Capto-Dative Acylenamines in the Reactions with Dialkyl Hydrogen Phosphites: One-Pot Transformation of α-Formylated Enamines to the Esters of N,N'-Disubstituted α-Aminoacids

Article abstract of DOI:10.1023/A:1014232124751

α-Acylenamines with terminal double bond CH2=CH(NR2)COMe add dialkyl hydrogen phosphites to form only the Michaelis adducts. Contrary to that hydrophosphorylation of α-formylated enamines proceeds regiospecifically at C=O bond. Subsequent isomerization of

Full text of DOI:10.1023/A:1014232124751

Russian Journal of General Chemistry, Vol. 71, No. 12, 2001, pp. 1891 1895. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 12, 2001,
pp. 1996 2000.
Original Russian Text Copyright
2001 by Rulev, Larina, Voronkov.
Capto-Dative Acylenamines in the Reactions
with Dialkyl Hydrogen Phosphites:
One-Pot Transformation of -Formylated Enamines
to the Esters of N,N-Disubstituted -Aminoacids
A. Yu. Rulev, L. I. Larina, and M. G. Voronkov
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received February 19, 2000
Abstract
-Acylenamines with terminal double bond CH =CH(NR )COMe add dialkyl hydro-
2 2
gen phosphites to form only the Michaelis adducts. Contrary to that hydrophosphorylation of -formylated
enamines proceeds regiospecifically at C=O bond. Subsequent isomerization of the products of 1,2-addition
and the cleavage of P C bond of the intermediate -keto- -aminophosphonate yields N,N-disubstituted
-
aminocarboxylates.
After the discovery of unexpected transformation
of -formylated enamines to thioloesters of -amino-
with equimolar amounts of dialkyl hydrogen phosphi-
tes IIa IIc was carried out at room temperature
acids [1] further development of the procedure permit- without a solvent in the presence of the concentrated
ting the easy creation of CH(NR )CO group
solution of sodium alcoxylate similarly to the proce-
dure developed for , -unsaturated carbonyl com-
pounds [6 8]. It occured that the behavior of -acylen-
amines I principally differs from the observed in the
series of unsubstituted aldehydes and ketones [9] and
considerably depends on the structure of substrate.
Hence, 2-diethylaminobenzalacetophenone Ia does not
react with dimethyl hydrogen phosphite IIa. About
75% of enaminoketone was returned after carrying
out the reaction under optimal conditions and sub-
siquent distillation of reaction mixture. Inertness of
the starting ketone arises evidently from the great
steric hindrances to the attack of reagent on the double
bond C=C as well as on the carbonyl group of sub-
strate. Addition of the same phosphite IIa to 3-piperi-
dino-3-buten-2-one Ib having not the internal, but the
terminal double bond proceeds smoothly and stereo-
specifically. Even the traces of 1,2-adduct were not
observed (Scheme 1). Such unusual from the first
glance Michaelis addition of nucleophiles to this type
of systems was previously reported [10].
2
became actual. We have studied its applicability for
preparing of -aminocarboxylates with tertiaty amino
groups interesting as biologically active com-
pounds and synthones for preparing of polyfunctional
compounds.
But
the
chemistry
of
N,N-
disubstituted -aminoacids and their derivatives is
not widely reported about. At the same time these
compounds exhibit various pharmacological activity
and are considered to be the precursors of new
medicinal preparations [2 4].
Recently we have reported about the principal
possibility of preparing of N,N-disubstituted -amino
carboxylates from -formylated enamines and dialkyl
hydrogen phosphites [5]. The main goal of this work
became the investigation of the reaction of dialkyl hyd-
rogen phosphites II with capto-dative acylenamines I.
Besides the synthetic aspect of the problem we con-
sidered studying the mechanism of this reaction.
Reaction of -formyl- and -acylenamines Ia If
Scheme 1.
O
O
(
MeO) P(O)
2
MeONa/MeOH
N
N
+ (MeO) P(O)H
2
Ib
IIa
III
1
070-3632/01/7112-1891$25.00 2001 MAIK Nauka/Interperiodica

1
892
RULEV et al.
Scheme 2.
