1 recyclable organomolybdenum lewis acid catalyst and microwave assisted pechmann condensation...

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Recyclable Organomolybdenum LewiRecyclable Organomolybdenum Lewis Acid Catalyst and Microwave Assistes Acid Catalyst and Microwave Assisted Pechmann Condensation Reactionsd Pechmann Condensation Reactions

Student : Chia-Pei Chung Supervisor : Prof. Shuchun Joyce Yu

2006 / 07 / 20Department of Chemistry & Biochemistry

Chung Cheng University

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Pechmann CondensationPechmann CondensationPechmann CondensationPechmann Condensation

The Pechmann condensation is a synthesis of coumarins, starting from a phenol and a ester or carboxylic acid containing a β-carbonyl group.

Coumarin synthesis

Woodruff, E. H. Organic Syntheses, 1944, 24, 69.Pechmann, H. V.; Duisberg, C. Ber. 1883, 16, 2119.

OH

OEt

OO O O

+2 eq. AlCl3, PhNO2

100 ~ 130 oC4 h

Phenol Ethyl acetoacetate 80%

3

CoumarinsCoumarinsCoumarinsCoumarins

present in seeds, root, and leaves of many plant species

As additives to food and cosmetics, optical brightening agents, and dispersed fluorescent and laser dyes

has clinical value as the precursor for several anticoagulants, antibacterial, anticancer

can be synthesized by one of such methods as the Claisen rearrangement, Perkin reaction, Knoevenagel condensation, Reformatsky reaction, Wittig reactions, as well as the Pechmann Condensation reaction

1

2

345

6

7

88a O

4a

O

benzo-2-pyrone

4

Acidic Catalysts for Pechmann CondensationAcidic Catalysts for Pechmann Condensation

Proton Donor Brønsted AcidsProton Donor Brønsted Acids

H2SO4, HCl, TFA (trifluoroacetic acid)

Pechmann V. H.; Duisberg C. Chem. Ber. 1884, 17, 929.

Woods, L. L.; Sapp, J. J. Org. Chem. 1962, 27, 3703.

Traditional Lewis Acid CatalystsTraditional Lewis Acid Catalysts

InCl3, AlCl3, BiCl3, FeCl3, TiCl4, ZrCl4, P2O5, PCl3, POCl3

Bose, D. S.; Rudradas, A. P.; Babu, M. H. Tetrahedron Lett. 2002, 43, 9195.

S. K. De, R. A. Gibbs, Synthesis, 2005, 1231.

Simmonis, H.; Remmert, P. Chem. Ber. 1914, 47, 2229.

Robertson, A.; Sandrock, W. F.; Henry, C. B. J. Chem. Soc. 1931, 2426.

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Acidic Catalysts for Acidic Catalysts for Pechmann Condensation -- continued Pechmann Condensation -- continued

Lanthanide Lewis Acid CatalystsLanthanide Lewis Acid Catalysts

Yb(III), Sm(III) Fillion, E. et. al. J. Org. Chem. 2006, 71, 409.

Bahekar, S. S.; Shinde, D. B. Tetrahedron Lett. 2004, 45, 7999.

OthersOthers

graphite / montmorillonite K10

Amberlyst-15, Nafion

Heteropoly acid (H6P2W18O62 ． 24H2O)

Fre`re, S.; Thie´ry, V.; Besson, T. Tetrahedron Lett. 2001, 42, 2791.

Sabou, R.; Hoelderich, W. F.; Ramprasad, D.; Weinand, R. J. Catal. 2005, 232, 34.

Laufer, M. C.; Hausmann, H.; Hölderich, W. F. J. Catal. 2003, 218, 315.

Autino, J. C. et. al. Tetrahedron Lett. 2004, 45, 8935.

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TFA Catalyzed Pechmann CondensationTFA Catalyzed Pechmann CondensationTFA Catalyzed Pechmann CondensationTFA Catalyzed Pechmann Condensation

OH

R OEt

O OO O

R

+

TFA3.5 e.q.

reflux0.25 ~ 20 h

phenol £]-carbonyl ester 30% ~100%

Woods, L. L.; Sapp, J. J. Org. Chem. 1962, 27, 3703.

