Reactions of cyclic boric acids esters with paraformaldehyde

Article abstract of DOI:10.1134/S1070363211030169

Reactions of five- and six-membered cyclic esters of boric acids with paraformaldehyde lead to the corresponding 1,3-dioxacycloalkanes. It is shown that trans-isomers of 2,4,5-substituted 1,3,2-dioxaborinanes react faster than their cis-isomers.

Full text of DOI:10.1134/S1070363211030169

ISSN 1070-3632, Russian Journal of General Chemistry, 2011, Vol. 81, No. 3, pp. 542–544. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © Yu.E. Brusilovskii, V.V. Kuznetsov, 2011, published in Zhurnal Obshchei Khimii, 2011, Vol. 81, No. 3, pp. 446–448.
Reactions of Cyclic Boric Acids Esters with Paraformaldehyde
Yu. E. Brusilovskiia and V. V. Kuznetsovb,c
a Bogatskii Physicochemical Institute of National Academy of Sciences of Ukrane, Odessa, Ukraine
b Institute of Physics of Molecules and Crystals of the Ufa Scientific Center of Russian Academy of Sciences,
pr. Octyabrya 71, Ufa, 450054 Russia
e-mail: kuz@anrb.ru
c Ufa State Oil Technical University, Ufa, Russia
Received March 18, 2010
Abstract—Reactions of five- and six-membered cyclic esters of boric acids with paraformaldehyde lead to the
corresponding 1,3-dioxacycloalkanes. It is shown that trans-isomers of 2,4,5-substituted 1,3,2-dioxaborinanes
react faster than their cis-isomers.
DOI: 10.1134/S1070363211030169
R1
R2
R1
R2
One of the promising directions in chemistry of
cycloalkane heteroanalogs is connected with the
revealing the possibility of mutual transformations of
compounds of different classes. In particular, the
reaction of acyclic organoboron compound with 1,3-
dioxa- as well as with 1,3-dioxa-2-heterocycloalkanes
containing silicon, sulfur, germanium, and arsenic
atoms in the position 2 of the ring leads to
corresponding 1,3-dioxa-2-boronocycloalkanes. The
reverse process is also possible. The reaction of
carbonyl compounds with 1,3-dioxa-2-boronocyclo-
alkanes leads to the deborination of heterocyclic sys-
tem and the formation of the corresponding 1,3-
dioxacycloalkanes. We have shown recently that the
reaction of substituted 1,3,2-dioxaborinanes with
paraformaldehyde, as well as with acetic, propionic,
and isobutyric aldehydes yields the corresponding
dioxanes [2–5]. Here we report on further studies of
the reaction of five- and six-membered cyclic esters of
boric acids Ia–XIIa with paraformaldehyde.
O
O
O
O
(CH2O)n, ZnCl2
CH2
B OR
−(ROBO)3
Ib−VIIb
Iа−VIIа
O
O
B
O
(CH2O)n, ZnCl2
−(i-C4H9OBO)3
Oi-C4H9
CH2
O
H3C
H3C
VIIIа
VIIIb
Data of Table 2 show that the conversion of cyclic
boric esters to the corresponding 1,3-dioxanes is not high.
According to GLC data it does not exceed 30%. After
8 h since the start of the reaction the products, formals
Xb and XIb, have higher content of trans-form as
compared to the expected results. Inasmuch as the
formation of cyclic boric esters and 1,3-dioxanes from
stereoisomeric 1,3-diols proceeds stereospecifically
[6–8], these data show the difference in the rate of the
reactions of cis- and trans-isomers of compounds Xa
and XIa with paraformaldehyde. The ratio of isomers
in the samples of 1,3-dioxanes obtained by an in-
dependent synthesis from the corresponding 1,3-diols
and paraformaldehyde was taken as standard [8, 9]. In
the case of ester Xa and 1,3-dioxane Xb the samples
with different ratio of cis- and trans-forms were
studied [9, 10].
It is established that the reaction under investigation
leads to the corresponding 1,3-dioxolanes and 1,3-
dioxanes Ib–XIIb. It takes place while heating a
mixture of starting substances in the presence of a
catalytic amount of zinc chloride. Yields of low-
boiling products Ib–VIIIb vary from 24 to 82% (see
Table 1). No unambiguous dependence of the yield on
the degree of substitution of the ring, on the size of the
cycle, and on the number of carbon atoms in the
alkoxy substituent at the boron atom was found.
Note that 1,3,2-dioxaborinanes Xa, XIa are
configurationally stable. They do not isomerize under
542