1
2
1
2
1
2
1
2
I, R = Me, NR = N(CH ) (c); R = Me, NR = N(CH CH ) O (d); R = Pr, NR = N(CH ) (e); R = Ph, NR = NEt
2
2 5
2
2
2 2
2
2 5
2
2
3
1
3
2
1
2
3
1
(
f). II, R = Me (a), Et (b), Pr (c). IV, R = R = Me, NR = N(CH ) (a); R = Me, NR = N(CH ) , R = Et (b); R =
2 2
2 5 2 5
R = Me, NR = N(CH CH ) O (c); R = Pr, NR = N(CH ) , R = Me (d); R = Ph, NR = NEt , R = Et (e).
3
2
1
2
3
1
2
3
2
2
2 2
2
2 5
2
2
Deshielding of the carbonyl carbon atom at the
transfer to formyl derivatives of enamines Ic If
creates the conditions for the successful addition of
phosphite II by C=O bond. But instead of the expec-
ted 1,2-adducts the esters of N,N-disubstituted
from substrates Ic If having alkyl (Me, Pr) or aryl
(Ph) substituents in -position. Result of this reaction
does not depend on the nature of substituents at nitro-
gen. Varying of structure, cyclic (piperidine, mor-
pholine) or acyclic (diethylamine), and the basicity of
the amine fragment from high (piperidine, diethyl-
amine) to moderate (morpholine) does not considerab-
ly influence the direction and the effectiveness of this
reaction.
-
aminoacids IV were isolated in 30 40% yield
(
Scheme 2).
Moderate yields of esters IV are explained by the
parallel proceeding of anionic polymerization either
of the starting substrate or of one of the intermediates
under the action of alcoxylate. In the absence of
catalyst no reaction between the phosphite II and
We have not studied in detail the pathway of this
interesting transformation. But published data and
obtained results permit to offer a scheme easily ex-
plaining the genesis of the starting esters IV. Ana-
logous sequence of transformations was considered
by us previously in connection with the formation of
thiol esters from the same substrates Ic If [1].
-formylated enamines Ic If was observed.
The preparation of esters of N,N-disubstituted
aminoacids was carried out with equal success
-
Scheme 3.
The first stage undoubtedly includes nucleophilic
in compounds of such structure the cleavage of P C
bond proceeds quite easily under the action of nucleo-
philic reagents such as amines, alcohols, or alcoho-
lates [11, 12]. This transformation directly leads to the
final ester IV.
addition of sodium dialkyl phosphite to the carbonyl
group of starting substrate Ic If. The key stage of all
the sequence of transformations from our point of
view is the isomerization of primarily formed
1
,2-adduct V to thermodinamically more stable
olefin VI. Obtained enol in turn quickly converts
to -keto- -aminophosphonate VII. It is known that
The ponderable approvement of the proposed reac-
tion mechanism may be the isolation of enol VI in a
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 12 2001

CAPTO-DATIVE ACYLENAMINES IN THE REACTIONS
1893
form of its stable derivative, for example of the cor-
responding silyl ether obtained by the reaction of
of equimolar amounts of compounds Ie and VIII in a
sealed ampule at 95 C for 2 h or at microwave irradia-
tion for 10 min results in formation of silyl ester X
(Scheme 4). The motive forse of isomerization of
olefin IX to enolosilyl ether X is the stabilizing effect
of three heteroatoms at the double bond of the latter.
-formylated enamine Ic-f and dimethyl(trimethyl-
silyl) phosphite VIII. The latter reacts with , -un-
saturated aldehydes and ketones to give the products
of 1,2- and (or) 1,4-addition [13, 14]. Really, reaction
Scheme 4.
From the point of view of the proposed scheme
phosphite II, used in the reaction, favors the vicarious
addition of alcohol. The first example of vicarious
nucleophilic addition was recently described by the
workers [15]. Really, performing the reaction of di-
propyl hydrogen phosphite IIc with enamine Ic in the
presence of sodium methylate in methanol under the
optimized conditions leads mainly to methyl 2-piperi-
dinobutanoate IVa. Hence, a new methodology of
one-pot synthesis of the derivatives of N,N-disubsti-
tuted -amino acids on the basis of -formylated
moved from filtrate. A solution of 0.2 g of sodium in
20 ml of methanol was added to the residue, and
resulting mixture left for a day at room temperature.
