Abstract:
The present invention provides a new class of compounds 4β-1″-[{2″-benzoyl substituted}anilino]podophyllotoxin exhibiting anti cancer activity and a process for preparing the same.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to a process for the synthesis of new 4β-1″-[2″-(substituted benzoyl)anilino]podophyllotoxin analogues are useful anticancer agents. The present invention particularly relates to the synthesis of new class of 4β-O-benzoyl anilino congeners of the podophyllotoxin as useful anticancer agents.  
       BACKGROUND ART  
       [0002]     Etoposide and teniposide two synthetic podophyllotoxin derivatives which are important drugs that currently being used in the treatment of small lung cancer, testicular carcinoma, lymphoma, Kaposi&#39;s sarcoma. The clinical efficacy and intriguing mechanism of etoposide has greatly stimulated interest in further studies on the modification of the C-4 substution of this compound and for better antitumour activity (Jadine, I. In  Anticancer Agents Based on Natural Products Models;  Cassady, J. M., Dours, J., Eds.; Academic press: New York, 1980, p 319.; Levy, R. K.; Hall, I. H.; Lee, K. H.  J. Pharm. Sci.  1983,72,1158.; Issell, B. F.; Muggia, F. M.; Carter, S. K.  Etoposide  [VP-16 ]Current Status and New Developments;  Academic Press New York, 1984.; Stio, H.; Yoshikawa, H.; Nishimura, Y.; Kondo, S.; Takeuchi, T.; Umezawa, H.  Chem. Pharm. Bull.  1986,34,3733. Satio, H.; Nishimura, Y.; Kondo, S.; Komuro, K.; Takeuchi, T.;  Bull. Chem. Soc. Jpn. 1988, 61, 2493). It has been well established that the principal mechanism of the action for etoposide is by the inhibition of catalytic activity of DNA topoisomarase II and concurrent enzyme mediated production of lethal DNA strand breaks. Structure activity relationship studies for the podophyllotoxin-derived compounds have shown the trans C/D ring juncture is a essential for the antitumour activity. A number of studies have been carried out on the structural modification of glycoside moiety by 4-alkylamino or 4-arylamino substituents have improved the inhibitory activity on human DNA topoisomarase II as well as stronger activity in causing cellular protein length DNA breakage (Lee. K. H.: Imakura. Y.: Haruna. M.; Beers, S. A.; Thurston, L. S.; Dai, H. J.; Chen, C. H.; Liu, S. Y.; Cheng, Y. C.  J. Nat. Prod.  1989, 52, 606. Liu, S. Y.; Hawang, B. D.; Haruna, M.; Imakura, Y.; Lee, K. H.; Cheng, Y. C.  Mol. Pharmcol.  1989, 36, 78. Lee, K, H.; Beers, S. A.; Mori, M.; Wang, Z. Q.; Kuo, Y. H.; Li, L.; Liu, S. Y.; cheng, Y. C.;  J. Med. Chem.  1990, 33,1364). In the context a large number of 4β-aryl amino derivatives of 4′-O-demethyl epipodophyllotoxin based compound have been synthesized and investigated for their antitumour activity.  
       OBJECTIVES OF THE INVENTION  
       [0003]     The main object of the invention is to provide the new 4β-[2″-benzoylsubstituted]arylamino podophyllotoxin analogues useful as anticancer agents.  
         [0004]     Another object of the present invention is to provide a process for the synthesis of new 4β-1″-[{2″-benzoyl substituted}anilino]podophyllotoxin derivatives as useful anticancer agents, which obviates the draw backs as detailed above.  
         [0005]     Another object of the present invention is to provide new and stereo-selective compounds of the podophyllotoxins and 4′-O-demethylepipodophyllotoxin in good yields.  
         [0006]     Still another object of the present invention is to provide the key step for the synthesis of these analogues by direct nucleophilic substitution of the C-4β-bromo intermediate.  
       SUMMARY OF THE INVENTION  
       [0007]     The above and other objective of the present invention are achieved by providing the new class of C 4 - 62  -aryl substituted and N-linked derivatives of podophyllotoxin and 4′-O-demethylepipodophyllotoxin, which have been synthesized as anti cancer agents.  
