Synthesis and in vitro microbiological evaluation of an array of biolabile 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides

Article abstract of DOI:10.1016/j.ejmech.2009.12.068

Biolabile 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides 34-42 have been synthesized and evaluated for their in vitro antibacterial and antifungal activities. The minimum inhibitory concentration tested for the same compounds against the same set of bacterial and fungal strains shows that the compounds 36 and 38 against β-Heamolytic streptococcus and Klebsiella pneumonia, 40 against Escherichia coli and Pseudomonas, have excellent antibacterial activity. Compounds 36, 38 and 42 show inhibition against Aspergillus flavus, compound 41 against Microsporum gypsuem, 42 against Mucor, and compounds 39 and 40 against Rhizopus.

Full text of DOI:10.1016/j.ejmech.2009.12.068

European Journal of Medicinal Chemistry 45 (2010) 1583–1589
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and in vitro microbiological evaluation of an array of biolabile
2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides
*
V. Kanagarajan, J. Thanusu, M. Gopalakrishnan
Synthetic Organic Chemistry Laboratory, Department of Chemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Biolabile 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides 34–42 have been synthesized and
evaluated for their in vitro antibacterial and antifungal activities. The minimum inhibitory concentration
tested for the same compounds against the same set of bacterial and fungal strains shows that the
Received 29 June 2009
Received in revised form
22 December 2009
Accepted 29 December 2009
Available online 14 January 2010
compounds 36 and 38 against b-Heamolytic streptococcus and Klebsiella pneumonia, 40 against Escherichia
coli and Pseudomonas, have excellent antibacterial activity. Compounds 36, 38 and 42 show inhibition
against Aspergillus flavus, compound 41 against Microsporum gypsuem, 42 against Mucor, and compounds
39 and 40 against Rhizopus.
Keywords:
2-Amino-4,6-diarylpyrimidines
Morpholine
Ó 2010 Elsevier Masson SAS. All rights reserved.
Acetamide
Chloroacetyl chloride
Antibacterial activity
Antifungal activity
1. Introduction
inflammatory diseases, pain, migraine and asthma [12]. Tride-
morphÒ, a morpholine derivative was used as an antifungal agent
Now-a-days, there has been a growing interest pertaining to the
synthesis of bioactive compounds in the field of organic chemistry.
Among the nitrogen containing heterocyclic compounds, pyrimi-
dines apparently gained considerable importance owing to their
varied biological properties and therapeutical importance. Pyrim-
idines are the basic nucleus in nucleic acids and have been asso-
[13]. 4-Phenyl morpholine derivatives were reported to possess
anti-inflammatory [14] and central nervous system [15] activities.
Besides these, amides are well known for their therapeutic values.
The chemistry of amides having a chloroacetyl group was also very
fascinating and has received significant attention now-a-days.
N-Benzyl-b-chloropropionamide was a well-proven anticonvulsant
ciated with
a
number of biological activities. Substituted
agent [16]. Moreover, synthesis and in vitro antimicrobial activity of
a new heterocyclic compounds which contain both morpholine and
pyrimidine moiety together namely 4-(4-morpholinophenyl)-6-
arylpyrimidin-2-amines were reported [17].
It was known from Scheme 1 that some clinically useful
compounds containing pyrimidines moiety exhibit strong tuber-
culosis (A) and antimicrobial activity (B). Besides, some of the
clinically important drugs contain morpholine moiety in addition
to N-heterocycles which are separated by one or higher number of
carbon atoms. Drugs derived from morpholine incorporated
compounds include dextromoramideÒ, (C) a narcotic analgesic and
doxapram HCl, (D) a respiratory stimulant. DoxapramÒ was used in
the treatment of respiratory depression following anaesthesia. N-
aminopyrimidine nuclei are common in marketed drugs such as
anti-atherosclerotic aronixilÒ, anti-histaminic thonzylamineÒ, anti-
anxielytic buspironeÒ, anti-psoriatic enazadremÒ, and other
medicinally relevant compounds. Some notable biological activity
of pyrimidine derivatives includes adenosine receptor antagonists
[1], kinase inhibitors [2], analgesic [3], anti-inflammatory [3],
inhibitors of cyclin-dependent kinases 1 and 2 [4], calcium channel
antagonist [5], anti-histaminic [6], antitubercular [7] activities.
