Hydrochloric acid as an efficient catalyst for intermolecular condensation of alcohols. A simple and highly efficient synthesis of unsymmetrical ethers from benzylic alcohols and alkanols

Article abstract of DOI:10.1134/S107042801509002X

Benzylic alcohols and diarylmethanols with electron-donating substituents in the aromatic ring reacted with aliphatic alcohols in the presence of a catalytic amount of HCl to give the corresponding alkyl arylmethyl ethers. The reactivity of diarylmethanols in the intermolecular dehydration depended on the nature of substituents in the aromatic rings and structure of aliphatic alcohol.

Full text of DOI:10.1134/S107042801509002X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2015, Vol. 51, No. 9, pp. 1217–1231. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © S.S. Mochalov, A.N. Fedotov, E.V. Trofimova, N.S. Zefirov, 2015, published in Zhurnal Organicheskoi Khimii, 2015, Vol. 51, No. 9,
pp. 1241–1255.
Hydrochloric Acid as an Efficient Catalyst for Intermolecular
Condensation of Alcohols. A Simple and Highly Efficient
Synthesis of Unsymmetrical Ethers from Benzylic
Alcohols and Alkanols
S. S. Mochalov, A. N. Fedotov, E. V. Trofimova, and N. S. Zefirov
Faculty of Chemistry, Moscow State University, Leninskie gory 1, Moscow, 119991 Russia
e-mail: fed@org.chem.msu.ru
Received July 7, 2015
Abstract—Benzylic alcohols and diarylmethanols with electron-donating substituents in the aromatic ring
reacted with aliphatic alcohols in the presence of a catalytic amount of HCl to give the corresponding alkyl
arylmethyl ethers. The reactivity of diarylmethanols in the intermolecular dehydration depended on the nature
of substituents in the aromatic rings and structure of aliphatic alcohol.
DOI: 10.1134/S107042801509002X
The problem of creating an ether bond in organic
molecules still remains important for organic synthesis
since the existing etherification methods are far from
being perfect. During the past 10–15 years, a large
number of publications appeared, which were con-
cerned with both improvement of classical methods
of synthesis of ethers (such as Williamson reaction,
intermolecular dehydration of alcohols, and catalytic
addition of alcohols to alkenes [1–4]) and development
of new synthetic approaches (e.g., reductive etherifica-
tion of aldehydes and ketones, nucleophilic exchange
in alkoxysilyl ethers, and selective reduction of the
carbonyl group in carboxylic acid esters [5–11]).
Among a wide variety of Brønsted acids, only those
having weakly nucleophilic anions were used to cata-
lyze intermolecular dehydration of alcohols. Therefore,
it is not surprising that there are no published data on
direct catalysis of etherification of alkanols by hydro-
halic acids. On the other hand, it is known [16] that
dilute aqueous HCl efficiently catalyzes replacement
of the hemiacetal hydroxy group in cyclic sugars by
methoxy under very mild conditions. The ease of this
reaction is generally rationalized by the ability of that
hydroxy group to take up a proton with subsequent
elimination of water to produce a stable and quite
reactive carbenium ion whose stability is determined
by positive mesomeric effect of the neighboring
oxygen atom.
Taking the above stated into account, we presumed
that all arylalkanols capable of forming stable carbe-
nium ions due to the presence of electron-donating
substituents could undergo mild etherification in the
presence of a catalytic amount of hydrochloric acid.
Examples of stable carbenium ions resembling those
derived from hemiacetals are benzyl cations generated
from alkoxy-substituted benzylic alcohols as a result of
acid-catalyzed elimination of the hydroxy group
(Scheme 1).
From the viewpoints of low-cost technology, atom
economy, and green chemistry principles, the most
promising is direct synthesis of symmetrical and
unsymmetrical ethers via acid-catalyzed condensation
of the corresponding alcohols, where the only by-prod-
uct is environmentally safe water. However, prelimi-
nary studies of etherification of alcohols by inter-
molecular dehydration in the presence of mineral acids
and other acid catalysts [1, 3, 12–15] showed that this
reaction is often accompanied by rearrangements of
alkyl groups and/or formation of alkenes. Never-
theless, as reported in [2, 4], Brønsted or Lewis acid-
catalyzed intermolecular dehydration of alcohols can
be accomplished with high chemoselectivity and high
yield of target ethers.
In this work we succeeded in demonstrating that, in
fact, benzyl alcohols having electron-donating groups
in the aromatic ring can be readily etherified under
1217

MOCHALOV et al.
1218
Scheme 1.
OH
OH
H+, –H2O
H2O, –H+
Me
Me
Me
Me
MeO
O
MeO
O
MeO
O
H+, –H2O
H2O, –H+
Me
Me
O
O
O
catalysis by HCl (Scheme 2, Table 1), the molar ratio
benzylic alcohol–alkanol–catalyst being 1:15:0.05.
The data in Table 1 clearly show different reactivities
of benzyl alcohols containing alkoxy (1c, 3a–3h, 5a,
5b) and other electron-donating groups (1b, 1d, 1e, 1f)
in the aromatic ring; the former are considerably more
reactive. This indicates only that the oxygen atom of
the alkoxy group in the para position of benzyl alcohol
is capable of stabilizing benzyl-type carbenium ions.
The reaction mixtures were kept for a long time with
a view to elucidating whether benzyl alcohols can be
etherified without additional energy expenditure. The
formation of unsymmetrical ethers can be considerably
accelerated by carrying out the reaction at elevated
temperature (in boiling alkanol; run nos. 9, 11, 14, 15).
Unlike HCl-catalyzed condensation of benzyl
alcohols 1c and 3a with methanol (run nos. 3, 16),
the corresponding methyl ethers were formed from
1-(4-methoxyphenyl)ethanol (1c) and 1,3-benzodioxol-
5-ylmethanol (an analog of 3a) in the presence of
a catalytic amount of NaHSO3 only on heating in
boiling methanol for 14 h (2c) or at 110°C for 1 h,
respectively, and in both cases, the yields of the target
methyl ethers did not exceed 87% [4].
Scheme 2.
R2
R2
R3
R3
AlkOH, HCl (5 mol %), 20°C
AlkOH, HCl (5 mol %), 20°C
AlkOH, HCl (5 mol %), 20°C
OH
OAlk
R1
R1
1a–1f
2a–2m
R2
R2
O
O
O
O
OH
OH
OAlk
R1
R
R1
3a–3j
4a–4t
R
O
O
O
O
OAlk
5a, 5b
6a–6d
1, R1 = R2 = R3 = H (a); R1 = H, R2 = R3 = Me (b); R2 = H, R3 = Me; R1 = 4-MeO (c), 4-t-Bu (d), 4-(1-methylcyclopropyl) (e),
3,4-(CH2)4 (f); 2, R1 = R2 = R3 = H, Alk = Et (a); R1 = H, R2 = R3 = Alk = Me (b); R1 = 4-MeO, R2 = H, R3 = Alk = Me (c); R1 =
4-MeO, R2 = H, R3 = Me, Alk = Et (d); R1 = 4-MeO, R2 = H, R3 = Me, Alk = i-Pr (e); R1 = 4-t-Bu, R2 = H, R3 = Alk = Me (f); R1 =
4-t-Bu, R2 = H, R3 = Me, Alk = Et (g); R1 = 4-t-Bu, R2 = H, R3 = Me, Alk = i-Pr (h); R1 = 4-(1-methylcyclopropyl), R2 = H, R3 =
Alk = Me (i); R1 = 4-(1-methylcyclopropyl), R2 = H, R3 = Me, Alk = i-Pr (j); R1 = 3,4-(CH2)4, R2 = H, R3 = Alk = Me (k); R1 =
3,4-(CH2)4, R2 = H, R3 = Me, Alk = Et (l); R1 = 3,4-(CH2)4, R2 = H, R3 = Me, Alk = i-Pr (m); 3, R1 = H, R2 = Me (a), Et (b), Pr (c),
i-Pr (d), Bu (e), cyclo-C3H5 (f); R1 = Br, R2 = cyclo-C3H5 (g); R1 = H, R2 = PhCH2 (h), BrCH2 (i); R1 = O2N, R2 = Et (j); 4, R1 = H,
R2 = Alk = Me (a); R1 = H, R2 = Me, Alk = Et (b); R1 = H, R2 = Me, Alk = i-Pr (c); R1 = H, R2 = Me, Alk = PhCH2 (d); R1 = H, R2 =
Et, Alk = Me (e); R1 = H, R2 = Alk = Et (f); R1 = H, R2 = Et, Alk = C5H11 (g); R1 = H, R2 = Pr, Alk = Et (h); R1 = H, R2 = i-Pr, Alk =
Me (i); R1 = H, R2 = i-Pr, Alk = Et (j); R1 = H, R2 = Bu, Alk = Me (k); R1 = H, R2 = Bu, Alk = Et (l); R1 = H, R2 = cyclo-C3H5, Alk =
Me (m); R1 = H, R2 = cyclo-C3H5, Alk = Et (n); R1 = Br, R2 = cyclo-C3H5, Alk = Me (o); R1 = Br, R2 = cyclo-C3H5, Alk = Et (p); R1 =
Br, R2 = cyclo-C3H5, Alk = i-Pr (q); R1 = H, R2 = PhCH2, Alk = Me (r); R1 = H, R2 = PhCH2, Alk = Et (s); R1 = H, R2 = PhCH2,
Alk = i-Pr (t); 5, R = Me (a), PhCH2 (b); 6, R = Alk = Me (a); R = PhCH2, Alk = Me (b), Et (c), i-Pr (d).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

HYDROCHLORIC ACID AS AN EFFICIENT CATALYST
1219
Table 1. Intermolecular etherification of benzyl alcohols with alkanols, catalyzed by HCl (molar ratio benzyl alcohol–
alkanol–HCl 1:15:0.05; 20°C)
Composition of the reaction mixture,a %
Run
no.
Reaction
time, h
Unsymmetrical
ether
Benzyl alcohol
Alkanol
unsymmetrical ether unreacted benzyl alcohol
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
1a
1b
1c
1c
1c
1d
1d
1d
1d
1e
1e
1f
EtOH
500
320
196
196
196
500
500
500
005b
320
005b
320
320
005b
007b
120
196
196
196
120
196
120
196
120
196
120
196
072
096
072
120
120
096
196
320
196
320
2a
2b
2c
2d
2e
2f
008
100
100
074
031
089
032
013
035
100
095
093
028
095
081
100
096
051
88
92
00
00
26
69
11
68
87
65
00
04
07
72
04
19
00
04
49
12
00
00
00
00
00
18
00
00
00
00
00
00
05
00
14
00
65
39
MeOH
MeOH
EtOH
i-PrOH
MeOH
EtOH
2g
2h
2h
2i
i-PrOH
i-PrOH
MeOH
i-PrOH
MeOH
EtOH
2j
2k
2l
1f
1f
EtOH
2l
1f
i-PrOH
MeOH
EtOH
2m
4a
4b
4c
4d
4e
4f
3a
3a
3a
3a
3b
3b
3b
3c
3d
3d
3e
3e
3f
i-PrOH
BnOH
MeOH
EtOH
100
100
100
100
100
082
100
100
100
100
100
100
095
100
086
100
035
061
AmOH
EtOH
4g
4h
4i
MeOH
EtOH
4j
MeOH
EtOH
4k
4l
MeOH
EtOH
4m
4n
4o
4p
4q
4r
4s
4s
4t
3f
3g
3g
3g
3h
3h
3h
3h
3h
MeOH
EtOH
i-PrOH
MeOH
EtOH
EtOH
i-PrOH
i-PrOH
4t
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

MOCHALOV et al.
