CHEMISTRY
L. F. TREFILOVA and I. Ya. POSTOVSKII
Submitted 1957-01-01 | RussiaRxiv: ru-195701.15466 | Translated from Russian

Abstract

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CHEMISTRY

L. F. TREFILOVA and I. Ya. POSTOVSKII

SOME DIPHENYL DERIVATIVES AND THEIR TUBERCULOSTATIC ACTIVITY

(Presented by Academician I. N. Nazarov, January 15, 1957)

It is known that unsubstituted aniline has tuberculostatic action in vitro at a concentration of \(2 \cdot 10^{-4}\) mol/l \((^1)\). Para-substituted anilines—4-aminophenol, 4-methoxyaniline, 4-ethoxyaniline, 4-propoxyaniline—show greater activity: their tuberculostatic action appears at concentrations of \(2 \cdot 10^{-4}\), \(1 \cdot 10^{-5}\), \(1.25 \cdot 10^{-6}\), \(6.25 \cdot 10^{-7}\) mol/l \((^2)\). A significantly more active compound than aniline proved to be 4-aminodiphenyl: it shows tuberculostatic action already at a concentration of \(1.25 \cdot 10^{-7}\) mol/l \((^4)\). Taking these observations into account, Ch. P. Ivanov and I. M. Panaiotov \((^5)\) synthesized 4-hydroxy-4-aminodiphenyl and its alkyl ethers for testing their tuberculostatic activity.

Among derivatives of aromatic amines, azomethines and thiourea derivatives may be of interest as tuberculostatic compounds. The tuberculostatic activity of azomethines had already been studied earlier by Erlenmeyer and co-workers \((^6)\) and by Bäuzer and co-authors \((^7)\). The fungicidal action of certain azomethines is also known \((^8)\). As for thiourea derivatives, they have more than once been the subject of investigations of their antitubercular and fungicidal properties \((^9)\).

In the course of our investigations on the synthesis of compounds with possible antitubercular action, starting from 4-aminodiphenyl and its para-alkoxy derivatives, we obtained a series of new diphenyl derivatives, in particular azomethines (Table 1) and \(N,N'\)-substituted thioureas (Table 2). In addition, azomethines—derivatives of 4-diphenylaldehyde—were obtained.

The azomethines (Table 1) were obtained in almost quantitative yield by heating, in alcoholic solution, equimolecular amounts of 4-aminodiphenyl and its \(n\)-alkoxy derivatives with various aromatic aldehydes (benzaldehydes 1–5, salicylic aldehyde 6–10, vanillin 11–15, para-acetylaminobenzaldehyde 16–20, cinnamic aldehyde 21–25, piperonal 26), and also with furfural 27–31 and 9-formylacridine 32. Azomethines from 4-diphenylaldehyde were synthesized by reaction of this aldehyde with aromatic amines (aniline 33, \(n\)-anisidine 34, sulfanilamide 35, 4-aminodiphenyl 36, and 4-amino-4-methoxydiphenyl 37). The azomethines obtained are yellowish or yellow crystalline substances that crystallize well from alcohol, acetone, and dioxane.

Derivatives of \(N\)-diphenyl-\(N'\)-phenylthiourea (Table 2) were obtained in good yield (80–96%) by heating, in alcoholic solution, equimolecular amounts of 4-aminodiphenyl and its \(n\)-alkoxy derivatives with various mustard oils (allyl mustard oil 1–5, \(n\)-methoxyphenyl mustard oil 6–10, \(n\)-ethoxyphenyl mustard oil 11–15, \(n\)-chlorophenyl mustard oil 16–20). The thioureas obtained are colorless crystalline substances crystallizing from alcohol.

