 47 g. 

TFA) in DCM (dichloromethane). Linkers for carboxylic acids have also been designed to effect cleavage via photolysis (3-nitro-4-hydroxymethylbenzoic acid, ONb 14) [18] and flouridolysis (N-3 or 4) ((4-hydroxymethyl)-phenoxy-t-butylphenylsilyl)phenyl pentanedioic acid monoamide (PBs) 15 [19] and quinonemethide-based handle 16 [20] (Fig. 

In 1996, Kim and coworkers reported for the first time on the use of a polyami-doamine (PAMAM) dendrimer [Gl] as a soluble support for organic synthesis (Fig. 7.5) [37]. Advantages of PAMAM are its commercial availability and its high symmetry, which provides uniform site accessibility (in lower generations) and facilitates NMR interpretation. By attaching 4-hydroxymethylbenzoic acid (HMB) to... 

Terephthalie acid can be reduced smoothly to 4-hydroxymethylbenzoic acid (potential intermediate for polyesters) in alkaline electrolytes ... 

In an intramolecular Cannizzaro the hydroxide-induced rearrangement of phthalaldehyde to o-hydroxymethylbenzoic acid (McDonald and Sibley, 1981), the pseudo first-order rate constant for appearance of product obeys equation (14). Phthalaldehyde exists as a cyclic hydrate [31] and the scheme... 

To develop the kinetics, let us take an A-B type of condensation monomer, such as p-hydroxymethylbenzoic acid. This monomer, if pure,... 

Many phenols have been tried, generally without success. A typical example is reported by Yilmaz, M. Vural, U. S. Synth. React. Inorg. Met.-Org. Chem. 1991, 21, 1231, who used 4-nitrophenol, 4-hydoxybenzoic acid, 4-hydroxyacetophenone, 1,4-dihydroxybenzene, 4-phenoxyphenol, 4-hydroxybenzyl alcohol, 4-cyanophenol, 4-hydroxymethylbenzoic acid and... 

Figure 4.1 Major oxidation intermediates from pX to TA. p-HMBA is p-hydroxymethylbenzoic acid, and 4-CBA is 4-carboxybenzaldehyde. Cat. Co-Mn-Br.

The use of 4-hydroxymethylbenzoic acid for routine preparation of peptide amides has been somewhat superseded by acid-labile linkage agents that liberate the amide with simultaneous cleavage of the peptide from the resin (7, 20). For preparation of peptide amides on a large scale, however, 4-hydroxymethylbenzoic acid is still favoured economically. 

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