1220
Table 1. (Contd.)
Composition of the reaction mixture,a %
Run
no.
Reaction
time, h
Unsymmetrical
ether
Benzyl alcohol
Alkanol
unsymmetrical ether unreacted benzyl alcohol
38
39
40
41
42
43
5a
5b
5b
5b
5b
5b
MeOH
MeOH
EtOH
120
120
196
500
196
500
6a
6b
6c
6c
6d
6d
100
100
031
071
015
035
00
00
69
28
85
65
EtOH
i-PrOH
i-PrOH
a
According to the 1H NMR data.
The reaction was carried out on heating under reflux.
b
It was also interesting to compare our results with
tion of benzyl alcohols involves intermediate forma-
tion of benzyl-type carbenium ions [4], the observed
dependence of the yield on the alkanol structure can be
rationalized only by steric factors.
those obtained in the acid-catalyzed addition of alco-
hols to terminal arylalkenes. Methyl and isopropyl
alcohols reacted with α-methylstyrene and 4-methoxy-
styrene in the presence of silica-supported KHSO4 to
afford methyl 2-phenylpropan-2-yl ether, 1-(4-me-
thoxyphenyl)ethyl methyl ether, and isopropyl
1-(4-methoxyphenyl)ethyl ether in 26, 25, and 11%
yield, respectively [11], whereas the major products
were the corresponding styrene dimers. As follows
from the data in Table 1 (run nos. 2, 3, 5), the synthesis
of the above listed ethers by HCl-catalyzed intermolec-
ular condensation of alcohols is much more efficient
than the reactions catalyzed by solid NaHSO3 [4] or
KHSO4/SiO2 [11].
It is important to note that the three-membered ring
in cyclopropylcarbinols 3f and 3g remained intact
under the etherification conditions (run nos. 28–32),
although isomerization of ion A (Scheme 3) might be
expected by analogy with the known transformation of
carbenium ion derived from cyclopropyl(phenyl)-
methanol under acidic conditions [17]. Insofar as
cyclopropyl(phenyl)methyl cation (analog of A) gen-
erated from cyclopropyl(phenyl)methanol by the
action of trifluoroacetic acid isomerizes by more than
40% into 1-phenylbut-1-en-4-yl cation (analog of B),
eventually yielding the corresponding trifluoroacetate
[17], the presence of fused 1,4-dioxine ring in mole-
cules 3f and 3g is likely to inhibit the isomerization
A → B due to significant contribution of mesomeric
structure A′ to the stabilization of ion A.
It was somewhat surprising that in all cases the
yield of unsymmetrical ether under standard conditions
tended to decrease in going from methanol to ethanol
and isopropyl alcohol. However, the yields in the reac-
tions with pentyl and benzyl alcohols approached those
in the etherification with methanol (run nos. 3, 19, 22,
24, 26). Analogous tendency was observed in [4] while
studying etherification of benzylic alcohol 1c with
primary and secondary alkanols. The latter ensured
a lower yield. Taking into consideration that etherifica-
It was found that benzylic alcohols like 3 having
strong electron-donating groups [3,4-(CH2)2O2] in the
benzene ring together with moderate electron-with-
drawing substituents in the side chain (R1 = H, R2 =
BrCH2) or strong electron-withdrawing substituents in
Scheme 3.
OH
H
H+
O
O
O
O
O
O
–H2O
X
X
X
3f, 3g
A
A'
O
O
O
O
Nu–
A
Nu
X
CH2
X
B
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

HYDROCHLORIC ACID AS AN EFFICIENT CATALYST
1221
Scheme 4.
Ar
Ar
AlkOH, HCl (5 mol %), 20°C
OH
OAlk
R1
R1
R2
R2
7a–7o
8a–8x
7, R1 = R2 = H, Ar = Ph (a); R1 = 3,4-(CH2)2O2, R2 = H, Ar = Ph (b), 4-MeC6H4 (c), 4-MeOC6H4 (d), 4-FC6H4 (e), 4-ClC6H4 (f),
3-NCC6H4 (g), 2-thienyl (h); R1 = 3,4-(MeO)2, R2 = H, Ar = 4-FC6H4 (i); R1 = 3,4-(CH2)2O2, Ar = Ph, R2 = Br (j), O2N (k); R1 =
3,4-(CH2)2O2, Ar = 4-MeC6H4, R2 = cyclopropylcarbonylamino (l), PhCH2C(O)NH (m), Ar = 4-ClC6H4, R2 = thiophen-
2-ylcarbonylamino (n); R1 = 3,4- (CH2)2O2, R2 = cyclopropylcarbonylamino, Ar = 3-FC6H4 (o); 8, R1 = R2 = H, Ar = Ph, Alk =
Me (a), Et (b); R1 = 3,4-(CH2)2O2, R2 = H, Ar = Ph, Alk = Me (c), Et (d), i-Pr (e); R1 = 3,4-(CH2)2O2, R2 = H, Ar = 4-MeC6H4, Alk =
Me (f), Et (g), i-Pr (h); R1 = 3,4-(CH2)2O2, R2 = H, Ar =4-MeOC6H4, Alk = Me (i), Et (j), i-Pr (k); R1 = 3,4-(CH2)2O2, R2 = H, Alk =
i-Pr, Ar = 4-FC6H4 (l); Alk = Et, 4-ClC6H4 (m), 3-NCC6H4 (n), 2-thienyl (o); R1 = 3,4-(MeO)2, R2 = H, Ar = 4-FC6H4, Alk = Me (p),
i-Pr (q); R1 = 3,4-(CH2)2O2, R2 = Br, Ar = Ph, Alk = Me (r), Et (s); R1 = 3,4-(CH2)2O2, R2 = O2N, Ar = Ph, Alk = Me (t); R1 =
3,4-(CH2)2O2, Ar = 4-MeC6H4, Alk = Et, R2 = cyclopropylcarbonylamino (u), PhCH2C(O)NH (v); R1 = 3,4-(CH2)2O2, R2 = thiophen-
2-ylcarbonylamino, Ar = 4-ClC6H4, Alk = Et (w); R1 = 3,4-(CH2)2O2, R2 = cyclopropylcarbonylamino, Ar = 3-FC6H4, Alk = Et (x).
the benzene ring (R1 = NO2, R2 = Et) failed to react
conversion of 7a into unsymmetrical ether was com-
plete (or almost complete) only at elevated temperature
(Table 2; run nos. 2, 4). This confirms once more the
crucial role of oxygen-containing substituents in the
aryl fragments in the stabilization of intermediate
benzyl and diphenylmethyl cations. The substituents in
the second benzene ring (not fused to 1,4-dioxine)
almost did not affect the reactivity of 2,3-dihydro-1,4-
benzodioxin-6-yl(phenyl)methanols 7c–7g, and the
yields of the corresponding unsymmetrical ethers in all
cases were fairly high (run nos. 8–16, 18, 19). On the
other hand, appreciable difference was observed in the
behavior of benzhydrol derivatives containing halogen
atoms in different aromatic fragments. The fluorine
and chlorine atoms insignificantly deactivated p-halo-
phenyl derivatives 7e, 7f, and 7i toward etherification
(run nos. 14, 15, 18, 19), whereas the bromine atom in
the benzodioxine fragment of 7j considerably reduced
its reactivity. The methylation of 7j under standard
conditions was characterized by a lower yield, while
its ethylation required elevated temperature (Tabl. 2;
with alkanols at 20°C under the given conditions. On
the other hand, the reactivity did not change upon
introduction of a bromine atom into the benzene ring
(cf. 3f and 3g; run nos. 30–32).
Unlike cross etherification of benzylic alcohols via
intermolecular dehydration, no data on analogous
transformations in the series of diphenylmethanols
(benzhydrols) have been reported so far. Only the
synthesis of symmetrical bis(diphenylmethyl) ether by
dehydration of benzhydrol in the presence of an equi-
molar amount of ZnI2 [18] or ZnCl2 [19] was de-
scribed. We have found that intermolecular etherifica-
tion of benzhydrols with alkanols is easy to accomplish
using a catalytic amount of HCl and that the reaction
occurs even more readily than in the series of α-alkyl-
benzyl alcohols (Scheme 4, Table 2).
As follows from the data in Table 2, unsubstituted
benzhydrol (7a) is much less reactive than diaryl-
methanols with alkoxy groups in the benzene rings; the
Scheme 5.
OH
OEt
Ar
H+, –H2O
O
O
O
O
O
O
EtOH
–H+
Ar
Ar
H2O, –H+
Path a
NHC(O)R
NHC(O)R
NHC(O)R
7l–7o
A
Ar
O
Ar
H
O
O
O
O
O
–H+
Path b
N
R
N
R
B
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

MOCHALOV et al.
1222
Table 2. Condensation of diarylmethanols with alkanols in the presence of HCl (molar ratio 7–8–HCl 1:15:0.05; 20°C)
Composition of the reaction mixture,a %
Run
no.
Reaction Unsymmetrical
Diarylmethanol Alkanol
time, h
ether
unsymmetrical ether
unreacted diarylmethanol
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
7a
7a
7a
7a
7b
7b
7b
7c
7c
7c
7d
7d
7d
7e
7f
MeOH
MeOH
EtOH
168
005b
400
008b
096
120
120
072
096
120
072
096
120
168
168
168
168
096
120
120
168
006b
008b
168
168
168
320
8a
8a
8b
8b
8c
8d
8e
8f
021
100
012
053
100
100
085
100
100
100
100
100
100
089
091
084
100
100
100
071
008
100
007
100
095
049
052
79
00
88
47
00
00
15
00
00
00
00
00
00
11
09
16
00
00
00
29
92
00
93
00
05
51
48
EtOH
MeOH
EtOH
i-PrOH
MeOH
EtOH
8g
8h
8i
i-PrOH
MeOH
EtOH
8j
i-PrOH
i-PrOH
EtOH
8k
8l
8m
8n
8o
8p
8q
8r
8s
7g
7h
7i
EtOH
EtOH
MeOH
i-PrOH
MeOH
EtOH
7i
7j
7j
7j
EtOH
8s
7k
7l
MeOH
EtOH
8t
8u
8v
8w
8x
7m
7n
7o
EtOH
EtOH
EtOH
a
According to the 1H NMR data.
