Baylis-Hillman reaction assisted parallel synthesis of 3,5-disubstituted isoxazoles and their in vivo bioevaluation as antithrombotic agents

Bioorganic & Medicinal Chemistry 12 (2004) 2059–2077

Baylis–Hillman reaction assisted parallel synthesis

of 3,5-disubstituted isoxazoles and their in vivo bioevaluation

as antithrombotic agents^q

S. Batra,^a,*A. K. Roy,^aA. Patra,^aA. P. Bhaduri,^aW. R. Surin,^bS. A. V. Raghavan,^b

P. Sharma,^bK. Kapoor^band M. Dikshit^b,*

^aDivision of Medicinal Chemistry, Central Drug Research Institute, Lucknow 226 001, India

^bDivision of Pharmacology, Central Drug Research Institute, Lucknow 226 001, India

Received 3 February 2004; revised 23 February 2004; accepted 24 February 2004

Abstract—The solution-phase parallel synthesis involving reactions of Baylis–Hillman products of 3-substituted-5-isoxazolecarb-

aldehydes with nucleophiles and their in vivo antithrombotic evaluations are described along with the results of in vitro platelet

aggregation inhibition assay of a few compounds. Results of the detailed evaluation of one of the compounds as an inhibitor of

platelet aggregation are also presented.

1. Introduction

towards the discovery of newer antithrombotic agents,

which target one or more of these novel biochemical

parameters and has resulted in identifying a wide range

of new chemical compounds including various hetero-

cyclic derivatives.⁸The synthesis of various isoxazole-

derivatives and their bioevaluation as antithrombotic

has been recently reported.^9;10We have reported earlier

hits in chemical libraries generated from 5-isoxazole-

carbaldehydes.¹⁰In the light of these observations it was

desired to build diﬀerent molecular scaﬀolds simulating

3,5-disubstituted isoxazoles and this led to solution-

phase parallel synthesis of compounds utilizing Baylis–

Hillman reaction as the key step.

Thrombotic disorders, resulting from abnormalities in

the blood ﬂow, coagulation cascade or ﬁbrinolysis rep-

resent the major share of the various cardiovascular

diseases encountered both in developed and developing

countries.^1;2The current therapies used for prophylactic

and prevention have considerable limitations because

they require careful clinical monitoring and are associ-

ated with high incidence of cardiovascular events and

complications associated with bleeding.^3;4These thera-

pies include the use of the antiplatelet agents namely

aspirin and ticlopidine and anticoagulant agents such as

heparin and warfarin.^2;3The ever-increasing under-

standing of the pathophysiology and the molecular

mechanisms of thrombosis have helped in understand-

ing the role of various biochemical parameters in the

coagulation cascade.^2–7This has provided impetus

All the synthesized compounds were evaluated ﬁrst in

high-throughput screen (HTS) mode for thrombin

inhibition and later on were subjected to in vivo bio-

evaluation because earlier experience of this laboratory

indicated that many compounds, found inactive in vitro,

against protease activity assay of thrombin were how-

ever, protective in animal models. This observation can

be explained on the basis of various targets for anti-

thrombotic action by the drugs/test agents. During this

in vivo screening a number of hits obtained from the

chemical library reported here were identiﬁed. This

prompted us to adopt two diﬀerent strategies of bioas-

say. In the ﬁrst strategy, a few of the active compounds

were subjected to in vitro platelet aggregation inhibition

assay. In the second strategy, the most active compound

Keywords: Baylis–Hillman reaction; Isoxazolecarbaldehyde; Isoxazole;

Nucleophilic substitution; Substituted piperazine; Antithrombotic

activity; Platelet aggregation.

^qCDRI Communication no 6468. In portion presented at BNP-2004

(IUPAC Conference) N. Delhi 26th–31st January, 2004.

* Corresponding authors. Tel.: +91-522-2212411-18x4368; fax: +91-

522-2223405/2229338 (S.B.); tel.: +91-522-2212411-18x4254 (M.D.);

e-mail addresses: batra_san@yahoo.co.uk; madhudikshit@yahoo.

com

doi:10.1016/j.bmc.2004.02.023

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S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

was studied in greater detail for understanding the

mechanism of its biological action. The details of our

studies are presented here.

next step the nucleophilic substitution in adducts

2(A1,3-6-B2), obtained from reactions of aldehydes

(A1,3-6) and ethyl acrylate (B2), with substituted pip-

erazines and secondary amines (C2-7) aﬀorded com-

pounds 4(A1,3-6-B2-C2-7). In another synthetic strategy

the acetates 3(A1,3-4-B1-3, 5), derived from acetylation

of Baylis–Hillman adducts were subjected to nucleo-

philic substitution with N-methyl piperazine only to

obtain compounds 5(A1,3-4-B1-3, 5-C1). On the other

hand in a diﬀerent synthetic sequence the acetates

3(A1,3-4-B1-3) were ﬁrst subjected to S_N2⁰nucleophilic

substitution with hydride utilizing sodium borohydride

in the presence of DABCO in aqueous medium, to

obtain products 6(A1,3-4-B1-3). Further Michael addi-

tion of N-methyl piperazine on the double bond of these

compounds 6(A1,3-4-B1-3) led to amines 7(A1-3-4-B1-3-

C1).

2. Chemistry

The various isoxazole derivatives were synthesized by

solution-phase parallel synthesis utilizing three diﬀerent

synthetic strategies with Baylis–Hillman reaction¹¹as

the key step. Since during this exercise our major aim

was to discover the antithrombotic activity in synthe-

sized compounds, no attempt was made at any stage to

separate the diastereoisomeric mixtures. In the ﬁrst

instance Baylis–Hillman reactions of diﬀerent 5-iso-

xazolecarboxaldehydes (A1-6) with activated alkenes

(B1-5) were carried out to obtain adducts 2(A1-6-B1-5).

These were then subjected to nucleophilic substitution

by N-methyl piperazine (C1) to obtain diastereoisomeric

mixture of amines [4(A1-6-B1-5-C1)] (Scheme 1). All

these reactions were carried out in methanol and the

reaction mixtures after the completion of the reaction

were directly passed through a small band of basic

alumina column to obtain the desired amines. In the

3. Results and discussion

All new compounds belonging to series 4, 5, and 7 were

ﬁrst evaluated in the HTS mode against thrombin. None

of the compounds showed any promising activity (data

EWG

OH

R

EWG

OH

CHO

i

O

N

ii

O

N

O

N

Ar

1(A1-6)

Ar

4(A1-6-B1-5-C1)

4(A1,3-6-B2-C2-7)

2(A1-6-B1-5)

iii

R

EWG

OAc

R

EWG

ii

iv

ii

O

N

O

N

O

N

O

N

Ar

6(A1,3-4-B1-3)

Ar

5(A1,3-4-B-1-3,5-C1)

3(A1,3-4-B1-3,5)

7(A1,3-4-B1-3-C1)

R

No

C1

Ar

C₆H₅

4-(CH₃)C₆H₄

4-(OBn)C₆H₄

2-(Cl)C₆H₄

No

EWG

CO₂Me

CO₂Et

CO₂Bu-n

CO₂Bu-t

CN

No

B1

B2

B3

B4

B5

A1

A2

A3

A4

A5

N

Me

C2

C3

C4

N

COMe

4-(Cl)C₆H₄

2,4-(Cl)₂C₆H₃A6

N

OMe

N

F

C5

C6

C7

N

Scheme 1. Reagents: (i) alkene, DABCO; (ii) amine, MeOH; (iii) AcCl, pyridine, CH₂Cl₂; (iv) DABCO, NaBH₄, THF/H₂O.

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2061

not shown). On the basis of the experience of this lab-

oratory, stated earlier in this communication, in vivo

antithrombotic activity including the eﬀect on the

bleeding time was evaluated. Initially the bioevaluation

of compounds represented by structure 4 (entries 1–30,

Table 1) was carried out. These were synthesized using

diversity at two points namely the changes in the sub-

stituents on the phenyl ring and in the electron-with-

drawing group (EWG). The methyl piperazine moiety

representing R in all these compounds remained

unchanged. The results of the bioevaluation indicated that

compounds possessing the ethyl ester group as the EWG

with unsubstituted phenyl (entry 7) and o-chloro-phenyl

(entry 9) as the substituents at position 3 of the isoxazole

ring exhibited signiﬁcant antithrombotic activity. The

next set of compounds 4(A1,3-6-B2-C2-7) (entries 31–

60) in which the methyl piperazine moiety was replaced

with other substituents did not elicit any antithrombotic

activity. This led to the next step in which the need of the

secondary hydroxyl group for eliciting antithrombotic

activity was evaluated by subjecting compounds repre-

senting by series 5 (entries 61–72) and 7 (entries 73–81)

for bioevaluation. In both the series, modiﬁcations were

made in substituents on the phenyl ring and in EWG

keeping the N-methyl piperazine moiety as the only

representative of R.

Results of in vivo evaluation of all the compounds

represented by series 4, 5, and 7 are presented in Table 1.

Out of all the compounds evaluated, seven compounds

showed activity more than 50% while 13 compounds

exhibited activity between 20–50%. Any activity below

20% was not considered as signiﬁcant activity. All the

seven compounds showing more than 50% activity in the

antithrombotic assay belong to series 4. These com-

pounds also had pronounced eﬀect on the bleeding time.

All these compounds had unsubstituted phenyl (entries

1, 7, 13, and 19) or o-chloro phenyl (entries 4, 10, and

Table 1. Results of the in vivo antithrombotic activity of compounds belonging to series 4, 5 and 7

Entry no

Compound no

Antithrombotic

activity (% protec-

tion at 30 lM/kg)

Bleeding time

(% increase at

30 lM/kg)

Entry no Compound no

Antithrombotic

activity (% protec-

tion at 30 lM/kg)

Bleeding time

(% increase at

30 lM/kg)

1

4A1B1C1

4A2B1C1

4A3B1C1

4A4B1C1

4A5B1C1

4A6B1C1

4A1B2C1

4A2B2C1

4A3B2C1

4A4B2C1

4A5B2C1

4A6B2C1

4A1B3C1

4A2B3C1

4A3B3C1

4A4B3C1

4A5B3C1

4A6B3C1

4A1B4C1

4A2B4C1

4A3B4C1

4A4B4C1

4A5B4C1

4A6B4C1

4A1B5C1

4A2B5C1

4A3B5C1

4A4B5C1

4A5B5C1

4A6B5C1

4A1B2C2

4A3B2C2

4A4B2C2

4A5B2C2

4A6B2C2

4A1B2C3

4A3B2C3

4A4B2C3

4A5B2C3

4A6B2C3

50

80, 150

NA

37.5

38

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

4A3B2C4

4A4B2C4

4A5B2C4

4A6B2C4

4A1B2C5

4A3B2C5

4A4B2C5

4A5B2C5

4A6B2C5

4A1B2C6

4A3B2C6

4A4B2C6

4A5B2C6

4A6B2C6

4A1B2C7

4A3B2C7

4A4B2C7

4A5B2C7

4A6B2C7

5A1B1C1

5A3B1C1

5A4B1C1

5A1B2C1

5A3B2C1

5A4B2C1

5A1B3C1

5A3B3C1

5A4B3C1

5A1B5C1

5A3B5C1

5A4B5C1

7A1B1C1

7A3B1C1

7A4B1C1

7A1B2C1

7A3B2C1

7A4B2C1

7A1B3C1

7A3B3C1

7A4B3C1

NA

40

NA

29

2

NA

20

3

NA

24

4

60

5

NA

60

NA

50

6

7

NA

30

8

20

NA

ND

30

NA

12.5

ND

25

9

NA

80

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

NA

45

ND

NA

12.5

NA

ND

37.5

NA

112.5, 146

ND

75

NA

20

70

40

NA

ND

NA

20

NA

12.5

NA

ND

NA

18

30

NA

60

NA

30

80

NA

80

NA

62.5

ND

NA

37.5

NA

12.5

62.5

NA

40

NA

25

NA

10

20

NA

12.5

NA

37.5

NA

12.5

NA

ND

30

NA

20

NA

30

NA

Any in vivo % protection below 20% has been mentioned as NA while any eﬀect that is less than 10% on the bleeding time has been mentioned as NA

(not active).

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S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

Table 3. Eﬀect of 4A4B2C1 on coagulation parameters

22) group as the substituents at position 3 of the isox-

azole ring. It was also observed that the deletion of the

secondary hydroxyl group in the analogues of the active

compounds led to total loss of biological activity. In

order to provide a plausible explanation for this obser-

vation, a set of compounds, comprising of active com-

pounds of series 4 and inactive compounds of series 5

and 7, was subjected to in vitro ADP induced platelet

aggregation assay. These compounds were A1B2C1 (4,

5, and 7, entries 7, 64 and 77, respectively), A4B2C1 (4,

5, and 7, entries 10, 66 and 78, respectively) and A1B5C1

(4 and 5, entries 25 and 70, respectively). It was observed

that most of the compounds, found inactive in the in

vivo assay, showed signiﬁcant inhibition against ADP

induced aggregation (Table 2). On the basis of these

results it was presumed that these compounds possibly

had problems with the bioavailability. Finally, only one

compound 4A1B2C1 was selected for a detailed study,

as this compound was the one that exhibited signiﬁcant

antithrombotic eﬃcacy with minimal eﬀects on the

bleeding time. It will be appropriate to mention that for

carrying out the detailed study, we proceeded with the

diastereoisomeric mixture of compound 4A1B2C1 as all

attempts to separate them failed.

Clotting time parameters

(in seconds)

Vehicle treated

4A4B2C1

Thrombin time (TT)

18.6 0.2

16.6 0.1

23.7 1.4

18.3 0.2

16.3 0.2

20.7 0.5

Prothrombin time (PT)

Activated partial throm-

boplastin time (APTT)

Table 4. Eﬀect of 4A4B2C1 on platelet aggregation

Agonist

IC₅₀(lM) (95% lower limit–95% upper limit)

Collagen

ADP

73.1 (59–90)

95.8 (75.8–121.2)

96.4 (71.6–129.6)

255.1 (198–328.6)

303.9 (258.3–357.7)

1214.2 (833–1770)

Thrombin

PMA

A23187

Arachidonic acid

aggregation. Hence the need arose to evaluate com-

pound 4A1B2C1 as an antagonist for platelet aggrega-

tion. Platelet aggregation inducers such as ADP,

collagen, and thrombin act at the receptor level to bring

about the activation of platelets and subsequent expo-

sure of GPIIb–IIIa.^{5–7;16–18}GPIIb–IIIa is ﬁbrinogen

receptor, which interlinks with the same receptor of the

adjacent platelets through ﬁbrinogen, leading to aggre-

gation of platelets.¹⁹While other inducers such as PMA,

AA, or A23187^20–22induces aggregation by acting at the

intermediate mediator level, PMA is also an activator of

protein kinase C (PKC), which in turn brings about the

phosphorylation of various proteins involved in the

activation pathway. Calcium ionophore A23187

increases the inﬂux of calcium ions into the platelets and

causes GPIIb–IIIa exposure and platelet aggregation.

Arachidonic acid is metabolized by the enzyme cyclo-

oxygenase in the platelets to form thromboxane A₂that

binds to the Tp-receptor and thus activates the platelets

in positive feed back mechanism leading to platelet

aggregation.¹⁹

In the preliminary in vivo antithrombotic activity eval-

uation, 4A1B2C1 showed signiﬁcant protection to col-

lagen and adrenaline induced thrombosis¹²at 30 lM/kg

dose, while 4A4B2C1 was not able to signiﬁcantly

reduce stasis induced thrombus formation in rabbits^13;14

(mean wet thrombus weight of 28ꢀ7 mg) at a dose,

which oﬀered signiﬁcant protection in mice. Heparin, a

potent inhibitor of thrombin action, exhibited a signiﬁ-

cant inhibition against thrombus formation in the rabbit

stasis model (maximum inhibition: 97.5% at 1 mg/kg

with a mean wet thrombus weight of 1ꢀ0.24 mg) in

comparison to the vehicle treated controls (mean wet

thrombus weight of 43ꢀ13 mg). Results suggest that the

compound might be acting predominantly at the platelet

targets to prevent thrombosis. Moreover, there was no

signiﬁcant prolongation of bleeding time, indicating that

this compound does not interfere with normal haemo-

stasis.¹⁵Noninterference with the haemostatic machin-

ery was also conﬁrmed by the insigniﬁcant alterations in

the clotting time parameters, as detailed in Table 3. It,

therefore, appeared that the compound 4A1B2C1 elic-

ited its antithrombotic activity by inhibiting platelet

Compound 4A1B2C1 inhibited platelet aggregation

irrespective of the agonists used (Table 4). Though it

was more selective to collagen, ADP and thrombin,

suggesting that it interfered at the receptor surface to

subsequently inhibit the events involved in the aggre-

gation, it seemed likely that this compound interfered at

the common receptor in the platelet aggregation cas-

cade. As all the cascades eventually terminate at the

expression of GPIIb–IIIa receptor and ﬁbrinogen

binding, it thus seems likely that compound 4A1B2C1

interfered with the ﬁbrinogen binding to the GPIIb–IIIa

receptor to display the antithrombotic activity. Thus,

compound 4A1B2C1 is a signiﬁcant lead molecule that

can be tailored further to derive a new class of anti-

thrombotic agents.

Table 2. Eﬀect of compounds on ADP (5 lM)-induced aggregation in

rats

Compounds

IC₅₀(lM) (95% lower

limit–95% upper limit)

In vivo % protection

from Table 1

4A1B2C1

5A1B2C1

7A1B2C1

4A4B2C1

5A4B2C1

7A4B2C1

4A1B5C1

5A1B5C1

20.0 (16.6–25.9)

8.0 (6.2–10.3)

60

20

78.8 (51.9–119.8)

95.8 (75.8–121.2)

28.1 (23.8–33.1)

82.3 (66.7–101.7)

216.4 (183.4–255.4)

124.7 (98.3–158.1)

NA

80

NA

80

4. Conclusion

NA

In conclusion, we have described facile parallel synthesis

and in vivo antithrombotic evaluation of various 3,5-

Data represents the mean IC₅₀of at least three independent experi-

ments.