Promising diverse pharmacological activities were shown by
various N-fuctionalized morpholines. They were reported to exert
a number of important physiological activities such as antidiabetic
[8], antiemetic [9], platelet aggregation inhibitors, anti-
hyperlipoproteinemics [8] bronchodilators, growth stimulants [10]
and antidepressants [11]. These were also used in the treatment of
Benzyl-b-chloropropionamide (E) was a very good anticonvulsant
and was marketed under the trade name HibiconÒ and HydraneÒ.
Recently, we exploited the synthesis of 3,4-dihydropyrimidin-
2(1H)-ones [18], 2-phenyl-3-(4,6-diarylpyrimidin-2-yl)thiazolidin-
4-ones [19], 6-aryl-1,2,4,5-tetrazinane-3-thiones [20], 2,6-
* Corresponding author. Tel.: þ91 4144 228 233.
E-mail address: profmgk@yahoo.co.in (M. Gopalakrishnan).
0223-5234/$ – see front matter Ó 2010 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2009.12.068

1584
V. Kanagarajan et al. / European Journal of Medicinal Chemistry 45 (2010) 1583–1589
N
O
O
S
N
O
N
N
S
N
O
(A)
Antitubercular agent
Cl
(C) Narcotic analgesic
F
F
O
N
HN
N
O
HN
N
S
(D) Respiratory stimulant
HN
N
O
O
Y
S
(B) Antimicrobials
O
X
N
Cl
N
H
N
N
O
HN
(E) Anticonvulsant
Newly synthesized antimicrobial agent
O
Scheme 1. Some of the synthetic compounds having the core pyrimidine, acetamide and morpholine nuclei with therapeutic activities.
diarylpiperidin-4-one derivatives [21-23] with a view to incorpo-
rate various other bioactive heterocyclic nucleus such as 1,2,3-
selenadiazoles, 1,2,3-thiadiazoles, diazepans intact for evaluation of
associated antibacterial and antifungal activities. Commercially
available drugs have either pyrimidine or morpholine moiety only.
In continuation of our earlier work on the synthesis of various
structurally diverse heterocyclic compounds, we thought it was
worthwhile to synthesize compounds comprising all pyrimidines,
chloroacetyl amides and morpholine moiety together to furnish
presence of sodium hydroxide yielded E-1,3-diarylprop-2-en-1-
ones 7–15. When E-1,3-diarylprop-2-en-1-ones 7–15 were refluxed
with guanidine nitrate in the presence of sodium hydroxide, 2-
amino-4,6-diarylpyrimidines 16–24 were formed. Various
substituted 2-chloro-N-(4,6-diarylpyrimidin-2-yl)acetamides 25–
33 were synthesized by electrophilic substitution reaction of
chloroacetyl chloride with the corresponding parent 2-amino-4,6-
diarylpyrimidines 16–24 in the presence of triethylamine as base
and toluene as solvent. Besides using sodium carbonate/potassium
carbonate as a base and toluene as solvent, appreciable yields were
obtained when triethylamine was used as a base and toluene as
solvent to effect chloroacetylation of 2-amino-4,6-diaryl-
pyrimidines at ambient temperature. In addition, while using
stronger bases as sodium hydroxide, potassium hydroxide and
pyridine individually to effect chloroacetylation, undesired prod-
ucts were obtained along with the expected product. The physical
and analytical data for compounds 7–33 was given in Table 1. Then,
condensation of 2-chloro-N-(4,6-diarylpyrimidin-2-yl)acetamides
25–33 with morpholine in the presence of anhydrous potassium
a
compact structure like title 2-morpholino-N-(4,6-diaryl-
pyrimidin-2-yl)acetamides 34–42 with the hope to develop some
promising antimicrobial agents.
2. Results and discussion
2.1. Chemistry
The Claisen–Schmidt condensation of equimolar quantities of
appropriate acetophenone and appropriate benzaldehyde in the

V. Kanagarajan et al. / European Journal of Medicinal Chemistry 45 (2010) 1583–1589
1585
Table 1
Physical and analytical data of intermediate compounds 7–33.
