A simple route to morpholine derivatives via copper-acetylide addition to carbodiimide in the presence of oxiranes

Article abstract of DOI:10.1002/jhet.3770

A novel catalytic multicomponent reaction for the synthesis of morpholine derivatives has been reported. The reactions involve terminal alkynes, carbodiimides, and oxiranes using [Cu (CH₃CN)₄]PF₆, ^tBuOLi, and TB

Full text of DOI:10.1002/jhet.3770

Received: 17 June 2019
DOI: 10.1002/jhet.3770
Revised: 28 August 2019
Accepted: 24 September 2019
A R T I C L E
A simple route to morpholine derivatives via copper‐
acetylide addition to carbodiimide in the presence of
oxiranes
Alireza Samzadeh‐Kermani
Chemistry Department, Faculty of
Abstract
Science, University of Zabol, Zabol, Iran
A novel catalytic multicomponent reaction for the synthesis of morpholine
Correspondence
Alireza Samzadeh‐Kermani, Chemistry
Department, Faculty of Science,
derivatives has been reported. The reactions involve terminal alkynes,
t
carbodiimides, and oxiranes using [Cu (CH3CN)4]PF6, BuOLi, and TBPAc in
University of Zabol. Zabol, Iran.
Email: drsamzadeh@gmail.com;
arsamzadeh@uoz.ac.ir
anhydrous NMP. Aryl and heteroaromatic terminal alkynes were tolerated.
Carbodiimides could be symmetrical and unsymmetrical substrates with aryl
or alkyl substituents. The reaction exhibited a good regioselectivity when
unsymmetrical carbodiimides were employed.
1 | INTRODUCTION
Ghazanfarpour‐Darjani reported a novel addition of
metal acetylides to carbon disulfide at ambient conditions
Among the methods developed for the synthesis of hetero-
cyclic compounds, the domino ring opening/cyclization
reactions of oxiranes or aziridines with appropriate reac-
tion partners have found much interest in organic chemis-
try.[1–4] The easy handling, high stability, and low cost of
oxiranes have made them among the most versatile
starting materials both in laboratory and in industrial
usage.[5–8] As far as we could ascertain, the regioselectivity
of the ring opening reaction of oxiranes with different
nucleophiles is very sensitive to electronic as well as steric
effects of substrates and reaction media.[9–13]
On the other hand, nucleophilic addition of metal
acetylides to appropriate electrophiles has been broadly
explored protocol for construction of corresponding pro-
pargyl motifs. For example, Potuganti et al reported the
first direct addition of alkyne to ketones in the presence
of isocyanates for the synthesis of spiro oxazolidinone
derivatives.[14] Armas et al developed an asymmetric
alkynylation of imines by cooperative hydrogen bonding
and metal catalysis.[15] Yooa and Lia have reported a
copper‐catalyzed four‐component coupling between alde-
hydes, amines, alkynes, and carbon dioxide to form
oxazolidinone skeletons.[16] Our group reported the first
nucleophilic addition of metal acetylides to isothiocya-
nates to form oxathian‐3‐imine derivatives.[17]
using oxirane as third coupling partner.[18] Patil and Raut
developed a cooperative catalytic system for synthesis of
quinolones based on nucleophilic additions of copper
acetylide to 2‐aminobenzaldehyde.[19] In spite of copper
acetylide importance in preparation of various organic
skeletons, the number of reports for the reaction of
metals acetylide with carbodiimides remains scarce most
likely due to the its lower reactivity compared with alde-
hydes and imines. The metal‐catalyzed addition of termi-
nal alkynes to carbodiimides by half‐sandwich rare earth
metal complexes, LiN (SiMe3)2, or Ru clusters have been
reported, previously.[20,21] Xu et al have also reported a
highly efficient addition reaction involving copper
acetylides and carbodiimides using acid chlorides both
as activating agent and substrates.[22] Recently,
tetrabutylphosphonium salts have been used as efficient
organocatalysts in activation of amide derivatives.[23]
These results encouraged us to examine the efficiency of
tetrabutylphosphonium salts as an organocatalyst catalyst
in a reaction involving copper acetylides, carbodiimides,
and oxiranes for the synthesis of morpholine derivatives.
The morpholine‐containing building blocks exhibit wide
range of biological activities such as antibacterial, anti-
fungal, antiviral, anti‐inflammatory, anticancer, and anti-
oxidant activity.[24–26]
J Heterocyclic Chem. 2019;1–9.
wileyonlinelibrary.com/journal/jhet
© 2019 Wiley Periodicals, Inc.
1

2
SAMZADEH‐KERMANI
Initially, we used phenyl acetylene (1a), N,N′‐diisopro-
reaction, NMP afforded a better yield (entry 1 vs entries
10–15). Clearly, the choice of base had a great effect on
the outcome of the reaction (entries 16–19). Both key
steps (Scheme 1, formation of propargylic amidine 6 and
ring‐opened intermediate 7) in the reaction sequence
(Scheme 1) should benefit from a more electrophilic
counterion associated with tert‐butoxide ion; however,
Li2CO3 was not a good choice for this reaction, most
likely due to the low solubility in such organic media.
The reaction showed also a great dependence into the
nature of the additive (entries 20–22). The reaction was
not productive in the absence of quaternary phospho-
nium salt (entry 23). It is worth mentioning that the reac-
tions conducted in lower temperatures did not afford the
desired product in acceptable yields (not shown in
Table 1).
