Synthesis and  Identification (Oxazepine, Pyrazole, Isoxazole)  compounds from  2-Aminobenzimidazole

 

Shaimaa Adnan1*, Kasim Hassan2, Hassan Thamer3

1College of Education, University of Al-Qadisiya Iraq

2College of Science, University of Babylon Iraq

3College of Education for Women, University of Kufa  Iraq

*Corresponding Author E-mail: shema.adnan@yahoo.com

 

ABSTRACT:

This research involved heterocyclic compounds such as (oxazepine derivatives , pyrazol derivatives,isoxazole derivatives),  were prepared by reaction 2-aminobenzaldehyde with salicylaldehyde  to get azo compound   (5-((1H-benzo [d] imidazol -2-yl)diazenyl)-2-hydroxybenzaldehyde) (1)  ,which  react (in acid medium ) with 4-Bromoaniline to get 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(((4-bromophenyl) imino)methyl)phenol (2) , and react with 4-aminobenzoicacid to get  1-(4-((5-((1H-benzo [d]imidazol-2-yl)diazenyl)-2-hydroxybenzylidene)amino)phenyl) ethanone (3) (both shiff base) . in other side ,(1) react ( in base medium ) with 4-Bromoacetophenon to get 3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-1-(4-bromophenyl)prop-2-en-1-one (4) ,and react with 4-hydroxyacetophenone to get 3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (5) (both chalcone derivatives). (2) and (3) react with phthalic anhydride and malic anhydride to get  3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-4-(4-bromophenyl)-3,4-dihydrobenzo [e] [1,3]oxazepine-1,5-dione (6), 3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-4-(4-acetylphenyl)-3,4-dihydrobenzo[e] [1,3]oxazepine-1,5-dione (7)   , 2-(5 -((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxy phenyl) -3-(4-bromophenyl)-2,3-dihydro-1,3-oxazepine-4,7-dione (8)  , 2-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-3-(4-acetylphenyl)-2,3-dihydro-1,3-oxazepine-4,7-dione(9) .(oxazepine derivatives) (4) and (5) react with hydrazinhydrate to get 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(3-(4-bromophenyl)-4,5-dihydro-1H-pyrazol-5-yl)phenol (10) ,  4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(3-(4-hydroxyphenyl)-4,5-dihydro-1H-pyrazol-5-yl)phenol (11) , and react with phenylhydrazine to get 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(5-(4-bromophenyl)-1-phenyl-2,3-dihydro-1H-pyrazol-3-yl)phenol(12),4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(5-(4-hydroxyphenyl)-1-phenyl-2,3-dihydro-1H-pyrazol-3-yl)phenol (13) (pyrazol derivatives).

 

4and 5 react with  hydroxylaminehydrochloride to get 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(3-(4-bromophenyl)-2,5-dihydroisoxazol-5-yl)phenol (14), 4-((1H-benzo [d]imidazol-2-yl)diazenyl)-2-(3-(4-hydroxyphenyl)-2,5-dihydroisoxazol-5-yl)phenol (15) (isoxazole derivatives) .All this compounds characterized by means of FT- IR ,and some of the compounds by means  1H-NMR,and 13C-NMR and follow reaction by Rf - TLC and Measure ment melting point  .

 

KEYWORDS: 2-aminobenzoimidazole , pyrazol , isoxazole, chalcone, schiff base.

 

INTRODUCTION:

Hetero aromatic compounds impart considerable attention in the design of biologically active molecules and advanced organic materials(1-3).

 

 

The pyrazole ring is common in a number of biologically active molecules. More recently extensive studies have been focused on pyrazole derivatives for exhibiting analgesic, anti-inflammatory, anticonvulsant, antidepressant, antiulcer, antidiabetic,cytotoxic, antitubercular and antibacterial. Antidepressants and anticonvulsants are among the most widely utilized drugs for the treatment of CNS disorders. Considerable interest has been focused on the pyrazole structure, which has been known to possess a broad spectrum of biological activities (4-9).