Phenol used: Phloroglucinol, 2-Methylresorcinol, Resorcinol, Orcinol, 4-Chlororesorcinol, Pyrogallol, 3-Hydroxydiphenyl amine

β-carbonyl esters used: Ethyl benzoyl acetate

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Indium(III) Chloride Catalyzed Indium(III) Chloride Catalyzed Pechmann CondensationPechmann Condensation

Indium(III) Chloride Catalyzed Indium(III) Chloride Catalyzed Pechmann CondensationPechmann Condensation

OH

R OEt

O OO O

R+

InCl3(10 mol%)

65 ~ 130 oC30 ~ 240 min

phenol ethyl acetoacetate 55% ~ 98%

Bose, D. S.; Rudradas, A. P.; Babu, M. H. Tetrahedron Lett. 2002, 43, 9195.

Phenol used: Resorcinol, Orcinol, 4-, Pyrogallol, 3-Hydroxydiphenyl amine, 3-methoxyphenol, 1,3,5-trihydroxybenzene, phenol, 1-naphthol

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POClPOCl33 Catalyzed Pechmann Condensation Catalyzed Pechmann Condensation in Neutral Ionic Liquids in Neutral Ionic Liquids

POClPOCl33 Catalyzed Pechmann Condensation Catalyzed Pechmann Condensation in Neutral Ionic Liquids in Neutral Ionic Liquids

OH

ROEt

O O O O

R+

POCl3(30 mol%)

[bmim]PF6

30 ~ 100 oC, 40 ~ 60 minphenol ethyl acetoacetate 47% ~ 95%

Potdar, M. K.; Rasalkar, M. S.; Mohile, S. S.; Salunkhe, M. M. J. Mol. Catal. A Chem. 2005, 235, 249.

Phenol used: Resorcinol, 2-Methylresorcinol, Orcinol, Pyrogallol, 1,3,5-trihydroxybenzene, 2',4'-Dihydroxyacetophenone

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Yb(OTf)Yb(OTf)3 3 Catalyzed Pechmann Condens Catalyzed Pechmann Condensationation

Yb(OTf)Yb(OTf)3 3 Catalyzed Pechmann Condens Catalyzed Pechmann Condensationation

OHR

O OR+

O

O

O

O

H

OMeYb(OTf)3

(10 mol%)

CH3NO2

100oC, 1.5h 31% ~ 88%

Fillion, E. et. al. J. Org. Chem. 2006, 71, 409.

Phenol used: 3,5-dimethoxyphenol, 3,4-dimethoxyphenol, sesamol, 3-methoxy-2-methylphenol

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Microwave acceleration of the Pechmann reacMicrowave acceleration of the Pechmann reaction on graphite/montmorillonite K10tion on graphite/montmorillonite K10

Microwave acceleration of the Pechmann reacMicrowave acceleration of the Pechmann reaction on graphite/montmorillonite K10tion on graphite/montmorillonite K10

H2N OHH3CO

OCH3

OO

O OH2N

COOCH3

O

130oC+

Experimental Experimental conditionsconditions

Conventional heatingConventional heating Microwave irradiationMicrowave irradiation

Reaction Reaction time (min)time (min)

YieldYield

(%)(%)Reaction Reaction

time (min)time (min)YieldYield

(%)(%)

Neat (fusion)Neat (fusion) 120120 3636 8585 3939

Support: graphiteSupport: graphite 120120 4444 5050 4444

Support: Support:

graphite:K10 (2:1)graphite:K10 (2:1)a, a,

bb

6666 6464 3030 6666

a. No modifications were observed when a preliminary activation (2 h at 180°C) of the clay was realized.

b. No significant results were observed in the absence of graphite (montmorillonite K10 + phenol + b-ketoester).

Fre`re, S.; Thie´ry, V.; Besson, T. Tetrahedron Lett. 2001, 42, 2791.

