Glycolic acid synthesis

I. Zelitch, J. Biol Chem., 240 1869-1876 (1965). The Relation of Glycolic Acid Synthesis to the Primary Photosynthetic Carboxylation Reaction in Leaves. 

Zehtch, L The relation of glycolic acid synthesis to the primary photosynthesis producing reaction in leaves J. Biol. Chem. 240 (1965) 1869-1876. 

The preceding discussions of the kinetics and molecular weight distributions in the step-growth polymerization of AB monomers are clearly exemplified by the esterification reactions of such monomers as glycolic acid or co-hydroxydecanoic acid. Therefore one method for polyester synthesis is the following ... 

Chemical Properties. Trimethylpentanediol, with a primary and a secondary hydroxyl group, enters into reactions characteristic of other glycols. It reacts readily with various carboxyUc acids and diacids to form esters, diesters, and polyesters (40). Some organometaUic catalysts have proven satisfactory for these reactions, the most versatile being dibutyltin oxide. Several weak bases such as triethanolamine, potassium acetate, lithium acetate, and borax are effective as stabilizers for the glycol during synthesis (41). 

The synthesis of high-molar-mass PLA and PGA by two-step polycondensations of lactic and glycolic acids, respectively, has recently been reported.374,375 It involves the formation of a low-molar-mass oligomer followed by a polycondensation step either in the solid state374 or in the melt under vacuum.375 The procedures are detailed in Section 2.4.1.5.2. 

Poly (glycolic acid) (PGA), 41, 42, 85 preparation of, 99 Polyheterocyclization concept, 265 Poly(hexafluorobisphenol-A), 361 Poly(hexamethylene adipamide), 5 Poly(hexamethylene adipate), 5 Poly(hexamethylene fumarate) synthesis, 100-101... 

Azelaic acid is a non-phenolic derivative (1,7-hep tanedicarboxylic acid) used at concentration of 10-20% twice a day to treat melasma with minimal side effects (allergic reactions). It acts to disturb the tyrosinase synthesis and can be used as a bleaching agent in patients sensitive to hydroquinone. Better results are obtained if a glycolic acid cream is applied sequentially to azelaic acid treatment. 

Figure 13.1.1 The synthesis of poly(glycolic acid) (PGA) from the dimer of glycolic acid.

Glycolic acid for synthesis of indole-3-acetic acid, 44, 64... 

Scheme 10.1 Glycopeptide synthesis and a-chymotrypsin catalyzed release from the solid support, a) 25% TFA (CH2CI2) b) 0-(N-Boc-Phe)glycolic acid (7 eq), BOP, HOBt, DIEA b) 25% TFA (CH2CI2) c) Boc-Gly-OH (7 eq), BOP, HOBt, DIEA c) 25% TFA (CH2CI2) d) Boc-Asn(GlcNAcb)-OH (3 eq), BOP, DIEA e) galactosyl transferase, sialyl transferase f) CT, H2O, pH 7.0 g) ultrafiltration h) a-l,3-fuco-syltransferase, GDP-Fuc (2.5 eq), 0.1 M HEPES (pH 7.0), 95%.

Diez E, Dixon DJ, Ley SV, Polara A, Rodriguez F, The use of butane diacetals of glycolic acid as precursors for the synthesis of the phyto toxic calmodulin inhibitor herbarumin II, Helv ChimActa 86 3717—3729, 2003. 

Furyl)glycolic acid (605), a substrate for the synthesis of hex-oses (see Section IV) was resolved119 into both enantiomeric forms by recrystallization of its 2(R)-menthyl ester. From the R enantiomer of 605, methyl a-D-glucopyranoside320 and methyl a-D-mannopyrano-side227 were obtained by a sequence of reactions discussed in Section IV. No racemization occurred at any stage of the synthesis. 

The active ester methodology, which is widely used in peptide chemistry, has found only limited application in depsipeptide synthesis. A more vigorous activation of the carboxy component is apparently required to form an ester bond compared to the peptide analogue. Nevertheless, active esters have been utilized for this purpose in combination with some catalyst additives. The first successful attempt in this direction was described by Mazur.1103 The modification of the 4-nitrophenyl ester procedure included addition of 1-10 equivalents of imidazole to the reaction mixture. This accelerated technique presumably involves formation of the highly reactive intermediate imidazolide. The reaction resulted in the preparation of model benzyloxycarbonyl didepsipeptide esters in good yields within several hours at room temperature from 4-nitrophenyl esters of Z-amino acids and the pentamethylbenzyl ester of glycolic acid, while in the absence of imidazole this reaction failed to give any product. 

In contrast to the syntheses described above, leading to zwitterionic complexes based on the (SiOztC) ligand framework, a direct synthesis of SiOs-based zwitterions has also been reported simultaneous reaction of one equivalent of 2-(dimethylamino)ethanol and two equivalents of glycolic acid or 2,2-diphenylglycolic acid with tetramethoxysilane afforded the zwitterionic bis-glycolatosilicates 71 and 72 (equation 16)30. 

Grinstaff succeeded in growing bio-dendrimers via divergent synthesis with branched AB2 monomers, which could be of future use in the clinical sector. Adducts of glycolic acid and lactic acid or derivatives of adipic acid are examples of the monomers used [72 a]. 

Another interesting example is the Du Pont chemoenzymatic synthesis of glycolic acid, CH2(OH)COOH, a compound used in skincare products and biopolymers. In this process (Figure 5.16), formaldehyde (methanal) and HCN are reacted, giving... 

Kim, S J. et al., Increased in vivo collagen synthesis and in vitro cell proliferative effect of glycolic acid, Dermatol. Surg., 24, 1054, 1998. 

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