ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 6, pp. 909–910. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © N.F. Kirillov, E.A. Nikiforova, 2014, published in Zhurnal Organicheskoi Khimii, 2014, Vol. 50, No. 6, pp. 923–924.
SHORT
COMMUNICATIONS
Consecutive Reactions of Methyl 1-Bromocyclohexane-
carboxylate with Zinc and Nitrobenzaldehydes
N. F. Kirillov and E. A. Nikiforova
Perm State National Research University, ul. Bukireva 15, Perm, 614990 Russia
e-mail: kirillov@psu.ru
Received December 27, 2013
DOI: 10.1134/S1070428014060281
Carbonyl compounds are known to react with
Reformatsky reagents to give β-hydroxy esters [1, 2].
We examined reactions of Reformatsky reagent II
derived from methyl 1-bromocyclohexanecarboxylate
(I) with nitro-substituted benzaldehydes IVa–IVc.
Taking into account that compounds containing a nitro
group hamper formation of organozinc derivatives [3],
the reaction was carried out in two steps. In the first
step, methyl 1-bromocyclohexanecarboxylate (I) was
treated with zinc to obtain the corresponding bromo-
zinc derivative II, and the latter was then brought into
reaction with nitrobenzaldehyde IVa–IVc. However,
instead of expected β-hydroxy esters, we isolated sub-
stituted dispirotetrahydropyran-2,4-diones, 16-(nitro-
phenyl)-15-oxadispiro[5.1.5.3]hexadecane-7,14-diones
VIa–VIc.
Compounds VIa–VIc (general procedure). A mix-
ture of 3.0 g of zinc, 5.30 g (24 mmol) of ester I, and
a catalytic amount (5 mg) of HgCl2 in 40 mL of ben-
zene was heated for 1.5 h under reflux. Nitrobenzalde-
hyde IVa–IVc, 3.02 g (20 mmol), was added to the
Reformatsky reagent thus obtained, and the mixture
was heated under reflux for 2 h more. The mixture was
then hydrolyzed with 5% acetic acid, the organic layer
was separated and dried over Na2SO4, the solvent was
distilled off, and the residue was recrystallized from
ethyl acetate.
16-(2-Nitrophenyl)-15-oxadispiro[5.1.5.3]hexa-
decane-7,14-dione (VIa). Yield 1.56 g (35%),
mp 198–199°C. IR spectrum, ν, cm–1: 1749, 1713
(C=O). 1H NMR spectrum, δ, ppm: 0.50–2.20 m (20H,
CH2), 6.50 s (1H, 16-H), 7.56 t (1H, Harom, J = 7.8 Hz),
7.73 t (1H, Harom, J = 7.8 Hz), 7.88 d (1H, Harom, J =
7.8 Hz), 7.97 d (1H, Harom, J = 7.8 Hz). Found, %:
C 68.02; H 6.69; N 3.71. C21H25NO5. Calculated, %:
C 67.91; H 6.78; N 3.77.
Presumably, in the absence of carbonyl compound
Reformatsky reagent II reacts with the second ester I
molecule to produce intermediate III. Analogous self-
condensation of Reformatsky reagent in the absence of
carbonyl compounds was reported in [4]. The reaction
of III with nitrobenzaldehydes IVa–IVc afforded com-
pounds VIa–VIc through intermediates Va–Vc.
16-(3-Nitrophenyl)-15-oxadispiro[5.1.5.3]hexa-
decane-7,14-dione (VIb). Yield 1.87 g (42%),
mp 188–189°C. IR spectrum, ν, cm–1: 1753, 1711
ZnBr COOMe
Zn
II
Br
ZnBr
–MeOZnBr
COOMe
COOMe
O
I
II
III
OZnBr
COOMe
O
Ar
ArCHO (IVa–IVc)
–MeOZnBr
Ar
O
O
O
Va–Vc
VIa–VIc
Ar = 2-O2NC6H4 (a), 3-O2NC6H4 (b), 4-O2NC6H4 (c).
909
Kirillov
