Aminobenzoate esters

Makino et al.35 developed a solid-phase synthesis of 1,3-disubstituted 2-thioxoquinazoline-4-ones using HMP Lanterns that were derivatized with a 4-aminobenzoate ester. Following the assembly of amide 25 (Scheme 9), SnAt reaction with alkyl amines gave support-bound products 26 with high conversion. The key thiocarbonylation step was achieved with thiocarbo-nyldiimidazole in decalin at 95° for 16 h in the presence of DMAP to afford 1,3-disubstituted 2-thioxoquinazoline-4-ones 27. The target compounds 28... 

Lupinine-Cytisine Group.—An X-ray analysis of (-)-lupinine hydrochloride and of (+)-epilupinine shows that bond lengths and angles are similar to those of lupinine (cf. Vol. 10, p. 68).16 Aminobenzoate esters of lupinine were prepared by transesterification reactions.17... 

Chemical Name 1-Propanol, 3-(dibutylamino)-, p-aminobenzoate (ester) Common Name Butacaine Butaprobenz Butocaina Chemical Abstracts Registry No. 149-16-6... 

It is possible to determine C quantitatively using Hildebrand s theory of microsolutes. An example of the accuracy that can be achieved is provided by the calculation of the solubilities of a series of p-aminobenzoate esters in hexane (17,18). Michaels, et al. (19) used this approach to estimate the solubility of steroids in various polymers. The solubilities of seven steroids in six polymers were calculated from the steroid melting points, heats of fusion, and solubility parameters. Equation 8 was derived, where Jjj is the maximum steady state flux, h is the membrane thickness, x is the product of V, the molar volume of the liquid drug, and the square of the difference in the solubility parameters of the drug and polymer, p is the steroid density, T is melting point (°K), T is the temperature of the environment, R is the gas constant, and AH and ASf are the enthalpy and entropy of fusion, respectively. 

Several laboratories have measured solubilities and/or partition coefficients of solutes in higher molecular weight media, and their data provides a test of this approach to estimating polymer solubilities. Flynn and Yalkowsky (17,18) studied the transport and solubility properties of a series of p-aminobenzoate esters, p-HjNCjH COOR, R = methyl to hexyl, in poly(dimethylsiloxane) fluid (PDMS). We find that their values of log P(PDMS) correlate well with reported (33) values of log P values of the same series of solutes in oleyl alcohol/water, as illustrated by the plot in Figure 8 and the correlation statistics (Equation 17). 

Figure 8. Correlation of log P of the solvent pairs silicone oil-water and oleyl alcohol-water for the series of aminobenzoate esters, p-NH2-C H4COO(CHJ H. Numbers at each data point refer to n, the ester chain length. Data from Refs. 17 and 18.

Aldehydes, introduction in polysaccharides, 189-190 Aligned fiber moderators, flow rate, 346r Amine functions, effect on pH sensitivity of poly(ortho esters), 176-178 Aminobenzoate esters, correlations of partition coefficients for solvent pairs, 62,63/... 

In contrast, allergic reactions to local anesthetics, although rare, are known to occur exclusively with p-aminobenzoic ester-type local anesthetics (18). Whether the formation of PABA on ester hydrolysis is solely responsible for this hypersensitivity remains to be investigated. However, the preservative compounds, such as methyparaben, used in the preparation of amide-type local anesthetics are metabolized to PABA-like substance, p-hydroxybenzoic acid. Thus, patients who are allergic to amino ester-type local anesthetics should be treated with a preservative-free amino amide-type local anesthetic. 

The C-N bond formation proceeded in high yields for aryl chlorides when treated with benzylamine or 3-aminobenzoic ester, reflecting the compatibihty of the ester group with KOH as a base. 

N -Aoetyl-N-anthranilylan-thranilic azlactone m-Aminobenzoic ester p-Aminobenzoic ester... 

The hydrolysis of 2-aminobenzoate esters in the range of pH 4 to 8.5 oeeurs by in-tramoleeular general base catalysis of the 2-amino group. The amine enhances the reactivity of the water by partially removing a proton as the water attacks the carbonyl group. 

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