         [0008]     Accordingly, the present invention provides new class of 4β-1″-[(2″-benzoyl substituted}anilino]podophyllotoxin analogues having the structural formula (2). The present invention also provides a process for the preparation of new 4β-1″-[2″-(substituted benzoyl)anilino]podophyllotoxin analogues as useful anticancer agents. More particularly, it provides a process for the preparation of 4β-1″-[2″-(substituted benzoyl)anilino] derivatives of podophyllotoxin. 
     
    
     BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS  
       [0009]      FIG. 1  represents structure of podophyllotoxin, Etoposide and Teniposide.  
         [0010]      FIG. 2  represents general formula of compounds of the class 4β-1″-[{2″-benzoyl substituted}anilino]podophyllotoxin analogues.  
         [0011]      FIG. 3  discloses the process for the synthesis of new podophyllotoxin analogues as anticancer agents producing the novel and stereo-selective derivatives of the podophylotoxin in good yields. 
     
    
     DETAILED DESCRIPTION  
       [0012]     The process for the synthesis of new podophyllotoxin analogues as anticancer agents produces the novel and stereo-selective derivatives of the podophyllotoxin in good yields, where in the key step for the synthesis of these analogues is by direct nucleophilic substitution of C-4β-bromo intermediates, 4β-bromo-podophyllotoxin and 4′-O-demethylepipodophyllotoxin, which have been reacted with substituted or unsubstituted 2-aminobenzophenones in a stereo-selective manner to afford the 4β-1″-[{2″-benzoyl substituted}anilino]podophyllotoxin derivatives.  
         [0013]     These 4-bromopodophyllotoxin intermediates have been prepared by the bromination of the related podophyllotoxin compounds as described in the literature [Kuhn, M.; Keller-Juslen, C.; Van Wartburg,  Helv. Chemica. Acta,  1969, 52, 944].  
         [0014]     In an embodiment of the present invention, the naturally occurring podophyllotoxin lignan was isolated from  Podophyllum peltatum linnaeus.    
         [0015]     In another embodiment of the present invention the synthesis of 4β-intermediates have been carried out from bromination of podophyllotoxin and 4′-O-demethylepipodophyllotoxin.  
         [0016]     In yet another embodiment of the present invention 1-2 eq. of different unsubstituted and substituted benzophenone compounds have been used.  
         [0017]     In still another embodiment of the present invention a variety of solvents were used for the nucleophilic substitution step, such as dichloromethane, chloroform and tetrahydrofuran.  
         [0018]     In still yet another embodiment of the present invention catalytic amount of BU 4 N + I −  (0.2-0.5 eq) was used by stirring the reaction mixture between −10° C. to room temperature for 2 to 10 h.  
         [0019]     In still another embodiment of the present invention bases like K 2 CO 3 , Et 3 N were also used.  
         [0020]     In still another embodiment of the present invention the purification of these analogues was done by column chromatography employing chloroform/methanol as eluent.  
         [0021]     Thus, the present invention provides new classes of podophyllotoxin analogues, which were synthesized in a stereo selective manner.  
         [0022]     A program was initiated in the laboratory for the design and synthesis of new 4β-aryl amino substituted podophyllotoxin congeners with enhanced antitumour activity and/or activity against etoposide resistant tumor cell lines. In these efforts new 4β-1″-[{2″-benzoyl substituted}anilino]podophyllotoxin derivatives have been synthesized and evaluated for their cytotoxicity and anticancer potency. Interestingly, some of the compounds have shown greater in vitro cytotoxicity values compared to etoposide. The synthesis of these compounds has been carried out as described in the scheme using podophyllotoxin obtained from the resin. The cytotoxicity of 4a-4p values have been illustrated in the Table 1.  
