Chapter-2. A comprehensive review on biological activities...

Chapter-2. A comprehensive review on biological activities of 2-azetidinone

derivatives

Synthesis, antimicrobial evaluation and QSAR studies of novel derivatives of

4-thiazolidinone/2-azetidinone

46

2. A comprehensive review on biological activities of 2-azetidinone derivatives

2.1. Introduction

The chemistry and biological study of heterocyclic compounds has been

interesting field for a long time due to medicinal and agricultural reasons. The number

of heterocyclic derivatives containing nitrogen and sulfur atom possess broad

spectrum of biological activities (Patel et al., 2010). Even more than 70 years after the

discovery of penicillin, β-lactam antibiotics remain as one of the most important

contributions of science to humanity. The β-lactam skeleton is the common structural

element of the widely used penicillins, cephalosporins, thienamycin, nocardicins,

aztreonam and carumonam (Jarrahpour et al., 2006). The 2-azetidinone derivatives

have been reported to possess a wide range of biological activities i.e. antimicrobial,

anticancer, antitubercular, anti-inflammatory, anticonvulsant, antidiabetic, antiviral,

cholesterol absorption inhibitor, tryptase and chymase inhibitor, vasopressin V1a

antagonists and fatty acid amide hydrolase.

2.2 Chemistry of 2-azetidinone

2-Azetidinone is commonly known as β-lactam. A β-lactam ring is a four-

membered lactam. It is named as such, because the nitrogen atom is attached to the β-

carbon relative to the carbonyl. The name lactam is given to cyclic amides. The

biological activity of β -lactam skeleton is generally believed to be associated with the

chemical reactivity of their β -lactam ring and on the substituents especially at

nitrogen of the 2-azetidinone ring. The oxo group is at 2nd

position i.e. 2-azetidinone.

Substituents may be varied at N-1, C-3 and C-4 position as shown in Figure -1.

NO

R1

R2

R3

Figure-1

2.3. Biological activities of 2-azetidinone

Pharmacological interventions of 2-azetidinones derivatives are voluminous

but this chapter covers the latest and most relevant ones.

2.3.1. Antimicrobial activity

Trivedi et al. synthesized a novel series of benzo[b]thiophene derivatives

containing β-lactam nucleus and tested its in vitro for their antimicrobial activity


derivatives



47

against E. coli, P. aeruginosa, Bacillus subtilis, S. aureus, M. luteus bacteria and T.

longifusus, C. albicans, M. canis, F. solani fungal strains by the agar well diffusion

method. The preliminary in vitro biological activities of the title compounds 2-(3-

(2,4-dichlorophenoxy)-2-(aryl)-4-oxoazetidin-1-yl)-5-(2-(5-chloro-3-methyl-1-

phenyl-1H-pyrazol-4-yl)vinyl)-6,7-dihydro-7,7-dimethylbenzo[b]thiophene-3-

carbonitriles revealed that compounds 1 and 2 exhibited significant antibacterial (B.

subtilis value 18.70 mm and 18.86 mm) and antifungal (C. albicans value 94 mm and

91 mm) activities. The structure–activity relationship (SAR) shows that substitution at

the 2-position (ortho) of the phenyl substituent enhanced the antibacterial action of the

compounds (Trivedi et al., 2012).

S

NN

N

Cl

N

O

Cl

O

Cl

Cl

S

NN

N

Cl

N

O

OH

O

Cl

Cl

1 2

A new series of N-[3-(10H-phenothiazin-1-yl)propyl]-4-(substituted phenyl)-

3-chloro-2-oxo-1-azetidinecarboxamide derivatives were synthesized by Sharma et al.

The antibacterial, antifungal and antitubercular activities of synthesized compounds

have been assayed in vitro against selected bacteria, B. subtilis, E. coli, S. aureus, K.

pneumoniae and fungi A. niger, A. flavus, F. oxisporium, C. albicans and M.

tuberculosis (H37Rv strain), respectively. Streptomycin and griseofulvin used as

standard for antibacterial and antifungal activity, respectively and for antitubercular

activity, isoniazid and rifampicin were taken as standards. Nitro derivative (3) showed

higher activity than chloro or bromo group containing compounds. Results are

presented in Table 1. On the basis of SAR, they concluded that the activity of

compounds depends on electron withdrawing nature of the substituted groups. The

sequence of the activity is as follows: NO2 > Cl > Br (Sharma et al., 2012).


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48

Table 1. Antibacterial and antifungal activities (minimum inhibition concentration,

μg/mL) of compound 3

Comp. Antibacterial activity Antifungal activity Antitubercular

activity

B.

subtilis

E.

coli

S.

aureus

K.

pneumoniae

A.

niger

A.

flavus

F.

oxisporium

C.

albicans

M. tuberculosis

(H37Rv)

3 3.25 3.25 3.75 3.25 12.50 13.50 12.25 14.50 2.50

The MIC values of standard streptomycin for all bacterial strain and griseofulvin for

all fungi strain were in the range of 1.25–3.25 and 6.25–12.5 μg/ml, respectively. MIC

values of standard isoniazid and rifampicin were in the range of 1.25–2.50 μg/ml for

M. tuberculosis (h37rv strain)

Patel et al. synthesized a series of 2-azetidinone derivatives and studied them

against Gram positive bacteria (B. subtillies and S. aureus) and Gram negative bacteria

(E. coli and S. typhi) at a concentration of 50μg/ml by agar cup method. The area of

inhibition of zone is measured in percentage. Among the synthesized derivatives,

compound 4 [3-chloro-4-(2-hydroxyphenyl)-1-(4-(naphthalen-2-yl)thiazol-2-

yl)azetidin-2-one] was the most active one. This compound is equipotent and more

potent against Gram positive bacteria B. subtillis (85 %) and S. aureus (70 %) and

Gram negative bacteria E. coli (70 %) and S. typhi (80 %) as compared to the standard

drug penicillin (Patel and Mehta, 2006).