Table 1

No. Compound Substituent (X) Empirical formula M.p., °C N, % found N, % calc.
1 X–C₆H₄–C₆H₄–N=CH–C₆H₅ H C₁₉H₁₅N 147–148¹⁰
2 X–C₆H₄–C₆H₄–N=CH–C₆H₅ HO C₁₉H₁₅ON 202–203¹¹
3 X–C₆H₄–C₆H₄–N=CH–C₆H₅ CH₃O C₂₀H₁₇ON 173–174 4.99 4.88
4 X–C₆H₄–C₆H₄–N=CH–C₆H₅ C₂H₅O C₂₁H₁₉ON 146–147 4.90 4.65
5 X–C₆H₄–C₆H₄–N=CH–C₆H₅ C₄H₉O C₂₃H₂₃ON 180–181 4.29 4.25
6 X–C₆H₄–C₆H₄–N=CH–C₆H₄–OH H C₁₉H₁₅ON 140–141 5.29 5.13
7 X–C₆H₄–C₆H₄–N=CH–C₆H₄–OH HO C₁₉H₁₅O₂N 210–212 4.85 4.84
8 X–C₆H₄–C₆H₄–N=CH–C₆H₄–OH CH₃O C₂₀H₁₇O₂N 193–194 4.65 4.62
9 X–C₆H₄–C₆H₄–N=CH–C₆H₄–OH C₂H₅O C₂₁H₁₉O₂N 185–186 4.64 4.41
10 X–C₆H₄–C₆H₄–N=CH–C₆H₄–OH C₄H₉O C₂₃H₂₃O₂N 175–176 4.17 4.06
11 X–C₆H₄–C₆H₄–N=CH–C₆H₃(OH)(OCH₃) H C₂₀H₁₇O₂N 185–186 4.82 4.62
12 X–C₆H₄–C₆H₄–N=CH–C₆H₃(OH)(OCH₃) HO C₂₀H₁₇O₃N 254–255 4.64 4.39
13 X–C₆H₄–C₆H₄–N=CH–C₆H₃(OH)(OCH₃) CH₃O C₂₁H₁₉O₃N 186–187 4.41 4.20
14 X–C₆H₄–C₆H₄–N=CH–C₆H₃(OH)(OCH₃) C₂H₅O C₂₂H₂₁O₃N 182–183 4.30 4.03
15 X–C₆H₄–C₆H₄–N=CH–C₆H₃(OH)(OCH₃) C₄H₉O C₂₄H₂₅O₃N 129–130 4.07 3.73
16 X–C₆H₄–C₆H₄–N=CH–C₆H₄–NHCOCH₃ H C₂₁H₁₈ON₂ 235–236 8.55 8.91
17 X–C₆H₄–C₆H₄–N=CH–C₆H₄–NHCOCH₃ HO C₂₁H₁₈O₂N₂ 244–246 8.66 8.84
18 X–C₆H₄–C₆H₄–N=CH–C₆H₄–NHCOCH₃ CH₃O C₂₂H₂₀O₂N₂ 263–264 8.34 8.13
19 X–C₆H₄–C₆H₄–N=CH–C₆H₄–NHCOCH₃ C₂H₅O C₂₃H₂₂O₂N₂ 273–279 8.06 7.82
20 X–C₆H₄–C₆H₄–N=CH–C₆H₄–NHCOCH₃ C₄H₉O C₂₅H₂₆O₂N₂ 244–245 7.44 7.25
21 X–C₆H₄–C₆H₄–N=CH–CH=CH–C₆H₅ H C₂₁H₁₇N 189–190 4.88 4.94
22 X–C₆H₄–C₆H₄–N=CH–CH=CH–C₆H₅ HO C₂₁H₁₇ON 210–211 4.71 4.68
23 X–C₆H₄–C₆H₄–N=CH–CH=CH–C₆H₅ CH₃O C₂₂H₁₉ON 190–191 4.63 4.47
24 X–C₆H₄–C₆H₄–N=CH–CH=CH–C₆H₅ C₂H₅O C₂₃H₂₁ON 181–182 4.54 4.28
25 X–C₆H₄–C₆H₄–N=CH–CH=CH–C₆H₅ C₄H₉O C₂₅H₂₅ON 175–176 4.08 3.94
26 C₆H₅–C₆H₄–N=CH–benzodioxolyl C₂₀H₁₅O₂N 144–145 4.82 4.65
27 X–C₆H₄–C₆H₄–N=CH–furyl H C₁₃H₁₃ON 106–107 5.70 5.66
28 X–C₆H₄–C₆H₄–N=CH–furyl HO C₁₇H₁₃O₂N 266–267 5.35 5.32
29 X–C₆H₄–C₆H₄–N=CH–furyl CH₃O C₁₈H₁₅O₂N 126–127 5.03 5.05
30 X–C₆H₄–C₆H₄–N=CH–furyl C₂H₅O C₁₉H₁₇O₂N 157–158 4.83 4.81
31 X–C₆H₄–C₆H₄–N=CH–furyl C₄H₉O C₂₁H₂₁O₂N 165–166 4.51 4.39
32 C₆H₅–C₆H₄–N=CH–[[unclear: fused N-containing aromatic ring]] C₂₆H₁₈N 205–206 7.98 7.82
33 C₆H₅–C₆H₄–CH=N–C₆H₅ C₁₉H₁₅N 150–151¹²
34 C₆H₅–C₆H₄–CH=N–C₆H₄–OCH₃ C₂₀H₁₇ON 181–182 5.07 4.88
35 C₆H₅–C₆H₄–CH=N–C₆H₄–SO₂NH₂ C₁₉H₁₆O₂N₂S 239–240 8.29 8.33
36 C₆H₅–C₆H₄–CH=N–C₆H₄–C₆H₅ C₂₅H₁₉N 245–246¹³
37 C₆H₅–C₆H₄–CH=N–C₆H₄–C₆H₄–OCH₃ C₂₆H₂₁ON 241–243 3.99 3.86