pylcarbodiimide (2a), and methyl oxirane (3a) as the
t
starting materials, CuI as precatalyst, and BuOLi as base
in NMP at 60°C. The desired product 4a was obtained
only in 24% (Table 1, entry 1). Encouraged by this result,
different copper salts were screened (entries 1–4). Of the
catalyst examined, only [Cu (CH3CN)4]PF6 afforded a
better yield (entry 4). The use of copper (II) salts
completely suppressed the formation of the desired prod-
uct 4a (entries 5–6). The use of Au(I) salts led to a sub-
stantial increase in the yields of 4a; however, the
reaction in the presence of AgOTf was unsatisfactory
(entries 7–9). Among the solvents examined in the
TABLE 1 Optimization of reaction conditionsa
The substrates scope was then investigated with
respect to various terminal alkynes and oxiranes
(Table 2). Replacing the methyl substituent on the oxi-
rane with ethyl group had little effect on the outcome of
the reaction (entries 1–2). We found that enlarging the
alkyl substituents on oxiranes did not affect the reaction
in appreciable manners, giving products 4b‐c in good
yields (entries 3–4). Additionally, the reaction of gem‐
disubstituted oxirane 2e proceeded smoothly to afford
the corresponding morpholine compound 4e only in
62% yield, most likely due to the back strain of alkyl
groups (entry 5). The reaction of 2‐(phenoxymethyl)oxi-
rane (2f) could be performed cleanly and the product
formed in excellent yield (entry 6). If the alkyl branch
of the oxirane is replaced by a six‐membered ring, the
yield is increased, while the oxirane derived from
cycloheptene afforded the product only in moderate yield
(entries 7–8). Oxirane containing tert‐butyl group was
also tolerated; however, the corresponding product was
obtained only in 58% yield (entry 9). The reaction of 2‐
phenyloxirane (2j) is of much interest because of the issue
of the regioselectivity in the ring opening of oxirane and
hence formation of product. The difference in reactivity
was reflected in the reaction of 2j, where the attack exclu-
sively occurred at the internal carbon of oxirane (entry
10). Hetero‐aromatic alkynes 1b‐c were also suitable for
this transformation, affording the corresponding
morpholine skeletons in good yields (entries 11–12). The
reaction with aliphatic terminal alkyne 1f required higher
termperature to afford the desired compound 4 m in
acceptable yield (entry 13). This result indicated that π‐
electrons of the phenyl group of the phenyl acetylene
might coordinate to the copper catalyst, thereby affects
the nucleophilic attack of metal acetylide on
carbodiimide. For the bulky oxirane 2 k, the two
regioisomer products (internal attacked product 3n and
terminal attacked product 3n', respectively) were formed
Entry
Catalyst Additive Base
Solvent
1
2
3
4
5
6
7
8
9
CuI
TBPAc
TBPAc
TBPAc
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
DIPEA
tBuOK
NMP
NMP
NMP
NMP
NMP
NMP
NMP
NMP
NMP
MeCN
EtOH
DMF
29
CuCl
Traces
36
CuBr.SMe2
[cu (CH3CN)4]PF6 TBPAc
84
Cu (OAc)2
Cu (OTf)2
AuCl
TBPAc
TBPAc
TBPAc
TBPAc
TBPAc
Traces
Traces
53
PPh3AuOTf
AgOTf
71
Traces
64
10 [cu (CH3CN)4]PF6 TBPAc
11 [cu (CH3CN)4]PF6 TBPAc
12 [cu (CH3CN)4]PF6 TBPAc
13 [cu (CH3CN)4]PF6 TBPAc
14 [cu (CH3CN)4]PF6 TBPAc
15 [cu (CH3CN)4]PF6 TBPAc
16 [cu (CH3CN)4]PF6 TBPAc
17 [cu (CH3CN)4]PF6 TBPAc
18 [cu (CH3CN)4]PF6 TBPAc
19 [cu (CH3CN)4]PF6 TBPAc
20 [cu (CH3CN)4]PF6 TBPBr
21 [cu (CH3CN)4]PF6 TBAAc
22 [cu (CH3CN)4]PF6 CTAB
Traces
50
DMSO 28
Toluene Traces
THF
NMP
NMP
17
Traces
23c
tBuONa NMP
Traces
Tracesb
39
Li2CO3
tBuOLi
tBuOLi
tBuOLi
tBuOLi
NMP
NMP
NMP
NMP
NMP
17
38
23 [cu (CH3CN)4]PF6
‐
16
aReaction conditions: 1a (1.0 mmol), 2a (1.5 mmol), 3a (1.0 mmol), catalyst
(0.1 mmol), additive (0.1 mmol), base (1.0 mmol), and ground 3‐Å molecular
sieves (250 mg) in solvent (3 mL) at 60°C for 18 h under Ar.
bRecovery of 1a in 85% yield..

SAMZADEH‐KERMANI
3
SCHEME 1 Control experiments
TABLE 2 Synthesis of functionalized 1,4‐morpholines with various alkynes and oxiranesa
Entry
Alkyne
R1
Oxirane
R2, R3, R4
Yield, %b
1
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1d
1e
1f
Ph
2a
2b
2c
2d
2e
2f
Me, H, H
4a, 84
2
Ph
Et, H, H
4b, 79
3
Ph
(CH3)2CHOCH2, H, H
CH2CHCH2OCH2, H, H
C3H7, CH3, H
PhOCH2, H, H
–(CH2)4–, H
–(CH2)5–, H
(CH3)3C, H, H
Ph, H, H
4c, 81
4
Ph
4d, 76
4e, 67c
5
Ph
6
Ph
4f, 89
7
Ph
2 g
2 h
2i
4 g, 92
4 h, 53
4i, 58c
8
Ph
9
Ph
10
11
12
13
14
Ph
2j
4j, 87
2‐Furyl
2‐Thienyl
n‐Bu
Ph
2a
2a
2a
2 k
Me, H, H
4 k, 89
4 l, 76c
4 m, 72d
4n:4n' = 3:1, 79e
Me, H, H
Me, H, H
1a
CH3, CH3, CH3
aReaction conditions: 1 (1.0 mmol), 2a (1.5 mmol), 3 (1.0 mmol), [Cu (CH3CN)4]PF6 (0.1 mmol), TBPAc (0.1 mmol), tBuOLi (1.0 mmol), and ground 3‐Å molec-
ular sieves (250 mg) in NMP (3 mL) at 60°C for 18 h under Ar.
bIsolated yields were reported.
cReaction mixture was stirred for 22 h.
dReaction mixture was stirred at 85°C for 22 h.
eProduct ratio was determined by 1H NMR..
in a ratio of 3:1 (entry 14). It could be deduced that the
reaction with highly substituted oxirane proceeded
through a SN1 pathway.
A range of carbodiimides were also examined under
the optimized conditions (Table 3). The use of 2b (R1,
R2 = Cy) as a substrate afforded 4 m in good yield (entry
1). Additionally, phenyl‐substituted carbodiimide 2c gave
the product with acceptable yield (entry 2).
