rated t o a small volume and acidified to pH 4 using 0.1 N HCl.The precipitate thus formed was collected by centrifugation, washed several times with water, and dried in vacuo to give 30% yield of the product, 6, as a brown powder, mp >300'. In 0.1 N NaOH XmRX were found at 380 nm (e 10,117) and 275 (23,690), and in 0.1 N HC1 a t 346 and 271 nm; nmr 9.10 (s, one proton, Hl), 7.75 (d, two protons, J = 8 cps, HV,W), 7.48 (d, two protons, J = 8 cps, HI,,S,j, 4.62 (t, a proton of glutamic acid), and 2.65 ppm (c, four protons of glutamic acid). Hydrolysis of 6 by HC1 in glacial HOAc gave P-6-COOH, p-aminobenzoic acid, and glutamic acid. Compound 5 was prepared in the same manner using p-aminobenzoic acid as the nucleophile. The product whichelutedat0.43 M NaClshowed kmsx in 0.1 N NaOHat380nm (e 10,507) and 275 (22,809), and in 0.1 N HCl a t 350 and 275 nm. On acid hydrolysis 5 gave P-6-COOH and p-aminobenzoic acid.Synthesis of 9-Oxoisohomopterioc Acid (11). A. Preparation of a-Amino-p-toluic Acid.-p-Carboxybenzaldehyde (1.5 g) and 1.2 g of hydroxylamine hydrochloride were dissolved in 20 ml of EtOH and brought to reflux; a clear solution was obtained. To this was added dropwise 1.7 g of NaOH dissolved in 7 ml of water, over a period of 0.5 hr. Water (0.5 ml) was then added to bring the suspension into solution. Refluxing was continued for an additional 15 min and the reaction mixture was poured into 100 ml of ice-cold 20% HC1. The precipitate was collected by filtration and recrystallized from ILIeOH: yield 1.1 g; mp 223-224'; nmr (DMSO) 7.9 (q, four protons, J = 7 cps, aromatic), 8.3(6, one proton), and 10.2 ppm (s, one proton, carboxyl).The above oxime (1 g) was dissolved in 100 ml of 95% EtOH, 100 mg of 5y0 Pd/C was added, and hydrogenation was carried out for 18 hr at 30 psi. Filtration and washing the residue with two 20-ml portions of hot glacial HOAc gave a solution which was evaporated t o dryness. The solid thus obtained was triturated with absolute EtOH and filtered, producing 850 mg of solid. This was crystallized from water to give the white crystalline a-amino-p-toluic acid: mp 294-295'; Xmsx 234 nm (H20); nmr (TFA) 4.15 (9, J = 6 cps), 7.3 (d, J = 8 cps, two protons adjacent to the aminomethyl group), and 7.9 ppm (d, J = 8 cps, two protons adjacent to the carboxyl group).Treatment of this material with diazomethane gave the corresponding methyl ester, whose high-resolution mass spectrum showed the molecular ion a t 164.0708 (calculated for CoHloNO1, 164.0711), again representing the loss of a hydrogen from the benzylic position.B. Synthesis of 9-Oxoisohomopteroic Acid (ll).-a-Aminop-toluic acid and 8 (1 mmol of each) were treated as usual. After deprotection and chromatography on DEAE cellulose C1-, 11 eluted as a single band at 0.22 M NaCl, and was recovered from the pooled peak in about 36% yield. The uv spectral data revealed kmn, at 370 nm (e 10,750) and 270 (25,240) and Amin a t 320 and 250 nm in 0.1 N NaOH; nmr 9.25 (s, one proton, Hl), 8.15 (d, two protons, J = 8 cps, Hv,v), 7.7 (d, two protons, ...
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