Reactions of methoxycarbonylcarbene with 3-ethyl-2-phenyl- and 2,3-diphenyloxazolidines

Article abstract of DOI:10.1023/A:1015057519648

The reactions of methoxycarbonylcarbene, which was generated by catalytic thermal decomposition of methyl diazoacetate, with 3-ethyl-2-phenyl- or 2,3-diphenyloxazolidines resulted in the insertion of the former predominantly at the C - N bond of the oxazo

Full text of DOI:10.1023/A:1015057519648

2144
Russian Chemical Bulletin, International Edition, Vol. 50, No. 11, pp. 2144—2148, November, 2001
Reactions of methoxycarbonylcarbene with 3-ethyl-2-phenyl-
and 2,3-diphenyloxazolidines
A. P. Molchanov,a A. V. Stepakov,a J. Kopf,b I. G. Zenkevich,a and R. R. Kostikova«
aSt. Petersburg State University,
2 Universitetsky prosp., 198504 St. Petersburg, Russian Federation.
E-mail: rkost@rk1198.spb.edu
bInstitute of Inorganic Chemistry,
6 Martin Luther King Platz, D-20146 Hamburg, Germany.*
E-mail: kopf@xray.chemie.uni-hamburg.de
The reactions of methoxycarbonylcarbene, which was generated by catalytic thermal
decomposition of methyl diazoacetate, with 3-ethyl-2-phenyl- or 2,3-diphenyloxazolidines
resulted in the insertion of the former predominantly at the C—N bond of the oxazolidine
ring to produce substituted esters of morpholine-3-carboxylic acid.
Key words: carbenes, diazo compounds, oxazolidines, insertion reactions.
Previously,1,2 it has been noted that the reactions of
ethoxycarbonylcarbene with 2-substituted 1,3-dioxolanes
resulted in the insertion of the carbene at the C—O
bond of the dioxolane to form esters of 3-substituted
1,4-dioxane-2-carboxylic acids.
Scheme 1
–
MeO2CCH
MeO2C
Ph
N
+N
Ph
O
In the present study, we established that the reaction
of methoxycarbonylcarbene, which was generated by
catalytic thermal decomposition of methyl diazoacetate,
(120 °C, copper bronze), with 3-ethyl-2-phenyl-
oxazolidine (1à) afforded a complex mixture of prod-
ucts. According to the GLC data, this mixture contained
dimethyl maleate, dimethyl fumarate, methyl cinnamate,
methyl 4-ethyl-2-phenylmorpholine-3-carboxylate (2),
methyl 4-ethyl-3-phenylmorpholine-2-carboxylate (3),
and dimethyl 4-ethyl-7-phenyl-1,4-oxazepane-5,6-
dicarboxylate (4) (Scheme 1). The ratio of esters 2, 3,
and 4 in the resulting reaction mixture depended on the
ratio of the starting reagents (diazo ester : oxazolidine).
The ratio of the esters changed from 3 : 1 : 0.3 to
0.6 : 1 : 1.3 as the above-mentioned ratio of the reagents
was increased from 0.7 : 1 to 1.8 : 1. This result agrees
with the fact that ester 4 was generated from ester 2. It
should be noted that attempts to obtain products of the
insertion of carbene at the C—N or C—O bond with the
use of other catalysts for decomposition of diazoacetate
(Rh2(OAc)4, benzene, 80 °C; Pd(OAc)2, CH2Cl2,
ca. 20 °C; or CuSO4, benzene, 80 °C) failed.