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2063

disubstituted isoxazole derivatives obtained from

3-substituted-5-isoxazolecarbaldehyde utilizing Baylis–

Hillman chemistry. The present study has also provided

an insight into the plausible mode of action of these

derivatives.

methanol in 200 mL of chloroform was added in few

cases). The eluent was evaporated to obtain the required

products as pale yellow oils or solid. Most of the amines

were immediately converted to their corresponding

oxalate salts. To the solution of amine in dry methanol

(ca. 2–4 mL) was added a solution of oxalic acid dihy-

drate (1.0 equiv) in dry methanol (ca. 2–4 mL). The

mixture was hand shaked for 10–15 min. and then dry

ether was added freely to precipitate the salt. In few

cases the salts were recrystallized from methanol.

5. Experimental section

5.1. General methods

Reactions were run in oven-dried glassware. Dried sol-

vents were prepared by standard procedures. The col-

umn chromatography for all compounds other than

amines was carried on silica gel (60–1200 mesh) using

distilled solvents. The ﬁnal amines were passed through

basic alumina column using distilled solvents. Melting

points are uncorrected and were determined in capillary

tubes on a hot stage apparatus containing silicon oil. IR

spectra were recorded using an FTIR spectrophoto-

meter. ¹H NMR and ¹³C NMR spectra were run in

CDCl₃and recorded on either a 300 or a 200 MHz FT

spectrometer, using TMS as an internal standard

(chemical shifts in d values, J in Hz). The EIMS and

FABMS were recorded on appropriate spectrometers

and ESMS were recorded through direct injections in an

LCMS system. Elemental analyses were performed on a

microanalyzer. The diastereoisomeric ratios are based

5.4. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-

(3-phenyl-isoxazol-5-yl)-propionic acid methyl ester

(4A1B1C1) (6:1)

The product was obtained as colourless oil (59%); IR

1

(neat) 1735 (CO₂Me), 3319 (OH); H NMR (CDCl₃,

200 MHz) d ¼ 2:29 (s, 6H, 2 ꢁ NCH₃), 2.48–2.88 (m,

18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.06–3.22 (m, 4H,

2 ꢁ NCH₂), 3.66 (s, 3H, CO₂CH₃), 3.74 (s, 3H,

CO₂CH₃), 5.33, 5.37 (d, 1H, J ¼ 7:2 Hz, CH), 5.46, 5.48

(d, 1H, J ¼ 7:2 Hz, CH), 6.56 (s, 1H, @CH), 6,59 (s, 1H,

@CH), 7.43–7.46 (m, 6H, Ar–H), 7.78–7.82 (m, 4H, Ar–

H); Mass (EI) m=z 359 (M^þ). Oxalate salt: mp 206–

208 °C; Anal. [C₁₉H₂₃N₃O₄Æ2(CO₂H)₂] C, H, N.

1

on H NMR. Due to the complex nature of H NMR

spectra for compounds having C6 (4-benzylamino

piperidine) as substitution, they are not being provided.

The spectroscopic data corresponding to Baylis–Hill-

man adducts and their corresponding acetates have been

published earlier.²³

5.5. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-

(3-p-tolyl-isoxazol-5-yl)-propionic acid methyl ester

(4A2B1C1) (5:1)

The product was obtained as colourless oil (61%); IR

(neat, cm^ꢂ1) 1732 (CO₂Me), 3385 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 2:28 (s, 6H, 2 ꢁ NCH₃), 2.39 (s,

6H, 2 ꢁ CH₃), 2.47–2.86 (m, 18H, 8 ꢁ NCH₂and

2 ꢁ CH), 3.10–3.16 (m, 4H, 2 ꢁ NCH₂), 3.65 (s, 3H,

CO₂CH₃), 3.73 (s, 3H, CO₂CH₃), 5.31, 5.35 (d, 1H,

J ¼ 7:8 Hz, CH), 5.46, 5.50 (d, 1H, J ¼ 7:8 Hz, CH),

6.52 (s, 1H, @CH), 6.55 (s, 1H, @CH), 7.23, 7.27 (d, 4H,

J ¼ 8:0 Hz, Ar–H), 7.66, 7.70 (d, 4H, J ¼ 8:0 Hz, Ar–

H); Mass (ES+) m=z 374.67 (M^þ), 396.53 (M^þþNa).

Oxalate salt: mp 198–199 °C; Anal. [C₂₀H₂₇N₃

O₄Æ2(CO₂H)₂] C, H, N.

5.2. Baylis–Hillman reaction––general procedure

To a mixture of DABCO (0.12 g, 1.06 mmol) and

appropriate alkene (5.3 mmol) that has been stirred at rt

for 20 min. was added appropriate aldehyde from 1(A1-

6) (5.3 mmol) under stirring and the reaction was

allowed to proceed for a period 30 min. Thereafter 5%

aq HCl soln (50 mL) was added to the reaction mixture

to neutralize the base and extracted with ethyl acetate

(2 ꢁ 50 mL). The organic layers were combined, washed

with brine (75 mL), dried over anhyd Na₂SO₄and

evaporated under vacuum to yield an oily residue. The

residue was puriﬁed by column chromatography over

silica gel (60–120 mesh) using hexane/ethyl acetate as

eluent. A mixture of hexane/ethyl acetate (65:35, v/v)

yielded the desired products 2(A1-6-B1-5) as solids or

oils.

5.6. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-(4-methyl-piperazin-1-ylmethyl)-propionic acid methyl

ester (4A3B1C1) (9:1)

The product was obtained as light brown solid (58%),

1

mp 63–64 °C; IR (neat) 1732 (CO₂Me), 3424 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 2:28 (s, 3H, NCH₃), 2.46

(s, 3H, NCH₃), 2.43–2.93 (m, 18H, 8 ꢁ NCH₂and

2 ꢁ CH), 3.10–3.16 (m, 4H, 2 ꢁ NCH₂), 3.70 (s, 3H,

CO₂CH₃), 3.73 (s, 3H, CO₂CH₃), 5.11 (s, 4H,

2 ꢁ OCH₂O), 5.30, 5.34 (d, 1H, J ¼ 7:8 Hz, CH), 5.41,

5.45 (d, 1H, J ¼ 7:8 Hz, CH), 6.49 (s, 1H, @CH), 6.52 (s,

1H, @CH), 7.01, 7.05 (d, 4H, J ¼ 8:6 Hz, Ar–H), 7.30–

7.46 (m, 10H, Ar–H), 7.71, 7. 75 (d, 4H, J ¼ 8:6 Hz, Ar–

H); Mass (ESþ) m=z 466.93 (M^þþ1), 488.60 (M^þþNa).

Oxalate salt: mp 197–198 °C (dec); Anal. [C₂₆H₃₁N₃

O₅Æ2(CO₂H)₂] C, H, N.

5.3. Reaction with amines––general procedure

To the appropriate derivative from 2, 3 and 6 (5.0 mmol)

in methanol (4 mL) was added amine (6.0 mmol) and the

mixture was stirred at rt from 14–20 h (preferentially

overnight). On completion, the excess solvent was

evaporated and the residue was ﬁltered from a small

band of basic alumina using chloroform (0.5 mL of

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S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

5.7. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid methyl

ester (4A4B1C1) (5:1)

CH), 5.39, 5.42 (d, 1H, J ¼ 5:4 Hz, CH), 6.58 (s, 1H,

@CH), 6.60 (s, 1H, @CH), 7.42–7.45 (m, 6H, Ar–H),

7.77–7.84 (m, 4H, Ar–H); Mass (EI) m=z 373 (M^þ).

Oxalate salt: mp 196–198 °C; Anal. [C₂₀H₂₇N₃-

O₄Æ2(CO₂H)₂] C, H, N.

The product was obtained as colourless oil (61%); IR

1

(neat) 1733 (CO₂Me), 3331 (OH); H NMR (CDCl₃,

200 MHz) d ¼ 2:29 (s, 6H, 2 ꢁ NCH₃), 2.39–2.86 (m,

18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.09–3.14 (m, 4H,

2 ꢁ NCH₂), 3.66 (s, 3H, CO₂CH₃), 3.75 (s, 3H,

CO₂CH₃), 5.31, 5.35 (d, 1H, J ¼ 7:8 Hz, CH), 5.40, 5.44

(d, 1H, J ¼ 7:2 Hz, CH), 6.55 (s, 1H, @CH), 6.58 (s, 1H,

@CH), 7.32–7.49 (m, 6H, Ar–H), 7.69–7.74 (m, 2H, Ar–

H); Mass (EI) m=z 393 (M^þ). Oxalate salt: mp 198–

199 °C; Anal. [C₁₉H₂₄ClN₃O₄Æ2(CO₂H)₂] C, H, N.

5.11. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-

3-(3-p-tolyl-isoxazol-5-yl)-propionic acid ethyl ester

(4A2B2C1) (single)

The product was obtained as white solid (54%), mp

139–140 °C; IR (KBr, cm^ꢂ1) 1730 (CO₂Et), 3437 (OH);

¹H NMR (CDCl₃, 200 MHz) d ¼ 1:17 (t, 3H,

J ¼ 7:2 Hz, CH₃), 2.28 (s, 3H, NCH₃), 2.39 (s, 3H,

CH₃), 2.47–2.87 (m, 9H, 4 ꢁ NCH₂and CH), 3.04–3.14

(m, 2H, NCH₂), 4.10 (q, 2H, J ¼ 7:1 Hz, OCH₂), 5.29,

5.33 (d, 1H, J ¼ 7:8 Hz, CH), 6.65 (s, 1H, @CH), 7.22,

7.26 (d, 4H, J ¼ 8:0 Hz, Ar–H), 7.66, 7.70 (d, 4H,

J ¼ 8:0 Hz, Ar–H); Mass (EI) m=z 387 (M^þ). Oxalate

salt: mp 143–144 °C; Anal. [C₂₁H₂₉N₃O₄Æ2(CO₂H)₂] C,

H, N.

5.8. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid methyl

ester (4A5B1C1) (5:1)

The product was obtained as colourless oil (65%); IR

1

(neat) 1730 (CO₂Me), 3362 (OH); H NMR (CDCl₃,

200 MHz) d ¼ 2:29 (s, 6H, 2 ꢁ NCH₃), 2.39–2.89 (m,

18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.09–3.17 (m, 4H,

2 ꢁ NCH₂), 3.66 (s, 3H, CO₂CH₃), 3.74 (s, 3H,

CO₂CH₃), 5.31, 5.35 (d, 1H, J ¼ 7:8 Hz, CH), 5.42, 5.46

(d, 1H, J ¼ 7:4 Hz, CH), 6.52 (s, 1H, @CH), 6.56 (s, 1H,

@CH), 7.40, 7.44 (d, 4H, J ¼ 8:4 Hz, Ar–H), 7.71, 7.75

(d, 4H, J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 416.00

(M^þþNa). Oxalate salt: mp 198–200 °C; Anal.

[C₁₉H₂₄ClN₃O₄Æ2(CO₂H)₂] C, H, N.

5.12. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-3-hydro-

xy-2-(4-methyl-piperazin-1-ylmethyl)-propionic acid

ethyl ester (4A3B2C1) (4:1)

The product was obtained as white solid (50%), mp 69–

1

70 °C; IR (KBr) 1730 (CO₂Et), 3437 (OH); H NMR

(CDCl₃, 200 MHz) d ¼ 1:14–1:29 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.29 (s, 6H, 2 ꢁ NCH₃), 2.44–2.86

(m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 4.05–4.14 (m, 2q

merged, 4H, J ¼ 7:2 Hz, 2 ꢁ OCH₂), 5.11 (s, 4H,

2 ꢁ OCH₂O), 5.29, 5.31 (d, 1H, J ¼ 7:8 Hz, CH), 5.35,

5.38 (d, 1H, J ¼ 7:8 Hz, CH), 6.49 (s, 1H, @CH), 6.51 (s,

1H, @CH), 7.01, 7.05 (d, 2H, J ¼ 8:6 Hz, Ar–H), 7.32–

7.46 (m, 5H, Ar–H), 7.70, 7.74 (d, 2H, J ¼ 8:8 Hz, Ar–

H); Mass (ESþ) m=z 481.00 (M^þþ1), 502.67 (M^þþNa).

Oxalate salt: mp 217–219 °C; Anal. [C₂₇H₃₃N₃-

O₅Æ2(CO₂H)₂] C, H, N.

5.9. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-(4-methyl-piperazin-1-ylmethyl)-propionic acid methyl

ester (4A6B1C1) (5:1)

The product was obtained as colourless oil (56%); IR

(neat, cm^ꢂ1) 1736 (CO₂Me), 3447 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 2:29 (s, 6H, 2 ꢁ NCH₃), 2.34–

2.87 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.10–3.18 (m, 4H,

2 ꢁ NCH₂), 3.66 (s, 3H, CO₂CH₃), 3.74 (s, 3H,

CO₂CH₃), 5.33, 5.37 (d, 1H, J ¼ 7:6 Hz, CH), 5.41, 5.45

(d, 1H, J ¼ 7:4 Hz, CH), 6.70 (s, 1H, @CH), 6.71 (s, 1H,

@CH), 7.33, 7.35 (dd, 2H, J₁¼ 2:0 Hz, J₂¼ 8:2 Hz, Ar–

H), 7.50, 7.51 (d, 2H, J ¼ 2:0 Hz, Ar–H), 7.66, 7.70 (d,

2H, J ¼ 8:4 Hz, Ar–H); Mass (FABþ) m=z 428 (M^þþ1).

Oxalate salt: mp 171–172 °C; Anal. [C₁₉H₂₃Cl₂N₃-

O₄Æ2(CO₂H)₂] C, H, N.

5.13. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid ethyl ester

(4A4B2C1) (9:1)

The product was obtained as colourless oil (65%); IR

(neat) 1728 (CO₂Et), 3329 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 1:06–1:17 (m, 2t merged, 6H, J ¼ 7:2 Hz,

2 ꢁ CH₃), 2.26 (s, 3H, NCH₃), 2.28 (s, 3H, NCH₃), 2.48–

2.87 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 4.105–4.16 (m, 2q

merged, 4H, J ¼ 7:2 Hz, 2 ꢁ OCH₂), 5.32. 5.36 (d, 1H,

J ¼ 7:8 Hz, CH), 5.38. 5.42 (d, 1H, J ¼ 7:8 Hz, CH),

6.72 (s, 1H, @CH), 6.78 (s, 1H, @CH), 7.33–7.50 (m,

6H, Ar–H), 7.69–7.74 (m, 2H, Ar–H); ¹³C NMR

(CDCl₃, 50.32 MHz) d ¼ 14:39, 45.45, 46.23, 46.87,

53.68, 55.27, 56.55, 59.65, 61.65, 69.62, 70.39, 77.67,

103.47, 104.15, 127.48, 128.75, 130.78, 131.34, 133.27,

161.14, 170.88, 171.13, 172.72, 173.43; Mass (FABþ)

m=z 408 (M^þþ1). Oxalate salt: mp 205–206 °C; Anal.

[C₂₀H₂₆ClN₃O₄Æ2(CO₂H)₂] C, H, N.

5.10. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-

(3-phenyl-isoxazol-5-yl)-propionic acid ethyl ester

(4A1B2C1) (6:1)

The product was obtained as white solid (69%), mp 110–

1

111 °C; IR (KBr, cm^ꢂ1) 1728 (CO₂Et), 3220 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:14–1:27 (m, 2t merged,

6H, J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.29 (s, 3H, NCH₃), 2.31 (s,

3H, NCH₃), 2.45–2.87 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH),

3.10–3.16 (m, 4H, 2 ꢁ NCH₂), 4.05–4.16 (m, 2q merged,

4H, J ¼ 7:2 Hz, 2 ꢁ CH₂), 5.32, 5.35 (d, 1H, J ¼ 5:4 Hz,

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2065

5.14. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid ethyl

ester (4A5B2C1) (6:1)

J ¼ 7:2 Hz, 2 ꢁ CH₃), 1.21–1.29 (m, 4H, 2 ꢁ CH₂), 1.49–

1.63 (m, 4H, 2 ꢁ CH₂), 2.27 (s, 6H, 2 ꢁ CH₃), 2.39 (s,

6H, 2 ꢁ NCH₃), 2.42–2.86 (m, 18H, 8 ꢁ NCH₂and

2 ꢁ CH), 3.10–3.14 (m, 4H, 2 ꢁ NCH₂), 4.04 (t, 2H,

J ¼ 6:6 Hz, OCH₂), 4.13 (t, 2H, J ¼ 6:6 Hz, OCH₂),

5.31, 5.33 (d, 1H, J ¼ 5:4 Hz, CH), 5.38 (br s, 1H, CH),

6.52 (s, 1H, @CH), 6.55 (s, 1H, @CH), 7.23, 7.26 (d, 4H,

J ¼ 8:0 Hz, Ar–H), 7.67, 7.69 (d, 4H, J ¼ 8:0 Hz, Ar–

H); Mass (ESþ) m=z 416.27 (M^þþ1). Oxalate salt: mp

220–221 °C; Anal. [C₂₃H₃₃N₃O₄Æ2(CO₂H)₂] C, H, N.