Compounds
m/z (M þ H)þ
m.p. (ꢀC)
Yield (%)
IR frequencies (cmꢁ1
)
Molecular formula
7
209
C15H12
223
C16H14
227
C15H11FO
239
C16H14O2
227
C15H11FO
253
C17H16O2
245
52
46
96
92
90
94
98
90
95
85
88
86
80
85
80
85
85
85
80
80
65
65
50
60
60
60
45
55
55
3059, 2925, 2847, 1659, 1602, 689, 746
O
O
8
3025, 2972, 2916, 2858, 1655, 1605, 822, 692, 669
9
58
3060, 3027, 2923, 2847, 1662, 1602, 1033, 764, 609
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
65
3057, 3013, 2949, 2907, 2841, 1656, 1598, 822, 687, 776
73
3064, 3033, 2934, 1659, 1596, 1011, 776, 687
82
3071, 3033, 2965, 2933, 2839, 1653, 1605, 1033, 815, 736, 678
3073, 3011, 2934, 1659, 1605, 1019, 742, 666
90
C15H10F2O
241
98
3065, 3046, 2916, 2858, 1654, 1604, 1025, 818, 737, 673
C
16H13FO
257
C16H13FO2
248
C16H13N3
262
C17H15N3
266
82
3071, 3022, 2983, 2940, 2841, 1659, 1600, 1018, 815, 742, 668
3478, 3303, 3184, 3062, 2967, 1629, 1568, 1364, 1225, 763, 697
3487, 3312, 3197, 3063, 2919, 3035, 1633, 1568, 1363, 1219, 819, 768, 697
3495, 3329, 3201, 3053, 2924, 1637, 1568, 1361, 1225, 1020, 766, 694
3366, 3325, 3199, 3005, 2972, 2934, 1643, 1565, 1360, 1240, 822, 772, 686
3495, 3328, 3201, 3050, 2983, 2927, 1637, 1569, 1360, 1225, 1044, 766, 692
3466, 3287, 3171, 3057, 2995, 2964, 2924, 1635, 1577, 1364, 1248, 1032, 816, 673, 582
3494, 3330, 3210, 3068, 2975, 2923, 1642, 1573, 1365, 1299, 1015, 565, 503
3497, 3315, 3195, 3073, 3041, 2920, 1638, 1574, 1361, 1227, 1016, 803, 668, 568
3478, 3318, 3203, 3053, 3003, 2927, 1634, 1572, 1369, 1299, 1036, 816, 665, 571
3391, 3194, 3055, 2923, 2849, 1671, 1610, 1561, 1361, 1227, 837, 759, 689
120
66
65
C
16H12FN3
278
C17H15N3O
266
C16H12FN3
292
C18H17N3O
284
134
101
52
89
C
16H11F2N3
280
C17H14FN3
296
C17H14FN3O
324
C18H14ClN3O
338
84
110
110
98
3358, 3296, 3200, 3150, 3058, 3035, 2958, 2919, 2851, 1681, 1594, 1530, 1339, 1203, 818, 815, 768, 691
3397, 3268, 3150, 3079, 3008, 2953, 2920, 2851, 1681, 1597, 1512, 1342, 1233, 1023, 840, 768, 689
3393, 3276, 3073, 3008, 2953, 2922, 2851, 1681, 1595, 1525, 1342, 1249, 833, 830, 768, 687
3386, 3260, 3112, 3064, 2953, 2921, 2851, 1681, 1599, 1509, 1358, 1229, 1018, 837, 767, 694
3328, 3002, 2958, 2920, 2848, 1682, 1591, 1513, 1336, 1248, 1025, 818, 814, 781, 634
C
19H16ClN3O
342
C18H13ClFN3O
354
C19H16ClN3O2
342
C18H13ClFN3O
368
202
116
81
106
204
85
C
20H18ClN3O2
360
C18H12ClF2N3O
356
C19H15ClFN3O
372
3339, 3271, 3079, 2980, 2958, 2919, 2851, 1676, 1600, 1510, 1343, 1234, 1013, 834, 782, 635
3214, 3068, 3030, 2953, 2920, 2852, 1682, 1598, 1509, 1357, 1232, 1017, 843, 817, 777, 684
3342, 3289, 3161, 3073, 2997, 2958, 2918, 2848, 1681, 1598, 1524, 1340, 1238, 831, 828, 1034, 701, 631
206
C19H15ClFN3O2
carbonate furnished 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)-
acetamides 34–42. Thus a four-step synthetic route furnished the
target compounds 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)ace-
tamides 34–42 in good yields. A general schematic representation
was given in Scheme 2. The physical and analytical data for
compounds 34–42 was given in Table 2. The structures of all the
newly synthesized compounds were supported by help of m.p.’s,
elemental analysis, FT-IR, MS, one-dimensional NMR (1H, 13C)
spectra.
Staphylococcus aureus, b-Heamolytic streptococcus, Vibreo cholerae,
Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa.