O
N
5
2
N2CHCO2Me
Ph
Cu, 120 °C
O
Ph
N
O
3
N
Ph
1a
+O
MeO2C
MeO2CCH
–
6
–
MeO2CH
MeO2C
N
MeO2C
+N
:CHCO2Me
MeO2C
2
Ph
O
O
Ph
7
4
isomers 2 and 3 was made based on the correlation
between the order in which chromatographic elution of
the isomers occurred and their intramolecular dynamic
parameters Ådyn (the sums of the vibrational and rota-
tional energies).3 The higher energy Ådyn for ester 3
(78.2±1.8 kcal mol–1) compared to that for ester 2
(76.3±1.5 kcal mol–1) corresponds to the lower Ir value
(1711±2 and 1736±2, respectively). The 1H NMR spec-
trum of a mixture of compounds 2 and 3 has doublet
signals (δ 4.19 and 4.98; δ 4.31 and 4.79, respectively;
J = 7 Hz for all siganls) belonging to the methine
The reaction mixture was separated by column chro-
matography. After chromatography, an inseparable mix-
ture of monoesters 2 and 3 was obtained. The structures
of these esters were confirmed by the mass spectra and
the chromatographic retention indices (Ir) on a standard
nonpolar phase. In the latter case, the assignment of
* Institut für anorganische Chemie, 6 Martin Luther King
Platz, D-20146 Hamburg, Germany.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2048—2051, November, 2001.
1066-5285/01/5011-2144 $25.00 © 2001 Plenum Publishing Corporation

Reactions of methoxycarbonylcarbene
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 11, November, 2001 2145
Table 1. Selected bond lengths (d) in compound 4
Table 3. Selected dihedral angles (α) in
compound 4
Bond
d/Å
Bond
d/Å
Angle
α/deg
O(1)—C(7)
O(1)—C(2)
1.417(9)
1.436(5)
1.204(9)
1.332(6)
1.453(8)
1.341(9)
1.443(7)
C(71)—C(76) 1.391(10)
C(72)—C(73)
C(41)—C(42)
C(74)—C(75)
C(75)—C(76)
C(5)—C(51)
C(6)—C(61)
1.389(3)
1.516(8)
1.390(6)
1.387(3)
1.534(8)
1.520(8)
1.553(10)
1.518(2)
O(1)—C(2)—C(3)—N(4)
C(3)—N(4)—C(5)—C(6)
N(4)—C(5)—C(6)—C(7)
N(4)—C(5)—C(6)—C(61)
–65.8(2)
–79.8(1)
77.9(1)
O(51)—C(51)
O(52)—C(51)
O(52)—C(52)
O(62)—C(61)
O(62)—C(62)
N(4)—C(3)
N(4)—C(5)
N(4)—C(41)
C(2)—C(3)
C(71)—C(72)
–47.4(1)
N(4)—C(5)—C(51)—O(52) –167.5(1)
C(5)—C(6)—C(7)—O(1)
C(5)—C(6)—C(7)—C(71)
C(6)—C(7)—O(1)—C(2)
C(7)—O(1)—C(2)—C(3)
C(41)—N(4)—C(5)—C(51)
C(51)—C(5)—C(6)—C(61)
C(52)—O(52)—C(51)—C(5)
–13.8(2)
108.8(1)
–66.0(1)
99.0(1)
–78.1(1)
–179.0(1)
179.4(1)
1.462(10) C(6)—C(7)
1.462(8) C(7)—C(71)
1.476(10) C(73)—C(74) 1.383(10)
1.513(10) C(5)—C(6)
1.390(5) O(61)—C(61)
1.553(13)
1.207(3)
O(52)—C(51)—C(5)—N(4) –167.5(1)
protons at the C(2) and C(3) atoms of esters 2 and 3,
respectively. The spin-spin coupling constants are in-
dicative of the trans arrangement of the substituents at
the adjacent C atoms.
C(61)—C(6)—C(7)—C(71)
C(62)—O(62)—C(61)—O(61)
C(72)—C(71)—C(7)—C(6)
–128.0(1)
–4.6(2)
–122.4(1)
Diester 4 was isolated in the individual state in
30% yields (Ir = 2077±3). Its composition and structure
were established based on the results of elemental analysis,
spectral data, and X-ray diffraction analysis (Tables 1—3).