The product was obtained as colourless oil (64%); IR

(neat) 1730 (CO₂Et), 3374 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 1:13–126 (m, 2t merged, 6H, J ¼ 7:2 Hz,

2 ꢁ CH₃), 2.28 (s, 6H, 2 ꢁ NCH₃), 2.33–2.92 (m, 18H,

8 ꢁ NCH₂and 2 ꢁ CH), 3.09–3.15 (m, 4H, 2 ꢁ NCH₂),

3.09–3.15 (m, 2q merged, 4H, J ¼ 7:0 Hz, 2 ꢁ OCH₂),

5.29, 5.33 (d, 1H, J ¼ 7:6 Hz, CH), 5.36, 5.40 (d, 1H,

J ¼ 7:6 Hz, CH), 6.53 (s, 1H, @CH), 6.56 (s, 1H, @CH),

7.40, 7.44 (d, 4H, J ¼ 8:4 Hz, Ar–H), 7.71, 7.75 (d, 4H,

J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 408.67 (M^þþ1),

430.40 (M^þþNa). Oxalate salt: mp 202–205 °C; Anal.

[C₂₀H₂₆ClN₃O₄Æ2(CO₂H)₂] C, H, N.

5.18. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-(4-methyl-piperazin-1-ylmethyl)-propionic acid butyl

ester (4A3B3C1) (5:1)

The product was obtained as colourless oil (57%); IR

(neat, cm^ꢂ1) 1729 (CO₂Bu-n), 3400 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 0:84 (t, 6H, J ¼ 7:2 Hz,

2 ꢁ CH₃), 1.21–1.32 (m, 4H, 2 ꢁ CH₂), 1.45–1.55 (m,

4H, 2 ꢁ CH₂) 2.28 (s, 6H, 2 ꢁ NCH₃), 2.38–2.82 (m,

18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.09–3.15 (m, 4H,

2 ꢁ NCH₂), 4.02–4.12 (m, 2t merged, 4H, J ¼ 6:6 Hz,

2 ꢁ OCH₂), 5.11 (s, 4H, 2 ꢁ OCH₂O), 5.29, 5.33 (d, 1H,

J ¼ 7:8 Hz, CH), 5.46, 5.50 (d, 1H, J ¼ 7:8 Hz, CH),

6.47 (s, 1H, @CH), 6.51 (s, 1H, @CH), 7.01, 7.05 (d, 4H,

J ¼ 8:8 Hz, Ar–H), 7.32–7.45 (m, 10H, Ar–H), 7.70,

7.74 (d, 4H, J ¼ 8:8 Hz, Ar–H); Mass (FAB+) m=z 508

(M^þþ1). Oxalate salt: mp 196–197 °C; Anal. [C₂₉H₃₇N₃-

O₅Æ2(CO₂H)₂] C, H, N.

5.15. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-(4-methyl-piperazin-1-ylmethyl)-propionic acid ethyl

ester (4A6B2C1) (3:1)

The product was obtained as colourless oil (61%); IR

(neat, cm^ꢂ1) 1730 (CO₂Et), 3404 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:14–1:33 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.29 (s, 6H, 2 ꢁ NCH₃), 2.47–2.86

(m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.10–3.15 (m, 2H,

NCH₂), 4.10 (q, 4H, J ¼ 7:2 Hz, OCH₂), 5.32, 5.36 (d,

1H, J ¼ 7:8 Hz, CH), 5.41, 5.44 (d, 1H, J ¼ 7:6 Hz,

CH), 6.70 (s, 1H, @CH), 6.71 (s, 1H, @CH), 7.32, 7.36

(dd, 1H, J₁¼ 2:0 Hz, J₂¼ 8:4 Hz, Ar–H), 7.51, 7.52 (d,

1H, J ¼ 2:0 Hz, Ar–H), 7.66, 7.70 (d, 1H, J ¼ 8:4 Hz,

Ar–H); Mass (ESþ) m=z 444.07 (M^þþ1), 464.00

(M^þþNa). Oxalate salt: mp 180–182 °C (dec); Anal.

[C₂₀H₂₅Cl₂N₃O₄Æ2(CO₂H)₂] C, H, N.

5.19. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid butyl

ester (4A4B3C1) (9:1)

The product was obtained as colourless oil (50%); IR

1

(neat) 1730 (CO₂Bu-n), 3329 (OH); H NMR (CDCl₃,

5.16. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-

(3-phenyl-isoxazol-5-yl)- propionic acid butyl ester

(4A1B3C1) (5:1)

200 MHz) d ¼ 0:87 (t, 6H, J ¼ 7:2 Hz, 2 ꢁ CH₃), 1.23–

1.34 (m, 4H, 2 ꢁ CH₂), 1.50–1.57 (m, 4H, 2 ꢁ CH₂) 2.28

(s, 3H, NCH₃), 2.31 (s, 3H, NCH₃), 2.48–2.83 (m, 18H,

8 ꢁ NCH₂and 2 ꢁ CH), 3.11–3.18 (m, 4H, 2 ꢁ NCH₂),

4.05 (t, 4H, J ¼ 6:6 Hz, 2 ꢁ OCH₂), 5.33, 5.37 (d, 1H,

J ¼ 8:0 Hz, CH), 5.45, 4.49 (d, 1H, J ¼ 7:8 Hz, CH),

6.72 (s, 2H, 2 ꢁ @CH), 7.32–7.50 (m, 6H, Ar–H), 7.69-

7.74 (m, 2H, Ar–H); Mass (EI) m=z 435 (M^þ). Oxalate

salt: mp 208–210 °C; Anal. [C₂₂H₃₀ClN₃O₄Æ2(CO₂H)₂]

C, H, N.

The product was obtained as colourless oil (57%); IR

(neat, cm^ꢂ1) 1708 (CO₂Bu-n), 3377 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 0:81–0:94 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 1.23–1.31 (m, 4H, 2 ꢁ CH₂),

1.47–1.56 (m, 4H, 2 ꢁ CH₂), 2.29 (s, 6H, 2 ꢁ NCH₃),

2.35–2.86 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.07–3.17

(m, 4H, 2 ꢁ NCH₂), 4.06 (t, 2H, J ¼ 6:6 Hz, OCH₂),

4.13 (t, 2H, J ¼ 6:6 Hz, OCH₂), 5.32, 5.34 (d, 1H,

J ¼ 7:8 Hz, CH), 5.36, 5.38 (d, 1H, J ¼ 7:8 Hz, CH),

6.55 (s, 1H, @CH), 6.58 (s, 1H, @CH), 7.43–7.45 (m,

6H, Ar–H), 7.77–7.84 (m, 4H, Ar–H); Mass (EI) m=z

401 (M^þ). Oxalate salt: mp 195–197 °C; Anal.

[C₂₂H₃₁N₃O₄Æ2(CO₂H)₂] C, H, N.

5.20. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid butyl

ester (4A5B3C1) (5:1)

The product was obtained as colourless oil (50%); IR

1

(neat) 1730 (CO₂Bu-n), 3330 (OH); H NMR (CDCl₃,

5.17. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-

(3-p-tolyl-isoxazol-5-yl)-propionic acid butyl ester

(4A2B3C1) (3:1)

200 MHz) d ¼ 0:84 (t, 6H, J ¼ 7:2 Hz, 2 ꢁ CH₃), 1.21–

1.32 (m, 4H, 2 ꢁ CH₂), 1.48–1.55 (m, 4H, 2 ꢁ CH₂) 2.29

(s, 6H, 2 ꢁ NCH₃), 2.48–2.83 (m, 18H, 8 ꢁ NCH₂and

2 ꢁ CH), 3.10–3.16 (m, 4H, 2 ꢁ NCH₂), 4.07 (m, 4H,

2 ꢁ OCH₂), 5.30, 5.32 (d, 1H, J ¼ 4:2 Hz, CH), 5.45,

5.47 (d, 1H, J ¼ 4:2 Hz, CH), 6.52 (s, 1H, @CH), 6.55 (s,

1H, @CH), 7.40, 7.44 (d, 4H, J ¼ 8:4 Hz, Ar–H), 7.71,

The product was obtained as pale yellow oil (61%); IR

(neat, cm^ꢂ1) 1709 (CO₂Bu-n), 3380 (OH); ¹H NMR

(CDCl₃, 300 MHz) d ¼ 0:82–0:93 (m, 2t merged, 6H,

2066

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

7.75 (d, 4H, J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 436.73

(M^þþ1), 458.67 (M^þþNa). Oxalate salt: mp >225 °C;

Anal. [C₂₂H₃₀ClN₃O₄Æ2(CO₂H)₂] C, H, N.

NMR (CDCl₃, 200 MHz) d ¼ 1:28 (s, 9H, C(CH₃)₃),

1.38 (s, 9H, C(CH₃)₃), 2.22 (s, 3H, NCH₃), 2.26 (s, 3H,

NCH₃), 2.32–2.80 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH),

2.96–2.99 (m, 4H, 2 ꢁ NCH₂), 5.04 (s, 4H, 2 ꢁ OCH₂O),

5.16, 5.19 (d, 1H, J ¼ 7:4 Hz, CH), 5.29, 5.31 (d, 1H,

J ¼ 7:4 Hz, CH), 6.41 (s, 1H, @CH), 6.44 (s, 1H, @CH),

6.94, 6.98 (d, 4H, J ¼ 8:8 Hz, Ar–H), 7.25–7.39 (m, 10H,

Ar–H), 7.63, 7.67 (d, 4H, J ¼ 8:8 Hz, Ar–H); Mass (EI)

m=z 507 (M^þ). Oxalate salt: mp 189–191 °C; Anal.

[C₂₉H₃₇N₃O₅Æ2(CO₂H)₂] C, H, N.

5.21. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-3-hydro-

xy-2-(4-methyl-piperazin-1-ylmethyl)-propionic acid

butyl ester (4A6B3C1) (5:1)

The product was obtained as pale yellow oil (52%); IR

(neat, cm^ꢂ1) 1729 (CO₂Bu-n), 3329 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 0:86 (t, 6H, J ¼ 7:2 Hz,

2 ꢁ CH₃), 1.23–1.34 (m, 4H, 2 ꢁ CH₂), 1.50–1.57 (m,

4H, 2 ꢁ CH₂), 2.28 (s, 3H, NCH₃), 2.31 (s, 3H, NCH₃),

2.48–2.83 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.11–3.18

(m, 4H, 2 ꢁ NCH₂), 4.04 (t, 4H, J ¼ 6:6 Hz, 2 ꢁ OCH₂),

5.32, 5.36 (d, 1H, J ¼ 8:0 Hz, CH), 5.45, 5.49 (d, 1H,

J ¼ 7:8 Hz, CH), 6.70 (s, 1H, CH), 6.72 (s, 1H, CH),

7.31, 7.36 (dd, 2H, J₁¼ 2:0 Hz, J₂¼ 8:4 Hz, Ar–H),

7.50, 7.51 (d, 2H, J ¼ 1:8 Hz, Ar–H), 7.66, 7.70 (m, 2H,

J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 470.80 (M^þþ1),

492.73 (M^þþNa). Oxalate salt: mp 208–210 °C; Anal.

[C₂₂H₂₉Cl₂N₃O₄Æ2(CO₂H)₂H₂O] C, H, N.

5.25. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid tert-butyl

ester (4A4B4C1)

The product was obtained as white solid (65%), mp 105–

1

107 °C; IR (KBr, cm^ꢂ1) 1724 (CO₂Bu-t), 3434 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:37 (s, 9H, C(CH₃)₃),

1.46 (s, 9H, C(CH₃)₃), 2.29 (s, 6H, 2 ꢁ NCH₃), 2.48–2.83

(m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.06–3.10 (m, 4H,

2 ꢁ NCH₂), 5.26, 5.30 (d, 1H, J ¼ 7:6 Hz, CH), 5.40,

5.44 (d, 1H, J ¼ 7:8 Hz, CH), 6.72 (s, 1H, @CH), 6.73 (s,

1H, @CH), 7.30–7.51 (m, 6H, Ar–H), 7.69–7.73 (m, 2H,

Ar–H); Mass (EI) m=z 435 (M^þ). Oxalate salt: mp 174–

176 °C; Anal. [C₂₂H₃₀ClN₃O₄Æ2(CO₂H)₂] C, H, N.

5.22. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-(3-

phenyl-isoxazol-5-yl)-propionic acid tert-butyl ester

(4A1B4C1) (5:1)

5.26. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionic acid tert-butyl

ester (4A5B4C1) (5:1)

The product was obtained as colourless oil (61%); IR

(neat, cm^ꢂ1) 1726 (CO₂Bu-t), 3398 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:36 (s, 9H, C(CH₃)₃), 1.42 (s,

9H, C(CH₃)₃), 2.23 (s, 3H, NCH₃), 2.25 (s, 3H, NCH₃),

2.45–2.80 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.01–3.07

(m, 4H, 2 ꢁ NCH₂), 5.24, 5.27 (d, 1H, J ¼ 7:8 Hz, CH),

5.31, 5.34 (d, 1H, J ¼ 7:8 Hz, CH), 6.55 (s, 1H, @CH),

6.58 (s, 1H, @CH), 7.42–7.44 (m, 6H, Ar–H), 7.75–7.81

(m, 4H, Ar–H); Mass (EI) m=z 401 (M^þ). Oxalate salt:

mp 190–192 °C; Anal. [C₂₂H₃₁N₃O₄Æ2(CO₂H)₂] C, H, N.

The product was obtained as white solid (59%), mp 105–

1

107 °C; IR (KBr, cm^ꢂ1) 1723 (CO₂Bu-t), 3485 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:36 (s, 9H, C(CH₃)₃),

1.45 (s, 9H, C(CH₃)₃), 1.46 (s, 9H, C(CH₃)₃), 2.27 (s, 6H,

2 ꢁ NCH₃), 2.47–2.81 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH),

3.03–3.07 (m, 4H, 2 ꢁ NCH₂), 5.31, 5.33 (d, 1H,

J ¼ 4:2 Hz, CH), 5.40, 5.42 (d, 1H, J ¼ 4:2 Hz, CH),

6.50 (s, 1H, @CH), 6.55 (s, 1H, @CH), 7.39, 7.43 (d, 4H,

J ¼ 8:4 Hz, Ar–H), 7.71, 7.75 (d, 4H, J ¼ 8:4 Hz, Ar–

H); ¹³C NMR (CDCl₃, 50.32 MHz) d ¼ 28:19, 28.34,

46.22, 47.76, 53.65, 55.26, 55.41, 56.69, 60.03, 69.49,

70.40, 82.37, 100.03, 100.58, 127.90, 128.03, 128.44,

129.54, 136.30, 161.53, 170.24, 174.06, 174.88; Mass

(FABþ) m=z 436 (M^þþ1). Oxalate salt: mp 184–185 °C;

Anal. [C₂₂H₃₀ClN₃O₄Æ2(CO₂H)₂] C, H, N.

5.23. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-(3-

p-tolyl-isoxazol-5-yl)-propionic acid-tert-butyl ester

(4A2B4C1) (5:1)

The product was obtained as white solid (54%), mp 100–

1

102 °C; IR (KBr, cm^ꢂ1) 1722 (CO₂Bu-t), 3394 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:36 (s, 9H, C(CH₃)₃),

1.42 (s, 9H, C(CH₃)₃), 2.28 (s, 3H, 2 ꢁ NCH₃), 2.39 (s,

6H, 2 ꢁ CH₃), 2.49–2.85 (m, 18H, 8 ꢁ NCH₂and

2 ꢁ CH), 2.98–3.28 (m, 4H, 2 ꢁ NCH₂), 5.24, 5.27 (d,

1H, J ¼ 7:8 Hz, CH), 5.38, 5.40 (d, 1H, J ¼ 7:8 Hz,

CH), 6.52 (s, 1H, @CH), 6.54 (s, 1H, @CH), 7.21, 7.25

(d, 4H, J ¼ 8:0 Hz, Ar–H), 7.66, 7.70 (d, 4H, J ¼ 8:0 Hz,

Ar–H); Mass (EI) m=z 415 (M^þ). Oxalate salt: mp. 176–

178 °C; Anal. [C₂₃H₃₃N₃O₄Æ2(CO₂H)₂ÆH₂O] C, H, N.

5.27. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-(4-methyl-piperazin-1-ylmethyl)-propionic acid tert-

butyl ester (4A6B4C1) (3:1)

The product was obtained as white solid (61%), mp 105–

1

107 °C; IR (KBr, cm^ꢂ1) 1721 (CO₂Bu-t), 3402 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:37 (s, 9H, C(CH₃)₃),

1.46 (s, 9H, C(CH₃)₃), 2.29 (s, 6H, 2 ꢁ NCH₃), 2.39–2.81

(m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.05–3.09 (m, 4H,

2 ꢁ NCH₂), 5.26, 5.29 (d, 1H, J ¼ 7:2 Hz, CH), 5.40,

5.42 (d, 1H, J ¼ 7:2 Hz, CH), 6.70 (s, 1H, @CH), 6.72 (s,

1H, @CH), 7.35, 7.39 (dd, 4H, J₁¼ 2:0 Hz, J₂¼ 8:4 Hz,

Ar–H), 7.50–7.51 (d, 2H, J ¼ 1:6 Hz, Ar–H), 7.65, 7.69

(d, 2H, J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 480.80

5.24. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-(4-methyl-piperazin-1-ylmethyl)-propionic acid-tert-

butyl ester (4A3B4C1) (5:1)

The product was obtained as white solid (58%), mp 135–

1

137 °C; IR (KBr, cm^ꢂ1) 1728 (CO₂Bu-t), 3398 (OH); H

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2067

(M^þþ1). Oxalate salt: mp 191–192 °C; Anal.

[C₂₂H₂₉Cl₂N₃O₄Æ2(CO₂H)₂] C, H, N.

7.72–7.76 (m, 2H, Ar–H); Mass (FABþ) m=z 361

(M^þþ1). Oxalate salt: mp 156–158 °C; Anal.

[C₁₈H₂₁ClN₄O₂Æ2(CO₂H)₂] C, H, N.

