Electronic Supplementary Material (ESI) for RSC Advances.

This journal is © The Royal Society of Chemistry 2014

Supporting Information

Deprotection of oximes, imines, and azines to the

corresponding carbonyls using Cu-nano particles on cellulose
template as green reusable catalyst

Diganta Baruah,a Ujwal Pratim Saikia,a Pallab Pahari,a* Dipak Kumar Duttab and Dilip

Konwara*

a. Synthetic Organic Chemistry Division, CSIR-North East Institute of Science and

Technology, Jorhat, Assam, India, 785006.

b. Materials Science Division, CSIR-North East Institute of Science and Technology, Jorhat,
Assam, India, 785006.

Email: ppahari@gmail.com, dkonwar@yahoo.co.uk

Table of Contents

Experimental ……………..………………………………………………….……………………………..…………… S2
Spectra ……………………………………………………………………………………………….…………………….. S11

S1
Experimental

General Methods. Chromatographic separations were performed using silica gel 60-120.
Infrared (IR) spectra were recorded using an FT-IR spectrometer as chloroform solutions
on sodium chloride disks. NMR spectra were recorded in Bruker Avance DPX 300 MHz and
Avance-III 500 MHz FTNMR spectrometer using tetramethylsilane (TMS) as an internal
standard in indicated solvent. All microwave irradiation experiments were carried out in a
CEM-Discover LabMate system (standard configuration, temperature control, external IR
temperature sensor, fixed hold time).

Preparation of Cu-nano particle using NaBH4 reduction method:

To a suspension of standard cellulose (200 mg) in water (20 mL), copper(II) acetate (50
mg) was added. The mixture was stirred for 30 minutes at room temperature and then
cooled to 0 °C. NaBH4 (20 mg) was added slowly portion wise under nitro gen atmosphere
when the solution turned black. The whole mixture was stirred at that temperature for
another 1 hour. The black suspension was filtered, washed, vacuum dried, and finally
stored under N2 atmosphere.

Preparation of Cu-nano particle using hydrazine hydrate/ NaOH reduction method

To a suspension of standard cellulose (200 mg) in water (20 mL), copper(II) acetate (50
mg) was added and the mixture was stirred for 30 minutes at room temperature. NaOH
(10%) solution and Hydrazine Hydrate was added to the above suspension until the pH
value exceeds 10. The resulting solution was kept in a thermostatic bath (50-60 °C) for 3-4
h. The black suspension was then filtered, washed and vacuum dried and finally stored
under N2 atmosphere.

General procedure for deprotection of oximes/imines/azines

In a 10 mL microwave reaction vial oxime/imine/azine (1 mmol), H2O (5 mL), and Cu-nano

catalyst (20 mol%) were taken. The mixture was heated under microwave at 80–100 oC for
5-10 min. After the completion of the reaction, as checked by TLC, the catalyst was filtered
while washing with ethyl acetate. The filtrate was extracted with ethyl acetate (2 × 20 mL).

S2
The organic layer was washed with brine (15 mL), dried over anhydrous Na2SO4,
concentrated, and purified by column chromatography.

General procedure for preparation of oximes:

To a solution of aldehyde/ketone (1 mmol) in ethanol (5 mL), hydroxylamine (1.5 mmol)

and pyridine (0.5 mL) was added. The mixture was heated on a water bath at 70-80 °C for
30 minutes to 3 hours. After this, the reaction was cooled in an ice batch when crystals of
oximes separated. Filtration and washing with 70% cold ethanol provided oxime. Further
purification was done by recrystallization from ethanol (95%).

General procedure for preparation of imines and azines:

A mixture of aldehyde (1 mmol), amine (1 mmol), and ethanol (5 mL) was warmed in a
water bath for 2-5 minutes and then cooled in an ice bath when crystals of imines/azines
separated. Filtration, washing with 70% ethanol and recrystallization from ethanol (95%)
provided pure imines/azines.

