**3. Conclusion**

64 Chromatography and Its Applications

15

N

4

20

9

5 3

21

O

7

8 6

N

1

10

2

11

22

13

H-12/H-13 C-12/H-13, C-12/H-11

H-17/H-15 C-17/H-15

H-21/H-22 C-21/H-20, C-21/H-22

C-19/H-18, C-19/H-20

C-23,27/H-28,29

C-24,26/H-28,29 C-24,26/H-23,27

12

NH

<sup>N</sup> <sup>O</sup>

O

19

**11** 27.99 2.93(t,2H,J=7.2 Hz) 2 H-11/H-12 C-11/H-13, C-11/H-12

14.3 1.01(t,3H,J=7.6 Hz) 3 H-13/H-12 C-13/H-12, C-13/H-11 129.4 **---** -- C-14/H-18 131.1 8.81(d,1H, *Jm*=2 Hz) 1 H-15/H-17 C-15/H-17 121.2 **---** C-16/H-18

*Jm*=2 Hz) 1 H-17/H-18,

**<sup>19</sup>**159.7 **---** C-19/H-15, C-19/H-17

**20** 72.1 4.26(t,2H,J=7.2 Hz) 2 H-20/H-21 C-20/H-21, C20/H-22

**22** 10.85 1.19(t,3H,J= 7.6 Hz) 3 H-22/H-21 C-22/H-21, C-22/H-20

H-23,H-27 axial/ H-24,H-26

H-24,H-26/ H-23,H-27 axial H-24,H-26/ H-28,H-29

H-24,H-26 **---** 

2

**18** 113.2 7.16(d,1H,*Jo*=8.8 Hz) 1 H-18/H-17 **----** 

14

N

27

O

**<sup>12</sup>**22.5 1.84(m,2H,J=7.6 Hz) 2 H-12/H-11,

**<sup>21</sup>**22.54 2.05(m,2H,*J*=6.8 Hz) 2 H-21/H-20,

axial) <sup>1</sup>

**28,29** 19.5 1.05(d,6H,J=6.8 Hz) <sup>3</sup>H-28,H-29/

δ ppm in CDCl3, *J* in Hz a) Number in DEPT is the number of attached protons.

1.93(t,2H, *J*=10.4 Hz, axial) & 3.68(dd,2H, *J*=10.4 Hz, *J*=1.6 Hz equatorial)

**<sup>17</sup>**131.8 7.84(dd,1H,*Jo*=8.8 Hz,

**24,26** 50.5 3.03(m, 2H, *J*=3.6 Hz,

Table 3. NMR data of Dimethylhomosildenafil.

**23,27** 52.3

S

17 18

**No 13C 1H DEPTa COSY HMBC**  146.7 **---** C-3/H-12 C-3/H-11 147.2 **---** C-5/H-15 -- 10.84(br.s,1H) **---**  153.8 **--- ---**  124.7 **---** C-8/H-10 138.6 **---** C-9/H-11 38.4 4.27(s,3H) 3 **---** 

NH

25

H <sup>H</sup> <sup>3</sup>CH

<sup>23</sup> <sup>28</sup>

CH3

29

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