Isoxazoles are one of the five membered categorised heterocycles having two different hetero atoms in their cyclic skeleton. In recent years there has been renewed interest in them due to their uses as pharmaceutical1 and pesticide (10-12).

 

Oxazepine derivative is used as an antibiotic, enzyme inhibitor, pharmacological interest, and has a biological activity. It is used in relief of the psychoneuroses characterized by anxiety and tension(13-15).

 

Azo ligands of heterocyclic compounds have received a special interest in biological fields, due to the use some of these compounds as biological stains. These compounds were under intese investigation and their activity as neoplastic and antibacterial agents worth extra attention (16-18).

 

EXPERIMENTAL:

Apparatus:

(FTIR) Spectra (4000-400cm-1)in KBr disk were recorded on a SHIMADZU FTIR-8400S fourier. transform. melting point were measured using Stuart, UK.

 

1HNMR and 13C-NMR were recorded on fourier transformation bruker spectrometer, operating at (400MHz) with (DMSO-ds) measurements were made at Department of Chemistry, Kashan University. Iran.

 

General method of synthesis of azo compound (1) (19)

2-Amino-benzoimidazol (0.005 m.mole, 0.665gm) of the aromatic amine was dissolved in 5 ml of concentrated HCl and 8 ml of distilled water.The mixture is cooled to 0C0 and (0.005 m.mole, 0.345gm) of sodium nitrite to added drop wise with continuous stirring. The solution was left for 15 minutes to be stable after completing the addition (0.005 m.mole, 0.5 ml) of salicylaldehyde dissolved in( 1 gm NaOH in 50ml H2O) was added, a brown precipitate was formed, filtered and recrystallised from ethanol.

 

General method of synthesis of schiff bases (2,3)(20)

A mixture of equimolar quantities (0.01mol) of compound (1) and benzenamine derivatives was refluxed for 20 min in 20 mL of ethanol. The reaction mixture was cooled and kept for 24 h. The crystals found was filtered and dried.

 

General method of synthesis of Chalcone (4,5)(21)

chalcone was synthesized according to the hot condensation gms (0.1 mole) derivatives acetophenone and (0.1 mole) compound(1) were dissolved in minimum amount of ethanol, 55 ml of 50% potassium hydroxide was added to the above solution. The flask was heated at 50oC for twenty hours. The solution was acidified by cold 6 N HCl solution (congored), crystalline solid separated, which was filtered and washed with water. It was recrystallized from ethanol.

 

General method of synthesis of oxazepine (6,7,8,9) (22,23)

In a 100 ml round bottom flask equipped with double surface condenser fitted with calcium chloride guard tube was placed a mixture of 0.01 mole of shiffbase and 0.01mole (maleic anhydride, phthalicanhydride) in 20 ml of Ethanol absolute.The reaction mixture was refluxed in water bath at 78Cْ 3he, the solvent was then removed and the resulting solid was recrystallized from anhydrous THF.

 

General method of synthesis of pyrazol (10,11,12,13)(24)

In a 100 ml round bottom flask a mixture of 0.01 mole of Chalcone and 0.01mole (hydrazine hydrate, phenylhydrazine ) in 50 ml of Ethanol absolute. with continuous stirring at 72Cْ for 7 h, the solvent was then removed and the resulting solid was recrystallized from ethanol.

 

General method of synthesis of isoxazole (14,15) (25)

In a 100 ml round bottom flask a mixture of 0.001 mole of Chalcone and 0.001mole (hydroxylamine hydrochloride) in 50 ml of Ethanol absolute, after that add 0.025mole from ammoniumacetat with continuous stirring at 72Cْ for 7 h, the solvent was then removed and the resulting solid was recrystallized from ethanol.

 

RESULTS AND DISCUSSION:

Compound (1): 5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxybenzaldehyde

This compound was obtained as Brown solid yield 41. 6%, Rf =0.6, M.P (186)OC.

