Stereoselective synthesis of 5,6-disubstituted-3,4-dihydro-1H-pyridin-2-ones, a new class of non-biaryl atropisomeric compounds. Part 1

Article abstract of DOI:10.1016/S0040-4039(02)02583-2

Atropisomeric 5,6-disubstituted-3,4-dihydro-1H-pyridin-2-ones have been synthesized stereoselectively from chiral imines through a Michael reaction and a subsequent stereoselective azacyclization. A thermal study has shown that epimerization of the chiral axis can not take place even at high temperature.

Full text of DOI:10.1016/S0040-4039(02)02583-2

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 44 (2003) 611–614
Stereoselective synthesis of
5,6-disubstituted-3,4-dihydro-1H-pyridin-2-ones, a new class of
non-biaryl atropisomeric compounds. Part 1
Ivan Jabin,* Nicolas Monnier-Benoit, Ste´phane Le Gac and Pierre Netchita¨ılo
URCOM, Universite´ du Havre, Faculte´ des Sciences et Techniques, 25 rue Philippe Lebon, BP 540, 76058 Le Havre Cedex,
France
Received 12 July 2002; revised 6 September 2002; accepted 9 September 2002
Abstract—Atropisomeric 5,6-disubstituted-3,4-dihydro-1H-pyridin-2-ones have been synthesized stereoselectively from chiral
imines through a Michael reaction and a subsequent stereoselective azacyclization. A thermal study has shown that epimerization
of the chiral axis can not take place even at high temperature. © 2002 Elsevier Science Ltd. All rights reserved.
Atropisomerism is a phenomenon which results from
slow rotation about a single bond.1 Enantiomerically
pure atropisomers of axially chiral biaryls have been
widely used as ligands for asymmetric metal-catalyzed
reactions.2 However, their synthesis remains a challenge
and thus non-biaryls atropisomers, i.e. chiral anilides,
1-naphtamides and benzamides, have attracted much
attention in recent literature.3 Applications as chiral
ligands or auxiliaries of these axially chiral amides have
been reported but their usefulness is still limited by the
lack of general methods that can provide them as
enantiomerically pure atropisomers. Indeed, enantiose-
lective syntheses of these chiral amides are rare4 and
they are generally obtained by resolution.5 Conse-
quently, the discover of new classes of easily accessible
atropisomeric compounds which can offer opportuni-
ties for a wide variety of structural changes and espe-
cially for the introduction of chelating groups is of
great interest in asymmetric synthesis.
We recently reported an efficient and expedient method
for the stereoselective synthesis of cyclic enamides
through a tandem process consisting in a Michael reac-
tion of chiral imines, reacting through their tautomeric
enamine form, followed by an aza-cyclization step.6 We
have set out to produce 5,6-disubstituted-3,4-dihydro-
1H-pyridin-2-ones by this route and to study their
ability to generate atropisomerism by restricting rota-
tion of the exocyclic single bond bearing the 6-substitu-
tent (Scheme 1). Indeed, the enamide system being
almost planar, atropisomerism could arise with suitable
bulky substituents on the 6-position by steric or elec-
tronic interactions with the R2 substituent and/or the
substituent borne by the nitrogen. Our aim was to have
the possibility of an easy introduction of chelating
groups on the 6-substituent so we envisaged either
6-aryl or 6-non-aryl substituents. A chiral auxiliary has
been anchored on the starting imine, hoping it will lead
to a stereoselective production of atropisomers under
kinetic control during the aza-cyclization step or under
thermodynamic control by thermal equilibration of the
products. The presence of the chiral auxiliary in the
product should also permit an easy separation of the
atropisomers which are diastereomers and could pre-
vent rotation of the chiral axis by thermodynamic
resistance. An easy removal of R* was required for a
Scheme 1.
* Corresponding author. Tel.: +332 32 74 43 94; fax: +332 32 74 43
91; e-mail: ivan.jabin@univ-lehavre.fr
0040-4039/03/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4039(02)02583-2

612
I. Jabin et al. / Tetrahedron Letters 44 (2003) 611–614
straightforward access to enantiomeric atropisomers.
Thus, optically active 1-phenylethylamine has been cho-
sen as the chiral auxiliary since we already performed
the cleavage of its chiral moiety [i.e. HC*(Me)Ph] on
closely related structures6a,c,f (Scheme 1).
