Synthesis and biological evaluation of some new coumarin derivatives

Article abstract of DOI:10.3390/80200275

Pyrimidino[5′,4′-6,5]-,pyridino[3′,2′-6,5]- and pyrrolo[3′,2′-5,6]4H-pyrano-[3,2-c][1]benzopyran-6-one derivatives (5-7 and 10) could be obtained via reaction of 2-amino-4-(p-bromophenyl)-3- cyano(carboethoxy)-4H,5H-pyrano[3,2-c][1]benzopyran-5-ones (3a,b) with a variety of reagents. Alkylation of (3b) with either 2-furoyl chloride or chloroacetyl chloride gave the 2-N-substituted derivatives (9a,b). Benzofurano[3,2-b]4H-pyran derivative (12) was also prepared. The antimicrobial activity of the prepared compounds was tested.

Full text of DOI:10.3390/80200275

Molecules 2003, 8, 275-286
molecules
ISSN 1420-3049
http://www.mdpi.org
Synthesis and Biological Evaluation of Some New Coumarin
Derivatives
M.A.Al-Haiza1* , M.S.Mostafa1 and M.Y.El-Kady2
1
Chemistry Department, College of Science, King Khalid University, Abha, P.O.Box 9059, Kingdom of
Saudi Arabia. Fax : 00966(07)2291036
2
Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt.
*Author to whom correspondence should be addressed; E – mail: mhaiza@hotmail.com
Received: 21 September 2002; in revised form: 12 January 2003 / Accepted: 15 February 2003 /
Published: 28 February 2003
Abstract: Pyrimidino[5`,4`-6,5]-,pyridino[3`,2`-6,5]- and pyrrolo[3`,2`-5,6]4H-pyrano-[3,2-
c][1]benzopyran-6-one derivatives (5-7 and 10) could be obtained via reaction of 2-amino-4-
(p-bromophenyl)-3-cyano(carboethoxy)-4H,5H-pyrano[3,2-c][1]benzopyran-5-ones (3a,b)
with a variety of reagents. Alkylation of (3b) with either 2-furoyl chloride or chloroacetyl
chloride gave the 2-N-substituted derivatives (9a,b). Benzofurano[3,2-b]4H-pyran derivative
(12) was also prepared. The antimicrobial activity of the prepared compounds was tested.
Keywords : Pyrano[3,2-c][1]benzopyran ; pyrimidino[5`,4`-6,5]-; pyrrolo[3`,2`-5,6]4H-
pyrano[3,2-c][1]benzopyran-6-one; antimicrobial activities.
Introduction
Coumarins are nowadays an important group of organic compounds that are used as bactericides [1-3],
fungicides [4], anti-inflammatory [5], anticoagulant [6] and antitumour agents [7,8]. These pharmacological
properties of coumarins aroused our interest in synthesizing several new compounds featuring different
heterocyclic rings fused onto the coumarin moiety with the aim of obtaining more potent pharmacologically
active compounds.

Molecules 2003, 8
276
Results and Discussion
Condensation of 4-hydroxycoumarin (4-hydroxy-2H-1-benzopyran-2-one, 1) with
-cyano-p-
a
bromocinnamonitrile (2a) in ethanol containing a catalytic amount of piperidine afforded a product which may
have two possible structures: 3a or 4a (Scheme 1).
Scheme 1
Ar
R
O
NH2
O
O
OH
O
4a,b
CN
R
+
Ar-CH=C
O
NC
R
1
2a,b
HO:
Ar
R
Ar
a
b
C6H4-Br-p
C6H4-Br-p
CN
COOC2H5
O
O
NH2
O
NH
R
R
O
O
Ar
Ar
O
O
O
3a,b
Ar
R
a
b
C6H4-Br-p
C6H4-Br-p
CN
COOC2H5
1
Structure 3a is favoured over 4a based on the H-NMR spectra which revealed the presence of a signal
at d 4.5- 5.0 ppm for one proton linked with a sp3 carbon. Signals at a similar position have been observed
for 4H-pyran [9]. If 4a were the reaction product, one would expect a 2H-pyran signal, appearing at lower
values. The formation of 3a was assumed to proceed via addition of the coumarinyl C-3 to the activated
double bond in 2a followed by cycloaddition of the Michael adduct. Compound 3b was prepared in similar
way using a -carboethoxy-p-bromocinnamonitrile (2b, Scheme 1).