5.28. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-(3-

phenyl-isoxazol-5-yl)-propionitrile (4A1B5C1) (3:1)

5.32. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionitrile (4A5B5C1)

(3:1)

The product was obtained as yellow oil (51%); IR (neat,

cm^ꢂ1) 2256 (CN), 3390 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:28 (s, 3H, NCH₃), 2.29 (s, 3H, NCH₃),

2.39–2.98 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.29–3.34

(m, 4H, 2 ꢁ NCH₂), 5.27, 5.30 (m, 2H, 2 ꢁ CH), 6.70 (s,

1H, @CH), 6.75 (s, 1H, @CH), 7.44–7.47 (m, 6H, Ar–

H), 7.78–7.82 (m, 4H, Ar–H); ¹³C NMR (CDCl₃,

50.32 MHz) d ¼ 35:12, 35.92, 46.13, 53.52, 53.93, 55.22,

56.75, 57.14, 66.55, 67.66, 100.96, 118.51, 119.13,

127.24, 128.90, 129.41, 130.70, 162.90, 172.24, 172.47;

Mass (EI) m=z 326 (M^þ). Oxalate salt: mp 169–170 °C;

Anal. [C₁₈H₂₄N₄O₂Æ2(CO₂H)₂] C, H, N.

The product was obtained as yellow oil (49%); IR (neat,

cm^ꢂ1) 2257 (CN), 3439 (OH); ¹H NMR (CDCl₃,

300 MHz) d ¼ 2:29 (s, 3H, NCH₃), 2.31 (s, 3H, NCH₃),

2.50–2.86 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.04–3.16

(m, 4H, 2 ꢁ NCH₂), 5.28, 5.29 (d, 1H, J ¼ 3:6 Hz, CH),

5.43, 5.44 (d, 1H, J ¼ 3:6 Hz, CH), 6.86 (s, 1H, @CH),

6.90 (s, 1H, @CH), 7.48–7.51 (d, 4H, J ¼ 8:4 Hz, Ar–H),

7.81-7.84 (d, 4H, J ¼ 8:4 Hz, Ar–H); Mass (FABþ) m=z

361 (M^þþ1). Oxalate salt: mp 180–181 °C; Anal.

[C₁₈H₂₁ClN₄O₂Æ2(CO₂H)₂] C, H, N.

5.29. 3-Hydroxy-2-(4-methyl-piperazin-1-ylmethyl)-3-(3-

p-tolyl-isoxazol-5-yl)-propionitrile (4A2B5C1) (3:1)

5.33. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-3-hydr-

oxy-2-(4-methyl-piperazin-1-ylmethyl)-propionitrile

(4A6B5C1) (3:1)

The product was obtained as yellow oil (50%); IR (neat,

cm^ꢂ1) 2248 (CN), 3354 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:28 (s, 3H, NCH₃), 2.29 (s, 3H, NCH₃),

2.40 (s, 6H, 2 ꢁ CH₃), 2.50–3.04 (m, 18H, 8 ꢁ NCH₂and

2 ꢁ CH), 3.29–3.34 (m, 4H, 2 ꢁ NCH₂), 5.25–5.28 (m,

2H, 2 ꢁ CH), 6.67 (s, 1H, @CH), 6.72 (s, 1H, @CH),

7.25. 7.29 (d, 4H, J ¼ 8:0 Hz, Ar–H), 7.68, 7.72 (m, 4H,

J ¼ 8:0 Hz, Ar–H); Mass (EI) m=z 340 (M^þ). Oxalate

salt: mp 180–182 °C; Anal. [C₁₉H₂₄N₄O₂Æ2(CO₂-

H)₂ÆH₂O] C, H, N.

The product was obtained as yellow oil (47%); IR (neat,

cm^ꢂ1) 2251 (CN), 3390 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:29 (s, 6H, 2 ꢁ NCH₃), 2.44–2.96 (m,

18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.31–3.36 (m, 4H,

2 ꢁ NCH₂), 5.29–5.31 (m, 2H, 2 ꢁ CH), 6.86 (s, 1H,

@CH), 6.90 (s, 1H, @CH), 7.33, 7.37 (dd, 4H,

J₁¼ 2:0 Hz, J₂¼ 8:4 Hz, Ar–H), 7.52, 7.53 (d, 2H,

J ¼ 1:6 Hz, Ar–H), 7.68, 7.72 (d, 2H, J ¼ 8:4 Hz, Ar–

H); Mass (FABþ) m=z 395 (M^þþ1). Oxalate salt: mp

163–164 °C; Anal. [C₁₈H₂₀Cl₂N₄O₂Æ2(CO₂H)₂] C, H, N.

5.30. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-(4-methyl-piperazin-1-ylmethyl)-propionitrile

(4A3B5C1) (3:1)

5.34. 2-(4-Acetyl-piperazin-1-ylmethyl)-3-hydroxy-3-

(3-phenyl-isoxazol-5-yl)-propionic acid ethyl ester

(4A1B2C2) (5:1)

The product was obtained as yellow oil (65%); IR (neat,

cm^ꢂ1) 2247 (CN), 3354 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:28 (s, 3H, NCH₃), 2.29 (s, 3H, NCH₃),

2.43–2.99 (m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.29–3.36

(m, 4H, 2 ꢁ NCH₂), 5.11 (s, 4H, 2 ꢁ OCH₂O), 5.39–5.45

(m, 2H, 2 ꢁ CH), 6.64 (s, 1H, @CH), 6.67 (s, 1H, @CH),

7.25. 7.29 (d, 4H, J ¼ 8:0 Hz, Ar–H), 7.31–7.45 (m, 10H,

Ar–H), 7.68, 7.72 (m, 4H, J ¼ 8:0 Hz, Ar–H); Mass

(ESþ) m=z 433.80 (M^þþ1), 455.53 (M^þþNa). Oxalate

salt: mp 119–121 °C; Anal. [C₂₅H₂₈N₄O₃Æ2(CO₂H)₂] C,

H, N.

The product was obtained as pale yellow oil (59%): IR

1

(neat, cm^ꢂ1) 1731 (CO₂Et and COMe), 3320 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:16–1:29 (m, 2t merged,

6H, J ¼ 7:0 Hz, 2 ꢁ CH₃), 2.04 (s, 3H, COCH₃), 2.08 (s,

3H, COCH₃), 2.52–2.65 (m, 8H, 4 ꢁ NCH₂), 2.80–3.26

(m, 4H, NCH₂and 2 ꢁ CH), 3.47 (t, 4H, J ¼ 4:6 Hz,

2 ꢁ NCH₂), 3.63 (t, 4H, J ¼ 4:6 Hz, 2 ꢁ NCH₂), 4.05–

4.16 (m, 2q merged, 4H, 2 ꢁ OCH₂), 5.30–5.36 (m, 2H,

2 ꢁ CH), 6.58 (s, 1H, @CH), 7.43–7.46 (m, 6H, Ar–H),

7.77–7.81 (m, 4H, Ar–H); Mass (ESþ) m=z 402.47

(M^þþ1), 423.80 (M^þþNa). Oxalate salt: mp 90–92 °C;

Anal. [C₂₁H₂₇N₃O₅Æ2(CO₂H)₂] C, H, N.

5.31. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

(4-methyl-piperazin-1-ylmethyl)-propionitrile (4A4B5C1)

(3:1)

5.35. 2-(4-Acetyl-piperazin-1-ylmethyl)-3-[3-(4-benzyl-

oxy-phenyl)-isoxazol-5-yl]-3-hydroxy-propionic acid

ethyl ester (4A3B2C2) (6:1)

The product was obtained as yellow oil (47%); IR (neat,

cm^ꢂ1) 2257 (CN), 3390 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:29, 2.31 (2s, 6H, 2 ꢁ NCH₃), 2.45–2.85

(m, 18H, 8 ꢁ NCH₂and 2 ꢁ CH), 3.08–3.15 (m, 4H,

2 ꢁ NCH₂), 5.28–5.31 (m, 2H, 2 ꢁ CH), 6.86 (s, 1H,

@CH), 6.90 (s, 1H, @CH), 7.35–7.52 (m, 6H, Ar–H),

The product was obtained as pale yellow oil (53%): IR

1

(neat, cm^ꢂ1) 1728 (CO₂Et and COMe), 3401 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:19–1:29 (m, 2t merged,

6H, J ¼ 7:0 Hz, 2 ꢁ CH₃), 2.05 (s, 3H, COCH₃), 2.08 (s,

2068

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

3H, COCH₃), 2.52–2.66 (m, 8H, 4 ꢁ NCH₂), 2.71–2.85

(m, 4H, 2 ꢁ NCH₂), 2.97–3.14 (m, 2H, 2 ꢁ CH), 3.48 (t,

4H, J ¼ 4:8 Hz, 2 ꢁ NCH₂), 3.62 (t, 4H, J ¼ 4:8 Hz,

2 ꢁ NCH₂), 4.02–4.15 (m, 2q merged, 4H, J ¼ 7:0 Hz, 2

ꢁ OCH₂), 5.12 (s, 4H, 2 ꢁ OCH₂O), 5.32, 5.35 (d, 2H,

J ¼ 7:2 Hz, CH), 6.53 (s, 1H, @CH), 7.02, 7.06 (d, 4H,

J ¼ 8:6 Hz, Ar–H), 7.33–7.46 (m, 10H, Ar–H), 7.70,

7.74 (d, 4H, J ¼ 8:6 Hz, Ar–H); Mass (FABþ) m=z 508

(M^þþ1). Oxalate salt: mp 168–170 °C; Anal.

[C₂₈H₃₃N₃O₆Æ2(CO₂H)₂] C, H, N.

CH), 6.70 (s, 1H, @CH), 6.73 (s, 1H, @CH), 7.32, 7.36

(dd, 2H, J ¼ 1:8 Hz, J ¼ 8:4 Hz, Ar–H), 7.51, 7.52 (d,

2H, J ¼ 1:6 Hz, Ar–H), 7.66, 7.70 (d, 2H, J ¼ 8:4 Hz,

Ar–H); Mass (ESþ) m=z 470.40 (M^þþ1), 492.00

(M^þþNa). Oxalate salt: mp 85–88 °C; Anal.

[C₂₁H₂₅Cl₂N₃O₆Æ2(CO₂H)₂] C, H, N.

5.39. 3-Hydroxy-2-[4-(4-methoxy-phenyl)-piperazin-1-

ylmethyl]-3-(3-phenyl-isoxazol-5-yl)-propionic acid ethyl

ester (4A1B2C3) (5:1)

5.36. 2-(4-Acetyl-piperazin-1-ylmethyl)-3-[3-(2-chloro-

phenyl)-isoxazol-5-yl]-3-hydroxy-propionic acid ethyl

ester (4A4B2C2) (6:1)

The product was obtained as pale yellow oil (59%): IR

(neat, cm^ꢂ1) 1729 (CO₂Et), 3320 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:15–1:27 (m, 2t merged,

6H, J ¼ 7:0 Hz, 2 ꢁ CH₃), 2.52–2.65 (m, 8H,

4 ꢁ NCH₂), 2.67–2.93 (m, 12H, 6 ꢁ NCH₂), 3.09–3.21

(m, 4 ꢁ NCH₂and 2 ꢁ CH), 3.75 (s, 3H, OCH₃), 3.77 (s,

3H, OCH₃), 4.13 (m, 2q merged, 4H, 2 ꢁ OCH₂), 5.34,

5.38 (d, 1H, J ¼ 7:4 Hz, CH), 5.41, 5.45 (d, 1H,

J ¼ 7:4 Hz, CH), 6.56 (s, 1H, @CH), 6.59 (s, 1H, @CH),

6.81–6.91 (m, 8H, Ar–H), 7.43–7.46 (m, 6H, Ar–H),

7.77–7.81 (m, 4H, Ar–H); Mass (FAB+) m=z 466

(M^þþ1). Oxalate salt: mp 143–145 °C; Anal.

[C₂₆H₃₁N₃O₅Æ2(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (57%): IR

1

(neat, cm^ꢂ1) 1731 (CO₂Et and COMe), 3443 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:19–1:30 (m, 2t merged,

6H, J ¼ 7:0 Hz, 2 ꢁ CH₃), 1.96 (s, 3H, COCH₃), 2.02 (s,

3H, COCH₃), 2.38–2.67 (m, 8H, 4 ꢁ NCH₂), 2.74–2.90

(m, 4H, 2 ꢁ NCH₂), 2.92–3.19 (m, 2H, 2 ꢁ CH), 3.46 (t,

4H, J ¼ 4:6 Hz, 2 ꢁ NCH₂), 3.63 (t, 4H, J ¼ 4:6 Hz,

2 ꢁ NCH₂), 4.02–4.15 (m, 2q merged, 4H, J ¼ 7:0 Hz,

2 ꢁ OCH₂), 5.31–5.38 (m, 2H, CH), 6.53 (s, 1H, @CH),

6.56 (s, 1H, @CH), 7.34–7.51 (m, 6H, Ar–H), 7.72–7.76

(m, 2H, Ar–H); Mass (ESþ) m=z 436.67 (M^þþ1), 458.67

(M^þþNa). Oxalate salt: mp 126–128 °C; Anal.

[C₂₁H₂₆ClN₃O₆Æ2(CO₂H)₂] C, H, N.

5.40. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-[4-(4-methoxy-phenyl)-piperazin-1-ylmethyl]-propionic

acid ethyl ester (4A3B2C3) (5:1)

5.37. 2-(4-Acetyl-piperazin-1-ylmethyl)-3-[3-(4-chloro-

phenyl)-isoxazol-5-yl]-3-hydroxy-propionic acid ethyl

ester (4A5B2C2) (6:1)

The product was obtained as pale yellow oil (61%): IR

(neat, cm^ꢂ1) 1724 (CO₂Et), 3419 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:15–1:30 (m, 2t merged, 6H,

J ¼ 7:0 Hz, 2 ꢁ CH₃), 2.70–2.92 (m, 12H, 6 ꢁ NCH₂),

3.09–3.20 (m, 4 ꢁ NCH₂and 2 ꢁ CH), 3.76 (s, 3H,

OCH₃), 3.78 (s, 3H, OCH₃), 4.14 (m, 2q merged, 4H,

2 ꢁ OCH₂), 5.11 (s, 4H, 2 ꢁ OCH₂O), 5.34, 5.38 (d, 1H,

J ¼ 7:4 Hz, CH), 5.41, 5.45 (d, 1H, J ¼ 7:4 Hz, CH),

6.52 (s, 1H, @CH), 6.53 (s, 1H, @CH), 6.85–6.87 (m,

8H, Ar–H), 7.01, 7.05 (d, 4H, J ¼ 8:8 Hz, Ar–H),

7.32–7.45 (m, 10H, Ar–H), 7.71-7.75 (d, 4H, J ¼ 8:8 Hz,

Ar–H); Mass (FABþ) m=z 572 (M^þþ1). Oxalate salt:

mp 176–178 °C; Anal. [C₃₃H₃₇N₃O₆Æ2(CO₂H)₂] C, H,

N.

The product was obtained as pale yellow oil (55%): IR

1

(neat, cm^ꢂ1) 1731 (CO₂Et and COMe), 3444 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:16–1:29 (m, 2t merged,

6H, J ¼ 7:0 Hz, CH₃), 2.04 (s, 3H, COCH₃), 2.09 (s, 3H,

COCH₃), 2.52–2.67 (m, 8H, 4 ꢁ NCH₂), 2.74–2.90 (m,

4H, 2 ꢁ NCH₂), 2.99–3.26 (m, 2H, 2 ꢁ CH), 3.46 (t, 4H,

J ¼ 4:8 Hz, 2 ꢁ NCH₂), 3.63 (t, 4H, J ¼ 4:8 Hz,

2 ꢁ NCH₂), 4.08–4.18 (m, 2q merged, 4H, J ¼ 7:0 Hz,

2 ꢁ OCH₂), 5.33, 5.36 (d, 2H, J ¼ 7:2 Hz, 2 ꢁ CH), 6.53

(s, 1H, @CH), 6.56 (s, 1H, @CH), 7.41, 7.45 (d, 2H,

J ¼ 8:6 Hz, Ar–H), 7.71, 7.75 (d, 2H, J ¼ 8:6 Hz, Ar–

H); Mass (ESþ) m=z 458.00 (M^þþNa). Oxalate salt: mp

78–81 °C; Anal. [C₂₁H₂₆ClN₃O₅Æ2(CO₂H)₂] C, H, N.

