ACTA UIVERSITATIS PALACKIAAE LMUCESIS FACULTAS RERUM ATURALIUM 2001 CEMICA 40 DERIVATIVES F PTALIC ACID AYDRIDE I. SYTESIS AD STUDIES F REACTI PTALIC ACID AYDRIDE Miloslav ejsek and Iveta Wiedermannová Department of rganic Chemistry, Palacký University, tř. Svobody 8, 771 46 lomouc, Czech Republic Received May 31, 2001 Accepted August 28, 2001 Abstract By reaction of phtalic acid anhydride with thiosemicarbazide or semicarbazide -thioureidophthalamic acid (Ia) and -ureidophthalamic acid (Ib) were prepared. By cyclization of -thioureidophthalamic acid (Ia) and -ureidophthalamic acid (Ib) o-(2-amino-1,3,4-thiadiazol-5-yl)benzoic acid (Va) and o-(2-amino-1,3,4-oxadiazol- 5-yl)benzoic acid (Vb) were prepared. Key words: -thioureidophthalamic acid (Ia), o-(2-amino-1,3,4-thiadiazol-5-yl)benzoic acid (Va), -ureidophthalamic acid (Ib), o-(2-amino-1,3,4-oxadiazol-5-yl) benzoic acid (Vb) Introduction The area of the reactions of phthalic acid anhydride with nitrogen basis is very large. To the well-known reactions of phthalic acid anhydride belongs e.g. reaction with ammonium 1, 2, urea 3, 4, thiourea 5, hydroxylamine 6, 7, methylamine 8, ethylamine 9, 10, 11, and aniline 12, 13, 14, 15. In the 1-acylated semicarbazides and 1-acylated thiosemicarbazides, the nucleophilic interaction inside semicarbazide and thiosemicarbazide chain, respectively, may originate in others five-membered heterocycles. In the most general way, the following scheme sums up these possibilities. 15
R 2 =, S R = R R 2 The preparation of 5-phenyl-2-amino-1,3,4-thiadiazole and 5-phenyl-2-amino-1,3,4- -oxadiazole, respectively, was described in many reactions. As the initial substance, 1-benzoylthiosemicarbazide and 1-benzoylsemicarbazide, respectively, is used. Their cyclization happens in the presence of various substances, e.g. conc. sulphuric acid, phosphoric acid, acylchloride, and hydroxides, respectively. In other cases, semicarbazide (thiosemicarbazide) itself was used as the initial substance, which then reacted with benzoylchloride. The preparation of 5-phenyl-2,3-dihydro-1,2,4-triazol-3-thion or 5-phenyl-2,3-dihydro-1,2,4-triazol-3-on, respectively, was also described in various reactions. The cyclization of 4-benzoylsemicarbazide or 4-benzoylthiosemicarbazide happens best in the presence of hydroxides. 2 C C =, S 16
The reactions of phtalic acid anhydride with semicarbazide or thiosemicarbazide, respectively, which would originate in heterocycles, are not yet described in the literature. The originated heterocycles would correspond to the following structures: Based on the knowledge mentioned above, it was a very catchy idea to find the conditions, under which the 1,2,4-triazoles, and 1,3,4-thiadiazoles or 1,3,4-oxadiazoles, respectively, could originate. Results and discussion As the initial substance phthalic acid anhydride, semicarbazide and thiosemicarbazide, were used. The direct melting in the laboratory temperature and in the presence of glacial acetic acid and formic acid leads to the nucleophilic addition of semicarbazide (thiosemicarbazide) to phthalic acid anhydride. The addition leads to the openning of the phtalanhydric cycle and formation of -thioureidophthalamic acid (Ia) and -ureidophthalamic acid (Ib). (See scheme 1) + 2 2 C 2 (Ia) = S (Ib) = CR 2 (IIa) = S (IIb) = R = -C 3, -C 2 5 2 (IVa) = S 2 2 (IIIa) = S 2 (IVb) = (IIIb) = 2 C (Va) = S (Vb) = Scheme 1 17