The infrared spectrum data of compound (1) show absorption at (1735) cm-1 for (C=O),(1458) cm-1 (-N=N-), (3409) cm-1 (OH) for phenol, and show band at (3139) for (N-H)for imidazol, and Disappearance band for NH2 at (3379-3325)cm-1

The1H-NMR (DMSO) spectrum data of compound (1) show δ:6.3-7.3(m, 7H, Ar-H), 7.65 (m, 1H, NH),8.21 (m, 1H,CH)Ald., 10.59 (m,1H, OH).

The13C-NMR (DMSO) spectrum data of compound (1) show δ:156.9 (C14), 138.3 (C11),132.09(C1), 131.27(C9), 130.59(C6,C7), 126.46(C13), 124.19(C3,C4), 123.95(C8), 121.40(C12),113.03 (C10), 110.14 (C2,C5).

 

Compound (2): 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(((4-bromophenyl) imino) methyl) phenol

Brown solid yield 80%, Rf =0.68, M.P(153)OC. The infrared spectrum data of compound (2) show absorption at (3016) cm-1 for (Ar-H),(3348) cm-1 (N-H),(594) cm-1 for(C-Br),(1626) cm-1 (C=N),and Disappearance band for (C=O) at (1735)cm-1.

 

Compound(3): 1-(4-((5-((1H-benzo[d]imidazol-2-yl) diazenyl)-2-hydroxybenzylidene) amino)phenyl)ethanone was obtained as brown solid yield52.7%,Rf =0.8,M.P (156)OC. The infrared spectrum data of compound (3)show absorption at (3031) cm-1 for (Ar-H),(3332) cm-1 (N-H),(1635)cm-1 (C=N),and show band at (1481) for (-N=N-),(3394) cm-1  for (O-H) and Disappearance band for (C=O) at (1735)cm-1.

 

 

Schem1: Preparation of compounds

 

 

Compound (4): 3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-1-(4-bromophenyl)prop-2-en-1-one as brown solid, yield 32%,Rf =0.65, M.P(197)OC.

The infrared spectrum data of compound (4)show absorption at,(3178) cm-1 (N-H),(1481)cm-1(N=N),and show band at(1735)cm-1for (C=O), and(3031) cm-1 for(C-H)for Ar-H, (594)cm-1 for (C-Br),(3363) cm-1 (OH) for phenol.

The1H-NMR(DMSO) spectrum data of compound (4) show δ:7.2-7.8(m, 11H, Ar-H), 7.3 (m, 1H, NH),6.8 (m,2H,HC=CH), 8.21.

 

Compound (5): 3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one brown solid, yield 58.8%,Rf =0.69, M.P(98d.)OC.

The infrared spectrum data of compound (5)show absorption at (1481)cm-1 for (N=N),(3124) cm-1 (N-H),(3031)cm-1(Ar-H),(1712) cm-1 for(C=O), and show band at (1218) for (C-O),(3363) cm-1 (OH) for phenol.

 

Compound (6): 3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-4-(4-bromophenyl)-3,4-dihydrobenzo[e][1,3]oxazepine-1,5-dione Brown-yellow solid, yield 85%,Rf =0.72, M.P(200)OC.

The infrared spectrum data of compound (6) show absorption at (3031) cm-1 for (Ar-H),(1630)cm-1(C=N),and show band at (1481) for (N=N),(594) cm-1  for (C-Br),(1700) cm-1  for (C=O).

 

Compound (7): 3-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-4-(4-acetylphenyl)-3,4-dihydrobenzo[e][1,3]oxazepine-1,5-dione as lightgolden solid, yield 91.5%,Rf =0.81, M.P(175)OC.

The infrared spectrum data of compound (7) show absorption at (3039) cm-1 for (Ar-H),(1674)cm-1(C=N),and show band at (1481) for (N=N),(1712) cm-1 for  (C=O).

The1H-NMR(DMSO) spectrum data of compound (7) show δ:6.8-8(m, 11H, Ar-H), 10.5 (s, 1H, NH),10.7 (m, 1H,OH),8.2(s,1H,CH-N),1.32 (m,3H, CH3) .