We communicate here our preliminary work concerning
the stereoselective synthesis of the 6-non-aryl-substi-
tuted-3,4-dihydro-1H-pyridin-2-ones, a new class of
atropisomeric compounds, and the study of their
atropisomerism.
Scheme 3.
2-ones 6 and 7 in 26% and 21% overall yields calculated
from starting compounds 1 and 2 (Scheme 4). The
partial degradation of the imines 3 an 4, even during
the Michael reaction-azacyclization sequence (liberation
of phenol), may explained the moderate overall yields
observed. Final products 6 and 7 were in fact obtained
as mixtures of diastereomers (diastereomeric excess of
60 and 64%, respectively15) which were separated by FC
on silica gel and characterized.16
We decided to test the feasibility of our approach with
the diketone 1 and the keto-ester 2, both incorporating
a cyclopropyl moiety.7 Indeed, a quaternary carbon
atom on the a-position of the future imine position was
required in order to prevent formation of the non
desired regioisomeric enamine tautomeric form (a more
stable conjugated enaminone in this case). The starting
chiral imines 3 and 4 were prepared classically8 from
compounds 1 and 2 respectively and optically active
(S)-1-phenylethylamine (Scheme 2).
As expected, the presence of two diastereomers in the
final dihydropyridin-2-ones 6 and 7 is due to the
restricted rotation of the exocyclic single bond bearing
the cyclopropyl substituent. The rotation barrier is
sufficiently high to prevent fast rotation at room tem-
perature since the two different diastereomers of 6 and
7 gave different spectra by 1H NMR analysis. The
absolute configurations of major diastereomers of 6 and
7 have not been determined yet. We presumed the
diastereomeric ratios in the two reactions (i.e. 80:20 and
82:18) arose from asymmetric induction of the chiral
auxiliary during the aza-cyclization step (kinetic ratio)
and not from slow equilibration of the final atropiso-
meric diastereomers (thermodynamic ratio). To prove
this, we therefore heated separately each of the pure
diastereomers (6a, 6b, 7a, and 7b) in refluxing EtOH
and in diglyme up to 150°C. In all cases, no traces of
the other atropisomeric diastereomer was detected by
1H NMR and GC-MS analyses even after prolonged
heating (2 days). These results clearly show that epimer-
ization of the chiral axis by equilibration between
diastereomers a and b can not take place and so we
assume that the observed stereoselectivity corresponds
to the kinetic ratio of the aza-cyclization. The remark-
able high barrier of interconversion between the differ-
ent diastereomers should reflect the steric hindrance
caused by the bulky cyclopropyl moiety. Attempts to
improve the stereoselectivity by conducting the reaction
at lower temperatures failed since similar de were
observed at 0°C and the reaction became excessively
slow at −20°C.
Imines 3 and 4 revealed to be unstable under acidic
conditions, either during the course of the reaction
(presence of TFA), in CHCl3 or on silica gel. Indeed, in
1
both cases GC-MS, H NMR and TLC analyses of the
crude reaction mixtures have shown the formation of
traces of their respective degradation product. More-
over, an attempt of purification of imine 3 by flash
chromatography (FC) on silica gel led, besides the
expected imine 39 (42% yield), to the same by-product
in higher amount. This unexpected degradation com-
pound has been isolated and its 1H NMR and MS
spectra were consistent with the pyrrolic structure 5.10
The origin of this latter can be tentatively rationalized
by a cyclopropyl rearrangement initiated by the forma-
tion of the iminium ion of 3. The resulting dihydro-
pyrrole should aromatize upon air oxidization giving
the more stable pyrrole 5 (Scheme 3). A careful litera-
ture survey has shown that such an acid-catalyzed
rearrangement of a-cyclopropyl imines has already
been reported but no explanations concerning the
mechanism have been given.11
The low stability of imines 3 and 4 prompted us to use
the crude compounds in the following step. Phenyl
acrylate12 was chosen as the Michael acceptor since this
highly electrophilic olefin is known to lead in situ to
6-ring enamides by loss of a molecule of phenol.13
Thus, reaction14 of crude imines 3 and 4 with phenyl
acrylate gave respectively the expected dihydropyridin-
Scheme 2.
Scheme 4.