Ciprofloxacin was used as standard drug. Minimum inhibitory
concentration (MIC) in mg/mL values was reproduced in Table 3. Of
the nine compounds 34–42 tested for their antibacterial activity by
two-fold serial dilution method, compound 34 which has no
substitution at the para position of phenyl rings attached to C-4 and
C-6 carbons of pyrimidine moiety did not promote much activity
against the tested bacterial strains, whereas compounds 35 and 37
which have electron donating –CH3 and –OCH3 groups at the para
position of the phenyl ring exhibit moderate activity. The intro-
duction of p-fluoro substituted phenyl rings in place of phenyl ring
was found to enhance the antibacterial potency significantly. Thus
2.2. Antibacterial activity
Novel 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides
34–42 were tested for their antibacterial activity in vitro against
the compounds 36 and 38 against
b-H. streptococcus and

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V. Kanagarajan et al. / European Journal of Medicinal Chemistry 45 (2010) 1583–1589
H
O
H3C
O
X
Y
NaOH
20°C
HO
CH3
+
NH
stirring
1 h
NaOH
reflux
10 h
.HNO3
O
H2N
NH2
(E)-1,3-diarylprop-2-en-1-ones
Y
X
X
Y
7-15
1-3
4-6
X
H
Y
N
N
34
H
H
H
OCH3
F
35 CH3
36
37
38
F
H
H
NH2
2-amino-4,6-diarylpyrimidines
16-24
39 CH3 OCH3
40
41 CH3
42
F
F
F
F
OCH3
O
Et3N
reflux
Cl
6 h
C l
X
Y
N
N
HN
O
Cl
2-chloro-N-(4,6-diarylpyrimidin-2-yl)acetamides
25-33
Morpholine
Anhyd.K2CO3
reflux
8-10 h
Y
X
N
N
N
O
HN
O
2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides
34-42
Scheme 2. Synthesis of 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides.
K. pneumonia, while 40 against E. coli and Pseudomonas show
excellent antibacterial activity by inhibiting the growth of the
respective organisms at a minimum inhibitory concentration of
and –OCH3 group at the para position of the phenyl ring at C-6
carbon of pyrimidine exerted antibacterial activity against V. chol-
erae at 12.5 mg/mL MIC. Compounds 35 and 37 which have
6.25
m
g/mL.
respectively –CH3 and –OCH3 groups at the para position of the
phenyl rings at C-4/C-6 positions of the pyrimidine respectively did
not have high activity against V. cholerae. Conversely compound 39
Moreover, compound 39 having electron donating –CH3 group
at the para position of the phenyl ring at C-4 carbon of pyrimidine

V. Kanagarajan et al. / European Journal of Medicinal Chemistry 45 (2010) 1583–1589
1587
Table 2
Physical and analytical data of 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides 34–42.
Compounds
X
Y
Yield (%)
m.p. (ꢀC)
Elemental analysis (%)
m/z (M þ H)þ.
C found
(calculated)
H found
(calculated)
N found
(calculated)
Molecular
formula
34
35
36
37
38
39
40
41
42
H
H
58
44
45
88
76
54
41
48
50
45
40
50
40
45
50
45
55
50
70.55 (70.57)
71.06 (71.11)
67.30 (67.33)
68.28 (68.30)
67.30 (67.33)
68.87 (68.88)
64.31 (64.38)
67.95 (67.97)
65.36 (65.39)
5.88 (5.92)
6.20 (6.23)
5.35 (5.39)
5.95 (5.98)
5.36 (5.39)
6.22 (6.26)
4.87 (4.91)
5.66 (5.70)
5.46 (5.49)
14.90 (14.96)
14.38 (14.42)
14.25 (14.28)
13.82 (13.85)
14.25 (14.28)
13.36 (13.39)
13.62 (13.65)
13.76 (13.78)
13.21 (13.26)
375
C
22H22N4O2
CH3
F
H
389
C23H24N4O2
393
C22H21FN4O2
405
H
H
OCH3
C
23H24N4O3
H
F
393
C22H21FN4O2
419
C24H26N4O3
411
C22H20F2N4O2
407
CH3
F
OCH3
F
CH3
F
F
C23H23FN4O2
423
OCH3
C23H23FN4O3
which has both the –CH3 and –OCH3 groups at the above
mentioned positions exerted potent activity against V. cholerae.
Compound 41 (p-CH3/F – substituents in the phenyl ring at C-4 and
C-6 of pyrimidine) against S. aureus and V. cholerae and compound
42 (p-F/OCH3 – substituents in the phenyl ring at C-4 and C-6 of
pyrimidine) against Pseudomonas have exerted strong activity at an
carbons of pyrimidine in compound 41 exerted better activity at
a very minimum inhibitory concentration of 12.5 g/mL against
M. gypsuem. In addition compound 42 was found active against
Mucor at an MIC of 6.25 g/mL while compound 39 was moder-
g/mL). When the two
electron donating substitutents (–CH3 and –OCH3) on the aromatic
rings of compound 39 were replaced by the electron withdrawing
fluorines as in compound 40 the MIC against Rhizopus improved to
m
m
atively active on Rhizopus (MIC ¼ 12.5
m
MIC value of 12.5
mg/mL and 6.25 mg/mL respectively.