5.41. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

[4-(4-methoxy-phenyl)-piperazin-1-ylmethyl]-propionic

acid ethyl ester (4A4B2C3) (5:1)

5.38. 2-(4-Acetyl-piperazin-1-ylmethyl)-3-[3-(2,4-

dichloro-phenyl)-isoxazol-5-yl]-3-hydroxy-propionic

acid ethyl ester (4A6B2C2) (3:1)

The product was obtained as pale yellow oil (58%): IR

(neat, cm^ꢂ1) 1722 (CO₂Et), 3401 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:15–1:29 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.70–2.93 (m, 12H, 6 ꢁ NCH₂),

3.09–3.20 (m, 4 ꢁ NCH₂and 2 ꢁ CH), 3.76 (s, 3H,

OCH₃), 3.78 (s, 3H, OCH₃), 4.08–4.19 (m, 2q merged,

4H, 2 ꢁ OCH₂), 5.34, 5.38 (d, 1H, J ¼ 7:4 Hz, CH), 5.41,

5.45 (d, 1H, J ¼ 7:4 Hz, CH), 6.56 (s, 1H, @CH), 6.57 (s,

1H, @CH), 6.56 (s, 1H, @CH), 6.82–6.88 (m, 8H, Ar–

H), 7.44–7.68 (m, 8H, Ar–H); Mass (ESþ) m=z 500.38

(M^þþ1), 522.67 (M^þþNa). Oxalate salt: mp 120–

121 °C; Anal. [C₂₆H₃₀ClN₃O₅Æ2(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (52%): IR

1

(neat, cm^ꢂ1) 1728 (CO₂Et and COMe), 3394 (OH); H

NMR (CDCl₃, 200 MHz) d ¼ 1:16–130 (m, 6H,

2 ꢁ CH₃), 2.09 (s, 3H, COCH₃), 2.13 (s, 3H, COCH₃),

2.50–2.58 (m, 8H, 4 ꢁ NCH₂), 2.63–2.68 (m, 4H,

2 ꢁ NCH₂), 3.09–3.15 (m, 2H, 2 ꢁ CH), 3.48 (t, 4H,

J ¼ 4:8 Hz, 2 ꢁ NCH₂), 3.64 (t, 4H, J ¼ 4:8 Hz,

2 ꢁ NCH₂), 4.12–4.21 (m, 4H, 2 ꢁ OCH₂), 5.35, 5.38 (d,

2H, J ¼ 7:4 Hz, CH), 5.42, 5.45 (d, 2H, J ¼ 7:4 Hz,

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2069

5.42. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

[4-(4-methoxy-phenyl)-piperazin-1-ylmethyl]-propionic

acid ethyl ester (4A5B2C3) (5:1)

(CDCl₃, 200 MHz) d ¼ 1:16–1:27 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.67–2.93 (m, 6H, 3 ꢁ NCH₂),

3.11–3.21 (m, 5H, 2 ꢁ NCH₂and CH), 4.08–4.16 (m, 2q

merged, 4H, 2 ꢁ OCH₂), 5.12 (s, 2H, OCH₂), 5.34, 5.38

(d, 1H, J ¼ 7:6 Hz, CH), 6.54 (s, 1H, @CH), 6.82–7.06

(m, 7H, Ar–H), 7.33–7.46 (m, 4H, Ar–H), 7.71, 7.75 (d,

2H, J ¼ 8:6 Hz, Ar–H); ¹³C NMR (CDCl₃, 50.32 MHz)

d ¼ 14:54, 46.89, 50.59, 52.69, 53.82, 59.32, 70.26, 70.48,

100.04, 115.69, 116.25, 114.47, 118.61, 122.18, 127.88,

128.53, 128.68, 129.06, 137.02, 155.45, 160.22, 160.64,

162.20, 171.81, 173.27; Mass (ESMS) m=z 559.67

(M^þþ1), 582.73 (M^þþNa). Oxalate salt: mp 126–

128 °C; Anal. [C₃₂H₃₄FN₃O₅Æ2(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (59%): IR

(neat, cm^ꢂ1) 1731 (CO₂Et), 3373 (OH); ¹H NMR (CDCl₃,

200 MHz) d ¼ 1:15–1:29 (m, 2t merged, 6H, J ¼ 7:2 Hz,

2 ꢁ CH₃), 2.70–2.93 (m, 12H, 6 ꢁ NCH₂), 3.09–3.20 (m,

4 ꢁ NCH₂and 2 ꢁ CH), 3.76 (s, 3H, OCH₃), 3.78 (s, 3H,

OCH₃), 4.06–4.17 (m, 2q merged, 4H, 2 ꢁ OCH₂), 5.34,

5.38 (d, 1H, J ¼ 7:4 Hz, CH), 5.41, 5.45 (d, 1H,

J ¼ 7:4 Hz, CH), 6.56 (s, 1H, @CH), 6.57 (s, 1H, @CH),

6.85–6.91 (m, 8H, Ar–H), 7.40, 7.44 (d, 4H, J ¼ 8:6 Hz,

Ar–H), 7.71–7.75 (d, 4H, J ¼ 8:6 Hz, Ar–H); Mass (ESþ)

m=z 500.67 (M^þþ1), 522.67 (M^þþNa). Oxalate salt: mp

163–164 °C; Anal. [C₂₆H₃₀ClN₃O₅Æ2(CO₂H)₂] C, H, N.

5.46. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-[4-(4-ﬂuoro-

phenyl)-piperazin-1-ylmethyl]-3-hydroxy-propionic acid

ethyl ester (4A4B2C4) (6:1)

5.43. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-3-hydr-

oxy-2-[4-(4-methoxy-phenyl)-piperazin-1-ylmethyl]-prop-

ionic acid ethyl ester (4A6B2C3) (5:1)

The product was obtained as pale yellow oil (59%): IR

(neat, cm^ꢂ1) 1736 (CO₂Et), 3435 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:15–1:28 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.66–2.93 (m, 12H, 6 ꢁ NCH₂),

3.13–3.21 (m, 10H, 4 ꢁ NCH₂and 2 ꢁ CH), 4.08–4.17

(m, 2q merged, 4H, 2 ꢁ OCH₂), 5.33, 5.36 (d, 1H,

J ¼ 7:6 Hz, CH), 5.41, 5.44 (d, 1H, J ¼ 7:6 Hz, CH),

6.52 (s, 1H, @CH), 6.56 (s, 1H, @CH), 6.81–7.02 (m,

8H, Ar–H), 7.43–7.67 (m, 8H, Ar–H); Mass (ESþ) m=z

488.87 (M^þþ1). Oxalate salt: mp 149–150 °C; Anal.

[C₂₅H₂₇ClFN₃O₄Æ2(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (59%): IR

(neat, cm^ꢂ1) 1730 (CO₂Et), 3389 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:16–1:28 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.68–2.94 (m, 12H, 6 ꢁ NCH₂),

3.09–3.22 (m, 4 ꢁ NCH₂and 2 ꢁ CH), 3.77 (s, 3H,

OCH₃), 3.78 (s, 3H, OCH₃), 4.10–4.19 (m, 2q merged,

4H, 2 ꢁ OCH₂), 5.35, 5.39 (d, 1H, J ¼ 7:4 Hz, CH), 5.42,

5.46 (d, 1H, J ¼ 7:4 Hz, CH), 6.73 (s, 1H, @CH), 6.74 (s,

1H, @CH), 6.85–6.87 (m, 8H, Ar–H), 7.31, 7.34 (dd, 4H,

J₁¼ 2:0 Hz, J₂¼ 8:4 Hz, Ar–H), 7.50, 7.51 (d, 2H,

J ¼ 1:8 Hz, Ar–H), 7.66, 7.70 (d, 2H, J ¼ 8:4 Hz, Ar–

H); ¹³C NMR (CDCl₃, 50.32 MHz) d ¼ 14:43, 45.54,

46.94, 51.04, 53.96, 56.62, 59.62, 59.61, 61.76, 70.34,

103.34, 114.94, 118.91, 127.30, 127.95, 130.68, 132.13,

134.03, 136.69, 145.55, 153.64, 160.35, 171.14, 173.04;

Mass (ESþ) m=z 534.53 (M^þþ1), 556.80 (M^þþNa).

Oxalate salt: mp 95–98 °C; Anal. [C₂₆H₂₉Cl₂N₃

O₅Æ2(CO₂H)₂] C, H, N.

5.47. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-2-[4-(4-ﬂuoro-

phenyl)-piperazin-1-ylmethyl]-3-hydroxy-propionic acid

ethyl ester (4A5B2C4) (6:1)

The product was obtained as pale yellow oil (61%): IR

(neat, cm^ꢂ1) 1739 (CO₂Et), 3445 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:16–1:27 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.67–2.93 (m, 12H, 6 ꢁ NCH₂),

3.12–3.20 (m, 10H, 4 ꢁ NCH₂and 2 ꢁ CH), 4.13 (m, 2q

merged, 4H, 2 ꢁ OCH₂), 5.34, 5.37 (d, 1H, J ¼ 7:6 Hz,

CH), 5.41, 5.44 (d, 1H, J ¼ 7:6 Hz, CH), 6.53 (s, 1H,

@CH), 6.56 (s, 1H, @CH), 6.84–7.01 (m, 8H, Ar–H),

7.40, 7.44 (d, 4H, J ¼ 8:6 Hz, Ar–H), 7.71, 7.75 (d, 4H,

J ¼ 8:6 Hz, Ar–H); Mass (ESþ) m=z 488.00 (M^þþ1),

509.93 (M^þþNa). Oxalate salt: mp 180–182 °C; Anal.

[C₂₅H₂₇ClFN₃O₄Æ2(CO₂H)₂] C, H, N.

5.44. 2-[4-(4-Fluoro-phenyl)-piperazin-1-ylmethyl]-3-

hydroxy-3-(3-phenyl-isoxazol-5-yl)-propionic acid

ethyl ester (4A1B2C4) (3:1)

The product was obtained as pale yellow oil (58%): IR

(neat, cm^ꢂ1) 1730 (CO₂Et), 3401 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:16–1:27 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.67–2.93 (m, 12H, 6 ꢁ NCH₂),

3.12–3.21 (m, 10H, 4 ꢁ NCH₂and 2 ꢁ CH), 4.09–4.16

(m, 2q merged, 4H, 2 ꢁ OCH₂), 5.35, 5.38 (d, 1H,

J ¼ 7:6 Hz, CH), 5.42, 5.45 (d, 1H, J ¼ 7:6 Hz, CH), 6.57

(s, 1H, @CH), 6.59 (s, 1H, @CH), 6.82–7.01 (m, 8H, Ar–

H), 7.43–7.46 (m, 6H, Ar–H), 7.77–7.82 (m, 4H, Ar–H);

Mass (ESþ) m=z 476.07 (M^þþNa). Oxalate salt: mp 146–

148 °C; Anal. C₂₅H₂₈FN₃O₄Æ2(CO₂H)₂] C, H, N.

5.48. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-2-[4-(4-

ﬂuoro-phenyl)-piperazin-1-ylmethyl]-3-hydroxy-propionic

acid ethyl ester (4A6B2C4) (6:1)

The product was obtained as pale yellow oil (59%): IR

(neat, cm^ꢂ1) 1729 (CO₂Et), 3383 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:16–1:28 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.68–2.94 (m, 12H, 6 ꢁ NCH₂),

3.12–3.22 (m, 10H, 4 ꢁ NCH₂and 2 ꢁ CH), 4.13 (m, 2q

merged, 4H, 2 ꢁ OCH₂), 5.36, 5.39 (d, 1H, J ¼ 7:6 Hz,

CH), 5.42, 5.45 (d, 1H, J ¼ 7:6 Hz, CH), 6.71 (s, 1H,

@CH), 6.73 (s, 1H, @CH), 6.83–7.01 (m, 8H, Ar–H),

5.45. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-[4-(4-

ﬂuoro-phenyl)-piperazin-1-ylmethyl]-3-hydroxy-propionic

acid ethyl ester (4A3B2C4) (5:1)

The product was obtained as pale yellow oil (51%): IR

(neat, cm^ꢂ1) 1729 (CO₂Et), 3422 (OH); ¹H NMR

2070

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

7.31, 7.36 (dd, 4H, J₁¼ 2:0 Hz, J₂¼ 8:4 Hz, Ar–H),

7.50, 7.51 (d, 2H, J ¼ 1:8 Hz, Ar–H), 7.66–7.70 (d, 2H,

J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 522.07 (M^þþ1),

544.33 (M^þþNa). Oxalate salt: mp 167–168 °C; Anal.

[C₂₅H₂₆Cl₂FN₃O₄Æ2(CO₂H)₂] C, H, N.

5.52. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

[4-(3-phenyl-allyl)-piperazin-1-ylmethyl]-propionic acid

ethyl ester (4A5B2C5) (6:1)

The product was obtained as pale yellow oil (58%): IR

(neat, cm^ꢂ1) 1730 (CO₂Et), 3328 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:13–1:28 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.57–2.82 (m, 22H, 10 ꢁ NCH₂

and 2 ꢁ CH), 3.14–3.17 (m, 4H, 2 ꢁ NCH₂), 4.07–4.14

(m, 2q merged, 4H, 2 ꢁ OCH₂), 5.30, 5.33 (d, 1H,

J ¼ 7:6 Hz, CH), 5.28–5.38 (m, 2H, 2 ꢁ CH), 6.12–6.29

(m, 2t merged, 2H, 2 ꢁ @CH), 6.48 (s, 2H, 2 ꢁ @CH),

6.54 (s, 1H, @CH), 6.55 (s, 1H, @CH), 7.22–7.43 (m,

14H, Ar–H), 7.70–7.74 (d, 4H, J ¼ 8:4 Hz, Ar–H); Mass

(FABþ) m=z 510 (M^þþ1). Oxalate salt: mp 207–209 °C;

Anal. [C₂₈H₃₂ClN₃O₄Æ2(CO₂H)₂] C, H, N.

5.49. 3-Hydroxy-2-[4-(3-phenyl-allyl)-piperazin-1-yl-

methyl]-3-(3-phenyl-isoxazol-5-yl)-propionic acid ethyl

ester (4A1B2C5) (6:1)

The product was obtained as pale yellow oil (58%): IR

(neat, cm^ꢂ1) 1731 (CO₂Et), 3381 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:14–1:27 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.44–2.88 (m, 22H, 10 ꢁ NCH₂

and 2 ꢁ CH), 3.15–3.19 (m, 4H, 2 ꢁ NCH₂), 4.10 (m, 2q

merged, 4H, 2 ꢁ OCH₂), 5.31, 5.35 (d, 1H, J ¼ 7:0 Hz,

CH), 5.38, 5.41 (d, 1H, J ¼ 7:0 Hz, CH), 6.19–6.48 (m,

2t merged, 2H, J ¼ 8:4 Hz, 2 ꢁ @CH), 6.48 (s, 2H,

2 ꢁ @CH), 6.57 (s, 1H, @CH), 6.58 (s, 1H, @CH), 7.22–

7.45 (m, 16H, Ar–H), 7.77–7.81 (m, 4H, Ar–H); Mass

(ESþ) m=z 476.47 (M^þþ1), 498.07 (M^þþNa). Oxalate

salt: mp 192–194 °C (dec); Anal. [C₂₈H₃₃N₃O₄Æ2(CO₂-

H)₂] C, H, N.

5.53. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-[4-(3-phenyl-allyl)-piperazin-1-ylmethyl]-propionic acid

ethyl ester (4A6B2C5) (6:1)

The product was obtained as pale yellow oil (58%): IR

(neat, cm^ꢂ1) 1730 (CO₂Et), 3358 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:14–1:28 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.57–2.87 (m, 22H, 10 ꢁ NCH₂

and 2 ꢁ CH), 3.14–3.17 (m, 4H, 2 ꢁ NCH₂), 4.05–4.21

(m, 2q merged, 4H, 2 ꢁ OCH₂), 5.32, 5.36 (d, 1H,

J ¼ 7:6 Hz, CH), 5.40, 5.44 (d, 1H, J ¼ 7:6 Hz, CH),

5.28–5.38 (m, 2H, 2 ꢁ CH), 6.19–6.30 (m, 2t merged,

2H, 2 ꢁ @CH), 6.48 (s, 2H, 2 ꢁ @CH), 6.69 (s, 1H,

@CH), 6.71 (s, 1H, @CH), 7.22–7.39 (m, 12H, Ar–H),

7.50, 7.51 (d, 2H, J ¼ 1:8 Hz, Ar–H), 7.66-7.70 (d, 2H,

J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 544.60 (M^þþ1),

566.93 (M^þþNa). Oxalate salt: mp 207–209 °C; Anal.

[C₂₈H₃₁Cl₂N₃O₄Æ2(CO₂H)₂] C, H, N.

5.50. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-3-hydroxy-

2-[4-(3-phenyl-allyl)-piperazin-1-ylmethyl]-propionic acid

ethyl ester (4A3B2C5) (6:1)

The product was obtained as pale yellow oil (58%): IR

(neat, cm^ꢂ1) 1731 (CO₂Et), 3381 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:14–1:30 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.57–2.88 (m, 22H, 10 ꢁ NCH₂

and 2 ꢁ CH), 3.11–3.17 (m, 4H, 2 ꢁ NCH₂), 4.05–4.17

(m, 2q merged, 4H, 2 ꢁ OCH₂), 5.11 (s, 4H,

2 ꢁ OCH₂O), 5.30, 5.33 (d, 1H, J ¼ 7:6 Hz, CH), 5.35,

5.38 (d, 1H, J ¼ 7:6 Hz, CH), 6.19–6.30 (m, 2t merged,

2H, J ¼ 6:6 Hz, 2 ꢁ @CH), 6.48 (s, 2H, 2 ꢁ @CH), 6.52

(s, 1H, @CH), 6.57 (s, 1H, @CH), 7.01, 7.05 (d, 4H,

J ¼ 8:4 Hz, Ar–H), 7.22–7.45 (m, 20H, Ar–H), 7.70–

7.74 (d, 4H, J ¼ 8:4 Hz, Ar–H); Mass (FABþ) m=z 582

(M^þþ1). Oxalate salt: mp 205–206 °C; Anal.

[C₃₅H₃₉N₃O₅Æ2(CO₂H)₂] C, H, N.

5.54. 2-(4-Benzyl-piperidin-1-ylmethyl)-3-hydroxy-3-

(3-phenyl-isoxazol-5-yl)-propionic acid ethyl ester

(4A1B2C6)

The product was obtained as pale yellow oil (51%): IR

(neat, cm^ꢂ1) 1732 (CO₂Et), 3384 (OH); Mass (ESþ) m=z

449.80 (M^þþ1), 471.47 (M^þþNa). Oxalate salt: mp 103–

104 °C. Anal. [C₂₇H₃₂N₂O₄Æ(CO₂H)₂] C, H, N.

5.51. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-3-hydroxy-2-

[4-(3-phenyl-allyl)-piperazin-1-ylmethyl]-propionic acid

ethyl ester (4A4B2C5) (6:1)

5.55. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-benz-

yl-piperidin-1-ylmethyl)-3-hydroxy-propionic acid ethyl

ester (4A3B2C6)

The product was obtained as pale yellow oil (62%): IR

(neat, cm^ꢂ1) 1735 (CO₂Et), 3445 (OH); ¹H NMR

(CDCl₃, 300 MHz) d ¼ 1:16–1:27 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.50–2.91 (m, 22H, 10 ꢁ NCH₂

and 2 ꢁ CH), 3.13–3.17 (m, 4H, 2 ꢁ NCH₂), 4.07–4.14

(m, 2q merged, 4H, 2 ꢁ OCH₂), 5.31, 5.34 (d, 1H,

J ¼ 7:6 Hz, CH), 5.28–5.38 (m, 2H, 2 ꢁ CH), 6.12–6.30

(m, 2t merged, 2H, 2 ꢁ @CH), 6.48 (s, 2H, 2 ꢁ @CH),

6.55 (s, 1H, @CH), 6.60 (s, 1H, @CH), 6.75–6.85 (m,

8H, Ar–H), 7.30–7.67 (m, 18H, Ar–H); Mass (ESþ) m=z

511.00 (M^þþ1). Oxalate salt: mp 197–199 °C; Anal.