The reaction was carried out on heating under reflux.
b
run nos. 20–22). Unlike 7j whose etherification with
alkanols was still feasible despite the presence of elec-
tron-withdrawing bromine atom in the benzodioxane
fragment (though under more severe conditions), nitro-
substituted benzhydrol failed to react with alkanols
even on prolonged heating.
successfully etherified with alcohols via acid-catalyzed
dehydration. The yields of unsymmetrical ethers in the
reactions of the examined benzhydrols with alkanols
almost did not depend on the latter (Table 2; run
nos. 3–9, 12, 13).
Insofar as the etherification of benzyl alcohols in-
volves formation of benzyl type cations [4], it seemed
important to examine etherification of benzhydrols
containing nucleophilic substituents in the ortho posi-
tion with a view to elucidating whether the reaction
It should be noted that the etherification of (2,3-di-
hydro-1,4-benzodioxin-6-yl)(thiophen-2-yl)methanol
(7h) was as ready as the reaction with 7b (run nos. 6,
17). This indicates that aryl(hetaryl)methanols can be
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

HYDROCHLORIC ACID AS AN EFFICIENT CATALYST
1223
would be complicated by participation of the internal
nucleophile in the stabilization of carbenium ion. It is
known that benzhydrols 7l–7o undergo cyclization to
1,3-benzoxazines with high yields by the action of
trifluoroacetic acid [20].
1-(2,3-Dihydro-1,4-benzodioxin-6-yl)butan-1-ol
(3c). Yield 81%, viscous oily material. H NMR spec-
1
trum (CDCl3), δ, ppm: 0.92 t (3H, CH3, J = 7.3 Hz),
1.28 m and 1.40 m (1H each, CH2CH2CH3), 1.61 m
and 1.73 m (1H each, CH2CH2CH3), 2.20 br.s (1H,
OH), 4.23 s (4H, OCH2CH2O), 4.53 t (1H, CHOH, J =
6.7 Hz), 6.78–6.87 m (3H, Harom). Found, %: C 69.06,
69.08; H 7.61, 7.71. C12H16O3. Calculated, %: C 69.21;
H 7.75.
Two paths of acid-catalyzed transformations of
ortho-acylamino-substituted benzhydrols 7l–7o are
theoretically possible, and both these involve carbe-
nium ion A as key intermediate (Scheme 5). Our
results showed that the HCl-catalyzed reaction of
7l–7o with ethanol follows only the intermolecular de-
hydration path (a) leading to the corresponding unsym-
metrical ethers (Table 2; run nos. 24–27). It is very
likely that under the given conditions the nucleo-
philicity of the oxygen atom of nonprotonated alkanol
is considerably higher than the nucleophilicity of the
amide oxygen atom, which prevents formation of
cyclic ions B and hence benzoxazines (path b).
1-(2,3-Dihydro-1,4-benzodioxin-6-yl)-2-methyl-
propan-1-ol (3d). Yield 74%, viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 0.77 d and 0.99 d
[3H each, CH(CH3)2, J = 6.6 Hz], 1.91 m [1H,
CH(CH3)2], 2.08 br.s (1H, OH), 4.22 s (4H,
OCH2CH2O), 4.31 m (1H, CHOH), 6.72–6.84 m (3H,
H
arom). Found, %: C 69.01, 69.11; H 7.69, 7.71.
C12H16O3. Calculated, %: C 69.21; H 7.75.
1-(2,3-Dihydro-1,4-benzodioxin-6-yl)pentan-1-ol
1
Thus, we have shown for the first time that chemo-
selective intermolecular condensation of benzyl alco-
hols and diarylmethanols with alkanols can be accom-
plished under catalysis by hydrochloric acid.
(3e). Yield 84%, viscous oily material. H NMR spec-
trum (CDCl3), δ, ppm: 0.79 t (3H, CH3, J = 6.6 Hz),
1.11 m (1H) and 1.25 m (3H, CH2CH2CH2CH3),
1.56 m and 1.68 m (1H each, CH2CH2CH2CH3),
1.96 br.s (1H, OH), 4.25 s (4H, OCH2CH2O), 4.51 t
4
EXPERIMENTAL
(1H, CHOH, J = 5.9 Hz), 6.67 d.d (1H, 7-H, J = 2.1,
3J = 8.2 Hz), 6.72 d (1H, 8-H, 3J = 8.2 Hz), 6.77 d (1H,
1
The H NMR spectra were recorded on a Varian
4
5-H, J = 2.1 Hz). Found, %: C 70.06, 70.11; H 8.08,
VXR-400 spectrometer at 400 MHz; the chemical
shifts were measured relative to the residual proton
signal of the deuterated solvent. The elemental anal-
yses were obtained on a Varian-11 CHN analyzer. The
melting points were determined on an Electrothermal
Digital Melting Point Apparatus (model 1A9100). The
products were isolated by distillation (in large-scale
syntheses) or by chromatography on Al2O3 (Brock-
mann activity grade II) or silica gel (40–100 μm) using
diethyl ether–hexane mixtures with different ratios.
8.10. C13H18O3. Calculated, %: C 70.24; H 8.16.
Cyclopropyl(2,3-dihydro-1,4-benzodioxin-6-yl)-
methanol (3f). Yield 69%, viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 0.37 m, 0.46 m,
0.56 m, 0.63 m, and 1.79 m (1H each, C3H5); 2.01 br.s
(1H, OH), 3.91 d (1H, CHOH, J = 6.6 Hz), 4.27 m
(4H, OCH2CH2O), 6.87 d (1H, 8-H, J = 8.0 Hz),
4
3
6.91 d.d (1H, 7-H, J = 2.0, J = 8.0 Hz), 6.97 d (1H,
4
5-H, J = 2.0 Hz). Found, %: C 69.67, 69.81; H 6.77,
6.78. C12H14O3. Calculated, %: C 69.88; H 6.84.
Initial benzyl alcohols (except for 1a and 1b) and
benzhydrols were synthesized by reduction of the cor-
responding alkyl aryl ketones and benzophenones with
sodium tetrahydridoborate according to [20]. The
physicochemical characteristics of 1d [21], 1f [22], 3a,
3b, 3j, 7b [21], 7l, and 7o [23] were consistent with
published data.
(7-Bromo-2,3-dihydro-1,4-benzodioxin-6-yl)-
cyclopropylmethanol (3g). Yield 86%, viscous oily
1
material. H NMR spectrum (CD2Cl2), δ, ppm: 0.48 m
(3H), 0.61 m (1H), and 1.23 m (1H) (C3H5); 2.22 br.s
(1H, OH), 4.27 s (4H, OCH2CH2O), 4.51 d (1H,
CHOH, J = 4.8 Hz), 7.07 s (1H, 5-H), 7.13 s (1H,
8-H). Found, %: C 50.34, 50.41; H 4.31, 4.41.
C12H13BrO3. Calculated, %: C 50.55; H 4.59.
1-[4-(1-Methylcyclopropyl)phenyl]ethanol (1e).
1
Yield 79%, viscous oily material. H NMR spectrum
1-(2,3-Dihydro-1,4-benzodioxin-6-yl)-2-phenyl-
ethanol (3h). Yield 82%, viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 2.19 br.s (1H,
OH), 3.01 m (2H, CH2Ph), 4.25 s (4H, OCH2CH2O),
4.79 t (1H, CHOH, J = 6.8 Hz), 6.83 d.d (1H, 7-H,
(CDCl3), δ, ppm: 0.77 m and 0.89 m (2H each,
CH2CH2), 1.44 s (3H, CH3), 1.51 d (3H, CHCH3, J =
6.2 Hz), 2.19 br.s (1H, OH), 4.86 q (1H, CHCH3, J =
6.2 Hz), 7.26 d (2H, o-H, J = 8.1 Hz), 7.31 d (2H,
m-H, J = 8.1 Hz). Found, %: C 81.52, 81.63; H 9.03,
9.11. C12H16O. Calculated, %: C 81.77; H 9.15.
3
3
4J = 1.6, J = 8.0 Hz), 6.86 d (1H, 8-H, J = 8.0 Hz),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

MOCHALOV et al.
1224
4
6.93 d (1H, 5-H, J = 1.6 Hz), 7.23 d (2H, 2′-H, 6′-H,
J = 7.8 Hz), 7.28 m (1H, 4′-H), 7.33 t (2H, 3′-H, 5′-H,
3J = 8.0 Hz). Found, %: C 74.77, 74.85; H 6.11, 6.19.
C16H16O3. Calculated, %: C 74.98; H 6.29.
(2,3-Dihydro-1,4-benzodioxin-6-yl)(4-fluoro-
phenyl)methanol (7e). Yield 89%, viscous oily mate-
rial. 1H NMR spectrum (CDCl3), δ, ppm: 2.28 br.s (1H,
OH), 4.24 s (4H, OCH2CH2O), 5.72 s (1H, CHOH),
6.83 m (2H, 7-H, 8-H), 6.83 m (1H, 5-H), 7.03 t (2H,
2-Bromo-1-(2,3-dihydro-1,4-benzodioxin-6-yl)-
ethanol (3i). Yield 76%, viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 2.79 br.s (1H,
OH), 3.53 m (2H, CH2Br), 4.25 s (4H, OCH2CH2O),
4.81 m (1H, CHOH), 6.85 m (2H, 7-H, 8-H), 6.91 m
(1H, 5-H). Found, %: C 46.17, 46.22; H 4.11, 4.21.
C10H11BrO3. Calculated, %: C 46.36; H 4.28.
3
3′-H, 5′-H, JHH = 8.2, JHF = 8.2 Hz), 7.34 d.d (2H,
3
2′-H, 6′-H, JHH = 8.2, JHF = 5.4 Hz). Found, %:
C 68.93, 69.06; H 4.88, 4.94. C15H13FO3. Calculated,
%: C 69.22; H 5.03.
(4-Chlorophenyl)(2,3-dihydro-1,4-benzodioxin-
6-yl)methanol (7f). Yield 87%, viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 2.51 br.s (1H,
OH), 4.23 s (4H, OCH2CH23O), 5.68 s (1H, CHOH),
1-(3,4-Dihydro-2H-1,5-benzodioxepin-7-yl)-
ethanol (5a). Yield 91%, viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 1.46 d (3H, CH3,
J = 6.5 Hz), 1.98 br.s (1H, OH), 2.19 quint (2H,
O C H 2 C H 2 C H 2 O , J = 5 . 6 H z ) , 4 . 2 0 q ( 4 H,
OCH2CH2CH2O, J = 5.6 Hz), 4.79 q (1H, CHCH3, J =
4
6.81 d.d (1H, 7-H, J = 1.8, J = 8.2 Hz), 6.84 d (1H,
8-H, 3J = 8.2 Hz), 6.85 d (1H, 5-H, 4J = 1.8 Hz), 7.30 s
(4H, Harom). Found, %: C 64.88, 64.96; H 4.61, 4.63.
C15H13ClO3. Calculated, %: C 65.11; H 4.73.
