FIELD OF THE INVENTION

The present invention relates to N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides as cytotoxic agents. Particularly, the present invention relates to a process for the preparation thereof. More, particularly, present invention relates to N-((l-phenyl-9H-pyrido[3,4-b]indol-3- yl)methyl)cinnamamides of general formula A.

A

Ri = 3-F, 3,4,5-OMe, 4-OMe, H, 4-CF ₃ , 4-Cl, 4-OH-3-OMe, 3,4-CH ₂ -0-CH ₂ , 3,5-F, 4-OH, 1- napthyl, 9-phenanthryl, 4-Me,

R ₂ = 3,4,5-OMe, 3,4-Cl, 4-F, 3,5-F, 2,5-OMe, 4-Cl, 4-OH-3-OMe, 3-OH, 3,4,5-OH, 4-CF ₃ , 4- OMe, 4-NH _2.

BACKGROUND OF THE INVENTION β-Carbolines are of great interest due to their broad spectrum of biochemical effects and pharmaceutical functions (Allen, J. R.; Holmstedt, B. R. Phytochemistry 1979, 19, 1573). In particular, there have been intense research efforts in recent years in the design and development of β-carbolines as a new class of antitumor agents. β-Carbolines are initially discovered to exert their antitumor effects by intercalating into DNA. Subsequent investigations suggested that this class of compounds might exert their antitumor effects through multiple mechanisms of action, such as inhibiting topoisomerase I and II (Topo-I and II), cyclin-dependent kinase (CDK), mitogen activated protein kinase-activated protein kinase 2 (MK-2), kinesin-like protein Eg5 and I-Kappa-B kinase (IKK) (Rook, Y.; Schmidtke, K.; Gaube, F.; Schepmann, D.; Weunsch, B.; Heilmann, J.; Lehmann, J.; Winckler, T. . Med. Chem. 2010, 53, 3611). Further, the importance of β-carboline -based compounds is underscored by the fact that two of these, Tadalafil (Daugan, A.; Grondin, P.; Ruault, C; de Gouville, A. -C. L. M.; Coste, H.; Kirilovsky, J.; Hyafil, F.; Labaudiniere, R. . Med. Chem. 2003, 46, 4525) and Abecarnil (Turski, L.; Stephens, D. N.; Jensen, L. H.; Peterson, E. N.; Meldrum, B. S.; Patel, S.; Hansen, J. B.; Loscher, W.; Schneider, H. H.; Schmiechen, R. . Pharmacol. Exp. Ther. 1990, 253, 344) are clinically used for erectile dysfunction and CNS disorders, respectively.

During the last decade, natural products bearing the cinnamoyl moiety have attracted much attention due to their broad spectrum of biological activities and low toxicity. Additionally, irans-cinnamic acid derivatives, both isolated from plant sources or synthesized, are well-known for their antioxidant, antitumor, antimicrobial and antimycobacterial properties. Cinnamic acid derivatives, especially those combining the cinnamoyl moiety with hydroxyl groups' exluitrat free radical scavenging properties. Acids, esters, amides, hydrazides and related derivatives of cinnamic acid with such activities are reported in the literature for their health benefits (Leslie, B. J.; Holaday, C. R.; Nguyen, T.; Hergenrother, P. J. . Med. Chem. 2010, 53, 3964). OBJECTIVES OF THE INVENTION

The main object of the present invention is to provide novel N-((l-phenyl-9H-pyrido[3,4- b]indol-3-yl)methyl)cinnamamides la-1 to 13a-l as useful cytotoxic agents. Yet another object of this invention is to provide a process for the preparation of novel N-((l- phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides. SUMMARY OF THE INVENTION

Accordingly, present invention provides to N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl) cinnamamides general formul

A

Ri = 3-F, 3,4,5-OMe, 4-OMe, H, 4-CF ₃ , 4-Cl, 4-OH-3-OMe, 3,4-CH ₂ -0-CH ₂ , 3,5-F, 4-OH, 1- napthyl, 9-phenanthryl, 4-Me

R ₂ = 3,4,5-OMe, 3,4-Cl, 4-F, 3,5-F, 2,5-OMe, 4-Cl, 4-OH-3-OMe, H, 3,4,5-OH, 4-CF ₃ , 4-OMe, 4-NH ₂

In an embodiment of the present invention, chemical formulas of the representative compounds of formula la-1 to 13a-l are

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3,4,5- trimethoxyphenyl)acrylamide (la)

(E)-3-(3,4-dichlorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[ 3,4-b]indol-3- yl)methyl)acrylamide (lb)

(E)-3-(4-fluorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4- b]indol-3-yl)methyl)acrylamide (lc)

(E)-3-(3,5-difluorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[ 3,4-b]indol-3- yl)methyl)acrylamide (Id)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(3-fluorophenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (le)

(E)-3-(4-chlorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4- b]indol-3-yl)methyl)acrylamide (If)

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(4-hydroxy-3- methoxyphenyl)acrylamide (lg) (E)-N-((l-(3-fluorophenyl)-9H^yrido[3,4-b]indol-3-yl)methyl) -3-(3-hydroxyphenyl)acrylamide (lh)

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3,4,5- trihydroxyphenyl)acrylamide (li)

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(4- (trifluoromethyl)phenyl)acrylamide (lj)

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(4-methoxyphenyl)acrylamide (lk)

(E)-3-(4-aminophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b ]indol-3-yl)methyl)acrylamide (11)

(E)-3-(3,4,5-trimethoxyphenyl)-N-((l-(3,4,5-trimethoxyphenyl )-9H^yrido[3,4-b]indol-3- yl)methyl)acrylamide (2a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2b)

(E)-3-(4-fluorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H-pyr ido[3,4-b]indol-3- yl)methyl)acrylamide (2c)

(E)-3-(3,5-difluorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2d)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9 H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2e)

(E)-3-(4-chlorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H-pyr ido[3,4-b]indol-3- yl)methyl)acrylamide (2f)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(3,4,5-trimethoxyphe nyl)-9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2g)

(E)-3-(3-hydroxyphenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H-py rido[3,4-b]indol-3- yl)methyl)acrylamide (2h)

(E)-3-(3,4,5-trihydroxyphenyl)-N-((l-(3,4,5-trimethoxyphenyl )-9H^yrido[3,4-b]indol-3- yl)methyl)acrylamide (2i)

(E)-3-(4-(trifluoromethyl)phenyl)-N-((l-(3,4,5-trimethoxyphe nyl)-9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2j) (E)-3-(4-methoxyphenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H-py rido[3,4-b]indol-3- yl)methyl)acrylamide (2k)

(E)-3-(4-aminophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H-pyri do[3,4-b]indol-3- yl)methyl)acrylamide (21)

(E)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(3,4,5- trimethoxyphenyl)acrylamide (3a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (3b)

(E)-3-(4-fluorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4 -b]indol-3-yl)methyl)acrylamide (3c)

(E)-3-(3,5-difluorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (3d)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(4-methoxyphenyl)-9H-pyrid o[3,4-b]indol-3- yl)methyl)acrylamide (3e)

(E)-3-(4-chlorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4 -b]indol-3-yl)methyl)acrylamide (3f)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(4-methoxyphenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (3g)

(E)-3-(3-hydroxyphenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido[3, 4-b]indol-3- yl)methyl)acrylamide (3h)

(E)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(3,4,5- trihydroxyphenyl)acrylamide (3i)

(E)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(4- (trifluoromethyl)phenyl)acrylamide (3j)

(E)-3-(4-methoxyphenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido[3, 4-b]indol-3- yl)methyl)acrylamide (3k)

(E)-3-(4-aminophenyl)-N-((l-(4-methoxyphenyl)-9H^yrido[3,4-b ]indol-3-yl)methyl)acrylamide (31)

(E)-N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)-3-(3,4,5 -trimethoxyphenyl)acrylamide (4a)

(E)-3-(3,4-dichlorophenyl)-N-((l-phenyl-9H-pyrido[3,4-b]indo l-3-yl)methyl)acrylamide (4b) (E)-3-(4-fluorophenyl)-N-((l^henyl-9H^yrido[3,4-b]indol-3-yl )methyl)acrylamide (4c)

(E)-3-(3,5-difluorophenyl)-N-((l-phenyl-9H-pyrido[3,4-b]i ndol-3-yl)methyl)acrylamide (4d) (E)-3-(2,5-dimethoxyphenyl)-N-((l-phenyl-9H-pyrido[3,4-b]ind ol-3-yl)methyl)acrylamide (4e) (E)-3-(4-chlorophenyl)-N-((l-phenyl-9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (4f)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-phenyl-9H-pyrido[ 3,4-b]indol-3- yl)methyl)acrylamide (4g)

(E)-3-(3-hydroxyphenyl)-N-((l-phenyl-9H-pyrido[3,4-b]indol-3 -yl)methyl)acrylamide (4h)