The 1H NMR spectrum of diester 4 has doublet signals
for the methine protons at the C(5) and C(7) atoms and
a triplet signal for the methine H(6) proton (δ 4.16, 5.17,
and 3.59, respectively; J = 7 Hz for all signals). The
spin-spin coupling constants are indicative of the trans
arrangement of the substituents at the adjacent C atoms.
The assignments of the signals for the protons at the
C(5) and C(7) atoms in compound 4 (as well as for
analogous protons in substituted morpholines) were made
based on comparison with the results of calculations
using additive schemes4 according to which the protons
at the C(5) and C(7) atoms should give signals at δ ca. 4
and ca. 5, respectively. In all cases, only the relative
configurations of the substituents in the ring were estab-
lished. The structure of diester 4 was additionally con-
firmed by X-ray diffraction analysis (Fig. 1).
Hydrolysis of a fraction containing monoesters 2 and
3 in the presence of HCl afforded hydrochloride
of 4-ethyl-2-phenylmorpholine-3-carboxylic acid (8)
(Scheme 2). The composition and the structure of acid 8
were established based on the results of elemental analy-
sis and spectral data. The 1H NMR spectrum of 8 has a
signal for the proton of the COOH group (δ 12.22),
doublet signals for the methine protons at the C(2) and
C(3) atoms (δ 4.65 and 4.18, respectively; J = 10 Hz for
both signals), and signals for the protons of the methyl-
ene and ethyl groups and the aromatic fragment.
Table 2. Selected bond angles (ω)
in compound 4
Angle
ω/deg
C(7)—O(1)—C(2)
113.57(11)
C(51)—O(52)—C(52) 115.32(12)
C(61)—O(62)—C(62) 115.41(11)
C(3)—N(4)—C(5)
C(61)—C(6)—C(5)
C(5)—N(4)—C(41)
O(1)—C(2)—C(3)
115.58(11)
107.37(11)
113.30(12)
111.55(12)
O(61)—C(61)—O(62) 123.25(13)
C(61)—C(6)—C(7)
C(7)—C(6)—C(5)
C(3)—N(4)—C(41)
O(61)—C(61)—C(6)
O(62)—C(61)—C(6)
N(4)—C(3)—C(2)
N(4)—C(41)—C(42)
O(1)—C(7)—C(6)
O(1)—C(7)—C(71)
C(71)—C(7)—C(6)
111.90(11)
115.03(11)
110.87(11)
126.25(13)
110.49(11)
110.49(11)
113.23(13)
112.13(11)
108.38(11)
112.72(12)
C(72)—C(71)—C(76) 119.00(13)
C(72)—C(71)—C(7)
C(76)—C(71)—C(7)
121.54(13)
119.46(13)
C(73)—C(72)—C(71) 120.14(14)
N(4)—C(5)—C(51)
N(4)—C(5)—C(6)
114.78(12)
112.35(11)
C(72)—C(73)—H(73) 119.60(16)
C(73)—C(74)—C(75) 119.18(15)
C(74)—C(73)—C(72) 120.82(15)
Scheme 2
C(51)—C(5)—C(6)
O(51)—C(51)—O(52) 123.91(14)
O(51)—C(51)—C(5) 124.29(13)
C(76)—C(75)—C(74) 120.18(15)
C(75)—C(76)—C(71) 120.67(14)
113.18(11)
HO2C
Ph
N
HCl
2 + 3
•HCl
O
O(52)—C(51)—C(5)
111.69(12)
8

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Russ.Chem.Bull., Int.Ed., Vol. 50, No. 11, November, 2001
Molchanov et al.
spectrum of ester 9 has doublet signals for the methine
protons at the C(2) and C(3) atoms (δ 5.03 and 4.32,
respectively; J = 6 Hz for both signals).