543
REACTIONS OF CYCLIC BORIC ACIDS ESTERS WITH PARAFORMALDEHYDE
Table 1. Yield of 1,3-dioxacycloalcanes Ib–VIIIb in the reac-
tions of cyclic boric esters Ia–VIIIa with paraformaldehyde
Table 2. Conversion of 1,3,2-dioxaborinanes IXa–XIIa and
stereoisomeric composition of 1,3,2-dioxaborinanes (a) and
1,3-dioxanes (b)
Boric esters
R
R1
R2
Yield, %
cis:trans
С4Н9
i-C5H11
C6H13
C7H15
i-C4H9
C7H15
i-C4H9
–
Н
Н
77
24
27
31
82
53
30
36
Ia
Boric Conversion
after 8 h
а
b
(counter
synthesis)
–
H
H
IIa
esters
degree, %
(before
reaction)
–
H
H
IIIa
IVa
Va
а
b
H
H
30
25
–
–
IXa
Xa
CH3
CH3
CH3
–
H
77:23
35:65
66:34
83:17
67:33
39:61
66:34
80:20
88:12 62:38
48:52 33:67
68:32 57:43
H
VIa
VIIa
VIIIa
20
1
XIa
CH3
–
XIIa
26:74
–
O
O
the action of zinc chloride [5, 6]. Hence, considering
the accuracy of GLC measurements (±3%) [11], the
rate of the reaction of trans-form of cyclic boric esters
Xa, XIa with paraformaldehyde is higher than that of
the cis-form leading to the increase in the content of
trans-isomers of 1,3-dioxanes Xb, XIb at the end of
the controlled period. It agrees with the known data
that the rate of borination, the reversed reaction, in the
case of cis-isomer of dioxane Xb is higher than that of
the corresponding trans-form [9].
H3C
i-C4H9
B
+
−
C6H5
ZnCl2
O
O
O
O
ZnCl2
ZnCl2
H3C
i-C4H9
B
H3C
(CH2O)n
C6H5
C6H5
XIIb
XIIа
O
O
(CH2O)n, ZnCl2
C6H5
C6H5
B i-C3H7
Note that the reverse reaction, borination of 1,3-
dioxanes with the acyclic boric esters under the
analogous conditions leads to the preferred formation
of the target 1,3,2-dioxaborinanes [9, 13]. Hence, it is
thermodynamically more favorable.
−(i-C3H7BO)3
O
IXb
O
IXа
O
O
(CH2O)n, ZnCl2
R
i-C4H9
R
H3C
B
−(i-C4H9BO)3
O
O
EXPERIMENTAL
H3C
Xb−XIb
Xа−XIа
GLC analysis was carried out on a Tsvet-126
chromatograph equipped with the flame ionization
detector and the 3000×4 mm column filled with 5% of
OV-17 on the Chromaton N-Super carrier, carrier gas
argon. Quantitative ratio of 1,3,2-dioxaborinane and
1,3-dioxane was evaluated by means of the internal
reference method with the calibrating coefficients
established according to the procedure [11].
R = i-C3H7 (X), C6H5CH2 (XI).
O
O
O
B
O
(CH2O)n, ZnCl2
H3C
H3C
C6H5
i-C4H9
−(i-C4H9BO)3
C6H5
XIIа
XIIb
Molecules of the ester XIIa are configurationally
unstable and relatively easily isomerize under the
action of catalytic amounts of ZnCl2 giving the more
stable trans-isomer [6, 12].
Boric esters Ia–XIIa were obtained by the reaction
of acyclic trialkyl borates or the esters of isopropyl- or
isobutylboric acids with the corresponding 1,2 and 1,3-
diols according to the general procedure [14]. The
independent synthesis of 1,3-dioxanes IXb–XIIb is
described in [8, 9, 15]. 1,3-Dioxacycloalkanes Ib-XIIb
were identified by their physicochemical constants [15,
16]. Samples of 2-isopropyl-1,3-butanediol with the
varied ratio of erythro- and treo-forms necessary for
It may be suggested that due to that the approach of
the aldehyde molecule from the side of more reactive
O3 oxygen atom is complicated decreasing the activity
of borinane XIIa in the reaction with parafor-
maldehyde.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 81 No. 3 2011