The melting points and the results of analysis of the azomethines are given in Table 1, and those of the thioureas in Table 2.

Azomethines described in the literature are 1¹⁰, 2¹¹, 33¹², 36¹³ (Table 1), and the thiourea derivatives are 6¹⁴, 11 and 16¹⁵ (Table 2). The remaining compounds presented here were obtained for the first time.

In testing the tuberculostatic action of the azomethines in vitro against the virulent strain K₁ (human type), compounds 1, 6, 11, 13, 32 (Table 1) completely inhibited bacterial growth at drug concentrations from \(1 \cdot 10^{-6}\) to \(1 \cdot 10^{-7}\); the other compounds were less active, or exhibited no tuberculostatic activity at all.

The thiourea derivatives (Table 2) showed no activity at concentrations greater than \(1 \cdot 10^{-4}\). Thus, thiourea derivatives with a diphenyl residue should be assigned to compounds weakly active with respect to the tubercle bacillus in vitro, although the corresponding phenyl compounds are distinguished by high activity.

Table 2

No. Compound Substituent (X) Empirical formula m.p., °C N, % found N, % calc.
1 X–diphenyl–NH–C(=S)–NHCH₂CH=CH₂ H C₁₆H₁₆N₂S 159–160 10.57 10.44
2 X–diphenyl–NH–C(=S)–NHCH₂CH=CH₂ HO C₁₆H₁₆ON₂S 237–238 10.01 9.85
3 X–diphenyl–NH–C(=S)–NHCH₂CH=CH₂ CH₃O C₁₇H₁₈ON₂S 177–178 9.20 9.39
4 X–diphenyl–NH–C(=S)–NHCH₂CH=CH₂ C₂H₅O C₁₈H₂₀ON₂S 169–170 8.94 8.97
5 X–diphenyl–NH–C(=S)–NHCH₂CH=CH₂ C₄H₉O C₂₀H₂₄ON₂S 169–170 8.38 8.23
6 X–diphenyl–NH–C(=S)–NH–C₆H₄–OCH₃ H C₂₀H₁₈ON₂S 193–194^(14)
7 X–diphenyl–NH–C(=S)–NH–C₆H₄–OCH₃ HO C₂₀H₁₈O₂N₂S 244–246 8.33 8.00
8 X–diphenyl–NH–C(=S)–NH–C₆H₄–OCH₃ CH₃O C₂₁H₂₀O₂N₂S 206–207 8.05 7.69
9 X–diphenyl–NH–C(=S)–NH–C₆H₄–OCH₃ C₂H₅O C₂₂H₂₂O₂N₂S 209–210 7.43 7.40
10 X–diphenyl–NH–C(=S)–NH–C₆H₄–OCH₃ C₄H₉O C₂₄H₂₆O₂N₂S 202–203 7.11 6.89
11 X–diphenyl–NH–C(=S)–NH–C₆H₄–OC₂H₅ H C₂₁H₂₀ON₂S 197–198^(15)
12 X–diphenyl–NH–C(=S)–NH–C₆H₄–OC₂H₅ HO C₂₁H₂₀O₂N₂S 243–245 7.79 7.69
13 X–diphenyl–NH–C(=S)–NH–C₆H₄–OC₂H₅ CH₃O C₂₂H₂₂O₂N₂S 210–212 7.50 7.40
14 X–diphenyl–NH–C(=S)–NH–C₆H₄–OC₂H₅ C₂H₅O C₂₃H₂₄O₂N₂S 211–212 7.14 7.14
15 X–diphenyl–NH–C(=S)–NH–C₆H₄–OC₂H₅ C₄H₉O C₂₅H₂₈O₂N₂S 204–205 6.78 6.66
16 X–diphenyl–NH–C(=S)–NH–C₆H₄–Cl H C₁₉H₁₅N₂SCl 202–203* 8.39 8.27
17 X–diphenyl–NH–C(=S)–NH–C₆H₄–Cl HO C₁₉H₁₆ON₂SCl 246–247 7.99 7.90
18 X–diphenyl–NH–C(=S)–NH–C₆H₄–Cl CH₃O C₂₀H₁₇ON₂SCl 215–216 7.78 7.60
19 X–diphenyl–NH–C(=S)–NH–C₆H₄–Cl C₂H₅O C₂₁H₁₉ON₂SCl 216–218 7.33 7.32
20 X–diphenyl–NH–C(=S)–NH–C₆H₄–Cl C₄H₉O C₂₂H₂₃ON₂SCl 205–207 6.86 6.82