When boiled in polyphosphoric acid or acetic acid, respectively, -thioureidophthalamic acid gives phtalimide. The carboxylic functional group of these o-substituted benzoic acids may be transformed to the esteric one (IIa), (IIb), amidic (IIIa), (IIIb) or hydrazidic one (IVa), (IVb), without leading to interactions with o-substitutes. In the presence of acid, -thioureidophthalamic acid hydrazide (IVa) and -ureidophthalamic acid hydrazide (IVb) cyclize, originating in o-(2-amino-1,3,4-oxadiazol- -5-yl)benzoic acid (Vb) and o-(2-amino-1,3,4-thiadiazol-5-yl)benzoic acid (Va), respectively. The cyclization of the amides of these acides was not successful. The amides of these acides split into phtalic acid monohydrazide under the same conditions. These heterocycles (Va), (Vb), also originate by the reaction of -thioureidophthalamic acid (Ia) or -ureidophthalamic acid (Ib) in sodium hydroxide. This cyclization does not happen in sodium carbonate. Experimental The melting points were determined on a Boetius stage and are not corrected. The infrared spectra were measured using KBr disc technique and scanned on an ATI Unicam Genesis FTIR instrument. elementar analyses were performed with an EA Elementar Analyses (Fison Instrument). MR spectra were measured on a Bruker AM-360 spectrometer (360 Mz) in DMS-d 6, the chemical shifts δ are reported in ppm and coupling constants are in ertz. -thioureidophthalamic acid (Ia) A) Phthalic acid anhydride (I) (2.25 g, 15.2 mmol) was dissolved when heated in 15 ml of glacial acetic acid. The solution was then cooled to the laboratory temperature and the solution of 1.5 g (16.48 mmol) of thiosemicarbazide in 25 ml of glacial acetic acid was added thereto in small amounts, when stirred instantly. The crystals of -thioureidophthalamic acid (Ia) occured immediately. The crystals were left to stand for 24 hours at 5 C, then collected by suction, washed with 150 ml of water, 50 ml of ether and dried under IR-lamp. The yield of dried product is 93.2 %, m.p. = 204 205 C. For C 9 9 3 3 S (239.19) calculated: 45.19 % C, 3.79 %, 17.57 %, 13.41 % S found: 45.14 % C, 3.48 %, 17.25 %, 13.66 % S IR (KBr, cm 1 ): 3423, 3335, 3257, 1677, 1625, 1484, 1231, 805 B) 2.25g of phthalic acid anhydride (I) and 1.5 g of thiosemicarbazide were mixed in the melting pot. This mixture was mildly heated in the oil bath, up to the temperature of 140 145 C during 15 minutes. The originated melt had yellowish colour. The melt was recrystallized in the acetic acid. White needle shaped crystals 18
occured (Ia), they were collected by suction, washed with 50 ml of ether and dried under IR-lamp. The yield of dried product is 83.5 %. C) -thioureidophthalamic acid (Ia) was prepared in the presence of formic acid in the analogous way as in the presence of the acetic acid. The yield of dried product is 86.0 %. Methylester of the -thioureidophthalamic acid (IIa) -thioureidophthalamic acid (Ia) (0.26g, 1.09 mmol) was heated when dissolved in 20 ml of the 3% solution of anhydrous hydrogen chloride in absolute methanol. This solution was refluxed for 5 hours. After cooling to the laboratory temperature, the methanol was evaporized. n the bottom of the flask, the yellow oil was left, and it was neutralized with ac 3 to p 7. White crystals, together with the oil fraction, started to separate. After several times recrystalization in methanol, the white crystalic substance was isolated. The pure ester could be very hard isolated, therefore, for the next reactions, the crude ester was used. The yield of dried product is 90.0 %, m.p. = 59 61 C. For C 10 11 3 3 S (253.21) calculated: 47.43 % C, 4.38 %, 16.60 %, 12.64 % S found: 47.23 % C, 4.11 %, 16.33 %, 12.70 % S Ethylester of the -thioureidophthalamic acid (IIa) Ethylester of the -thioureidophthalamic acid (IIa) was prepared analogously as methylester of the -thioureidophthalamic acid (IIa), when -thioureidophthalamic acid (Ia) (260 mg, 1.09 mmol) and 20 ml of the 3% solution of anhydrous hydrogen chloride in absolute ethanol were used. For the next reaction, also the crude ester was used. The yield of dried product is 90.0 %, m.p. = 55 57 C. For C 11 14 3 4 S (267.24) calculated: 49.43 % C, 4.90 %, 15.73 %, 11.97 % S found: 49.20 % C, 4.65 %, 15.64 %, 11.55 % S Amide of -thioureidophthalamic acid (IIIa) Methylester of -thioureidophthalamic acid (IIa) (700 mg, 2.75mmol) was spilled with 5 ml of 23% ammonium, under instant stirring and cooling to 5 C. The solution was stirred half an hour in ice bath. It was left to stand for 24 hours in 5 C and yellowish crystals separated, which were then recrystalized in ethanol. After recrystalization, white needle shaped crystals separated. In an analogous way, the amide was prepared from ethylester of -thioureidophthalamic acid (IIa). The yield of dried product is 82.0 %, m.p. = 124 126 C. For C 9 10 4 2 S (220.20) calculated: 45.28 % C, 4.23 %, 23.52 %, 13.43 % S found: 45.45 % C, 4.15 %, 23.04 %, 13.00 % S IR (KBr, cm 1 ): 3459, 3367, 3262, 3179, 1645, 1624, 1533, 801 19