N

O

HN

O

Cl

S

HN

NO2

N

SN

O

H

H

Cl

OH

3 4

Mulwad et al. synthesized a series of N-[coumarin-6-yl] spiro-indoloazetidin-

2-ones/thiazolidin-4-one derivatives and evaluated their antibacterial activity against

four bacterial strains viz S. aureus, B. subtilis, P. aeruginosa and E. coli by cup plate

method. Among the tested derivatives, 1-(3-chloro-2-oxo-4-(2-oxoindolin-3-

yl)azetidin-1-yl)-3-(4,7-dimethyl-2-oxo-2H-chromen-6-yl)urea (5) showed the

maximum activity against S. aureus (83%), B. subtilis (87 %), P. aeruginosa (87%)


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49

and E. coli (91%) as compared to standard drug norfloxacin. Rest of the compounds

showed moderate to good biological activity (Mulwad et al., 2008).

Shingade et al. synthesized a series of 3-chloro-1-{2-[4-

(chloroacetyl)piperazin-1-yl]ethyl}-4-arylazetidin-2-one derivatives and screened its

antimicrobial activity against the following bacterial strains: B. subtilis ATCC 6633,

S. epidermidis ATCC 12228, M. luteus ATCC 4698, S. aureus ATCC 25923, S.

hominis ATCC 27844, B. pumilus ATCC 14884, B. cereus ATCC 11778, P. vulgaris

ATCC 13315, P. mirabilis ATCC 49565, S. typhi ATCC 19430, K. pneumonia ATCC

13883, E. coli ATCC 25922, and P. aeruginosa ATCC 10145 and against the

following fungal strains: A. niger ATCC 9142, A. awamori ATCC 22342, C. albicans

ATCC 10231, A. alternate ATCC 66868, M. canis ATCC 11622, R. solani ATCC

76131, T. longiformis ATCC 22397, A. flavus ATCC 15517, F. solani ATCC 38136,

and T. viride ATCC 52440. The activity data revealed that the compound 6 having

electron releasing substitution at 4th

position of the phenyl ring exhibited good

antibacterial as well as antifungal activity as compared to the other derivatives (Table

2) (Shingade and Bari, 2013).

O

O

CH3

NH

CH3

NH

O

N

O

NH

O

Cl

N

O

OH

N

N

O

Cl

Cl

5 6

Table 2. Antibacterial activity (µg/ml) of most active compound (6)

Comp. B.

subtilis

S.

epidermidis

M.

luteus

S.

aureus

S.

hominis

B.

pumilus

B.

Cereus

6 9.37 9.37 9.37 9.37 9.37 9.37 9.37

Standard. 2.34 2.34 2.34 2.34 2.34 2.34 2.34

Comp. P.

vulgaris

P.

mirabilis

S.

typhi

K.

pneumonia

E.

coli

P.

aeruginosa

6 4.68 9.37 9.37 9.37 4.68 9.37

Standard. 2.34 2.34 2.34 2.34 2.34 2.34


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50

Myangar et al. synthesized a series of 2-[(4’-oxo-3’-chloro-2’-phenylazetidin-

1’-ylamino)-methyl]-3-[N-isonicotinamide-yl]-quinazolin-4-one clubbed with 2-

azetidinone and the minimal inhibition concentration (MIC) of synthesized

compounds was carried out by broth dilution method against bacterial strains such as

some Gram-positive bacteria S. aureus (MTCC 96), S. pyogenus (MTCC 442), B.

subtilis (MTCC441) and Gram-negative bacteria E. coli (MTCC 443), P. aeruginosa

(MTCC 1688), Kl. pneumoniae (MTCC109), S. typhi (MTCC 98), and fungal strain

such as C. albicans (MTCC 227), A. niger (MTCC 282), A. clavatus (MTCC 1323)

and antitubercular activity against Mycobacterium tuberculosis. From in vitro

antibacterial activity data (Table 3), it is confirmed that compounds containing strong

electron withdrawing, i.e. 7 (4-nitro) exhibited excellent antibacterial activities against

the tested Gram-positive microorganisms while compound 8 (4-chloro) exhibited

excellent antibacterial activities against tested Gram-negative strains. The evaluation

of the in vitro antifungal activity demonstrated that compounds 9 (2-chloro) and 10

(4-OCH3) displayed highest activity against the fungal strains tested. Results are

presented in Table 3 (Myangar et al., 2012)

N

N

OHN C

O

N

CH2

HN N

HC

ClO

NO2

N

N

OHN C

O

N

CH2

HN N

HC

ClO

Cl

7 8

N

N

OHN C

O

N

CH2

HN N

HC

ClO

Cl

N

N

OHN C

O

N

CH2

HN N

HC

ClO

OCH3

9 10

A number of N-substituted-2-methyl benzimidazole derivatives of 2-

azetidione were synthesized by Ansari et al. and tested for their antimicrobial

activities against Gram-positive (S. aureus, S. mutans and B. subtilis), Gram-negative

(E. coli, S. typhi and P. aeruginosa) bacteria and fungi (C. albicans, A. flavus and A.

niger). Compounds 11 and 12 exhibited appreciable activity against S. aureus (38

mm) and B. subtilis (28 mm) comparable to reference compound, ampicillin and


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51

nalidixic acid. Compound 11 is also most active compound against fungal strain

Candida albicans (26 mm) as compared to reference drug Amphotericin B (Ansari

and Lal, 2009).