Molecules 2003, 8
277
Scheme 2
HN
N
O
O
O
HCOOH
Ar
O
5
N
N
NH2
CN
Ar
O
NH2
O
HCONH2
Ar
O
O
O
O
6
3a
OH
Ar=C6H4-Br-p
N
O
NH2
Ar
O
O
HC(OC2H5)3
7
OC2H5
CN
N
O
Ar
O
O
8

Molecules 2003, 8
278
Compound 3a, as a typical enaminonitrile derivative [10], reacted with formic acid upon heating for
several hours to yield 7-(p-bromophenyl)-11-hydropyrimidino[5`,4`-6,5]4H-pyrano[3,2-c][1]benzo-pyran-
6,8-dione (5) (Scheme 2). Similarly, compound 3a reacted with formamide in the presence of formic acid and
dimethylformamide
to
produce
8-amino-7-(p-bromophenyl)pyrimidino[5`,4`-6,5]4H-pyrano[3,2-
c][1]benzopyran-6-one (6) (Scheme2).
It was reported that 2-amino-3-cyano-4H,5H-pyrano[3,2-c][1] benzopyran-5-one derivatives react with
triethyl orthoformate in acetic anhydride to produce the corresponding 3-cyano-2-ethoxy-methyleneamino
derivatives [4, 9]. In this study the reaction of 3a with triethyl orthoformate in acetic anhydride afforded a
product
formulated
as
8-amino-7-(p-bromophenyl)-10-hydroxypyridino[3`,2`-6,5]4H-pyrano[3,2-
c][1]benzopyran-6-one (7) rather than compound 8 (Scheme 2). Structure 7 was established for the reaction
product based on the following data: a) tis infrared spectrum revealed no absorption in the CN region,
-1
furthermore, it displayed absorption bands at 3448-3400 cm as a broad band (NH2 OH) and 1668 cm-1
(C=O); b) the mass spectrum of 7 exhibited molecular ion peaks at (M+) m/z 437 and 436, also, other peaks
appear at m/z 357, due to the loss of a bromine atom and 281 (100%) due to further loss of a phenyl group;
1
c) the H-NMR spectrum of 7 showed signals at d 2.50 (s, 2H, NH2), 4.82 (s, 1H, pyran H-4) and 7.26-
7.96 ppm (m, 9H, 8 ArH + 1H, which disappeared after D2O exchange, NH); d) treatment of 3a with acetic
-1
anhydride only gave a product showing in its IR spectrum absorption bands at 2210 cm (CN), a single band
-1
at 3330 cm-1 (NH), 1726 (lactone C=O) and 1676 cm (C = O).
Reaction of 3b with either 2-furoyl chloride or chloroacetyl chloride in dry acetone containing potassium
carbonate afforded the 2-N-furoyl amino-3-carboethoxy-4-(p-bromophenyl)-4H,5H-pyrano[3,2-
c][1]benzopyran-5-one derivative (9a) and 2-N-chloroacetylamino-3-carboethoxy-4-(p-bromophenyl)-
4H,5H-pyrano[3,2-c][1]benzopyran -5-one derivative (9b), respectively (Scheme 3). Cyclisation of
compound (9b) using sodium ethoxide afforded 7-(p-bromophenyl)-9-ethoxy-9,11-dihydropyridino[3`,2`-
6,5]4H-pyrano[3,2-c[ [1]benzopyran-6,8,10-trione (10) (Scheme 3).
Heating compound 3b with 4-bromophenacyl bromide in refluxing pyridine gave 7-(p-bromo-phenyl)-9-
[(p-bromophenyl)carbonyl]-8-hydroxypyrrolo[3`,2`-5,6]4H-pyrano-[3,2-c][1]benzopyran-6-one
(11)
(Scheme 3). Treatment of 3b with anthranilic acid in boiling pyridine afforded an unexpected
benzofuranopyran derivative which was formulated as 2-amino-4-(p-bromophenyl)-3-[N-phenyl-
carbamido]dihydrobenzofurano[3,2-b]-4H-pyran (12) (Scheme 3). The postulated structure of compound 12
was based on the following arguments: a) its IR spectrum reveals no absorption bands for an ester group and
-1
the carbonyl of a d-lactone, whereas an absorption band at 1667 cm (amide C=O) does appear; b) the 1H-
NMR spectrum of 12 showed signals at 7.01 (d, 1H, pyran H-4), 7.36 (d, 2H, furano H) and 7.47-8.12 ppm
(m, 16H, ArH+ NH2+NH).