I. Jabin et al. / Tetrahedron Letters 44 (2003) 611–614
613
Given that the presence of the cyclopropyl group led to
moderate yields at each step of the process, we envis-
aged to replace it by more stable substituents. Thus, a
second set of experiments with starting keto-esters 817
and 918 was carried out. Their corresponding crude
chiral imines 10 and 11 were obtained under drastic
conditions since prolonged heating times (7 d. and 10 d.
respectively) were needed to achieve a total conversion
of the starting keto-esters. The severe steric hindrance
caused by the gem-dimethyl or cyclopentyl groups, in
comparison of the one caused by the cyclopropyl
group, is surely responsible of the low reactivity of the
carbonyl group. Imines 10 and 11 were first reacted
with phenyl acrylate at room temperature. However, no
Michael reaction took place at this temperature. Care-
ful monitoring of the reaction by GC-MS analyses of
the reaction mixture has shown that a minimum tem-
perature of 60°C is required for the Michael reaction
but that the subsequent aza-cyclization can not occur
even at drastic temperatures (180°C) (Scheme 5).
efficient Michael reaction-azacyclization sequence.
However, this preliminary study on 6-non-aryl com-
pounds has also shown that the choice of the 6-exo-sub-
stituent which generates the atropisomerism is limited.
Thus, we focused our interest on 6-aryl dihydropyridi-
nones which revealed to be more versatile and the study
concerning their synthesis will be published in an
accompanying paper.
Acknowledgements
We thank the Laboratoire de Spectrome´trie de Masse,
(Universite´ de Rouen, Faculte´ des Sciences, IRCOF,
France) for the HMRS analyses.
References
1. Eliel, E. L.; Wilen, S. H.; Mander, L. N. Stereochemistry
of Organic Compounds; John Wiley and Sons: New York,
1994; pp. 1142–1155.
2. Noyori, R. Asymmetric Catalysis in Organic Synthesis;
Wiley: New York, 1994.
This unexpected result can be rationalized if we con-
sider that during the aza-cyclization step the bulky
gem-dimethyl or cyclopentyl groups should push away
the chiral auxiliary moiety, this latter preventing the
approach of the ester chain (Fig. 1).
3. For a review see: (a) Clayden, J. Angew. Chem., Int. Ed.
Engl. 1997, 9, 949–951. For recent leading references on
axially chiral anilides see: (b) Ates, A.; Curran, D. P. J.
Am. Chem. Soc. 2001, 123, 5130–5131; (c) Fujita, M.;
Kitagawa, O.; Yamada, Y.; Izawa, H.; Hasegawa, H.;
Tagushi, T. J. Org. Chem. 2000, 65, 1108–1114; (d)
Clayden, J.; Johnson, P.; Pink, J. H.; Helliwell, M. J.
Org. Chem. 2000, 65, 7033–7040; (e) Hugues, A. D.;
Price, D. A.; Shishkin, O.; Simpkins, N. S. Tetrahedron
Lett. 1996, 37, 7607–7610. Axially chiral 1-naphtamides:
(f) Dai, W.-M.; Yeung, K. K. Y.; Chow, C. W.; Williams,
I. D. Tetrahedron: Asymmetry 2001, 12, 1603–1613; (g)
Clayden, J.; Lai, L. W. Tetrahedron Lett. 2001, 42, 3163–
3166; (h) Clayden, J.; Helliwell, M.; McCarty, C.; West-
lund, N. J. Chem. Soc., Perkin Trans. 1 2000, 3232–3249;
(i) Thayumanavan, S.; Beak, P.; Curran, D. P. Tetra-
hedron Lett. 1996, 37, 2899–2902. Axially chiral benz-
amides: (j) Clayden, J.; Lai, L. W.; Helliwell, M. Tetra-
hedron: Asymmetry 2001, 12, 695–698; (k) Clayden, J.;
Pink, J. H.; Samreen, A. Y. Tetrahedron Lett. 1998, 39,
105–108. See also for atropisomeric pyrazinones: (l)
Tulinsky, J.; Cheney, B. V.; Mizsak, S. A.; Watt, W.;
Han, F.; Dolak, L. A.; Judge, T.; Gammill, R. B. J. Org.
Chem. 1999, 64, 93–100.