Then 10 ml of water was added, and obtained mixture
was extracted with ether (5 50 ml). Etherial extracts
were dried over magnesium sulfate. After removing
of solvent and vacuum distillation 0.6 g (22%) of
3-piperidino-3-buten-2-one Ib was obtained, bp 43
1
44 C (1 mm). IR spectrum, , cm : 1585 (C=C),
1
1698 (C=O). H NMR spectrum, , ppm: 1.45 1.70 m
(6H, , -CH of piperidine), 2.30 s (3H, CH CO),
2
3
enamines is developed, and the scheme, satisfactory 2.70 2.75 m (4H, -CH of piperidine), 4.47 d (1H,
2
1
3
describing its mechanism is offered.
=CH , J 0.9 Hz), 4.87 d (1H, =CH , J 0.9 Hz).
C
2
2
NMR spectrum, , ppm: 24.16, 25.68 (CH , piperi-
C
2
EXPERIMENTAL
dine), 27.69 (CH ), 50.66 (NCH ), 98.52 (=CH ),
3
2
2
1
57.34 (=C N), 200.54 (C=O). Mass spectrum, m/z
+
IR spectra were recorded on a Specord IR-75 spect-
(I , %): 153 M (41), 152(34), 110 (100), 54 (44),
rel
1
13
rometer in thin layer. H and C NMR spectra were
recorded on a Bruker DPX-250 spectrometer (400 and
43 (42). Found, %: C 70.55, H 9.87, N 9.14. C H
9
15
NO. Calculated, %: C 70.55; H 9.87; N 9.14.
1
00 MHz respectively) in CDCl at room temperature.
3
1
3
The attribution of signals in C NMR spectrum was
carried out with the DEPT procedure. Mass spectra
Reaction of 2-piperidino-3-buten-2-one (Ib) with
dimethyl hydrogen phosphite. To a mixture of rea-
were recorded on a Hewlett-Packard HP 5971A gents consisting of 0.20 g of 3-piperidino-3-buten-2-
(
70 eV) spectrometer.
one Ib and 0.15 g of dimethyl hydrogen phosphite IIa,
placed in a Claisen flask 7 drops of saturated solution
of sodium methylate in methanol was added. Result-
ing mixture was kept at room temperature for 2 h.
Vacuum distillation gave 0.25 g (73%) of dimethyl
-Formylenamines Ic If were prepared by amina-
tion of corresponding -halo- , -unsaturated al-
dehydes [16, 17]. Synthesis of 2-diethylaminobenzal-
acetophenone Ia was carried out according to the
procedure [18].
3
-oxo-2-(N-piperidyl)butylphosphonate III. bp 107
08 C (1 mm). IR spectrum, , cm : 1715 (C=O). H
1
1
1
3
-Piperidino-3-buten-2-on (Ib). To a solution of
NMR spectrum, , ppm: 1.40 1.50 m (2H, -CH of
2
3
2
.4 g of piperidine in 40 ml of dry THF a solution of
.8 g of 3-bromo-3-buten-2-one in 30 ml of THF was
piperidine), 1.55 1.70 m (4H, -CH of piperidine),
2
1.93 d.d.d (1H, J 20.5, 15.1, 2.8 Hz), 2.32 s (3H,
added with stirring. After keeping the reaction mix-
ture at room temperature for a day obtained piperidine
hydrobromide was filtered off, and solvent was re-
CH CO), 2.35 2.50 m (6H, -CH of piperidine,
3
2
PCH ), 3.75 d (3H, OCH , J 10.0 Hz), 3.76 d (3H,
2
3
1
3
OCH , J 10 Hz). C NMR spectrum, C, ppm:
3
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 12 2001

1
894
RULEV et al.
Found, %: C 65.85, H 10.72, N 7.43. C H NO .
1
8.20 d (CH P, J 140.0 Hz), 24.32, 26.51 ( , -CH ,
2
2
11 21
2
piperidine), 28.57 (CH CO), 50.52 (NCH ), 52.53 d
Calculated, %: C 66.29, H 10.62, N 7.03.