Table 3. Minimal inhibition concentration (µg/ml) of (7-10)

Comp. Gram –ve Gram + ve Fungi Antitubercular activity

E.c. P.a. Kl.p S.t. S.a. S.p. B.s. C.A. A.N. A.C. M.

tuberculosis

(µg/ml)

%

Inhibition

7 150 150 200 200 100 125 100 500 >1000 >1000 50 99

8 50 100 100 100 500 500 250 250 1000 1000 62.5 99

9 250 250 100 500 500 500 500 200 200 250 500 98

10 500 500 62.5 500 125 200 250 200 250 200 259 98

Gentamycin 0.05 1 0.05 1 0.25 0.5 - - - - 40 98

Ampicillin 100 100 100 100 250 100 - - - - 0.20 99

Chloramphenicol 50 50 50 50 50 50 - - - - - -

Ciprofloxacin 25 25 25 25 50 50 - - - - - -

Norfloxacin 10 10 10 10 10 10 - - - - - -

Nystatin - - - - - - - 100 100 100 - -

Greseofulvin - - - - - - - 500 100 100 - -

Rifampicin - - - - - - - - - - 40 98

Isoniazid - - - - - - - - - - 0.20 99

A novel series of azetidinones and thaizolidinones were synthesized by

Meshram et al. and screened for their biological activities against the panel of nine

bacterial strains (E. coli (mixed), B. subtilis, Pseudomonas sp., S. aureus, P. vulageris,

Salmonella sp., E. coli (+ve strain), Rhodococci, B. stearothermopelus). It was

observed that within the synthesized derivatives, 3-chloro-1-(4-(4-(2-hydroxyphenyl)-

2,3,5,6-tetramethyl-1,7-diphenyl-1,2,7,7a-tetrahydro dipyrazolo-[3,4-b:4',3'-e]-

pyridine-8(4H,6H,8aH)-yl)-phenyl)-4-(3-nitrophenyl) azetidin-2-one (13) showed

good activity against all bacterial strains (Table 4) (Meshram et al., 2011).

N

NCH3

CONH N

O

H3C

Cl

N

NCH3

CONH N

O

H3CH2C

Cl

N

O

N+O

O-N

N N

N

N

OH

Cl

11 12 13


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52

Table 4. Biological activities of compound 13

Comp. Zone of inhibition in mm

E.C

(mix)

B.S Pseudomonas sp. S.A P. V Salmonella sp. E. coli (-ve) Rhodococci B.S

13 15 4 10 5 12 12 - 3 4.5

Nystatin 17 6 12 9 17 19.1 11 6 7.2

Ceric et al. developed a simple and efficient procedure for the stereoselective

synthesis of new azetidinone-isothiazolidinones. New compounds were tested in vitro

on a panel of selected Gram-positive (S. aureus, E. faecalis and S. pneumoniae) and

Gram-negative (E. coli, H. influenzae and M.catarrhalis) bacterial strains. Compound

14 (trans form), with two aromatic substituents, showed the best inhibitory activity

against S. pneumoniae (MIC 8 µg/mL) as compared to amoxicillin (MIC 4 µg/mL)

(Ceric et al., 2010).

Gilani et al. synthesized a series of novel thiazolidin-4-ones and azetidin-2-

ones and tested their in vitro antimicrobial activity against one Gram positive bacteria

S. aureus (ATCC-25923), three Gram-negative bacteria E. coli (ATCC-25922), P.

aeruginosa (ATCC-27853) and K. pneumoniae (ATCC-700603) and five fungi C.

albicans (ATCC- 2091), A niger (MTCC-281), A. flavus (MTCC-277), M. purpureus

(MTCC 369) and P. citrinum (NCIM-768). The investigation of antibacterial and

antifungal screening data revealed that all the tested compounds showed moderate to

good inhibition at 12.5–200 µg/mL in DMSO. It has been observed that azetidin- 2-

one derivatives are found to be more active than thiazolidin-4-ones derivatives against

all pathogenic bacterial and fungal strains by using serial plate dilution method as

compared to the reference drugs ofloxacin and ketoconazole for bacterial and fungal

activity, respectively. The compounds 15 and 16 showed comparatively good activity

against all the bacterial strains. The good activity is attributed to the presence of

pharmacologically active 2,4-dichlorophenyl (15) and phenoxy group (16) attached at

the fourth position of the β-lactam moiety. Compounds 17 and 18 showed

comparatively good activity against all the fungal strains. These compounds contain

biologically active acetyl (17) and 4-nitrophenyl (18) groups attached at the fourth

position of β-lactam ring, respectively (Table 5) (Gilani et al., 2012).