In conclusion, we have succeeded in the stereoselective
synthesis of atropisomeric dihydropyridinones and we
have shown that epimerization of the chiral axis can
not take place at standard temperatures proving that
the observed stereoselectivity is under kinetic control.
Moreover, the route developed for the preparation of
this new class of atropisomeric compounds relies on an
4. See Refs 3a,c. Koide, H.; Uemura, M. Chem. Commun.
1998, 2483.
5. See Refs 3a,e,f,g. (a) Chen, Y.; Smith, M. D.; Shimizu, K.
D. Tetrahedron Lett. 2001, 42, 7185–7187; (b) Clayden,
J.; McCarthy, C.; Cumming, J. G. Tetrahedron Lett.
2000, 41, 3279–3283.
Scheme 5.
6. (a) Jabin, I.; Revial, G.; Tomas, A.; Lemoine, P.; Pfau,
M. Tetrahedron: Asymmetry 1995, 6, 1795–1812; (b)
Jabin, I.; Revial, G.; Pfau, M.; Decroix B.; Netchita¨ılo, P.
Org. Lett. 1999, 1, 1901–1904; (c) Revial, G.; Jabin, I.;
Pfau, M. Tetrahedron: Asymmetry 2000, 11, 4975–4983;
(d) Jabin, I.; Revial, G.; Monnier-Benoit, N.; Netchita¨ılo,
P. J. Org. Chem. 2001, 66, 256–261; (e) Jabin, I.; Netchi-
ta¨ılo, P. Tetrahedron Lett. 2001, 42, 7823–7827; (f)
Figure 1.

614
I. Jabin et al. / Tetrahedron Letters 44 (2003) 611–614
Revial, G.; Jabin, I.; Redolfi, M.; Pfau, M. Tetrahedron:
found 311.1884 (M+, HRMS). Minor diastereomer: oil,
[h]2D0=−321.6 (c 1.03, EtOH). EIMS m/z (rel int) 311
(M+, 17), 254 (19), 151 (25), 105 (base), 79 (15). IR (film):
Asymmetry 2001, 12, 1683–1688; (g) Jabin, I.; Revial, G.;
Pfau, M.; Netchita¨ılo, P. Tetrahedron: Asymmetry 2002,
13, 563–567. See also: Benovsky, P.; Stephenson, G. A.;
Stille, J. R. J. Am. Chem. Soc. 1998, 120, 2493–2500;
d’Angelo, J.; Cave´, C.; Desmae¨le, D. Israel Journal of
Chemistry 1997, 37, 81–85.
1755, 1704, 1556 cm−1 1H NMR (200 MHz, CDCl3) l
.
1.03 (t, J=7.4 Hz, 3H), 1.58–2.24 (m, 4H), 1.63 (d,
J=6.3 Hz, 3H), 1.98 (s, 3H), 2.29–2.55 (m, 3H), 2.69 (dq,
J1=7.4 Hz, J2=18.8 Hz, 1H), 3.07 (dd, J1:J2:10 Hz,
1H), 3.20 (ddd, J1=6.3 Hz, J2:J3:11 Hz, 1H), 5.75 (q,
7. Pure diketone 1 and keto-ester 2 were obtained after FC
(EtOAc, cyclohexane) from 3,5-heptanedione and 3-oxo-
pentanoic acid methyl ester in 42 and 54% yields, respec-
tively. Reaction conditions: 1,2-dibromoethane (1 equiv.),
K2CO3 (3 equiv.), refluxing acetone, 4–6 days.
1
J=7.0 Hz, 1H), 7.18-7.43 (m, 5H). H NMR (200 MHz,
CDCl3) l 8.04, 10.36, 17.84, 31.75, 32.88, 33.48, 33.96,
45.79, 54.04, 62.22, 102.6, 126.2 (2C), 127.7, 128.9 (2C),
141.2, 163.6, 195.5, 205.8. Mol. mass calcd. 311.1885;
found 311.1882 (M+, HRMS).
1: see Zefirov, N. S.; Kozhushkov, S. I.; Kuznetsova, T.
S.; Gleiter, R.; Eckert-Maksic, M. J. Org. Chem. USSR
1986, 95–105.
7: major diastereomer: oil, [h]2D0=−64.8 (C 0.26, EtOH).