3
2
(
OCH , J 6.4 Hz), 68.63 d (CHN, J 1.6 Hz), 206.59
2
3
1
Methyl 2-morpholinobutanoate (IVc). Yield
32%. IR spectrum, , cm : 1730 (C=O). H NMR
(
C=O). P NMR spectrum
33.21 ppm. Mass spec-
1
1
P
+
trum, m/z (I , %): 262 (M
1) (1), 220 (100).
rel
spectrum, , ppm: 0.87 t (3H, CH , J 7.3 Hz), 1.55
3
Found, %: C 50.06, H 8.24, N 5.57, P 11.76. C H
NO P.Calculated, %: C 50.18, H 8.24, N 5.57, P 11.76.
1
1
22
1
3
.75 m (2H, CH ), 2,45 2.60 m [4H, N(CH ) ],
2 3 2
4
.00 d.d (1H, CHN, J 8.4, 6.6 Hz), 3.60 3.70 m [4H,
1
3
Reaction of -diethylaminobenzalacetophenone
O(CH ) ], 3.65 s (3H, OCH ). C NMR spectrum,
2 2 3
(
Ia) with dimethyl hydrogen phosphite (IIa). To a
, ppm: 10.58 (CH ), 22.11 (CH ), 50.12 (NCH ),
C 3 2 2
mixture of 1.30 g of -diethylaminobenzalacetophe-
none Ia and 0.60 g of dimethyl hydrogen phosphite
placed in a Claisen flask 10 drops of saturated solu-
tion of sodium methylate in methanol was slowly
added and resulting mixture was left for 2 h at room
temperature. Vacuum distillation of it returned 0.90 g
51.05 (OCH ), 67.36 (OCH ), 69.64 (CHN), 172.51
3 2
(C=O). Mass spectrum, m/z (I , %): 187 M (1),
+
rel
128 (100). Found, %: C 57.38, H 9.36, N 7.75.
C H NO . Calculated, %: C 57.73, H 9.15, H 7.48.
9
17
3
Methyl 2-piperidinohexanoate (IVd). Yield 31%.
1
1
IR spectrum, , cm : 1728 (C=O). H NMR spect-
(75%) of starting substrate Ia.
rum, , ppm: 0.85 t (3H, CH , J 7.1 Hz), 1.20
3
Reaction of -formylated enamines Ic If with
1.60 m [12H, (CH ) ,
-piperidine], 2.40 2.55 m
2
3
dialkyl hydrogen phosphite (general procedure).
To a mixture of reagents consisting of 10 mmol of
enamine Ib Ie and 10 mmol of dialkyl hydrogen
phosphite placed in a Claisen flask a saturated solu-
tion of sodium alcoholate in corresponding alcohol
was added dropwise. The mixture was kept for 2 h at
room temperature. Vacuum distillation of it gave a
mixture of compound IVa-e and starting phosphite
II. Purification of esters IVa IVd was carried out
either by preparative chromatography or by consecu-
tive hydrochlorination with dry HCl in ether and
dehydrochlorination with diluted sodium bicarbonate
solution.
(4H, -CH of piperidine), 3.07 d.d (1H, CHN, J 8.8,
6.0 Hz), 3.65 s (3H, OCH3). C NMR spectrum C,
2
1
3
ppm: 14.06 (CH ), 22.70, 24.79, 26.60, 28.67, 29.37
3
(CH ), 50.91 (OCH ), 50.92 (NCH ), 68.66 (CHN),
2
3
2
+
173.23 (C=O). Mass spectrum, m/z (I , %): 213 M
rel
(1), 154 (100). Found, %: C 67.83, H 10.55, N 6.85.
C H NO . Calculated, %: C 67.57, H 10.87, N 6.57.
1
2
23
2
Ethyl 2-diethylamino-3-phenylpropiolate (IVe).