                                         TABLE 1                           Cytotoxicity (in vitro) data for some representative compounds.                                                                  S. No.   R   R 1     R 2     GI 50  μM                       4a   CH 3     H   H     0.04-0.5           4b   H   H   H    15-382           4c   CH 3     2-Cl   4-Cl     0.059-0.876           4d   H   2-Cl   4-Cl     0.1-0.24           4e   CH 3     H   4-NO 2     &lt;10 nM-0.28           4f   H   H   4-NO 2       0.01-0.24           4g   CH 3     H   4-Cl     0.07-1.1           4h   H   H   4-Cl    14-270           4i   CH 3     2-F   4-Cl     0.14-0.3           4j   H   2-F   4-Cl     0.004-0.1           4k   CH 3     H   H     0.1-1           4l   H   H   H     2-16           4m   CH 3     H   4-NO 2       0.01-0.2           4n   H   H   4-NO 2       0.01-0.24           4o   CH 3     H   4-NH 2       0.04-1           4p   H   H   4-NH 2       0.015-0.4                      
 
         [0023]     Some of the compounds of the present invention are given below: 
        a) 4β-1″-[2″-(Benzoyl)anilino]-4-desoxypodophyllotoxin     b) 4′-O-Demethyl-4β-1″-[2″-(benzoyl)anilino]-4-desoxypodophyllotoxin     c) 4β-1″-[2″-(2-Chlorobenzoyl)-4″-chloroanilino]-4-desoxypodophyllotoxin     d) 4′-O-1″-[2″-(2-Chlorobenzoyl)-4″-chloroanilino]-4-desoxypodophyllotoxin     e) 4β-1″-[2″-(Benzoyl)-4″-nitroanilino]-4-desoxypodophyllotoxin     f) 4′-O-Demethyl-4β-1″-[2″-(Benzoyl)]-4″-nitroanilino]-4-desoxypodophyllotoxin     g) 4β-1″-[2″-(Benzoyl)-4″-chloroanilino]-4-desoxypodophyllotoxin     h) 4′-O-Demethyl-4β-1″-[2″-(Benzoyl)]-4″-chloroanilino]-4-desoxypodophyllotoxin     i) 4β-1″-[2″-(2-Fluorobenzoyl)-4″-chloroanilino]-4-desoxypodophyllotoxin     j) 4′-O-Demethyl-4β-1″-[2″-(2-Fluorobenzoyl)-4″-chloroanilino]-4-desoxypodophylltoxin     k) 4β-1″-[3″-(Benzoyl)anilino]-4-desoxypodophyllotoxin     l) 4′-O-Demethyl-4β-1″-[3″-(benzoyl)anilino]-4-desoxypodophyllotoxin     m) 4β-1″-[2″-(Benzoyl)-2 ″-nitroanilino]-4-desoxypodophyllotoxin     n) 4′-O-Demethyl-4β-1″-[4″-(Benzoyl)]-2″-nitroanilino]-4-desoxypodophyllotoxin.        
 
         [0038]     The following examples are given by way of illustration and should not be construed the limit and the scope of the invention.  
         [0000]     Experimental  
       EXAMPLE 1  
     4β-1″-[2″-(Benzoyl)anilino]-4-desoxypodophyllotoxin (4a)  
       [0039]     4β-Bromo-4-desoxy-podophyllotoxin (0.1 g, 0.21 mmol) was reacted with 2-aminobenzophenone (0.045 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 4 h. After completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.8:0.2) as eluent.  
         [0040]     Yield 60%, mp 140° C.; [α] 25   D  −112 (c, 0.1 CHCl 3 )  
         [0041]      1 H NMR (200 MHz, CDCl 3 ): δ 8.82 (d, 1H), 7.50 (m, 7H), 6.80 (s, 1H), 6.75 (d, 1H), 6.68 (d, 1H), 6.55 (s, 1H), 6.35 (s, 2H), 5.96 (d, 2H), 5.38 (s, 1H), 4.92 (m, 1H), 4.65 (d, 1H), 4.35 (t, 1H), 3.96 (t, 1H), 3.82 (d, 9H), 3.20 (q, 1H), 3.50 (m, 1H)  
         [0042]     MS (m/e) 593 (M + , 40%), 576, 467, 397, 282, 229, 185.  