Molecules 2003, 8
279
Scheme 3
O
O
OC2H5
O
HN
NHR
COOC2H5
Ar
O
O
O
O
9b
NaOC2H5
Ar
O
9a,b
a,R=
10
2-furoyl
b, = COCH2Cl
NH2
O
NH2
COOC2H5
Anthranilic
acid
O
N
H
O
O
Ar
Ar
O
O
3b
Ar=C6H4-Br-p
12
Br
p-bromophenacyl bromide
Br
HN
O
O
HN
O
O
OH
O
O
Ar
Ar
O
O
O
11

Molecules 2003, 8
280
Biological Activity
All the compounds prepared were screened for their activity against Gram-positive bacteria
(Staphylococcus aureus, Bacillus subtilis, Bacillus cereus), Gram-negative bacteria (Pseudomonas
aurignosa, Echerichia coli, Enterobacter aerogenes), as well as fungi (Aspergillus niger, Penicillium
italicum, Fusarium oxysporum). The results are given in Tables 1 and 2.
Table 1. Antibacterial activity of the prepared compounds
Organisms*
Compd.
1
2
3
4
5
6
3a
28
25
22
29
20
22
24
28
18
20
29
11
17
18
22
14
13
14
14
15
15
12
19
15
16
18
16
10
10
19
14
13
20
10
10
10
18
18
16
8
20
19
13
21
22
15
13
15
12
29
36
10
11
12
20
11
15
13
15
11
16
10
3b
5
6
7
9a
9b
10
12
10
19
11
11
12
Amoxicillin
* Organisms : 1- Staphylococcus aureus, 2-Bacillus subtilis, 3- Bacillus cereus,
4- Pseudomonas aurignosa, 5-Echerichia coli and 6- Enterobacter aerogenes.
It is apparent from the data listed in Table 1 that some of the synthesized compounds showed antibacterial
activity comparable to that of amoxicillin, the reference drug used. However, concerning the activity against
gram-positive bacteria (Bacillus subtilis), the pyrimidino[5`,4`-6,5]4H-pyrano[3,2- c][1]-benzopyran-6-one
(6) showed excellent activity, compounds 3b and 5 exhibit good activity , whereas compounds 7, 9b,10, 11
and 12 showed moderate activity . On the other hand, the Gram – negative bacteria (Pseudomonas
aurignosa) showed high responses to five of the prepared products. Dihydrobenzofurano[3,2-b]-4H-pyran
(12) showed the maximum activity, higher than that of amoxicillin. Compound 6 exhibits excellent antibacterial
activity towards Enterobacter aerogenes.
Concerning the data of antifungal activity in Table 2, compound 5 showed excellent activity against
Aspergillus niger, comparable to mycostatin , while compounds 7 and 8 exhibit good activity . Also,
compound 9a displays moderate activity toward Penicillium italicum. In general, the data obtained from the
microbiological screening showed that the activity of some synthesized compounds is equal to and sometimes
greater than those of the reference drugs used.