[C₂₈H₃₂ClN₃O₄Æ2(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (56%): IR

(neat, cm^ꢂ1) 1730 (CO₂Et), 3418 (OH); Mass (ESþ) m=z

449.80 (M^þþ1), 471.47 (M^þþNa). Oxalate salt: mp 103–

104 °C. Anal. [C₂₇H₃₂N₂O₄Æ(CO₂H)₂] C, H, N.

5.56. 2-(4-Benzyl-piperidin-1-ylmethyl)-3-[3-(2-chloro-

phenyl)-isoxazol-5-yl]-3-hydroxy-propionic acid ethyl

ester (4A4B2C6)

The product was obtained as pale yellow oil (54%): IR

(neat, cm^ꢂ1) 1729 (CO₂Et), 3358 (OH); Mass (FAB+)

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2071

m=z 483 (M^þþ1). Oxalate salt: mp 97–98 °C. Anal.

[C₂₇H₃₁ClN₂O₄Æ(CO₂H)₂] C, H, N.

(CDCl₃, 200 MHz) d ¼ 1:00–1:19 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.51–3.15 (m, 14H, 6 ꢁ NCH₂

and 2 ꢁ CH), 3.72–3.80 (m, 2q merged, 4H, J ¼ 7:0 Hz,

2 ꢁ OCH₂), 5.30, 5.34 (d, 1H, J ¼ 7:0 Hz, CH), 5.38,

5.42 (d, 1H, J ¼ 7:0 Hz, CH), 6.47 (s, 1H, @CH), 6.55 (s,

1H, @CH), 7.46–7.68 (m, 8H, Ar–H); Mass (ESþ) m=z

381.80 (M^þþ1). Oxalate salt: mp 101–102 °C (dec);

Anal. [C₁₉H₂₅ClN₂O₄Æ(CO₂H)₂] C, H, N.

5.57. 2-(4-Benzyl-piperidin-1-ylmethyl)-3-[3-(4-chloro-

phenyl)-isoxazol-5-yl]-3-hydroxy-propionic acid ethyl

ester (4A5B2C6)

The product was obtained as pale yellow oil (55%): IR

(neat, cm^ꢂ1) 1729 (CO₂Et), 3380 (OH); Mass (ES+) m=z

471.73 (M^þþ 1). Oxalate salt: mp 150–153 °C. Anal.

[C₂₇H₃₁ClN₂O₄Æ(CO₂H)₂] C, H, N.

5.62. 3-[3-(4-Chloro-phenyl)-isoxazol-5-yl]-2-diethyl-

aminomethyl-3-hydroxy-propionic acid ethyl ester

(4A5B2C7) (2:1)

5.58. 2-(4-Benzyl-piperidin-1-ylmethyl)-3-[3-(2,4-

dichloro-phenyl)-isoxazol-5-yl]-3-hydroxy-propionic

acid ethyl ester (4A6B2C6)

The product was obtained as pale yellow oil (50%): IR

(neat, cm^ꢂ1) 1728 (CO₂Et), 3368 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:00–1:15 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.46–2.56 (m, 4H, 2 ꢁ NCH₂),

2.69–2.87 (m, 6H, 2 ꢁ NCH₂and 2 ꢁ CH), 3.09–3.19 (m,

4H, 2 ꢁ NCH₂), 3.72–3.79 (m, 2q merged, 4H,

J ¼ 7:0 Hz, 2 ꢁ OCH₂), 5.27, 5.31 (d, 1H, J ¼ 7:8 Hz,

CH), 5.41, 5.45 (d, 1H, J ¼ 7:8 Hz, CH), 6.46 (s, 1H,

@CH), 6.55 (s, 1H, @CH), 7.39, 7.43 (d, 4H, J ¼ 8:4 Hz,

Ar–H), 7.71, 7.75 (d, 4H, J ¼ 8:4 Hz, Ar–H); Mass

(FABþ) m=z 381 (M^þþ1). Oxalate salt: mp 150–152 °C

(dec); Anal. [C₁₉H₂₅ClN₂O₄Æ(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (54%): IR

(neat, cm^ꢂ1) 1725 (CO₂Et), 3420 (OH); Mass (FAB+)

m=z 505 (M^þþ 1). Oxalate salt: mp 95–98 °C. Anal.

[C₂₇H₃₀Cl₂N₂O₄Æ(CO₂H)₂] C, H, N.

5.59. 2-Diethylaminomethyl-3-hydroxy-3-(3-phenyl-iso-

xazol-5-yl)-propionic acid ethyl ester (4A1B2C7) (2:1)

The product was obtained as pale yellow oil (52%): IR

(neat, cm^ꢂ1) 1732 (CO₂Et), 3381 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 1:04–1:19 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.46–2.87 (m, 10H, 4 ꢁ NCH₂and

2 ꢁ CH), 2.73–2.87 (m, 4H, 2 ꢁ NCH₂), 4.04–4.12 (m, 2q

merged, 4H, J ¼ 7:0 Hz, 2 ꢁ OCH₂), 5.27, 5.31 (d, 1H,

J ¼ 7:0 Hz, CH), 5.38, 5.41 (d, 1H, J ¼ 7:0 Hz, CH),

6.46 (s, 1H, @CH), 6.58 (s, 1H, @CH), 7.42–7.45 (m,

6H, Ar–H), 7.77–7.81 (m, 4H, Ar–H); Mass (FAB+)

m=z 347 (M^þþ1). Oxalate salt: mp 122–123 °C (dec);

Anal. [C₁₉H₂₆N₂O₄Æ(CO₂H)₂] C, H, N.

5.63. 3-[3-(2,4-Dichloro-phenyl)-isoxazol-5-yl]-2-diethyl-

aminomethyl-3-hydroxy-propionic acid ethyl ester

(4A6B2C7)

ND.

5.64. 2-(4-Methyl-piperazin-1-ylmethyl)-3-(3-phenyl-iso-

xazol-5-yl)-acrylic acid methyl ester [EþZ(15%)]

(5A1B1C1)

The product was obtained as pale yellow oil (58%); IR

(neat, cm^ꢂ1

5.60. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-diethyl-

aminomethyl-3-hydroxy-propionic acid ethyl ester

(4A3B2C7) (2:1)

)

1718 (CO₂Me); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:27 (s, 3H, NCH₃), 2.29 (s, 3H, NCH₃),

2.44 (br s, 8H, 4 ꢁ NCH₂), 2.58 (br s, 8H, 4 ꢁ NCH₂), 3.

36 (s, 2H, NCH₂), 3.63 (s, 2H, NCH₂), 3.86 (s, 6H,

2 ꢁ CO₂CH₃), 6.82 (s, 1H, @CH), 6.86 (s, 1H, @CH),

7.01 (s, 1H, @CH), 7.47–7.49 (m, 6H, Ar–H), 7.62 (s,

1H, @CH), 7.80–7.84 (m, 4H, Ar–H); Mass (FABþ)

m=z 342 (M^þþ1). Oxalate salt: mp 202–203 °C; Anal.

[C₁₉H₂₃N₃O₃Æ2(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (50%): IR

(neat, cm^ꢂ1) 1725 (CO₂Et), 3354 (OH); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 0:99–1:19 (m, 2t merged, 6H,

J ¼ 7:2 Hz, 2 ꢁ CH₃), 2.52–3.18 (m, 14H, 6 ꢁ NCH₂

and 2 ꢁ CH), 3.72–3.79 (m, 2q merged, 4H, J ¼ 7:0 Hz,

2 ꢁ OCH₂), 5.11 (s, 4H, 2 ꢁ OCH₂O), 5.28, 5.32 (d, 1H,

J ¼ 7:0 Hz, CH), 5.36, 5.39 (d, 1H, J ¼ 7:0 Hz, CH),

6.45 (s, 1H, @CH), 6.52 (s, 1H, @CH), 7.01, 7.05 (d, 4H,

J ¼ 8:4 Hz, Ar–H), 7.32–7.42 (m, 10H, Ar–H), 7.70–

7.74 (d, 4H, J ¼ 8:4 Hz, Ar–H); Mass (ESþ) m=z 452.73

(M^þþ1), 474.60 (M^þþNa). Oxalate salt: mp 150–152 °C

(dec); Anal. [C₂₆H₃₂N₂O₅Æ(CO₂H)₂] C, H, N.

5.65. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-

methyl-piperazin-1-ylmethyl)-acrylic acid methyl

ester (E) (5A3B1C1)

The product was obtained as pale yellow oil (55%); IR

(neat, cm^ꢂ1

)

1707 (CO₂Me); ¹H NMR (CDCl₃,

5.61. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-diethyl-

aminomethyl-3-hydroxy-propionic acid ethyl ester

(4A4B2C7) (2:1)

200 MHz) d 2.28 (s, 3H, NCH₃), 2.32–2.66 (m, 8H,

4 ꢁ NCH₂), 3.63 (s, 2H, NCH₂), 3.85 (s, 3H, CO₂CH₃),

5.13 (s, 2H, OCH₂O), 6.94 (s, 1H, @CH), 7.05, 7.09 (d,

2H, J ¼ 8:6 Hz, Ar–H), 7.36–7.43 (m, 5H, Ar–H), 7.60

(s, 1H, @CH), 7.73, 7.77 (d, 2H, J ¼ 8:6 Hz, Ar–H);

Mass (ESþ) m=z 447.93 (M^þþ1), 469.60 (M^þþNa).

The product was obtained as pale yellow oil (55%): IR

(neat, cm^ꢂ1) 1730 (CO₂Et), 3421 (OH); ¹H NMR

2072

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

Oxalate salt: mp 180–182 °C; Anal. [C₂₆H₂₉N₃O₄Æ2(CO₂-

H)₂] C, H, N.

4 ꢁ NCH₂), 2.58 (br s, 8H, 4 ꢁ NCH₂), 3.36 (s, 2H,

NCH₂), 3.58 (s, 2H, NCH₂), 4.25–4.35 (m, 2q merged,

4H, J ¼ 7:0 Hz, 2 ꢁ OCH₂), 6.74 (s, 1H, @CH), 6.95 (s,

1H, @CH), 7.29 (s, 1H, @CH), 7.34–7.52 (m, 6H, Ar–

H), 7.67 (s, 1H, @CH), 7.79–7.83 (m, 2H, Ar–H). Mass

(ESþ) m=z 390.20 (M^þþ1), 411.87 (M^þþNa). Oxalate

salt: mp 177–179 °C; Anal. [C₂₀H₂₄ClN₃O₃Æ2(CO₂H)₂]

C, H, N.

5.66. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-(4-methyl-

piperazin-1-ylmethyl)-acrylic acid methyl ester

(5A4B1C1) [EþZ(25%)]

The product was obtained as pale yellow oil (57%); IR

(neat, cm^ꢂ1

)

1720 (CO₂Me); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:26 (s, 3H, NCH₃), 2.30 (s, 3H, NCH₃),

2.43 (br s, 8H, 4 ꢁ NCH₂), 2.58 (br s, 8H, 4 ꢁ NCH₂),

3.36 (s, 2H, NCH₂), 3.59 (s, 2H, NCH₂), 3.86 (s, 6H,

2 ꢁ CO₂CH₃), 6.78 (s, 1H, @CH), 6.96 (s, 1H, @CH),

7.29 (s, 1H, @CH), 7.35–7.42 (m, 2H, Ar–H), 7.45–7.52

(m, 1H, Ar–H), 7.67 (s, 1H, @CH), 7.78–7.83 (m, 1H,

Ar–H); Mass (ESþ) m=z 375.80 (M^þþ1), 397.80

(M^þþNa). Oxalate salt: mp 188–190 °C; Anal.

[C₁₉H₂₂ClN₃O₃Æ2(CO₂H)₂] C, H, N.

5.70. 2-(4-Methyl-piperazin-1-ylmethyl)-3-(3-phenyl-

isoxazol-5-yl)-acrylic acid butyl ester (5A1B3C1)

[EþZ(15%)]

The product was obtained as pale yellow oil (61%); IR

(neat, cm^ꢂ1) 1715 (CO₂Bu-n); ¹H NMR (CDCl₃,

200 MHz) d ¼ 0:89–1:01 (m, 2t merged, 6H, J ¼ 7:2 Hz,

2 ꢁ CH₃), 1.40–1.55 (m, 4H, 2 ꢁ CH₂), 1.68–1.78 (m,

4H, 2 ꢁ CH₂), 2.27 (s, 3H, NCH₃), 2.29 (s, 3H, NCH₃),

2.44 (br s, 8H, 4 ꢁ NCH₂), 2.59 (br s, 8H, 4 ꢁ NCH₂),

3.35 (s, 2H, CH₂), 3.62 (s, 2H, CH₂), 4.22–4.31 (m, 2t

merged, 4H, J ¼ 6:4 Hz, OCH₂), 6.74 (s, 1H, @CH),

6.86 (s, 1H, @CH), 7.01 (s, 1H, @CH), 7.43–7.50 (m,

6H, Ar–H), 7.61 (s, 1H, @CH), 7.80-7.85 (m, 4H, A–

Hr); Mass (FABþ) m=z 384 (M^þþ1). Oxalate salt: mp

192–194 °C; Anal. [C₂₂H₂₉N₃O₃Æ2(CO₂H)₂] C, H, N.

5.67. 2-(4-Methyl-piperazin-1-ylmethyl)-3-(3-phenyl-

isoxazol-5-yl)-acrylic acid ethyl ester (5A1B2C1)

[EþZ(15%)]

The product was obtained as pale yellow oil (57%); IR

(neat, cm^ꢂ1) 1714 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:25 (t, 3H, J ¼ 7:2 Hz, CH₃), 1.36 (t, 3H,

J ¼ 7:2 Hz, CH₃), 2.33 (s, 3H, NCH₃), 2.35 (s, 3H,

NCH₃), 2.43–2.66 (m, 16H, 8 ꢁ NCH₂), 3.37 (s, 2H,

NCH₂), 3.66 (s, 2H, NCH₂), 4.12 (q, 2H, J ¼ 7:0 Hz,

OCH₂), 4.30 (q, 2H, J ¼ 7:0 Hz, OCH₂), 6.79 (s, 1H,

@CH), 6.86 (s, 1H, @CH), 6.97 (s, 1H, @CH), 7.43–7.50

(m, 6H, Ar–H), 7.60 (s, 1H, @CH), 7.78–7.84 (m, 4H,

Ar–H). Mass (FABþ) m=z 356 (M^þþ1). Oxalate salt:

mp 177–179 °C; Anal. [C₂₀H₂₅N₃O₃Æ2(CO₂H)₂] C, H,

N.

5.71. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-

methyl-piperazin-1-ylmethyl)-acrylic acid butyl ester

(5A3B3C1) [EþZ(15%)]

The product was obtained as pale yellow oil (62%); IR

(neat, cm^ꢂ1) 1715 (CO₂Bu-n); ¹H NMR (CDCl₃,

200 MHz) d ¼ 0:93 (t, 3H, J ¼ 7:2 Hz, 2 ꢁ CH₃), 1.40–

1.51 (m, 2H, 2 ꢁ CH₂), 1.64–1.74 (m, 2H, 2 ꢁ CH₂), 2.28

(s, 3H, NCH₃), 2.30 (s, 3H, NCH₃), 2.31–2.62 (m,

2 ꢁ 4H, NCH₂), 3.62 (s, 2H, CH₂), 3.85 (s, 2H, CH₂),

4.25 (t, 2 ꢁ 2H, OCH₂, J ¼ 6:5 Hz), 5.12 (s, 2H, OCH₂

O), 5.13 (s, 2H, CH₂Ph), 6.80 (s, 1H, CH), 6.93 (s, 1H,

@CH), 7.05, 7.09 (d, 2 ꢁ 2H, J ¼ 8:8 Hz, Ar–H), 7.34–

7.43 (m, 10H, Ar–H), 7.72, 7.76 (d, 2H, J ¼ 8:8 Hz, Ar–

H), 7.73, 7.77 (d, 2H, J ¼ 8:8 Hz, Ar–H). Mass (ESþ)

m=z 490.07 (M^þþ1), 511.93 (M^þþNa). Oxalate salt: mp

153–155 °C; Anal. [C₂₉H₃₅N₃O₄Æ2(CO₂H)₂] C, H, N.

5.68. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-

methyl-piperazin-1-ylmethyl)-acrylic acid ethyl ester

(5A3B2C1) (E)

The product was obtained as pale yellow oil (56%); IR

(neat, cm^ꢂ1) 1703 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:36 (t, 3H, J ¼ 7:1 Hz, CH₃), 2.28 (s, 3H, NCH₃),

2.40–2.60 (m, 8H, 4 ꢁ NCH₂), 3.63 (s, 2H, NCH₂), 4.30

(q, 2H, J ¼ 7:2 Hz, OCH₂), 5.13 (s, 2H, OCH₂O), 6.94

(s, 1H, @CH), 7.05, 7.09 (d, 2H, J ¼ 8:8 Hz, Ar–H),

7.33–7.45 (m, 5H, Ar–H), 7.60 (s, 1H, @CH), 7.73, 7.77

(d, 2H, J ¼ 8:8 Hz, Ar–H); Mass (ESþ) m=z 462.07

(M^þþ1), 484.20 (M^þþNa). Oxalate salt: mp 188–

190 °C; Anal. [C₂₇H₃₁N₃O₄Æ2(CO₂H)₂] C, H, N.