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Wells–Dawson heteropolyacid Catalyzed Wells–Dawson heteropolyacid Catalyzed Pechmann Condensation Pechmann Condensation

Wells–Dawson heteropolyacid Catalyzed Wells–Dawson heteropolyacid Catalyzed Pechmann Condensation Pechmann Condensation

+OH

R H3CCOOEt

X

OO O

CH3

X

R

X = H, CH3

H6P2W18O62¡D24H2O

toluene, refluxor

sovent-free, 130oC

1 mol%

38% ~ 97%

Romanelli,G. P.; Bennardi, D.; Ruiz, D. M.; Baronetti, G.; Thomas, H. J.; Autino, J. C.Tetrahedron Lett. 2004, 45, 8935.

Phenol used: resorcinol, phloroglucinol, 3-methoxyphenol, pyrogallol, 3,4-dimethylphenol, 3-methylphenol, orcinol, 1-naphthol

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Synthesis of Coumarins by Grubbs’ Synthesis of Coumarins by Grubbs’ CatalystCatalyst

Synthesis of Coumarins by Grubbs’ Synthesis of Coumarins by Grubbs’ CatalystCatalyst

Ph

N N

PCy3

Cl

ClRu

MeMe

Grubbs' catalystVan, T. N.; Debenedetti, S.; Kimpe, N. D. Tetrah

edron Lett. 2003, 44, 4199.

O

O

O

O5 mol% Grubbs' catalyst

CH2Cl2, reflux, 24 h

70%

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DDisadvantagesisadvantages of Brønsted Acids of Brønsted AcidsDDisadvantagesisadvantages of Brønsted Acids of Brønsted Acids

Proton Donor Brønsted AcidsProton Donor Brønsted Acids

– Catalysts have to be used in excess, for example sulfuric acid, 10–12 equiv, trifluoroacetic acid, 3–4 equiv.

– Longer reaction time and very often temperatures to be excess 150 oC and above.

– Their corrosive nature and the formation of several side products make them difficult to handle.

– The disposal of acidic waste leads to environmental pollution.

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DDisadvantagesisadvantages of Traditional and of Traditional and Lanthanide Lewis Acid Lanthanide Lewis Acid

DDisadvantagesisadvantages of Traditional and of Traditional and Lanthanide Lewis Acid Lanthanide Lewis Acid

Traditional Lewis Acid CatalystsTraditional Lewis Acid Catalysts– Many chlorinated derivatives are highly moisture sensitive

and hydrolyse rapidly under conventional storage or standard reaction conditions.

– The disposal of acidic waste leads to environmental pollution.

– Can not control electronic and steric environments around metal Lewis acid center.

Lanthanide Lewis Acid CatalystsLanthanide Lewis Acid Catalysts– Lanthanide metals are relatively rare.

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MotivationMotivationMotivationMotivation

Low Oxidation State Transition MetalsLow Oxidation State Transition Metals– Relatively high moisture – and oxygen – stability – Inexpensive– Tunable electronic and steric environments around metal ce

nter

GreenGreen ChemistryChemistry– Greener solvents

R.T. ionic liquids, [Bmim]PF6

– Energy saving Catalysis under microwave flash heating replace thermal heating– Recyclable catalyst

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Preparation of Organomolybdenum CatalystPreparation of Organomolybdenum CatalystPreparation of Organomolybdenum CatalystPreparation of Organomolybdenum Catalyst

Thermal Thermal conditionsconditions

N NN

Mo

OCCOOC

P

O

2 eq NOBF4

0oC / stir 1 hr NN

N

Mo

ONNOOC

P

O2+

(BF4-)2

dry CH3NO2

75% yield

NN

N

N NN

Mo

OCCOOC

P

O

reflux (82oC) / 18 hrdry CH3CN

MoCO

COCO

COOC

OCP

O

80% yield

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Crotonaldehyde-Lewis Acid AdductCrotonaldehyde-Lewis Acid AdductCrotonaldehyde-Lewis Acid AdductCrotonaldehyde-Lewis Acid Adduct

H3

O

H2

O

H3

L.A.O

L.A.

H1

H2

CH34

L.A.

H3

CH34

H1 H1

H2

CH34

H2

O

H3

CH34

H1

L.A.

CH34

H3

H2

H1O

L.A.

H3

CH34

H2

H1 OL.A.

11H chemical shiftH chemical shift HH11 H H22 HH33 H H44

crotonaldehydecrotonaldehyde

crotonaldehyde + crotonaldehyde + Cat.Cat.