Characterization of aldehydes:

Cl CHO

2a

4-Chlorobenzaldehyde (2a). Semi solid; Rf: 0.6 (1:20 :: Ethyl acetate:Hexane); IR (KBr):
cm-1 1699, 1589, 1386, 1207, 1094; 1H NMR (CDCl3, 300 MHz): δ 9.99 (s, 1H), 7.84 (d, 2H, J
= 8.4 Hz), 7.52 (d, 2H, J = 8.4 Hz).

Cl CHO

2b Cl

2, 4-Dichlorobenzaldehyde (2b). Solid; Mp: 68-70 °C (lit.1 71-72 °C); Rf: 0.75 (1:20 :: Ethyl
acetate:Hexane); IR (KBr): cm-1 1678, 1584, 1375, 1199, 1047; 1H NMR (CDCl3, 300 MHz): δ
10.42(s, 1H), 7.87 (d, 2H, J = 8.4), 7.49(s, 1H), 7.38 (d, 2H, J = 8.4).

S3
 NO2

CHO

2c

2-Nitrobenzaldehyde (2c). Semi solid; Rf: 0.6 (1:10 :: Ethyl acetate:Hexane); IR (KBr): cm-
1 1694, 1524, 1344, 1188; 1H NMR (CDCl3, 500 MHz): δ 10.43 (s, 1H), 8.13 (dd, 1H, J = 8.0,
1.5 Hz), 7.96 (d, 1H, J = 8.0, 1.5 Hz), 7.88-7.71 (m, 2H).

Me2N CHO

2d

4-(Dimethyl)aminobenzaldehyde (2d). Solid; Mp: 70-72 °C (lit.2 70-72 °C); Rf: 0.4 (1:10 ::
Ethyl acetate:Hexane); IR (KBr): cm-1 1661, 1598, 1375, 1231, 1170, 1065; 1H NMR (CDCl3,
300 MHz): δ 9.74(s, 1H), 7.75 (d, 2H, J = 8.7), 6.72 (d, 2H, J = 8.7 Hz), 3.087(s, 6H).

CHO

2e OH

Salicylaldehyde (2e). Oil; Rf: 0.6 (1:20 :: Ethyl acetate:Hexane); IR (KBr): cm-1 3062, 1664,
1580, 1459, 1386, 1278, 1150, 1029; 1H NMR (CDCl3, 300 MHz): δ 11.02 (s, 1H), 9.89 (s,
1H), 7.58 -7.50 (m, 2H), 7.05-6.96 (m, 2H).

OHC CHO

2f

Benzene-1,4-dicarbaldehyde (2f). Solid; Mp: 110-112 °C (lit.3 113-114 °C); Rf: 0.5 (1:5 ::
Ethyl acetate:Hexane); IR (KBr): cm-1 1692, 1497, 1384, 1301, 1199, 1013; 1H NMR (CDCl3,
300 MHz): δ 10.14 (s, 2H), 8.06 (s, 4H).

S4
 CHO

N 2g

Pyridine-3-aldehyde (2g). Oil; Rf: 0.3 (1:10 :: Ethyl acetate:Hexane); IR (KBr): cm-1 1704,
1590, 1428, 1216, 1026; 1H NMR (CDCl3, 300 MHz): δ 10.14 (s, 1H), 9.10 (s, 1H), 8.86 (d, 1H,
J = 8.0 Hz), 8.21 (d, 1H, J = 8.0 Hz), 7.54-7.44 (m, 1H).

2h

Cyclohexanone (2h). Oil; Rf: 0.7 (1:20 :: Ethyl acetate:Hexane); IR (KBr): cm-1 1714, 1450,
1311, 1222, 1119; 1H NMR (CDCl3, 300 MHz): δ 2.38-2.28 (m, 4H), 1.91-1.83 (m, 4H), 1.75-
1.68 (m, 2H).
O

NH2
2i

(2-Aminophenyl)(phenyl)methanone (2i). Solid; Mp: 101-103 °C (lit.4 103-104 °C); Rf:

0.65 (1:10 :: Ethyl acetate:Hexane); IR (KBr): cm-1 3470, 3349, 1615, 1548, 1303, 1248,
1160; 1H NMR (CDCl3, 300 MHz): δ 7.66 (d, 2H, J = 8.0 Hz), 7.58-7.45 (m, 4H), 7.32 (t, 1H, J =
8.0 Hz), 6.76 (d, 1H, J = 8.0 Hz), 6.62 (t, 1H, J = 8.0 Hz), 6.12 (s, 2H).