Carbodiimides with both aliphatic and aromatic substitu-
ents were also examined (entries 3–4). To our delight,
only l‐4‐phenylmorpholines were detected in crude reac-
tion mixture analyses, indicating a high regioselectivity

4
SAMZADEH‐KERMANI
TABLE 3 Synthesis of functionalized 1,4‐morpholines with vari-
in the presence of copper catalyst and the base source
(Scheme 1, entry 3).
ous carbodiimidesa
As shown in Scheme 2, the activation of 3a with
tetrabutylphosphonium acetate (TBPAc) weakened the
carbon–oxygen bond and produced an activated species
that is attacked by anionic adduct derived from the reac-
tion of copper acetylide and carbodiimide. While TBPAc
system exhibited somewhat Lewis acidic nature, the reac-
tion did not proceed through the SN1‐like pathway as no
products arising from Meinwald rearrangement are
detected by crude reaction mixture analyses. Mechanisti-
cally, copper(I) coordinates with the phenyl acetylene
activating the terminal C–H bond. The abstraction of
Entry
Carbodiimide
R1
R2
Yield, %b
1
2
3
4
2b
2c
2d
2e
Cy
Cy
Ph
Ph
Ph
4o, 78
4p, 85
4q, 73
4r, 69
Ph
Cy
n‐Bu
t
the terminal proton easily by BuOLi leads to the forma-
aReaction conditions: 1a (1.0 mmol), 2 (1.5 mmol), 3a (1.0 mmol), [Cu
(CH3CN)4]PF6 (0.1 mmol), TBPAc (0.1 mmol), tBuOLi (1.0 mmol), and
ground 3‐Å molecular sieves (250 mg) in NMP (3 mL) at 60°C for 18 h under
Ar.
tion of copper acetylide 7. Copper acetylide then attacks
the carbodiimide carbon in the presence of TBPAc/Li+
and afford the corresponding phenylpropiolimidamide 8.
The adduct then attacked on oxirane to give 9. The alkox-
ide group of propargylic amidine 9 participated in the
nucleophilic addition to the triple bond by intramolecular
6‐exo cyclization to give 10. Finally, the desired product 4
was achieved by protonolyse of intermediate 10
(Scheme 1).
In summary, we have succeeded in the development of
the direct synthesis of 1,4‐morpholine skeletons, and this
process represents a novel example of catalytic multicom-
ponent reactions. This copper‐catalyzed reaction demon-
strates good functional group tolerance and acceptable
yields. Further studies of this type of reaction and explo-
ration of further applications are underway in our labora-
tory. The present protocol showed a high regioselectivity
when unsymmetrical carbodiimides were employed.
bIsolated yields were reported.
for the reaction. An outcome we attributed to the differ-
ence in stability of the resenconce structures using
unsymmetrical carbodiimides (species 8 in Scheme 2).
To get insight on the detail of the reaction pathway,
the reaction was performed in stepwise manner, and the
results are summurized in Scheme 1. The reaction of phe-
nyl acetylene with carbodiimide was performed in differ-
ent conditions. Control experiments revealed that the
presence of copper catalyst, a base source, and TBPAc
are necessary for the formation of the desired propargylic
amidine 5 (Scheme 1, entry 1). Additionally, control
experiments indicated that tBuOLi and TBPAc are
involved in ring opening of oxirane with species 5
(Scheme 1, entry 2). Eventually, electrophilic cyclization
of alkynol 6 across with C–C triple bond proceeded only
2 | EXPERIMENTAL
Reagents, catalysts, and solvents were obtained from
Merck. All the solvents were dried and degassed before
use. Melting points were measured with Electrothermal‐
9100 apparatus. Infrared (IR) spectra were recorded with
1
Shimadzu IR‐460 spectrometer. H and 13C NMR spectra
were recorded with Bruker DRX‐500 AVANCE instru-
ment; in CDCl3 at 500 and 125 MHz, resp; δ in ppm, J
in Hz. Mass spectra were recorded with EIMS (70 eV):
Finnigan‐MAT‐8430 mass spectrometer, in m/z. Elemen-
tal analyses (C, H, N) were performed with a Heraeus
CHN‐O‐Rapid analyzer. The results agreed favorably with
the calculated values. Column chromatography was per-
formed using Silica gel 60 (particle size 63–200 μm)
(Merck, item number 7734–3). Thin‐layer chromatogra-
phy (TLC) was performed using Silica gel 60 (Merck, item
number 116835).
SCHEME
morpholine skeletons
2
Plausible mechanism for the formation of

SAMZADEH‐KERMANI
5
4.11–4.23 (1 H, m, CH), 5.93 (1 H, s, CH), 7.25–7.40 (3
H, m, 3 CH), 7.66 (2 H, d, 3J = 7.3 Hz, 2 CH). 13C
NMR (125.7 MHz, CDCl3): δC = 11.2 (Me), 22.1 (2 Me),
24.7 (2 Me), 29.1 (CH2), 45.2 (CH), 49.1 (CH2), 58.2
(CH), 76.1 (CH), 110.1 (CH), 126.5 (CH), 127.8 (2 CH),
130.7 (2 CH), 134.1 (C), 142.1 (C), 162.4 (C). MS: m/z
(%) = 300 (M+, 3), 257 (11), 228 (18), 186 (36), 111
(40), 97 (70), 77 (100). Anal. Calcd for C19H28N2O
(300.45): C, 75.96, H, 9.39, N, 9.32. Found: C, 76.22, H,
9.61, N, 9.55.
2.1 | General procedure for synthesis 4
A mixture of terminal alkyne (1.0 mmol), [Cu (CH3CN)
4]PF6 (0.1 mmol), TBPAc (0.1 mmol), tBuOLi (1.0 mmol),
carbodiimide (1.5 mmol), and ground 3‐Å molecular
sieves (250 mg) in NMP (3.0 mL) was stirred at 25°C
under Ar. After 30 minutes, oxirane (1.0 mmol in 1.0‐
mL anhydrous NMP) was slowly added, and the
resulting yellowish mixture was warmed up to 60°C.
Stirring was continued for 18 hours under Ar. After
completion of the reaction (TLC monitoring), it was
diluted by EtOAc (5 mL) and a saturated NH4Cl solution
(5 mL). The mixture stirred for additional 30 minutes,
and two layers were separated. The aqueous layer was
then extracted with EtOAc (10 mL × 3). The combined
organic layers were washed with water (10 mL) and
brine (10 mL), dried over MgSO4, filtered, and concen-
trated in vacuo. The residue was purified by chromatog-
raphy (silica gel, hexane: EtOAc 4:1) to give the pure
product.