4
3
3-[(2,3-Dihydro-1,4-benzodioxin-6-yl)(hydroxy)-
methyl]benzonitrile (7g). Yield 72%, viscous oily
material. 1H NMR spectrum (CDCl3), δ, ppm: 2.48 br.s
(1H, OH), 4.25 s (4H, OCH2CH2O), 5.74 s (1H,
CHOH), 6.82–6.86 m (3H, 5-H, 7-H, 8-H), 7.43 t (1H,
5′-H, J = 7.8 Hz), 7.54 d (1H, 6′-H, J = 7.8 Hz), 7.62 d
(1H, 4′-H, J = 7.8 Hz), 7.69 s (1H, 2′-H). Found, %:
C 71.82, 71.76; H 4.78, 4.81; N 5.01, 5.09. C16H13NO3.
Calculated, %: C 71.90; H 4.90; N 5.24.
6.5 Hz), 6.92 d.d (1H, 6-H, J = 1.8, J = 8.2 Hz),
3
4
6.95 d (1H, 5-H, J = 8.2 Hz), 6.99 d (1H, 2-H, J =
1.8 Hz). Found, %: C 67.88, 67.93; H 7.15, 7.21.
C11H14O3. Calculated, %: C 68.02; H 7.26.
1-(3,4-Dihydro-2H-1,5-benzodioxepin-7-yl)-
2-phenylethanol (5b). Yield 83%, viscous oily
material. 1H NMR spectrum (CDCl3), δ, ppm: 2.12 br.s
(1H, OH), 2.20 m (2H, OCH2CH2CH2O), 3.01 m (2H,
CH2Ph), 4.22 m (4H, OCH2CH2CH2O), 4.81 d.d (1H,
(2,3-Dihydro-1,4-benzodioxin-6-yl)(thiophen-2-
yl)methanol (7h). Yield 78%, viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 2.68 s (1H, OH),
4.24 s (4H, OCH2CH2O), 5.93 s (1H, CHOH), 6.86 d
4
CHCH2Ph, J = 5.5, 8.5 Hz), 6.93 d.d (1H, 6-H, J =
2.0, 3J = 8.0 Hz), 6.97 d (1H, 5-H, 3J = 8.0 Hz), 7.02 d
4
(1H, 2-H, J = 2.0 Hz), 7.22 m (2H, 2′-H, 6′-H),
7.26 m (1H, 4′-H), 7.33 m (2H, 3′-H, 5′-H). Found, %:
C 75.36, 75.46; H 6.61, 6.65. C17H18O3. Calculated, %:
C 75.53; H 6.71.
3
(1H, 8-H, J = 8.1 Hz), 6.88–6.97 m (4H, Harom),
4
7.26 d (1H, 5-H, J = 2.4 Hz). Found, %: C 62.66,
62.71; H 4.71, 4.78. C13H12O3S. Calculated, %:
C 62.88; H 4.87.
(2,3-Dihydro-1,4-benzodioxin-6-yl)(4-methyl-
phenyl)methanol (7c). Yield 79%, viscous oily mate-
rial. H NMR spectrum (CDCl3), δ, ppm: 2.34–
(3,4-Dimethoxyphenyl)(4-fluorophenyl)methanol
(7i). Yield 88%, viscous oily material. H NMR spec-
1
1
2.40 br.s (4H, CH3, OH), 4.23 s (4H, OCH2CH2O),
5.71 s (1H, CHOH), 6.84 m (2H, 7-H, 8-H), 6.90 br.s
(1H, 5-H), 7.15 d (2H, 3′-H, 5′-H, J = 7.8 Hz), 7.26 d
(2H, 2′-H, 6′-H, J = 7.8 Hz). Found, %: C 74.74,
74.82; H 6.14, 6.21. C16H16O3. Calculated, %: C 74.98;
H 6.29.
trum (CDCl3), δ, ppm: 2.61 br.s (1H, OH), 3.86 s (6H,
3
OCH3), 5.73 s (1H, CHOH), 6.36 d (1H, 5-H, J =
4
3
8.2 Hz), 6.40 d.d (1H, 6-H, J = 1.8, J = 8.2 Hz),
4
6.49 d (1H, 2-H, J = 1.8 Hz), 6.53 t (2H, 3′-H, 5′-H,
3JHH = 8.2, JHF = 8.2 Hz ), 6.90 d.d (2H, 2′-H, 6′-H,
3JHH = 8.2, JHF = 6.0 Hz). Found, %: C 68.51, 68.62;
H 5.58, 5.62. C15H15FO3. Calculated, %: C 68.69;
H 5.76.
(2,3-Dihydro-1,4-benzodioxin-6-yl)(4-methoxy-
phenyl)methanol (7d). Yield 92%, viscous oily
material. 1H NMR spectrum (CDCl3), δ, ppm: 2.35 br.s
(1H, OH), 3. 81 s (3H, OCH3), 4. 23 s (4H,
OCH2CH2O), 5.69 s (1H, CHOH), 6.82–6.89 m (5H,
Harom), 7.29 d (2H, 2′-H, 6′-H, J = 8.4 Hz), Found, %:
C 70.22, 70.36; H 5.78, 5.85. C16H16O4. Calculated, %:
C 70.57; H 5.92.
(7-Bromo-2,3-dihydro-1,4-benzodioxin-6-yl)-
(phenyl)methanol (7j). Yield 95%, viscous oily mate-
rial. 1H NMR spectrum (CDCl3) δ, ppm: 2.48 br.s (1H,
OH), 4.22 s (4H, OCH2CH2O), 6.09 s (1H, CHOH),
7.05 s and 7.07 s (1H each, 5-H, 8-H), 7.30 m (1H,
4′-H), 7.35 t (2H, 3′-H, 5′-H, 3J = 7.8 Hz), 7.43 d (2H,
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HYDROCHLORIC ACID AS AN EFFICIENT CATALYST
1225
3
2′-H, 6′-H, J = 7.8 Hz). Found, %: C 55.88, 55.95;
1-Methoxy-4-(1-methoxyethyl)benzene (2c).
bp 122–123°C (20 mm), nD20 = 1.5104. H NMR spec-
1
H 3.96, 4.01. C15H13BrO3. Calculated, %: C 56.10;
H 4.08.
trum (CDCl3), δ, ppm: 1.41 d (3H, CHCH3, J =
6.2 Hz), 3.17 s (3H, CHOCH3), 3.78 s (3H, OCH3),
4.21 q (1H, CHOCH3, J = 6.2 Hz), 6.84 d (2H, 3-H,
5-H, J = 8.2 Hz), 7.19 d (2H, 2-H, 6-H, J = 8.2 Hz).
Found, %: C 72.01, 72.11; H 8.31, 8.36. C10H14O2.
Calculated, %: C 72.26; H 8.49.
(7-Nitro-2,3-dihydro-1,4-benzodioxin-6-yl)-
(phenyl)methanol (7k). Yield 77%, viscous oily mate-
rial. 1H NMR spectrum (CDCl3), δ, ppm: 3.05 br.s (1H,
OH), 4.29 m and 4.34 m (2H each, OCH2CH2O),
6.41 s (1H, CHOH), 7.19 s (1H, 6-H), 7.26–7.34 m
(5H, Harom), 7.65 s (1H, 3′-H). Found, %: C 62.51,
62.62; H 4.38, 4.47; N 4.71, 4.73. C15H13NO5. Cal-
culated, %: C 62.72; H 4.56; N 4.88.
1-tert-Butyl-4-(1-ethoxyethyl)benzene (2g).
bp 141–142°C (21 mm), nD20 = 1.5004. H NMR spec-
1
trum (CDCl3), δ, ppm: 1.21 t (3H, CH3CH2O, J =
6.9 Hz), 1.37 s [9H, C(CH3)3], 1.48 d (3H, CH3CH, J =
6.3 Hz), 3.42 q (2H, OCH2CH3, J = 6.9 Hz), 4.46 q
(1H, CH3CH, J = 6.3 Hz), 7.28 d (2H, Harom, J =
8.2 Hz), 7.39 d (2H, Harom, J = 8.2 Hz). Found, %:
C 81.27, 81.42; H 10.56, 10.63. C14H22O. Calculated,
%: C 81.50; H 10.74.
N-{7-[(Hydroxy)(4-methylphenyl)methyl]-2,3-di-
hydro-1,4-benzodioxin-6-yl}phenylacetamide (7m).
Yield 79%, mp 151–152°C (from EtOH). H NMR
1
spectrum (DMSO-d6), δ, ppm: 2.25 s (3H, CH3), 3.54 s
(2H, CH2Ph), 4.18 s (4H, OCH2CH2O), 5.71 d (1H,
OH, J = 3.3 Hz), 5.97 d (1H, CHOH, J = 3.3 Hz),
6.82 s (1H, 5-H), 7.04 s (4H, 2′-H, 3′-H, 5′-H, 6′-H),
7.08 s (1H, 8-H), 7.24 m (3H, Harom), 7.31 m (2H,
arom), 9.35 s (1H, NH). Found, %: C 73.88, 73.96;
H 5.81, 5.83; N 3.39, 3.48. C24H23NO4. Calculated, %:
C 74.02; H 5.95; N 3.60.
1-(1-Methoxyethyl)-4-(1-methylcyclopropyl)-
benzene (2i). Viscous oily material. 1H NMR spectrum
(CDCl3), δ, ppm: 0.77 m and 0.91 m (2H each,
CH2CH2), 1.45 s (3H, CH3), 1.47 d (3H, CH3CH, J =
6.6 Hz), 3.25 s (3H, OCH3), 4.31 q (1H, CH3CH,
J = 6.6 Hz), 7.26 s (4H, Harom). Found, %: C 81.88,
81.92; H 9.36, 9.45. C13H18O. Calculated, %: C 82.06;
H 9.53.
H
N-{7-[(4-Chlorophenyl)(hydroxy)methyl]-2,3-di-
hydro-1,4-benzodioxin-6-yl}thiophene-2-carbox-
amide (7n). Yield 83%, mp 149–150°C (from EtOH).
1H NMR spectrum (DMSO-d6), δ, ppm: 4.24 s (4H,
OCH2CH2O), 5.85 d (1H, OH, J = 3.8 Hz), 6.51 d (1H,
CHOH, J = 3.8 Hz), 6.88 s (1H, 5-H), 7.27 d (2H,
3′-H, 5′-H, J = 8.0 Hz), 7.30 d (2H, 2′-H, 6′-H, J =
8.0 Hz), 7.21 m (2H, 8-H, 4″-H), 7.71 m (1H, 5″-H),
7.83 d.d (1H, 3″-H, J = 0.8, J = 4.8 Hz), 10.01 s
(1H, NH). Found, %: C 59.59, 59.64; H 3.86, 3.92;
N 3.26, 3.33. C20H16ClNO4S. Calculated, %: C 59.77;
H 4.01; N 3.49.