(E)-N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)-3-(3, 4,5-trihydroxyphenyl)acrylamide

(4i);

(E)-N-((l^henyl-9H^yrido[3,4-b]indol-3-yl)methyl)-3-(4-(trif luoromethyl)phenyl)acrylamide (4j)

(E)-3-(4-methoxyphenyl)-N-((l-phenyl-9H-pyrido[3,4-b]indol-3 -yl)methyl)acrylamide (4k) (E)-3-(4-aminophenyl)-N-((l-phenyl-9H-pyrido[3,4-b]indol-3-y l)methyl)acrylamide (41)

(E)-N-((l-(4-(trifluoromethyl)phenyl)-9H-pyrido[3,4-b]ind ol-3-yl)methyl)-3-(3,4,5- trimethoxyphenyl)acrylamide (5a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(4-(trifluoromethyl)phenyl) -9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (5b)

(E)-3-(4-fluorophenyl)-N-((l-(4-(trifluoromethyl)phenyl)-9H- pyrido[3,4-b]indol-3- yl)methyl)acrylamide (5c)

(E)-3-(3,5-difluorophenyl)-N-((l-(4-(trifluoromethyl)phenyl) -9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (5d)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(4 trifluoromethyl)phenyl)-9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (5e)

(E)-3-(4-chlorophenyl)-N-((l-(4-(trifluoromethyl)phenyl)-9H- pyrido[3,4-b]indol-3- yl)methyl)acrylamide (5f)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(4-(trifluoromethyl) phenyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)acrylamide (5g)

(E)-3-(3-hydroxyphenyl)-N-((l-(4-(trifluoromethyl)phenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (5h)

(E)-N-((l-(4-(trifluoromethyl)phenyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)-3-(3,4,5- trihydroxyphenyl)acrylamide (5i) (E)-3-(4-(trifluoromethyl)phenyl)-N-((l-(4-(trifluoromethyl) phenyl)-9H^yrido[3,4-b]indol-3- yl)methyl)acrylamide (5j)

(E)-3-(4-methoxyphenyl)-N-((l-(4-(trifluoromethyl)phenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (5k)

(E)-3-(4-aminophenyl)-N-((l-(4-(trifluoromethyl)phenyl)-9H-p yrido[3,4-b]indol-3- yl)methyl)acrylamide (51)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3,4,5- trimethoxyphenyl)acrylamide (6a)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3,4- dichlorophenyl)acrylamide (6b)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(4-fluorophenyl)acrylamide (6c)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3,5- difluorophenyl)acrylamide (6d)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(2,5- dimethoxyphenyl)acrylamide (6e)

(E)-3-(4-chlorophenyl)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4- b]indol-3-yl)methyl)acrylamide (6f)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(4-hydroxy-3- methoxyphenyl)acrylamide (6g)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3-hydroxyphenyl)acrylamide (6h)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3,4,5- trihydroxyphenyl)acrylamide (6i)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(4- (trifluoromethyl)phenyl)acrylamide (6j)

(E)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(4-methoxyphenyl)acrylamide (6k)

(E)-3-(4-aminophenyl)-N-((l-(4-chlorophenyl)-9H-pyrido[3,4-b ]indol-3-yl)methyl)acrylamide (61) (E)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)-3-(3,4,5- trimethoxyphenyl)acrylamide (7a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(4-hydroxy-3-methoxyphenyl) -9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (7b)

(E)-3-(4-fluorophenyl)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H- pyrido[3,4-b]indol-3- yl)methyl)acrylamide (7c)

(E)-3-(3,5-difluorophenyl)-N-((l-(4-hydroxy-3-methoxyphenyl) -9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (7d)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(4-hydroxy-3-methoxyphenyl )-9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (7e)

(E)-3-(4-chlorophenyl)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H- pyrido[3,4-b]indol-3- yl)methyl)acrylamide (7f)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(4-hydroxy-3-methoxy phenyl)-9H-pyrido[3,4- b]indol-3-yl)methyl)acrylamide (7g)

(E)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)-3-(3- hydroxyphenyl)acrylamide (7h)

(E)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)-3-(3,4,5- trihydroxyphenyl)acrylamide (7i)

(E)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)-3-(4- (trifluoromethyl)phenyl)acrylamide (7j)

(E)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)-3-(4- methoxyphenyl)acrylamide (7k)

(E)-3-(4-aminophenyl)-N-((l-(4-hydroxy-3-methoxyphenyl)-9H-p yrido[3,4-b]indol-3- yl)methyl)acrylamide (71)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(3,4,5- trimethoxyphenyl)acrylamide (8a)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(3,4- dichlorophenyl)acrylamide (8b)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(4- fluorophenyl)acrylamide (8c) (E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(3,5- difluorophenyl)acrylamide (8d)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(2,5- dimethoxyphenyl)acrylamide (8e)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(4- chlorophenyl)acrylamide (8f)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(4-hydroxy-3 methoxyphenyl)acrylamide (8g)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(3- hydroxyphenyl)acrylamide (8h)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(3,4,5- trihydroxyphenyl)acrylamide (8i)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(4- (trifluoromethyl)phenyl)acrylamide (8j)

(E)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-pyrido[3,4-b]indol-3 -yl)methyl)-3-(4- methoxyphenyl)acrylamide (8k)

(E)-3-(4-aminophenyl)-N-((l-(benzo[d][l,3]dioxol-5-yl)-9H-py rido[3,4-b]indol-3- yl)methyl)acrylamide (81)

(E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(3,4,5- trimethoxyphenyl)acrylamide (9a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(3,5-difluorophenyl)-9H-pyr ido[3,4-b]indol-3- yl)methyl)acrylamide (9b)

(E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(4- fluorophenyl)acrylamide (9c)

(E)-3-(3,5-difluorophenyl)-N-((l-(3,5-difluorophenyl)-9H-pyr ido[3,4-b]indol-3- yl)methyl)acrylamide (9d)

(E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(2,5- dimethoxyphenyl)acrylamide (9e)

(E)-3-(4-chlorophenyl)-N-((l-(3,5-difluorophenyl)-9H-pyrido[ 3,4-b]indol-3- yl)methyl)acrylamide (9f) (E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(4-hydroxy-3- methoxyphenyl)acrylamide (9g)

(E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(3- hydroxyphenyl)acrylamide (9h)

(E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(3,4,5- trihydroxyphenyl)acrylamide (9i)

(E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(4- (trifluoromethyl)phenyl)acrylamide (9j)

(E)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)me thyl)-3-(4- methoxyphenyl)acrylamide (9k)

(E)-3-(4-aminophenyl)-N-((l-(3,5-difluorophenyl)-9H-pyrido[3 ,4-b]indol-3- yl)methyl)acrylamide (91)

(E)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(3,4,5- trimethoxyphenyl)acrylamide (10a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(4-hydroxyphenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (10b)

(E)-3-(4-fluorophenyl)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3,4 -b]indol-3-yl)methyl)acrylamide (10c)

(E)-3-(3,5-difluorophenyl)-N-((l-(4-hydroxyphenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (lOd)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(4-hydroxyphenyl)-9H-pyrid o[3,4-b]indol-3- yl)methyl)acrylamide (lOe)

(E)-3-(4-chlorophenyl)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3,4 -b]indol-3-yl)methyl)acrylamide (10f)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(4-hydroxyphenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (lOg)

(E)-3-(3-hydroxyphenyl)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3, 4-b]indol-3- yl)methyl)acrylamide (lOh)

(E)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(3,4,5- trihydroxyphenyl)acrylamide ( lOi) (E)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(4- (trifluoromethyl)phenyl)acrylamide (lOj)

(E)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(4- methoxyphenyl)acrylamide (10k)

(E)-3-(4-aminophenyl)-N-((l-(4-hydroxyphenyl)-9H-pyrido[3,4- b]indol-3-yl)methyl)acrylamide (101)

(E)-N-((l-(naphthalen-l-yl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(3,4,5- trimethoxyphenyl)acrylamide (11a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(naphthalen-l-yl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (lib)

(E)-3-(4-fluorophenyl)-N-((l-(naphthalen-l-yl)-9H-pyrido[3,4 -b]indol-3-yl)methyl)acrylamide (He)

(E)-3-(3,5-difluorophenyl)-N-((l-(naphthalen-l-yl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (lid)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(naphthalen-l-yl)-9H-pyrid o[3,4-b]indol-3- yl)methyl)acrylamide (lie)

(E)-3-(4-chlorophenyl)-N-((l-(naphthalen-l-yl)-9H-pyrido[3,4 -b]indol-3-yl)methyl)acrylamide (llf)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(naphthalen-l-yl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (llg)

(E)-3-(3-hydroxyphenyl)-N-(( 1 -(naphthalen- 1 -yl)-9H-pyrido[3 ,4-b]indol-3- yl)methyl)acrylamide (llh)