5.72. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-(4-methyl-

piperazin-1-ylmethyl)-acrylic acid butyl ester (5A4B3C1)

[EþZ(15%)]

The product was obtained as pale yellow oil (60%); IR

(neat, cm^ꢂ1) 1716 (CO₂Bu-n); ¹H NMR (CDCl₃,

200 MHz) d ¼ 0:98 (t, 6H, J ¼ 7.2 Hz, 2 ꢁ CH₃), 1.40–

1.47 (m, 4H, 2 ꢁ CH₂), 1.64–1.75 (m, 4H, 2 ꢁ CH₂), 2.26

(s,3H, NCH₃), 2.29 (s, 3H, NCH₃), 2.43 (br s, 8H,

2 ꢁ 4NCH₂), 2.57 (br s, 8H, 2 ꢁ NCH₂), 3.35 (s, 2H,

NCH₂), 3.58 (s, 2H, NCH₂), 4.26 (q, 4H, J ¼ 6:6 Hz,

2 ꢁ OCH₂), 6.73 (s, 1H, CH), 6.95 (s, 1H, @CH), 7.28 (s,

1H, @CH), 7.34–7.51(m, 6H, Ar–H), 7.65 (s, 1H, @CH),

7.79–7.83 (m, 2H, Ar–H). Mass (ESþ) m=z 439.87

(M^þþNa). Oxalate salt: mp 193–195 °C; Anal.

[C₂₂H₂₈ClN₃O₃Æ2(CO₂H)₂] C, H, N.

5.69. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-(4-methyl-

piperazin-1-ylmethyl)-acrylic acid ethyl ester (5A4B2C1)

[EþZ(20%)]

The product was obtained as pale yellow oil (61%); IR

(neat, cm^ꢂ1) 1718 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:25–1:39 (m, 2t merged, 6H, J ¼ 7:2 Hz, 2 ꢁ CH₃),

2.26 (s, 3H, NCH₃), 2.29 (s, 3H, NCH₃), 2.43 (br s, 8H,

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2073

5.73. 2-(4-Methyl-piperazin-1-ylmethyl)-3-(3-phenyl-

isoxazol-5-yl)-acrylonitrile (5A1B5C1) (Z)

(ESþ) m=z 472.87 (M^þþNa). Oxalate salt: mp 197–

198 °C; Anal. [C₂₆H₃₁N₃O₄Æ2(CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (59%); IR

(neat, cm^ꢂ1

)

2220 (CN); ¹H NMR (CDCl₃,

5.78. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-(4-methyl-

piperazin-1-ylmethyl)-propionic acid methyl ester

(7A4B1C1)

200 MHz) d ¼ 2:32 (s, 3H, NCH₃), 2.40–2.70 (m, 8H,

4 ꢁ NCH₂), 3.34 (s, 2H, NCH₂), 7.25 (s, 1H, @CH), 7.37

(s, 1H, @CH), 7.46–7.49 (m, 3H, Ar–H), 7.83–7.88 (m,

2H, Ar–H); Mass (FABþ) m=z 309 (M^þþ1). Oxalate

salt: mp 205–207 °C; Anal. [C₁₈H₂₀N₄OÆ2(CO₂H)₂] C, H,

N.

The product was obtained as pale yellow oil (72%); IR

(neat, cm^ꢂ1

)

1736 (CO₂Me); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:29 (s, 3H, NCH₃), 2.46–2.70 (m, 10H,

5 ꢁ NCH₂), 3.13 (br s, 3H, CH and CH₂), 3.69 (s, 3H,

OCH₃), 6.49 (s, 1H, @CH), 7.34–7.41 (m, 2H, Ar–H),

7.46–7.50 (m, 1H, Ar–H), 7.69–7.74 (m, 1H, Ar–H);

Mass (ESþ) m=z 379.20 (M^þþ1), 401.00 (M^þþNa).

Oxalate salt: mp 190–191 °C; Anal. [C₁₉H₃₀ClN₃-

O₃Æ2(CO₂H)₂] C, H, N.

5.74. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-

methyl-piperazin-1-ylmethyl)-acrylonitrile (5A3B5C1)

(Z)

The product was obtained as pale yellow oil (59%); IR

1

(neat, cm^ꢂ1) 2218 (CN); H NMR (CDCl₃, 200 MHz)

d ¼ 2:31 (s, 3H, NCH₃), 2.42–2.64 (m, 8H, 4 ꢁ NCH₂),

3.32 (s, 2H, CH₂), 5.13 (s, 2H, OCH₂O), 7.04, 7.08 (d,

2H, J ¼ 8:8 Hz, Ar–H), 7.22–7.43 (m, 6H, 5Ar–H and

@CH), 7.77, 7.81 (d, 2H, J ¼ 8:8 Hz, Ar); Mass (ESþ)

m=z 436.60 (M^þþNa). Oxalate salt: mp 207–208 °C;

Anal. [C₂₅H₂₆N₄O₂Æ2(CO₂H)₂] C, H, N.

5.79. 2-(4-Methyl-piperazin-1-ylmethyl)-3-(3-phenyl-iso-

xazol-5-yl)-propionic acid ethyl ester (7A1B2C1)

The product was obtained as colourless oil (63%);

IR (neat, cm^ꢂ1) 1731 (CO₂Et); ¹H NMR (CDCl₃,

200 MHz) d ¼ 1:23 (t, 3H, J ¼ 7:2 Hz, CH₃), 2.27 (s,

3H, NCH₃), 2.32–2.75 (m, 10H, 5 ꢁ N CH₂), 3.07 (br s,

3H, CH and CH₂), 4.14 (q, 2H, J ¼ 7:1 Hz, OCH₂), 6.33

(s, 1H, @CH), 7.42–7.45 (m, 3H, Ar–H), 7.75–7.80 (m,

2H, Ar–H); Mass (FABþ) m=z 358 (M^þþ1). Oxalate

salt: mp 201–202 °C; Anal. [C₂₀H₂₇N₃O₃Æ2(CO₂H)₂] C,

H, N.

5.75. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-(4-methyl-

piperazin-1-ylmethyl) acrylonitrile (5A4B5C1) (Z)

The product was obtained as pale yellow oil (61%); IR

1

(neat, cm^ꢂ1) 2218 (CN); H NMR (CDCl₃, 200 MHz)

d ¼ 2:23 (s, 3H, NCH₃), 2.40–2.61 (m, 8H,, NCH₃), 3.34

(s, 2H, NCH₂), 7.36–7.54 (m, 4H, 2Ar–H merged with

2 ꢁ @CH), 7.71–7.76 (m, 2H, Ar–H). Mass (ESþ) m=z

447.93 (M^þþ1), 469.60 (M^þþNa). Oxalate salt: mp 190–

192 °C; Anal. [C₁₈H₁₉ClN₄OÆ2(CO₂H)₂] C, H, N.

5.80. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-

methyl-piperazin-1-ylmethyl)-propionic acid ethyl

ester (7A3B2C1)

The product was obtained as pale yellow oil (68%); IR

(neat, cm^ꢂ1) 1732 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:23 (t, 3H, J ¼ 7:2 Hz, CH₃), 2.29 (s, 3H, NCH₃),

2.30–2.78 (m, 10H, 5 ꢁ N CH₂and CH), 3.07 (br s, 3H,

CH and CH₂), 4.14 (q, 2H, J ¼ 7:1 Hz, OCH₂), 5.11 (s,

2H, OCH₂O), 6.27 (s, 1H, @CH), 7.01, 7.05 (d, 2H,

J ¼ 8:8 Hz, Ar–H), 7.32–7.65 (m, 5H, Ar), 7.68, 7.72 (d,

2H, J ¼ 8:8 Hz, Ar–H); Mass (ESþ) m=z 464.13

(M^þþ1), 485.8 (M^þþNa). Oxalate salt: mp 203–204 °C;

Anal. [C₂₇H₃₃N₃O₄Æ2(CO₂H)₂] C, H, N.

5.76. 2-(4-Methyl-piperazin-1-ylmethyl)-3-(3-phenyl-iso-

xazol-5-yl)-propionic acid methyl ester (7A1B1C1)

The product was obtained as pale yellow oil (71%); IR

(neat, cm^ꢂ1

)

1734 (CO₂Me); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:28 (s, 3H, NCH₃), 2.43–2.68 (m, 10H,

5 ꢁ NCH₂), 3.08 (br s, 3H, CH and CH₂), 3.68 (s, 3H,

CO₂CH₃), 6.33 (s, 1H, @CH), 7.42–7.45 (m, 3H, Ar–H),

7.75–7.80 (m, 2H, Ar); Mass (FABþ) m=z 344 (M^þþ1).

Oxalate salt: mp194–195 °C; Anal. [C₁₉H₂₅N₃-

O₃Æ2(CO₂H)₂] C, H, N.

5.81. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-(4-methyl-

piperazin-1-ylmethyl)-propionic acid ethyl ester

(7A4B2C1)

5.77. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-

methyl-piperazin-1-ylmethyl)-propionic acid methyl

ester (7A3B1C1)

The product was obtained as yellow oil (65%); IR (neat,

cm^ꢂ1) 1732 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:24 (t, 3H, J ¼ 7:2 Hz, CH₃), 2.27 (s, 3H, NCH₃),

2.42–2.57 (m, 10H, 5 ꢁ NCH₂), 3.16 (m, 3H, CH₂), 4.15

(q, 2H, J ¼ 7:1 Hz, OCH₂), 6.49 (s, 1H, @CH), 7.34–

7.38 (m, 2H, Ar–H), 7.46–7.50 (m, 1H, Ar–H,), 7.69–

7.74 (m, 1H, Ar–H); Mass (FABþ) m=z 392 (M^þþ1).

Oxalate salt: mp 202–203 °C; Anal. [C₂₀H₂₆ClN₃-

O₃Æ2 (CO₂H)₂] C, H, N.

The product was obtained as pale yellow oil (68%); IR

(neat, cm^ꢂ1

)

1732 (CO₂Me); ¹H NMR (CDCl₃,

200 MHz) d ¼ 2:28 (s, 3H, NCH₃), 2.36–2.66 (m, 10H,

5 ꢁ NCH₂), 3.09 (br s, 3H, CH and CH₂), 3.68 (s, 3H,

CO₂CH₃), 5.11 (s, 2H, OCH₂O), 6.26 (s, 1H, @CH),

7.01, 7.05 (d, 2H, J ¼ 8:8 Hz, Ar–H), 7.32–7.51 (m, 5H,

Ar–H), 7.69, 7.73 (d, 2H, J ¼ 8:7 Hz, Ar–H); Mass

2074

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

5.82. 2-(4-Methyl-piperazin-1-ylmethyl)-3-(3-phenyl-iso-

xazol-5-yl)-propionic acid butyl ester (7A1B3C1)

5.86. DABCO-mediated reaction of NaBH₄with acetate

of Baylis–Hillman adducts––general procedure

The product was obtained as light brown oil (67%); IR

(neat, cm^ꢂ1) 1728 (CO₂Bu-n); ¹H NMR (CDCl₃,

200 MHz) d ¼ 0:88 (t, 3H, J ¼ 7:2 Hz, CH₃), 1.28–1.39

(m, 4H, CH₂), 1.51–1.61 (m, 2H, CH₂), 2.27 (s, 3H,

NCH₃), 2.43–2.69 (m, 10H, 5 ꢁ NCH₂), 3.07–3.16 (m,

3H, CH and CH₂), 4.09 (t, 2H, J ¼ 6:5 Hz, OCH₂), 6.33

(s, 1H, @CH), 7.42–7.45 (m, 3H, Ar–H), 7.75–7.79 (m,

2H, Ar–H); Mass (FABþ) m=z 386 (M^þþ1). Oxalate

salt: mp 190–191 °C; Anal. [C₂₂H₃₁N₃O₃Æ2(CO₂H)₂] C,

H, N.

To the solution of appropriate acetate 3 (2 mmol) in

THF/water (3 mL, 1:1, v/v) was added DABCO (0.22 g,

2 mmol) and the reaction was allowed to proceed at rt.

As soon as the solution becomes clear (ca 15 min),

NaBH₄(0.08 g, 2 mmol) was added with stirring. The

reaction was complete in 15 min, after which the reac-

tion mixture was extracted with ethyl acetate

(2 ꢁ 30 mL). The organic layers were combined, dried

over anhyd Na₂SO₄and evaporated to obtain com-

pounds 6 in suﬃciently pure form. In few cases the

analytical sample was prepared by column chromato-

graphy over silica gel using hexane/ethyl acetate (85:15,

v/v) as eluent.

5.83. 3-[3-(4-Benzyloxy-phenyl)-isoxazol-5-yl]-2-(4-

methyl-piperazin-1-ylmethyl)-propionic acid butyl

ester (7A3B3C1)

5.87. 2-(3-Phenyl-isoxazol-5-ylmethyl)-acrylic acid

methyl ester (6A1B1)

The product was obtained as light brown oil (67%); IR

(neat, cm^ꢂ1) 1731 (CO₂Bu-n); ¹H NMR (CDCl₃,

200 MHz) d ¼ 0:88 (t, 3H, J ¼ 7:2 Hz, CH₃), 1.25–1.39

(m, 2H, CH₂), 1.50–1.66 (m, 2H, CH₂), 2.28 (s, 3H,

NCH₃), 2.31–2.69 (m, 10H, 5 ꢁ NCH₂), 3.07 (br s, 3H,

CH and CH₂), 4.09 (t, 2H, J ¼ 6:4 Hz, OCH₂), 5.11 (s,

2H, OCH₂O), 6.26 (s,1H, @CH) 7.01, 7.05 (d, 2H, Ar,

J ¼ 8:8 Hz), 7.33–7.42 (m, 5H, Ar–H), 7.68, 7.72 (d, 2H,

J ¼ 8:8 Hz, Ar–H); Mass (FABþ) m=z 492 (M^þþ1).

Oxalate salt: mp 193–194 °C; Anal. [C₂₉H₃₇N₃-

O₄Æ2(CO₂H)₂] C, H, N.

The product was obtained as colourless oil (81%); IR

(neat, cm^ꢂ1

)

1721 (CO₂Me); ¹H NMR (CDCl₃,

200 MHz) d ¼ 3:79 (s, 3H, CO₂CH₃), 3.84 (s, 2H, CH₂),

5.77 (s, 1H, @CH₂), 6.36 (s, 1H, @CH₂), 6.39 (s,

1H, @CH), 7.42–7.45 (m, 3H, Ar–H), 7.76–7.81 (m, 3H,

Ar–H); Mass (FABþ) m=z 244 (M^þþ1); Anal.

[C₁₄H₁₃NO₃] C, H, N.

5.88. 2-[3-(4-Benzyloxy-phenyl)-isoxazol-5-ylmethyl]-

acrylic acid methyl ester (6A3B1)

5.84. 3-[3-(2-Chloro-phenyl)-isoxazol-5-yl]-2-(4-methyl-

piperazin-1-ylmethyl)-propionic acid butyl ester

(7A4B3C1)

The product was obtained as a white solid (89%); mp

90–92 °C; IR (KBr, cm^ꢂ1) 1718 (CO₂Me); ¹H NMR

(CDCl₃, 200 MHz) d ¼ 3:78 (s, 3H, CO₂CH₃), 3.82 (s,

2H, CH₂), 5.11 (s, 2H, OCH₂O), 5.76 (s, 1H, @CH₂),

6.30 (s, 1H, @CH₂), 6.38 (s, 1H, @CH), 7.01, 7.05 (d,

2H, J ¼ 8:8 Hz, Ar–H), 7.33–7.42 (m, 5H, Ar–H), 7.70,

7.74 (d, 2H, J ¼ 8:8 Hz Ar–H); Mass (FABþ) m=z 350

(M^þþ1); Anal. [C₂₁H₁₉NO₄] C, H, N.

The product was obtained as brown oil (69%); IR (neat,

1

cm^ꢂ1) 1733 (CO₂Bu-n); H NMR (CDCl₃, 200 MHz)

d ¼ 0:89 (m, 3H, CH₃), 1.25–1.40 (m, 4H, CH₂), 2.28 (s,

3H, NCH₃), 2.43–2.70 (m, 10H, 5 ꢁ NCH₂), 3.09 (br s,

3H, CH and CH₂), 4.09 (t, 2H, J ¼ 6:6 Hz, OCH₂), 6.49

(s, 1H, @CH), 7.33–7.41 (m, 2H, Ar–H), 7.46–7.50 (m,

1H, Ar–H), 7.69-7.74 (m, 1H, Ar–H); Mass (FABþ) m=z

420 (M^þþ1). Oxalate salt: mp 195–196 °C; Anal.

[C₂₂H₃₀ClN₃O₃Æ2(CO₂H)₂] C, H, N.

5.89. 2-[3-(2-Chloro-phenyl)-isoxazol-5-ylmethyl]-acrylic

acid methyl ester (6A4B1)

The product was obtained as colourless oil (99%); IR

(neat, cm^ꢂ1

)

1722 (CO₂Me); ¹H NMR (CDCl₃,

5.85. Acetylation––general procedure

200 MHz) d ¼ 3:79 (s, 3H, CO₂CH₃), 3.86 (s, 2H, CH₂),

5.77 (s, 1H, @CH₂), 6.39 (s, 1H @CH₂), 6.52 (s, 1H,

@CH), 7.34–7.38 (m, 2H, Ar–H), 7.46–7.51 (m, 1H, Ar–

H), 7.70–7.74 (m, 1H, Ar–H); Mass (FAB+) m=z 278

(M^þþ1); Anal. [C₁₄H₁₂ClNO₃] C, H, N.

