Chemistry of Heterocyclic Compounds 2018, 54(9), 832–839
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mp 200–202°С. H NMR spectrum, δ, ppm (J, Hz): 2.31
(3H, s, 6-CH3); 3.80 (3H, s) and 3.82 (3H, s, 3',4'-OCH3);
6.42 (1H, s, H-5); 6.66 (1H, s, Н-7); 6.67 (1H, s, =CHAr);
7.03 (1H, d, J = 8.4, H-5'); 7.49 (1H, dd, J = 8.4, J = 2.0,
H-6'); 7.53 (1H, d, J = 2.0, H-2'); 10.92 (1H, br. s, 4-ОН).
13C NMR spectrum (125 MHz), δ, ppm: 22.1; 55.4; 55.5;
103.2; 107.3; 110.3; 111.0; 111.9; 113.9; 124.9; 145.8;
148.7; 150.0; 150.2; 156.5; 166.0; 180.5. Mass spectrum, m/z
(Irel, %): 313 [M+H]+ (100). Found, %: C 69.03; H 5.40.
C18H16O5. Calculated, %: C 69.22; H 5.16.
2.60 (3H, s, 4-CH3); 3.87 (2H, s, 7-СH2); 3.95 (3H, s) and
3.99 (3H, s, 3',4'-OCH3); 6.41 (1H, s, H-5); 6.69 (1H, s,
=CHAr); 6.95 (1H, d, J = 8.4, H-5'); 7.41 (1H, dd, J = 8.4,
J = 2.0, H-6'); 7.50 (1H, d, J = 2.0, H-2'). 13C NMR
spectrum (100 MHz), δ, ppm: 18.0; 44.8; 55.0; 55.8; 56.0;
102.0; 110.7; 111.3; 112.1; 113.5; 114.1; 125.2; 125.9;
140.8; 147.3; 149.0; 150.3; 165.4; 166.6; 183.3. Mass
spectrum, m/z (Irel, %): 370 [M+H]+ (100). Found, %:
C 68.53; H 6.39; N 3.52. C21H23NO5. Calculated, %:
C 68.28; H 6.28; N 3.79.
(Z)-4-Hydroxy-6-methyl-2-(3,4,5-trimethoxybenzyl-
idene)benzofuran-3(2H)-one (6d). Yield 2.88 g (84%),
yellow crystals, mp 195–197°С. 1H NMR spectrum, δ, ppm:
2.31 (3H, s, 6-CH3); 3.72 (3H, s, 4'-OCH3); 3.83 (6H, s,
3',5'-OCH3); 6.42 (1H, s, H-5); 6.64 (1H, s, H-7); 6.67 (1H,
s, =CHAr); 7.25 (2H, s, H-2',6'); 10.96 (1H, br. s, 4-ОН).
13C NMR spectrum (100 MHz), δ, ppm: 22.1; 55.9; 60.1;
103.2; 107.1; 108.5; 109.9; 111.2; 127.7; 138.9; 146.4;
150.2; 152.9; 156.6; 166.1; 180.6. Mass spectrum, m/z
(Irel, %): 343 [M+H]+ (100). Found, %: C 66.48; H 5.22.
C19H18O6. Calculated, %: C 66.66; H 5.30.
Synthesis of 7-aminomethyl-6-hydroxy-4-methyl-
aurones 7a–c, 8a–c, 9a–c, and 10a–d (General method).
The respective aminal (2.2 mmol) was added to a hot
solution of 6-hydroxy-4-methylaurone 5a–d (2 mmol) in
i-PrOH (15 ml), and the mixture was heated under reflux
for 3–5 h. The completion of the reaction was determined by
TLC. The reaction mixture was cooled, diluted with hexane
(15–20 ml), the formed precipitate filtered off and
recrystallized from a mixture of i-PrOH–hexane, 1:2.
(Z)-2-Benzylidene-7-[(dimethylamino)methyl]-6-hydroxy-
4-methylbenzofuran-3(2H)-one (7a). Yield 483 mg (78%),
yellow crystals, mp 188–190°С. 1H NMR spectrum, δ, ppm
(J, Hz): 2.45 (6H, s, N(СН3)2); 2.58 (3H, s, 4-CH3); 3.89
(2H, s, 7-СH2); 6.40 (1H, s, H-5); 6.71 (1H, s, =CHAr);
7.33–7.49 (3H, m, H-3',4',5'); 7.82 (2H, d, J = 7.3, H-2',6');
10.74 (1H, br. s, 6-ОН). 13C NMR spectrum (100 MHz),
δ, ppm: 18.0; 44.6; 54.9; 102.1; 110.2; 111.9; 114.3; 128.9;
129.3; 131.1; 133.0; 140.9; 148.3; 165.8; 167.1; 183.5.
Mass spectrum, m/z (Irel, %): 310 [M+H]+ (100). Found, %:
C 73.65; H 6.45; N 4.79. C19H19NO3. Calculated, %:
C 73.77; H 6.19; N 4.53.
(Z)-7-[(Dimethylamino)methyl]-6-hydroxy-2-(4-meth-
oxybenzylidene)-4-methylbenzofuran-3(2H)-one (7b).
Yield 597 mg (88%), yellow crystals, mp 180–182°С.
1H NMR spectrum, δ, ppm (J, Hz): 2.44 (6H, s, N(СН3)2);
2.58 (3H, s, 4-CH3); 3.85 (3H, s, 4'-OCH3); 3.88 (2H, s,
7-СH2); 6.39 (1H, s, H-5); 6.68 (1H, s, =CHAr); 6.97 (2H,
d, J = 8.8, H-3',5'); 7.77 (2H, d, J = 8.8, H-2',6'); 10.79 (1H,
br. s, 6-ОН). 13C NMR spectrum (125 MHz), δ, ppm: 18.0;
44.7; 55.0; 55.5; 102.1; 110.5; 112.2; 114.1; 114.5; 125.6;
132.8; 140.7; 147.2; 160.5; 165.5; 166.7; 183.4. Mass
spectrum, m/z (Irel, %): 340 [M+H]+ (100). Found, %: C 70.52;
H 6.07; N 3.91. C20H21NO4. Calculated, %: C 70.78;
H 6.24; N 4.13.