(E)-N-((l-(naphthalen-l-yl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(3,4,5- trihydroxyphenyl)acrylamide (Hi)

(E)-N-((l-(naphthalen-l-yl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(4- (trifluoromethyl)phenyl)acrylamide ( 1 lj)

(E)-3-(4-methoxyphenyl)-N-(( 1 -(naphthalen- 1 -yl)-9H-pyrido[3 ,4-b]indol-3- yl)methyl)acrylamide (Ilk)

(E)-3-(4-aminophenyl)-N-((l-(naphthalen-l-yl)-9H-pyrido[3,4- b]indol-3-yl)methyl)acrylamide (111) (E)-N-((l-(phenanthren-9-yl)-9H-pyrido[3,4-b]indol-3-yl)meth yl)-3-(3,4,5- trimethoxyphenyl)acrylamide (12a)

(E)-3-(3,4-dichlorophenyl)-N-((l-(phenanthren-9-yl)-9H-pyrid o[3,4-b]indol-3- yl)methyl)acrylamide (12b)

(E)-3-(4-fluorophenyl)-N-((l-(phenanthren-9-yl)-9H-pyrido[3, 4-b]indol-3-yl)methyl)acrylamide (12c)

(E)-3-(3,5-difluorophenyl)-N-((l-(phenanthren-9-yl)-9H-pyrid o[3,4-b]indol-3- yl)methyl)acrylamide (12d)

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(phenanthren-9-yl)-9H-pyri do[3,4-b]indol-3- yl)methyl)acrylamide (12e)

(E)-3-(4-chlorophenyl)-N-((l-(phenanthren-9-yl)-9H-pyrido[3, 4-b]indol-3-yl)methyl)acrylamide (12f)

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(phenanthren-9-yl)-9 H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (12g)

(E)-3-(3-hydroxyphenyl)-N-((l-(phenanthren-9-yl)-9H-pyrido[3 ,4-b]indol-3- yl)methyl)acrylamide (12h)

(E)-N-((l-(phenanthren-9-yl)-9H-pyrido[3,4-b]indol-3-yl)meth yl)-3-(3,4,5- trihydroxyphenyl)acrylamide ( 12i)

(E)-N-((l-(phenanthren-9-yl)-9H-pyrido[3,4-b]indol-3-yl)meth yl)-3-(4- (trifluoromethyl)phenyl)acrylamide (12j)

(E)-3-(4-methoxyphenyl)-N-((l-(phenanthren-9-yl)-9H-pyrido[3 ,4-b]indol-3- yl)methyl)acrylamide (12k)

(E)-3-(4-aminophenyl)-N-((l-(phenanthren-9-yl)-9H-pyrido[3,4 -b]indol-3-yl)methyl)acrylamide (121)

(E)-N-((l-(p-tolyl)-9H^yrido[3,4-b]indol-3-yl)methyl)-3-(3,4 ,5-trimethoxyphenyl)acrylamide (13a)

(E)-3-(3,4-dichlorophenyl)-N (l-(p-tolyl)-9H-pyrido[3,4-b]indol-3-yl)methyl)acrylamide (13b) (E)-3-(4-fluorophenyl)-N-((l-(p-tolyl)-9H-pyrido[3,4-b]indol -3-yl)methyl)acrylamide (13c) (E)-3-(3,5-difluorophenyl)-N-((l-(p olyl)-9H^yrido[3,4-b]indol-3-yl)methyl)acrylamide (13d) (E)-3-(2,5-dimethoxyphenyl)-N-((l-(p-tolyl)-9H-pyrido[3,4-b] indol-3-yl)methyl)acrylamide (13e) (E)-3-(4-chlorophenyl)-N-((l-(p-tolyl)-9H-pyrido[3,4-b]indol -3-yl)methyl)acrylamide (13f) (E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(p-tolyl)-9H-pyrido[ 3,4-b]indol-3- yl)methyl)acrylamide (13g)

(E)-3-(3-hydroxyphenyl)-N-((l-(p-tolyl)-9H^yrido[3,4-b]indol -3-yl)methyl)acrylamide (13h) (E)-N-((l-(p-tolyl)-9H^yrido[3,4-b]indol-3-yl)methyl)-3-(3,4 ,5-trihydroxyphenyl)acrylamide (13i)

(E)-N-((l-(p-tolyl)-9H^yrido[3,4-b]indol-3-yl)methyl)-3-(4-( trifluoromethyl)phenyl)acrylamide (13j)

(E)-3-(4-methoxyphenyl)-N-((l-(p-tolyl)-9H-pyrido[3,4-b]indo l-3-yl)methyl)acrylamide (13k) (E)-3-(4-aminophenyl)-N-((l-(p-tolyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)acrylamide (131)

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and appreciated.

In the present invention it is proposed to incorporate l-aryl-3-aminomethyl-P-carbolines with trans-cinnamic acids to provide N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides. The molecules comprising of l-aryl-3-aminomethyl-P-carboline and trans-cinnamic acid scaffolds within a single molecule could enhance the anticancer activity that might work through DNA intercalation.

The starting L-tryptophan (14), substituted benzaldehydes (16a-m) and substituted trans- cinnamic acids (22a-l) are commercially available and the N-((l-phenyl-9H-pyrido[3,4-b]indol- 3-yl)methyl) cinnamamides la-1 to 13a-l have been prepared as illustrated in the Scheme.1. i. the L-tryptophan methyl ester was prepared according to the following method. To the stirred solution of L-tryptophan (14, 0.1 mol) in methanol (50 ml), thionyl chloride (8.02 mL, 0.11 mol) was added drop-wise at 0 °C and continued stirring for 12 h at room temperature. The excess amount of solvent was removed under vacuum and dried well.

Then, the resulting solid was dissolved in CH ₂ CI ₂ , basified with saturated NaHC0 ₃ solution and extracted with excess amount of CH ₂ CI ₂ . Then, the organic layer was dried over anhydrous sodium sulphate and concentrated under reduced pressure to obtain L- tryptophan methyl ester (15) as white solid. ii. to the mixture of L-tryptophan ester (15, 0.023 mol) and appropriate benzaldeyde (16a- m, 0.023 mol) in ethanol (20 mL), catalytic amount of pTSA was added and the mixture was refluxed for 12 h. After completion of the reaction, ethanol was removed under vacuum and the obtained crude was dissolved in ethyl acetate (30 mL) and washed with saturated NaHC0 ₃ solution (20 mL) and water (20 mL). Then, the organic layer was dried over anhydrous sodium sulphate and concentrated under vacuum. Then, the resulting cyclic diastereomeric mixtures (17a— m) were used directly for next step without any further purification. iii. the suspension of compounds 17a-m (0.025 mol) and sulphur (0.075 mol) in xylene (50 mL) was refluxed for 8.0 h. The reaction mixture was cooled to room temperature, diluted with n-hexane and stood at 4.0 °C for 3.0 h. The resulted precipitate was filtered, washed with hexane, dried and the obtained solid was re-crystallised by using ethyl acetate to afford products 18a-m. iv. to a stirred suspension of compounds 18a-m (20 mmol) in dry THF (60 mL) was added LiBH ₄ (22 mmol) at 0 °C and stirred for 4 h at room temperature. After completion of the reaction, quenched with saturated NH ₄ CI solution (50 mL) and extracted with ethyl acetate (100 mL) and washed with water (50 mL). The organic layer was dried over anhydrous sodium sulphate, evaporated under reduced pressure and the crude products (19a-m) were used directly for the next step without any further purification. v. to a stirred solution of 19a-m (10 mmol) in dry THF (50 ml) was added DBU (15 mmol) and DPPA (12 mmol) at 0 °C. The reaction mixture was stirred for 16 h at rt and the reaction mixture was quenched with water, extracted with ethyl acetate and washed with water. The combined organic phases were dried over sodium sulphate, concentrated under reduced pressure and purified by column chromatography using silica gel to get pure compounds 20a-m. vi. to a stirred solution of azide compounds 20a-m ( 1 mmol) in acetonitrile and water (1: 1, 40 mL)) was added tripthenylphosphene (1.1 mmol) and stirred for 12 h at rt. The solvent was removed in vacuo, added 6N HC1 solution and washed with ethyl acetate (2 x 20 mL) and the aqueous acidic medium and basified with 20% NaOH solution (up to pH=10), extracted with chloroform, washed with water, dried over sodium sulphate and concentrated under reduced pressure to get crude products which were triturated in 10% ethyl acetate/ hexane, decanted and dried to get pure amine products (21a-m). vii. to a stirred solution of required amines (21a-m, 1 mmol)) and appropriate cinnamic acids (22a-l, 1.1 mmol) in DCM (10 mL) was added HBTU (1.3 mmol), TEA (3 mmol) and stirred for 12 h. After completion of the reaction quenched with ice cold water (20 mL), extracted with DCM (2 x 20 mL), washed with water (20 mL), dried over sodium sulphate and concentrated in vacuo. The crude products were purified by column chromatography using ethyl acetate and n-hexane as eluting solvents to get pure products N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides la-1 to 13a-l.