C(74)
C(75)
C(73)
C(72)
Scheme 4
–
Ph
Ph
C(52)
MeO2CCH
C(76)
Ph
MeO2C
Ph
N
+N
N
N2CHCO2Me
C(71)
C(7)
Ph
Ph
O(52)
O(1)
Cu, 120 °C
O
O
O
C(51)
1b
10
9
O(51)
Hence, the results obtained in the present study
provide evidence that methoxycarbonylcarbene reacted
with oxazolidines 1a,b to form N-ylide 5, N-ylide 10, or
O-ylide 6, which underwent the Stevens rearrangement
with the ring expansion to produce morpholine deriva-
tives. The results of quantum-chemical MNDO/1 cal-
culations for ylides 5 and 6 confirmed that the formation
of N-ylide 5 is thermodynamically more favorable com-
pared to O-ylide 6 (by 3—5 kcal mol–1). The subsequent
reaction of ester 2 with methoxycarbonylcarbene also
afforded N-ylide 7, which was rearranged into diester 4.
C(2)
C(6)
C(5)
C(61)
C(3)
N(4)
C(41)
O(61)
O(62)
C(62)
C(42)
Fig. 1. Overall view of molecule 4 according to the results of
X-ray diffraction study.
Experimental
The IR spectra were recorded on a UR-20 spectrophotom-
eter (2% solutions in CHCl3 for compounds 4 and 9; a KBr
pellet for compound 8). The 1H NMR spectra were measured
on a Bruker AM-300 instrument (300 MHz). The resulting
compounds were tested for purity and the reaction mixtures
were analyzed by TLC on Silufol UV-254 plates and by GLC
on a Tsvet-126 chromatograph equipped with a flame ioniza-
tion detector (nitrogen as the carrier gas; a 1500½3-mm glass
column; 5% SE-30 on Chromaton N-AW as the stationary
The spin-spin coupling constants for the protons at
the C(2) and C(3) atoms are indicative of their trans
arrangement. In addition, hydrochloride salt 8 was con-
verted into free amino acid and was subjected to esterifi-
cation with diazomethane. The reaction of the resulting
ester with methoxycarbonylcarbene afforded ester whose
spectral data are identical with those of diester 4 isolated
previously (Scheme 3).
phase). The retention indices (Ir) were determined on
a
Biokhrom-1 chromatograph equipped with a flame ionization
detector and a quartz capillary column (25 m ½ 0.20 mm) with
the OV-101 phase (4300 t.p. m–1; t.p. are theoretical plates) in
the temperature-programming mode from 60 to 240 °C at a
rate of 6 deg min–1. To determine the indices Ir, a sample
(0.6 µL) was dosed together with a mixture of the reference
C6—C18 n-alkanes. The parameters of the chromatographic
peaks were recorded using a TR 2213 integrator. The linear-
logarithmic Ir indices were calculated on a programmed CASIO
PB100 microcalculator using a program available in the manual.5
The mass spectra of the products obtained in the reaction
of 3-ethyl-2-phenyloxazolidine with methoxycarbonylcarbene
were measured on an LKB-2091 GLC-mass spectrometer
equipped with a glass packed column (3 m ½ 2 mm; 3 % SE-30
on Chromaton-W-HMDS) in the temperature-programming
mode from 60 to 250 °C at a rate of 6 deg min–1. The energy
of ionizing electrons was 70 eV, the current of emission was
25 µA, the accelerating voltage was 3.5 kV, and the tempera-
ture of the ion source was 280 °C.