A series of 3-chloro-1-(aryl)-4-(2-(2-chloro-6-methylquinolin-3-yl)-5-

(pyridin-4-yl)-1,3,4 oxadiazol-3(2H)-yl)-4-ethyl-azetidin-2-ones have been


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53

synthesized by Desai et al. and were screened for its antibacterial activity against E.

coli, P. aeruginosa, S. aureus and S. pyogenes, while antifungal activity was

determined against C. albicans, A. niger and A. clavatus using ampicillin and

griseofulvin as standard drugs. Compounds 19 possessed excellent activity against all

the microorganisms tested except A. clavatus (Desai and Dodiya, 2012).

N

NS

COOBnPh

ClPht

O

O

HN

O

HNS

N

Cl

N

O

Cl Cl

Cl

HN

O

HNS

N

Cl

N

O

O

Cl

14 15 16

O

O

N

O

HN

O

N

SN

Cl

Cl

NH

O

NHS

N

Cl

N

O

N+

O

O-

Cl

17 18

Table 5. Antimicrobial activity of the compounds 15, 16, 17 and 18

Comp. Zone of inhibition in mm and MIC (minimum inhibitory concentration) in µg/mL

Bacterial strains Fungal strains

S.

aureus

E. coli P.

aeruginosa

K.

pneumoniae

C.

albicans

A.

niger

A.

flavus

M.

purpureus

P.

citrinum

15 22 (25) 22 (25) 22 (25) 28 (12.5) 20 (50) 15

(100)

13

(100)

18 (50) 19 (50)

16 24 (25) 27

(12.5)

29 (12.5) 30 (12.5) 8 (<200) 9

(<200)

8

(<200))

4 (<200) 7 (<200)

17 4

(<200)

9

(<200)

8 (<200) 7 (<200) 24 (25) 30

(12.5)

29

(12.5)

26 (12.5) 25 (25)

18 13

(100)

20 (50) 19 (50) 16 (50) 30 (12.5) 27

(12.5)

30

(12.5)

22 (25) 29 (12.5)

Ofloxacin 22 (25) 30

(12.5)

27 (12.5) 29 (12.5) - - - - -

Ketoconazole - - - - 30 (12.5) 28

(12.5)

25 (25) 30 (12.5) 24 (25)

A new class of 2-azetidinyl-4-quinazolinones was synthesized by Patel et al.

and evaluated for its antimicrobial activity against S. aureus, P. aeruginosa, B.

subtilis and E. coli strains. All these compounds were compared with control drug


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54

penicillin-G. Compound 20 was found to be highly effective against S. aureus

(66.67% potency) and B. subtilis (57.44% potency) while compound 21 was found to

be effective against P. aeruginosa (65.76 % potency) and E. coli (53.33 % potency)

(Patel and Patel, 2011).

N

O

O

NN

N NCl

Cl

Cl

CH N

N

N

NH

Cl

Cl

Br

O

OCl

Cl

CH N

N

N

NH

Cl

Cl

Br

O

OCl

H3CO

19 20 21

Shah et al. synthesized a series of spiro[azetidine-2,30-indole]-2’,4(1’H)-

diones and were screened for its in vitro antibacterial activity against Gram-positive S.

aureus (MTCC-96) and Gram-negative E. coli (MTCC-521) and P. aeruginosa

(MTCC-647) and antifungal activity against C. albicans (MTCC-183) and A. niger

(MTCC-343). The activity of each compound was compared with amoxicillin,

gentamycin and streptomycin were used as standard drugs for antibacterial activity

and fluconazole and itraconazole for antifungal activity. Compound 22 displayed

equipotent antibacterial and antifungal activity with MIC value of 6.25µg/ml against

all the tested microorganisms compared to standard drugs (Shah et al., 2011).

Sahoo et al. synthesized a series of 3-phenoxy-4-(substituted phenyl)-1-(3’-

bromo-4’-methoxy benzamide) azetidin-2-ones and screened for its in vitro

antibacterial and antifungal activity using disc diffusion method. The results revealed

that compound 23 possessed good antibacterial activities against S. aureus, E. coli, B.

subtilis and P. aeruginosa with zone of inhibition 22, 20, 23 and 24 mm respectively.

Compound 24 showed significant antifungal activities against A. niger and C. albicans

with zone of inhibition 19 and 12 mm respectively (Sahoo et al., 2010).

Parmar et al. (2011) synthesized a substituted 2-azitidinones and screened

their antibacterial activity against Gram-positive (B. subtillis and S. aureus), and

Gram-negative (E. coli and P. aeruginosa) bacterial strains. Compound 25 inhibited

the growth of tested microorganisms with the zone of inhibition in the range of 14-19

mm. Azetidinone analogues were synthesized and evaluated for their antimicrobial


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55

activity against bacterial strains B. subtilis, S. aureus, E. coli and P. aeruginosa and

fungal strain C. albicans by Bhat et al. Compound 26 with zones of inhibition 15, 20,

21, 14 and 11mm for B. subtilis, S. aureus, E. coli, P. aeruginosa and C. albicans

respectively was found to possess marvelous antimicrobial activity compared to

standard drugs (Bhat et al., 2007).