2.4 | 2‐Benzylidene‐6‐(isopropoxymethyl)‐
N,4‐diisopropylmorpholine‐3‐imine (4c)
Pale yellow oil. Yield: 0.28 g (81%). FTIR (KBr) νmax
:
3017, 2987, 2246, 1619, 1556, 1282, 1085. 1H NMR
3
(500.1 MHz, CDCl3): δH = 1.10 (6 H, d, J = 6.0 Hz, 2
Me), 1.18 (6 H, d, 3J = 5.5 Hz, Me), 1.32 (6 H, d,
3J = 6.0 Hz, 2 Me), 2.90–3.15 (2 H, m, 2 CH), 3.43–4.38
(5 H, m, 5 CH), 4.21–4.34 (1 H, m, CH), 5.88 (1 H, s,
CH), 7.27–7.42 (3 H, m, 3 CH), 7.62 (2 H, d,
3J = 7.0 Hz, 2 CH). 13C NMR (125.7 MHz, CDCl3):
δC = 21.6 (2 Me), 23.8 (2 Me), 25.4 (2 Me), 41.9 (CH),
47.3 (CH2), 55.2 (CH), 67.4 (CH2), 73.5 (CH), 80.1 (CH),
113.7 (CH), 126.8 (CH), 128.2 (2 CH), 130.1 (2 CH),
133.4 (C), 145.2 (C), 161.1 (C). MS: m/z (%) = 344 (M+,
1), 301 (9), 259 (22), 187 (39), 111 (55), 97 (84), 77 (100).
Anal. Calcd for C21H32N2O2 (344.50): C, 73.22, H, 9.36,
N, 8.13. Found: C, 73.41, H, 9.57, N, 8.29.
2.2 | 2‐Benzylidene‐N,4‐diisopropyl‐6‐
methylmorpholine‐3‐imine (4a)
Pale yellow oil. Yield: 0.24 g (84%). Fourier transform
infrared (FTIR) (KBr) νmax: 3001, 2991, 1608, 1532,
1467, 1298, 1078. 1H NMR (500.1 MHz, CDCl3): δH = 1.16
3
3
(6 H, d, J = 6.0 Hz, 2 Me), 1.22 (3 H, d, J = 5.7 Hz,
3
Me), 1.30 (6 H, d, J = 6.2 Hz, 2 Me), 3.08–3.23 (2 H,
m, 2 CH), 3.42 (1 H, dd, J = 11.2 Hz, J = 9.7 Hz,
2
3
2
3
CH), 3.79 (1 H, dd, J = 11.2 Hz, J = 5.3 Hz, CH),
3.90–4.02 (1 H, m, CH), 5.90 (1 H, s, CH), 7.27–7.44 (3
H, m, 3 CH), 7.61 (2 H, d, 3J = 7.1 Hz, 2 CH). 13C
NMR (125.7 MHz, CDCl3): δC = 17.9 (Me), 22.5 (2
Me), 24.1 (2 Me), 47.3 (CH2), 49.9 (CH), 59.8 (CH),
71.5 (CH), 114.2 (CH), 126.1 (CH), 127.9 (2 CH), 130.4
(2 CH), 133.7 (C), 144.4 (C), 163.1 (C). MS: m/z
(%) = 286 (M+, 2), 243 (12), 202 (34), 97 (89), 91 (51),
82 (67), 77 (100). Anal. Calcd for C18H26N2O (286.42):
C, 75.48, H, 9.15, N, 9.78. Found: C, 75.66, H, 9.34,
N, 9.94.
2.5 | 6‐((Allyloxy)methyl)‐2‐benzylidene‐
N,4‐diisopropylmorpholine‐3‐imine (4d)
Pale yellow oil. Yield: 0.26 g (76%). FTIR (KBr) νmax
:
3026, 2980, 1635, 1610, 1525, 1290, 1124. 1H NMR
3
(500.1 MHz, CDCl3): δH = 1.14 (6 H, d, J = 5.8 Hz, 2
3
Me), 1.30 (6 H, d, J = 6.1 Hz, Me), 2.94–3.18 (2 H, m, 2
CH), 3.37–4.31 (6 H, m, 6 CH), 4.47–4.60 (1 H, m, CH),
5.36–5.53 (2 H, m, 2 CH), 5.81 (1 H, s, CH), 6.22–6.34 (1
H, m, CH), 7.26–7.44 (3 H, m, 3 CH), 7.65 (2 H, d,
3J = 7.3 Hz, 2 CH). 13C NMR (125.7 MHz, CDCl3):
δC = 22.1 (2 Me), 24.5 (2 Me), 43.3 (CH), 49.8 (CH2),
55.1 (CH), 65.7 (CH2), 69.2 (CH2), 78.1 (CH), 110.7
(CH), 118.3 (CH), 126.1 (CH), 129.3 (2 CH), 131.4 (2
CH), 132.7 (C), 135.1 (CH), 144.1 (C), 163.7 (C). MS: m/
z (%) = 342 (M+, 1), 299 (11), 259 (24), 218 (45), 187
(35), 97 (87), 77 (100). Anal. Calcd for C21H30N2O2
(342.48): C, 73.65, H, 8.83, N, 8.18. Found: C, 73.82, H,
9.06, N, 8.37.
2.3 | 2‐Benzylidene‐6‐ethyl‐N,4‐
diisopropylmorpholine‐3‐imine (4b)
Pale yellow oil. Yield: 0.24 g (79%). FTIR (KBr) νmax
:
3024, 2968, 1611, 1532, 1287, 1115. 1H NMR
3
(500.1 MHz, CDCl3): δH = 0.83 (3 H, t, J = 5.9 Hz,
Me), 1.13 (6 H, d, 3J = 5.8 Hz, 2 Me), 1.28 (6 H, d,
3J = 6.0 Hz, 2 Me), 1.75 (2 H, m, CH2), 3.01–3.25 (2 H,
2
3
m, 2 CH), 3.55 (1 H, dd, J = 11.7 Hz, J = 10.1 Hz,
2
3
CH), 3.79 (1 H, dd, J = 11.7 Hz, J = 5.7 Hz, CH),

6
SAMZADEH‐KERMANI
CH), 7.26–7.43 (3 H, m, 3 CH), 7.58 (2 H, d,
3J = 7.2 Hz, 2 CH). 13C NMR (125.7 MHz, CDCl3):
δC = 21.3 (2 Me), 25.2 (2 Me), 27.2 (CH2), 28.5 (CH2),
30.3 (CH2), 34.1 (CH2), 44.1 (CH), 55.8 (CH), 70.1 (CH),
82.3 (CH), 113.2 (CH), 127.0 (CH), 128.9 (2 CH), 131.4
(2 CH), 133.7 (C), 142.1 (C), 162.5 (C). MS: m/z
(%) = 326 (M+, 1), 283 (17), 153 (57), 181 (35), 97 (81),
77 (100). Anal. Calcd for C21H30N2O (326.48): C, 77.26,
H, 9.26, N, 8.58. Found: C, 77.44, H, 9.43, N, 8.70.