1-(1-Isopropoxyethyl)-4-(1-methylcyclopropyl)-
benzene (2j). Viscous oily material. 1H NMR spectrum
(CDCl3), δ, ppm: 0.76 m and 0.90 m (2H each,
CH2CH2), 1.14 d and 1.18 d [3H each, CH(CH3)2, J =
6.2 Hz], 1.43 d (3H, CH3CH, J = 7.4 Hz), 1.45 s (3H,
CH3), 3.53 sept [1H, CH(CH3)2, J = 6.2 Hz], 4.54 q
(1H, OCHCH3, J = 7.4 Hz), 7.23–7.28 m (4H, Harom).
Found, %: C 82.28, 82.41; H 9.98, 10.07. C15H22O.
Calculated, %: C 82.52; H 10.15.
4
3
General procedure for etherification of benzyl
alcohols and diarylmethanols. Benzyl alcohol or
diarylmethanol, 0.1 mol, was dissolved in 1.5 mol of
the corresponding alkanol, 1.8 mL (~5 mmol) of
10% aqueous HCl was added, and the mixture was
kept at 20°C (or heated) as indicated in Tables 1 and 2.
The mixture was poured into 250 mL of cold water and
extracted with diethyl ether (2×50 mL), the extract
was dried over MgSO4 and evaporated, and the residue
was distilled or recrystallized from appropriate solvent.
In micro syntheses, the products were isolated by
chromatography on Al2O3 or SiO2.
6-(1-Methoxyethyl)-1,2,3,4-tetrahydronaphtha-
lene (2k). bp 158–159°C (19 mm), nD20 = 1.5275.
1H NMR spectrum (CDCl3), δ, ppm: 1.48 d (3H,
CHCH3, J = 6.2 Hz), 1.66 m (4H, 2-H, 3-H), 2.82 m
(4H, 1-H, 4-H), 3.28 s (3H, OCH3), 4.24 q (1H,
CHCH3, J = 6.2 Hz), 7.06–7.10 m (3H, 5-H, 7-H,
8-H). Found, %: C 81.81, 81.92; H 9.38, 9.42.
C13H18O. Calculated, %: C 82.06; H 9.53.
6-(1-Ethoxyethyl)-1,2,3,4-tetrahydronaphthalene
1
(2l). Viscous oily material. H NMR spectrum
(CDCl3), δ, ppm: 1.21 t (3H, OCH2CH3, J = 7.2 Hz),
1.45 d (3H, CHCH3, J = 6.2 Hz), 1.83 m (4H, 2-H,
3-H), 2.79 m (4H, 1-H, 4-H), 3.38 m (2H, OCH2CH3),
4.36 q (1H, CHCH3, J = 6.2 Hz), 7.03 s (1H, Harom),
7.07 s (2H, Harom). Found, %: C 82.04, 82.16; H 9.71,
9.79. C14H20O. Calculated, %: C 82.30; H 9.87.
The physicochemical characteristics of ethers 2a
[8], 2b [11], 2d [24], 2e [4], 2f [25], 2h [26], and 4f
[21] were consistent with published data. The yields
are given in Tables 1 and 2.
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MOCHALOV et al.
1226
C 68.95, 69.06; H 7.58, 7.64. C12H16O3. Calculated, %:
C 69.21; H 7.75.
6-(1-Isopropoxyethyl)-1,2,3,4-tetrahydronaph-
thalene (2m). Viscous oily material. H NMR spec-
1
trum (CDCl3), δ, ppm: 1.17 d and 1.21 d [(3H each,
CH(CH3)2, J = 7.3 Hz], 1.45 d (3H, CHCH3, J =
6.3 Hz), 1.85 m (4H, 2-H, 3-H), 2.82 m (4H, 1-H,
4-H), 3.57 s [(1H, CH(CH3)2], 4.53 q (1H, CHCH3, J =
6.3 Hz), 7.07–7.11 m (3H, Harom). Found, %: C 82.24,
82.36; H 9.94, 10.03. C15H22O. Calculated, %:
C 82.52; H 10.15.
6-[1-(Pentyloxy)propyl]-2,3-dihydro-1,4-benzo-
dioxine (4g). Viscous oily material. 1H NMR spectrum
(CDCl3), δ, ppm: 0.87 t [3H, (CH2)4CH3, J = 6.5 Hz)],
0.89 t (3H, CHCH2CH3, J = 6.5 Hz), 1.31 m (4H,
CH2CH2CH3), 1.56 m (2H, OCH2CH2), 1.58 m and
1.62 m (1H each, CHCH2CH3), 3.23 m and 3.32 m
(1H each, OCH2CH2CH2), 3.99 t (1H, CHCH2CH3,
J = 5.6 Hz), 4.25 s (4H, OCH2CH2O), 6.74 d.d (1H,
6-(1-Methoxyethyl)-2,3-dihydro-1,4-benzodioxine
4
3
4
1
7-H, J = 2.0, J = 8.2 Hz), 6.81 d (1H, 5-H, J =
(4a). bp 164–165°C (31 mm). H NMR spectrum
3
2.0 Hz), 6.83 d (1H, 8-H, J = 8.2 Hz). Found, %:
(CDCl3), δ, ppm: 1.36 d (3H, CHCH3, J = 6.2 Hz),
3.18 s (3H, OCH3), 4.18 q (1H, CHCH3, J = 6.2 Hz),
C 72.48, 72.57; H 8.98, 9.03. C16H24O3. Calculated, %:
C 72.69; H 9.15.
4
4.25 s (4H, OCH2CH2O), 6.75 d.d (1H, 7-H, J = 2.0,
3J = 8.3 Hz), 6.79 d (1H, 5-H, 4J = 2.0 Hz), 6.80 d (1H,
6-(1-Ethoxybutyl)-2,3-dihydro-1,4-benzodioxine
1
3
(4h). Viscous oily material. H NMR spectrum
8-H, J = 8.3 Hz). Found, %: C 67.81, 67.91; H 7.07,
(CDCl3), δ, ppm: 0.90 t (3H, CH2CH2CH3, J = 7.2 Hz),
1.17 t (3H, OCH2CH3, J = 6.3 Hz), 1.28 m and 1.40 m
(1H each, CH2CH2CH3), 1.57 m and 1.76 m (1H each,
CHCH2), 3.29 m (1H) and 3.37 m (1H each,
OCH2CH3), 4.09 t (1H, CHCH2, J = 6.0 Hz), 4.25 s
7.14. C11H14O3. Calculated, %: C 68.02; H 7.26.
6-(1-Ethoxyethyl)-2,3-dihydro-1,4-benzodioxine
1
(4b). bp 168–169°C (20 mm). H NMR spectrum
(CDCl3), δ, ppm: 1.18 t (3H, OCH2CH3, J = 7.4 Hz),
1.41 d (3H, CHCH3, J = 6.2 Hz), 3.35 m (2H,
OCH2CH3), 4.25 s (4H, OCH2CH2O), 4.31 q (1H,
CHCH3, J = 6.2 Hz), 6.79–6.85 m (3H, Harom). Found,
%: C 68.96, 69.09; H 7.56, 7.64. C12H16O3. Calculated,
%: C 69.21; H 7.75.
3
(4H, OCH2CH2O), 6.76 d (1H, 7-H, J = 8.2 Hz),
6.82 s (1H, 5-H), 6.84 d (1H, 8-H, 3J = 8.2 Hz). Found,
%: C 70.89, 70.96; H 8.31, 8.38. C14H20O3. Calculated,
%: C 71.16; H 8.53.
6-(1-Methoxy-2-methylpropyl)-2,3-dihydro-1,4-
benzodioxine (4i). bp 171–172°C (28 mm), nD20
=
6-(1-Isopropoxyethyl)-2,3-dihydro-1,4-benzo-
dioxine (4c). Viscous oily material. 1H NMR spectrum
(CD2Cl2), δ, ppm: 1.10 d and 1.15 d [3H each,
CH(CH3)2, J = 6.0 Hz], 1.36 d (3H, CHCH3, J =
6.5 Hz), 3.52 sept [1H, CH(CH3)2], 4.26 s (4H,
OCH2CH2O), 4.45 q (1H, CHCH3, J = 6.5 Hz), 6.82–
6.86 m (3H, Harom). Found, %: C 70.01, 70.12; H 8.01,
8.08. C13H18O3. Calculated, %: C 70.24; H 8.16.
1
1.5268. H NMR spectrum (CDCl3), δ, ppm: 0.73 d
and 0.99 d [3H, CH(CH3)2, J = 6.4 Hz], 1.86 m [1H,
CH(CH3)2], 3.18 s (3H, OCH3), 3.63 d (1H, CHOCH3,
J = 6.8 Hz), 4.25 s (4H, OCH2CH2O), 6.71 d.d (1H,
4
3
4
7-H, J = 1.8, J = 8.2 Hz), 6.77 d (1H, 5-H, J =
3
1.8 Hz), 6.82 d (1H, 8-H, J = 8.2 Hz). Found, %:
C 70.01, 70.12; H 7.98, 8.03. C13H18O3. Calculated, %:
C 70.24; H 8.16.
6-[1-(Benzyloxy)ethyl]-2,3-dihydro-1,4-benzo-
dioxine (4d). Viscous oily material. 1H NMR spectrum
(CDCl3), δ, ppm: 1.50 d (3H, CHCH3, J = 5.6 Hz),
4.30 s (4H, OCH2CH2O), 4.34 d and 4.51 d (1H each,
CH2Ph, J = 12.1 Hz), 4.44 q (1H, CHCH3, J = 5.6 Hz),
6-(1-Ethoxy-2-methylpropyl)-2,3-dihydro-1,4-
benzodioxine (4j). bp 177–178°C (24 mm), nD20
=
1
1.5256. H NMR spectrum (CDCl3), δ, ppm: 0.74 d
and 1.01 d [3H each, CH(CH3)2, J = 6.6 Hz], 1.17 t
(3H, OCH2CH3, J = 7.2 Hz), 1.88 m [1H, CH(CH3)2],
3.26 m and 3.38 m (1H each, OCH2CH3), 3.74 d (1H,
CHOCH2CH3, J = 7.4 Hz), 4.26 s (4H, OCH2CH2O),
4
3
6.88 d.d (1H, 7-H, J = 1.8, J = 8.1 Hz), 6.92 d (1H,
3
8-H, J = 8.1 Hz), 6.95 d (1H, 5-H, J = 1.8 Hz), 7.30–
7.37 m (5H, Ph). Found, %: C 75.39, 75.44; H 6.53,
6.58. C17H18O3. Calculated, %: C 75.53; H 6.71.
4
3
6.73 d.d (1H, 7-H, J = 1.6, J = 8.0 Hz), 6.80 d (1H,
4
3
5-H, J = 1.6 Hz), 6.83 d (1H, 8-H, J = 8.0 Hz).
Found, %: C 70.92, 71.03; H 8.32, 8.41. C14H20O3.
Calculated, %: C 71.16; H 8.53.