* In (15) 195°.

It is interesting that azomethine, obtained from 4-diphenylaldehyde and aniline (33), has absolutely no effect on the growth of tubercle bacilli, whereas the isomeric azomethine, obtained from 4-aminodiphenyl and benzaldehyde (1), possesses high tuberculostatic activity, \(0.2 \cdot 10^{-6}\). Compounds 34, 35, 36, and 37 also proved inactive. This indicates that, in the manifestation of antitubercular action, the essential role is played not so much by the diphenyl residue as by 4-aminodiphenyl.

The toxicity of the most active azomethines 1, 6, 11, and 13 (Table 1) was tested on white mice. The indicated azomethines proved to be considerably less toxic than 4-aminodiphenyl; however, in experiments on mice infected with the virulent strain K₁, they did not show a therapeutic effect.*

The microbiological tests of the compounds described here and the experiments on white mice were carried out by Candidate of Medical Sciences E. I. Chertkova (Sverdlovsk Scientific-Research Tuberculosis Institute).

Experimental Part

1. Preparation of 2-oxy-3-methoxybenzylidene-4-aminodiphenyl (11, Table 1). To a hot solution of 1.69 g (0.01 mole) of 4-aminodiphenyl in 4 ml of alcohol was added a hot solution of 1.52 g (0.01 mole) of vanillin in 4 ml of alcohol. The mixture was heated on a water bath for half an hour. After 10 min the solution becomes orange and small crystals precipitate from it. After cooling, the azomethine was filtered off and dried, m.p. 184–186°. Yield 2.9 g (95.7% of theory). The product was recrystallized from alcohol—yellow needles, m.p. 185–186° (for analysis see Table 1).

2. Preparation of N-4-(4′-methoxydiphenyl)-N′-(ethoxyphenyl)thiourea (13, Table 2). To a hot solution of 0.4 g

* It is evidently of interest to carry out further testing of the physiological action of the azomethines presented here, in particular their carcinogenic properties, if one takes into account that 4-aminodiphenyl shows a clearly carcinogenic action (16). The possibility is not excluded of finding among the azomethines of diphenyl carcinostatic substances as well, especially since one of the azomethines of the fluorene series, related to the carcinogenic derivative of fluorene, showed anticancer action (17).

A solution of 0.36 g (0.002 mole) of p-ethoxyphenyl isocyanate in 3 ml of alcohol was added to 0.46 g (0.002 mole) of 4-methoxy-4-aminodiphenyl in 10 ml of alcohol. The mixture was heated on a water bath for 15 min; the small colorless crystals that precipitated after cooling were filtered off and dried, m.p. 210–212°. Yield 0.7 g (92% of theory). After recrystallization from alcohol, m.p. 211–212° (for analysis see Table 2).

Ural Polytechnic Institute
named after S. M. Kirov

Received
4 I 1957

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Submission history

CHEMISTRY