Acetyl-H acid

A detailed comparison [181] of three vinylsulphone dyes included a low-substantivity monoazo N-acetyl H acid derivative (Cl Reactive Red 35), a monoazo N-acetyl J acid type of higher substantivity (Cl Reactive Orange 82) and a phthalocyanine turquoise somewhat prone to aggregation (Cl Reactive Blue 21). Dyeings of these individual products were subjected to three wash-off procedures ... 

Bluish red reactive dyes are almost totally dominated by H acid as the indispensable coupling component. Various mono- or disulphonated anilines or naphthylamines are suitable diazo components, but the outstandingly important one is orthanilic acid (7.96). As with orange and scarlet dyes, haloheterocyclic (Z) reactive systems are linked via the imino group of the H acid residue but sulphatoethylsulphone substituents are found in the diazo component with N-acetyl H acid as the typical coupler. A characteristic problem associated with reactive dyes derived from H acid is their accelerated fading under the simultaneous influence of perspiration and light (section 3.3.4). 

The use of pyridine during final coupling (pyridine coupling) is illustrated in the following abridged manufacturing specification for C. I. Direct Green 33, 34270 2-aminonaphthalene-8-sulfonic acid —> 3,5-xylidine- 2-ethoxy Cleve acid-6— A-acetyl H acid... 

Aniline (9.3 grams, 0.1 mole) is diazotized as described on page 259, and the diazo solution is mixed with the ice-cold soda solution of acetyl-H acid. The dye is salted out in the cold after 12 hours (20 per cent salt, calculated on the volume of the reaction mixture), filtered off, pressed in a screw press, and dried at 50°. The yield is about 50 grams. 

Acetamino-8-naphthol-3,6-disulfonic acid (acetyl-H acid)... 263... 

Chloro-2-aminophenol is used chiefly for the preparation of blue azo dyes which can be after-chromed. Its combinations with chromotropic acid and with acetyl-H acid were the purest chrome blues known before the discovery of the chroming triphenylmethane dyes (eriochrome azurol). The latter dyes are superior in depth and brilliance of color, but are not as fast to light as the azo dyes from 4-chloro.2-aminophenol and chromotropic acid or acetyl-H acid. 

For 3-acetylthiotetronic acid the same type of tautomerization process (90 91, 92 93 as a result of prototropy between internal tautomers 90, 91 92, 93, rotation of the side-chain group, between external tautomers) was observed as for the corresponding 3-acetyl-tetronic acids ( H NMR, NMR) [76JHC533 78BCJ651 79JCS (P2)1605],... 

Bommarius, A.S., Drauz, K., Klenk, H. and Wandrey, C. (1992) Operational stability of enzymes - acylase catalyzed resolution of /V-acetyl amino acids to enantiomerically pure L-amino acids. Annals of the New York Academy of Sciences, 672, 126-136. 

Yu, Y-R and Wu, W-H., Simultaneous analysis of enantiomeric composition of amino acids and A -acetyl-amino acids by enantioselective chromatography. Chirality, 13, 231, 2001. 

Kim, S. H., Choi, J. H., Park, H. S., et al. (2005) Association of thromboxane A receptor gene polymorphism with the phenotype of acetyl salicyhc acid-intolerant asthma. Clin. Exp. Allergy. 35, 585-590. 

N-Acetyl-4-O-acetylneuraminic acid Neu4,5Acj acetyl acetyl H H H... 

N-AcetyI-8-O-acetylneuraminic acid Neu5,8Ac2 H acetyl H acetyl H... 

V-Acetyl-9-O-acetyIneuraminic acid Neu5,9Ac2 H acetyl H H acetyl... 

N-Acetyl-9-O-phosphononeuraminic acid Neu5Ac9P H acetyl H H phosphate... 

O-AcetyI-iV-glycolylneuraminic acid Neu7Ac5Gc H glvcolvl acetyl H H... 

Di-0-acetyl-.V-glycolylneuraminic acid Neu7,9Ac25Gc H glycolyl acetyl H acetyl... 

H. S. Conradt, A. Biinsch, and R. Brossmer, Preparation of 9-fluoro-9-deoxy-Ai-[2-14C]acetyl-neuraminic acid, FEES Lett. 770 295 (1984). 

H. Ogura, K. Furuhata, S. Sato, and K. Anazawa, Synthesis of 9-O-acyl and 4-O-acetyl sialic acids, Carbohydr. Res. 167 11 (1987). 

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