1088
PEVZNER
[(CH3)3C + CH3-ethyl], 1.89 s (CH3CO), 2.44 s (CH3-
furan), 4.14 q (CH2O-ethyl), 5.05 s (OCH2-furan).
NMR spectrum, , ppm: 1.31 s [(CH3)3C], 2.31 s
(CH3-furan), 4.39 s (CH2Cl).
Ethyl 2-methyl-4-(diethoxyphosphorylmethyl)-5-
tert-butylfuran-3-carboxylate XI. A solution of
4.0 g of III in 5 ml of benzene was added at 75 C to
a solution of sodium diethyl phosphite obtained from
0.4 g of sodium and 2.5 ml of diethyl hydrogen phos-
phite in 20 ml of benzene. The reaction mixture was
refluxed with stirring for 13 h, the sodium chloride
precipitate was separated by centrifugation, the sol-
vent was distilled off at reduced pressure, and the res-
idue was vacuum-distilled. Phosphonate XI, 3.2 g
2-Methyl-4-hydroxymethyl-5-tert-butylfuran-3-
carboxylic acid VII. Ester VI (5.6 g), 10 ml of
ethanol, and a solution of 5 g of KOH in 15 ml of
water were mixed and refluxed with vigorous stirring
for 4 h. The resulting homogeneous clear solution was
acidified to pH 2. The precipitate was filtered off,
washed with water, and dried. Yield of hydroxymeth-
ylated acid VII 3.4 g, mp 93 94 C.
2-Methyl-4-chloromethyl-5-tert-butylfuran-3-
carboxylic acid chloride VIII. A mixture of 2.5 g of
acid VII, 3.4 g of thionyl chloride, 0.2 ml of dimeth-
ylformamide, and 20 ml of benzene was refluxed for
7 h. The solvent and excess thionyl chloride were re-
moved at reduced pressure, and the residue was vac-
uum-distilled to give 2.2 g of chloride VIII, bp 117
118 C/1 mm Hg.
1
(57%), was obtained, bp 159 160 C/1 mm Hg. H
NMR spectrum, , ppm: 1.22 t (CH3-ethyl, JHH 7 Hz),
1.32 s [(CH3)3C], 2.42 s (CH3-furan), 3.30 d (CH2P,
JHP 20 Hz), 3.77 4.20 m (CH2OP + CH2OOC).
2-Methyl-3-acetyl-4-(diethoxyphosphorylmeth-
yl)-5-tert-butylfuran XII. A mixture of 2.6 g of II
and its chloromethyl derivative IV was added with
stirring at 80 C to a solution of sodium diethyl phos-
phite prepared from 0.26 g of sodium and 2 ml of
diethyl hydrogen phosphite in 20 ml of benzene.
The resulting mixture was stirred for 8 h, the sodium
chloride was separated by centrifugation, the solvent
was distilled off at reduced pressure, and the residue
was vacuum-distilled. Phosphonate XII, 1.6 g (66%),
was obtained, bp 168 171 C/1 mm Hg. 1H NMR
spectrum, , ppm: 1.23 m [(CH3)3C + CH3-ethyl],
2.28 s (CH3CO), 2.44 s (CH3-furan), 3.28 d (CH2P,
JHP 20 Hz), 3.86 m (CH2OP, JHH 7 Hz, JHP 11 Hz).
N,N-Diethyl-2-methyl-4-chloromethyl-5-tert-bu-
tylfuran-3-carboxamide V. A solution of 1.9 g of
diethylamine in 5 ml of benzene was added at 20
25 C with vigorous stirring to a solution of 2.2 g of
chloride VIII in 10 ml of benzene. The reaction mix-
ture was left overnight, diethylamine hydrochloride
was filtered off, the solvent was removed at reduced
pressure, and the residue was vacuum-distilled to give
16 g (64%) of chloromethyl amide V, bp 146 148 C/
1
1 mm Hg. H NMR spectrum, , ppm: 0.73 t (CH3-
ethyl, JHH 7 Hz), 1.31 s [(CH3)3C], 2.11 s (CH3-
furan), 3.34 q (CH2N, JHH 7 Hz), 4.64 s (CH2Cl).
2-Methyl-4-(diethoxyphosphorylmethyl)-5-tert-
butylfuran-3-diethylcarboxamide XIII. To a solu-
tion of sodium diethyl phosphite prepared from 0.13 g
of sodium and 1.2 ml of diethyl hydrogen phosphite
in 8 ml of benzene, a solution of 1.6 g of chlorometh-
ylamide V in 4 ml of benzene was added at 80 C.
The resulting mixture was refluxed with stirring for
17 h, the sodium chloride precipitate was separated
by centrifugation, the solvent was distilled off at re-
duced pressure, and the residue was vacuum-distilled.
Phosphonate XIII, 1.2 g (57%), was obtained, bp
2-Methyl-4-chloromethyl-5-tert-butylfuran-3-car-
boxamide X. To a solution of 6 g of VIII in 30 ml
of dioxane, 10 ml of 25% aqueous ammonia was
added dropwise with stirring at 12 14 C. The result-
ing mixture was kept at this temperature for 30 min
and diluted with ice-cold water. An abundant pre-
cipitate formed, which was filtered off, washed with
a small amount of water, and dried. Carboxamide X,
1
5.3 g (96%), was obtained, mp 159 160 C. H NMR
spectrum, , ppm: 1.30 s [(CH3)3C], 2.41 s (CH3-
furan), 4.59 s, 4.78 s (both ClCH2-furan, intensity
ratio 1 : 4.6), 6.05 br.s (NH2).
1
181 C/1 mm Hg. H NMR spectrum, , ppm: 1.19 m
(CH3-ethyl), 1.31 s [(CH3)3C], 2.13 s (CH3-furan),
3.04 br.d (CH2P, JHP 20 Hz), 3.34 m (NCH2, JHH
7 Hz), 3.88 m (CH2OP. JHH 7 Hz, JHP 10 Hz).
2-Methyl-4-chloromethyl-5-tert-butylfuran-3-car-
bonitrile IX. To a suspension of 4.4 g of X in 20 ml
of benzene, 4 g of phosphorus pentachloride was
added in three or four portions. The amide quickly
dissolved with heat evolution. The resulting solution
was refluxed for 4 h and vacuum-distilled. Nitrile IX,
2-Methyl-4-(diethoxyphosphorylmethyl)-5-tert-
butylfuran-3-carbonitrile XV. A solution of 3.1 g
of nitrile in 4 ml of benzene was added at 80 C to
a solution of sodium diethyl phosphite prepared from
0.34 g of sodium and 2.2 ml of diethyl hydrogen
1
3.1 g (76%), was obtained, bp 104 C/1 mm Hg. H
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 7 2002