Synthesis and Antidepressant activity of 3, 4- dihydropyrimidin-2(1H)-ones
Bedis S. P., Garud A. A., Patil C. P.
Rasiklal M. Dhariwal, Institute of Pharmaceutical Research & Education Research,
Achary Anand Rishiji Marg, Chinchwad, Pune
*Corresponding Author E-mail: jitendra_rsu@yahoo.co.in
ABSTRACT:
Derivatives of 3, 4- dihydropyrimidin-2(1H)-one and2, 5dioxo,4-aryl octahydroquinazolines were synthesized by microwave irradiation. The synthesized derivatives were characterized for physicochemical parameters and the spectroscopic studies. Compounds were screened for its antidepressant activity by using Tail Suspension Test (TST) and Forced Swim Test (FST) using fluoxetine as the standard. The duration of immobility measured in the control and animal groups treated with standard antidepressant drug (fluoxetine) and test drugs exhibited decrease in the immobility in both the models significantly and was comparable to the standard. Derivatives produced significant antidepressant activity in both the FST and TST in dose dependant manner.
KEYWORDS: 3, 4- dihydropyrimidin, antidepressant activity, Biginelli synthesis, microwave irradiation Tail Suspension Test (TST) and Forced Swim Test (FST).
INTRODUCTION:
The biological etiology of depression is hypothesized to be due to a deficiency in monoaminergic neurotransmitters, and more specifically, deficiencies in norepinephrine (NE) and serotonin (5-hydroxytryptamine; 5-HT).
Antidepressant drugs targeted to inhibit 5-HT/NE reuptake transporters have been developed to treat major depression, especially in patients with pain and urinary incontinence.
Selective serotonin reuptake inhibitors (SSRIs) have improved safety and tolerability of antidepressant treatment.
However, compliance is often hampered by adverse drug effects, mainly during the initial phases of treatment.
The tail suspension test (TST) and forced swim test (FST) are commonly used screening methods for antidepressant activities of drugs in mice. These are simple screening tests for the behavioral effects of antidepressants in rodents. [2](4)(5)
Pyrimidines are an important class of nitrogen containing heterocycles with wide range of pharmacological and therapeutic properties like antiviral, antitumor, antibacterial and anti-inflammatory activities (tetra 2007). Recently they have emerged as calcium channel blockers [1], alpha antagonists and neuropeptide (NPY) antagonists [2]. Alkaloids containing the dihydropyrimidine core structure have been isolated from marine sources which demonstrate fascinating biological behavior [3]. Most notably among these are the betzelladine alkaloids, which found to be potent HIVgp-120- CD4 inhibitor, the anti-cancer agent Monastrol, has been shown to specifically affect mitosis via a new mechanism consisting of the specific and reversible inhibition of the motility of the motor protein, mitotic kinesin Eg5.(13,14) At the same time, (R)-SQ 32926 has been found to have potent anti-hypertensive activity.(15 ) Therefore the design of pyrimidinones for specific targets has gained lot of significance in medicinal chemistry.
The original Biginelli synthesis of substituted 3,4 dihydropyrimidin-2-(1H)one has undergone various modifications, with respect to the use of different substituted aldehydes, thiourea/urea and different 1,3 dicarbonyl compounds like ethylacetoacetate/dimedone to give dihydropyrimidin-2-(1H) one/octahydroquinazolines involving some Lewis acids and many other metal catalysts over the period of time. In recent years, several synthetic procedures for preparing of DHPMs have been reported including conventional stirring, microwave irradiation, ultrasound irradiation, and the use of ionic liquids as catalysts which have overcome the problems associated with the conventional synthesis. The present synthesis was catalyzed by sulfamic acid. In the solid state, the molecule of Sulfamic acid is well described as a zwitterionic form. As sulfamic acid is a non-volatile, inexpensive, and non-corrosive common inorganic acid, commercially available, it has emerged as a substitute for conventional acidic catalysts in different areas of organic synthesis with good yields
Synthesis:
Procedure:
A mixture of ethylacetoacetate (10 mmol) 3/dimedone (10mmol)5, urea 2(10mmol), various aldehydes1 (as mentioned in the table) (10 mmol), and sulfamic acid (1 mmol) as a catalyst were taken in two necked round bottomed flask. 1-2 ml of ethanol was added as per need.
