Pentanoic acid, 288 Table

Using 4,4,-bis(4-hydroxyphenyl)pentanoic acid (BHPA)196 197 as comonomer, some polysulfones with pendent carboxylic groups were successfully synthesized.198199 Table 6.1 shows the structure of BHPA. The functional groups can be used for the preparation of graft copolymers. 

An independent proof of this finding was recently obtained by Ciardelli, Benedetti, Pieroni and Pino (23, 24) who prepared an atactic poly-(S)-4-xnethyl-1-hexene having [M] >5 = +190 from a poly-(S)-4-methyl-l-hexyne having an optical purity of about 89.5% as demonstrated by the optical purity of (S)-3-methyl-pentanoic acid obtained by ozonization of the unsaturated polymer. The rotatory power of the polymer thus prepared is very near to the rotatory power of the non crystallizable poly-(S)-4-methyl-l-hexene obtained from a monomer having a 93% optical purity (see Table 8). 

The hydrolysis of lactams is rather stndghtforward and most of the variety in this table results from different structural features and different synthetic manipulations of the lactams. Reaction I shows a simple hydroly of 3-methyl-2-pyrrolidinone 2.48) to give 2-ethyl-4-aminobutanoic acid 2.49). Several substituted derivatives were prepared, including 2-methyl-4-aminobutanoic acid, 3-ethyl-4 aminobutanoic acid, 3-propyl-4-aminobutanoic acid, 3-(l-methylethyl)-4-aminobutanoic acid, 2,3-diethyl-4-aminobutanoic acid, 2-ethyl-S-aminopentanoic acid, 3-methyl-5-amino-pentanoic acid, 3-ethyl-5-aminopentanoic acid, 3-propyl-5-aminopentanoic acid, and 3-( 1 -methylethyl)-5-aminopentanoic acid. l... 

The easiest way to control the content of 3HV units in the P(3HB-co-3HV) copolymer is by changing the concentration of the carbon source which contributes to the formation of 3HV units. Doi and co-workers found that by using a combination of butyric and pentanoic acids, R. eutropha (NCIB 11599) can be made to produce P(3HB-co-3HV) copolymers containing a wide range (0-85 mol%) of 3HV units (Table 7.1). 

A disadvantage of this reaction is the statistical coupling of the intermediate radicals. This results in the additional formation of two symmetrical dimers as major side products. However, by taking the less costly acid in excess the number of products is lowered to two, the unsymmetrical product and one symmetrical dimer. When the chain length of the two acids is properly chosen, the two products can usually be separated by distillation. Furthermore, the more costly acid is incorporated to a major extent into the mixed dimer. The calculated yields for mixed couplings are listed in Table 4, and the experimental results for the coupling of methyl azelate with pentanoate are shown in Table 5." ... 

The addition of the 5-pentanoate radical from methyl adipate to butadiene has been intensively investigated, because in this way long chain l,n-diacids are easily accessible a total yield of 96% has been claimed for this reaction (Table 8, entry 7). Different Kolbe radicals from acetic acid, monochloroacetic acid, trichloroacetic acid, oxalic acid, methyl adipate and methyl glutarate have been added to ethylene, propylene, fluoroalkenes and dimethyl maleate. In this detailed study the influence of current density, alkene type and alkene concentration on the product yields and product ratios have been discussed. 

Also very different (7 )-2-hydroxy carboxylates could be dehydrogenated on a preparative scale. Scheme 4 summarises the unusually broad range of applications. With R)-2-hydroxy-3-enoiccarboxylates (43) we performed a series of reactions which led to highly fimctionalised acids with 3 chiral centres (44,45) (Table 13). The product of 22 (Table 10) was used to prepare various 5-methoxy-pentano-1,4-lactones (45). Tables 10, 11, 15 and 16 give an impression and suggestions for applications of Proteus species with other substrates. 

Figure 10. Two-dimensional space regenerated from weighting Lafforfs parameters shown in Table III in an attempt to reproduce the psychophysical space in Figure 8. Three acids, acidic, formic, and pentanoic, were not included because Laffort s parameters were not known for these stimuli (21),...

In order to determine the taste modulating activity of the identified compounds, triangle tests were performed with the purified compounds dissolved in water (for intrinsic taste) as well as in a model broth solution (for taste modulatory activity), respectively. None of the compounds 1-5 showed any intrinsic taste up to a maximum concentration of 1000 pmol/kg, but all these creatinine derivatives imparted taste modulating activity in model broth by enhancing its thick-sour, brothy taste. The lowest threshold concentration of 76 pmol/kg was found for 4-hydroxy-2-A-(l-methyl-4-oxoimidazolidin-2-ylideneamino) butanoic acid (3), whereas the highest threshold level of 489 pmol/kg was determined for 4-hydroxy-2-77-(l -methyl-4-oxoimidazolidin-2-ylideneamino)pentanoic lactone (4) (Table 1). 

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