Mandelic acid chemistry

The oxidation of phenylethyne with isolated dimethyldioxirane gives mandelic acid (61) and phenylacetic acid (60) as the main products.115 The formation of (60) and (61) is explained as involving the initial formation of phenyloxirene and therefore dimethyldioxirane-mediated oxidation of alkynes is potentially suited to study the chemistry of the elusive oxirenes. 

As would be anticipated for a carboxylic acid, mandelic acid is known to exhibit a pH strong dependence in its aqueous solubility. This pH dependence was calculated using the solubility module of the ACD PhysChem computational program (version 6.0, Advanced Chemistry Development, Toronto, Canada), and these results are plotted in Figure 1. The results indicate that mandelic acid will be freely soluble in basic solution, which would be interpreted to imply that the sodium salt would be freely soluble as well. 

The Merck Index lists the melting point of racemic mandelic acid as 119°C [1], while the Handbook of Chemistry and Physics gives the melting point range as 121-123°C [14], The United States Pharmacopeia specifies the wider range of 118-121°C for the melting point range [15]. 

The H-NMR spectrum of mandelic acid is fairly simple, and its resonance bands and assignments are summarized in Table 4. The 13C-NMR spectrum is also simple, and the analogous information is also summarized in Table 4. The information was calculated using the SpecManager Program (Advanced Chemistry Development, Toronto, Canada). 

Rule-based or systematic nomenclature (e.g., International Union of Pure and Applied Chemistry [IUPAC] or CAS nomenclature) is based on a set of linguistic rules that apply to its structure. For example, the IUPAC and CAS names for mandelic acid are 2-phenyl-2-hydroxyacetic acid and benzeneacetic acid, a-hydroxy-, respectively. The number of possible systematic names is practically endless. A small, but not nearly exhaustive, set of other systematic names includes phenylglycolic acid, phe-nylhydroxyacetic acid, ( )-a-hydroxybenzeneacetic acid, ( )-a-hydroxyphenylacetic acid, ( )-2-hydroxy-2-phenylethanoic acid, ( )-Mandelic acid, (RS)-Mandelic acid, DL-Amygdalicacid,DL-Hydroxy(phenyl)aceticacid,DL-mandelicacid,paramandelic acid, a-hydroxy- a-toluic acid, a-hydroxyphenylacetic acid, a-hydroxybenzeneacetic... 

Figure 13.18 Immobilization chemistry and its impact on enantioseparation selectivity of DNB-Leu, mandelic acid, and dichloroprop on cinchona 9-O-carbamate-based CSPs. Chromatographic conditions mobile phase MeOH 0.1 M NH4OAc AcOH 98 2 0.5 v/v/v, 1 ml/min, I = 10cm for Cll linkers [102], MeOH 0.1 M NH4OAc 80 20 v/v pHa 6, 1 ml/min, I = 15 cm for C9 linker [103],...

Fig.ll A selection of chiral mandelic acids with applications in fine chemistry. 

Even more famous is Seebach s related chemistry on hydroxy acids10 such as lactic and mandelic acids from the chiral pool (chapter 23). Mandelic acid 78 gives the cis pivaldehyde acetal 79 in 74% yield after a recrystallisation to remove a small amount of the anti isomer. The lithium... 

Mandelic acid is a -hydroxyl phenyl acetic acid. Mandelic acid and its derivatives are very useful in medicinal chemistry some of them have been used in pharmaceutical applications. A few methods have been developed to synthesize mandelic acid and even optically pure mandelic acid. Shown here is the general method for the preparation of mandelic acid from benzaldehyde and sodium cyanide. 

Asymmetric Diels-Alder reactions with dienes bearing chiral auxiliaries have been studied less extensively. One example exploits some interesting cycloreversion chemistry. [52] The source of asymmetry for diene (120) is (5)-mandelic acid. 

S. Mandeles, Nucleic Acid Sequence Analysis, Columbia University Press, New York, 1972. N. K. Kochetkov and E. I. Budovskii, Organic Chemistry of Nucleic Acids, Plenum, London,... 

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