The resulting mixture was well stirred and then subjected to microwave irradiation (Make-Raga’s Scientific) at 140W till the completion of the reaction. The reaction was monitored by TLC using mobile phase- [Ethyl acetate: Toluene (6:4)].
The content of the flask was cooled to room temperature and ice was added along with stirring. The obtained solid was washed with cold water, and recrystallized using ethanol to obtain the pure product.
The synthesized products were characterized by melting points and their spectral (UV, IR and 1H NMR) data.
Table No.1
|
|
|
R |
Reaction Time (Min) |
Yield (%)a |
Melting Point (0C)b |
λ max (nm)d |
|
1 |
4a |
C6H5 |
8.0 |
94.20 |
203-204 |
278.5 |
|
2 |
4b |
4-OH- C6H4 |
4.5 |
88.04 |
200-201 |
272.5 |
|
3 |
4c |
3-CH3O-4-OH- C6H3 |
5.5 |
86.09 |
235-237 |
304 |
|
4 |
4d |
4-Cl- C6H4 |
5 |
91.49 |
212-214 |
279 |
|
5 |
4e |
3-NO2-C6H4 |
3 |
89.26 |
231-233 |
278.5 |
|
6 |
4f |
2,5-CH3O- C6H3 |
10 |
75 |
208-209 |
287 |
|
7 |
4g |
3,4,5-CH3O-C6H2 |
10 |
68.57 |
165-167 |
282 |
|
8 |
4h |
4-F- C6H4 |
12 |
71.94 |
163-165 |
282 |
|
9 |
6a |
C6H5 |
6.5 |
92 |
138-140 |
224.5 |
|
10 |
6b |
4-OH- C6H4 |
8 |
85.40 |
265-275 |
248.5 |
|
11 |
6c |
3-CH3O-4-OH- C6H3 |
8.5 |
80 |
253-255 |
375.5 |
|
12 |
6d |
4-NO2- C6H4 |
7.0 |
74.32 |
230-235 |
374 |
|
13 |
6e |
2-OH-C6H4 |
10.0 |
74.38 |
240-245 |
282 |
a Recrystallization solvent-Ethanol
b Uncorrected melting points
c Mobile Phase [Ethyl acetate: Toluene (6:4)]
d Solvent-Ethanol
Experimental:
All the compounds were characterized by IR, 1H NMR Spectra. The IR spectra were obtained by using FTIR Spectrophotometer with Diffuse Reflectance attachment (Shimadzu 8400S). 1H NMR Spectra were obtained on NMR Spectrophotometer (University of Pune, Varian Mercury YH 300) and NMR Spectrophotometer (SAIF, Punjab University, Bruker Avance II 400 NMR) using CDCl3 and DMSO as solvent, chemical shifts are given in ppm. Melting Points were determined using Veego melting point apparatus (VMP PM, 32/1104) All the melting points are uncorrected.
1. 5-(ethoxycarbonyl)-6-methyl-4-phenyl- 3,4 dihydropyrimidin2(1H)- one
IR (vmax, KBr, cm-1) 3251, 3116 (-NH), 3031(Aromatic –CH)
2981(Aliphatic – CH), 1724(ester -C=O), 1647(-NHC=O), 1600 – 1473 (isolated - C = C), 1222 (Acetate –C=O), 1180-1091(– C – O – C), 775-702 (Aromatic –CH bending).