2.6 | 2‐Benzylidene‐N,4‐diisopropyl‐6‐
methyl‐6‐propylmorpholine‐3‐imine (4e)
Light brown solid; M.P: 91–93°C. Yield: 0.22 g (67%).
FTIR (KBr) νmax: 3021, 2987, 1613, 1536, 1267, 1102. H
1
NMR (500.1 MHz, CDCl3): δH
= 0.87 (3 H, t,
3
3J = 5.9 Hz, Me), 1.11 (6 H, d, J = 6.1 Hz, 2 Me), 1.27
3
(6 H, d, J = 6.0 Hz, Me), 1.38–1.59 (7 H, m, 2 CH2 and
Me), 2.87–3.11 (2 H, m, 2 CH), 3.78–4.02 (2 H, m, 2
CH), 5.87 (1 H, s, CH), 7.24–7.43 (3 H, m, 3 CH), 7.63
(2 H, d, 3J = 7.0 Hz, 2 CH). 13C NMR (125.7 MHz,
CDCl3): δC = 13.2 (Me), 18.4 (CH2), 20.1 (Me), 22.1 (2
Me), 24.0 (2 Me), 39.7 (CH2), 45.1 (CH), 56.3 (CH), 64.1
(CH2), 80.3 (C), 113.2 (CH), 126.5 (CH), 128.7 (2 CH),
130.1 (2 CH), 133.4 (C), 143.7 (C), 162.5 (C). MS: m/z
(%) = 328 (M+, 1), 299 (11), 259 (24), 218 (45), 187 (35),
97 (87), 77 (100). Anal. Calcd for C21H32N2O (328.50): C,
76.78, H, 9.82, N, 8.53. Found: C, 76.61, H, 9.77, N, 8.70.
2.9 | 2‐Benzylidene‐N,4‐
diisopropyloctahydrocyclohepta[b][1,4]
oxazin‐3(2H)‐imine (4 h)
Pale yellow solid; M.P: 68–70°C. Yield: 0.18 g (53%). FTIR
1
(KBr) νmax: 3025, 2982, 1611, 1543, 1306, 1234. H NMR
3
(500.1 MHz, CDCl3): δH = 1.15 (6 H, d, J = 5.6 Hz, 2
3
Me), 1.31 (6 H, d, J = 6.0 Hz, Me), 1.34–2.08 (10 H, m,
2.7 | 2‐Benzylidene‐N,4‐diisopropyl‐6‐
(phenoxymethyl)morpholine‐3‐imine (4f)
10 CH), 2.52–2.83 (2 H, m, 2 CH), 2.96–3.05 (1 H, m,
CH), 3.68–3.75 (1 H, m, CH), 5.81 (1 H, s, CH), 7.25–
3
7.40 (3 H, m, 3 CH), 7.62 (2 H, d, J = 6.9 Hz, 2 CH).
Pale yellow oil. Yield: 0.34 g (89%). FTIR (KBr) νmax
:
13C NMR (125.7 MHz, CDCl3): δC = 21.5 (2 Me), 24.0 (2
Me), 25.1 (CH2), 27.2 (CH2), 28.5 (CH2), 29.4 (CH2), 32.6
(CH2), 45.2 (CH), 58.1 (CH), 64.3 (CH), 79.5 (CH), 113.6
(CH), 126.2 (CH), 128.5 (2 CH), 130.1 (2 CH), 132.9 (C),
142.5 (C), 163.8 (C). MS: m/z (%) = 340 (M+, 1), 297
(12), 257 (23), 167 (46), 97 (89), 77 (100). Anal. Calcd for
C22H32N2O (340.51): C, 77.60, H, 9.47, N, 8.23. Found:
C, 77.51, H, 9.42, N, 8.44.
3013, 2978, 1656, 1622, 1530, 1290, 1088. 1H NMR
3
(500.1 MHz, CDCl3): δH = 1.13 (6 H, d, J = 6.0 Hz, 2
3
Me), 1.30 (6 H, d, J = 5.8 Hz, Me), 2.71–2.98 (2 H, m, 2
2
3
CH), 3.67 (1 H, dd, J = 11.0 Hz, J = 9.2 Hz, CH), 3.89
2
3
(1 H, dd, J = 11.0 Hz, J = 5.2 Hz, CH), 4.11–4.27 (1 H,
m, CH), 4.34 (1 H, dd, J = 11.9 Hz, J = 9.5 Hz, CH),
4.65 (1 H, dd, J = 11.9 Hz, J = 4.7 Hz, CH), 5.84 (1 H,
2
3
2
3
3
s, CH), 6.89 (2 H, d, J = 7.0 Hz, CH), 7.03 (1 H, t,
3J = 6.8 Hz, CH), 7.19–7.45 (5 H, m, 5 CH), 7.61 (2 H,
d, J = 7.1 Hz, 2 CH). 13C NMR (125.7 MHz, CDCl3):
3
δC = 20.9 (2 Me), 24.7 (2 Me), 43.7 (CH), 49.2 (CH2),
56.1 (CH), 68.5 (CH2), 76.5 (CH), 110.4 (CH), 114.1 (2
CH), 121.2 (CH), 127.5 (CH), 128.4 (2 CH), 129.7 (2
CH), 130.8 (2 CH), 134.1 (C), 142.4 (C), 159.7 (C), 163.8
(C). MS: m/z (%) = 378 (M+, 1), 299 (11), 259 (24), 218
(45), 187 (35), 97 (87), 77 (100). Anal. Calcd for
C24H30N2O2 (378.52): C, 76.16, H, 7.99, N, 7.40. Found:
C, 76.61, H, 9.77, N, 7.62.