H3CO CHO

4d

4-Methoxy benzaldehyde (4d). Oil; Rf: 0.35 (1:20 :: Ethyl acetate:Hexane); IR (KBr): cm-1
1694, 1601, 1513, 1316, 1182, 1025; 1H NMR (CDCl3, 500 MHz): δ 9.88 (s, 1H), 7.84 (d, 1H, J
= 7.5 Hz), 7.02 (d, 1H, J = 7.5 Hz), 3.86 (s, 3H).

S5
 CHO

4e

Cinnamaldehyde (4e). Oil; Rf: 0.3 (1:20 :: Ethyl acetate:Hexane); IR (KBr): cm-1 1678,
1626, 1450, 1127, 973; 1H NMR (CDCl3, 500 MHz): δ 9.88 (d, 1H, J = 8.0 Hz), 7.98-7.52 (m,
2H), 7.48-7.40 (m, 4H), 6.71 (dd, 1H, J = 16.0, 8.0 Hz).

Characterization of oximes:

N OH
Cl

1a

4-Chlorobenzaldehyde oxime (1a). 1H NMR (CDCl3, 300 MHz): δ 8.12(s, 1H), 7.52 (d, 2H, J
= 9.0 Hz), 7.36 (d, 2H, J = 9.0 Hz).

N OH
Cl

1b Cl

2, 4-Dichlorobenzaldehyde oxime (1b). 1H NMR (CDCl3, 300 MHz): δ 8.28(s, 1H), 7.78 (d,
1H, J = 7.5 Hz), 7.42 (s, 1H), 7.25 (d, 1H, J = 7.5 Hz).

NO2

N OH
1c

2-Nitro benzaldehyde oxime (1c). 1H NMR (CDCl3, 300 MHz): δ 8.69(s, 1H), 8.07 (d, 1H, J =
7.0 Hz), 7.92 (d, 1H, J = 7.0 Hz), 7.71-7.53 (m, 2H).

S6
 OH
N

Me2N
1d

4-(Dimethylamino)benzaldehyde oxime (1d). 1H NMR (CDCl3, 500 MHz): δ 8.06 (s, 1H),
7.44 (d, 2H, J = 8.5 Hz), 6.68 (d, 2H, J = 8.5 Hz), 2.99 (s, 6H).

OH
N

OH
1e

2-Hydroxybenzaldehyde oxime (1e). 1H NMR (DMSO-d6, 500 MHz): δ 8.33 (s, 1H), 7.48
(d, 1H, J = 8.0 Hz), 7.28-7.18 (m, 1H), 6.98-6.75 (m, 2H).

N OH

HO N
1f

Benzene-1,4-dicarbaldehyde oxime (1f). 1H NMR (MeOH-d6, 300 MHz): δ 11.35 (s, 2H),
8.15 (s, 2H), 7.61 (s, 4H).

OH
N

N 1g

Nicotinaldehyde oxime (1g). 1H NMR (DMSO-d6, 500 MHz): δ 9.01 (s, 1H), 8.89-8.82 (m,
1H), 8.66-8.58(m, 1H), 8.34 (s, 1H), 7.99-7.94 (m, 1H).

OH
N

1h

Cyclohexanone oxime (1h). 1H NMR (CDCl3, 500 MHz): δ 2.52 (t, 2H, J = 6.5 Hz), 2.22 (t,
2H, J = 5.5 Hz), 1.72-1.55 (m, 6H).