Scheme 3
1) Na2CO3
MeO2C
2) CH2N2
3) N2CHCO2Me
N
HO2C
Ph
N
MeO2C
•HCl
O
O
Ph
8
4
The reaction of 2,3-diphenyloxazolidine (1b) with
methoxycarbonylcarbene, which was generated under
the same conditions, was accompanied by substantial
resinification of the reaction mixture. Column chroma-
tography of this mixture made it possible to isolate only
methyl 2,4-diphenylmorpholine-3-carboxylate (9) in
13% yield (Scheme 4). The composition and the struc-
ture of ester 9 were established based on the results of
elemental analysis and spectral data. The 1H NMR
The intramolecular energies were calculated by molecular
dynamics using the HyperChem 5.1 program package with the
following parameters for simulation: the temperature was 300 Ê,
the energy was averaged with a step of 0.0005 ps, the relax-

Reactions of methoxycarbonylcarbene
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 11, November, 2001 2147
ation time was 0.1 ps, the total time of simulation (no larger
than 20 ps) was chosen depending on the rate of the attain-
ment of the reasonable accuracy (∼2%) of the estimation of the
Edyn parameters. The initial period of simulation, which was
equivalent to heating of the molecule to a given temperature
(∼1.5 ps), was excluded and calculations were resumed using
the command RESTART. The molecular geometry was ini-
tially optimized using the MM+ and AM1 methods (simulta-
neously, the relative thermodynamical stabilities of the isomers
were estimated).
fraction (0.14 g) containing a mixture of monoesters 2 and 3.
The mixture was kept at ca. 20 °C for 48 h. Water was removed
by azeotropic distillation with benzene. Then dry ether (8 mL)
and several drops of MeOH were added to the residue until
crystallization started. The crystalline precipitate was filtered
off and washed with ether. Salt 8 was obtained in a yield of
47 mg (6%), m.p. 234—236 °C (decomp.). Found (%): C, 57.18;
H, 6.72; N, 5.11. C13H18ClNO3. Calculated (%): C, 57.46;
H, 6.68; N, 5.15. IR, ν/cm–1: 3240 (N—H), 2960, 2680, 1750
(C=O), 1610, 1490, 1460, 1370, 1250, 1130, 1070, 1010, 980,
950. 1H NMR (DMSO-d6), δ: 1.14 (t, 3 H, Me, J = 7 Hz);
2.85 (m, 2 H, CH2); 3.35 and 3.61 (both m, 1 H each,
NCH2); 4.18 (d, 1 H, H(3), J = 10 Hz); 4.44 (m, 2 H,
OCH2); 4.65 (d, 1 H, H(2), J = 10 Hz); 7.46—7.81 (m, 5 H,
Ar); 12.22 and 13.20 (both br.s, 1 H each, NH, OH).
Diester 4 from salt 8. A 1% Na2CO3 solution was added
dropwise to a solution of salt 8 (30 mg, 0.1 mmol) in water
(1.5 mL) until a white amorphous precipitate formed. The
precipitate was extracted with ether. The extract was dried with
MgSO4, ether was evaporated to the volume of ca. 2 mL, and
an ethereal solution of diazomethane was added dropwise until
liberation of nitrogen ceased and the solution turned pale-
yellow. The solvent was evaporated at ca. 20 °C and then
octane (3 mL) and copper bronze (10 mg) were added to the
residue. The reaction mixture was heated to 120 °C and methyl
diazoacetate was slowly added until the initial compound was
consumed (TLC control). The mixture was cooled, the solvent
was distilled off in vacuo, and the residue was separated on a
column with silica gel using a 1 : 1 hexane—Et2O mixture as
the eluent. Diester 4 was isolated in a yield of 5.8 mg (16%).
Its NMR spectral data were identical with those of the speci-
men obtained previously.
Methyl trans-2,4-diphenylmorpholine-3-carboxylate (9).
Methyl diazoacetate (0.8 g, 8 mmol) was added with intense
stirring to a mixture of oxazolidine 1b (0.45 g, 2 mmol) and
copper bronze (0.1 g) in octane (10 mL) at 120 °C for 2.5 h.