         [0043]     IR (KBr) cm −1 : 3400 (N—H), 2900 (aliphatic C—H), 1780 (lactone), 1650 (ketone), 1500, 1480, 1410, 1300, 1250 (aromatic C═C).  
       EXAMPLE 2  
       4 ′-O-Demethyl-4β-1″-[2″-(benzoyl)anilino]-4-desoxypodophyllotoxin (4b)  
       [0044]     4β-Bromo-4′-O-demethyl-4-desoxypodophyllotixin (0.1 g, 0.21 mmol) was reacted with 2-aminobenzophenone (0.045 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 4 h. After the completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.8:0.2) as eluent.  
         [0045]     Yield 50% m.p 154-156° C.; [α] 25   D  111 (c, 1.1, CHCl 3 )  
         [0046]      1 H NMR (200 MHz, CDCl 3 ): δ 8.85 (d, 1H), 7.50 (m, 7H), 6.80 (s, 1H), 6.75 (d, 1H), 6.68 (d, 1H), 6.55 (s, 1H), 6.35 (s, 2H), 5.96 (d, 2H), 5.38 (s, 1H), 4.92 (m, 1H), 4.65 (d, 1H), 4.35 (t, 1H), 3.96 (t, 1H), 3.82 (s, 6H), 3.20 (q, 1H), 3.05 (m, 1H)  
         [0047]     MS (m/e) 579(M + , 25%), 495, 467, 397, 229, 185.  
         [0048]     IR (KBr) cm −1 : 3550 (O—H), 3400(N—H) 2900 (aliphatic C—H), 1750 (lactone), 1650 (ketone), 1500, 1480, 1410, 1300, 1250 (aromatic C═C).  
       EXAMPLE 3  
     4β-1″-[2″-(2-Chlorobenzoyl)-4″-chloroanilino]-4-desoxypodophyllotoxin (4c)  
       [0049]     4β-bromo-4-desoxypodophyllotoxin (0.10 g 0.21 mmol) was reacted with 2-amino-2′, 5′-dichlorobenzophenone (0.06 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g 0.042 mmol) in dry tetrahydrofiuran at room temperature for 5 h. After the completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.7:0.3) as eluent.  
         [0050]     Yield 64% m.p 142-145° C.; [α] 25   D  −84 (c, 0.87, CHCl 3 )  
         [0051]      1 H NMR (200 MHz, CDCl 3 ): δ 9.10 (d, 1H), 7.40 (m, 5H), 7.20 (d, 1H), 6.78 (s, 1H), 6.75 (d, 1H), 6.52 (s, 1H), 6.35 (s, 2H), 5.96 (d, 2H), 4.97 (m, 1H), 4.65 (d, 1H), 4.35 (t, 1H), 3.90 (t, 1H), 3.77 (d, 9H), 3.20 (q, 1H), 3.10 (m, 1H)  
         [0052]     MS (m/e) 663 (M + , 20%), 662, 661, 460, 387, 289.  
         [0053]     IR (KBr) cm −1 : 3350 (N—H), 2900 (aliphatic C—H), 1760 (lactone), 1640 (ketone), 1550, 1480, 1250 (aromatic C═C).  
       EXAMPLE 4  
     4′-O-Demethyl-4β-1″-[2″-(2-Chlorobenzoyl)-4″-chloroanilino]-4-desoxypodo-phyllotoxin (4d)  
       [0054]     4β-Bromo-4′-O-Demethyl-4-desoxypodophyllotoxin (0.10 g 0.21 mmol) was reacted with 2-amino-2′, 5′-dichlorobenzophenone (0.06 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g 0.042 mmol) in tetrahydrofuran at room temperature for 5 h. After the completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.7:0.3) as eluent.  