6.25 mg/mL. Compounds 36 and 38 with only one fluorine sub-
stitutents on the phenyl rings did not show notable activity either
2.3. Antifungal activity
against Mucor and Rhizopus.
The in vitro antifungal activity of 2-morpholino-N-(4,6-diary-
lpyrimidin-2-yl)acetamides 34–42 was studied against the fungal
strains viz., Aspergillus flavus, Mucor, Rhizopus and Microsporum
3. Conclusion
gypsuem. Fluconazole was used as a standard drug. MIC in mg/mL
values was reproduced in Table 3. Similar to antifungal activity,
compound 34 which has no substitution at the para position of
phenyl rings attached to C-4 and C-6 carbons of pyrimidine moiety
did not promote much activity against the tested fungal strains,
whereas compounds 35 and 37 which have electron donating –CH3
and –OCH3 groups at the para position of the phenyl rings exhibit
moderate activity. Compounds 36 and 38, both have electron
withdrawing fluoro group in the phenyl rings and 42, which have
either the fluoro and the methoxy groups at the para positions of
the phenyl rings at C-4 and C-6 positions of the pyrimidine
respectively were more potent against A. flavus (MIC val-
A four-step synthetic route furnished the target compounds
2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides 34–42 in
good yields and are characterized by their physical and analytical
data. The microbiological screening studies carried out to evaluate
the antibacterial and antifungal potencies of the newly synthe-
sized 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides 34–
42 were clearly known from Table 3. A close inspection of the in
vitro antibacterial and antifungal activity profile in differently
electron donating (CH3 and OCH3) and electron withdrawing –F
functional group substituted phenyl rings of novel target
compounds exerted strong antibacterial activity against all the
ue ¼ 6.25
m
g/mL). The presence of both methyl group and fluoro
tested bacterial strains. Compounds 36 and 38 against
streptococcus and K. pneumonia, 40 against E. coli and
b-H.
group at the para position of the phenyl rings at C-4 and C-6
Table 3
In vitro antibacterial and antifungal activities of 2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides 34–42 by two-fold serial dilution method.
Microorganisms
Minimum inhibitory concentration (MIC) in mg/mL
34
35
36
37
38
39
40
41
42
Ciprofloxacin
Fluconazole
Staphylococcus aureus
200
100
200
200
50
50
100
6.25
100
200
6.25
100
50
200
6.25
50
50
6.25
100
100
200
12.5
200
50
100
12.5
50
6.25
50
12.5
100
12.5
50
50
100
200
100
100
50
100
6.25
25
50
50
25
50
25
–
–
–
–
–
–
b
-Heamolytic streptococcus
100
100
50
100
50
100
100
200
100
50
Vibreo cholerae
Escherichia coli
Klebsiella pneumonia
Pseudomonas
100
50
6.25
Aspergillus flavus
Mucor
Rhizopus
200
100
100
200
100
50
50
6.25
200
200
100
100
200
100
100
6.25
50
100
200
100
50
12.5
50
12.5
6.25
6.25
100
200
100
50
6.25
6.25
200
100
–
–
–
–
50
25
25
25
Microsporum gypsuem
50
12.5

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V. Kanagarajan et al. / European Journal of Medicinal Chemistry 45 (2010) 1583–1589
Pseudomonas, showed excellent antibacterial activity by inhibiting
the growth of the respective organisms at a minimum inhibitory
4.1.3. 2-Morpholino-N-(4-(4-methylphenyl)-6-phenylpyrimidin-2-
yl)acetamide 35
concentration of 6.25
active against V. cholerae at 12.5
active also on S. aureus (MIC ¼ 12.5
domonas (MIC ¼ 6.25 g/mL). Noteworthy compounds 36, 38 and
42 against A. flavus (MIC value ¼ 6.25 g/mL), compound 41
(12.5 g/mL) against M. gypsuem, 42 against Mucor (MIC val-
ue ¼ 6.25 g/mL), compounds 39 and 40 against Rhizopus show
inhibition at an MIC of 12.5 and 6.25 g/mL respectively. Though
m
g/mL. Moreover, compound 39 and 41 were
g/mL MIC. Compound 41 was
g/mL) and 42 against Pseu-
IR (KBr) (cmꢁ1): 3325, 3196, 3058, 3032, 2952, 2920, 2852, 1683,
m
1611, 1536, 1360, 1233, 1113, 1018, 769, 694; 1H NMR (
d ppm): 2.37
m
(s, 3H, CH3 of phenyl ring), 2.68–2.66 (t, 4H, N(CH2)2, J ¼ 4.8 Hz),
m
3.48–3.46 (t, 4H, O(CH2)2, J ¼ 4.4 Hz), 3.89 (s, 2H, CH2), 6.67 (s, 1H,
m
H-5), 8.35–7.25 (m, 9H, Harom), 10.26 (bs,1H, NH); 13C NMR (
d ppm):