6-(1-Methoxypropyl)-2,3-dihydro-1,4-benzodiox-
1
ine (4e). Viscous oily material. H NMR spectrum
(CDCl3), δ, ppm: 0.86 t (3H, CH2CH3, J = 7.6 Hz),
1.65 m and 1.79 m (1H each, CH2CH3), 3.20 s (3H,
OCH3), 3.91 t (1H, CHCH2, J = 5.4 Hz), 4.26 s (4H,
6-(1-Methoxypentyl)-2,3-dihydro-1,4-benzodiox-
1
ine (4k). bp 189–190°C (26 mm). H NMR spectrum
3
OCH2CH2O), 6.76 d (1H, 7-H, J = 8.2 Hz), 6.81 s
(CDCl3), δ, ppm: 0.87 t [3H, (CH2)3CH3, J = 6.4 Hz],
1.30 m (1H) and 1.32 m (3H, CH2CH2CH2CH3),
3
(1H, 5-H), 6.84 d (1H, 8-H, J = 8.2 Hz). Found, %:
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

HYDROCHLORIC ACID AS AN EFFICIENT CATALYST
1227
1.61 m and 1.74 m (1H each, CH2CH2CH2CH3), 3.19 s
(3H, OCH3), 3.97 t (1H, CHOCH3, J = 6.4 Hz), 4.25 s
4.24 s (4H, OCH2CH2O), 6.97 s and 7.00 s (1H each,
5-H, 8-H). Found, %: C 53.36, 53.48; H 5.35, 5.39.
C14H17BrO3. Calculated, %: C 53.69; H 5.47.
4
3
(4H, OCH2CH2O), 6.75 d.d (1H, 7-H, J = 1.9, J =
4
8.2 Hz), 6.81 d (1H, 5-H, J = 1.9 Hz), 6.83 d (1H,
6-Bromo-7-[cyclopropyl(isopropoxy)methyl]-
3
8-H, J = 8.2 Hz). Found, %: C 71.02, 71.11; H 8.36,
2,3-dihydro-1,4-benzodioxine (4q). Viscous oily
1
8.46. C14H20O3. Calculated, %: C 71.16; H 8.53.
material. H NMR spectrum (CDCl3), δ, ppm: 0.38 m
6-(1-Ethoxypentyl)-2,3-dihydro-1,4-benzodioxine
(2H), 0.48 m (2H), and 1.10 m (1H) (cyclopropane);
1.08 d and 1.14 d [3H each, CH(CH3)2, J = 6.2 Hz],
3.41 sept [1H, CH(CH3)2], 4.25 s (4H, OCH2CH2O),
4.29 d [1H, CHOCH(CH3)2, J = 6.3 Hz], 6.99 s and
7.00 s (1H each, 5-H, 8-H). Found, %: C 54.81, 54.92;
H 5.64, 5.75. C15H19BrO3. Calculated, %: C 55.06;
H 5.85.
(4l). bp 186–187°C (20 mm), nD20 = 1.5136. H NMR
1
spectrum (CDCl3), δ, ppm: 0.89 t [3H, (CH2)3CH3, J =
7.0 Hz], 1.18 t (3H, OCH2CH3, J = 6.8 Hz), 1.20–
1.34 m (4H, CH2CH2CH2CH3), 1.59 m and 1.78 m
(1H each, CH2CH2CH2CH3), 3.29 m and 3.38 m
(1H each, OCH2CH3), 4.08 t (1H, CHOCH2CH3, J =
6.8 Hz), 4.26 s (4H, OCH2CH2O), 6.77 d.d (1H, 7-H,
6-(1-Methoxy-2-phenylethyl)-2,3-dihydro-1,4-
3
4
4J = 2.1, J = 8.3 Hz), 6.83 d (1H, 5-H, J = 2.1 Hz),
1
benzodioxine (4r). Viscous oily material. H NMR
3
6.84 d (1H, 8-H, J = 8.3 Hz). Found, %: C 71.72,
spectrum (CDCl3), δ, ppm: 2.89 d.d (1H, J = 5.6,
13.9 Hz) and 3.09 d.d (1H, J = 7.8, 13.9 Hz) (CH2Ph),
3.19 s (3H, OCH3), 4.23 d.d (1H, CHCH2Ph, J = 5.6,
7.8 Hz), 4.27 s (4H, OCH2CH2O), 6.71 d.d (1H, 7-H,
71.83; H 8.68, 8.77. C15H22O3. Calculated, %: C 71.97;
H 8.86.
6-[Cyclopropyl(methoxy)methyl]-2,3-dihydro-
1,4-benzodioxine (4m). Viscous oily material.
1H NMR spectrum (CD2Cl2), δ, ppm: 0.25 m (1H),
0.44 m (2H), 0.62 m (1H), and 1.12 m (1H) (cyclo-
propane); 3.23 s (3H, OCH3), 3.44 d (1H, CHCH3, J =
6.1 Hz), 4.28 s (4H, OCH2CH2O), 6.81 d.d (1H, 7-H,
3
4J = 1.8, J = 8.2 Hz), 6.81–6.84 m (2H, 5-H, 8-H),
7.14 d (2H, 2′-H, 6′-H, J = 8.0 Hz), 7.23 m (1H, 4′-H),
7.25 t (2H, 3′-H, 5′-H, J = 8.0 Hz). Found, %: C 75.30,
75.41; H 6.52, 6.62. C17H18O3. Calculated, %: C 75.53;
H 6.71.
3
4J = 1.8, J = 8.3 Hz), 6.85–6.87 m (2H, 5-H, 8-H).
6-(1-Ethoxy-2-phenylethyl)-2,3-dihydro-1,4-
1
Found, %: C 70.68, 70.77; H 7.16, 7.23. C13H16O3.
Calculated, %: C 70.89; H 7.32.
benzodioxine (4s). Viscous oily material. H NMR
spectrum (CDCl3), δ, ppm: 1.18 t (3H, OCH2CH3, J =
7.2 Hz), 2.89 d.d (1H, J = 6.2, 13.7 Hz) and 3.17 d.d
(1H, J = 7.7, 13.7 Hz) (CH2Ph), 3.28 m and 3.44 m
(1H each, OCH2CH3), 4.27 s (4H, OCH2CH2O),
4.37 d.d (1H, CHOCH2CH3, J = 6.2, 7.7 Hz), 6.74 d.d
(1H, 7-H, 4J = 1.8, 3J = 8.2 Hz), 6.84–6.87 m (2H, 5-H,
8-H), 7.18 d (2H, 2′-H, 6′-H, J = 7.8 Hz), 7.21 m (1H,
4′-H), 7.28 t (2H, 3′-H, 5′-H, J = 7.8 Hz) Found, %:
C 75.79, 75.86; H 6.91, 6.96. C18H20O3. Calculated, %:
C 76.03; H 7.09.
6-[Cyclopropyl(ethoxy)methyl]-2,3-dihydro-1,4-
1
benzodioxine (4n). Viscous oily material. H NMR
spectrum (CDCl3), δ, ppm: 0.25 m (1H), 0.43 m (2H),
0.62 m (1H), and 1.15 m (1H) (cyclopropane); 1.19 t
(3H, OCH2CH3), 3.37 m (2H, OCH2CH3), 3.53 d (1H,
CHOCH2H3, J = 7.6 Hz), 4.26 s (4H, OCH2CH2O),
6.79–6.87 m (3H, Harom). Found, %: C 71.48, 71.62;
H 7.53, 7.58. C14H18O3. Calculated, %: C 71.77;
H 7.74.
6-Bromo-7-[cyclopropyl(methoxy)methyl]-2,3-
dihydro-1,4-benzodioxine (4o). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 0.42 m (3H),
0.55 m (1H), and 1.12 m (1H) (cyclopropane); 3.22 s
(3H, OCH3), 4.11 d (1H, CHOCH3, J = 6.3 Hz), 4.25 s
(4H, OCH2CH2O), 6.97 s and 7.03 s (1H each, 5-H,
8-H). Found, %: C 51.91, 52.04; H 4.87, 4.94.
C13H15BrO3. Calculated, %: C 52.19; H 5.05.
6-(1-Isopropoxy-2-phenylethyl)-2,3-dihydro-1,4-
benzodioxine (4t). Viscous oily material. H NMR
1
spectrum (CDCl3), δ, ppm: 0.99 d and 1.09 d [3H each,
CH(CH3)2, J = 6.2 Hz], 2.85 d.d (1H, J = 5.8, 13.3 Hz)
and 3.05 d.d (1H, J = 8.0, 13.3 Hz) (CH2Ph), 3.46 sept
[1H, CH(CH3)2], 4.27 s (4H, OCH2CH2O), 4.43 d.d
[1H, CHOCH(CH3)2, J = 5.8, 8.0 Hz], 6.75 d.d (1H,
4
3
3
7-H, J = 1.8, J = 8.2 Hz), 6.82 d (1H, 8-H, J =
4
8.2 Hz), 6.86 d (1H, 5-H, J = 1.8 Hz), 7.17 d (2H,
6-Bromo-7-[cyclopropyl(ethoxy)methyl]-2,3-
dihydro-1,4-benzodioxine (4p). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 0.37–0.47 m
(3H), 0.54 m (1H), and 1.11 m (1H) (cyclopropane);
1.17 t (3H, OCH2CH3, J = 7.3 Hz), 3.34 q (2H,
OCH2CH3), 4.20 d (1H, CHOCH2CH3, J = 6.8 Hz),
2′-H, 6′-H, 3J = 7.8 Hz), 7.20 m (1H, 4′-H), 7.26 t (2H,
3
3′-H, 5′-H, J = 7.8 Hz). Found, %: C 76.21, 76.34;
H 7.22, 7.31. C19H22O3. Calculated, %: C 76.48; H 7.43.
7-(1-Methoxyethyl)-3,4-dihydro-2H-1,5-benzodi-
oxepine (6a). Viscous oily material. 1H NMR spectrum
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

MOCHALOV et al.
1228
(CDCl3), δ, ppm: 1.41 d (3H, CHCH3, J = 7.5 Hz),
2.21 m (2H, OCH2CH2CH2O), 3.23 s (3H, OCH3),
4.22 m (5H, OCH2CH2CH2O, CHOCH3), 6.88 d.d
1,1′-(Ethoxymethanediyl)dibenzene (8b). Viscous
oily material. H NMR spectrum (CDCl3), δ, ppm:
1.37 t (3H, OCH2CH3), 3.62 q (2H, OCH2CH3), 5.46 s
(1H, CHOCH2CH3), 7.34 m (2H, Harom), 7.39–7.47 m
(8H, Harom). Found, %: C 84.65, 84.73; H 7.39, 7.48.
C15H16O. Calculated, %: C 84.87; H 7.60.
1
4
3
(1H, 8-H, J = 2.1, J = 8.1 Hz), 6.94 d (1H, 6-H, 4J =
3
2.1 Hz), 6.96 d (1H, 9-H, J = 8.1 Hz). Found, %:
C 68.96, 69.09; H 7.57, 7.63. C12H16O3. Calculated, %:
C 69.21; H 7.75.