All the new N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides were synthesized and purified by column chromatography using different solvents like ethyl acetate and hexane. i. These new N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides have shown promising anticancer activity in various cancer cell lines.

Scheme 1. Synthesis of N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides. The structural formulae of the representative compounds are:

EXAMPLES

The following examples are given by way of illustration of the working of the invention practice and therefore should not be construed to limit the scope of present invention.

Example 1

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3,4,5- trimethoxyphenyl)acrylamide (la). To a solution of (l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(3,4,5-trimethoxyphenyl)acrylic acid (22a, 81 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to room 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-25%), collected fractions and evaporated in vacuo to afford la as yellow solid 149 mg (85% yield); mp: 148-150 °C; 1H NMR (300 MHz, CDCI ₃ + DMSO-de): δ (ppm) 10.90 (s, 1H), 8.15-8.08 (m, 1H), 8.02-7.77 (m, 4H), 7.65-7.43 (m, 4H), 7.29-7.16 (m, 2H), 6.80 (s, 2H), 6.64 (d, = 15.6 Hz, 1H), 4.88 (d, = 5.4 Hz, 2H), 3.89 (s, 6H), 3.84 (s, 3H); ¹³ C NMR (125 MHz, CDC1 ₃ + DMSO-d ₆ ): δ (ppm): 165.66, 163.84, 161.90, 153.49, 147.47, 142.07, 140.99, 140.00, 139.51, 139.11, 132.55, 131.09, 130.90, 128.71, 124.92, 122.06, 121.93, 121.15, 119.97, 115.79, 112.86, 112.23, 107.96, 105.37, 60.52, 56.29, 45.27; MS-ESI: m/z 512 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃₀ H ₂₇ O ₄ N ₃ F m/z 512.19618 [M + H] ⁺ ; found 512.19801.

Example 2

(E)-3-(3,4-dichlorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[ 3,4-b]indol-3- yl)methyl)acrylamide (lb). To a solution of (l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(3,4-dichlorophenyl)acrylic acid (22b, 74 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-20%), collected fractions and evaporated in vacuo to afford lb as yellow solid 118 mg (70% yield); mp: 255-258 °C; 1H NMR (500 MHz, DMSO-de) δ (ppm): 11.56 (s, 0.7H), 8.76 (s, 1H), 8.26 (d, = 7.6 Hz, 0.7H), 8.10 (s, 0.7H), 7.94-7.81 (m, 3H), 7.70-7.62 (m, 3H), 7.61-7.53 (m, 2H), 7.49 (d, = 15.8 Hz, 1H), 7.40-7.34 (m, 1H), 7.25 (t, = 7.0 Hz, 1H), 6.89 (d, = 15.7 Hz, 1H), 4.72 (s, 2H), peaks at 11.70, 8.43 and 8.17 are due to the 30% minor rotamer; ¹³ C NMR (125 MHz, DMSO-d ₆ ) δ (ppm): 141.0, 140.9, 136.7, 136.4, 133.0, 132.5, 131.1, 132.0, 131.5, 130.9, 129.9, 128.8, 127.7, 125.0, 124.9, 124.3, 122.4, 122.1, 121.7, 121.1, 120.0, 115.6, 115.4, 114.5, 112.9, 112.4, 45.2; MS-ESI: m/z 490 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₇ H ₁₉ FN ₃ O ₂ CI ₂ m/z 490.08687 [M+H ] ⁺ ; found 490.08731.

Example 3

(E)-3-(4-fluorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4- b]indol-3- yl)methyl)acrylamide (lc).

To a solution of (l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(4-fluorophenyl)acrylic acid (22c, 57 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-30%), collected fractions and evaporated in vacuo to afford lc as pale yellow solid 109 mg (73% yield); mp: 258-264 °C 1H NMR (500 MHz, DMSO-de) δ (ppm): 11.56 (s, 0.7H), 8.74 (s, 1H), 8.27 (d, = 7.7 Hz, 0.7H), 8.10 (s, .07H), 7.94-7.88 (m, 1H), 7.87-7.82 (m, 1H), 7.69-7.62 (m, 4H), 7.58-7.49 (m, 2H), 7.39-7.34 (m, 1H), 7.29-7.23 (m, 3H), 6.77 (d, = 15.7 Hz, 1H), 4.72 (d, = 4.8 Hz, 2H), peaks at 11.70, 8.44 and 8.16 are due to 30% minor rotamer; ¹³ C NMR (125 MHz, DMSO-d ₆ ) δ (ppm): 165.4, 164.1, 163.8, 162.1, 161.9, 147.4, 142.0, 140.0, 138.1, 131.1, 130.9, 130.1, 130.2, 128.8, 124.9, 122.6, 122.1, 121.8, 115.6, 114.4, 112.9, 112.7, 112.4, 45.2; MS-ESI: m/z 440 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₇ H ₂₀ ON ₃ F ₂ m/z 440.15474 [M + H] ⁺ ; found 440.15690. Example 4 (E)-3-(3,5-difluorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[ 3,4-b]indol-3- yl)methyl)acrylamide (Id).

To a solution of (l-(3-fluorophenyl)-9H^yrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(3,5-difluorophenyl)acrylic acid (22d, 63 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-20%), collected fractions and evaporated in vacuo to afford Id as yellow solid 117 mg (75% yield); mp: 215-220 °C 1H NMR (300 MHz, DMSO-de + CDCI3) δ (ppm): 10.95 (s, 0.7H), 8.30 (t, = 5.3 Hz, 1H), 8.14-8.05 (m, 1H), 7.99 (s, 1H), 7.96-7.75 (m, 3H), 7.65-7.43 (m, 3H), 7.28-7.15 (m, 2H), 7.06 (d, = 6.4 Hz, 2H), 6.84-6.75 (m, 2H), 4.87 (d, = 5.4 Hz, 2H), peak at 11.15 is due to the 30% minor rotamer; ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ): 164.5, 163.8, 163.6, 160.4, 145.4, 141, 139.3, 137.8, 136.6, 131.8, 130.1, 129.4, 127.5, 123.7, 120.6, 120.3, 120, 118.8, 114.8, 114.5, 114.2, 111.5, 109.3, 103.8, 103.5, 103.1, 44.5; MS-ESI: m z 458 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₇ H ₁₉ ON ₃ F ₃ m/z 458.14559 [M + H] ⁺ ; found 458.14747.

Example 5

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(3-fluorophenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (le).

To a solution of (l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(2,5-dimethoxyphenyl)acrylic acid (22e, 71 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-22%), collected fractions and evaporated in vacuo to afford le as yellow solid 130 mg (79% yield); mp: 228-230 °C 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.87 (s, 0.8H), 8.10 (d, = 7.7 Hz, 1H), 800-7.78 (m, 5H), 7.65-7.42 (m, 3H), 7.28-7.15 (m, 2H), 7.07 (s, 1H), 6.86 (s, 2H), 6.75 (d, = 15.7 Hz, 1H), 4.88 (d, = 5.4 Hz, 2H), 3.83 (s, 3H), 3.78 (s, 3H), peaks at 11.08 and 8.06 are due to the 20% minor rotamer; ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 164.8, 163.0, 152, 150.9, 145.9, 145.5, 140.5, 138,133.2, 131.2, 129.5, 129.0, 128.9, 126.8, 123.1, 121.3, 120.0, 119.7, 118.2, 114.3, 113.9, 113.6, 111.6, 111.1, 110.6, 54.7, 54.2, 43.9; MS-ESI: m/z 482 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₉ H ₂₅ O ₃ N ₃ F m/z 482.18536 [M + H] ⁺ ; found 482.18504.

Example 6

(E)-3-(4-chlorophenyl)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4- b]indol-3- yl)methyl)acrylamide (If).

To a solution of (l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(4-chlorophenyl)acrylic acid (22f, 62 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-20%), collected fractions and evaporated in vacuo to afford If as yellow solid 117 mg (75% yield); mp: 248-250 °C; 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 11.02 (s, 1H), 8.33-8.20 (m, 1H), 8.14-8.06 (m, 1H), 8.02-7.94 (m, 1H), 7.93-7.77 (m, 2H), 7.66-7.45 (m, 6H), 7.34 (d, = 8.3 Hz, 2H), 7.27-7.15 (m, 2H), 6.74 (d, = 15.6 Hz, 1H), 4.86 (d, = 5.2 Hz, 2H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 163.7, 159.4, 145.2, 140.2, 139.2, 136.2, 132.7, 132.2, 130.8, 129.1, 128.6, 127.4, 127.2, 126.5, 122.6, 121.2, 119.7, 119.3, 113.9, 113.4, 113.6, 112.2, 110.8, 110.2, 43.5; MS-ESI: m z 456 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₇ H ₂₀ ON ₃ CIF m/z 456.12541 [M + H] ⁺ ; found 456.12734.