2.10 | 2‐Benzylidene‐6‐(tert‐butyl)‐N,4‐
diisopropylmorpholine‐3‐imine (4i)
Pale yellow oil. Yield: 0.19 g (58%). FTIR (KBr) νmax
:
3026, 2973, 1611, 1525, 1303, 1097. 1H NMR
(500.1 MHz, CDCl3): δH = 0.96 (9 H, s, 3 Me), 1.15 (6
3
3
H, d, J = 6.1 Hz, 2 Me), 1.53 (6 H, d, J = 6.0 Hz, 2
Me), 2.58–2.95 (2 H, m, 2 CH), 3.55 (1 H, dd,
2J = 12.6 Hz, 3J = 10.0 Hz, CH), 3.83 (1 H, dd,
2J = 12.6 Hz, J = 5.1 Hz, CH), 4.03–4.18 (1 H, m, CH),
3
2.8 | 2‐Benzylidene‐N,4‐
diisopropylhexahydro‐2H‐benzo[b][1,4]
oxazin‐3(4H)‐imine (4 g)
5.80 (1 H, s, CH), 7.29–7.43 (3 H, m, 3 CH), 7.63 (2 H,
d, 3J = 7.1 Hz, CH). 13C NMR (125.7 MHz, CDCl3):
δC = 21.1 (2 Me), 24.2 (2 Me), 28.2 (3 Me), 36.8 (C), 43.1
(CH), 50.5 (CH2), 60.4 (CH), 90.1 (C), 113.1 (CH), 126.5
(CH), 128.1 (2 CH), 131.5 (2 CH), 134.1 (C), 142.1 (C),
162.3 (C). MS: m/z (%) = 328 (M+, 1), 271 (23), 229 (19),
187 (49), 97 (81), 77 (100), 57 (91). Anal. Calcd for
C21H32N2O (328.50): C, 76.78, H, 9.82, N, 8.53. Found:
C, 70.87, H, 9.65, N, 8.39.
Pale yellow solid; M.P: 139–141°C. Yield: 0.30 g (92%).
1
FTIR (KBr) νmax: 3025, 2968, 1607, 1562, 1312, 1093. H
NMR (500.1 MHz, CDCl3): δH = 1.14 (6 H, d,
3
3J = 5.8 Hz, 2 Me), 1.33 (6 H, d, J = 6.1 Hz, Me), 1.43–
2.02 (8 H, m, 8 CH), 2.65–2.90 (2 H, m, 2 CH), 3.06–
3.18 (1 H, m, CH), 3.47–3.60 (1 H, m, CH), 5.80 (1 H, s,

SAMZADEH‐KERMANI
7
3
3
7.15 (1 H, d, J = 6.9 Hz, CH), 7.79 (1 H, d, J = 6.0 Hz,
CH). 13C NMR (125.7 MHz, CDCl3): δC = 17.8 (Me),
21.1 (2 Me), 25.2 (2 Me), 45.0 (CH), 57.4 (CH2), 61.2
(CH), 81.7 (CH), 103.6 (CH), 127.1 (CH), 129.5 (CH),
131.2 (CH), 139.2 (C), 147.0 (C), 162.1 (C). MS: m/z
(%) = 292 (M+, 1), 233 (17), 191 (35), 111 (63), 97 (100),
68 (52), 54 (41). Anal. Calcd for C16H24N2OS (292.44): C,
65.71, H, 8.27, N, 9.58. Found: C, 65.90, H, 8.51, N, 9.37.
2.11 | 2‐Benzylidene‐N,4‐diisopropyl‐5‐
phenylmorpholine‐3‐imine (4j)
Yellow solid; M.P: 73–75°C. Yield: 0.30 g (87%). FTIR
1
(KBr) νmax: 3017, 2988, 1607, 1561, 1324, 1078. H NMR
3
(500.1 MHz, CDCl3): δH = 1.12 (6 H, d, J = 5.7 Hz, 2
3
Me), 1.50 (6 H, d, J = 6.4 Hz, 2 Me), 2.67–2.92 (2 H, m,
2 CH), 4.42–4.55 (1 H, m, CH), 4.70 (1 H, dd,
2J = 12.2 Hz, 3J = 10.1 Hz, CH), 4.95 (1 H, dd,
3
2J = 12.2 Hz, J = 5.4 Hz, CH), 5.87 (1 H, s, CH), 7.19–
3
7.47 (8 H, m, 8 CH), 7.65 (2 H, d, J = 7.3 Hz, CH). 13C
NMR (125.7 MHz, CDCl3): δC = 21.3 (2 Me), 24.9 (2
Me), 44.6 (CH), 52.1 (CH), 67.1 (CH), 83.5 (CH2), 112.7
(CH), 126.1 (CH), 126.6 (2 CH), 127.5 (CH), 128.4 (2
CH), 130.1 (2 CH), 131.6 (2 CH), 133.4 (C), 138.6 (C),
142.6 (C), 162.9 (C). MS: m/z (%) = 348 (M+, 1), 305
(11), 263 (15), 187 (55), 97 (85), 77 (100), 54 (41). Anal.
Calcd for C23H28N2O (348.49): C, 79.27, H, 8.10, N, 8.04.
Found: C, 79.51, H, 8.23, N, 8.26.
2.14 | N,4‐dicyclohexyl‐6‐methyl‐2‐
pentylidenemorpholin‐3‐imine (4 m)
Colorless oil. Yield: 0.25 g (72%). FTIR (KBr) νmax: 3038,
2980, 1606, 1526, 1452, 1255, 1094. 1H NMR
3
(500.1 MHz, CDCl3): δH = 0.93 (3 H, t, J = 5.8 Hz,
3
Me), 1.22 (3 H, d, J = 5.6 Hz, Me), 1.30–2.13 (24 H, m,
3
3
12 CH2), 2.28 (1 H, td, J = 6.3 Hz, J = 5.0 Hz, CH),
2
3.05–3.10 (1 H, m, CH), 3.72 (1 H, dd, J = 12.1 Hz,
3J = 5.3 Hz, CH), 3.91 (1 H, dd, 2J = 12.1 Hz,
3J = 9.3 Hz, CH), 4.34 (1 H, m, CH), 4.89 (1 H, t,
3J = 5.8 Hz, CH), 5.25–5.30 (1 H, m, CH). 13C NMR
(125.7 MHz, CDCl3): δC = 15.2 (Me), 20.3 (Me), 24.1
(CH2), 25.4 (CH2), 26.1 (2 CH2), 26.3 (2 CH2), 28.1
(CH2), 28.7 (CH2), 31.6 (2 CH2), 34.1 (CH2), 53.8 (CH2),
60.4 (CH), 67.8 (CH), 76.2 (CH), 115.3 (CH), 139.9 (C),
164.1 (C). MS: m/z (%) = 346 (M+, 1), 331 (8), 249 (36),
179 (53), 98 (73), 83 (88), 82 (100). Anal. Calcd for
C22H38N2O (346.56): C, 76.25, H, 11.05, N, 8.08. Found:
C, 76.42, H, 11.23, N, 8.23.