6-[Methoxy(phenyl)methyl]-2,3-dihydro-1,4-
1
7-(1-Methoxy-2-phenylethyl)-3,4-dihydro-2H-
1,5-benzodioxepine (6b). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 2.21 quint (2H,
OCH2CH2CH2O, J = 5.6 Hz), 2.87 d.d (1H, J = 7.2,
14.4 Hz) and 3.10 d.d (1H, J = 8.1, 14.4 Hz) (CH2Ph),
3.20 s (3H, OCH3), 4.22 m (4H, OCH2CH2CH2O),
4.26 d.d (1H, CHOCH3, J = 7.2, 8.1 Hz), 6.81 d.d (1H,
benzodioxine (8c). Viscous oily material. H NMR
spectrum (CDCl3), δ, ppm: 3.38 s (3H, OCH3), 4.24 s
(4H, OCH2CH2O), 5.18 s (1H, CHOCH3), 6.84 m (2H,
5-H, 7-H), 6.87 m (1H, 8-H), 7.28 m (1H) and 7.33–
7.38 m (4H) (Ph). Found, %: C 74.74, 74.82; H 6.11,
6.15. C16H16O3. Calculated, %: C 74.98; H 6.29.
4
3
4
6-[Ethoxy(phenyl)methyl]-2,3-dihydro-1,4-
8-H, J = 2.2, J = 8.2 Hz), 6.90 d (1H, 6-H, J =
1
3
benzodioxine (8d). Viscous oily material. H NMR
2.2 Hz), 6.94 d (1H, 9-H, J = 8.2 Hz), 7.14 m (2H,
spectrum (CD2Cl2), δ, ppm: 1.28 t (3H, OCH2CH3, J =
7.6 Hz), 3.52 m (2H, OCH2CH3), 4.24 s (4H,
OCH2CH2O), 5.28 s (1H, CHOCH2CH3 ), 6.84 m (2H,
5-H, 7-H), 6.89 m (1H, 8-H), 7.28 m (1H) and 7.33–
7.39 m (4H) (Ph). Found, %: C 75.21, 75.42; H 6.55,
6.59. C17H18O3. Calculated, %: C 75.53; H 6.71.
2′-H, 6′-H), 7.21 m (1H, 4′-H), 7.25 m (2H, 3′-H,
5′-H). Found, %: C 75.71, 75.84; H 6.89, 6.97.
C18H20O3. Calculated, %: C 76.03; H 7.09.
7-(1-Ethoxy-2-phenylethyl)-3,4-dihydro-2H-1,5-
1
benzodioxepine (6c). Viscous oily material. H NMR
spectrum (CDCl3), δ, ppm: 1.15 t (3H, OCH2CH3, J =
7.1 Hz), 2.21 quint (2H, OCH2CH2CH2O, J = 5.4 Hz),
2.86 d.d (1H, J = 5.7, 13.4 Hz) and 3.11 d.d (1H, J =
7.8, 13.4 Hz) (CH2Ph), 3.28 m and 3.41 m (1H each,
OCH2CH3), 4.22 m (4H, OCH2CH2CH2O), 4.35 d.d
(1H, CHOCH2CH3, J = 5.7, 7.8 Hz), 6.81 d.d (1H,
6-[Isopropoxy(phenyl)methyl]-2,3-dihydro-1,4-
1
benzodioxine (8e). mp 62–63°C. H NMR spectrum
(CD2Cl2), δ, ppm: 1.21 d and 1.23 d [3H each,
CH(CH3)2, J = 5.6 Hz], 3.67 sept [1H, OCH(CH3)2],
4.24 s (4H, OCH2CH2O), 5.41 s [1H, CHOCH(CH3)2],
6.82 m (2H, 5-H, 7-H), 6.88 m (1H, 8-H), 7.27 m
(1H) and 7.32–7.39 m (4H) (Ph). Found, %: C 75.81,
75.93; H 6.86, 6.94. C18H20O3. Calculated, %: C 76.03;
H 7.09.
4
3
4
8-H, J = 1.8, J = 8.0 Hz), 6.90 d (1H, 6-H, J =
3
1.8 Hz), 6.93 d (1H, 9-H, J = 8.0 Hz), 7.14 d (2H,
2′-H, 6′-H, J = 7.7 Hz), 7.21 m (1H, 4′-H), 7.25 m (2H,
3′-H, 5′-H). Found, %: C 76.22, 76.37; H 7.23, 7.31.
C19H22O3. Calculated, %: C 76.48; H 7.43.
6-[Methoxy(4-methylphenyl)methyl]-2,3-dihy-
dro-1,4-benzodioxine (8f). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 2.36 s (3H, CH3),
3.39 s (3H, OCH3), 4.24 s (4H, OCH2CH2O), 5.15 s
(1H, CHOCH3), 6.84 m (2H, 7-H, 8-H), 6.90 m (1H,
5-H), 7.17 d (2H, 3′-H, 5′-H, J = 7.8 Hz), 7.26 d (2H,
2′-H, 6′-H, J = 7.8 Hz). Found, %: C 75.33, 75.45;
H 6.48, 6.55. C17H18O3. Calculated, %: C 75.53; H 6.71.
7-(1-Isopropoxy-2-phenylethyl)-3,4-dihydro-2H-
1,5-benzodioxepine (6d). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 0.99 d and 1.09 d
[3H each, CH(CH3)2, J = 5.6 Hz], 2.21 quint (2H,
OCH2CH2CH2O, J = 5.3 Hz), 2.85 d.d (1H, J = 5.3,
13.3 Hz) and 3.04 d.d (1H, J = 8.0, 13.3 Hz) (CH2Ph),
3 . 4 5 s e p t [ 1 H , C H ( C H 3 ) 2 ] , 4 . 2 3 t ( 4 H,
OCH2CH2CH2O, J = 5.3 Hz), 4.44 d.d [1H,
CHOCH(CH3)2, J = 5.7, 7.8 Hz], 6.85 d.d (1H, 8-H,
6-[Ethoxy(4-methylphenyl)methyl]-2,3-dihydro-
1,4-benzodioxine (8g). Viscous oily material. 1H NMR
spectrum (CDCl3), δ, ppm: 1.31 t (3H, OCH2CH3, J =
7.4 Hz) 2.37 s (3H, CH3), 3.52 m (2H, OCH2CH3),
4.23 s (4H, OCH2CH2O), 5.25 s (1H, CHOEt), 6.81 m
(2H, 7-H, 8-H), 6.87 m (1H, 5-H), 7.14 d (2H, 3′-H,
5′-H, J = 7.8 Hz), 7.24 d (2H, 2′-H, 6′-H, J = 7.8 Hz).
Found, %: C 75.87, 75.92; H 6.88, 7.01. C18H20O3.
Calculated, %: C 76.03; H 7.09.
3
4J = 1.8, J = 8.2 Hz), 6.92–6.95 m (2H, 6-H, 9-H),
7.15 d (2H, 2′-H, 6′-H, J = 8.0 Hz), 7.21 m (1H, 4′-H),
7.26 m (2H, 3′-H, 5′-H). Found, %: C 76.71, 76.78;
H 7.53, 7.61. C20H24O3. Calculated, %: C 76.89; H 7.74.
1,1′-(Methoxymethanediyl)dibenzene (8a).
1
Viscous oily material. H NMR spectrum (CDCl3), δ,
ppm: 3.46 s (3H, OCH3), 5.32 s (1H, CHOCH3),
7.32 m (2H, Harom), 7.39–7.46 m (8H, Harom). Found,
%: C 84.62, 84.68; H 6.87, 6.98. C14H14O. Calculated,
%: C 84.81; H 7.12.
6-[Isopropoxy(4-methylphenyl)methyl]-2,3-dihy-
1
dro-1,4-benzodioxine (8h). mp 69–70°C. H NMR
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HYDROCHLORIC ACID AS AN EFFICIENT CATALYST
1229
spectrum (CDCl3), δ, ppm: 1.23 d and 1.24 d [3H each,
CH(CH3)2, J = 5.6 Hz], 2.35 s (3H, CH3), 3.68 sept
[1H, CH(CH3)2], 4.24 s (4H, OCH2CH2O), 5.39 s [1H,
CHOCH(CH3)2], 6.82 m (2H, 7-H, 8-H), 6.91 m
(1H, 5-H), 7.15 d (2H, 3′-H, 5′-H, J = 7.8 Hz), 7.26 d
(2H, 2′-H, 6′-H, J = 7.8 Hz). Found, %: C 76.22,
76.37; H 7.28, 7.38. C19H22O3. Calculated, %: C 76.48;
H 7.43.
1H NMR spectrum (CDCl3) δ, ppm: 1.14 t (3H,
OCH2CH3, J = 6.2 Hz), 3.38 m (2H, OCH2CH3),
4.21 s (4H, OCH2CH2O), 5.33 s (1H, CHOCH2CH3,
6.75–6.81 m (3H, 5-H, 7-H, 8-H), 7.34 s (4H, Harom).
Found, %: C 66.67, 66.82; H 5.36, 5.48. C17H17ClO3.
Calculated, %: C 67.00; H 5.62.
3-[(2,3-Dihydro-1,4-benzodioxin-6-yl)(ethoxy)-
methyl]benzonitrile (8n). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 1.27 t (3H,
OCH2CH3, J = 7.1 Hz), 3.48 m and 3.54 m (1H each,
OCH2CH3), 4.25 s (4H, OCH2CH2O), 5.26 s (1H,
6-[Methoxy(4-methoxyphenyl)methyl]-2,3-dihy-
dro-1,4-benzodioxine (8i). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 3.33 s (3H,
CHOCH3), 3.78 s (3H, C6H4OCH3), 4.23 s (4H,
OCH2CH2O), 5.10 s (1H, CHOCH3), 6.79 m (3H, 5-H,
7-H, 8-H), 6.85 d (2H, 3′-H, 5′-H, J = 8.4 Hz), 7.24 d
(2H, 2′-H, 6′-H, J = 8.4 Hz). Found, %: C 71.06,
71.18; H 6.17, 6.22. C17H18O4. Calculated, %: C 71.31;
H 6.34.
4
3
CHOCH2CH3), 6.78 d.d (1H, 7-H, J = 1.8, J =
3
8.3 Hz), 6.84 m (2H, 5-H, 8-H), 7.41 t (1H, 5-H, J =
8.0 Hz), 7.52 d (1H, 6′-H, J = 8.0 Hz), 7.58 d (1H,
4′-H, J = 8.0 Hz), 7.67 s (1H, 2′-H). Found, %:
3
3
C 72.85, 73.02; H 5.61, 5.68; N 4.51, 4.63. C18H17NO3.
Calculated, %: C 73.20; H 5.80; N 4.74.
6-[Ethoxy(4-methoxyphenyl)methyl]-2,3-dihy-
dro-1,4-benzodioxine (8j). Viscous oily material.