Example 7

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)met hyl)-3-(4-hydroxy-3- methoxyphenyl)acrylamide (lg).

To a solution of (l-(3-fluorophenyl)-9H^yrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(4-hydroxy-3-methoxyphenyl)acrylic acid (22g, 66 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-35%), collected fractions and evaporated in vacuo to afford lg as yellow solid 109 mg (68% yield); mp: 205-210 °C; ^X H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.80 (s, 1H), 8.19-8.04 (m, 1H), 8.03-7.93 (m, 1H), 7.92-7.73 (m, 3H), 7.65-7.48 (m, 5H), 7.31-7.14 (m, 2H), 7.08-6.98 (m, 1H), 6.91-6.83 (m, 1H), 6.52 (d, = 15.6 Hz, 1H), 4.86 (s, 2H), 4.70 (s, 1H), 3.90 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDCI ₃ ) δ (ppm): 165.3, 147.2, 146.7, 145.7, 140.7, 139, 131.5, 129.8, 129.6, 129.3, 129.2, 127.1, 125.7, 123.3, 123.1, 120.8, 120.2, 118.4, 117.6, 114.5, 114.2, 113.9, 111.5, 111.3, 110.8, 109.3, 54.7, 44.1; MS-ESI: m/z 468 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃₀ H ₂₇ O ₄ N ₃ F m/z 468.16518 [M + H] ⁺ ; found 468.16801.

Example 8

(E)-N-((l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methyl )-3-(3- hydroxyphenyl)acrylamide (lh). To a solution of (l-(3-fluorophenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21a, 100 mg, 0.34 mmol) and (E)-3-(3-hydroxyphenyl)acrylic acid (22h, 56 mg, 0.34 mmol) in dry DMF (10 mL) was added HBTU (156 mg, 0.41 mmol) and triethylamine (0.14 mL, 1.03 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-30%), collected fractions and evaporated in vacuo to afford lh as yellow solid 97 mg (65% yield); mp: 142-148 °C; 1H NMR (300 MHz, DMSO-de + CDCI3) δ (ppm): 11.01 (s, 1H), 8.29-8.19 (m, 1H), 8.16-8.05 (m, 1H), 8.01-7.94 (m, 1H), 7.92-7.77 (m, 2H), 7.66-7.48 (m, 3H), 7.29-7.13 (m, 4H), 7.07-6.96 (m, 2H), 6.89 (d, = 8.8 Hz, 1H), 6.69 (d, = 15.6 Hz, 1H), 4.86 (d, = 5.0 Hz, 2H), 4.69 (s, 1H); ¹³ C NMR (75 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 165.2, 156.9, 145.7, 142.8, 140.9, 139.1, 135.4, 131.7, 130, 129.7, 128.7, 127.3, 123.5, 120.4, 119.9, 118.6, 118.1, 115.9, 114.7, 114.4, 114.1, 113.3, 112.7, 111.4, 111.1, 111.7, 44.3; MS-ESI: m/z 438 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₇ H ₂ iN ₃ 0 ₂ F m/z 438.15969 [M + H] ⁺ ; found 438.16123

Example 9

(E)-3 3,4,5-trimethoxyphenyl)-N^(l-(3,4,5-trimethoxyphenyl)-9H-pyr ido[3,4-b]indol-3- yl)methyl)acrylamide (2a).

To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(3,4,5-trimethoxyphenyl)acrylic acid (22a, 65 mg, 0.27 mmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triethylamine (0.11 mL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-30%), collected fractions and evaporated in vacuo to afford 2a as yellow solid 131 mg (82% yield); 165-170 °C 1H NMR (500 MHz, CDC1 ₃ ) δ (ppm): 8.54 (bs, 1H), 8.16 (d, = 7.7 Hz, 1H), 7.98 (s, 1H), 7.63-7.50 (m, 3H), 7.32 (t, / = 7.1 Hz, 1H), 7.14 (s, 2H), 6.94 (s, 1H), 6.74 (s, 2H), 6.44 (d, = 15.5 Hz, 1H), 4.92 (d, = 5.1 Hz, 2H), 3.96 (s, 6H), 3.95 (s, 3H), 3.88 (s, 6H), 3.87 (s, 3H), peaks at 8.04, 7.48, 4.02 and 4.00 are due to 10% minor rotamer; ¹³ C NMR (125 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 164.9, 160.1, 152.1, 145.6, 140.8, 138.8, 131.6, 129.8, 129.3, 129.2, 127.3, 127.2, 123.4, 120.3, 120.2, 120.2, 118.5, 114.3, 114.0, 112.6, 111.4, 111.0, 103.9, 59.6, 55.0, 44.2; MS-ESI: m/z 584 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃₃ H ₃₄ 0 ₇ N ₃ m/z 584.23803 [M + H] ⁺ ; found 584.23913.

Example 10

(E)-3-(3,4-dichlorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2b).

To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(3,4-dichlorophenyl)acrylic acid (22b, 59 mg, 0.27 mmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triethylamine (0.11 iriL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-28%), collected fractions and evaporated in vacuo to afford 2b as yellow solid 130 mg (84% yield); 165-170 ⁰ C 1H NMR (300 MHz, DMSO-de + CDC1 ₃ ) δ (ppm): 11.0 (s, 1H), 8.17-8.0 (m, 2H), 7.96 (s, 1H), 7.65-7.57 (m, 3H), 7.55-7.44 (m, 4H), 7.41-7.36 (m, 1H), 7.27-7.19 (t, = 7.9 Hz, 1H), 6.76 (d, = 15.6 Hz, 1H), 4.89 (d, = 5.4 Hz, 2H), 4.01 (s, 6H), 3.92 (m, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 164.1, 152.0, 145.1, 140.6, 136.9, 138.1, 136.0, 135.7, 134.4, 133.4, 132.9, 131.3, 129.5, 129.3, 127.9, 126.8, 125.8, 122.9, 120.1, 119.9, 118.2, 111.2, 110.0, 104.8, 59.4, 54.9, 44.0; MS- ESI: m/z 562 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃₀ H26O ₄ N ₃ Cl ₂ m/z 562.12828 [M + H] ⁺ ; found 562.12949. Example 11 (E)-3-(4-fluorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H-pyr ido[3,4-b]indol-3- yl)methyl)acrylamide (2c).

To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(4-fluorophenyl)acrylic acid (22c, 45 mg, 0.27 rnmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triefhylamine (0.11 mL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-22%), collected fractions and evaporated in vacuo to afford 2c as yellow solid 123 mg (88% yield); mp: 214-218 °C; 1H NMR (300 MHz, DMSO-de + CDCI3) δ (ppm): 10.99 (s, 1H), 8.11 (d, = 7.7 Hz, 1H), 8.01 (t, = 7.3 Hz, 1H), 7.97 (s, 1H), 7.67-7.45 (m, 6H), 7.28-7.20 (m, 2H), 7.07 (t, = 8.6 Hz, 2H), 6.65 (d, J = 15.6 Hz, 1H), 4.89 (d, = 5.4 Hz, 2H), 4.00 (s, 6H), 3.92 (s, 3H); ¹³ C NMR : 165.3, 164.1, 160.8, 152.7, 145.5, 141.3, 141.1, 138.7, 137.5, 133.4, 132.0, 130.7, 130.0, 128.7, 127.5, 120.7, 118.8, 114.9, 111.7, 110.8, 105.2, 120.5, 60.0, 55.5, 44.5; MS-ESI: m/z 512 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃ oH ₂₇ 0 ₄ N ₃ F »i/z 512.19610 [M + H] ⁺ ; found 512.19801.

Example 12

(E)-3-(3,5-difluorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H -pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2d). To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(3,5-difluorophenyl)acrylic acid (22d, 50 mg, 0.27 mmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triethylamine (0.11 mL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-25%), collected fractions and evaporated in vacuo to afford 2d as yellow solid 113 mg (78% yield); mp: 228-230 °C; 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.68 (s, 1H), 8.12 (d, = 7.7 Hz, 1H), 7.96 (s, 1H), 7.80 (t, =4.9 Hz, 1H), 7.64-7.48 (m, 3H), 7.40 (s, 2H), 7.25 (t, = 6.6 Hz, 1H), 7.04 (d, = 6.4 Hz, 2H), 6.84-6.75 (m, 1H), 6.68 (d, = 15.6 Hz, 1H), 4.91 (d, = 5.4 Hz, 2H), 4.00 (s, 6H), 3.94 (s, 3H); ¹³ C NMR (125 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 165.3, 164.1, 162.0, 146.1, 141.8, 138.7,

138.2, 137.5, 134.2, 132.7, 130.6, 128.1, 124.6, 121.4, 121.2, 119.5, 112.4, 110.4, 110.2, 105.9,

104.3, 60.8, 56.2, 45.3, 40.2; MS-ESI: m z 530 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃₀ H ₂₆ O ₄ N ₃ F ₂ m/z 530.18649 [M + H] ⁺ ; found 530.18859.