NH

NCl

O

O

Br

Br

NO2

CONH

Br

H3CO

N

OC6H5O

OH

OCH3

CONH

Br

H3CO

N

OC6H5O

22 23 24

NN

O

N CH

OCl

OH

OCH3

HN

H2C

CNH

O ClO

NO2

25 26

Samadhiya et al. synthesized N1-3-{(4-substituted aryl-3-chloro-2-oxo-

azetidine)-iminocarbamyl} -propyl-6-nitroindazoles and screened their antimicrobial

activity against bacterial strains- B. subtilis, E. coli, S. aureus and K. pneumoniae and

fungal strains- A. niger, A. flavus, F. oxisporium and C. albicans using streptomycin

(antibacterial) griseofulvin (antifungal) as standard drugs. It was found that

compounds 27 and 28 displayed high activity against all the tested microorganisms

(Table 6) (Samadhiya et al., 2011).

O2N NN

CH2CH2CH2NH CO

N CH

ClO

NO2

NN

CH2CH2CH2NH CO

N CH

ClO

NO2

NO2

27 28


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56

Table 6. Antimicrobial activity of the compound 27 and 28

Comp. Bacterial strains Fungal strains

B.

subtilis

E.

coli

S.

aureus

K.

pneumoniae

A.

niger

A.

flavus

F.

oxisporium

C.

albicans

27 ＞6.25 12.5 ＞6.25 12.5 ＞25 ＞25 25 25

28 >6.25 >6.25 12.5 12.5 25 >25 >25 25

Rani et al. synthesized a new series of N-(3-chloro-2-oxo-4-substituted

phenylazetidin-1-yl) isonicotinamides and screened their antibacterial activity against

Gram-positive bacteria such as S. aureus (NCIM 2079) and B. subtilus (NCIM 2063)

and Gram-negative bacteria E. coli (NCIM 2068) and P. aeruginosa (NCIM 2200).

Compound 29 showed significant antibacterial activity with zone of inhibition

diameters 23, 21, 24 and 22 mm against S. aureus, B. subtilis, E.coli and P.

aeruginosa respectively and the results were compared with standard drug ampicillin

(Rani et al., 2012).

Wadher et al. synthesized Schiff base, azetidinone and 4-thiazolidinone

derivatives of para aminosalicylic acid and screened their in vitro antimicrobial

activity. Compound 30 was found to be more active against all the microorganisms

tested with zone of inhibition of 24.6 24.8 22.2 and 22 mm against S. aureus, E. coli,

C. albicans and A. niger respectively (Wadher et al., 2009).

N

O

HN

N

O

Cl

Cl

O

HO

HO

O

O

Cl

29 30

2.3.2. Anticancer activity

Two 2H-azirine-2-azetidinones were synthesized by Maia et al. The

compounds were assayed for their antibacterial and cytotoxic activities. None of the

synthesized compounds showed antibacterial activity on the tested bacterial strains (S.

aureus ATCC 6538; P. aeruginosa ATCC 9027 and E. coli ATCC 8739). Both 2H-

azirine and 2-azetidinones showed cytotoxicity against four tumor cell lines (HL-60,

leukemia; HCT-8, colon cancer; MDA-MB-435, melanoma; and SF-295, CNS). The


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57

IC50 values of 1-(4-chlorophenyl)-3,3-diphenyl-2-(3-phenyl-2H-azirin-2-yl)azetidine

(31) ranged from 1.1 to 10.5 µM and from 3.8 to 26.6 µM for 3,3-diphenyl-2-(3-

phenyl-2H-azirin-2-yl)-1-p-tolylazetidine (32) (Maia et al., 2009).

NH N

Cl

NH N

CH3

31 32

A novel series of 3-chloro-4-[4-(2-oxo-2H-chromen-4-ylmethoxy)-phenyl]-1-

phenyl-azetidin-2-one derivatives were synthesized by Keri et al. and were screened

for its in vitro antibacterial antifungal and cytotoxic activities. The antibacterial

activity of synthesized compounds against S. aureus, Vancomycin resistant

enteroccus as Gram (+), E. coli, S. dysentery as Gram (-) bacteria showed good

potencies compared to control drug ciprofloxacin. Compound 33 showed excellent

activity with an MIC of 1 µg/ml against all bacterial strains which is comparable with

ciprofloxacin. The antifungal screening of all compounds was carried out against A.

fumigatus, C. albicans and Penicillium fungal strains using gentamycin as standard

drug. Compound, 3-chloro-4-(4-((6-chloro-2-oxo-2H-chromen-4-yl)methoxy)phenyl)-

1-(4-chlorophenyl)azetidin-2-one (33) was showed promising activity with MIC of 8

µg/ml against both the fungi. Brine shrimp bioassay was also carried out to study their

in vitro cytotoxic properties showed that compound 1-(4-bromo phenyl)-3-chloro-4-

(4-((6-chloro-2-oxo-2H-chromen-4-yl)methoxy) phenyl) azetidin-2-one (34) with

maximum activity (LD50=7.421X10-4

M) against Artemia salina. The DNA cleavage

activity of some compounds was studied by agarose gel electrophoresis method (Keri

et al., 2009).

A series of 1,3,4-trisubstituted and 3,4-disubstituted 2-azetidinones were

synthesized by Veinberg et al. and screened for its in vitro cytotoxic study toward

tumor cells of human fibrosarcoma and mouse hepatoma. Among the synthesized

derivatives, compounds (3S,4S)-4-(2-Acetoxybenzoyloxymethyl)-1-(4-


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58

methoxyphenyl)-3-methyl-2-azetidinone (35) and (3S,4S)-4-(2,2-Dicyanovinyl)-1-(4-

methoxyphenyl)-3-methyl-2-azetidinone (36) were the most active ones. The TD50

value of compound 35 was 1 µg/mL for Human Fibrosarcoma and TD50 value of

compound 36 was 0.5 µg/mL for mouse hepatoma (Veinberg et al., 2003).