1
1
Yield 30%. IR spectrum, , cm : 1728 (C=O). H
NMR spectrum, , ppm: 1.00 t (6H, CH CH N, J
3
2
7
.1 Hz), 1.14 t (3H, CH CH O, J 7.1 Hz), 2.53 d.q
3 2
(2H, CH CH N, J 13.2, 7,0 Hz), 2.77 d.q (2H,
3 2
CH CH N, J 13.2, 7.1 Hz), 2.87 d.d (1H, CH , J 13.4,
3
2
2
Methyl 2-piperidinobutanoate. Yield 37%. IR
6.2 Hz), 3.05 d.d (1H, CH , J 13.4, 8.6 Hz), 3.60 d.d
2
1
1
spectrum, : 1720 cm . H NMR spectrum, , ppm:
(1H, CHN, J 8.6, 6.2 Hz), 4.05 d.q (2H, CH CH O,
3
2
1
3
0
.87 t (3H, CH , J 7.3 Hz), 1.35 1.60 m (6H, CH ,
J 7.1, 3.8 Hz), 7.15 7.30 m (5H, C H 0). C NMR
3
3
6 5
,
-CH , piperidine), 1.60 1.80 m (2H, CH CH ),
spectrum, , ppm: 13.94 (CH ), 14.39 (CH ), 36.47
C 3 3
2
3
2
2
.40 2.55 m (4H, -CH , piperidine), 3.01 d.d (1H,
(CH ), 44.65 (NCH ), 60.03 (OCH ), 65.17 (CHN),
2
2 2 2
1
3
CHN, J 8.6, 6.2 Hz), 3.66 s (3H, OCH3). C NMR
126.24, 128.22, 129.38, 138.96 (C H ), 172.74 (C=O).
6 5
+
spectrum, , ppm: 10.82 (CH ), 22.62 (CH ), 24.71,
Mass spectrum, m/z (I , %) 249 (1) M , 176 (100),
C
3
2
rel
2
7
6.51 (CH , piperidine), 50.83 (NCH ), 50.91 (OCH ),
158 (61), 130 (27), 91 (33), 56 (34). Found, %: C
71.66, H 9.12, N 5.98. C H NO . Calculated, %: C
2
2
3
0.20 (CHN), 173.04 (C=O). Mass spectrum, m/z
1
5
23
2
+
(I , %): 185 M (1), 126 (100). Found, %: C 65.02,
72.25, H 9.30, N 5.62.
rel
H 10.29, N 7.68. C H NO . Calculated, %: C 64.83,
1
0
19
2
Reaction of -diethylaminocinnamic aldehyde
Ie) with dialkyl hydrogen phosphite (IIa) without
H 10.34, N 7.56.
(
Ethyl 2-piperidinobutanoate (IVb). Yield 35%.
a catalyst. A mixture of 0.20 g of enamine If and
.10 g of dimethyl hydrogen phosphite IIa was left in
1
1
IR spectrum, , cm : 1718 (C=O). H NMR spec-
0
trum, , ppm: 0.90 t (3H, CH , J 7.3 Hz), 1.27 t (3H,
1
3
a sealed ampule at room temperature. 24 h later H
NMR spectrum contained only the signals of starting
substances.
CH CH O, J 7.1 Hz), 1.35 1.60 m (6H, , -CH2-
3
2
piperidine), 1.65 1.85 m (2H, CH CH ), 2.40 2.55 m
3
2
(
6
4H, -CH , piperidine), 3.04 d.d (1H, CHN, J 8.6,
2
1
3
.2 Hz), 4.15 q (2H, CH CH O, J 7.1 Hz). C NMR
Reaction of 1-formyl-1-piperidinopropenoate Ic
with dipropyl hydrogen phosphite (IIc). Reaction was
carried out by the general procedure using the satura-
ted solution of sodium methylate in methanol. Distil-
lation of reaction mixture in a vacuum gave a fraction
3
2
spectrum, , ppm: 10.84 (CH ), 14.63 (CH ), 22.62
C
3
3
(
CH ), 24.71, 26.46 (CH , piperidine), 50.88 (NCH ),
2 2 2
5
9.97 (OCH ), 70.20 (CHN), 172.41 (C=O). Mass
2
+
spectrum, m/z (I , %): 199 M (1), 126 (100).
rel
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 12 2001

CAPTO-DATIVE ACYLENAMINES IN THE REACTIONS
1895
consisting mainly of the starting ester IVa and starting
phosphite IIc.
3. USSR Authors Certificate no. 1728224 (1992);
Izobret., 1992, no. 15, p. 97.
4
. Chruma, J.J., Sames, D., and Polt, R., Tetrahedron
Lett., 1997, vol. 38, no. 29, p. 5085.