S7
 OH
N

NH2
1i

(2-Aminophenyl)(phenyl)methanone oxime (1i). 1H NMR (CDCl3, 500 MHz): δ 7.63 (d,

2H, J = 7.0 Hz), 7.54-7.41 (m, 4H), 7.29 (t, 1H, J = 7.0 Hz), 6.73 (d, 1H, J = 8.0 Hz), 6.60 (t, 1H,
J = 7.0 Hz)

Characterization of imines:

N
Cl
3a

4-Chlorobenzylidene-phenylamine (3a). 1H NMR (CDCl3, 300 MHz): δ 8.42 (s, 1H), 7.84
(d, 2H, J = 8.3 Hz), 7.49-7.34 (m, 4H), 7.28-7.18 (m, 3H).

3b
OH

2-Phenyliminomethyl-phenol (3b). 1H NMR (CDCl3, 300 MHz): δ 13.28 (s, 1H), 8.62 (s,
1H), 7.55-7.25 (m, 5H), 7.03 (d, 1H, J = 8.4 Hz), 6.95 (t, 1H, J = 7.5 Hz).

N N

OH HO
3c

SalenH2 (3c). 1H NMR (CDCl3, 300 MHz): δ 13.23 (s, 2H), 8.36 (s, 2H), 7.32-7.21 (m, 4H),
6.95-6.82 (m, 4H), 3.93 (s, 4H).

S8
 N
H3CO
3d

4-Methoxybenzylidenephenylamine (3d). 1H NMR (CDCl3, 300 MHz): δ 8.38 (s, 1H), 7.84
(d, 2H, J = 8.7 Hz), 7.43-7.35 (m, 2H), 7.24-7.18 (m, 3H), 6.97 (d, 2H, J = 8.6 Hz), 3.87 (s, 3H).

3e

Phenyl-(3-phenyl-allylidene)-amine (3e). 1H NMR (CDCl3, 300 MHz): δ 8.27 (d, 1H, J =

6.4 Hz), 7.54 (d, 2H, J = 7.8 Hz), 7.53-7.33 (m, 5H), 7.25-7.07 (m, 5H).

Characterization of azines:

Cl
N N
Cl
3f

N,N'-Bis-(4-chlorobenzylidene)-hydrazine (3f). 1H NMR (CDCl3, 300 MHz): δ 8.61 (s, 2H),

7.77 (d, 4H, J = 8.4 Hz), 7.42 (d, 4H, J = 8.4 Hz).

HO

N
N
3g
OH

N,N'-Bis-(2-hydroxybenzylidene)-hydrazine (3g). 1H NMR (CDCl3, 300 MHz): δ 11.28

(brs, 2H), 8.64 (s, 2H), 7.37-7.26 (m, 4H), 7.04-6.85 (m, 4H).

S9
 N N

3h

N,N'-Bis-(3-phenylallylidene)-hydrazine (3h). 1H NMR (CDCl3, 300 MHz): δ 8.43-8.32 (m,

2H), 7.53-7.50 (m, 4H), 7.44-7.33 (m, 6H), 7.09-7.07 (m, 4H)

References:

1. X. R. Lianga, F. Shia, R. E. Chena, and W. K. Su, Org. Prep. Proc. Int., 2010, 42, 379.
2. R. Trotzki, M. M. Hoffmann, and B. Ondruschka, Green Chem., 2008, 10, 767.
3. G. Pelletier , W. S. Bechara , and A. B. Charette , J. Am. Chem. Soc., 2010, 132, 12817–
12819.
4. B. Zhao, and X. Lu, Tetrahedron Lett., 2006, 47, 6765.

S10
Spectra:

Cl CHO

Cl CHO

Cl

S11
 NO2

CHO

Me2N CHO

S12
 CHO

OH

OHC CHO

S13
 CHO

S14
 O

NH2

H3CO CHO

S15
CHO

S16
 N OH
Cl

N OH
Cl

Cl

S17
 NO2

N OH

OH
N

Me2N

S18
 OH
N

OH

N OH

HO N

S19
 OH
N

OH
N

S20
 OH
N

NH2

S21
 N
Cl

OH

S22
HC N N CH

OH HO

N
H3CO

S23
 N

Cl
N N
Cl

S24
 HO

N
N

OH

N N

S25
 Cl CHO

IR spectra of prepared 4-chlorobenzaldehyde

Cl CHO

IR spectra of standard 4-chlorobenzaldehyde

S26