Then the reaction mixture was stirred at this temperature for
45 min and cooled. The solvent was distilled off in vacuo. The
residue was separated on a column with silica gel using a 2 : 1
hexane—Et2O mixture as the eluent. After recrystallization
from 95% EtOH, ester 9 was obtained in a yield of 52 mg
(13%), m.p. 106—107 °C. Found (%): C, 72.78; H, 6.29;
N, 4.53. C18H19NO3. Calculated (%): C, 72.71; H, 6.44;
N, 4.71. IR, ν/cm–1: 2950 (C—H), 1740 (C=O), 1600, 1510,
1460, 1380, 1350, 1250, 1120, 1030, 980, 940. 1H NMR
(CDCl3), δ: 3.21 and 3.56 (both m, 1 H each, NCH2); 3.46 (s,
3 H, OMe); 3.99 (t, 2 H, OCH2, J = 5 Hz); 4.32 and 5.03
(both d, 1 H each, H(3), H(2), J = 6 Hz); 6.98—7.08 and
7.28—7.48 (both m, 3 H and 7 H, Ar).
Methyl diazoacetate,6 3-ethyl-2-phenyloxazolidine (1a),7
and 2,3-diphenyloxazolidine (1b)7 were synthesized according
to known procedures.
The reaction of 3-ethyl-2-phenyloxazolidine (1a) with
methoxycarbonylcarbene. Methyl diazoacetate (1.5 g, 15 mmol)
was added with intense stirring to a mixture of oxazolidine 1a
(0.8 g, 4.5 mmol) and copper bronze (0.15 g) in octane
(15 mL) at 120 °C during 3 h. The reaction mixture was stirred
at this temperature for 30 min and then cooled. The solvent
was distilled off in vacuo. According to the GLC data, the
mixture contained dimethyl maleate, dimethyl fumarate, me-
thyl cinnamate, methyl morpholinecarboxylates 2 and 3, and
methyl oxazepanecarboxylate 4.
Separation of the reaction mixture on a column with silica
gel using a 1 : 1 hexane—Et2O mixture as the eluent afforded a
fraction (0.15 g, 13%), which contained primarily a mixture of
methyl trans-2-phenylmorpholine-3-carboxylate (2) (Ir = 1736)
and methyl trans-3-phenylmorpholine-2-carboxylate (3)
(Ir = 1711) as well as the minor components with Ir = 1726
and 1756. The latter were, apparently, geometric isomers of
the above-mentioned regioisomers. MS, m/z (Irel (%)): com-
pound 2 — 249 [M]+ (0.6), 191 (14), 190 [M – CO2Me]+
(100), 143 (6), 128 (11), 115 (7), 105 (8), 91 (8), 84 (8), 83
(11), 77 (11), 59 (7), 56 [CHNEt]+ (68), 55 (7), 54 (5);
compound 3 — 249 [M]+ (19), 191 (5), 190 [M – CO2Me]+
(33), 162 (9), 161 (54), 160 [M – CO2Me – CHOH]+ (94),
146 (14), 133 [PhCHNEt]+ (35), 132 [PhCNEt]+ (100), 131
(13), 130 (5), 121 (6), 119 (7), 118 [PhCHNCH2]+ (66), 117
(5), 105 (18), 104 [PhCNH]+ (37), 103 (12), 100 (5), 91 (36),
78 (6), 77 (15), 70 (6), 65 (6), 59 (7), 55 (29).
The solvent was evaporated from the fraction (0.38 g)
containing diester 4 and the residue was recrystallized from
95% EtOH to isolate dimethyl (5S,6R,7R)-4-ethyl-7-phenyl-
1,4-oxazepane-5,6-dicarboxylate (4) in a yield of 0.29 g (30%),
m.p. 61—62 °C. Found (%): C, 63.56; H, 7.02; N, 4.18.