Reaction of -diethylaminocinnamic aldehydes
(
Ie) with dimethyl(trimethylsilyl) phosphite (VIII).
a. A mixture of reagents obtained by the addition of
.27 g of dimethyl(trimethylsilyl) phosphite VIII
5. Rulev, A.Yu., Larina, L.I., and Voronkov, M.G.,
0
Tetrahedron Lett., 2000, vol. 41, no. 52, p. 10211.
under argon to 0.30 g of enamine Ie cooled with
liquid nitrogen was kept in a sealed ampule in a
microwave generator (700 W) for 10 min. Distillation
of reaction mixture in a vacuum gave 0.3 g (52%) of
dimethyl 2-diethylamino-3-phenyl-1-trimethylsiloxy-
6. Pudovik, A.N., Zimin, M.G., and Sobanov, A.A., Zh.
Obshch. Khim., 1978, vol. 48, no. 3, p. 487.
7
8
9
. Pudovik, A.N., Zh. Obshch. Khim., 1952, vol. 22,
no. 3, p. 462.
. Pudovik, A.N. and Kitaev, Yu.P., Zh. Obshch. Khim.,
1952, vol. 22, no. 3, p. 467.
1
-propenephosphonate X. bp 120 121 C (1 mm). IR
1
1
spectrum, , cm : 1686 (C=C). H NMR spectrum,
ppm: 0.22 s [9H, (CH ) Si], 0.85 t (6H, CH CH N,
. Nifant’ev, E.E., Khimiya gidrofosforil’nyh soedine-
nii (Chemistry of Hydrophosphoryl Compounds),
Moscow: Nauka, 1983, p. 94.
,
3
3
3
2
J 7.0 Hz), 3.08 q (4H, CH CH N, J 11.0 Hz), 3.71 d
3
2
(
7
0
6H, CH O, J 11.0 Hz), 4.02 s (2H, PhCH ), 7.10
3
2
1
3
.40 m (5H, C H ). C NMR spectrum, C, ppm:
10. Polozov, G.I. and Tishchenko, I.G., Vestnik Belorus.
Gos. Univ., Ser II, 1984, no. 3, p. 3.
6
5
.50 (CH Si), 13.53 (CHd3), 35.40 (PhCH ), 43.69
3
2
(
1
NCH ), 52.07 d (OCH , J 5.8 Hz), 125.94, 128.12,
11. Pudovik, A.N., Gazizov, T.H., and Pashinkin, A.P.,
2
3
3
1
28.88, 139.36 (C H ), 147.70, 148.19 (C=C).
P
Zh. Obshch. Khim., 1970, vol. 40, no. 1, p. 28.
6
5
NMR spectrum,
20.05 ppm. Found, %: C 56.67; H
P
12. Pashinkin, A.P., Gazizov, T.H., and Pudovik, A.N.,
8
.53; N 3.65; P 7.79; Si 7.05. C H NO PSi. Calcu-
18 32 4
Zh. Obshch, Khim., 1970, vol. 40, no. 1, p. 28.
lated, %: C 56.08, H 8.37, N 3.63, P 8.03, Si 7.29.
1
1
3. Arbuzov, B.A. and Tudrii, G.A., Izv. Akad. Nauk
SSSR, Ser. Khim., 1981, no. 2, p. 467.
b. A mixture of reagents obtained by the addition
of 0.18 g of phosphite VIII under argon to 0.20 g of
enamine Ie cooled by liquid nitrogen, was kept in a
sealed ampule for 2 h at 95 C. Vacuum distillation
gave 0.3 g (78%) of dimethyl 2-diethylamino-3-
phenyl-1-trimethylsiloxy-1-propenylphosphonate X.
4. Li, Zhonghua, Zhao, Yongzhen, and Zhang, Jinlin,
J. Cent. China Norm. Univ. Natur. Sci., 1991, vol. 25,
no. 1, p. 62; Ref. Zh. Khim., 1991, 24Zh401.
1
1
5. Trofimov, B.A., D’yachkova, S.G., Nikitina, E.A.,
and Gusarova, N.K., Phosphorus, Sulfur, Silicon Relat.
Elem., 2000, vol. 165, p. 191.
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 12 2001