9.41 6.08 7.01 9.41 6.08 7.01 2.032.03

9.89 6.71 8.14 9.89 6.71 8.14 2.322.32

Chemical shift diff.Chemical shift diff. 0.48 0.63 0.48 0.63 1.131.13 0.290.29

Childs, R. F. et. al. Can. J. Chem. 1982, 60, 801.

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Lewis acid △δ on H3 (ppm)BBr3 1.49

AlCl3 1.23

[OP(2-Py)3W(CO)(NO)2](SbF6)2 1.23

[OP(2-Py)3W(CO)(NO)2](BF4)2 1.22

[P(2-Py)3W(CO)(NO)2](SbF6)2 1.21

[HOC(2-Py)3W(CO)(NO)2](SbF6)2 1.19

[P(2-Py)3W(CO)(NO)2](BF4)2 1.18

BF3 1.17

AlEtCl2 1.15

[OP(2-Py)3Mo(CO)(NO)2](BF4)2 1.13

[HC(2-Py)3Mo(CO)(NO)2](SbF6)2 1.05

TiCl4 1.03

[P(2-Py)3Mo(CO)(NO)2](BF4)2 0.99

[Me3P(CO)3(NO)W]+ 0.93

SnCl4 0.87

[CpMo(CO)2]+(PF6) 0.70

Et3Al 0.63

[CpFe(CO)2]+BF4 0.54

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Spectral Data of CO Coordinated Spectral Data of CO Coordinated CatalystsCatalysts

Spectral Data of CO Coordinated Spectral Data of CO Coordinated CatalystsCatalysts

Organometalliccompound

chemical shift

(13C NMR)

IR absorption band

[OP(2-py)3W(CO)(NO)2](BF4)2 190.5 ppm 2156 cm-1/ nujol

[P(2-py)3W(CO)(NO)2](SbF6)2 192.0 ppm 2143 cm-1/ nujol

[P(2-py)3W(CO)(NO)2](BF4)2 192.2 ppm 2148 cm-1/KBr

Vapor CO 2143 cm-1

Mo(CO)6 202.3 ppm 2115,1983 cm-1/nujol

W(CO)6 192.1 ppm 2110,1980 cm-1/KBr

[OP(2-py)3Mo(CO)(NO)2](BF4)2 223.0 ppm 2060 cm-1/KBr

[P(2-py)3Mo(CO)(NO)2](BF4)2 222.0 ppm 2046cm-1/KBr

OP(2-py)3Mo(CO)3 227.5 ppm 1910,1806 cm-1/nujol

P(2-py)3Mo(CO)3 227.3 ppm 1908,1797cm-1/CD3Cl

OP(2-py)3W(CO)3 222.1 ppm 1890 cm-1/ nujol

P(2-py)3W(CO)3 222.9 ppm 1880,1762 cm-1/KBr

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Organomolybdenum Lewis Acid Catalyzed Organomolybdenum Lewis Acid Catalyzed Pechmann Condensation Pechmann Condensation


Thermal Thermal conditionsconditionsOH

ROEt

O O O O

R+

phenol ethyl acetoacetate

[O=P(2-py)3Mo(CO)(NO)2](BF4)21 mol%

120 oC, neat or 0.5 ml solvent

Solvent system: [bmim]PF6 or CH3CN or DMF or CH3NO2 or THF

OHHO

OHO

OHHO

OHOHHO

OHHOOH

HO OH

OH

OH

NO2 OH

O2N

Phenol

Resorcinol 1,3,5-trihydroxybenzene

3-methoxyphenol

Orcinol2-methylresorcinol

2-nitrophenol 4-nitrophenol

1-naphthol

Pyrogallol

O O

OHO

OHO H2N OH

3,5-dimethoxyphenol 3-aminophenolsesamol

OH

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Ionic LiquidsIonic LiquidsIonic LiquidsIonic Liquids

Seddon, K. R. et. al. Pure Appl. Chem. 2000, 72, 2275.

22

Coordinative Characteristics of Various Coordinative Characteristics of Various Anions Anions

Coordinative Characteristics of Various Coordinative Characteristics of Various Anions Anions

Wasserscheid, P., et. al. Angew. Chem. Int. Ed. 2000, 39, 3772.