         [0055]     Yield 70% m.p 151-153° C.; [α] 25   D  −91 (c, 0.93., CHCl 3 )  
         [0056]      1 H NMR (200 MHz, CDCl 3 ): δ 9.10 (d, 1H), 7.40 (m, 5H), 6.77 (s, 1H), 6.70 (d, 1H), 6.30 (s, 1H), 5.96 (d, 2H), 5.40 (s, 2H), 4.90 (m, 1H), 4.65 (d, 1H), 4.30 (t, 1H), 4.10 (t, 1H), 3.80 (s, 6H), 3.20 (q, 1H), 3.10 (m, 1H).  
         [0057]     MS (m/e) 649 (M + , 20%), 648, 647, 446, 383, 289.  
         [0058]     IR (KBr) cm −1 : 3320 (N—H), 2900 (aliphatic C—H), 1760 (lactone), 1650 (ketone), 1550, 1480, 1410, 1250 (aromatic C═C).  
       EXAMPLE 5  
     4β-1″-[2″-(Benzoyl)-4″-nitroanilino]-4-desocypodophyllotocin (4e)  
       [0059]     4β-Bromo-4-desoxypodophyllotoxin (0.1 g, 0.21 mmol) was reacted with 2-amino-5-nitro-benzophenone (0.056g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 8 h. After completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.5:0.5) as eluent.  
         [0060]     Yield 40%, mp 163-167° C.; [α] 25   D  −85 (c, 1.2, CHCl 3 )  
         [0061]      1 H NMR (200 MHz, CDCl 3 ): δ 9.50 (d, 1H), 8.57 (d, 1H), 8.32 (q, 1H), 7.60 (m, 4H), 6.75 d, 1H), 6.75 (s, 1H) 6.60 (d, 1H), 6.40 (d, 1H), 6.30 (s, 2H), 6.00 (d, 2H), 5.05 (m, 1H), 4.70 (d, 1H), 4.40 (t, 1H), 3.90 (t, 1H) 3.80 (d, 9H), 3.15 (d, 1H), 2.95 (m, 1H)  
         [0062]     MS (m/e) 638 (M + , 10%), 582, 496, 439, 411, 383, 289.  
         [0063]     IR (KBr) cm −1 : 3450 (N—H), 2950 (aliphatic C—H), 1740 (lactone), 1650 (ketone), 1550, 1480, 1250 (aromatic C═C).  
       EXAMPLE 6  
     4′-O-Demethyl-4β-1″-[2″-(Benzoyl)]-4″-nitroanilino]-4-desoxypodophyllotoxin (4f)  
       [0064]     4β-Bromo-4′-O-demethyl-4-desoxypodophyllotoxin (0.1 g, 0.21 mmol) was reacted with 2-amino-5-nitro-benzophenone (0.056 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.15 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 8 h. After completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.5:0.5) as eluent.  
         [0065]     Yield 38%, mp 169-171° C.; [α] 25   D  −89 (c, 1.0, CHCl 3 )  
         [0066]      1 H NMR (200 MHz, CDCl 3 ): δ 9.47 (d, 1H), 8.55 (d, 1H), 8.30 (q, 1H), 7.60 (m, 4H), 6.80 (d, 1H), 6.55 (s, 1H) 6.35 (d, 1H), 6.30 (s, 2H), 6.00 (d, 2H), 5.87 (s, 1H), 5.00 (m, 1H), 4.65 (d, 1H), 4.30 (m, 2H), 3.80 (d, 6H), 3.15 (d, 1H), 2.00 (m, 1H)  
         [0067]     MS (m/e) 624(M + , 15%), 568, 401, 383,289, 229, 185.  
         [0068]     IR (KBr) cm −1 : 3560 (O—H), 3400 (N—H) 2900 (aliphatic C—H), 1740 (lactone), 1650 (ketone), 1500, 1480, 1250 (aromatic C═C).  
       EXAMPLE 7  
     4β-1″-[2″-(Benzoyl)-4″-chloroanilino]-4-desoxypodophyllotoxin (4g)  
       [0069]     4β-bromo-4-desoxypodophyllotoxin (0.10 g 0.21 mmol) was reacted with 2-amino-5-chlorobenzophenone (0.053 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + F −  (0.015 g 0.042 mmol) in at room tetrahydrofuran temperature for 6 h. After the completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.7:0.3) as eluent.  