(Z)-2-Benzylidene-6-hydroxy-4-methyl-7-(pyrrolidin-
1-ylmethyl)benzofuran-3(2H)-one (8a). Yield 389 mg
(58%), yellow crystals, mp 198–201°С. 1H NMR spectrum,
δ, ppm (J, Hz): 1.81–2.06 (4H, m, 3,4-СН2 pyrrolidine);
2.58 (3H, s, 4-CH3); 2.71–2.92 (4H, m, 2,5-СН2
pyrrolidine); 4.09 (2H, s, 7-СH2); 6.39 (1H, s, H-5); 6.71
(1H, s, =CHAr); 7.32–7.56 (3H, m, H-3',4',5'); 7.82 (2H, d,
J = 7.3, H-2',6'); 9.74 (1H, br. s, 6-ОН). 13C NMR spectrum
(100 MHz), δ, ppm: 18.0; 23.9; 51.0; 53.8; 102.5; 110.1;
111.7; 114.4; 128.9; 129.2; 131.1; 133.0; 140.9; 148.4;
165.5; 167.5; 183.5. Mass spectrum, m/z (Irel, %): 336 [M+H]+
(100). Found, %: C 75.11; H 6.23; N 4.43. C21H21NO3.
Calculated, %: C 75.20; H 6.31; N 4.18.
(Z)-6-Hydroxy-2-(4-methoxybenzylidene)-4-methyl-
7-(pyrrolidin-1-ylmethyl)benzofuran-3(2H)-one
(8b).
Yield 490 mg (67%), yellow crystals, mp 168–170°С.
1H NMR spectrum, δ, ppm (J, Hz): 1.85–1.96 (4H, m,
3,4-СН2 pyrrolidine); 2.58 (3H, s, 4-CH3); 2.70–2.87 (4H,
m, 2,5-СН2 pyrrolidine); 3.85 (3H, s, 4'-OCH3); 4.08 (2H,
s, 7-СH2); 6.38 (1H, s, H-5); 6.68 (1H, s, =CHAr); 6.96
(2H, d, J = 8.6, H-3',5'); 7.77 (2H, d, J = 8.6, H-2',6'); 8.14
(1H, br. s, 6-ОН). 13C NMR spectrum (100 MHz), δ, ppm:
18.0; 23.9; 51.0; 53.8; 55.5; 102.4; 110.4; 112.0; 114.2;
114.5; 125.7; 132.8; 140.6; 147.3; 160.5; 165.2; 167.1;
183.4. Mass spectrum, m/z (Irel, %): 366 [M+H]+ (100). Found,
%: C 72.08; H 6.55; N 3.97. C22H23NO4. Calculated, %:
C 72.31; H 6.34; N 3.83.
(Z)-6-Hydroxy-4-methyl-7-(pyrrolidin-1-ylmethyl)-
2-(3,4,5-trimethoxybenzylidene)benzofuran-3(2H)-one
(8c). Yield 545 mg (64%), yellow crystals, mp 180–182°С.
1H NMR spectrum, δ, ppm: 1.83–1.94 (4H, m, 3,4-СН2
pyrrolidine); 2.55 (3H, s, 4-CH3); 2.64–2.77 (4H, m,
2,5-СН2 pyrrolidine); 3.88 (3H, s, 4'-OCH3); 3.91 (6H, s,
3',5'-OCH3); 3.99 (2H, s, 7-СH2); 6.36 (1H, s, H-5); 6.58
(1H, s, =CHAr); 7.09 (2H, s, H-2',6'); 11.40 (1H, br. s,
6-ОН). 13C NMR spectrum (100 MHz), δ, ppm: 17.9; 23.7;
51.0; 54.1; 56.0; 61.0; 102.5; 108.3; 110.3; 111.8; 114.2;
128.3; 139.3; 140.7; 147.9; 153.2; 165.1; 166.9; 183.1.
Mass spectrum, m/z (Irel, %): 426 [M+H]+ (100). Found, %:
C 67.61; H 6.38; N 3.47. C24H27NO6. Calculated, %:
C 67.75; H 6.40; N 3.29.
(Z)-2-Benzylidene-6-hydroxy-4-methyl-7-[(4-methyl-
piperazin-1-yl)methyl]benzofuran-3(2H)-one (9a). Yield
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488 mg (67%), yellow crystals, mp 195–197 °С. H NMR
spectrum, δ, ppm: 2.31 (3H, s, NCH3); 2.37–3.03 (11H, m,
4-CH3, H piperazine); 3.92 (2H, s, 7-СH2); 6.38 (1H, s,
H-5); 6.69 (1H, s, =CHAr); 7.31–7.53 (3H, m, H-3',4',5');
7.74–7.87 (2H, m, H-2',6'); 11.21 (1H, br. s, 6-ОН).
13C NMR spectrum (100 MHz), δ, ppm: 18.0; 45.9; 52.7;
(Z)-2-(3,4-Dimethoxybenzylidene)-7-[(dimethylamino)-
methyl]-6-hydroxy-4-methylbenzofuran-3(2H)-one (7c).
Yield 665 mg (90%), yellow crystals, mp 165–167°С.
1H NMR spectrum, δ, ppm (J, Hz): 2.43 (6H, s, N(СН3)2);
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