O

O

O

NO

ClCl

Cl

O

O

O

NO

ClCl

Br

33 34

N

O

O

O

O

O

O

N

O

O

N

N

35 36

2.3.3. Antimycobacterial activity

Pathak et al. synthesized a series of 3-(4-chlorophenyl)-4-substituted pyrazole

derivatives and tested for its in vitro antitubercular activity against

Mycobacterium tuberculosis H37Rv strain using the BACTEC 460 radiometric

system. Synthesized compounds generally possess very good antimycobacterial

activity, with MIC values in the range of 0.35–3.15 µg/mL, best activity against M.

tuberculosis H37Rv was observed for the 2-OH substituted azetidinone derivative 37,

which was only slightly less potent than the standard drug rifampin (MIC = 0.35

µg/mL). In general, the substituent (Cl) is important for biological potency, thus, the

substituents appear to be an important factor in their antimycobacterial activity

(Pathak et al., 2012).

A series of potentially active quinoline-based azetidinone and thiazolidinone

analogues has been synthesized by Mistry et al. and examined for its antimicrobial

activity against two Gram -ve bacteria (E. coli MTCC 739, P. aeruginosa MTCC

741), two Gram + ve bacteria (S. aureus MTCC 96, Bacillus subtilis MTCC 430) and

two fungal species (Aspergillus niger MTCC 282, Candida albicans MTCC 183) as


derivatives



59

well as antituberculosis activity against Mycobacterium tuberculosis. Streptomycin,

isoniazid, rifampicin and ethambutol were used as standards. Compounds 38 and 39

with electron withdrawing nitro and electro withdrawing halo (–Cl, F) substituents

demonstrated potential antimicrobial properties. Preliminary antitubercular screening

results revealed that compounds 38 and 39 displayed appreciable inhibition at a

concentration of 62.5 µg/mL against M. tuberculosis H37Rv (Mistry et al., 2013a).

HN N

O

HN Cl

NO

N+O

O-

Cl

N

O

NHS

Cl

Cl

N

O

NHS

F

Cl

37 38 39

Dubey et al. synthesized a series of 2-oxo-4-substituted aryl-azetidine

derivatives of benzotriazole and evaluated its antitubercular activity against

Mycobacterium tuberculosis H37RV and antimicrobial activity against some selected

microorganisms. Generally compounds possessing electron withdrawing groups

showed good antibacterial and antitubercular activity. Some derivatives (40 and 41,)

containing electron withdrawing groups (–Br, –NO2) have shown promising activity

against M. tuberculosis (MIC > 1.56 µg/ml). Compounds possessing electron

donating groups (42 and 43) have shown good antifungal activity (MIC= 0.1 µg/ml)

(Dubey et al., 2011).

NN

N

NN

O Cl

N+ O

-O

NN

N

NN

O

Cl

Br

40 41

A novel series of 14 new isonicotinyl hydrazide derivatives containing a

4-thiazolidinone/2-azetidinone nucleus were synthesized by Jaju et al. and tested for

its in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv

using Alamar-Blue susceptibility test. Amongst the synthesized compounds,


derivatives



60

compound 45 (MIC = 0.31 µg/mL) exhibited a significant activity and compound 44

(MIC = 0.62 µg/mL) showed a respectable activity when compared with first-line

drugs such as isoniazid (MIC = 0.2 µg/mL) and rifampicin (MIC = 1.0 µg/mL) (Jaju

et al., 2009).

NN

N

NN

O

Cl

O

NN

N

NN

O Cl

O

42 43

N

OHN

O

Cl

OH

N

OHN

O

Cl

H3CO

OH

44 45

New azetidinone and thiazolidinone class of bioactive agents based on

quinoline nucleus have been synthesized by Mistry et al. and were then examined for

antimicrobial activity against against two Gram (-ve) bacteria (E. coli MTCC 739 and

P. aeruginosa MTCC741), two Gram (+ve) bacteria (S. aureus MTCC 96 and B.

subtilis MTCC 430), two fungal species (A. niger MTCC 282 and C. albicans MTCC

183) as well as against Mycobacterium tuberculosis strain H37Rv. The insertion of

electron withdrawing p-nitro aniline substituent to the azetidinone (46) proved

beneficial to display strong activity against S. aureus and P. aeruginosa (12.5

µg/mL). Compound 47 with strong electro-negative fluoro substituents showed good

antifungal activity against both the tested fungal strains at the MIC range 12.5–50

µg/mL. The antimycobacterial biological screening was performed using Lowenstein–

Jensen (L–J) MIC method indicated that compound 48 with 2-amino 5-methyl

thaizole moiety to the azetidinone exhibited good inhibitory potential at 12.5 µg/mL

of MIC against H37Rv (Mistry et al., 2013b).


derivatives



61

Sharma et al. synthesized a series of N-[2-(10H-phenothiazinyl)ethyl]-4-

(phenyl)-3-chloro-2-oxo-1-iminoazetidine and evaluated its antibacterial, antifungal

and antitubercular activities. Nitro group containing compounds (49 and 50) showed

higher activity than chloro, or bromo group containing compounds. Compunds 49 and

50 exhibited good inhibitory potential at 2.50 μg/mL against H37Rv strain (Sharma et

al., 2011).