Cl-

AcO-

NO3-

SbF6-

BF4-

PF6-

Al2Cl7-

Al3Cl10-AlCl4

-

CuCl2-

basic/ stronglycoordinating

neutral/ weakly coordinating

acidic/non- coordinating

acidic/ coordination

SO42- Cu2Cl3

-

Cu3Cl4-

23

Room temperature ionic liquids exhibit many properties which make them potentially attractive media for homogeneous catalysis:

They have essentially no vapour pressure. They generally have reasonable thermal stabili

ty. They are able to dissolve a wide range of organi

c, inorganic and organometallic compounds. The solubility of gases. They are immiscible with some organic solvent

s. Ionic liquids have been referred to as ‘designe

r solvents’ by a suitable choice of cation / anion.

24

OH

ROEt

O O O O

R+

phenol ethyl acetoacetate120 oC, 48 h, neat

no catalyst

Entry PhenolYield (%)



1 n. d. 6 n. d. 11 n. d.

2 n. d. 7 n. d. 12 n. d.

3 n. d. 8 n. d. 13 n. d.

4 n. d. 9 n. d.

5 n. d. 10 n. d.

O O

OH

O

OHO

OHHO

OH

HO OH

OHO

OHHO

OH

OHHO

OH

NO2

OHHO

OH

OH

O2N

OH

H2N OH

25

OH

ROEt

O OO O

R+



120 oC, neat

Entry Phenol TimeYield (%)

Entry PhenolTime(h)

Yield (%)

1 1 h 98 8 10 h 82

225min

80 9 4 h 84

315min

75 10 24 h 81

415min

69 11 24 h n. d.

5 4 h 69 12 24 h n. d.

6 10 h 93 13 24 h n. d.

7 5 h 91

OHHO

OH

HO OH

OHHO

OHHO

OHHO

OH

O O

OH

O

OHO

OHO

OH

H2N OH

OH

NO2

OH

O2N

OH

26

OH

ROEt

O OO O

R+



120 oC, 0.5 ml solvent

Entry Phenol Time

Yield (%)

[Bmim]PF6

CH3NO2 THF CH3CN DMF

1 1 h 91 64 32 9 n. d.

2 24 h -- 86 54 24 3

325min

84

(20 min)12 5 4 n. d.

4 7 h -- 8242

(68)*40

(69)*n. d.(5)*

515min

82

(10 min)19 12 13 n. d.

6 2 h -- 83 81 8212

(79)*

OHHO

OH

HO OH

OHHO

OH

*After reacting 24 h, the products’ yield

27

OH

ROEt

O OO O

R+





[Bmim]PF6


715min

84 21 18 16 n. d.

8 2 h -- 82 80 80n. d.

(5)*

9 4 h82

(20 min)22 10 n. d. n. d.

10 24 h -- 60 26 5 n. d.

OHHO

OHHO

*After reacting 24 h, the products’ yield

28

OH

ROEt

O OO O

R+





[Bmim]PF6


11 10 h92

(6 h)31 21 6 n. d.

12 24 h -- 54 40 12 n. d.

13 5 h93

(1 h)43 14 11 n. d.

14 24 h -- 82 68 52 15

15 10 h88

(5 h)18 10 11 n. d.

16 24 h -- 34 24 28 n. d.

O O

OH

O

OHO

OHO

29

OH

ROEt

O OO O

R+





[Bmim]PF6


17 4 h92

(2 h)75 64 65 61

18 6 h -- 92 88 90 77

19 8 h -- -- -- -- 82

20 10 h 88 16 10 5 n. d.

21 24 h -- 38 23 14 n. d.

OH

H2N OH

30

OH

ROEt

O OO O

R+




Entry Phenol Time

Yield (%)

[Bmim]PF6


22 24 h n. d. n. d. n. d. n. d. n. d.

23 24 h n. d. n. d. n. d. n. d. n. d.

24 24 h n. d. n. d. n. d. n. d. n. d.