To a stirred solution of appropriate compound from 2

(3.25 mmol) in dry dichloromethane (5 mL) was added

pyridine (0.48 mL, 6.0 mmol) followed by a dropwise

addition of solution of acetyl chloride (0.46 mL,

6.5 mmol) in dry dichloromethane (3 mL) at 0 °C. After

the addition was complete, the reaction was continued

at rt for 1 h. The reaction mixture was extracted with

dichloromethane (2 ꢁ 30 mL) and water (50 mL). The

organic layers were combined, washed with brine, dried

over anhyd Na₂SO₄and evaporated to obtain an oily

residue. The residue was puriﬁed on a small band of

silica gel using hexane/ethyl acetate (85:15, v/v) as eluent

to obtain pure acetates 3.

5.90. 2-(3-Phenyl-isoxazol-5-ylmethyl)-acrylic acid ethyl

ester (6A1B2)

The product was obtained as colourless oil (82%); IR

(neat, cm^ꢂ1) 1716 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:30 (t, 3H, J ¼ 7.2 Hz, CH₃), 3.83 (s, 2H, CH₂),

4.23 (q, 2H, J ¼ 7:2 Hz, OCH₂); 5.75 (s, 1H, @CH₂),

6.36 (s, 1H, @CH₂), 6.38 (s, 1H, @CH), 7.42–7.45 (m,

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2075

3H, Ar–H), 7.76–7.80 (m, 2H, Ar–H); Mass (ESþ) m=z

258.27 (M^þþ1), 280.40 (M^þþNa); Anal. [C₁₅H₁₅NO₃]

C, H, N.

(m, 2H, CH₂), 1.57–1.72 (m, 2H, CH₂), 3.86 (s, 2H,

CH₂), 4.18 (t, 2H, J ¼ 6:5 Hz, OCH₂), 5.75 (s, 1H,

@CH₂), 6.39 (s, 1H, @CH₂), 6.52 (s, 1H, @CH), 7.30–

7.42 (m, 2H, Ar–H), 7.46–7.50 (m, 1H, Ar–H), 7.70–7.75

(m, 1H, Ar–H); Mass (FABþ) m=z 320 (M^þþ1); Anal.

[C₁₇H₁₈ClNO₃] C, H, N.

5.91. 2-[3-(4-Benzyloxy-phenyl)-isoxazol-5-ylmethyl]-

acrylic acid ethyl ester (6A3B2)

The product was obtained as colourless oil (99%); IR

(neat, cm^ꢂ1) 1705 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:29 (t, 3H, J ¼ 7:2 Hz, CH₃), 4.22 (q, 2H,

J ¼ 7:1 Hz, OCH₂), 5.11 (s, 2H, OCH₂O), 5.74 (s, 1H,

@CH₂), 6.30 (s, 1H, @CH), 6.37 (s, 1H, @CH), 7.01,

7.05 (d, 2H, J ¼ 8:8 Hz, Ar–H), 7.30-7.52 (m, 5H, Ar–

H), 7.70, 7.74 (d, 2H, J ¼ 8:8 Hz Ar–H); Mass (ESþ)

m=z 386.33 (M^þþNa); Anal. [C₂₂H₂₁NO₄] C, H, N.

6. Biological assays

6.1. Animals

Experiments on pulmonary thromboembolism and

bleeding time were performed on male Swiss mice

(average wt 23 g). New Zealand white strain rabbits of

either sex were also used to evaluate antithrombotic

eﬀect of the test compound. While, male Sprague

Dawley rats (250–300 g) were used for the aggregation

experiments. All the animals were kept in polypropylene

cages and maintained at 24 ꢀ 0.5 °C, 12 h day/night cycle

in the Animal House of the Central Drug Research

Institute, and were provided with chow pellets and water

ad libitum. All the experiments were performed in

accordance with the ethical and animal care guidelines

of the Institute.

5.92. 2-[3-(2-Chloro-phenyl)-isoxazol-5-ylmethyl]-acrylic

acid ethyl ester (6A4B2)

The product was obtained as colourless oil (88%); IR

(neat, cm^ꢂ1) 1718 (CO₂Et); ¹H NMR (CDCl₃, 200 MHz)

d ¼ 1:29 (t, 3H, J ¼ 7:2 Hz, CH₃), 3.86 (s, 2H, CH₂),

4.23(q, 2H, J ¼ 7:2 Hz, OCH₂), 5.75 (s, 1H @CH₂), 6.39

(s, 1H, @CH₂), 6.52 (s, 1H, @CH), 7.33–7.41 (m, 2H,

Ar–H), 7.45–7.50 (m, 1H, Ar–H), 7.70–7.75 (m, 1H, Ar–

H); Mass (ESþ) m=z 314.00 (M^þþNa); Anal.

[C₁₅H₁₄ClNO₃] C, H, N.

6.2. Chemicals

Adenosine 5⁰-diphosphate (ADP), arachidonic acid

(AA), calcium ionophore (A23187), collagen, phorbol

myristate acetate (PMA) and thrombin were dissolved in

either saline or DMSO and stored at )20 °C. Fresh

dilutions were prepared at the time of experiment. All

the reagents were obtained from Sigma Chemical Co.

(St. Louis, USA).

5.93. 2-(3-Phenyl-isoxazol-5-ylmethyl)-acrylic acid

butyl ester (6A1B3)

The product was obtained as colourless oil (89%); IR

(neat, cm^ꢂ1) 1715 (CO₂Bu-n); ¹H NMR (CDCl₃,

200 MHz) d ¼ 0:92 (t, 3H, J ¼ 7:2 Hz, CH₃), 1.29–1.47

(m, 2H, CH₂), 1.59–1.72 (m, 2H, CH₂), 3.84 (s, 2H, CH),

4.18 (t, 2H, J ¼ 6:5 Hz, OCH₂), 5.75 (s, 1H, @CH₂), 6.36

(s, 1H, @CH₂), 6.38 (s, 1H, @CH), 7.42–7.47 (m, 3H, Ar–

H), 7.76–7.81 (m, 2H, Ar–H); Mass (ESþ) m=z 286.60

(M^þþ1), 308.40 (M^þNa); Anal. [C₁₇H₁₉NO₃] C, H, N.

6.3. Thrombin assay

The compound and its analogues (100 lg/mL) were

assayed for their thrombin inhibitory activity (in vitro)

by the amidolytic assay.²²Enzyme inhibition in presence

of compound was measured in a total volume of 250 L

containing Tris buﬀer 100 M (0.75 M NaCl, 10 mM

CaCl₂, 0.1% BSA, pH 7.5), thrombin substrate (0.2 mM)

and thrombin (3 nM). Stock solutions of the compounds

were prepared in triple distilled water and diluted in the

assay buﬀer prior to the experiment.

5.94. 2-[3-(4-Benzyloxy-phenyl)-isoxazol-5-ylmethyl]-

acrylic acid butyl ester (6A3B3)

The product was obtained as a white solid (69%); mp

1

66–68 °C; IR (KBr, cm^ꢂ1) 1716 (CO₂Bu-n); H NMR

(CDCl₃, 200 MHz) d ¼ 0:92 (t, 3H, J ¼ 7:2 Hz, CH₃),

1.26–1.47 (m, 2H, CH₂), 1.57–1.72 (m, 2H, CH₂), 3.81

(s, 2H, CH₂), 4.17 (t, 2H, J ¼ 6:4 Hz, OCH₂), 5.11 (s,

2H, OCH₂O), 5.74 (s, 1H, @CH₂), 6.29 (s, 1H, @CH₂),

6.37 (s, 1H, @CH), 7.01, 7.05 (d, 2H, J ¼ 8:8 Hz, Ar–H),

7.33–7.46 (m, 5H, Ar–H), 7.70, 7.74 (d, 2H, J ¼ 8:8 Hz

Ar–H); Mass (FABþ) m=z 392 (M^þþ1); Anal.

[C₂₄H₂₅NO₄] C, H, N.

6.4. Evaluation of coagulation parameters

Blood was collected by cardiac puncture of the ether-

anaesthetized rat into a syringe containing 3.8% tri-

sodium citrate (9:1, v/v). It was centrifuged at 2500 g for

15 min at 20 °C. Test compounds were prepared in

physiological saline (0.9% NaCl). Coagulation parame-

ters, that is, thrombin time (TT), prothrombin time (PT)

and activated partial thromboplastin time (APTT) were

evaluated according to the manufacturerꢀs instructions

and measured in a coagulometer (Stago, France).

5.95. 2-[3-(2-Chloro-phenyl)-isoxazol-5-ylmethyl]-acrylic

acid butyl ester (6A4B3)

The product was obtained as colourless oil (90%); IR

(neat, cm^ꢂ1) 1719 (CO₂Bu-n); ¹H NMR (CDCl₃,

200 MHz) d ¼ 0:93 (t, 3H, J ¼ 7:2 Hz, CH₃), 1.26–1.47

2076

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

6.5. Evaluation of compounds on platelet aggregation

were removed and opened longitudinally and the

thrombus was carefully removed and weighed. Heparin

sodium (Beparine from beef intestinal mucosa P140

USP units/mg; Biological E. Limited, India) was given in

the doses of (0.5, 0.25, 0.1 mg/kg iv, via ear vein; n ¼ 6

observations for each dose in nine animals) 5 min before

stasis and test compound (99/353; n ¼ 12 observations

in 3 animals at 30 lM kg^ꢂ1, po) or its saline vehicle

(n ¼ 10 observations in ﬁve animals) were administered

per orally 2 h prior to stasis.

Sprague Dawley rats (wt 250–300 gm) were anaesthe-

tized with ether and blood (9 mL) was drawn from the

heart into a plastic syringe containing 1 mL of 1.9% tri-

sodium citrate. It was centrifuged at 275 ꢁ g for 20 min,

at 20 °C and the platelet rich plasma (PRP) was sepa-

rated. The remaining blood was further centrifuged at

1500 ꢁ g for 15 min at 20 °C to obtain platelet poor

plasma (PPP). The platelet count in the PRP was

adjusted to 2 ꢁ 10⁸cells/mL by using PPP. Aggregation

was induced by adenosine-5⁰-diphosphate (ADP),

thrombin, collagen, or calcium ionophore A23187 and

was monitored on a dual channel aggregometer (Chro-

nolog, USA).¹⁶The test compound was incubated with

PRP for 5 min before the addition of aggregation

inducing agent. Percent inhibition of the test compounds

at various concentrations was calculated as follows:

Acknowledgements

The ﬁnancial support in the form of fellowships to four

of the authors AP, PS, SAVR and WRS from CSIR and

AKR from ICMR, India is gratefully acknowledged.

This work was supported partially through ﬁnancial

grant under DST Project no SR/SI/OC-04/2003. The

technical assistance by Mrs. K. Bhutani and Mr. M. S.

Ansari towards biological evaluation of compounds is

also gratefully acknowledged.

%Inhibition ¼ ½1 ꢂ Aggregation_test=Aggregation_vehicle

ꢁ 100

ꢃ

IC₅₀for the test compounds was determined by a non-

linear plot between % inhibition and concentration of

the test substance.

References and notes

1. Thrombosis in Cardiovascular Disorders; Fuster, V., Ver-

straete, M., Eds.; W.B. Saunders: Philadelphia, 1992.

2. (a) Gresele, P.; Agnelli, G. TIPS 2002, 23, 25–32; (b)

Collins, B.; Hollidge, C. Nature Rev. Drug Discovery 2003,

2, 11–12.

6.6. Eﬀect on mouse thrombosis

Pulmonary thromboembolism was induced by a method

described earlier.¹⁶The compounds to be tested or the

vehicle were administered orally 60 min prior to the

thrombotic challenge. Thrombosis was induced by a

mixture of collagen (150 lg/mL) and adrenaline (50 lg/

mL) by the rapid intravenous injection into the tail vein

to induce hind limb paralysis or death. In each group 10

animals were used for evaluating the test compound,

aspirin or vehicle.

3. Raghavan, S. A. V.; Dikshit, M. Drugs Future 2002, 27,

669–683, and references cited therein.

4. Gachet, C.; Cattaneo, M.; Ohlmann, P.; Hechler, B.;

Lecchi, A.; Chevalier, J.; Cassel, D.; Mannucci, P. M.;

Cazenave, J. P. Br. J. Haematol 1995, 91, 434–444.

5. Gachet, C.; Hechler, B.; Leon, C.; Vial, C.; Leray, C.;

Ohlmann, P.; Cazenave, J. P. Thromb. Haemost. 1997, 78,

306–309.

6. Tandon, N. N.; Kralisz, U.; Jamieson, G. A. J. Biol.

Chem. 1989, 264, 7576–7583.

7. Kainoh, M.; Ikeda, Y.; Nishio, S.; Nakadate, T. Thromb.

Res. 1992, 65, 165–176.

Protection against collagen plus epinephrine was ex-

pressed as

8. (a) Hanessian, S.; Therrien, E.; Granberg, K.; Nilsson, I.

Bioorg. Med. Chem. Lett. 2002, 12, 2907–2911; (b)

Sielecki, T. M.; Liu, J.; Mousa, S. A.; Racanelli, A. L.;

Hausner, E. A.; Wexler, R. R.; Olson, R. E. Bioorg. Med.

Chem. Lett. 2001, 11, 2201–2204; (c) Ballabeni, V.;

Tognolini, M.; Calcina, F.; Impicciatore, M.; Vicini, P.;

Barocelli, E. Pharmacol. Res. 2002, 46, 389–393.

9. (a) Pruitt, J. R.; Pinto, D. J.; Estrella, M. J.; Bostrom, L.

L.; Knabb, R. M.; Wong, P. C.; Wright, M. R.; Wexler, R.

R. Bioorg. Med. Chem. Lett. 2000, 10, 685–689; (b)

Nantermet, P. G.; Barow, J. C.; Lundell, G. F.; Pellicore,

J. M.; Rittle, K. E.; Young, M. B.; Friedanger, R. M.;

Connoly, T. M.; Condra, C.; Karczewski, J.; Bednar, R.

M.; Gaul, S. L.; Gould, R. J.; Prendergast, K.; Selnick, H.

G. Bioorg. Med. Chem. Lett. 2002, 12, 319–323.

10. Batra, S.; Srinivasan, T.; Rastogi, S. K.; Kundu, B.; Patra,

A.; Bhaduri, A. P.; Dikshit, M. Bioorg. Med. Chem. Lett.

2002, 12, 1905–1908.

ð1 ꢂ P_test=P_controlÞ ꢁ 100

where P_testis the number of animals paralyzed/dead in

test compound-treated group, and P_controlis the number

of animals paralyzed/dead in vehicle treated group.

6.7. Rabbit venous thrombosis model

Experiments were performed on New Zealand white

strain rabbits (2–3 kg) either sex. Escherichia coli LPS

strain 1055:B5 (Sigma Chemicals, USA) was injected

intravenously via ear vein (1 lg/kg).^13;14Jugular veins on

the both sides were exposed and dissected free from

surrounding tissue. Two loose sutures were placed

1.5 cm apart and all collateral veins were ligated. Four

hours after E. coli endotoxin injection (animal is wat-

ched for any signs of hypersensitivity reaction during

this period), stasis was established and maintained for

45 min by tightening the two sutures. Ligated segments

11. Original papers on Baylis–Hillman reaction (a) Morita,

K.; Suzuki, Z.; Hirose, H. Bull. Chem. Soc. Jpn. 1968, 41,

2815; (b) Baylis, A.B.; Hillman, M.E.D. German Patent

2155113, 1972; Chem Abstr. 1972, 77, 34174q; (c) Reviews

S. Batra et al. / Bioorg. Med. Chem. 12 (2004) 2059–2077

2077

Drewes, S. E.; Roos, G. H. P. Tetrahedron 1988, 44, 4653–

4670; (d) Basavaiah, D.; Rao, P. D.; Hyma, R. S.

Tetrahedron 1996, 52, 8001–8062; (e) Ciganek, E. Org.

React. 1997, 51, 201–350; (f) Kim, J. N.; Lee, K. Y. Curr.

Org. Chem. 2002, 6, 627–645; (g) Basavaiah, D.; Rao, A.

J.; Satyanarayana, T. Chem. Rev. 2003, 103, 811–890.

12. Diminno, G.; Silver, M. J. J. Pharmacol. Exp. Ther. 1983,

225, 57–60.

16. Dikshit, M.; Kumari, R.; Srimal, R. C. J. Pharmacol. Exp.

Ther. 1993, 265, 1369–1373.

17. Tolentino, A. R.; Bahou, W. F. In Platelets; Michelson, A.

D., Ed.; Academic, 2002; pp 117–129.

18. Heyu, N.; Freedman, J. Science 2003, 28, 264–275.

19. Hato, T.; Ginsberg, M. H.; Shattil, S. J. In Platelets;

Michelson, A. D., Ed.; Academic, 2002; pp 105–110.

20. Siess, W.; Lapetina, E. G. Biochem. J. 1988, 255, 309–

318.

13. Berry, C. N.; Girard, D.; Girardot, C.; Lochot, S.;

Lunven, C.; Visconte, C. Semin. Thromb. Haemost. 1996,

22, 233–241.

21. Vuori, K.; Ruoslahti, E. J. Biol. Chem. 1993, 268, 21459–

21462.

14. Herbert, J. M.; Bernat, A.; Dol, F.; Herault, J. P.; Crepon,

B.; Lormeau, J. M. J. Pharmacol. Exp. Ther. 1996, 276,

1030–1038.

15. Dejna, E.; Collioni, A.; Quntana, A. Thromb. Res. 1979,

15, 191–197.

22. Moon, J. C.; Junling, L.; Tamara, I. P.; Shirley, S.;

Dennis, W. T.; Thomas, M. C.; Demin, W.; Carl, W. J.;

Gartner, T. K. Blood 2003, 101, 2646–2651.

23. Patra, A.; Batra, S.; Kundu, B.; Joshi, B. S.; Roy, R.;

Bhaduri, A. P. Synthesis 2001, 276–280.

Article Doi

Baylis-Hillman reaction assisted parallel synthesis of 3,5-disubstituted isoxazoles and their in vivo bioevaluation as antithrombotic agents

DOI: 10.1016/j.bmc.2004.02.023

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Full text of DOI:10.1016/j.bmc.2004.02.023

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