Molecules 2003, 8
281
Table 2. Antifungal activity of the prepared compounds
Organisms*
Compd.
A
B
C
12
15
21
14
16
12
18
10
10
12
12
11
15
12
16
20
22
20
12
13
18
20
20
19
20
18
18
19
22
19
11
11
26
3a
3b
5
6
7
9a
9b
10
11
12
Mycostatin
*Organisms : A) Aspergillus niger,B) Penicillium italicumand C) Fusarium Oxysporum
Conclusions
2-Amino-4-(p-bromophenyl)-3-cyano(carboethoxy)-4H,5H-pyrano-[3,2-c][1]benzo-pyran-5-ones
(3a,b) were used as starting materials to synthesize new coumarin derivatives containing heterocyclic rings
fused onto a coumarin moiety. Compound 3a reacts with formic acid, formamide and triethyl orthoformate to
produce 7-(p-bromophenyl) -11- hydropyrimidino[5`,4`-6,5]-4H-pyrano[3,2-c][1]-benzopyran-6,8-dione
(5), 8-amino-7-(p-bromophenyl)pyrimidino[5`,4`-6,5]4H-pyrano[3,2-c][1]-benzopyran-6-one (6) and 8-
amino-7-(p-bromophenyl)-10-hydroxypyridino[3`,2`-6,5]-4H-pyrano[3,2-c][1]benzopyran-6-one
(7),
respectively.
Compound 3b also reacted with either 2-furoyl chloride or chloroacetyl chloride to afford 2-N-
furoylamino-3-carboethoxy-4-(p-bromophenyl)-4H,5H-pyrano[3,2-c][1]benzopyran-5-one (9a) and 2-N-
chloroacetylamino-3-carboethoxy-4-(p-bromophenyl)-4H,5H-pyrano[3,2-c][1]benzopyran-5-one
(9b),
which cyclized into 7-(p-bromophenyl)-9-ethoxy-9,11-dihydro-pyridino[3`,2`-6,5]4H-pyrano[3,2-
c][1]benzopyran-6,8,10-trione (10). In addition compound (3b) reacted with 4-bromophenacyl bromide and
anthranilic acid to yield 7-(p-bromophenyl)-9-[(p-bromo-phenyl)carbonyl]-8-hydroxypyrrolo[3`,2`-5,6]4H-
pyrano-[3,2-c][1]benzopyran-6-one (11) and 2-amino-4-(p-bromophenyl)-3-[N-phenyl-carbamido]-
dihydrobenzofurano[3,2-b]-4H-pyran (12), respectively.