OH

NO2

OH

O2N

OH

31

Entry

Phenol

Yield (%)Entr

yPhenol

Yield (%)

neat[Bmim]PF

6neat

[Bmim]PF6

1 98(1 h)

91 (1 h)

69 (20 min)8

82(10 h)

88

(5 h)

2 80(25 min)

84(20 min) 9

84(4 h)

92

(2 h)

375

(15 min)82

(10 min) 1081

(24h)88

(10 h)

4 69(15 min)

84(15 min) 11 n. d.

(24 h)n. d.

(24 h)

5 69(4 h)

82(20 min) 12 n. d.

(24 h)n. d.

(24 h)

6 93(10 h)

92(6 h) 13 n. d.

(24 h)n. d.

(24 h)

791

(5 h)

93 (1 h)

71 (20 min)

OHHO

OH

HO OH

OHHO

OHHO

OHHO

OH

O O

OH

O

OHO

OHO

OH

H2N OH

OH

NO2

OH

O2N

OH

OH

ROEt

O OO O

R+



120 oC

32

Thermal HeatingThermal Heating

Convection transition

Liquid boiling temperature is always lower than surface temperature of container

33

Mechanism of Microwave Heating

Dipole RotationDipole Rotation

34

Ionic Ionic ConductionConduction

35

Interactive Characteristic between Interactive Characteristic between Materials and MicrowaveMaterials and Microwave

Conductor (Metal Material)

Reflective

Insulator (Telflon) Transparen

t

Dielectric Materials (Water)

Absorptive

36

Microwave Flash HeatingMicrowave Flash Heating

Microwave energy

Liquid raises temperature quickly

Digestion bottle

37

Preparation of Organomolybdenum CatalystPreparation of Organomolybdenum Catalyst

Microwave Flash Heating ConditionsMicrowave Flash Heating Conditions

NN

N

NN

N

Mo

OC

COOC

P

O

uw(300W/100%)/ 120 oC/ 5 min

dry CH3CN

MoCO

CO

CO

COOC

OCP

O

90 % yield

NN

N

Mo

OC

COOC

P

O

2 eq NOBF4

0oC / stir 1 hrN

NN

Mo

ON

NOOC

P

O2+

(BF4-)2

dry CH3NO2

75 % yield

38



Microwave Flash Heating ConditionsMicrowave Flash Heating Conditions

OHHO

OHO

OHHO

OHOHHO

OHHOOH

HO OH

OH

OH

NO2 OH

O2N

Phenol

Resorcinol 1,3,5-trihydroxybenzene

3-methoxyphenol

Orcinol2-methylresorcinol

2-nitrophenol 4-nitrophenol

1-naphthol

Pyrogallol

O O

OHO

OHO H2N OH

3,5-dimethoxyphenol 3-aminophenolsesamol

OH

OH

ROEt

O O O O

R+



mw, 120 oCneat or 0.5 ml [bmim]PF6

39

OH

ROEt

O O O O

R+



mw, 120 oCneat or 0.5 ml [bmim]PF6

Entry

Phenol

Yield (%)Entr

yPhenol

Yield (%)

neat[Bmim]PF

6neat

[Bmim]PF6

1 93(7 min)

86(7 min) 8

80(15 min)

46

(17 min)

2 92(5 min)

83(3 min) 9

86(10 min)

69

(10 min)

389

(3 min)91

(1 min) 1066

(17 min)17

(17 min)

4 86(6 min)

90(2 min) 11 n. d.

(17 min)n. d.

(17 min)

5 73(15 min)

84(3 min) 12 n. d.

(17 min)n. d.

(17 min)

6 93(17 min)

51(17 min) 13 n. d.

(17 min)n. d.