Example 13

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9 H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2e).

To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(2,5-dimethoxyphenyl)acrylic acid (22e, 57 mg, 0.27 mmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triethylamine (0.11 iriL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-28%), collected fractions and evaporated in vacuo to afford 2e as yellow solid 123 mg (81% yield); mp: 148-150 °C; 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.66 (s, 1H), 8.13 (d, = 7.9 Hz, 1H), 7.98 (s, 1H), 7.90 (d, = 15.8 Hz, 1H), 7.63-7.42 (m, 3H), 7.29-7.22 (m, 3H), 7.05 (s, 1H), 6.86 (s, 2H), 6.69 (d, = 15.8 Hz, 1H), 4.90 (d, = 5.2 Hz, 2H), 4.00 (s, 6H), 3.93 (3H), 3.83 (s, 3H), 3.78 (s, 3H); ¹³ C NMR (75 MHz, DMSO-de + CDC1 ₃ ) δ (ppm): 165.5, 158.5, 152.4, 151.4, 145.3, 141.0, 140.6, 137.2, 134.1, 133.0, 131.7, 129.8, 127.3, 123.6, 121.6, 120.5, 120.2, 118.6, 114.8, 114.4, 112.3, 111.5, 110.5, 105, 59.8, 55.2, 54.7, 44.1 ; MS-ESI: m/z 554 [M + H] ; HRMS (ESI): calcd for C32H32O6N3 m/z 554.22685 [M + H] ⁺ ; found 554.22856.

Example 14

(E)-3-(4-chlorophenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H- pyrido[3,4-b]indol-3- yl)methyl)acrylamide (2f).

To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(4-chlorophenyl)acrylic acid (22f, 50 mg, 0.27 mmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triethylamine (0.11 mL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-22%), collected fractions and evaporated in vacuo to afford 2f as yellow solid 116 mg (80% yield); mp: 148-150 °C; ^X H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 11.00 (s, 1H), 8.11 (d, J = 7.7 Hz, 1H), 8.08-8.01 (m, 1H), 7.97 (s, 1H), 7.66-7.57 (m, 2H), 7.56-7.45 (m, 3H), 7.34 (d, = 8.5 Hz, 2H), 7.30-7.20 (m, 3H), 6.71 (d, = 15.8 Hz, 1H), 4.89 (d, = 5.2 Hz, 2H), 4.00 (s, 6H), 3.92 (s, 3H); ¹³ C NMR (75 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 164.9, 152.4, 145.2, 141.0, 140.7, 137.5, 137.2, 137.0, 133.8, 133.0 132.8, 131.7, 129.7, 128.0, 127.3, 121.5, 120.5, 120.2, 118.6, 111.5, 110.5, 105.0, , 59.7, 55.2, 44.2; MS-ESI: m/z 528 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃₀ H ₂₇ O ₄ N ₃ CI m/z 528.16718 [M + H] ⁺ ; found 528.16846.

Example 15

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(3,4,5-trimethoxyphe nyl)-9H-pyrido[3,4-b]indol- 3-yl)methyl)acrylamide (2g). To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(4-hydroxy-3-methoxyphenyl)acrylic acid (22g, 53 mg, 0.27 mmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triethylamine (0.11 mL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-26%), collected fractions and evaporated in vacuo to afford 2g as yellow solid 109 mg (74% yield); mp: 175-178 °C; ^X H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.53 (s, 1H), 8.12 (d, = 7.7 Hz, 1H), 7.96 (s, 1H), 7.65-7.48 (m, 4H), 7.37 (s, 1H), 7.35 (m, 4H), 7.07-6.99 (m, 2H), 6.87 (d, = 8.6 Hz, 1H), 6.45 (d, = 15.4 Hz, 1H), 4.90 (s, 2H), 4.00 (s, 6H), 3.93 (s, 3H), 3.89 (s, 3H); ¹³ C NMR (75 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 166.6, 153.5, 148.5, 146.3, 142.0, 140.3, 138.2, 133.8, 133.8, 132.6, 128.3, 126.8, 122.0, 121.5, 121.1, 119.6, 118.6, 115.7, 112.5, 111.5, 110.5, 106.1, 60.7, 56.2, 55.9; MS-ESI: m/z 540 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃₁ H ₂₉ O ₆ N ₃ m/z 540.20564 [M + H] ⁺ ; found 540.21173.

Example 16

(E)-3-(3-hydroxyphenyl)-N-((l-(3,4,5-trimethoxyphenyl)-9H-py rido[3,4-b]indol-3- yl)methyl)acrylamide (2h).

To a solution of (l-(3,4,5-trimethoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)metha namine (21b, 100 mg, 0.27 mmol) and (E)-3-(3-hydroxyphenyl)acrylic acid (22h, 45 mg, 0.27 mmol) in dry DMF (10 mL) was added HBTU (125 mg, 0.33 mmol) and triethylamine (0.11 mL, 0.82 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-26%), collected fractions and evaporated in vacuo to afford 2h as yellow solid 98 mg (70% yield); mp: 175-178 °C; 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.79 (s, 1H), 8.12 (d, = 7.7 Hz, 1H), 7.96 (s, 1H), 7.71-7.58 (m, 3H), 7.57-7.40 (m, 4H), 7.30-7.14 (m, 4H), 7.11-6.96 (m, 2H), 6.84 (d, = 9.4 Hz, 1H), 6.61 (d, = 15.6 Hz, 1H), 4.90 (d, = 5.2 Hz, 2H), 4.71 (s, 1H), 4.00 (s, 6H), 3.92 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 165.0, 156.6, 152.2, 146, 145.4, 140.7, 138.9,

135.2, 133.1, 132.6, 131.5, 126.9, 129.4, 120.5, 120.3, 120.1, 118.3, 117.8, 115.7, 114.5, 113.1, 111.3, 110.1, 104.8, 59.5, 55.0, 44.1 ; MS-ESI: m/z 510 [M + H] ⁺ ; HRMS (ESI): calcd for

C ₃ oH ₂ 80 ₅ N ₃ [M + H] ⁺ 510.20051; found 510.20235.

Example 17

(E)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methy l)-3-(3,4,5- trimethoxyphenyl)acrylamide (3a).

To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(3-hydroxyphenyl)acrylic acid (22a, 78 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-20%), collected fractions and evaporated in vacuo to afford 3a as yellow solid 138 mg (80% yield); mp: 148-150 °C; 1H NMR (300 MHz, DMSO-de + CDC1 ₃ ) δ (ppm): 10.22 (s, 1H), 8.11 (d, = 7.7 Hz, 1H), 7.99 (d, = 8.7 Hz, 2H), 7.92 (s, 1H), 7.62-7.49 (m, 4H), 7.25 (t, 7 = 7.7 Hz, 1H), 7.12 (d, = 8.7 Hz, 2H), 6.76 (s, 2H), 6.55 (d, = 15.4 Hz, 1H), 4.89 (d, = 5.1 Hz, 2H), 3.90 (s, 3H), 3.88 (s, 6H), 3.86 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 165.2, 159.2, 152.4, 145.2, 140.8, 140.0, 139.2,

138.3, 131.7, 130.0, 129.8, 129.2, 127.4, 124.9, 120.6, 120.4, 120.3, 118.7, 113.4, 111.6, 110.4, 104.1, 55.9, 55.2, 54.6, 44.4; MS-ESI: m/z 516 [M + H] ⁺ ; HRMS (ESI): calcd for C ₃ iH ₃₀ O ₅ N ₃ m/z 524.21800 [M + H] ⁺ ; found 524.21613. Example 18 (E)-3-(3,4-dichlorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (3b).

To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(3,4-dichlorophenyl)acrylic acid (22b, 71 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-21%), collected fractions and evaporated in vacuo to afford 3b as yellow solid 137 mg (83% yield); mp: 188-190 °C; 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.01 (s, 1H), 8.11 (d, = 7.7 Hz, 1H), 8.02-7.71 (m, 4H), 7.63-7.48 (m, 4H), 7.47-7.25 (m, 3H), 7.1 1 (d, J = 8.4 Hz, 2H), 6.61 (d, = 15.6 Hz, 1H), 4.88 (d, = 4.9 Hz, 2H), 3.90 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 164.4,

159.1, 145.2, 141.3, 140.9, 136.4, 134.7, 133.3, 131.9, 131.8, 130.3, 129.9, 129.7, 128.3, 127.3,

126.2, 123.0, 120.6, 120.5, 118.7, 113.4, 111.5, 110.4, 110.1, 54.6, 44.6; MS-ESI: m z 502 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₈ H ₂₂ O ₂ N ₃ CI ₂ m/z 502.10836 [M + H] ⁺ ; found 502.10691.