m
20.89 CH3, 45.99 N(CH2)2, 66.23 CH2, 67.27 O(CH2)2, 101.45 C-5,
126.88–130.30 –Carom, 131.11, 134.52, 137.39, 140.17 ipso carbons,
163.95 C-2, 164.70 C-4, 164.70 C-6, 169.45 C]O.
m
m
organofluorine compounds were virtually absent as natural
products, it was interesting to note that around 25% of drugs in the
pharmaceutical pipeline contain at least one fluorine atom.
Among the all tested compounds, fluorine substituted compounds
36, 38, 40, 41 and 42 exerted potent antimicrobial activity with
fluorine substitution is commonly used in contemporary medic-
inal chemistry to improve metabolic stability, bioavailability and
protein–ligand interactions [24]. The methods of action of these
compounds were unknown. These observations may promote
a further development of our research in this field. Further
development of this group of 2-morpholino-N-(4,6-diary-
lpyrimidin-2-yl)acetamides may lead to compounds with better
pharmacological profile than standard antibacterial and antifungal
drugs.
4.1.4. N-(4(4-Fluorophenyl)-6-phenylpyrimidin-2-yl)2-
morpholinoacetamide 36
IR (KBr) (cmꢁ1): 3366, 3207, 3056, 2953, 2917, 2851, 1670,
1600, 1540, 1361, 1229, 1113, 1019, 770, 694; 1H NMR (
d ppm):
2.65–2.63 (t, 4H, N(CH2)2, J ¼ 4.5 Hz), 3.49–3.46 (t, 4H, O(CH2)2,
J ¼ 4.7 Hz), 3.98 (s, 2H, CH2), 6.72 (s, 1H, H-5), 8.45–7.02 (m, 9H,
Harom), 10.30 (bs, 1H, NH); 13C NMR (
d ppm): 45.99 N(CH2)2, 66.24
CH2, 67.28 O(CH2)2, 101.59 C-5, 115.33–131.21 –Carom, 133.79,
136.14, 137.27 ipso carbons, 162.37 C-2, 163.72 C-6, 163.94 C-4,
168.30 C]O.
4.1.5. N-(4-Phenyl-6-(4-methoxyphenyl)-pyrimidin-2-yl)2-
morpholinoacetamide 37
IR (KBr) (cmꢁ1): 3331, 3199, 3060, 2962, 2920, 2850, 1687, 1605,
4. Experimental
1570, 1362, 1245, 1113, 831, 771, 693; 1H NMR (
d ppm): 2.68–2.66 (t,
4H, N(CH2)2, J ¼ 4.3 Hz), 3.51–3.49 (t, 4H, O(CH2)2, J ¼ 4.6 Hz), 3.85
4.1. Chemistry
(s, 3H, OCH3 of phenyl ring), 3.88 (s, 2H, CH2), 6.65 (s, 1H, H-5),
8.37–7.06 (m, 9H, Harom), 10.24 (bs, 1H, NH); 13C NMR (
d ppm):
Performing TLC assessed the reactions and the purity of the
products. All the reported melting points were taken in open
capillaries and were uncorrected. IR spectra were recorded in KBr
(pellet forms) on a Thermo Nicolet-Avatar-330 FT-IR spectropho-
tometer and noteworthy absorption values (cmꢁ1) alone were
listed. 1H and 13C NMR spectra were recorded at 400 MHz and
100 MHz respectively on Bruker Avance II 400 NMR spectrometer
using DMSO-d as solvent. The ESI þve MS spectra were recorded on
a Bruker Daltonics LC–MS spectrometer. Satisfactory microanalysis
was obtained on Carlo Erba 1106 CHN analyzer.