C17H23NO5. Calculated (%): C, 63.54; H, 7.21; N, 4.36. IR,
ν/cm–1: 2960 (C—H), 1730 (C=O), 1600, 1520, 1450, 1360,
1250, 1120, 1080, 1010. 1H NMR (CDCl3), δ: 1.03 (t, 3 H,
Me, J = 7 Hz); 2.72 (dt, 1 H, H(3), J = 14 Hz, J = 3 Hz);
2.85 (m, 2 H, CH2); 3.37 (ddd, 1 H, H(3), J = 14 Hz,
J = 12 Hz, J = 3 Hz); 3.44 and 3.62 (both s, 3 H each,
2 OMe); 3.59 (t, 1 H, H(6), J = 7 Hz); 3.73 (td, 1 H, H(2),
J = 12 Hz, J = 3 Hz); 4.02 (dt, 1 H, H(2), J = 12 Hz,
J = 3 Hz); 4.16 and 5.17 (both d, 1 H each, H(5), H(7),
J = 7 Hz); 7.24—7.33 (m, 5 H, Ar). 13C NMR, δ: 14.1 (q),
50.6 (t), 51.4 (q), 51.7 (q), 57.3 (d), 65.1 (d), 72.0 (t), 80.9
(d), 126.1 (d), 127.3 (d), 128.0 (d), 142.3 (s), 172.4 (s), 172.7
(s). MS, m/z (Irel (%)): 321 [M]+ (1.6), 263 (11), 262
[M – CO2Me]+ (63), 234 (11), 232 (14), 200 (5), 188 (7), 156
(10), 155 [M – CO2Me – PhCHOH]+ (100), 131 (8), 129
(17), 128 (14), 116 (10), 115 (14), 104 (5), 100 (29), 98 (17),
97 (5), 96 (10), 91 (7), 82 (5), 77 (12), 72 (11), 70 (5), 69 (6),
68 (6), 59 (28), 58 (5), 56 (24).
X-ray diffraction analysis of compound 4. Single crystals of
diester 4 were obtained by crystallization from EtOH. X-ray
diffraction data were collected on a Hilger & Watts-Y290
diffractometer (graphite monochromator, λ(Cu-Kα)
=
1.54178 Å, 173 K, θ/2θ scanning technique) using a crystal of
dimensions 0.8½0.5½0.4 mm. The crystals are triclinic, a =
6.9538(9) Å, b = 10.0732(12) Å, c = 12.256(2) Å, α = 75.55(1)°,
β = 87.45(1)°, γ = 83.63(1)°, V = 819.35(20) Å3, Z = 2,
–3
M
=
321.36, space group P1, dcalc
=
1.302
g
cm
,
F(000) = 344.0, µ = 0.790, Rint = 3441, the number of
reflections with I ≥ 2σ(I) was 3378, the number of the param-
eters in the refinement was 235, R1(I ≥ 2σ(I )) = 0.071,
wR2 = 0.1251. The absorption correction was applied using
experimental azimuth scanning curves (Tmin/Tmax). The struc-
ture was solved by the direct method. The positional and
thermal parameters of the nonhydrogen atoms were refined by
Hydrochloride of trans-4-ethyl-2-phenylmorpholine-3-car-
boxylic acid (8). A 10% HCl solution (10 mL) was added to a

2148
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Molchanov et al.
the full-matrix least-squares method first isotropically and then
anisotropically. All calculations were carried out using the
SHELXL-97 program package.
The principal bond lengths, bond angles, and dihedral
angles are given in Tables 1—3, respectively. The complete
crystallographic parameters for compound 4 were deposited
with the Cambridge Structural Database (CCDC-163325).
4. B. V. Ioffe, R. R. Kostikov, and V. V. Razin, Fizicheskie
metody opredeleniya stroeniya organicheskikh soedinenii [Physi-
cal Methods for the Structure Determination of Organic Com-
pounds], Vysshaya Shkola, Moscow, 1984, 316 pp. (in
Russian).
5. B. V. Stolyarov, I. M. Savinov, A. G. Vitenberg, L. A.
Kartsova, I. G. Zenkevich, V. I. Kalmanovskii, and Yu. A.
Kalambet, Prakticheskaya gazovaya i zhidkostnaya khroma-
tografiya [Practical Gas and Liquid Chromatography],
Izd-vo St. Peterburgskogo Universiteta, St. Petersburg, 1999,
612 pp. (in Russian).
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Received January 29, 2001;
in revised form May 16, 2001