Example 19

(E)-3-(4-fluorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4 -b]indol-3- yl)methyl)acrylamide (3c). To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(4-fluorophenyl)acrylic acid (22c, 54 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-24%), collected fractions and evaporated in vacuo to afford 3c as yellow solid 126 mg (85% yield); mp: 145-148 °C; 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.84 (s, 1H), 8.19 (t, = 5.0 Hz, 1H), 8.11 (d, = 7.9 Hz, 1H), 8.02 (d, = 8.5 Hz, 2H), 7.94 (s, 1H), 7.64-7.60 (m 2H), 7.58-7.47 (m, 3H), 7.23 (t, = 7.5 Hz, 1H), 7.15-7.03 (m, 4H), 6.67 (d, = 15.6 Hz, 1H), 4.85 (d, = 5.4 Hz, 2H), 3.92 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 163.8, 159.5, 158.1, 144.9, 140.0, 139.7, 136.3, 130.5., 129.8, 129.3, 128.5, 128.2, 127.8, 126.2, 120.3, 119.6, 119.3, 117.6, 113.9, 112.3, 110.8, 109.1, 53.6, 43.5; MS-ESI: m/z 452 [M + H] ⁺ ; HRMS (ESI); calcd for C ₂₈ H ₂₃ F 0 ₂ N ₃ m/z 451.16961 [M + H] ⁺ ; found 452.17471.

Example 20

(E)-3-(3,5-difluorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido [3,4-b]indol-3- yl)methyl)acrylamide (3d).

To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(3,5-difluorophenyl)acrylic acid (22d, 60 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-20%), collected fractions and evaporated in vacuo to afford 3d as yellow solid 136 mg (88% yield); mp: 230-232 °C; 1H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.92 (s, 1H), 8.43 (s, 1H), 8.11 (d, = 7.7 Hz, 1H), 8.02 (d, = 8.5 Hz, 2H), 7.93 (s, 1H), 7.62 (d, = 8.3 Hz, 1H), 7.50 (t, = 6.6 Hz, 2H), 7.23 (t, 7 = 7.5 Hz, 1H), 7.15-7.06 (m, 4H), 6.81 (d, = 15.4 Hz, 2H), 4.84 (d, = 5.4 Hz, 2H), 3.91 (s, 3H); ¹³ C NMR (75 MHz, DMSO-de + CDC1 ₃ ) δ (ppm): 164.8, 158.8, 145.1, 140.7, 136.2, 131.5, 130.1, 129.3, 128.9, 126.9, 123.7, 120.3, 120.2, 118.4, 113.1, 111.3, 110.0, 109.4, 109.2, 109.1, 103.2, 54.3, 44.3; MS-ESI: m/z 470 [M + H] ; HRMS (ESI); calcd for C ₂₈ H ₂₂ O ₂ N ₃ F ₂ m/z 470.16746 [M + H] ⁺ ; found 470.16570.

Example 21

(E)-3-(2,5-dimethoxyphenyl)-N-((l-(4-methoxyphenyl)-9H-py rido[3,4-b]indol-3- yl)methyl)acrylamide (3e).

To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(2,5-dimethoxyphenyl)acrylic acid (22e, 68 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-22%), collected fractions and evaporated in vacuo to afford 3e as yellow solid 146 mg (90% yield); mp: 130-135 °C; ^X H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.58 (s, 1H), 8.12 (d, = 7.7 Hz, 1H), 7.99 (d, = 8.7 Hz, 2H), 7.96 (s, 1H), 7.90 (d, = 15.8 Hz, 1H), 7.76 (t, = 5.3, 1H), 7.61 (d, = 8.3 Hz, 1H), 7.53 (t. = 6.9 Hz, 1H), 7.26 (t, = 7.5 Hz, 1H), 7.13 (d, = 8.8 Hz, 2H), 7.07 (s, 1H), 6.86 (s, 2H), 6.71 (d, = 15.8 Hz, 1H), 4.87 (d, = 5.4 Hz, 2H), 3.91 (s, 3H), 3.83 (s, 3H), 3.78 (s, 3H); ¹³ C NMR (75 MHz, DMSO-de + CDC1 ₃ ) δ (ppm): 166.1, 159.6, 152.8, 151.9, 144.9, 141.4, 140.8, 134.9, 131.9, 130.4, 129.5, 129.4, 127.9, 124.0, 121.6, 121.0, 120.6, 119.2, 115.3, 113.8, 112.9, 111.8, 111.9, 111.0, 55.5, 55.1, 54.8, 44.3; MS-ESI: m/z 494 [M + H] ⁺ ; HRMS (ESI): calcd for C30H28O4N3 m/z 494.20743 [M + H] ⁺ ; found 494.20549.

Example 22

(E)-3-(4-chlorophenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido[3,4 -b]indol-3- yl)methyl)acrylamide (3f). To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(4-chlorophenyl)acrylic acid (22f, 60 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-25%), collected fractions and evaporated in vacuo to afford 3f as yellow solid 127 mg (83% yield); mp: 140-145 °C 1H NMR (300 MHz, DMSO-de + CDC1 ₃ ) δ (ppm): 11.18 (s, 1H), 8.60 (t, = 5.4 Hz, 1H), 8.11 (d, = 7.9 Hz, 1H), 8.03 (d, = 8.7 Hz, 2H), 7.92 (d, = 3.2 Hz, 2H), 7.63 (d, = 8.3 Hz, 1H), 7.57 (m, 3H), 7.36 (d, = 8.5 Hz, 2H), 7.21 (t, = 7.4 Hz, 1H), 7.12 (d, = 8.8 Hz, 2H), 6.79 (d, = 15.8 Hz, 1H), 4.80 (d, = 5.6 Hz, 2H), 3.90 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 164.9, 159.4, 146.2, 141.3, 141.1, 137.5, 133.9, 133.5, 131.8, 130.6, 129.8, 129.5, 128.7, 128.5, 127.5, 122.6, 120.9, 120.7, 118.9, 113.6, 112.1, 110.4, 54.9, 4.8; MS-ESI: m/z 468 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₈ H ₂₃ O ₂ N ₃ CI m/z 468.14733 [M + H] ⁺ ; found 468.14598.

Example 23

(E)-3-(4-hydroxy-3-methoxyphenyl)-N-((l-(4-methoxyphenyl) -9H-pyrido[3,4-b]indol-3- yl)methyl)acrylamide (3g).

To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(4-hydroxy-3-methoxyphenyl)acrylic acid (22g, 64 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-30%), collected fractions and evaporated in vacuo to afford 3g as yellow solid 121 mg (77% yield); mp: 215-220 °C; ^X H NMR (300 MHz, DMSO-de + CDC1 ₃ ) δ (ppm): 10.53 (s, 1H), 8.09 (d, = 7.5 Hz, 1H), 8.00 (d, = 8.7 Hz, 2H), 7.94-7.87 (m, 2H), 7.74-7.45 (m, 4H), 7.28-7.17 (m, 1H), 7.21 (d, = 8.5 Hz, 2H), 7.06-6.98 (m, 1H), 6.86 (d, = 7.9 Hz, 1H), 6.50 (d, = 15.6 Hz, 1H), 4.86 (d, = 4.9 Hz, 2H), 4.65 (s, 1H), 3.90 (s, 3H), 3.89 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDC1 ₃ ) δ (ppm): 165.7, 159.2,

147.5, 146.9, 145.5, 140.9, 139.6, 131.8, 130.4, 129.7, 129.2, 128.9, 127.3, 126.2, 121.3, 120.7,

120.6, 118.7, 117.8, 113.5, 111.6, 110.4, 109.6, 55.1, 54.6, 44.5; MS-ESI: m/z 480 [M + H] ⁺ ; HRMS (ESI): calcd for C ₂₉ H ₂₆ O ₄ N ₃ m/z 480.19178 [M + H] ⁺ ; found 480.19010. Example 24

(E)-3-(3-hydroxyphenyl)-N-((l-(4-methoxyphenyl)-9H-pyrido[3, 4-b]indol-3- yl)methyl)acrylamide (3h).