46.02 N(CH2)2, 55.27 –OCH3, 66.24 CH2, 67.29 O(CH2)2, 101.01 C-5,
113.89–128.49 –Carom, 129.05, 136.87, 137.76, ipso carbons, 163.85 C-
2, 164.48 C-4, 164.75 C-6, 171.01 C]O.
4.1.6. N-(4-Phenyl-6-(4-fluorophenyl)-pyrimidin-2-yl)2-
morpholinoacetamide 38
IR (KBr) (cmꢁ1): 3370, 3203, 3061, 2953, 2920, 2852, 1682,
1600, 1542, 1360, 1225, 1113, 1016, 767, 694; 1H NMR (
d ppm):
2.66–2.64 (t, 4H, N(CH2)2, J ¼ 4.4 Hz), 3.49–3.47 (t, 4H, O(CH2)2,
J ¼ 4.6 Hz), 3.93 (s, 2H, CH2), 6.72 (s, 1H, H-5), 7.97–7.04 (m, 9H,
By adopting the literature precedent 1,3-diaryl-prop-2-en-1-
ones 7–15 [25], 2-amino-4,6-diarylpyrimidines 16–24 [26] and 2-
chloro-N-(4,6-diarylpyrimidin-2-yl)acetamides 25–33 [27] were
synthesized.
Harom), 10.30 (bs, 1H, NH); 13C NMR (
d ppm): 45.87 N(CH2)2, 66.07
CH2, 67.13 O(CH2)2, 101.59 C-5, 114.71–131.21 –Carom, 133.07,
136.55, 137.28 ipso carbons, 161.84 C-2, 163.94 C-4, 163.97 C-6,
171.22 C]O.
4.1.1. General method for the synthesis of 2-morpholino-N-(4,6-
diarylpyrimidin-2-yl)acetamides 34–42
4.1.7. N-(4-(4-Methoxyphenyl)-6-(4-methylphenyl)pyrimidin-2-
yl)2-morpholinoacetamide 39
A
mixture of 2-chloro-N-(4,6-diarylpyrimidin-2-yl)aceta-
IR (KBr) (cmꢁ1): 3373, 3199, 2956, 2920, 2851, 1676, 1607, 1535,
mides 25–33 (0.005 mol), anhydrous potassium carbonate
(0.01 mol) and morpholine (0.005 mol) in dry toluene was
refluxed for about 8–10 h. After completion of the reaction,
potassium carbonate was removed by filtration and excess of
solvent was removed under reduced pressure. The obtained
residues were purified by column chromatography using
benzene and ethylacetate (1:1) mixture as eluent which afforded
2-morpholino-N-(4,6-diarylpyrimidin-2-yl)acetamides 34–42 in
good yields.
1362, 1300, 1112, 818, 728, 668; 1H NMR (
d ppm): 2.35 (s, 3H, CH3 of
phenyl ring), 2.65–2.63 (t, 4H, N(CH2)2, J ¼ 4.5 Hz), 3.49–3.46 (t, 4H,
O(CH2)2, J ¼ 4.7 Hz), 3.82 (s, 3H, OCH3 of phenyl ring), 3.85 (s, 2H,
CH2), 6.58 (s, 1H, H-5), 8.19–7.02 (m, 8H, Harom), 10.18 (bs, 1H, NH);