N

O

N+

O

-O NCl

Cl

N

O

FN

Cl

Cl

N

O

S

NN

Cl

Cl

46 47 48

Ilango et al. synthesized a series of trihydroxy benzamido azetidin-2-one

derivatives and screened its antimicrobial and antitubercular activities. Compound 51

with chloro phenyl group exhibited good antimicrobial activity value (1.56-6.25)

which was similar to standard drugs, ciprofloxacin and ketoconazole. Compound 51

(MIC = 0.57 µg/ml) also showed antitubercular activity with minimum inhibitory

concentration (MIC) values equivalent to the standard drug (isoniazid). MIC value of

compound 51 was 0.57μg/ml, while the MIC of isoniazid was 0.56 (Ilango et al.,

2011).

N

S

CH2CH2NH

NCH

Cl

O

NO2

N

S

CH2CH2NH

NCH

Cl

ONO2

N

O

O

NHHO

HOOH

Cl

Cl

49 50 51

2.3.4. Anti-inflammatory and analgesic activity

Kumar et al. (2007) synthesized 3-[4’-(p-chlorophenyl)-thiazol-2’-yl]-2-

[(substituted azetidinone/thiazolidinone)-aminomethyl]-6-bromoquinazolin-4-ones

and screened their anti-inflammatory and analgesic activities at the dose of 50 mg/kg

p.o. using phenylbutazone as reference drug. Compound 52 showed maximum anti-


derivatives



62

inflammatory (34.21%) and analgesic (34.11%) activities as compared to the standard

drug phenyl-butazone.

Samadhiya et al. synthesized a new series of 3-chloro-1-{[2-(6-nitro-1H-

indazol-1-yl)ethyl]amino}-4-(substituted phenyl)-2-azetidinones and tested its in vitro

for their antibacterial, antifungal and antitubercular activities as well for its their anti-

inflammatory activity. Data of all activities revealed that the compound 53 displayed

higher activities than the other compounds of the series. The MIC (μg/mL) values of

antimicrobial activity for compound 53 was found to be 3.25 for all bacteria, >12.5

for all fungi and 2.5 for Mycobacterium tuberculosis H37Rv strain. Compound 53

showed maximum anti-inflammatory (68.75%) activity (Samadhiya et al., 2012).

N

SN

N

O

H2C

Cl

Br

NH NHC

C CH

O ClCl

N

ON+

O

-O

HN

N

N

N+

O O-

Cl

52 53

Rajasekaran et al. synthesized a series of seven novel azetedinones and

evaluated its antitubercular, antibacterial, antifungal and anti-inflammatory activities

by Lowenstein-Jensen medium method, cup plate method, disc diffusion method and

carrageenan induced paw edema method respectively. The standard drugs used were

streptomycin for bacteria, clotrimazole for fungi and pyrazinamide for antitubercular

activity. None of the reported compounds showed antimicrobial or antitubercular

activities. Compound 54 showed maximum anti-inflammatory among the synthesized

compounds as compared to phenyl-butazone (Rajasekaran et al., 2010).

2.3.5. Anticonvulsant activity

Hasan et al. synthesized a new series of N-[3-chloro-2-(substitutedphenyl)-4-

oxo-azetidin-1-yl]isonicotinamide derivatives and were evaluated for its

anticonvulsant activity. The anticonvulsant effect and the neurotoxicity of the

compounds were calculated with MES test, Sc-PTZ, and rotarod tests with

intraperitoneally injected mice. Among the synthesized compounds, N-[3-chloro-2-(4-

methylphenyl)-4-oxoazetidin-1-yl]isonicotinamide (55) exhibited the highest

antimicrobial activity at minimum dose 30 mg/kg in maximum electroshock seizure


derivatives



63

(MES) at both 0.5 and 4.0 h and 100 and 30 mg/kg, i.p. in subcutaneous

pentylenetetrazole (scPTZ) at 0.5 and 4.0 h, respectively (Hasan et al., 2011).

N

S

COCH2NH

N Cl

O

OCH3

OCH3

N

O

HN

N

O

Cl

54 55

2.3.6. Antidiabetic activity

Goel et al. synthesized a series of 2-azetidinone derivatives and evaluated its

antihyperglycemic activity against alloxan-induced diabetes in rats. In the diabetic

rats, high glucose levels and depression in hepatic glycogen contents were observed

which could be attributed to the less availability of active form of enzyme glycogen

synthetase. Test compounds significantly lowered the serum glucose levels indicating

their anti-hyperglycemic activity. Most active compound of this series was (E)-2-(1-

isopropyl-2-oxo-4-styrylazetidin-3-yl)isoindoline-1,3-dione (56) (Goel et al., 2004).

NO

H3C CH3

OO N

56

2.3.7. Antiviral activity

Pandey et al. synthesized a series of 1-[m-(aralkylamido/imidoalkyl/2-phenyl-

3-ethyl-3H-4-oxo-quinazolinyl-benzamido)]-3-phenoxy-4-phenyl-2-azetidinone

derivatives and screened its antiviral activity against two human viruses viz. Japanese

encephalitis virus (JEV) P-20778 and herpes simplex virus (HSV-I) 753166 as well as

against viz. tobacco mozaic virus (TMV). Compound 57 showed low order of activity


derivatives



64

against the tested viruses. Compound 58 displayed high anti-TMV activity with 70%

inhibition (Pandey et al., 2005).