To a solution of (l-(4-methoxyphenyl)-9H-pyrido[3,4-b]indol-3-yl)methanamine (21c, 100 mg, 0.33 mmol) and (E)-3-(3-hydroxyphenyl)acrylic acid (22h, 54 mg, 0.33 mmol) in dry DMF (10 mL) was added HBTU (150 mg, 0.39 mmol) and triethylamine (0.13 mL, 0.99 mmol) under nitrogen atmosphere and the reaction mixture was stirred at 35 °C for 12 h. After the complete consumption of starting materials (monitored by TLC), the contents of the reaction were cooled to 35 °C and poured into ice-cold water (25 mL), extracted by ethyl acetate (3 x 30 mL) and the combined organic phases were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The obtained residue was purified by column chromatography using ethyl acetate/n-hexane (0-30%), collected fractions and evaporated in vacuo to afford 3h as yellow solid 103 mg (70% yield); mp: 165-170 °C; ^X H NMR (300 MHz, DMSO-de + CDCI ₃ ) δ (ppm): 10.69 (s, 1H), 9.12 (bs, 1H), 8.10 (d, = 7.6 Hz, 1H), 8.04-7.92 (m, 4H), 7.64-7.48 (m, 5H), 7.28-7.07 (m, 3H), 7.02-6.97 (m, 2H), 6.83 (d, = 9.4 Hz, 1H), 6.64 (d, = 15.5 Hz, 1H), 4.86 (d, = 5.1 Hz, 2H), 3.90 (s, 3H); ¹³ C NMR (75 MHz, DMSO-d ₆ + CDCI ₃ ) δ (ppm): 165.2, 158.9, 156.7, 145.2, 140.9, 140.5, 139.1, 135.4, 131.5, 129.8, 129.6, 129.0, 128.7, 127.1, 120.5, 120.4, 120.2, 118.5, 118.0, 115.9, 113.3, 113.1, 111.4, 110.2, 54.4, 44.2; MS-ESI: m/z 450 [M + H] ⁺ ;HRMS (ESI); calcd for C ₂₈ H ₂₃ O ₃ N ₃ m/z 450.18122 [M + H] ⁺ ; found 450.17918. Biological Activity

Comparative cytotoxicity data of (l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methanamines and phenylcinnamides.

Table 1: The IC ₅₀ values ³ (in μΜ) for (l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methanamines 21b, 21c and 21e on selected cancer cell lines (A. Kamal et al. reported in Bioorg. Med. Chem. 2015, 23, 5511-5526).

50% Inhibitory concentration after 48 h of drug treatment and the values are average of three individual experiments, ^b lung cancer, ^c breast cancer, ^d cervical cancer.

Hergenrother and co-workers have synthesized phenylcinnamide derivatives and evaluated for their cytotoxic activity. Several new derivatives have shown cytotoxicity with IC ₅₀ values ranging from 1 to 10 μΜ (/. Med. Chem. 2010, 53, 3964).

The cytotoxic activity studies for these N-((l-phenyl-9H-pyrido[3,4-b]indol-3- yl)methyl)cinnamamides (la-h, 2a-h and 3a-h) were carried out in some representative human cancer cell lines. The cytotoxicity data revealed that these derivatives shows enhanced cytotoxicity (nM) than (l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methanamines and phenylcinnamide (μΜ).

Anticancer activity

The N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides (la-h, 2a-h and 3a-h) have been tested against five human cancer cell lines such as A549 (lung cancer), MCF-7 (breast cancer), B16 (melanoma), He La (cervical cancer) and NIH3T3 (mouse embryonic fibroblast cancer). All the cancer cell lines (HeLa, A549, MCF-7 and B 16) were procured from National Centre for Cell Sciences (NCCS, Pune, India) and NIH 3T3 cell line was obtained from American Type Culture Collection (Rockville, MD, USA). Stock cells were cultured in DMEM supplemented with 10% Fetal Bovine Serum (FBS), in an humidified atmosphere of 5% C0 ₂ at 37 °C until they are 80% confluent. To study the cytotoxicity of the compounds, after 80% confluence, cells were trypsinized with 0.1% trypsin-EDTA and harvested by centrifugation at 500 x g. Serial dilutions of cells were made from 1 x 10 ⁶ to 1 x 10 ³ cells per mL. The cells were seeded in triplicate in a 96 well plate. The cells were seeded in triplicate in a 96 well plate. The suspended cells were treated with 1, 3, 5, 10, 25, 50, 100, 500, 1000, 2000, 5000 and 10,000 nM of each compound (la-h, 2a-h and 3a-h) for 24 h duration. Since Doxorubicin was known as potential anticancer drug, the cells were treated with Doxorubicin, in the same concentration range was considered as control. The cell viability was determined by measuring the ability of cells to transform MTT to a purple coloured formazan dye. The absorbance of samples at 570 nm was measured using a UV- Visible spectrophotometer. Percentage of viable cells was calculated by using the formula given below.

OD ₅ -70 Sample

Percentage of cell viability = x lOO

OD ₅₇₀ Control

Where the OD ₅ -70 (sample) corresponds to absorbance obtained from the wells treated with compound and OD ₅ -70 (control) represents the absorbance from the wells in which no compound was added. For these compounds results are expressed as half maximal inhibitory concentration (IC ₅₀ ) values and the anticancer activity data of la-h, 2a-h and 3a-h are shown in Table 2. All the synthesized derivatives are very active than the precursor amines 21b, 21c and 21e (A. Kamal et al. Reported the IC ₅₀ values of 21b, 21c and 21e in Bioorg. Med. Chem. 2015, 23, 5511-5526, Table 1) and all the synthesized derivatives are significantly active against all the cell lines tested (IC ₅₀ = 13-45 nM) and compared with doxorubicin as control. However all the derivatives are very active than doxorubicin (>500 nM) and all the derivatives are active against MCF-7 cells (13-20 nM) than other cell lines. Moreover, the derivatives 3a, 3f and 3h are most active among these derivatives against MCF-7 cells (13.43, 14.05 and 13.84 nM respectively). Table 2: IC ₅₀ values ³ (in nM) for la-h to 3a-h on selected cancer cell lines. Compound

A549 ^b MCF-7 ^C B16 HeLa ^e NIH3T3 ^f la 17.92±0.6 16.23+1.5 19.76±0.6 22.98±0.7 35.98+1.3 lb 18.02±0.8 17.02+1.2 18.93±0.4 24.87±0.4 38.98+1.1 lc 16.33±0.3 16.46+1.8 16.84±0.8 24.32±0.6 30.77±2.1

Id 21.03+1.2 16.54±0.6 18.23±0.3 23.56±0.5 35.98±2.3 le 22.23+1.1 17.54±0.3 19.85±0.7 21.87±0.2 39.65+1.8

If 19.56+1.6 18.34±0.8 18.23+1.3 19.23±0.6 43.65+1.1 lg 22.42+1.1 17.93±0.7 19.45+1.1 23.85±0.4 36.86+1.9 lh 23.43±0.8 19.23±0.6 24.93±0.5 26.98±0.5 35.66±2.2

2a 21.34±0.9 16.54+1.1 17.23±0.4 23.48±0.3 38.87±2.5

2b 20.43±0.7 17.52+1.4 16.87±0.7 25.87±0.2 39.23+1.9

2c 18.74±0.7 16.37±0.8 17.25±0.3 19.98±0.5 42.98+1.1

2d 21.57+1.2 19.65+1.1 24.08±0.7 23.82±0.3 36.29+1.7

2e 18.77+1.4 17.23±0.6 19.23+1.4 25.09 ±0.2 38.97+1.9

2f 18.85+1.7 17.53±0.9 18.69+1.1 26.83±0.4 35.62±2.1

2g 18.26+1.4 17.55±0.7 19.04±0.9 25.98±0.3 43.08+1.3

2h 19.50+1.5 16.83±0.5 21.83±0.8 23.65±0.1 38.16+1.5

3a 19.69±0.6 I3,43±CL4 17.35±0.4 22.89±0.2 39.26+1.7

3b 18.43±0.7 16.43±0.5 22.98±0.5 21.65+0.4 37.45+1.4

3c 20.17+1.3 18.23±0.7 21.87±0.3 22.76±0.6 36.87+1.6

3d 19.97+1.1 17.23+1.2 23.87±0.2 24.65±0.4 37.54+1.3

3e 18.94+1.2 16.46±0.7 22.14±0.4 25.37±0.3 34.44+1.6

3f 18.89+1.1 14.05*0.9 16.64±0.5 21.55±0.6 38.31+1.3

3g 21.23+1.5 17.23±0.5 19.76±0.5 24.87±0.2 39.87+1.6

3h 18.86+1.4 13ϋ4±¾4 16.31+0.3 22.32±0.3 37.16+1.1

Doxorubicin 740±0.4 580±0.2 670±0.7 780±0.5 1720±0.8 ^d 50% Inhibitory concentration after 48 h of drug treatment and the values are average of three individual experiments, ^b lung cancer, ^c breast cancer, ^d melanoma, ^e cervical cancer/ mouse embryonic fibroblast cell line.

ADVANTAGES OF THE PRESENT INVENTION

• The present invention provides new N-((l-phenyl-9H-pyrido[3,4-b]indol-3- yl)methyl)cinnamamides are likely to be useful as anticancer agents and it also provides a process for the preparation of N-((l-phenyl-9H-pyrido[3,4-b]indol-3- yl)methyl)cinnamamides. The N-((l-phenyl-9H-pyrido[3,4-b]indol-3-yl)methyl)cinnamamides that have been synthesized and exhibited potent cytotoxic activity against different human tumor cell lines.