EIMS m/z (rel int) 313 (M+., 40), 226 (10), 209 (17), 181
(15), 150 (11), 105 (base), 79 (15). IR (film): 1731, 1556
2: colorless oil, EIMS m/z (rel int) 156 (M+., 8), 141 (16),
127 (base), 125 (17), 95 (23), 79 (20), 59 (44), 57 (42). IR
1
cm−1. H NMR (200 MHz, CDCl3) l 1.65 (d, J=6.3 Hz,
(film): 1747–1670 cm−1 1H NMR (200 MHz, CDCl3) l
.
3H), 1.72–1.88 (m, 2H), 2.07 (s, 3H), 2.19 (dd, J1=5.5
Hz, J2=12.5 Hz, 1H), 2.29–2.47 (m, 3H), 2,83 (ddd,
J1=6.2 Hz, J2:J3:11 Hz, 1H), 3.24 (dd, J1=8.2 Hz,
J2=11 Hz, 1H), 3.49 (s, 3H), 5.69 (q, 7.0 Hz, 1H),
7.18-7.4 (m, 5H). 13C NMR (50 MHz, CDCl3) l 11.03,
17.64, 31.53, 33.99, 34.05, 45.66, 52.63, 54.41, 56.48,
102.4, 127.9 (2C), 128.0, 128.7 (2C), 139.6, 162.5, 173.4,
196.8. Mol. mass calcd. 313.1678; found 313.1675 (M+,
HRMS). Minor diastereomer: oil, [h]2D0=−368.4 (c 1.28,
EtOH). EIMS m/z (rel int) 313 (M+, 40), 254 (6), 226
(10), 209 (17), 181 (15), 150 (11), 105 (base), 79 (15). IR
1.00 (t, J=7.0 Hz, 3H), 1.38 (s, 4H), 3.80 (q, J=7.0 Hz,
2H), 3.67 (s, 3H). 13C NMR (50 MHz, CDCl3) l 8.60,
19.05 (2C), 34.71, 35.47, 52.56, 171.9, 206.2.
8. Reaction conditions: azeotropic removal of water by
refluxing in toluene in a Dean–Stark apparatus, catalytic
amount of TFA, 48 h.
9. 3: oil, [h]2D0=−33.5 (c 0.92, EtOH). EIMS m/z (rel int)
257 (M+, 26), 228 (11), 124 (67), 105 (base), 79 (19). IR
1
(CHCl3): 1603 cm−1. H NMR (200 MHz, CDCl3) l 1.05
(t, J=7.4 Hz, 3H), 1.15 (t, J=7.4 Hz, 3H), 1.55 (d,
J=7.0 Hz, 3H), 2.28 (q, J=7.0 Hz, 2H), 2.63–2.89 (m,
3H), 2.92–3.23 (m, 2H), 3.43 (ddd, J1=J2=J3=10.4 Hz,
1H), 4.92 (q, J=7.0 Hz, 1H), 7.15–7.42 (m, 5H). 13C
NMR (50 MHz, CDCl3) l 8.88, 12.83, 17.75, 19.66,
27.20, 33.95, 45.49, 52.09, 105.2, 126.9 (2C), 127.7, 129.0
(2C), 140.9, 166.6, 181.9, 194.9.
1
(film): 1731 cm−1. H NMR (200 MHz, CDCl3) l 1.58 (d,
J=7.0 Hz, 3H), 1.71–1.91 (m, 2H), 1.94 (s, 3H), 2.23 (dd,
J1=5.5 Hz, J2=12.5 Hz, 1H), 2.31–2.42 (m, 2H), 2.50
(ddd, J1=2.3 Hz, J2=4.7 Hz, J3=12.5 Hz, 1H), 3.01 (dd,
J1=8.2 Hz, J2=10.1 Hz, 1H), 3.36 (ddd, J1=5.5 Hz,
J2:J3:11 Hz, 1H), 3.71 (s, 3H), 5.68 (q, J=6.8 Hz,
1H), 7.15–7.42 (m, 5H). 13C NMR (50 MHz, CDCl3) l
10.69, 17.36, 31.42, 34.04, 34.16, 46.09, 52.95, 54.37,
56.56, 102.8, 126.7 (2C), 127.8, 129.1 (2C), 141.3, 162.8,
173.6, 196.5. Mol. mass calcd. 313.1678; found 313.1675
(M+, HRMS).
