1722
PEVZNER
amine in 3 ml of benzene was added dropwise with
stirring at 15 20 C to a solution of 3 g of acyl
chloride XIX in 15 ml of benzene. The mixture was
stirred for 2 h and left overnight. After that, diethyl-
amine hydrochloride was filtered off, and the benzene
filtrate was washed with dilute hydrochloric acid and
then with water, dried over calcium chloride, and
distilled in a vacuum to give 1.1 g of amide XX, bp
carboxylate XXVI. Sodium, 0.8 g, was dissolved in
15 ml of ethanol, and a solution of 8.2 g of bromide
XVI in 20 ml of benzene was added with stirring. The
reaction mixture was stirred for 16 h at 45 50 C, the
precipitate that formed was filtered off, the solvents
were removed at reduced pressure, and the residue
was treated with 20 ml of water. The resulting mixture
was extracted with ether, the extract was dried over
calcium chloride, the ether was distilled off, and the
residue was distilled in a vacuum to give 4.4 g of
1
125 126 C (1 mm). H NMR spectrum (CDCl3), ,
ppm: 1.29 m [CH3-ethyl + (CH3)3C], 3.29 3.49 br.s
(CH2N), 4.72 s (CH2Cl), 6.12 s (H4-furan).
ester XXVI, bp 104 105 C (1 mm). H NMR spec-
1
trum, , ppm: 1.27 s [(CH3)3C], 3.27 s (CH3O), 3.75 s
3-Methyl-5-tert-butylfuran-2-carboxylic acid
chloride XXI. 3-Methyl-5-tert-butylfuran-2-carbox-
ylic acid, 9 g, was suspended in 50 ml of benzene,
and 10.3 g of finely ground phosphorus pentachloride
was added in small portions with stirring. After the
addition was complete, the reaction mixture was re-
fluxed for 4 h and distilled in a vacuum to give 9.1 g
of acyl chloride XXI, bp 86 C (1 mm).
(CH3OOC), 4.47 s (CH2O-furan), 6.05 s (H4-furan).
3-Methoxymethyl-5-tert-butylfuran-2-carboxylic
acid chloride XXVIII. Compound XXVI, 4.4 g, was
refluxed for 4 h with a solution of 2.2 g of potassium
hydroxide in 20 ml of water. The resulting homo-
geneous solution was acidified, and compound XXVII
was extracted with ether. The combined extracts were
dried over calcium chloride, the ether was distilled
off, and the residue was kept in a vacuum. Acid
XXVII, 3.5 g, was obtained as a viscous liquid. The
product was dissolved in 26 ml of benzene, 0.5 ml of
DMF and 4 ml of thionyl chloride were added, and
the resulting mixture was refluxed with stirring for
4 h. Vacuum distillation of the reaction mixture gave
2.8 g of acyl chloride XXVIII, bp 100 C (1 mm).
3-Methyl-5-tert-butylfuran-2-carboxamide XXII.
Acyl chloride XXI, 5.1 g, was dissolved in 5 ml of
acetonitrile, and this solution was added in one por-
tion with vigorous stirring to 25 ml of 25% aqueous
ammonia. The resulting mixture was stirred for
30 min; the precipitate that formed was filtered off
and dried in air. Yield 4.3 g, mp 149 150 C.
3-Methyl-5-tert-butyl-2-cyanofuran XXIII.
Amide XXII, 3.6 g, was suspended in 10 ml of ben-
zene, and 4.2 g of finely ground phosphorus penta-
chloride was added in several portions. The reaction
mixture was refluxed for 4 h and distilled in a vacuum.
The fraction with bp 70 121 C (1 mm) was collected.
It was dissolved in 10 ml of benzene, 2 ml of triethyl-
amine was added, and the mixture was stirred for 2 h.
Triethylamine hydrochloride was filtered off, and the
filtrate was distilled in a vacuum to give 1.6 g of
3-Methoxymethyl-5-tert-butyl-2-acetylfuran
XXIX. Magnesium turnings, 0.7 g, were treated with
3 ml of absolute ethanol, a small crystal of iodine was
added, and after the start of the reaction a solution of
5 ml of diethyl malonate in 10 ml of anhydrous
ethanol was added. After the completion of the vig-
orous reaction, the mixture was stirred for 15 min at
60 70 C and cooled; 20 ml of ether were added. After
that, a solution of 6.2 g of acyl chloride XXVIII in
10 ml of anhydrous ether was added dropwise with
stirring. The reaction mixture was stirred for 2 g at
room temperature and left overnight. Then the mixture
was treated with dilute hydrochloric acid, the ether
layer was separated, and the aqueous layer was ex-
tracted with ether. The combined extracts were dried
over calcium chloride, the ether was distilled off, and
the residue was dissolved in 20 ml of acetic acid. The
solution was treated with 6 ml of hydrochloric acid,
and the resulting mixture was refluxed with stirring
for 6 h. After that, the reaction mixture was treated
with water, extracted with ether, dried over calcium
chloride, and distilled in a vacuum to give 3.6 g of
1
cyanofuran XXIII, bp 84 86 C (1 mm). H NMR
spectrum (CCl4), , ppm: 1.12 s [(CH3)3C], 2.07 s
(CH3-furan), 5.82 m (H4-furan).
3-Bromomethyl-5-tert-butyl-2-cyanofuran
XXIV. Nitrile XXIII, 1.6 g, was dissolved in 15 ml
of carbon tetrachloride, 1.7 g of N-bromosuccinimide
and 0.2 g of azobis(isobutyronitrile) were added in
one portion, and the resulting mixture was refluxed
for 2 h. After the disappearance of traces of N-bromo-
succinimide, the reaction mixture was left overnight.
After that, succinimide was filtered off, and the filtrate
was distilled in a vacuum to give 1.3 g of bromide
1
XXIV, bp 105 C (1 mm). H NMR spectrum (CCl4),
1
ketone XXIX, bp 84 86 C (1 mm). H NMR spec-
, ppm: 1.32 s [(CH3)3C], 4.24 s (CH2Br), 6.09 s
(H4-furan).
trum (CCl4), , ppm: 1.21 s [(CH3)3C], 2.24 s
(CH3CO), 3.24 s (CH3OC), 4.44 s (CH2O-furan),
6.15 s (H4-furan).
Methyl 3-methoxymethyl-5-tert-butylfuran-2-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 11 2003