544
BRUSILOVSKII, KUZNETSOV
8. Bogastskii, A.V., Samitov, Yu.Yu., Gren’, A.I., and
Soboleva, S.G., Khim. Geterotsikl. Soedin., 1971, no. 7,
p. 893.
preparing model compounds, boric ester Xa and 1,3-
dioxane Xb, were obtained according to the procedures
[8, 17, 18].
9. Kuznetsov, V.V., Khim. Geterotsikl. Soedin., 2002, no. 8,
In the case of preparative isolation of 1,3-
dioxacycloalkanes a mixture of 0.1 mol of cyclic boric
ester Ia–VIIIa, 0.5 mol of paraformaldehyde, and 0.7 g
of anhydrous zinc chloride was heated to 130–150°C
and the target low-boiling product was distilled off. In
the analytic procedures a mixture of 0.01 mol of boric
ester IXa–XIIa, 0.05 mol of paraformaldehyde, and
0.5 g of the anhydrous ZnCl2 was heated at 130°C for
8 h with the intermittent sampling for GLC analysis.
p. 1149.
10. Kuznetsov, V.V., Khim. Geterotsikl. Soedin., 2002,
no. 10, p. 1453.
11. Vyakhirev, D.A. and Shushunova, A.F., Rukovodstvo po
gazovoi khromatografii (Handbook of Gas Chromato-
graphy), Moscow: Vysshaya Shkola, 1975, p. 129.
12. Kuznetsov, V.V. and Spirikhin, L.V., Zh. Strukt. Khim.,
2000, vol. 41, no. 4, p. 844.
13. Kuznetsov, V.V., Tereshchenko, A.V., and Gren’, A.I.,
Zh. Obshch. Khim., 1996, vol. 66, no. 2, p. 270.
REFERENCES
14. Gren’, A.I. and Kuznetsov, V.V., Khimiya tsiklicheskikh
efirov bornykh kislot (Chemistry of Cyclic Boric Acid
Esters), Kiev: Naukova Dumka, 1988.
1. Kuznetsov, V.V., Khim. Geterotsikl. Soedin., 2006,
no. 5, p. 643.
15. Rakhmankulov, D.L., Syrkin, A.M., Karakhanov, R.A.,
Kantor, E.A., Zlotskii, S.S., and Imashev, U.B., Fiziko-
khimicheskie svoictva 1,3-dioksanov (Physicochemical
Properties of 1,3-Dioxanes), Moscow: Khimiya, 1980.
2. Kuznetsov, V.V. and Gren’, A.I., Zh. Obshch. Khim.,
1963, vol. 33, no. 6, p. 1432.
3. Kuznetsov, V.V., Khim. Geterotsikl. Soedin., 2001, no. 1,
p. 136.
16. Elderfield, R. and Short, F.V., 1,3-Dioksolany.
4. Kuznetsov, V.V. and Brusilovskii, Yu.E., Abstract of
Papers, XX Ukrane Conf. on Organic Chemistry,
Odessa, 2004, p. 235.
Geterotsiklicheskie
soedineniya
(1,3-Dioxolanes.
Heterocyclic Compounds), Elderfield, R., Ed., Moscow:
Inostrannaya Literatura, 1961, vol. 5, no. 7.
5. Kuznetsov, V.V., Zh. Org. Khim., 2001, vol. 37, no. 9,
17. Bogatskii, A.V., Samitov, Yu.Yu., Gren, A.I., and
p. 1423.
Soboleva, S.G., Tetrahedron, 1975, vol. 31, no. 6, p. 489.
6. Kuznetsov, V.V., Alekseeva, E.A., and Gren’, A.I.,
Khim. Geterotsikl. Soedin., 1995, no. 9, p. 1291.
7. Kuznetsov, V.V., Bochkor, S.A., and Spirikhin, L.V.,
18. Bogatskii, A.V., Luk’yanenko, N.G., Lyamtsev,a L.N.,
Teterina, T.G., and Vasilova, I., Zh. Org. Khim., 1981,
vol. 17, no. 6, p. 1202.
Bashk. Khim. Zh., 2000, vol. 7, no. 5, p. 23.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 81 No. 3 2011