Molecules 2003, 8
Experimental
General
282
Melting points were taken on an Electrothermal capillary melting point apparatus and are uncorrected. The
microanalyses were done at Faculty of Scinece, King Khalid University. Infrared spectra were recorded on a
1
Jasco FT/IR 460, using KBr disks. H-NMR Spectra were recorded on JEOL EX-270 MHz NMR
Spectrometer. Mass spectra were recorded on a Finnigan Mat SSQ-7000 mass spectrometer.
BiologicalTests
Standard drugs (amoxicillin for bacteria and mycostatin for fungi) were used at a concentration of 1000
ppm for comparisons. The biological activity of these compounds have been evaluated by filter paper disc
method [11] after dissolving them in N,N-dimethylformamide to obtain a 1mg/mL solution (1000 ppm). The
inhibition zones of microbial growth surrounding the filter paper disc (5 mm) were measured in millimeters at
the end of an incubation period of 3 days at 37°C for Echerichia coli and at 28°C for other bacteria and
fungi. N,N-dimethylformamide alone showed no inhibation zone.
2-Amino-4- (4`-bromophenyl)-3-cyano-4H,5H-pyrano[3,2-c][1]benzopyran-5-one (3a).
A solution of 4-hydroxycoumarin (1, 1.62 g, 0.01 mole) and a -cyano-p-bromocinnamonitrile (2a, 2.32
g, 0.01 mole) in ethanol (20 mL) containing piperidine (0.5 mL) was heated for 30 min. The solid product
that precipitated during the reflux was filtered off, dried and recrystallised from dioxane to give 3a (cf. Table
-1
3). IR: 3387-3316 (NH2), 2191 (CN) and 1710 cm (lactone C = O); 1H-NMR (DMSO-d6) d 4.47 (s, 1H,
pyran H-4), 7.2 (s, 2H, NH2), and 7.3-8.0 ppm (m, 8H, ArH); MS: m/z 394 (M+,,8.41%), 328 (23.87), 315
(3.85), 249 (100), 239 (40.92), 153 (4.08), 120 (20.86) 92 (26.33), 66 (15.15).
2-Amino-4-(4`-bromophenyl)-3-carboethoxy-4H,5H-pyrano[3,2-c][1]- benzopyran -5-one (3b).
A solution of 4-hydroxycoumarin (1, 1.62 g, 0.01 mole) and a -carboethoxy-p-bromo-cinnamonitrile (2b,
2.79 g, 0.01 mole) in ethanol (20 mL) containing piperidine (0.5 mL) was heated under reflux for 8h. The
solvent was removed under reduced pressure and the residue was triturated with methanol to give a yellow
solid which filtered off, dried and recrystallised from benzene to produce 3b (cf. Table 3). IR: 3338-3280
(NH2), 1730 (ester) and 1697 cm-1 (lactone C = O); 1H-NMR: d 1.11 (t, 3H, CH3), 3.99 (q, 2H, CH2),4.65
(s, 1H, Pyran H-4) and 7.18-7.9 ppm (m, 10H, ArH+ NH ); MS: m/z 441 (M+,50%), 368 (28), 286 (100),
2
249 (32.86), 121 (39.65), 92 (4.74).

Molecules 2003, 8
283
7-(p-Bromophenyl)-11-hydropyrimidino[5`,4`-6,5]4H-pyrano[3,2-c][1]-benzopyran-6,8-dione (5).
A mixture of 3a (3.9 g, 0.01 mole) and formic acid (10 mL) was heated at reflux for 10 h and then left to
cool. The white crystals product thus formed was filtered off and recrystallised from ethanol to give 5 (cf.
-1
Table 3). IR: 3443 (NH), 1718 (lactone C =O) and 1662 cm (C = O);1H-NMR: d 4.87 (s, 1H, Pyran H-
4) and 7.28-8.25 ppm (m, 10H, 8 ArH + NH-pyrimidine-H); MS: m/z 423 (M+, 28.54 %), 343 (32.12), 267
(100), 240 (12.94), 157 (5.05), 121 (18.65), 92 (7.94).
8-Amino-7-(p-bromophenyl)pyrimidino[5`,4`-6,5]4H-pyrano[3,2-c][1]-benzopyran-6-one (6).
Compound 3a (3.9 g, 0.01 mole) was added to a mixture of formamide (10 mL), formic acid (5mL)
and dimethylformamide (5mL). The reaction mixture was heated at reflux for 10h and then left to cool. The
solid product was filtered off and recrystallised from benzene to produce 6 (cf. Table 3). IR: 3426-3341
-1
(NH2), 3164 (NH) and 1725cm (lactone C = O); 1H-NMR: d 4.87 (s, 1H, pyran H-4) and 7.27-8.23 ppm
(m, 11H, 8 ArH+NH +pyrimidine H); MS: m/z 422 (M+, 32.81%), 343 (25.64), 267 (100), 240 (11.50),
2
212 (2.73), 140 (2.69), 121 (8.95), 92 (3.33).
8-Amino-7-(p-bromophenyl)-10-hydroxypyridino[3`,2`-6,5]4H-pyrano[3,2-c][1]benzopyran-6-one (7).
A mixture of 3a (3.9 g, 0.01 mole) and triethyl orthoformate (1.48 mL, 0.01 mole) in acetic anhydride (15
mL) was refluxed for 2h. The mixture was dissolved and then precipitated, cooled, filtered off and dried. The
-1
solid product was crystallised from DMF to give 7 (cf. Table 3). IR: 3448-3400 cm as a broad band
-1
1
(NH2, OH) and 1668 cm (C = O); H-NMR: d 2.50 (s, 2H, NH2), 4.82 (s, 1H, pyran H-4) and 7.26-7.96
ppm (m, 9H, 8 ArH + 1H, disappeared after D O exchange, NH); MS: m/z 437 (M+, 4.26%) and 436
2
(16.04), 357 (10.52), 281 (100%), 240 (7.04), 157 (11.12), 121 (7.80), 92 (2.58).
2-N-furoylamino-3-carboethoxy-4-(p-bromophenyl)-4H,5H-pyrano[3,2-c][1]benzopyran-5-one (9a).
A mixture of 3b (4.4 g, 0.01 mole), 2-furoyl chloride (1.3 g, 0.01 mole) and potassium carbonate (1.38 g,
0.01mole) in dry acetone (20 mL) was heated under reflux for 4h. The reaction mixture after cooling was
poured into water (100 mL). The solid that separated was collected, dried and recrystallised from ethanol to
yield compound 9a (cf. Table 3). IR: 3414 (NH), 1740 (ester), 1714 (lactone C=O), 1681 (amide C=O);
1H-NMR: d 1.11 (t, 3H, CH3), 3.99 (q, 2H, CH2), 4.80 (s, 1H, pyran H-4), 6.81-8.20 (m, 11H, ArH and
furan) and 11.18 ppm (s, 1H, disappeared after DO exchange, NH); MS: m/z 536 (M+ 1.99 %), 535
2
,
(5.71), 380 (70.53), 327 (18.81), 329 (20.20), 286 (23.37), 249 (78.38), 121 (19.65), 95 (100).