(17 min)

791

(15 min)

68

(17 min)

OHHO

OH

HO OH

OHHO

OHHO

OHHO

OH

O O

OH

O

OHO

OHO

OH

H2N OH

OH

NO2

OH

O2N

OH

40

Microwave Flash Heating and Microwave Flash Heating and Power Supply CurvePower Supply Curve

Microwave Flash Heating and Microwave Flash Heating and Power Supply CurvePower Supply Curve

OHO

OEt

O

R

Mo

Microwave Power Supply Curve

0

20

40

60

80

100

120

0 2 4 6 8 10 12 14 16 18

Time (min)

Po

we

r (%

)

IL IL + 3-OH-phenol + Et-acetateIL + phenol + Et-acetate 3-OH-phenol + Et-acetatephenol + Et-acetate

Microwave Flash Heating Curve

20

40

60

80

100

120

140

0 2 4 6 8 10 12 14 16 18Time (min)

Tem

p. (

deg

ree

cels

ius)

IL IL + 3-OH-phenol + Et-acetateIL + phenol + Et-acetate 3-OH-phenol + Et-acetate

phenol + Et-acetate

41

OH

ROEt

O O O O

R+



120 oCneat or 0.5 ml [bmim]PF6

Entry PhenolThermal / Yield (%) MW / Yield (%)

neat [Bmim]PF6 neat [Bmim]PF6

1 98(1 h)

91 (1 h)

69 (20 min)

93(7 min)

86 (7 min)

94 (8 min)

2 80(25 min)

84(20 min)

92(5 min)

83(3 min)

375

(15 min)82

(10 min)89

(3 min)91

(1 min)

4 69(15 min)

84(15 min)

86(4 min)

90(2 min)

5 69(4 h)

82(20 min)

73(15 min)

84(3 min)

OHHO

OH

HO OH

OHHO

OHHO

OHHO

OH

42

OH

ROEt

O O O O

R+






6 93(10 h)

92 (6 h)93

(17 min)51

(17 min)

791

(5 h)

93 (1 h)

71 (20 min)

91(15 min)

68

(17 min)

882

(10 h)

88

(5 h)

80(15 min)

46

(17 min)

984

(4 h)

92

(2 h)

86(10 min)

69

(10 min)

10 81(24 h)

88(10 h)

66(17 min)

17(17 min)

O O

OH

O

OHO

OHO

OH

H2N OH

43

Recyclability of Organomolybdenum Lewis AciRecyclability of Organomolybdenum Lewis Acid Catalystd Catalyst

Recyclability of Organomolybdenum Lewis AciRecyclability of Organomolybdenum Lewis Acid Catalystd Catalyst

CatalystSolution

Substrate Adduct

Added Extraction

Ionic Liquid[Bmim]PF6

CHCl3

44

Recyclability of Organomolybdenum LeRecyclability of Organomolybdenum Lewis Acid Catalyst in [bmim]PFwis Acid Catalyst in [bmim]PF66

Recyclability of Organomolybdenum LeRecyclability of Organomolybdenum Lewis Acid Catalyst in [bmim]PFwis Acid Catalyst in [bmim]PF66

OH

OEt

O OO O

+


120 oC[bmim]PF6

OO

Catalyst 1 Recycling in [Bmim]PF6

0102030405060708090

100

0 1 2 3 4 5 6 7

number of experiment

an

aly

tic

yie

ld (

%)

45

Proposed MechanismProposed MechanismProposed MechanismProposed Mechanism

N NN

P

MoNOOC

O

NO

2+

( BF4- )2

- CON NN

P

MoNO

O

NO

2+

( BF4- )2

OEt

O

N NN

P

MoNO

O

NO

2+

( BF4- )2

OEt

O

nucliphilic attack

OEt

O

O

O

RHO

RHO

O

£_+

Mo

46

Proposed MechanismProposed MechanismProposed MechanismProposed Mechanism

O

O OO

HO

OEt

O

R-EtOH

MoMo

O

O OH

Mo

OO

OH

Mo

£_+O

OH

O

H

Mo

O

O

O

O O

H

H

MoMichaeladdition -H+

+H+

N NN

P

MoNO

O

NO

2+

( BF4- )2+

R R

RR R

R

47

Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Pechmann Condensation

Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Pechmann Condensation

CatalystsCatalystsYield (%)Yield (%)

A(2-py)A(2-py)33 MM

O=P(2-py)O=P(2-py)33 MoMo 9898

P(2-py)P(2-py)33 MoMo 8282

O=P(2-py)O=P(2-py)33 WW 7474

P(2-py)P(2-py)33 WW 7171

OH

OEt

O OO O

+

[A(2-py)3M(CO)(NO)2](BF4)21 mol%

120 oCneat, 1h

HO HOOH

OEt

O OO O

+


120 oCneat, 1h

HO HO

48

Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Mukaiyama Aldol Reaction

Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Mukaiyama Aldol Reaction

CatalystsCatalystsYield (%)Yield (%)