1H NMR (CDCl3) δ:
8.15 (s, 1H, NH), 7.26-7.32 (m, 5H, Ar-H), 5.7 (s, 1H, NH),
5.3(s, 1H, CH), 4.03(q, 2H, O- CH2), 2.34 (s, 3H, CH3), 1.16(t, 3H, OCH2CH3)
2. 5-(ethoxycarbonyl)-4(-4 hydroxy phenyl)-6 methyl- 3,4 dihydropyrimidin 2-(1H)- one
IR (vmax, KBr, cm-1) 3228(-OH stretch), 3116(-NH stretch), 3020 (Aromatic-C-H stretch),
1689(-C=O stretch), 1641 (IsolatedC=Cstretch), 1477 (Aromatic-C=Cstretch),
1384 (Ester C-O-C), 802 (Aromatic CH stretch)
1H NMR (CDCl3) δ:
9.08 (1H, OH), 8.9 (s, 1H, NH), 7.43 (s,1H,-NH ), 7.06 d,(2H,Aromatic), 6.67
(d, 2H, Aromatic), 5.13-5.14(s,1H,-CH), 3.98-4.03 (q, 2H, O- CH2), 2.27 (s, 3H, CH3), 1.1-
1.17 (t, 3H, OCH2CH3)
3. 5-(ethoxycarbonyl) -6methyl-4-(4-hydroxy, 3methoxy phenyl)-3,-4dihydropyrimidin
-2- (1H) one
IR (vmax, KBr, cm-1)3259,3359 (-OH),3255, 3112 (-NH), 2943( -C=C Aromatic ) , 1697,1703
C=O (ester), 1473( -C=C-Aromatic), 1218 ( -OCH3 Stretch) , 1172-1091 (Ester-C-O
Stretch), 802(Aromatic-CH bend
1H NMR (CDCl3) δ
: 8.94 (s, 1H, NH), 8 (1H,-OH). 7.38 (s, 1H, -NH), 6.74-6.83(3H, Aromatic multipletes 5.16
(s,1H, -CH), 4.02-4.05 (q,2H, -CH2 (ester)) 5.53 (s,1H, CH), 4.07-4.09 (q, 2H, O- CH2),
2.35 (s, 3H, CH3), 1.25(t, 3H, OCH2CH3)
4. Synthesis of 4-( 4-chloro phenyl)-5-ethoxycarbonyl)-6-methyl-3,4 dihydropyrimidin-
2(1H)-one
IR (vmax, KBr, cm-1)3251,3116(-NH stretch),2981(Arm-CH stretch),1647(isolated-C=C
stretch),1600-1465(Arm-C=C stretch),1380-1091(ester-C-O-C stretch),779-(Arm-CH bend)
1H NMR (CDCl3) δ:
8.18 (s,1H, -NH),7.19(Arm multiplates), 5.19(s,1H,NH), 5.37(-CH), 4.04(q), 2.33(s,3H,-
CH3),1.15 (t,3H ester, CH3)
5. 5 (ethoxyCarbonyl)-6 methyl-4-(3 nitro phenyl)- 3,4 dihydropyrimidin 2-(1H) one
IR(vmax, KBr, cm-1) 3255 ( - NH Stretch), 2966(- Aliph – CH Stretch)
1527, 1346 (- NO2), 1091(ester – C – O – C Stretch), 867, 775 (Arm – CH bend)
1H NMR (CDCl3) δ:
10(s1H, -NH), 8.2(Arm-multiplates), 5.6(s,1H, methine-CH), 4.2 (2H,-OCH2)
3.8 (s-CH2), 1.25(t,3H, ester CH3)
6. 5-(Ethoxy Carbonyl)-6-methyl-4-(2, 5 dimethoxyphenyl)-3, 4- dihydro pyrimidin-
2(1H)-one
IR(vmax, KBr, cm-1) 3247, 3112(-NH Stretch), 3049 (Aromatic – CH Stretch), 2981 (Aliphatic – CH Stretch), 1704( ester -C=O Stretch), 1643(-NHC=O Stretch),
1589-1496 (isolated C = C Stretch), 1230 (Acetate –C=O stretch), 1153-1087(– C – O – C
Stretch) 806-736 (Aromatic –CH bending)
1H NMR (DMSO) δ:
9.00 (s, -NH, 1H), 6.72- 6.85(Aromatic multiplets), 6.52 (s, -NH, 1H), 5.56 (s, methine –
CH,1H), 3.97-4.02(q, ester O- CH2 , 2H), 3.70( s , O-CH3 3H), 3.82(s , O-CH3 , 3H)
1.09-1.12 (t, ester CH3, 3H)
7. 5-(Ethoxy Carbonyl)-6-methyl-4-(3, 4, 5 trimethoxyphenyl)-3, 4- dihydro
pyrimidin-2(1H)-one
IR (vmax, KBr, cm-1) 3228, 3116(-NH Stretch), 3097 (Aromatic – CH Stretch), 2943 (Aliphatic
– CH Stretch) 1716 Ester (-C=O Stretch), 1654(-NHC=O Stretch), 1585-1504 (isolated - C = C