2.12 | 2‐(Furan‐2‐ylmethylene)‐N,4‐
diisopropyl‐6‐methylmorpholine‐3‐imine
(4 k)
Yellow oil. Yield: 0.25 g (89%). FTIR (KBr) νmax: 3010,
2966, 1614, 1531, 1287, 1092. 1H NMR (500.1 MHz,
3
CDCl3): δH = 1.09 (6 H, d, J = 5.9 Hz, 2 Me), 1.25 (6
3
3
H, d, J = 6.0 Hz, 2 Me), 1.30 (3 H, d, J = 6.3 Hz, Me),
2.62–2.98 (2 H, m, 2 CH), 3.49–3.62 (1 H, m, CH), 3.89
2
3
(1 H, dd, J = 12.0 Hz, J = 8.9 Hz, CH), 4.05 (1 H, dd,
2J = 12.0 Hz, J = 5.2 Hz, CH), 5.80 (1 H, s, CH), 6.71
3
3
3
(1 H, t, J = 6.6 Hz, CH), 6.98 (1 H, d, J = 6.3 Hz, CH),
7.87 (1 H, d, J = 6.3 Hz, CH). 13C NMR (125.7 MHz,
3
CDCl3): δC = 19.1 (Me), 21.5 (2 Me), 24.5 (2 Me), 42.1
(CH), 53.1 (CH2), 57.9 (CH), 80.1 (CH), 112.1 (CH),
116.3 (CH), 119.1 (CH), 141.4 (C), 148.1 (C), 152.1 (C),
165.0 (C). MS: m/z (%) = 276 (M+, 1), 233 (17), 191 (35),
111 (63), 97 (100), 68 (52), 54 (41). Anal. Calcd for
C16H24N2O2 (276.38): C, 69.53, H, 8.75, N, 10.14. Found:
C, 69.42, H, 8.65, N, 10.22.
2.15 | 2‐Benzylidene‐N,4‐diisopropyl‐5,6‐
dimethyl‐5‐phenylmorpholin‐3‐imine (4n)
Colorless oil. Yield: 0.22 g (60%). FTIR (KBr) νmax: 3037,
2962, 1621, 1543, 1265, 1154. 1H NMR (500.1 MHz,
3
CDCl3): δH = 1.14 (6 H, d, J = 5.9 Hz, 2 Me), 1.22 (3
3
3
H, d, J = 5.5 Hz, Me), 1.47 (6 H, d, J = 6.1 Hz, 2 Me),
1.55 (3 H, s, Me), 2.77–2.83 (1 H, m, CH), 2.94–2.99 (1
3
H, m, CH), 4.53 (1 H, q, J = 5.5 Hz, CH), 5.70 (1 H, s,
2.13 | N,4‐diisopropyl‐6‐methyl‐2‐
(thiophen‐2‐ylmethylene)morpholine‐3‐
imine (4 l)
CH), 7.21–7.38 (6 H, m, 6 CH), 7.43 (2 H, d,
3J = 7.1 Hz, 2 CH), 7.69 (2 H, d, J = 7.1 Hz, 2 CH). 13C
3
NMR (125.7 MHz, CDCl3): δC = 20.7 (Me), 21.5 (2 Me),
23.9 (Me), 25.2 (2 Me), 47.6 (CH), 54.2 (CH), 70.7 (C),
88.1 (CH), 109.5 (CH), 125.7 (CH), 126.4 (CH), 128.6 (2
CH), 128.9 (2 CH), 129.4 (2 CH), 130.6 (2 CH), 133.7
(C), 136.1 (C), 142.1 (C), 163.1 (C). MS: m/z (%) = 376
(M+, 1), 346 (13), 305 (21), 215 (37), 158 (71), 82 (89), 77
(100). Anal. Calcd for C25H32N2O (376.54): C, 79.74, H,
8.57, N, 7.44. Found: C, 79.93, H, 8.72, N, 7.60.
Light brown oil. Yield: 0.22 g (76%). FTIR (KBr) νmax
:
3041, 2991, 1622, 1567, 1432, 1357, 1077. 1H NMR
3
(500.1 MHz, CDCl3): δH = 1.13 (6 H, d, J = 5.7 Hz, 2
Me), 1.24 (6 H, d, 3J = 6.2 Hz, 2 Me), 1.32 (3 H, d,
3J = 6.5 Hz, Me), 2.57–2.90 (2 H, m, 2 CH), 3.51–3.92 (2
2
3
H, m, 2 CH), 4.17 (1 H, dd, J = 12.4 Hz, J = 4.9 Hz,
3
CH), 5.72 (1 H, s, CH), 6.90 (1 H, t, J = 6.2 Hz, CH),

8
SAMZADEH‐KERMANI
3
d, J = 6.9 Hz, 2 CH). 13C NMR (125.7 MHz, CDCl3):
δC = 19.3 (Me), 26.1 (CH2), 28.3 (2 CH2), 34.1 (2 CH2),
61.3 (CH), 65.2 (CH2), 75.2 (CH), 112.1 (CH), 118.4 (2
CH), 121.3 (CH), 127.9 (2 CH), 129.1 (2 CH), 130.3 (2
CH), 134.3 (C), 141.2 (C), 143.7 (C), 162.1 (C). MS: m/z
(%) = 360 (M+, 1), 347 (10), 266 (23), 189 (65), 97 (83),
91 (45), 77 (100). Anal. Calcd for C24H28N2O (360.50): C,
79.96, H, 7.83, N, 7.77. Found: C, 79.81, H, 7.92, N, 7.82.
2.16 | 2‐Benzylidene‐N,4‐dicyclohexyl‐6‐
methylmorpholine‐3‐imine (4o)
Light brown solid; M.P: 102–104°C. Yield: 0.29 g (78%).