The13C-NMR(DMSO) spectrum data of compound (7) show δ:199 (C23), 170 (C15) 169.5(C16), 169(C11), 165.86(C17), 145.5(C1), 140.02(C20), 136.17(C6,C7), 133.49(C26),133.34 (C27), 132.03 (C29,C30), 131.71(C13,C12), 131.26(C19,C21), 131.21(C9,C28), 130.09 (C25), 129.39 (C3,C4),121.97(C18), 120.32(C8), 112.92(C16), 110.12(C2,C5).

 

Compound (8): 2-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-3-(4-bromophenyl)-2,3-dihydro-1,3-oxazepine-4,7-dione as purple solid, yield 75.8%, Rf =0.7, seram.

The infrared spectrum data of compound (8)show absorption at (1735)cm-1 for (C=O)oxazepin,(3132) cm-1 (N-H),(1650)cm-1(C=N),(3355) cm-1 for(OH), and show band at (594) for (C-Br) and show band at (1488) for (N=N).

The1H-NMR(DMSO) spectrum data of compound (8) show δ:6.07-7.49(m, 11H, Ar-H), 10.58 (s, 1H, OH),4.1-3.6 (m, 2H,CH=CH),8.4(s,1H,CH-N),7.57 (m,1H, N-H).

 

The13C-NMR(DMSO) spectrum data of compound (1) show δ:169 (C15), 165 (C18) 156.91(C11), 152.16(C1), 136.3(C19), 136.07(C20,C24), 133.44(C6,C7), 133.19 (C16), 132.96(C21,C23),132.22 (C13,C12), 131.23 (C9), 130.16(C4,C3), 124.59(C22), 123(C8), 122.02(C17), 112.93(C10),110.14(C14).

 

Compound(9): 2-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-hydroxyphenyl)-3-(4-acetylphenyl)-2,3-dihydro-1,3-oxazepine-4,7-dione as brown, yield 92.8%,Rf =0.8, M.P(184) CO.

The infrared spectrum data of compound (8)show absorption at (1674)cm-1 for (C=O)oxazepin,(3271) cm-1 (N-H),(1630)cm-1(C=N),(3494) cm-1 for(OH), and show band at (1496) for (N=N).

The1H-NMR(DMSO) spectrum data of compound (9) show δ:6-7.8(m,11H, Ar-H), 8.3 (s, 1H, NH),4-4.3(m,2HC=CH), 8.2(s,1H,CH-N),3.1 (m,6H, CH3), 10.7(m,1H,OH).

 

The13C-NMR(DMSO) spectrum data of compound (9) show δ:198.5 (C25), 169 (C15) 165.5(C18), 156.92(C11), 144.85(C19), 137.63(C1), 133.94(C22), 133.52(C6,C7), 132.34(C16,C17),132.11 (C9,C23,C21,C13), 131.22 (C12), 131.04(C3,C4), 122.02(C20,C24), 120.27(C10), 110.17 (C2,C5), 30.61 (C14),28.02(C26), 120.32(C8), 112.92(C16), 110.12(C2,C5).

 

Compound(10): 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(3-(4-bromophenyl)-4,5-dihydro-1H-pyrazol-5-yl)phenol as brown-yellow solid, yield 90%,Rf =0.77, M.P(268)OC.

The infrared spectrum data of compound (10) show absorption at (1689) cm-1 (C=N),and show new band at (3178) for (N-H), (1481) cm-1 for(N=N) and (3024) Cm-1 for (Ar-H),(594)Cm-1 for (C-Br), (3363) Cm-1 for (OH)phenol.

The1H-NMR(DMSO) spectrum data of compound (10) show δ:6.8-7.6(m, 11H, Ar-H), 7.6 (s, 1H, NH), 10.5(m,1H,OH), 3.3(m,2H,CH2),4.09(m,1H,CH).

 

Compound(11): 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(3-(4-hydroxyphenyl)-4,5-dihydro-1H-pyrazol-5-yl)phenol as golden solid, yield =69.5%,Rf =0.87, M.P(236)OC.