Stretch) 1230 (Acetate –C=O stretch), 1126-1095(– C – O – C Stretch), 844-732 (Aromatic – CH bending)
1H NMR (DMSO) δ:
9.02(s, -NH, 1H), 8.0 (s,-NH, 1H), 6.55- 7.28 (Aromatic multiplets), 5.20( s, methine –CH, 1H)
4.03-4.08 (q, ester O- CH2, 2H), 3.78 (s, O-CH3, 3H), 3.71 (s, O-CH3,6H), 2.29 (s, -CH3,3H) 1.16-1.20 (t, ester CH3, 3H)
8. 5-(Ethoxy Carbonyl)-6-methyl-4-(4-flurophenyl)-3, 4- dihydro pyrimidin-2(1H)- one
IR (vmax, KBr, cm-1) 3240, 3120(-NH Stretch), 3026 (Aromatic – CH Stretch)
2900-2981 (Aliphatic – CH Stretch), 1728 (ester -C=O Stretch), 1647(-NHC=O Stretch)
1589-1504 (isolated - C = C Stretch), 1222 (Acetate –C=O stretch), 1161-1095(– C – O – C
Stretch), 844-729 (Aromatic –CH bending)
1H NMR (DMSO) δ
9.08(s -NH, 1H), 7.58 (s, -NH, 1H), 6.98-7.58(Aromatic multiplets), 5.21(s, methine -CH, 1H )
3.98-4.04 (q, ester O- CH2, 2H), 2.28(s, -CH3, 3H), 1.12-1.15 (t, ester CH3, 3H)
9. 7, 7-dimethyl-4-phenyl-4, 6, 7, 8-tetrahydroquinazoline-2, 5 (1H,3H)-dione
IR (vmax, KBr, cm-1)
3211.26(-NH Stretch),3064.68(Arm.CH stretch),1643.24(NHC=O
Stretch),1697.24(C=O stretch),2956.67(dimethyl C-H stretch),
700.11(mono substituted aromatic ring)
1H NMR (DMSO) δ
8.70(-NH, s),8.10(NH),6.85-6.40(Arm multiplates), 4.56(s, C-4),1.80-2.30 (CH2 multiplates)
0.80-1.05(6Hdimethyl group))
10. 4-(4-hydroxyphenyl)-7, 7dimethyl-4,6,7,8- tetrahydroquinazoline-2,5(1H,3H)-dione
IR(vmax, KBr, cm-1)3195.76(NH-stretch),3062.75(Arm-CH stretch),1612.38(NHC=O
stretch), 2954.74(dimethyl C-H stretch),1174.78(P-OH group) 690.47(mono-substituted aromatic ring),
1H NMR (DMSO) δ
9.04(OH), 8.80(-NH,s), 8.13(NH), 6.88-6.46(Arm multiplates), 4.66(s,C-4),1.85-2.32(CH2
multiplates), 0.84-1.09(6Hdimethyl group))
11. 4-(4-hydroxy-3methoxyphenyl) - 7,7dimethyl-4,6,7,8- tetrahydroquinazoline-
2, 5(1H, 3H)-dione
IR(vmax, KBr, cm-1)3255.62(NH-stretch),3047.32-3168.83(Arm-CH stretch),
1625.88(NHC=O stretch), 2954.74(dimethyl C-H stretch),1141.78(P-OH group),1035.70(-
OCH3group) ,721(mono-substituted aromatic ring),
1H NMR (DMSO) δ
8.09((OH), 9.05(-NH,s), 8.36 (NH),6.77-6.56 (Arm multiplates), 4.77(s,C-4),3.72(OCH3)
2.29-2.43(CH2 multiplates), 0.93-0.97(6Hdimethyl group)
12. 7,7 dimethyl-4-(4-nitrophenyl)-4,6,7,8-tetrahydoquinazoline- 2,5 (1H,3H)-dione
IR (vmax, KBr, cm-1) 3213 (-NH), 3213 (Aromatic –CH) 2958.60{Dimethyl (C-H) stretch}
; 1697.24 (C=O Stretch); 1643.24 (NH-C=O Stretch); 1350 (NO2 Stretch); 829 (Aromatic
P-substituted CH bending); 698.18&725.18 (Mono-substituted aromatic ring)
1H NMR (CDCl3) δ
8.07 (s, 1H, NH), 7.2-6.96. (4H, Aromatic multiplates); 6.4 (s, 1H, NH), 5.4(s,1H,-CH
methine); 2.2-2.5 (4H, CH2), 1.1-1.2 ( s, 6H,dimethyl)
13. 4-(2-hydroxyphenyl)-7,7-dimethyl-4,6,7,8-terahydroquinazoline- 2,5(1H,3H)- dione.