FTIR (KBr) νmax: 3012, 2976, 1614, 1553, 1301, 1092. H
1
NMR (500.1 MHz, CDCl3): δH = 1.18 (3 H, d,
3J = 5.9 Hz, Me), 1.32–2.01 (20 H, m, 20 CH), 2.85–2.98
(1 H, m, CH), 3.77–4.43 (3 H, m, 3 CH), 4.94–5.10 (1 H,
m, CH), 5.83 (1 H, s, CH), 7.28–7.43 (3 H, m, 3 CH),
3
7.63 (2 H, d, J = 7.1 Hz, CH). 13C NMR (125.7 MHz,
2.19 | 2‐Benzylidene‐N‐butyl‐6‐methyl‐4‐
phenylmorpholine‐3‐imine (4r)
CDCl3): δC = 19.1 (Me), 23.7 (CH2), 25.1 (2 CH2), 26.7
(2 CH2), 27.2 (CH2), 28.9 (2 CH2), 31.2 (2 CH2), 36.2 (2
CH2), 51.2 (CH2), 56.2 (CH), 64.9 (CH), 79.1 (CH), 112.5
(CH), 126.7 (CH), 127.9 (2 CH), 130.2 (2 CH), 134.1 (C),
141.5 (C), 162.5 (C). MS: m/z (%) = 366 (M+, 1), 283
(15), 269 (8), 187 (67), 97 (81), 83 (71), 77 (100). Anal.
Calcd for C24H34N2O (366.55): C, 78.64, H, 9.35, N, 7.64.
Found: C, 78.47, H, 9.17, N, 7.80.
Light yellow oil. Yield: 0.23 g (69%). FTIR (KBr) νmax
:
3017, 2971, 1621, 1543, 1341, 1241. 1H NMR
3
(500.1 MHz, CDCl3): δH = 0.83 (3 H, t, J = 5.9 Hz,
Me), 1.20–1.59 (7 H, m, Me and 3CH2), 3.52 (1 H, dd,
2J = 12.1 Hz, 3J = 10.1 Hz, CH), 3.87 (1 H, dd,
3
2J = 12.0 Hz, J = 5.4 Hz, CH), 4.13–4.38 (1 H, m, CH),
3
5.19 (1 H, s, CH), 6.63 (1 H, t, J = 6.9 Hz, CH), 6.84 (2
3
3
H, d, J = 7.1 Hz, 2 CH), 7.12 (2 H, t, J = 7.1 Hz, 2
CH), 7.27–7.42 (3 H, m, 3 CH), 7.62 (2 H, d,
3J = 7.1 Hz, CH). 13C NMR (125.7 MHz, CDCl3): δC = 13.8
(Me), 20.1 (Me), 24.2 (CH2), 36.4 (CH2), 56.1 (CH), 60.9
(CH2), 73.1 (CH), 115.7 (CH), 117.2 (2 CH), 121.1 (CH),
126.1 (CH), 127.8 (2 CH), 129.4 (2 CH), 131.1 (2 CH),
133.8 (C), 141.0 (C), 145.2 (C), 161.9 (C). MS: m/z
(%) = 334 (M+, 1), 319 (13), 264 (27), 187 (52), 97 (87),
91 (37), 77 (100). Anal. Calcd for C22H26N2O (334.46): C,
79.00, H, 7.84, N, 8.38. Found: C, 79.24, H, 7.71, N, 8.19.
2.17 | 2‐Benzylidene‐6‐methyl‐N,4‐
diphenylmorpholine‐3‐imine (4p)
Light brown solid; M.P: 89–91°C. Yield: 0.30 g (85%).
FTIR (KBr) νmax: 3032, 2983, 1624, 1561, 1325, 1165. H
1
NMR (500.1 MHz, CDCl3): δH = 1.20 (3 H, d,
3J = 5.7 Hz, Me), 3.67 (1 H, dd, 2J = 12.4 Hz,
3J = 5.9 Hz, CH), 3.90 (1 H, dd, 2J = 12.4 Hz,
3J = 9.4 Hz, CH), 4.25–4.34 (1 H, m, CH), 5.75 (1 H, s,
CH), 6.62 (1 H, t, 3J = 7.3 Hz, CH), 6.81 (2 H, d,
3
3J = 7.0 Hz, CH), 7.92 (2 H, d, J = 6.8 Hz, CH), 7.08–
7.21 (3 H, m, 3 CH), 7.26–7.44 (5 H, m, 5 CH), 7.60 (2
ORCID
3
H, d, J = 7.0 Hz, CH). 13C NMR (125.7 MHz, CDCl3):
Alireza Samzadeh‐Kermani
6183-6299
https://orcid.org/0000-0001-
δC = 20.3 (Me), 64.1 (CH2), 73.0 (CH), 113.2 (CH), 118.5
(2 CH), 121.3 (CH), 123.5 (2 CH), 126.2 (CH), 126.9
(CH), 128.7 (2 CH), 129.2 (2 CH), 130.5 (2 CH), 132.1 (2
CH), 133.2 (C), 142.1 (C), 145.2 (C), 151.7 (C), 163.1 (C).
MS: m/z (%) = 354 (M+, 1), 283 (15), 269 (8), 187 (67),
97 (81), 83 (71), 77 (100). Anal. Calcd for C24H22N2O
(354.45): C, 81.33, H, 6.26, N, 7.90. Found: C, 81.15, H,
6.15, N, 7.78.
REFERENCES AND NOTES
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2.18 | 2‐Benzylidene‐N‐cyclohexyl‐6‐
methyl‐4‐phenylmorpholine‐3‐imine (4q)
[4] N. Chauhan, S. Pradhan, M. K. Ghorai, J. Org. Chem 2019, 84,
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Light brown solid; M.P: 73–75°C. Yield: 0.26 g (73%).
FTIR (KBr) νmax: 3023, 2989, 1602, 1562, 1278, 1187. H
1
[6] Composites 1972, 3, 104.
NMR (500.1 MHz, CDCl3): δH = 1.29 (3 H, d,
3J = 5.7 Hz, Me), 1.32–2.01 (10 H, m, 10 CH), 3.56–3.86
(2 H, m, 2 CH), 4.17–4.30 (1 H, m, CH), 5.23 (1 H, s,
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3
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CH), 5.48–5.61 (1 H, m, CH), 6.52 (1 H, t, J = 6.5 Hz,
CH), 6.81 (2 H, d, 3J = 7.0 Hz, 2 CH), 7.19 (2 H, t,
3J = 7.0 Hz, CH), 7.26–7.45 (3 H, m, 3 CH), 7.60 (2 H,
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How to cite this article: Samzadeh‐Kermani A.
A simple route to morpholine derivatives via
copper‐acetylide addition to carbodiimide in the
presence of oxiranes. J Heterocyclic Chem. 2019;1–9.
https://doi.org/10.1002/jhet.3770
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