Aminobenzoyl acetic acid

Quinoline and Furoquinoline Alkaloids (Fig. 151). (Activated ) anthranilic acid reacts with (activated ) acetic acid to 2,4-dihydroxyquinoline. Probably 2-aminobenzoyl acetic acid, which is in a pH-dependent equilibrium with 2,4-dihydroxy quinoline, or an activated derivative of this compound is an intermediate. On the one hand 2,4-dihydroxy quinoline is transformed to echinorine. On the other hand it is a precursor of 3-prenylated chinoline alkaloids, isopropyl-dihydrofuroquinolines and furoquinolines. 

In a variant of the above approach, Temple et al. [37c] converted (III. 129) successively to the dichloride (III.134) (72%) and the 2-amino-4(377)-oxo derivative (III.135) (75%). Treatment of (III.135) with acetic anhydride and sulphuric acid followed directly by bromination at 95 °C in acetic acid in the presence of sodium acetate, condensation with 7V-(4-aminobenzoyl)-L-glutamic acid, and alkaline hydrolysis afforded a low yield of (III. 124), whose UV spectral properties (pH 1) 250 nm (e 15,100), 298 (19,400) ... 

There are four preparation methods for S-acyl sulfenamides 96 (1) RC(0)SX (X=Cl,Br,I)+R NH [20,284] (2) M(RCOS) (M=Na,K)+R NCl [78,229,262] (3) M(RCOS) (M=Na, K) + sodium hydroxylamine-0-sulfonate (see Scheme 13) [262] (4) addition reaction of RCOSH to activated N=N double bond [67]. The cyclic compounds 97, such as benzoisothiazolinones, have also been obtained by oxidizing the corresponding isothiazolthiones with KMn04 [198] or iso-propylethylenoxide [82] and by heating bis(o-aminobenzoyl) disulfide in acetic acid [64]. 

Reductone (HOCH=COH—CHO) has been condensed with ethyl N-(p-aminobenzoyl)glutamate to form ethyl iV-[/>-(2,3-dihydroxy-2-ene-propyl-idene-amino)-benzoyl]glutamate which can be condensed with 2,4,5-triami-no-6-hydroxypyrimidine to form folic acid . Another procedure for folic acid synthesis involves the alkylation of A -tosyl-/>-aminobenzoylglutamate with a substituted propylene oxide such as 2,3-oxidopropionaldehyde diethyl acetal, oxidation of the product to a ketone, condensation of the ketone derivative with 2,4,5-triamino-6-hydroxypyrimidine and finally removal of the tosyl group . Other three carbon unit reactants, such as condensed with />-aminobenzoyl glutamic acid to give useful intermediates for folic acid synthesis . 

A sirupy pentapropionate of L-sorbose was described by Hurd and Gordon.142 Crystalline esters of L-sorbose, such as the 1-benzoyl-,55 1-p-aminobenzoyl-148 and 1-tosyl-, 144,56 have also been synthesized. 1-p-Aminobenzoyl-L-sorbose was prepared as a possible substance for measuring the rate of glomerular filtration. It was synthesized by esterifying 2,3 4,6-diisopropylidene-L-sorbose with p-nitrobenzoyl chloride, with subsequent reduction of the nitrobenzoyl ester to 1-p-amino-benzoyl-2,3 4,6-diisopropylidene-L-sorbose. Removal of the isopropyli-dene groups by dilute acid hydrolysis furnished the desired product. 1-Tosyl-L-sorbose was independently prepared by two different methods. The first method,55 discussed on page 110, involves the oxidation of a properly substituted sorbitol derivative, while the latter method144 is similar to the one used for the preparation of the 1-p-aminobenzoyl derivative, namely esterification of 2,3 4,6-diisopropylidene-L-sorbose, followed by acid hydrolysis. This cyclic acetal has also been esterified to the crystalline l-mesyl-2,3 4,6-diisopropylidene-L-sorbofuranose by... 

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