         [0070]     Yield 56% m.p 139-142° C.; [α] 25   D  −103 (c, 0.93, CHCl 3 )  
         [0071]      1 H NMR (200 MHz, CDCl 3 ): δ 8.72 (d, 1H), 7.60 (m, 7H), 7.45 (q, 1H), 6.80 (s, 1H), 6.75 (d, 1H), 6.55 (s, 1H), 6.35 (s, 2H), 5.98 (d, 2H), 4.95 (m, 1H), 4.65 (d, 1H), 4.40 (t, 1H), 3.95 (t, 1H), 3.80 (d, 9H), 3.20 (q, 1H), 3.10 (m, 1H)  
         [0072]     MS (m/e) 628 (M + , 20%), 627, 441, 383, 289, 229, 185  
         [0073]     IR (KBr) cm −1 : 3350 (N—H), 2900 (aliphatic C—H), 1780 (lactone), 1660 (ketone), 1500, 1480, 1410, 1250 (aromatic C═C).  
       EXAMPLE 8  
     4′-O-Demethyl-4β-1″-[2″-(Benzoyl)]-4″-chloroanilino]-4-desoxypodophyllotoxin (4h)  
       [0074]     4β-Bromo-4′-O-demethyl-4-desoxypodophyllotoxin (0.1 g, 0.21 mmol) was reacted with 2-amino-5-chlorobenzophenone (0.053 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 6 h. After completion of the reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.7:0.3) as eluent.  
         [0075]     Yield 50%, mp 146-149° C.; [α] 25   D  −105 (c, 0.97, CHCl 3 )  
         [0076]      1 H NMR (200 MHz, CDCl 3 ): δ 8.68 (d, 1H), 7.52 (m, 7H), 7.35 (q, 1H), 6.72 (s, 1H), 6.65 (d, 1H), 6.50 (s, 1H) 6.30 (s, 2H), 5.96 (d, 2H), 5.35 (s, 1H), 4.85 (m, 1H), 4.60 (d, 1H), 4.30 (t, 1H), 3.85 (d, 1H), 3.80 (s, 6H), 3.10 (q, 1H), 3.00 (m, 1H)  
         [0077]     MS (m/e) 614 (M + , 10%), 613, 401, 383, 289, 229, 185  
         [0078]     IR (KBr) cm −1 : 3500 (O—H), 3360 (N—H) 2900 (aliphatic C—H), 1750 (lactone), 1640 (ketone), 1500, 1480, 1230 (aromatic C═C).  
       EXAMPLE 9  
     4β-1″-[2″-(2-Fluorobenzoyl)-4″-chloroanilino]-4-desoxypodophyllotoxin (4i)  
       [0079]     4β-bromo-4-desoxypodophyllotoxin (0.10 g 0.21 mmol) was reacted with 2-amino-5-chloro-2′-fluorobenzophenone (0.057 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g 0.042 mmol) in dry tetrahydrofuran at room temperature for 5 h. After the completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.7:0.3) as eluent.  
         [0080]     Yield 68% m.p 123-128° C.; [α] 25   D  −89 (c, 1.0, CHCl 3 )  
         [0081]      1 H NMR (200 MHz, CDCl 3 ): δ 9.10 (d, 1H), 7.45 (m, 6H), 6.80 (s, 1H), 6.75 (d, 1H), 6.55 (s, 1H), 6.35 (s, 2H), 6.00 (d, 2H), 4.95. (m, 1H), 4.70 (d, 1H), 4.40 (t, 1H), 3.95 (t, 1H), 3.82 (d,9H), 3.10(m,1H)  
         [0082]     MS (m/e) 646 (M + , 30%), 645, 631, 411, 397, 229, 185  
         [0083]     IR (KBr) cm −1 : 3400 (N—H), 2950 (aliphatic C—H), 1760 (lactone), 1650 (ketone), 1500, 1480, 1300, 1250 (aromatic C═C).  