10. 5: EIMS m/z (rel int) 255 (M+, 28), 226 (26), 122 (77), 105
1
(base). H NMR (200 MHz, CDCl3) l 1.04 (t, J=7.0 Hz,
3H), 1.13 (t, J=7.0 Hz, 3H), 1.80 (d, J=7.0 Hz, 3H),
2.79 (q, J=7.0 Hz, 2H), 2.87-2.94 (m, 2H), 5.39 (q,
J=7.0 Hz, 1H), 6.55 (d, J=3.1 Hz, 1H), 6.60 (d, J=3.1
Hz, 1H), 6.93-7.37 (m, 5H).
11. (a) Celerier, J. P.; Haddad, M.; Jacoby, D.; Lhommet, G.
Tetrahedron Lett. 1987, 28, 6597–6600; (b) Grotjahn, D.
B.; Volhart, K. P. C. Synthesis 1993, 579–605.
12. Phenyl acrylate was prepared according to the literature:
Ahlbretch, A.; Codding, D. W. J. Am. Chem. Soc. 1953,
75, 984.
13. See Refs 6b,e,g.
14. Reactions conditions: phenyl acrylate (1–2 equiv.), neat,
room temperature, 48 h.
17. Pure keto-ester 8 was obtained from 3-oxo-pentanoic acid
methyl ester after FC (EtOAc, cyclohexane) in 47% yield.
Reaction conditions: MeONa (3 equiv.), MeI (2.7 equiv.),
MeOH, rt, 2 days.
8: colorless oil, EIMS m/z (rel int) 158 (M+, 1), 127 (7),
102 (54), 87 (22), 73 (18), 70 (27), 57 (base). IR (CHCl3):
1
1754–1701 cm−1. H NMR (200 MHz, CDCl3) l 0.92 (t,
J=7.0 Hz, 3H), 1.23 (s, 4H), 2.35 (q, J=7.0 Hz, 2H),
3.59 (s, 3H). 13C NMR (50 MHz, CDCl3) l 8.23, 22.14
(2C), 31.26, 52.51, 55.50, 174.4, 208.8.
15. The de were determined by a GC-MS analysis of the
1
crude reaction mixtures and were confirmed by H NMR
18. Pure keto-ester 9 was prepared from 3-oxo-pentanoic
acid methyl ester after FC (EtOAc, cyclohexane) in 84%
yield. Reaction conditions: 1,4-diiodobutane (1.2 equiv.),
K2CO3 (5 equiv.), DMSO, rt, 24 h.
analyses.
16. 6: major diastereomer: oil, [h]2D0=−169.2 (c 0.92, EtOH).
EIMS m/z (rel int) 311 (M+, 30), 254 (26), 151 (36), 105
1
(base), 79 (23). IR (film): 1713, 1556 cm−1. H NMR (200
9: colorless oil, EIMS m/z (rel int) 184 (M+, 1), 128
(base), 96 (23), 87 (28), 67 (42), 57 (99). IR (CHCl3):
MHz, CDCl3) l 0.84 (t, J=7.0 Hz, 3H), 1.59–2.21 (m,
5H), 1.65 (d, J=7.0 Hz, 3H), 2.15 (s, 3H), 2.26–2.77 (m,
4H), 3.25 (dd, J1=9.0 Hz, J2=10.6 Hz, 1H), 5.77 (q,
J=7.0 Hz, 1H), 7.20–7.43 (m, 5H). 13C NMR (50 MHz,
CDCl3) l 7.77, 10.86, 17.46, 31.95, 33.36, 33.71, 33.93,
45.59, 54.47, 62.25, 102.4, 127.7 (2C), 128.1, 128.7 (2C),
138.9, 162.9, 195.8, 205.8. Mol. mass calcd. 311.1885;
1
1748–1700 cm−1. H NMR (200 MHz, CDCl3) l 0.98 (t,
J=7.0 Hz, 3H), 1.44–1.68 (m, 4H), 1.96–2.11 (m, 4H),
2.36 (q, J=7.0 Hz, 2H), 3.64 (s, 3H). 13C NMR (50
MHz, CDCl3) l 8.60, 25.83 (2C), 32.27, 33.34 (2C),
52.68, 66.70, 174.4, 207.1.