IR (vmax, KBr, cm-1) 3280.83 (O-H Stretch); 3168 (NH Stretch) 2956.67{C-H Stretch (dimethyl)}, 1691.46 (C=O Stretch), 1643.24(NH-C=O Stretch),
657.68 (Mono-substituted aromatic ring)
1H NMR (CDCl3) δ:
10.43 (s, phenolic OH), 6.8-7.1(4H, Aromatic multipletes) 6.1 (s,-NH ), 5.0
(s,-CH) , 2.1-2.50(4H, -CH2 multipletes), 0.96-1.03 (6H, CH3 multipletes)
Pharmacology (Antidepressant activity):
Experimental Animals:
Swiss albino mice of either sex (20-30 gm) were obtained from Serum India Ltd, Pune. They were housed under standard condition of temperature 24±1OC, relative humidity (65±10%) and light and dark cycle (14:10 hrs). Animals were fed with standard pellets (Amrut feeds, Sangli) and provided with water ad libitum. Institutional Animal Ethics Committee approved experimental protocol :( IAEC Reg. o. DYPIPSR/IEAC/ 10-11 /P-29)
Acute Toxicity Study (OECD Guidelines-423, 2004):
Acute toxicity study for the test drugs are carried out in mice according to OECD guidelines. Test drugs were administered in a dose of 2000 mg/kg, p.o. and animals were observed individually and continuously for 30 min, 2 hr and 24 hr to detect changes in the autonomic or behavioral responses and also for tremors, convulsion, salivation, diarrhoea, lethargy, sleep and coma and then monitored for any mortality for the following 14 days. There was no toxic reaction or mortality observed, and the animals were found to be devoid of any toxicity.
Behavioral tests[3]
The tail Suspension Test (TST) and forced swim test (FST) are commonly used screening methods for antidepressant activities of drugs in mice. These are simple screening tests for the behavioral effects of antidepressants in rodents. The methods are based on the observation that if a mouse is placed in a stressful situation, such as suspension by the tail, forced to swim in a tank of deep water, from which it cannot escape, the mouse develops an immobile posture. The duration of immobility has been inferred to as an index of behavioral despair, where longer durations of immobility imply a greater degree of behavioral despair.
Albino mice of either sex weighing 20 – 30 g were selected and divided into three groups (n=6). All the animals of different groups were treated as follows.
RESULTS:
One way ANOVA followed by Dunnett’s test was applied for statistical analysis p<0.01**, p<0.05* when compared with the control group.
Effect of synthesized dihydropyrimidine derivatives on tail suspension induced immobility in mice
Fig No.1
Effect of synthesized dihydropyrimidinone derivatives on forced swim induced immobility in mice
Fig No2
DISCUSSION:
Synthesized dihydropyrimidinone derivatives were screened for Antidepressant activity. Both forced swim and tail suspension tests are the accepted stress models of depression. Immobility has been shown to reflect a state of ‘behavioral despair and variants’ or ‘failure to adapt to stress’. Immobility displayed in both of these behavioral despair models has been hypothesized to reflect behavioral despair which in turn may reflect depressive disorders in human. There was a significant correlation between clinical potency and the potency of antidepressants in both models. Thus, these two models are usually used to screen or evaluate antidepressants.
The monoamine hypothesis proposed that depression was a result of the depletion of 5-HT, NE and DA in addition to the activation of monoamine oxidase in the CNS. Depression is alleviated by an increase in the levels of monoamine neurotransmitters in the CNS. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, increase serotonin levels in the brain selectively. Hence fluoxetine was selected as the positive control in the present study. The duration of immobility was measured in the control and animal groups treated with standard antidepressant drug and test drugs. It was observed that fluoxetine reduced the duration of immobility in both the models significantly.
Synthesized dihydroyrimidinone derivatives produced significant antidepressant activity in both the FST and TST in dose dependant manner, with maximum activity at 400 mg/kg comparable to the activity of standard.
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Received on 06.03.2019 Modified on 25.05.2019
Accepted on 06.07.2019 © RJPT All right reserved
Research J. Pharm. and Tech. 2019; 12(11):5549-5553.
DOI: 10.5958/0974-360X.2019.00962.4