       EXAMPLE 10  
     4′-O-Demethyl-4β-1″-[2″-(2-Fluorobenzoyl)-4″-chloroanilino]-4-desoxypodo-phyllotoxin (4j)  
       [0084]     4β-Bromo-4′-O-Demethyl-4-desoxypodophyllotoxin (0.10 g 0.21 mmol) was reacted with 2-amino-5-chloro-2-fluorobenzophenone (0.057 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g 0.042 mmol) in dry tetrahydrofuran at room temperature for 5 h. After the completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.7:0.3) as eluent.  
         [0085]     Yield 60% m.p 164-167° C.; [α] 25   D  −85 (c, 1.01, CHCl 3 )  1 H NMR (200 MHz, CDCl 3 ): δ 9.05 (d, 1H), 7.48 (m, 6H), 6.80 (s, 1H), 6.75 (d, 1H), 6.52 (s, 1H C-8), 6.35 (s, H), 6.00 (d, 2H), 5.10 (s, 1H), 4.98 (m, 1H), 4.70 (t, 1H), 4.40 (t, 1H), 3.95 (t, 1H), 3.82 (s, 6H), 3.20 (q, 1H), 3.10 (m, 1H).  
         [0086]     MS (m/e) 632 (M + , 25%), 631, 401, 383, 229, 185  
         [0087]     IR (KBr) cm −1 : 3520 (O—H), 3440(N—H), 2900 (aliphatic C—H), 1750 (lactone), 1650 (ketone), 1500, 1480, 1300, 1250 (aromatic C═C).  
       EXAMPLE 11  
     4β-1″-[3″-(Benzoyl)anilino]-4-desoxypodophyllotoxin (4k)  
       [0088]     4β-Bromo-4-desoxypodophyllotoxin (0.1 g, 0.21 mmol) was reacted with 2-amino-4-bromobenzo-phenone (0.064 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 3 h. After completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.8:0.2) as eluent.  
         [0089]     Yield 61%, mp 141-144° C.; [α] 25   D  −102 (c, 1.1, CHCl 3 )  
         [0090]      1 H NMR (200 MHz, CDCl 3 ): δ 7.80 (d, 1H), 7.50 (m, 3H), 7.25 (d, 1H), 7.10 (d, 1H), 7.01(s, 1H), 6.80 (s, 1H), 6.75 (d, 1H), 6.50 (s, 1H), 6.28 (s, 2H), 5.95 (d, 2H), 5.30 (s, 1H), 4.75 (m, 1H), 4.55 (d, 1H), 4.40 (t, 1H), 4.00 (t, 1H) 3.75 (q, 9H), 3.05 (m, 2H)  
         [0091]     MS (m/e) 593 (M + 25%), 576, 467, 397, 229, 185.  
         [0092]     IR (KBr) cm −1 : 3400 (N—H), 2950 (aliphatic C—H), 1760 (lactone), 1650 (ketone), 1500, 1480, 1250 (aromatic C═C).  
       EXAMPLE 12  
     4′-O-Demethyl-4β-1″-[3″-(benzoyl)anilino]-4-desoxypodophyllotoxin (4l)  
       [0093]     4β-Bromo-4′-O-demethyl-4-desoxypodophyllotixin (0.1 g, 0.21 mmol) was reacted with 3-aminobenzophenone (0.045 g, 0.23) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 3 h. After the completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.8:0.2) as eluent.  
         [0094]     Yield 63% m.p 151-154° C.; [α] 25   D  −102; (c, 1.1. CHCl 3 )  
         [0095]      1 H NMR (200 MHz, CDCl 3 ): δ 7.84 (d, 2H), 7.52 (m, 3H), 7.25 (d, 1H), 7.10 (d, 1H), 7.01(s, 1H), 6.90 (s, 1H), 6.78 (d, 1H), 6.54 (s, 1H), 5.95 (d, 2H), 4.75 (m, 1H), 4.55 (d, 1H), 4.40 (t, 1H), 4.00 (t, 1H), 3.75 (d, 9H), 3.05 (m, 2H)  
         [0096]     MS (m/e) 579 (M + , 25%) 382, 283, 229, 185.  