13C NMR (
d ppm): 20.82 CH3, 46.02 N(CH2)2, 55.26 –OCH3, 66.32
CH2, 67.30 O(CH2)2, 100.66 C-5, 113.87–129.11 –Carom, 129.67,
134.66, 140.02 ipso carbons, 161.15 C-2, 163.84 C-4, 164.24 C-6,
171.27 C]O.
4.1.8. N-(4,6-Bis(4-fluorophenyl)pyrimidin-2-yl)2-
morpholinoacetamide 40
4.1.2. 2-Morpholino-N-(4,6-diphenylpyrimidin-2-yl)acetamide 34
IR (KBr) (cmꢁ1): 3314, 3193, 3058, 3030, 2920, 2851, 1682, 1600,
IR (KBr) (cmꢁ1): 3395, 3215, 3068, 2958, 2919, 2851, 1674, 1601,
1565, 1360, 1236, 1112, 761, 693; 1H NMR (
d
ppm): 2.65–2.63 (t, 4H,
1541, 1363, 1228,1113, 833, 669, 566; 1H NMR (
d ppm): 2.66–2.64 (t,
N(CH2)2, J ¼ 4.5 Hz), 3.49–3.47 (t, 4H, O(CH2)2, J ¼ 4.8 Hz), 3.91 (s,
4H, N(CH2)2, J ¼ 4.9 Hz), 3.49–3.47 (t, 4H, O(CH2)2, J ¼ 4.6 Hz), 3.97
2H, CH2), 6.69 (s, 1H, H-5), 8.20–7.30 (m, 10H, Harom), 10.25 (bs, 1H,
(s, 2H, CH2), 6.62 (s,1H, H-5), 8.45–6.74 (m, 8H, Harom),10.30 (bs,1H,
NH); 13C NMR (
d
ppm): 45.89 N(CH2)2, 66.23 CH2, 67.25 O(CH2)2,
NH); 13C NMR (
d ppm): 45.93 N(CH2)2, 66.07 CH2, 67.20 O(CH2)2,
101.27 C-5, 126.87–130.30 –Carom, 134.55, 137.38 ipso carbons,
163.91 C-2, 164.72 C-4, 164.72 C-6, 169.40 C]O.
101.37 C-5, 114.29–130.20 –Carom, 133.73, 131.47 ipso carbons,
162.42 C-2, 163.80 C-6, 163.80 C-4, 170.37 C]O.

V. Kanagarajan et al. / European Journal of Medicinal Chemistry 45 (2010) 1583–1589
1589
4.1.9. N-(4-(4-Methylphenyl)-6-(4-fluorophenyl)pyrimidin-2-yl)2-
Acknowledgements
morpholinoacetamide 41
IR (KBr) (cmꢁ1): 3340, 3200, 3062, 3032, 2952, 2920, 2852,1680,
Authors were thankful to NMR Research Centre, Indian Institute
of Science, Bangalore for recording spectra. One of the authors
namely V. Kanagarajan was grateful to Council of Scientific and
Industrial Research (CSIR), New Delhi, Republic of India for
providing financial support in the form of CSIR-Senior Research
Fellowship (SRF) in Organic Chemistry. J. Thanusu was thankful
Annamalai University authorities for providing financial support in
the form of Research Fellowship.
1603, 1537, 1361, 1226, 1113, 1016, 815, 724, 689; 1H NMR (
d ppm):
2.36 (s, 3H, CH3), 2.66–2.64 (t, 4H, N(CH2)2, J ¼ 4.3 Hz), 3.49–3.47 (t,
4H, O(CH2)2, J ¼ 4.6 Hz), 3.95 (s, 2H, CH2), 6.68 (s, 1H, H-5), 8.28–
7.27 (m, 8H, Harom), 10.26 (bs, 1H, NH); 13C NMR (
d ppm): 20.90
–CH3, 45.93 N(CH2)2, 66.08 CH2, 67.21 O(CH2)2, 101.24 C-5, 115.31–
127.98 –Carom, 129.67, 134.66, 140.02 ipso carbons, 161.38 C-2,
163.89 C-4, 164.83 C-6, 170.21 C]O.
4.1.10. N-(4-(4-Fluorophenyl)-6-(4-methoxyphenyl)pyrimidin-2-
yl)2-morpholinoacetamide 42
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4.2.2. In vitro antibacterial and antifungal activity
MIC in mg/mL values was carried out by two-fold serial dilution
method [28]. The respective test compounds 34–42 were dissolved
in dimethyl sulphoxide (DMSO) to obtain 1 mg mLꢁ1 stock solution.
Seeded broth (broth containing microbial spores) was prepared in
NB from 24 h old bacterial cultures on nutrient agar (Hi-media,
Mumbai) at 37 ꢂ 1 ꢀC while fungal spores from 1 to 7 days old
Sabouraud’s agar (Hi-media, Mumbai) slant cultures were sus-
pended in SDB. The colony forming units (cfu) of the seeded broth
were determined by plating technique and adjusted in the range of
104–105 cfu/mL. The final inoculums size was 105 cfu/mL for anti-
bacterial assay and 1.1–1.5 ꢃ102 cfu/mL for antifungal assay. Testing
was performed at pH 7.4 ꢂ 0.2 for bacteria (NB) and at a pH 5.6 for
fungi (SDB). Exactly 0.4 mL of the solution of test compound was
added to 1.6 mL of seeded broth to form the first dilution. One
milliliter of this was diluted with a further 1 mL of seeded broth to
give the second dilution and so on till six such dilutions were
obtained. A set of assay tubes containing only seeded broth was
kept as control. The tubes were incubated in BOD incubators at
37 ꢂ 1 ꢀC for bacteria and 28 ꢂ 1 ꢀC for fungi. MICs were recorded
by visual observations after 24 h (for bacteria) and 72–96 h (for
fungi) of incubation. Ciprofloxacin was used as standard for bacteria
studies and Fluconazole was used as standards for fungal studies.