Chemical Papers
CH2C6H5), 48.5 (d, C-3, 1JCP =131.5 Hz), 63.0 (d, POCH2,
116.3 (C-8), 120.5 (C-4a), 124.6 (C-6), 127.9 (C-5), 128.3
(C-7), 151.8 (C-8a), 166.5 (C=O, C-2), 170.4 (d, COOCH3,
3JCCCP = 20.4 Hz). MS: m/z (%) = 356 (M + H)+ (18), 283
(32), 220 (57), 188 (41), 159 (47), 138 (47), 131 (100), 111
(94), 82 (39), 32 (72), 28 (87). Found C 53.99; 6.05 requires
C 53.93; H 5.94%.
2
2JCOP = 7.2 Hz), 63.8 (d, POCH2, JCOP = 7.4 Hz), 115.9
(C-8), 120.9 (C-4a), 124.5 (C-6), 127.4 (C-4`), 128.1
(C-3`,C-5`), 128.1 (C-2`, C-6`), 128.4 (C-5), 130.9 (C-7),
3
135.2 (d, C-1`, JCCCP = 12.5 Hz), 151.4 (C-8a), 166.8
(C=O, C-2). MS: m/z (%)=375 (M+H)+ (25), 283 (82),
255 (47), 237 (59), 227 (65), 209 (48), 159 (59), 131 (55),
111 (55), 91 (93), 65 (71), 43 (62), 32 (83), 29 (99), 28
(100). Found C 64.36; H 6.11 requires C 64.17; H 6.19%.
Diethyl 3-allyl-2-oxo-3,4-dihydro-2H-chromen-3-ylphos-
phonate 2d. Yields: Method C 0.14 g (43%); Method D1
0.17 g (52%); Method D2 0.165 g (51%); Method D3
0.16 g (49%); Colorful oil. IR (CHCl3): ν = 1765, 1050,
Ethyl [3-(diethoxyphosphoryl)-2-oxo-3,4-dihydro-
2H-chromen]-3-acetate 2f. Yields: Method C 0.17 g
(46%); Method D1 0.10 g (27%); Method D2 0.11 g (30%);
Method D3 0.12 g (32%), mp=56–58 °C (n-hexane/diethyl
1
ether). IR (CHCl3): ν = 1765, 1750, 1055, 1030 cm−1. H
NMR (300 MHz) (CDCl3): δ = 0.93 (t, 3H, POCH2CH3,
3JHH =7.1 Hz), 1.26 (t, 3H, COOCH2CH3, 3JHH =7.1 Hz),
1
3
1025 cm−1. H NMR (300 MHz) (CDCl3): δ = 0.98 (td,
1.30 (t, 3H, POCH2CH3, JHH = 7.1 Hz), 2.80 (dd, 1H,
3
4
3H, POCH2CH3, JHH = 7.1, JHP = 0.5 Hz), 1.31 (td, 3H,
CHAHBCOOC2H5, 2JHH =17.3, 3JHCCP =5.3 Hz), 3.30–3.88
(m, 5H, 4-CH2, CHAHBCOOC2H5, POCH2CH3), 4.07–4.19
(m, 4H, COOCH2CH3, POCH2CH3), 7.01–7.11 (m, 2H, H-8,
H-6), 7.17-7.27 (m, 2H, H-5, H-7). 13C NMR (75.4 MHz)
(CDCl3): δ = 14.1 (COOCH2CH3), 15.9 (d, CH3CH2OP,
3
4
POCH2CH3, JHH = 7.1, JHP = 0.5 Hz), 2.62 (dddt, 1H,
CHAHBCH=CH2, 2JHH =14.0, 3JHH =8.6, 4JHCCP =0.8 Hz),
3.05 (dddt, 1H, CHAHBCH=CH2, 2JHH =13.9, 3JHH =6.0,
4JHCCP = 1.4 Hz), 3.22 (dd, 2H, 4-CH2, JHH = 17.7,
2
3JHCCP =27.0 Hz), 3.54 (ddq, 1H, POCHAHBCH3, 2JHH =7.1,
2JHH =10.1, 3JHCCP =9.2 Hz), 3.86 (ddq, 1H, POCHAHBCH3,
3JCCOP = 6.8 Hz), 16.3 (d, CH3CH2OP, JCCOP = 4.5 Hz),
3
30.4 (d, 4-CH2, 2JCCP =6.8 Hz), 37.1 (s, CH2COOCH2CH3),
45.2 (d, C-3, 1JCP =131.1 Hz), 61.3 (s, CH2COOCH2CH3),
2JHH = 7.1, JHH = 10.1, JHCCP = 14.1 Hz), 4.08–4.20