ydrazide of -thioureidophthalamic acid (IVa) Crude methylester of -thioureidophthalamic acid (IIa) (700 mg, 2.75 mmol) was spilled with 8ml of 30% hydrazine under instant stirring and cooling to 5 C. The solution was stirred in ice bah for 30 minutes, then left to stand for 24 hours at 5 C. White crystals separated and were recrystalized in ethanol. In an analogous way, hydrazide from the ester of -thioureidophthalamic acid (IIIa) was prepared. The yield of dried product is 81.9 %, m.p. = 204 205 C. For C 9 11 5 2 S (253.22) calculated: 42.69 % C, 4.38 %, 27.67 %, 12.64 % S found: 42.45 % C, 4.36 %, 27.12 %, 12.72 % S IR (KBr, cm 1 ): 3415, 3277, 1631, 1573 o-(2-amino-1,3,4-thiadiazol-5-yl)benzoic acid (Va) A) ydrazide of -thioureidophthalamic acid (IVa) (204 mg, 0.99 mmol) was dissolved in the solution of 100 mg (2.5 mmol) a and 13 ml 2 under laboratory temperature. This solution was refluxed for 30 minutes. After cooling to the laboratory temperature, the solution was neutralized with diluted chloric acid to p 7. The solution was left to stand for 24 hours at 5 C. After this time, white crystals of o-(2--amino-1,3,4-thiadiazol-5-yl)benzoic acid (Va) separated. The yield of dried product is 89.3 %, m.p. = 269 270 C. For C 9 7 3 2 S (221.17) calculated: 48.87 % C, 3.19 %, 19.00 %, 14.46 % S found: 48.55 % C, 3.09 %, 19.53 %, 14.26 % S IR (KBr, cm 1 ): 3098, 1700, 1601, 1456, 1285, 1068, 974, 725 13 C MR spectra: 167.49, 166.24, 150.64, 132.28, 131.78, 130.77, 130.65, 130.09, 126.03 B) -thioureidophthalamic acid (Ia) (240 mg, 1.003 mmol) was dissolved in the solution of 100 mg (2.5 mmol) a in 30 ml 2. The solution was refluxed for 50 hours. After cooling to the laboratory temperature, the solution was neutralized with diluted chloric acid (1:1) to p 7. After standing for 24 hours at 5 C, the yellowish crystals of o-(2-amino-1,3,4-thiadiazol-5-yl) benzoic acid (VIIa) separated and they were recrystalized in ethanol. -ureidophthalamic acid (Ib) A) Phthalic acid anhydride (I) (2.25g, 15.2 mmol) was dissolved when heated in 15 ml of glacial acetic acid. The solution was cooled to the laboratory temperature and under instant stirring and in small amounts, the solution of semicarbazide hydrochloride (1.4g, 16.48 mmol) in 40 ml of glacial acetic acid with dissolved sodium acetate (1g, 12.19 mmol) was added. After condensation, white needle shaped crystals of -ureidophthalamic acid (Ib) separated. The crystals were collected by suction and washed with 50 ml of ether, then dried under IR-lamp. The yield of dried product is 79.4 %, m.p. = 194 196 C. 20
For C 9 9 3 4 (223.19) calculated: 48.43 % C, 4.06 %, 18.83 % found: 48.25 % C, 4.00 %, 18.23 % IR (KBr, cm 1 ): 3477, 3346, 3269, 3209, 1748, 1682, 1576, 1200 B) Phthalic acid anhydride (2.25 g, 15.2 mmol) (I) was mixed with semicarbazide hydrochloride (1.4 g, 16.48 mmol) in the flask and heated to 150 C for 20 minutes. The white melt originated, and it was recrystalized in glacial acetic acid. The white crystals separated from the solution. The yield of dried product is 83.5 %. Methylester of -ureidophthalamic acid (IIb) -ureidophthalamic acid (Ib) (260 mg, 1.16 mmol) was dissolved when heated in 3% solution of anhydrous hydrogen chloride in absolute methanol. The solution was refluxed for 5 hours. After cooling to the laboratory temperature, methanol was evaporized in the vacuum evaporator. n the bottom of the flask, the yellowish oil was left, which was