Y- carboxylic acid

Formation of a six-membered ring by cyclization of a,y-carboxylic acid groups is also observed in the reaction of sulfur tetrafluoride with (1 / , S)-( + )-camphoric acid besides 1,2,2-trimethyl-3-(trifluoromethyl)cyclopentanecarbonyl fluoride (20) and camphoroyl difluoride (21). the bicyclic tetrafluoro ether, 2,2,4,4-tetrafluoro-l,8,8-trimethyl-3-oxabicyclo[3.2.1]octane (22). is formed. The ratio of products strongly depends on the reaction conditions.250... 

The relatively easy decarboxylation of a- (682) and y-carboxylic acids is a result of inductive stabilization of intermediate ylides of type (683) (cf. Section 3.2.1.8.2). By carrying out the decarboxylation in the presence of aldehydes or ketones, products of type (684) are formed (Hammick Reaction). 

The following unimportant preparative methods may be mentioned the production of /3-methyl anthraquinone by the reduction of 2-bromo-3-methyl anthraquinone 7 the oxidation of /3-methyl anthracene-y-carboxylic acid 8 and the reduction of 2-methyl anthraquinonyl-i-diazonium sulfate.9... 

DCCI, the modified polymers were found to contain considerable amounts of N-acy-lureic groups originating from side reactions between DCCI and the y-carboxylic acid functions. The formation of N-acylureic groups was completely suppressed when the modification reactions were carried out in the presence of one equivalent of hydroxy-benzotriazole.[21,22]... 

S)-(+)-Y-BUTYROLACTOHE-y-carboxylic acid (2-Furancarbo ylic acid, tetrahydro-5-oxo-, (S)-)... 

The (S)-(+)-y-butyrolactone-Y-carboxylic acid is a useful Intermediate for the synthesis of pheromones,4 natural lignans,5 and other derivatives.6 In the same manner, but starting with D-glutamic acid, the (R)-(-)-lactone acid may be prepared. Lactonization occurs with full retention of configuration at the chiral center.8 9 Recently, authors have described an efficient method which allows the formation of derivatives of the (R)-(-)-lactone from the more available (S)-(+) counterpart.10... 

Y-carboxylic acid (74) by approaches involving either acyl chlorides (oxalyl chloride route) or mixed carbonic anhydrides (isobutyl chloroformate route) (Scheme 120). An alternative route to (73) involves selective attack at the Y-carbonyl of anhydride (71) with diazomethane however the DON precursor (72) could not be prepared using this method. 

The deamination of L-glutamic acid (7-43) is useful because it leads to the pure (+)-(S)-y-butyrolactone-y-carboxylic acid (7.138, (5)-tetrahydro-5-oxofuran-2-car-... 

Pyroglutamic acid formation is a result of the condensation of either the amino group with y-carboxylic acid group of glutamic acids or the amino group with y-carboxamide group of glutamines at the A-terminal positions (Scheme 4.3-5) [27]. 

In the reactions of halo-y-carboxylic acid esters, e.g., BrCH2CH2CH2COOEt, decomposed products of the raw material were mainly obtained, as shown in Eq. (2.3) [19]. 

Perkin, J. Chem. Soc., 1868, 21, 56. Fittig, Brown, Ann., 1889, 255, 288. 1-Ethylcrotonic Acid (2-MethyU -ethyl-acrylic acid, amylene-y carboxylic acid)... 

Other reagents that open the epoxide ring with substitution, to give the useful derivatives indicated in parentheses, include phenols (phenyl ethers) (81) y carboxylic acids (esters) (8 ), hydrogen sulfide in the presence of barium hydroxide (thiols) (82), sodium methyl mercaptide (methyl thio-ethers) (83), dipotassium hydrogen phosphate or dibenzylphosphoric acid (phosphate esters) (84), alkyl or aryl magnesium halides (halodeoxysugars)... 

Butyrolactone-y-carboxylic acid refluxed 1 hr. with ethanol in benzene containing a little p-toluenesulfonic acid, then the resulting water removed by azeotropic distillation —ethyl butyrolactone-y-carboxylate. Y 95%.—Partial opening of the lactone ring occurs during esterification with ale. HCl. H. Plie-ninger et al., B. 94, 2106 (1961). 

The present report describes the covalent conjugation of paclitaxel to y-carboxylic acids of poly-L-glutamic (PG) acid (CT-2103). Paclitaxel is a particularly appropriate molecule for conjugation to a polymer carrier because it is broadly active as an anti-tumour agent, yet it is difficult to deliver because it is highly hydrophobic. The commercial preparations of pacKtaxel use Cremophor and ethanol as solubilising agents. These have inherent toxicities and require slow infusions and premedications with corticosteroids and histamine receptor blockers. 

The dicarboxylic acids found in basin brines (i.e., oxalic, malonic, and succinic) are expected to be less stable under hydrothermal conditions than monocarboxylic acids of comparable chain lengths. The stability of these acids has been discussed previously to the extent that structural factors make a-, and y-carboxyl acids susceptible to homogeneous decarboxylation. The mechanisms for decarboxylation of jff-carboxyl acids and their derivatives in solvents of varying polarity have been especially well studied and the results are believed to be generally applicable to a- and y-carboxyl acids as well (Clark 1969). For this reason, the following detailed discussion of the mechanism for homogeneous decarboxylation of dicarboxylic acids is based primarily on malonic acid. Finally, oxidation of dicarboxylic acids may be predicted, although the process has not been well studied. 

In actual fact this query results in two dihalogen derivatives of 2-methyl-quinoline-3,4-dicarboxylic acid. It is therefore clear that C-halogenated derivatives of free X-carboxymethyl-quinoline-Y-carboxylic acids are not present in the data base. This search technique is independent of the vagaries of chemical nomenclature the use of alternative names based on X-carboxy-quinol-Y-yl-acetic acids (etc.) is avoided. 

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