Molecules 2003, 8
284
2-N-chloroacetylamino-3-carboethoxy-4-(p-bromophenyl)-4H,5H-pyrano[3,2-c][1]benzopyran-5-one
(9b).
Prepared from 3b (4.4 g, 0.01mole) and chloroacetyl chloride (1.25 g, 0.01 mole) according to the
procedure described for 9a. IR: 3414 (NH), 1728 (ester), 1713 (lactone C=O), 1666 (amide C=O);
1H-NMR: d 1.11 (t, 3H, CH3), 3.99 (q, 2H, CH2), 4.4 (s, 2H, CH ), 7.20-7.90 ppm (m, 8H, ArH); MS:
2
519 (M+ 13.79 %), 518 (3.51), 364 (35.12), 362 (100), 286 (59.53), 240 (52.49), 121 (59.56), 92
,
(18.31).
7-(p-Bromophenyl)-9-ethoxy-9,11-dihydropyridino[3`,2`-6,5]4H-pyrano[3,2-c][1]benzopyran-6,8,10-
trione (10).
A mixture of 9b (5.1 g, 0.01 mole) and sodium metal (0.23 g, 0.01 mole) in absolute ethanol (15 mL) was
refluxed for 2h. After concentration and cooling, the mixture was poured into ice/acetic acid and allowed to
stir for 1h. The insoluble product was removed by filtration, dried and recrystallised from dilute ethanol to
-1
produce 10 (cf. Table 3). IR: 3419 (NH), 1716 (lactone C=O) and 1691-1651 cm (2 C=O); 1H-NMR: d
1.12 (t, 3H, CH ), 3.3 (broad s, 1H, disappeared after D2O exchange, NH), 3.91 (q, 2H, CH2), 4.69 (s, 1H,
3
pyran H-4) and 7.21-7.90 ppm (m, 8H, ArH).; MS: m/z 482 (M+, 0%), 443 (62.83), 368 (37.25), 286
(100), 240 (70.81), 121 (45.96), 92 (13.26) , 75 (5.78).
7-(p-Bromophenyl)-9-[(p-bromophenyl)carbonyl]-8-hydroxy-pyrrolo[3`,2`-5,6]4H-pyrano[3,2-c][1]-
benzopyran-6-one (11).
A solution of 3b (1.02 g, 0.0025 mole) in pyridine (20 mL) was treated with 4-bromophenacyl bromide
(5.08 g, 0.01 mole) and heated under reflux for 1h. The reaction mixture was poured into ice/HCl and the
separated solid was filtered off. The product was crystallised from dimethylformamide to give 11 (cf. Table 3).
-1
IR: 3471 (broad band NH and OH), 1694 (lactone C=O) and 1639 cm (C=O); 1H-NMR: d 4.7 (s, 1H,
pyran H-4), 6.5 (s, 1H, C9-H) and 7.8-9.0 ppm (m, 13H, ArH+NH proton); .MS: m/z 593 (M+ 0%), 459
,
(5.44), 276 (26.72), 274 (18.28), 185 (100), 184 (90.32), 154 (20.46), 120 (4.71), 89 (13.49), 79 (52.64).
2-Amino-4-(p-bromophenyl)-3-[N-phenyl carbamido]-dihydrobenzofurano [3,2-b]-4H-pyran (12).
A mixture of 3b (1.02 g, 0.0025 mole) and anthranilic acid (1.26 g, 0.01 mole) in pyridine (20mL) was
refluxed for 6h. The reaction mixture was poured into ice/HCl and the solid that separated was washed
several times with water, dried and recrystallised from benzene to produce 12 (cf. Table 3). IR: 3413 (NH2),
1
3236 (NH), 1667 (amide C=O ); H-NMR: d 7.01 (d, 1H, pyran H-4), 7.36 (d, 2H, furano H) and 7.47-
8.12 ppm (m, 16H, ArH+ NH +NH); MS: m/z 463 (M+,0%), 327 (100%), 325 (94.03), 247 (26.08), 218
2
(18.55), 119 (36.21), 102 (51.69), 92 (24.83).