The infrared spectrum data of compound (11) show absorption at (1689) cm-1 (C=N),and show new band at (3132) for (N-H), (1481) cm-1 for(N=N) and (3024) Cm-1 for (Ar-H), (3443) Cm-1 for (OH)phenol.

 

 

Compound (12): 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(5-(4-bromophenyl)-1-phenyl -2,3-dihydro-1H-pyrazol-3-yl)phenol as Brown solid, yield =36.4%,Rf =0. 7, M.P(283)OC.

The infrared spectrum data of compound(12) show absorption,(3178) cm-1(N-H),(1481) cm-1 for(N=N),(3024) cm-1  for (Ar-H), (3363) cm-1 for (OH)

 

Compound (13): 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(5-(4-hydroxyphenyl)-1-phenyl-2,3-dihydro-1H-pyrazol-3-yl)phenolas Brown solid, yield =63.4%,Rf =0.8, M.P(242)OC.

The infrared spectrum data of compound(12) show absorption,(3178) cm-1(N-H),(1481) cm-1 for(N=N),(3024) cm-1  for (Ar-H), (3363) cm-1 for (OH) The1H-NMR(DMSO) spectrum data of compound (11) show δ:6.8-7.61(m, 16H, Ar-H), 7.8 (s, 1H, NH), 10.5(m,2H,OH), 3.36(m,2H,HC-CH).

 

Compound (14): 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(3-(4-bromophenyl)-2,5-dihydroisoxazol-5-yl)phenol as brown solid, yield =79.2%,Rf =0.79, seram.

The infrared spectrum data of compound (14) show absorption at (3024) cm-1 for (Ar-H),(3178) cm-1 (N-H),and show new band at (3533) cm-1  for OH,(594) cm-1  for C-Br.

 

 

Table(1):- Analytical and physical data of compounds.

No.

Molecular formula

    Color

M.P°C

Yield%

Rf

1

C14H10N4O2

(266. 25)

Brown

186

41.6

0.6

2

C20H14N5O Br

(420.26.219)

Brown

153

80

0.69

3

C22H17N5 O2

(383.403)

Brown

156

52.7

0.8

4

C22H15N4O2Br

(447.284)

Brown

197

32

0.65

5

C22H16N4O3

(384.387)

Brown

98 d.

58.8

0.59

6

C28H18N5O4Br

(568.378)

Brown-yellow

200

85

0.72

7

C30H21N5O5

(338.42)

Light golden

175

91.5

0.81

8

C24H16N5O4Br

(285.32)

purple

seram

75.8

0.7

9

C26H19N5O5

(481.460)

Brown

184

92.8

0.8

10

C22H17N6O

(460.065)

Brown-yellow

268

90

0.77

11

C22H18N6O2

(398.417)

golden

236

69.5

0.78

12

C28H21N6OBr

(537.410)

Brown

283

36.4

0.7

13

C28H22N6O2

(474.513)

Brown

242

63.4

0.8

14

C22H16N5O2Br

(462.299)

Brown

seram

79.2

0.79

15

C22H17N5O3

(399.402)

Brown

101

87

0.6

 

 

Compound (15): 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-(3-(4-hydroxyphenyl)-2,5-dihydroisoxazol-5-yl)phenol as Brown solid, yield =87%,Rf =0.6, M.P(101)OC.

The infrared spectrum data of compound (14) show absorption at (3024) cm-1 for (Ar-H),(3132) cm-1 (N-H),and show new band at (3533) cm-1  for OH.

The1H-NMR(DMSO) spectrum data of compound (15) show δ:6.8-7.4(m, 11H, Ar-H), 7.7 (s, 1H, NH), 10.5(m,1H,OH), 3.36(m,2H,HC-CH).

 

 

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Received on 28.02.2014         Modified on 12.03.2014

Accepted on 30.03.2014         © AJRC All right reserved

Asian J. Research Chem. 7(3):  March 2014; Page 251-255