1- Hydroxy-4-phenyl-5-carboxylic acid

After one day standing in a refrigerator, the product was filtered and washed with water, thus yielding 5 g of 2-phenyl-2-hydroxy-cyclohexane-carboxylic acid, melting point (Kofler) 143°C to 145°C. 

Thiophene-3-carboxylic acid, 4-hydroxy-5-phenyl-synthesis, 4, 927... 

Diketones 1 can be converted into the salt of an a-hydroxy carboxylic acid upon treatment with alkali hydroxide after acidic workup the free a-hydroxy carboxylic acid 2 is obtained. A well-known example is the rearrangement of benzil (R, R = phenyl) into benzilic acid (2-hydroxy-2,2-diphenyl acetic acid). The substituents should not bear hydrogens a to the carbonyl group, in order to avoid competitive reactions, e.g. the aldol reaction. 

Chemical Name 6-[ [ [ [(4-Hydroxy-1,5-naphthyridin-3-yl)carbonyl] amino] -phenyl acetyl] -amino] -3,3-dimethyl-7-oxo4-thia-1 -atabicydo[3.2.0] -heptane-2-carboxylic acid... 

Chemical Name 5,6,7,8-Tetrahydro-8-hydroxy-7-(hydroxymethyl)-5-(3,4,5-trimethoxy-phenyl)naphtho[2,3/1] -1,3-dioxole-6-carboxylic acid-2-athylhydrazide... 

Another class of hydrocarbon binders used in propints are the carboxy-terminated polybutadiene polymers which are cross-linked with either tris[l-(2-methyl)aziridinyl] phosphine oxide (MAPO) or combinations with phenyl bis [l -(2-methyl)aziridinyl] phosphine oxide (Phenyl MAPO). Phenyl MAPO is a difunctional counterpart of MAPO which makes possible chain extension of polymers with two carboxylic acid groups. A typical propint formulation with ballistic properties is in Table 11 (Ref 83) Another class of composites includes those using hydroxy-terminated polybutadienes cross-linked with toluene diisocyanate as binders. The following simplified equations illustrate typical reactions involved in binder formation... 

The carbocations generated by non-Kolbe electrolysis can rearrange by alkyl, phenyl or oxygen migration. The migratory aptitudes of different alkyl groups have been studied in the rearrangement of a-hydroxy carboxylic acids (Eq. 34) [323]. 

C12H10 92-52-4) see Bifonazole Fenbufen 4-biphenylacetonitrile (C14H11N J760i-77-7) see Felbinac [3aR-(3aa,4a,5p,6aa)]-[l,l -biphenyl]-4-carboxylic acid 4-formylhexahydro-2-oxo-2fl-cyclopenta[6]furan-5-yl ester (C2iH,80j 38754-71-1) see Latanoprost [3alt-[3aa,4a(l ,35 ),5p,6aa]]-[4,4 -biphenyl]-4-carb-oxylic acid hexahydro-4-(3-hydroxy-5-phenyl-l-pentenyl)-2-oxo-21/-cyclopenta[6]furan-5-yl ester (C3 H ,05 41639-73-0) see Latanoprost... 

The nitrilase from cyanobacterium Synechocystis sp. PCC6803 was found to effect the stereoselective hydrolysis of phenyl-substituted /3-hydroxy nitriles to (S)-enriched /3-hydroxy carboxylic acids. The enzyme also effected the conversion of y-hydroxynitrile, albeit with lesser enantioselectivity (Table 8.10). Interestingly, this enzyme was also was found to hydrolyze aliphatic dinitriles, such that for 1,2-dicyanoethane and 1,3-dicyanopropane the... 

More recently, some AMPA agonists showing unusual stereostructure-activity have been compared using the commercial docking package Glide (21). These include the enantiomers of 2-amino-3-(3-hydroxy-l,2,5-thiadiazol-4-yl)propionic acid (TDPA) and 2-amino-3-hydroxy-5-phenyl-4-isoxazolyl propionic acid (APPA) (28), as well as 3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-5-carboxylic acid (5-HPCA). 

There has been considerable interest in hydroxy-3,3 -bipyridines and 3,3 -bipyridinones. Following from some very early work on the oxidation of citrazinic acid (2,6-dihydroxypyridine-4-carboxylic acid), which was considered to give some polyhydroxy-3,3 -bipyridines, it has been shown that the 3,3 -bipyridinone 59, a product of the hydrolysis of a natural blue pigment from Corynehacterium insidiosum, is obtained by oxidation of 2-hydroxy-5-aminopyridine (60) or 2,6-dihydroxypyridine-4-carboxylic acid 61) 80,83 similar oxidation of 2,6-dihydroxy-3-aminopyridine-4-carboxylic acid affords the natural product indigoidine (20). Numerous related oxidative condensations have been reported subsequently. Cyano-acetamide condensations analogous to those discussed in the synthesis of 2,3 -bipyridines afford, for example, the cyano-substituted 3,3 -bipyridinone 62 588 v, lereas condensation of 3-pyridylacetonitrile with ethyl phenyl-propiolate and ethanol affords compound 63. To complete the section on... 

Ring transformation involving the intramolecular reaction of a hydrazone or in situ formed hydrazone also appeared. The transformation of 6-methyl-2//-pyran-2,3,4-trione 3-arylhydrazones 332 into l-aryl-6-methyl-4-oxo-l,4-dihydropyridazine-3-carboxylic acids 333 is an example of the former (Scheme 82). Compound 332 are formed via reaction of 4-hydroxy-6-methyl-27/-pyran-2-one 331 with substituted benzenediazonium chlorides. These are normally not isolated and immediately used further <2005EJM1325>. An example where a hydrazone is formed in situ is the reaction of 2-amino-5-aryldiazenyl-4-oxo-6-phenyl-4//-pyran-3-carbonitriles 334 with H2SO4 in glacial acetic acid, yielding 2-aryl-6-benzoyl-3-hydroxy-5-oxo-2,5-dihydropyridazine -carbonitriles 335 (Scheme 83) <2001T6787>. 

On irradiation of 86 (n = 2 and 3) in alcoholic solutions, methyl- (86%), ethyl- (74%), and isopropyl- (52%) esters of the corresponding j-(2-hydroxy-phenyl)-alkane carboxylic acids are formed.40,54 tert-Butanol, however, fails to yield any alcoholysis product whatsoever. A considerable influence of ring substituents on the quantum yield of ethanolysis of the lactones 86 and the... 

Coumestans,21 although they have a fused benzofuran ring, will be surveyed as being 8-lactones of 2-(2-hydroxyphenyl)-3-benzofuran carboxylic acids [coumestrol (4)22 is the 8-lactone of 2-(2,4-dihydroxy-phenyl)-6-hydroxy-3-benzofurancarboxylic acid]. The synthesis of some rotenoids 23 from benzofuran derivatives will also be reviewed, but dibenzofuran derivatives, such as usnic acid and its derivatives, will not be treated. 

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