A(2-py)A(2-py)33 MM

O=P(2-py)O=P(2-py)33 MoMo 9393

P(2-py)P(2-py)33 MoMo 8585

O=P(2-py)O=P(2-py)33 WW 5656

P(2-py)P(2-py)33 WW 4545

李婉甄碩士論文 ‘有機鉬金屬路易士酸在微波中對於 Mukaiyama Aldol 反應催化活性之探討’ 中正大學化學研究所 , 2005.

Cl3C

O

Si(CH3)3

DMF, 40oC, 5h

10 mol%Cl3C

OH[A(2-py)3M(CO)(NO)2](BF4)2

49

Catalytic Reactivity of [A(2-py)Catalytic Reactivity of [A(2-py)33M(CO)M(CO)(NO)(NO)22]]2+ 2+ on Diels Alder Reactionon Diels Alder Reaction

Catalytic Reactivity of [A(2-py)Catalytic Reactivity of [A(2-py)33M(CO)M(CO)(NO)(NO)22]]2+ 2+ on Diels Alder Reactionon Diels Alder Reaction

CatalystsCatalystsConcentration (M)Concentration (M)

/Time (min)/Time (min) Yield (%) (endo: exo)Yield (%) (endo: exo)A(2-py)A(2-py)33 MM

O=P(2-O=P(2-py)py)33

aa WW 0.67 / 450.67 / 45 97 (90:10)97 (90:10)

O=P(2-py)O=P(2-py)33bb MoMo 0.67 / 450.67 / 45 85 (90:10)85 (90:10)

P(2-py)P(2-py)33cc WW 0.022 / 300.022 / 30 87 (94:6)87 (94:6)

a: 陳宜宏碩士論文 “水溶性有機鎢金屬路易士酸在綠色溶劑及微波中對於 Diels-Alde 反應的影響”中正大學化學研究所 , 2003.

b: 李婉甄碩士論文 ‘有機鉬金屬路易士酸在微波中對於 Mukaiyama Aldol 反應催化活性之探討’ 中正大學化學研究所 , 2005.

c: 傅耀賢博士論文 “過渡金屬錯合物觸媒的合成、催化活性以及動力學研究中正大學化學研究所 , 2001

bmimPF6


O

O

50

ConclusionsConclusionsConclusionsConclusions

We have successfully demonstrated the catalytic activity of [O=P(2-py)3Mo(CO)(NO)2](BF4)2 for the synthesis of a variety of coumarins under solvent-free and ionic liquid system ([Bmim]PF6) conditions. This practical and simple method led to good yields of the coumarin derivatives under mild conditions and within short times.

The time economy, along with the conservation of the organomolybdenum Lewis acid catalyst activity and the high recovery of the Lewis acid catalyst, play for both low environmental impact and low cost. Other green advantages of the procedure are the low formation of wastes, easy purification; and principally, the replacement of corrosive and environmental unfriendly acids.

51

ConclusionsConclusionsConclusionsConclusions

The successful use of microwave irradiation in providing this rapid and direct route to coumarins in comparison to classical procedures contributes to confirming the participation of specific effects in some microwave-assisted organic synthesis.

Because the [O=P(2-py)3Mo(CO)(NO)2](BF4)2 catalyst is relatively high moisture – and oxygen – stability, we use neutral ionic liquids, [Bmim]PF6, for Pechmann condensation as a recyclable media, and still have good yield for several times.

52

OH

ROEt

O O O O

R+






11 n. d.(24 h)

n. d.(24 h)

n. d. (17 min)

n. d. (17 min)

12 n. d.(24 h)

n. d.(24 h)

n. d. (17 min)

n. d. (17 min)

13 n. d.(24 h)

n. d.(24 h)

n. d. (17 min)

n. d. (17 min)

OH

NO2

OH

O2N

OH

1 recyclable organomolybdenum lewis acid catalyst and microwave assisted pechmann condensation...

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