OCHN N O

O

CH

OHCN

HO

OCHN N O

O

CH2

OHCN

N

57 58

2.3.8. Cholesterol absorption inhibitory activity

Atherosclerotic coronary heart disease (CHD) remains a major concern in

healthcare due to its high morbidity and mortality. Lowering the level of cholesterol

in blood has been shown to be an effective way to treat and prevent CHD. 2-

Azetidinone analogs were designed and synthesized by Xu et al. Their effects on the

cholesterol levels in rat serum were evaluated by a high-cholesterol and high-fat diet

feeding experiment. All the new analogs showed significant effect in lowering the

levels of total cholesterol in serum. Among these synthesized derivatives compounds

59 and 60 demonstrated significant effect in lowering the total cholesterol (-25% and -

29%) and LDL (-18% and -35%) in serum respectively (Xu et al., 2007).

N

OH

OH

O

F

F

N

OH

O

F

F

OH

59 60

Wang et al. synthesized new derivatives of the 2-azetidinone and evaluated

their potential to inhibit cholesterol absorption in rats. Most of the synthesized

compounds showed comparable effects in lowering the levels of total cholesterol in

the serum. Compounds 61 and 62 could raise high-density lipoprotein cholesterol


derivatives



65

(HDL-C) levels markedly (35% and 32.9%). Which may consider to be good for

prevention and treatment of CHD (Wang et al., 2009).

N O

OHO

F

N O

OHO

F

F

Br

61 62

Burnett et al. designed and synthesized a series of radioiodinated analogues of

2-azetidinone as cholesterol absorption inhibitors. Among the synthesized derivatives

compounds 63 and 64 were found to be the most active with cholesterol absorption

inhibitory values -63% and -54% respectively (Burnett et al., 2002).

O

I

OH

F

OH

O

I

O

F

OH

O

OH

HO OH

COOH

63 64

2.3.9. Tryptase inhibitory activity

The serine protease tryptase, which is the major protein component of mast

cells, is released along with histamine, chymase, and other mediators of inflammatory

and allergic responses when mast cells degranulate upon stimulation. Tryptase has

been implicated in inflammatory and allergic diseases and is believed to play a

significant role in asthma. Consequently, inhibition of tryptase has become an

important therapeutic target for asthma and other inflammatory and allergic

conditions. Bisacchi et al. discovered a number of potent azetidinone tryptase

inhibitors in which the guanidine moiety at the ring C-3 position is replaced with

primary or secondary amine or aminopyridine functionality. In particular, BMS-


derivatives



66

354326 (65) showed excellent selectivity against trypsin and most other related serine

proteases tested (Bisacchi et al., 2004).

Sutton et al. synthesized a novel series of nonguanidine N1-activated C4-

carboxy azetidinone derivatives and were screened for its human tryptase inhibitory

activity. Compounds 66 and 67 showed comparable improvements in activity against

tryptase (IC50 = 0.001µM). Selectivity screening of selected compounds against

trypsin, thrombin, plasmin, factor Xa, urokinase (uPA), and tissue plasminogen

activator (tPA) showed the piperidine containing compounds (66, 67, and 68) had

high selectivity against thrombin, factor Xa and tPA. Potency toward plasmin was

variable, with 67 and 68 being more potent against plasmin, but due to their potency

against tryptase they retained a moderate level of selectivity. When compared to

compound 66, compounds 67 and 68 showed improved selectivity against trypsin and

uPA (Sutton et al., 2004).

NO

COOH

N

O

N

O

HN

N

OOH

HN

O O

N N

O

H2C O

H2C

65

67

N

OOH

HN

O O

N N

O

NH

N

OOH

HN

O O

N N

O

66 68

A series of N1-activated C4-carboxy azetidinones was prepared by Sutton et

al. and tested as inhibitors of human tryptase. Compound, BMS-262084 (69) was

identified as a potent and selective tryptase inhibitor (IC50 = 4 nM) with a moderate to

good selectivity profile and reduced the bronchoconstriction and the cellular

inflammatory response in ovalbumin-sensitized guinea pigs (Sutton et al., 2002).

N

OOH

O O

N N

O

NHH2N

HN

69


derivatives



67

2.3.10 Vasopressin VIa antagonist activity

A novel series of 2-azetidinones was synthesized by Guillon et al. and

screened for vasopressin VIa antagonist activity. The azetidinone LY307174 (70) was

identified as a screening lead for the vasopressin V1a receptor (IC50 = 45 nM at the

human V1a receptor) based on molecular similarity to ketoconazole, a known

antagonist of the luteinizing hormone releasing hormone receptor (Guillon et al.,

2007).

O

O

NO

O

O

OO

70

2.4 Conclusion

This review focuses on diverse and potent biological activity profile of 2-

azetidione derivatives reported in the past new millennium. The 2-azetidinone

derivatives have demonstrated significant antimicrobial, anticancer, antitubercular,

anti-inflammatory, anticonvulsant, antidiabetic, antiviral, cholesterol absorption

inhibitory, tryptase inhibitory, vasopressin V1a antagonistic activities.

Chapter-2. A comprehensive review on biological activities...

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