Molecules 2003, 8
285
Table 3. Characterization data of the prepared compounds
Molecular
Analysis Calcd./Found
M.P.
Co
Yield (%)
Colour
Compd.
Formula
(M. wt.)
C
H
N
67
White
40
C19H11BrN2O3
(395.22)
57.74
57.81
57.03
56.99
56.76
56.68
56.89
57.10
57.68
57.93
58.22
58.10
53.25
53.56
57.27
57.11
54.66
54.87
62.22
62.01
2.81
2.70
3.65
3.70
2.62
2.46
2.86
2.79
2.99
3.20
3.38
3.43
3.30
3.45
3.31
3.46
2.54
2.34
4.13
3.98
7.09
6.92
3.17
3.06
6.62
6.43
9.95
9.90
6.40
6.11
2.61
2.36
2.70
2.70
2.90
3.00
2.36
2.45
6.05
5.90
3a
3b
5
254
192
C21H16BrNO5
(442.27)
White
40
C20H11BrN2O4
(423.23)
>300
>300
>300
140
White
50
C20H12BrN3O3
(422.24)
6
White
55
C21H13BrN2O4
(437.25)
7
White
40
C26H18BrNO7
(536.33)
9a
9b
10
11
12
White
60
C23H17BrClNO6
(518.75)
158
White
45
C23H16BrNO6
(482.28)
196
Yellow
40
C27H15Br2NO5
(593.22)
230
Yellow
40
C24H19BrN2O3
(463.33)
282
Yellow
References
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substituted-3-[2-(5-substituted-2-furfurylidenehydrazino)-4-thiazolyl]coumarins. Boll. Chim. Farm,
2000, 139, 263-266.
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Sample Availability: Samples of compounds 3a, 3b, 5, 6, 7, 9a, 9b, 10, 11 and 12 are available from
MDPI. For other samples contact the authors.
© 2003 by MDPI (http://www.mdpi.org). Reproduction is permitted for noncommercial purposes.