         [0097]     IR (KBr) cm −1 : 3520 (O—H), 3390 (N—H) 2900 (aliphatic C—H), 1760 (lactone), 1650 (ketone), 1500, 1480, 1250 (aromatic C═C).  
       EXAMPLE 13  
     4β-1″-[2″-(Benzoyl)-2″-nitroanilino]-4-desoxypodophyllotoxin (4m)  
       [0098]     4β-Bromo-4-desoxypodophyllotoxin (0.1 g, 0.21 mmol) was reacted with 4-amino-3-nitro-benzophenone (0.056 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 8 h. After completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.4:0.6) as eluent.  
         [0099]     Yield 42%, mp 163-167° C.; [α] 25   D  −81 (c, 0.9, CHCl 3 )  
         [0100]      1 H NMR (200 MHz, CDCl 3 ): δ 8.68 (d, 1H), 8.50 (d, 1H), 8.05 (d, 1H), 7.75 (d, 2H), 7.55 (m, 3H), 6.93 (d, 1H) 6.750 (s, 1H), 6.58 (s, 1H) 6.50 (d, 1H), 6.32 (s, 2H), 6.00 (d, 2H), 5.32 (d, 1H), 5.07 (m, 1H), 4.68 (d, 1H), 4.35 (t, 1H), 3.92 (t, 1H), 3.80 (d, 9H), 3.13 (d, 1H) MS (m/e) 638 (M + , 15%), 582, 524, 428, 411, 383, 289.  
         [0101]     IR (KBr) cm −1 : 3400 (N—H), 2950 (aliphatic C—H), 1760 (lactone), 1640 (ketone), 1500, 1480, 1410, 1300, 1250 (aromatic C═C).  
       EXAMPLE 14  
     4′-O-Demethyl-4β-1″-[4″-(Benzoyl)]-2″-nitroanilino]-4-desoxypodophyllotoxin (4n)  
       [0102]     4β-Bromo-4′-O-demethyl-4-desoxypodophyllotoxin (0.1 g, 0.21 mmol) was reacted with 4-amino-3-nitrobenzophenone (0.056 g, 0.23 mmol) in presence of Et 3 N (0.032 g, 0.32 mmol) and Bu 4 N + I −  (0.015 g, 0.042 mmol) in dry tetrahydrofuran at room temperature for 8 h. After completion of reaction solvent was removed in vacuo. The residue was subjected to silica gel column chromatography using chloroform-methanol (9.6:0.4) as eluent.  
         [0103]     Yield 34%, mp 170-175° C.; [α] 25   D  −85 (c, 1.0, CHCl 3 )  
         [0104]      1 H NMR (200 MHz, CDCl 3 ): δ 8.70 (d, 1H), 8.50 (d, 1H), 8.10 (d, 1H), 7.75 (m, 3H), 6.93 (d, 1H), 6.72 (s, 1H) 6.58 (s, 1H), 6.32 (s, 2H), 6.00 (d, 2H), 5.40 (s, 1H), 5.05 (m, 1H), 4.65 (d, 1H), 4.35 (t, 2H), 3.90 (t, 1H), 3.80 (s, 6H), 3.10 (d, 2H)  
         [0105]     MS (m/e) 624 (M + , 15%), 467, 401, 229, 185  
         [0106]     IR (KBr) cm −1 : 3530 (O—H), 3450 (N—H) 2900 (aliphatic C—H), 1750 (lactone), 1650 (Ketone), 1500, 1480, 1410, 1250 (aromatic C═C).  
         [0107]     In conclusion, the main advantages of the present inventions are that these new 4β-1″-[2″-(substituted benzoyl)anilino] podophylotoxin analogues have exhibited promising in vitro cytotoxic activity and enhanced potential as anticancer agents. Further, these compounds have been prepared 4β-bromopodophylltoxin upon reaction with the corresponding 2-aminobenzophenone in the presence of Et 3 N and BU 4 N + I −  at room temperature to provide the 4β-1″-[2″-(substituted benzoyl)anilino]podophylotoxin analogues in very good yields and in almost stereoselective manner.