then neutralized with ac 3 to p 7. White crystals separated and were recrystalized in methanol. The yield of dried product is 82.0 %, m.p. = 56 58 C. For C 9 11 3 4 (225.20) calculated: 48.00 % C, 4.92 %, 18.66 % found: 48.11 % C, 4.72 %, 18.25 % Ethylester of -ureidophthalamic acid (IIb) Ethylester of -ureidophthalamic acid (IIb) was prepared in an analogous way as methylester, when -ureidophthalamic acid (Ib) (260 mg, 1.14 mmol) and 20 ml of 3% solution of anhydrous hydrogen chloride in absolute ethanol were used. The yield of dried product is 85.4 %, m.p. = 55 57 C. For C 9 13 3 4 (227.22) calculated: 47.57 % C, 5.77 %, 18.49 % found: 47.20 % C, 5.47 %, 18.19 % Amide of -ureidophthalamic acid (IIIb) Methylester of -ureidophthalamic acid (700 mg, 3.14 mmol) was spilled with 5 ml of 26% ammonium under instant stirring and cooling to 5 C. The solution was stirred for half an hour in ice bath. It was left to stand for 24 hours at 5 C, then white crystals separated and were recrystalized in ethanol. The yield of dried product is 80.4 %, m.p. = 120 122 C. For C 9 10 4 3 (222.20) calculated: 48.65 % C, 4.54 %, 25.22 % found: 48.33 % C, 4.30 %, 25.00 % IR (KBr, cm 1 ): 3388, 3335, 3267, 3192, 1685, 1624, 1484 21
ydrazide of -ureidophthalamic acid (IVb) Crude methylester of -ureidophthalamic acid (IIb) (700 mg, 3.14 mmol) was spilled with 8 ml of 30% hydrazine under instant stirring and cooling to 5 C. The solution was then stirred for half an hour in ice bath. It was left to stand for 24 hours at 5 C. White crystals occured, and they were recrystalized in ethanol. The yield of dried product is 86.0 %, m.p. = 154 156 C. For C 9 11 5 3 (237.22) calculated: 45.57 % C, 4.67 %, 29.53 % found: 45.21 % C, 4.59 %, 29.14 % IR (KBr, cm 1 ): 3408, 3312, 1710, 1627, 1561 o-(2-amino-1,3,4-oxadiazol-5-yl)benzoic acid (Vb) A) ydrazide of -ureidophthalamic acid (IVb) (204 mg, 0.86 mmol) was dissolved in the solution of 100 mg (2.5 mmol) a and 13 ml 2 under laboratory temperature. The solution was refluxed for 30 minutes. After cooling to the laboratory temperature, the solution was neutralized with diluted chloric acid to p 7. It was left to stand for 24 hours at 5 C and white crystals then occured. The yield of dried product is 90.5 %, m.p. = 258 260 C. For C 9 7 3 3 (205.17) calculated: 52.68 % C, 3.44 %, 20.48 % found: 52.44 % C, 3.37 %, 20.11 % IR (KBr, cm 1 ): 3335, 3192, 1654, 1629, 1268 13 C MR spectra: 167.45, 150.61, 132.23, 131.79, 130.66, 130.07, 126.03 B) -ureidophthalamic acid (Ib) (260 mg, 1.16 mmol) was dissolved in solution of 100 mg (2.5 mmol) a and 20 ml 2. The solution was refluxed for 48 hours. After cooling to the laboratory temperature, the solution was neutralized with diluted chloric acid (1:1) to p 7. It was left to stand for 24 hours at 5 C, then the white crystals of o-(2-amino-1,3,4-oxadiazol-5-yl)benzoic acid (Vb) separated Acknowledgment This research was supported by grant o. CEZ: J 14/98:7 000 000 8 of Grant agency of the Czech Republic and by grant o. MSM 15 31 0000 8 of MŠMT ČR. References 1. Kuhata, A.: Am. Chem. J. 3, 29 (1881). 2. oyes, K., Coss, A.: J. Am. Chem. Soc. 42, 1282 (1920). 3. Dunlap, E.: Am. Chem. J. 18, 333, (1896). 4. Grimaux, C.: Bull. Soc. Chim. Fr. 25, 241 (1876). 22
5. Piutti, M.: Justus Liebigs Ann. Chem. 24, 214 (1882). 6. Lach, F.: Chem Ber. 16, 1781 (1883). 7. Khadilkar, B. M., Samant, S. D.: Indian J. Chem. Sect. B. 11, 1137 (1993). 8. Spring, J., Woods, A.: J. Chem. Soc. 32, 624 (1945). 9. Wanag, C.: Acta Latviens Chem. 4, 405 (1938). 10. Sachs,.: Chem. Ber. 31, 1228 (1898). 11. Michael, M.: Chem. Ber. 10, 1645 (1877). 12. olik, M., Matějková, B.: Collect. Czech. Chem. Commun. 55, 261 (1990). 13. Auschuetz, K.: Chem. Ber. 20, 3215 (1887). 14. Piutti, M.: Chem. Ber. 36, 997 (1903). 15. Meyer, R., Sundmacher,.: Chem. Ber. 32, 2123 (1899). Acta Univ. Palacki. lomuc. Fac. rer. nat. (2001) Chemica 40, 15 23 23
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