1H NMR spectrum (CDCl3), δ, ppm: 1.26 t (3H,
OCH2CH3, J = 7.1 Hz), 3.50 m (2H, OCH2CH3),
3.80 s (3H, OCH3), 4.23 s (4H, OCH2CH2O), 5.23 s
(1H, CHOCH2CH3), 6.82 m (2H, 7-H, 8-H), 6.87 m
(1H, 5-H), 6.88 d (2H, 3′-H, 5′-H, J = 8.4 Hz), 7.26 d
(2H, 2′-H, 6′-H, J = 8.4 Hz). Found, %: C 71.67,
71.82; H 6.51, 6.63. C18H20O4. Calculated, %: C 71.98;
H 6.71.
6-[Ethoxy(thiophen-2-yl)methyl]-2,3-dihydro-
1,4-benzodioxine (8o). bp 254–255°C (29 mm).
1H NMR spectrum (CDCl3), δ, ppm: 1.31 t (3H,
OCH2CH3, J = 6.8 Hz), 3.59 m (2H, OCH2CH3),
4.24 s (4H, OCH2CH2O), 5.53 s (1H, CHOCH2CH3),
6.89–6.93 m (4H, 3′-H, 4′-H, 7-H, 8-H.), 7.02 d (1H,
5-H, J = 1.8 Hz), 7.26 d (1H, 5′-H, J = 4.9 Hz).
Found, %: C 64.88, 64.97; H 5.63, 5.72. C15H16O3S.
Calculated, %: C 65.19; H 5.84.
4
4-[(4-Fluorophenyl)(methoxy)methyl]-1,2-di-
methoxybenzene (8p). Viscous oily material. 1H NMR
spectrum (CDCl3), δ, ppm: 3.38 s (3H, CHOCH3),
3.87 s (3H, OCH3), 3.88 s (3H, OCH3), 5.9 s (1H,
CHOCH3), 6.84–6.88 m (3H, 3-H, 5-H, 6-H), 7.03 t
6-[Isopropoxy(4-methoxyphenyl)methyl]-2,3-di-
1
hydro-1,4-benzodioxine (8k). mp 80–81°C. H NMR
spectrum (CD2Cl2), δ, ppm: 1.20 d and 1.21 d [3H
each, CH(CH3)2, J = 5.8 Hz], 3.65 sept [1H,
OCH(CH3)2], 3.80 s (3H, OCH3), 4.25 s (4H,
OCH2CH2O), 5.33 s [1H, CHOCH(CH3)2], 6.81 s (2H,
7-H, 8-H), 6.86 s (1H, 5-H), 6.87 d (2H, 3′-H, 5′-H, J =
8.4 Hz), 7.27 d (2H, 2′-H, 6′-H, J = 8.4 Hz). Found, %:
C 72.28, 72.44; H 6.88, 6.91. C19H22O4. Calculated, %:
C 72.59; H 7.05.
3
(2H, 3′-H, 5′-H, JHF = 8.2, JHH = 8.2 Hz), 7.31 d.d
3
(2H, 2′-H, 6′-H, JHF = 5.4, JHH = 8.2 Hz). Found, %:
C 69.22, 69.33; H 5.98, 6.07. C16H17FO3. Calculated,
%: C 69.55; H 6.20.
4-[(4-Fluorophenyl)(isopropoxy)methyl]-1,2-di-
methoxybenzene (8q). Viscous oily material. 1H NMR
spectrum (CDCl3), δ, ppm: 1.23 d and 1.25 d [3H each,
CH(CH3)2, J = 5.8 Hz], 3.67 sept [1H, OCH(CH3)2],
3.87 s (3H, OCH3), 3.88 s (3H, OCH3), 5.44 s [1H,
CHOCH(CH3)2], 6.84 d (1H, 5-H, J = 7.8 Hz),
6-[(4-Fluorophenyl)(isopropoxy)methyl]-2,3-di-
1
hydro-1,4-benzodioxine (8l). mp 83–84°C. H NMR
spectrum (CD2Cl2), δ, ppm: 1.20 d and 1.22 d
[3H each, CH(CH3)2, J = 5.8 Hz], 3.65 sept [1H,
OCH(CH3)2], 4.25 s (4H, OCH2CH2O), 5.37 s [1H,
4
3
6.87 d.d (1H, 6-H, J = 1.8, J = 7.8 Hz), 6.89 d (1H,
4
3
4
CHOCH(CH3)2], 6.78 d.d (1H, 7-H, J = 1.8, J =
3-H, J = 1.8 Hz), 7.01 t (2H, 3′-H, 5′-H, JHF = 8.4,
3
8.1 Hz), 6.82 d (1H, 8-H, J = 8.1 Hz), 6.86 d (1H,
3JHH = 8.4 Hz), 7.32 d.d (2H, 2′-H, 6′-H, JHF = 5.4,
3JHH = 8.4 Hz). Found, %: C 70.77, 70.84; H 6.78,
6.85. C18H21FO3. Calculated, %: C 71.03; H 6.96.
4
5-H, J = 1.8 Hz), 7.00 t (2H, 3′-H, 5′-H, JHF = 8.2,
3JHH = 8.2 Hz), 7.31 d.d (2H, 2′-H, 6′-H, JHF = 5.4,
3JHH = 8.2 Hz). Found, %: C 71.24, 71.41; H 6.08,
6.18. C18H19FO3. Calculated, %: C 71.51; H 6.33.
6-Bromo-7-[methoxy(phenyl)methyl]-2,3-dihy-
1
dro-1,4-benzodioxine (8r). mp 74–75°C. H NMR
6-[(4-Chlorophenyl)(ethoxy)methyl]-2,3-dihy-
dro-1,4-benzodioxine (8m). bp 267–268°C (20 mm).
spectrum (CD2Cl2), δ, ppm: 3.39 s (3H, OCH3), 4.25 s
(4H, OCH2CH2O), 5.58 s (1H, CHOCH3), 7.02 s and
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

MOCHALOV et al.
1230
7.10 s (1H each, 5-H, 8-H); 7.31 m (1H), 7.36 m (2H),
and 7.42 m (2H) (Ph). Found, %: C 57.02, 57.18;
H 4.31, 4.39. C16H15BrO3. Calculated, %: C 57.33;
H 4.51.
7.48 d.d (1H, 5′-H, J3′,5′ = 0.9, J4′,5′ = 4.9 Hz), 7.99 s
(1H, 8-H), 9.33 br.s (1H, NH). Found, %: C 61.21,
61.32; H 4.45, 4.53; N 2.99, 3.07. C22H20ClNO4S.
Calculated, %: C 61.46; H 4.69; N 3.26.
6-Bromo-7-[ethoxy(phenyl)methyl]-2,3-dihy-
dro-1,4-benzodioxine (8s). Viscous oily material.
1H NMR spectrum (CD2Cl2), δ, ppm: 1.28 t (3H,
OCH2CH3, J = 6.6 Hz), 3.55 m (2H, OCH2CH3),
4.25 s (4H, OCH2CH2O), 5.69 s (1H, CHOCH2CH3),
7.04 s and 7.06 s (1H each, 5-H, 8-H); 7.29 m (1H),
7.35 m (2H), and 7.42 m (2H) (Ph). Found, %:
C 58.16, 58.23; H 4.72, 4.79. C17H17BrO3. Calculated,
%: C 58.47; H 4.91.
N-{7-[Ethoxy(3-fluorophenyl)methyl]-2,3-dihy-
dro-1,4-benzodioxin-6-yl}cyclopropanecarbox-
1
amide (8x). mp 137–138°C. H NMR spectrum
(CDCl3), δ, ppm: 0.70–0.85 m (3H), 0.94 m (1H), and
1.27 m (1H) (C3H5); 1.34 t (3H, OCH2CH3, J =
6.9 Hz), 3.63 m (2H, OCH2CH3), 4.25 m (4H,
OCH2CH2O), 5.34 s (1H, CHOCH2CH3), 6.67 s (1H,
5-H), 6.95 d.d.d (1H, 4′-H, JHF = 8.0, 4JHH = 2.4, 3JHH
=
8.0 Hz), 7.02 d (1H, 2-H, JHF = 6.0 Hz), 7.11 d (1H,
6′-H, 3J = 8.2 Hz), 7.26 d.d (1H, 5′-H, JHF = 8.0, 3JHH
=
6-[Methoxy(phenyl)methyl]-7-nitro-2,3-dihydro-
1,4-benzodioxine (8t) was not isolated in the pure
state because of its low concentration in the mixture
with unreacted diarylmethanol.
8.2 Hz), 7.70 s (1H, 8-H), 8.57 br.s (1H, NH). Found,
%: C 67.63, 67.73; H 5.76, 5.85; N 3.51, 3.67.
C21H22NFO4. Calculated, %: C 67.91; H 5.97; N 3.77.
N-{7-[Ethoxy(4-methylphenyl)methyl]-2,3-di-
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1
amide (8u). mp 114–115°C. H NMR spectrum
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(CDCl3), δ, ppm: 0.72 m (2H), 0.90 m (1H), 0.95 m
(1H), and 1.31 m (1H) (C3H5); 1.32 t (3H, OCH2CH3,
J = 7.2 Hz), 2.34 s (3H, CH3), 3.61 q (2H, OCH2CH3,
J = 7.2 Hz), 4.23 m (4H, OCH2CH2O), 5.35 s (1H,
CHOCH2CH3), 6.61 s (1H, 5-H), 7.12 d (2H, 3′-H,
5′-H, J = 7.8 Hz), 7.19 d (2H, 2′-H, 6′-H, J = 7.8 Hz),
7.74 s (1H, 8-H), 8.73 br.s (1H, NH). Found, %:
C 71.68, 71.77; H 6.62, 6.74; N 3.58, 3.63. C22H25NO4.
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1
(8v). Viscous oily material. H NMR spectrum
(CDCl3) δ, ppm: 1.09 t (3H, OCH2CH3, J = 6.8 Hz),
2.35 s (3H, CH3), 3.33 m and 3.41 m (1H each,
OCH2CH3), 3.46 d and 3.54 d (1H each, CH2Ph, J =
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5′-H, J = 8.0 Hz), 7.09 d (2H, 2′-H, 6′-H, J = 8.0 Hz),
7.12 m (2H) and 7.29 m (3H) (Ph), 7.76 s (1H, 8-H),
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6.36; N 3.12, 3.23. C26H27NO4. Calculated, %:
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N-{7-[(4-Chlorophenyl)(ethoxy)methyl]-2,3-di-
hydro-1,4-benzodioxin-6-yl}thiophene-2-carbox-
amide (8w). Viscous oily material. 1H NMR spectrum
(CDCl3), δ, ppm: 1.35 t (3H, OCH2CH3, J = 7.2 Hz),
3.67 m (2H, OCH2CH3), 4.28 m (4H, OCH2CH2O),
5.38 s (1H, CHOCH2CH3), 6.71 s (1H, 5-H), 7.07 d.d
(1H, 4′-H, J3′,4′ = 3.7, J4′,5′ = 4.9 Hz), 7.25 s (4H,
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

HYDROCHLORIC ACID AS AN EFFICIENT CATALYST
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