(m, 2H, POCH2CH3), 5.19 (m, 2H, CH2-CH = CH2),
5.83 (m, 1H, CH2-CH = CH2), 7.02 (dd, 1H, H-8, J = 7.0,
J=0.8 Hz), 7.07–7.12 (ddd, 1H, H-6, J=7.5, J=1.1 Hz),
7.20–7.28 (m, 2H, H-5, H-7). 13C NMR (75.4 MHz)
2
3
2
63.5 (d, POCH2, JCOP = 6.8 Hz), 63.9 (d, POCH2,
2JCOP = 9.0 Hz), 116.3 (C-8), 120.6 (C-4a), 124.5 (C-6),
127.9 (C-5), 128.2 (C-7), 151.8 (C-8a), 166.8 (C = O,
C-2), 169.9 (d, COOCH2CH3, 3JCCCP =18.1 Hz). MS: m/z
(%)=371 (M+H)+ (17), 325 (26), 283 (66), 234 (58), 188
(60), 160 (60), 138 (43), 131 (72), 111 (80), 82 (41), 32
(74), 29 (90), 28 (100). Found C 55.21; H 6.09 required C
55.14; H 6.26%,
3
(CDCl3): δ = 16.0 (d, CH3CH2OP, JCCOP = 6.8 Hz), 16.3
(d, CH3CH2OP, 3JCCOP =6.8 Hz), 29.8 (s, 4-CH2), 37.2 (s,
1
CH2CH = CH2), 46.6 (d, C-3, JCP = 130.1 Hz), 63.0 (d,
POCH2, 2JCOP =6.8 Hz), 63.7 (d, POCH2, 2JCOP =9.0 Hz),
116.0 (C-8), 120.6 (s, CH2CH = CH2), 120.8 (d, C-4a,
2JCCP =3.2 Hz), 124.6 (C-6), 128.2 (C-5), 128.3 (C-7), 131.8
(d, CH2CH=CH2, J=11.3 Hz), 151.7 (C-8a), 166.6 (C=O,
C-2). MS: m/z (%)=325 (M+H)+ (25), 324 (26), 285 (39),
255 (100), 209 (94), 188 (51), 159 (58), 138 (43), 131 (67),
111 (98), 91 (53), 81 (65), 41 (68), 28 (97). Found C 59.54;
H 6.50 requires C 59.26; H 6.53%.
Compound 3,4-dihydrocoumarin 3a was also isolated
with the corresponding yields as shown in Table 2.
One‑pot hydrogenation/alkylation of ethyl 3‑carboxycou‑
marin 1b with NaBH4 and methyl iodide Method: To a
stirred solution of ethyl 3-carboxycoumarin 1b (1 mmol)
in dry pyridine (1.5 mL), NaBH4 (1.1 mmol, 0.04 g) was
added. The stirring continued for 5 min at room temperature
and the mixture was cooled down in an ice bath. Methyl
iodide (8 mmol) was dropped in three portions for 10 min
and after 2 h the reaction mixture was quenched onto 2 N
HCl (10 mL) containing crushed ice. The resulted emulsion
was extracted with dichloromethane (3×20 mL), dried with
Na2SO4 and after solvent evaporation the product was puri-
fed by column chromatography using n-hexane and ethyl
acetate with increasing polarity.
Methyl [3-(diethoxyphosphoryl)-2-oxo-3,4-dihydro-
2H-chromen]-3-acetate 2e. Yields: Method C 0.06 g (17%);
Method D2 0.105 g (29%); Method D3 0.09 g (25%); Method
E1 0.11 g (31%), mp = 83-85 °C (n-hexane/diethyl ether).
1
IR (CCl4): ν = 1770, 1755, 1255, 1050, 1025 cm−1. H
NMR (300 MHz) (CDCl3): δ = 0.93 (t, 3H, POCH2CH3,
3JHH =7.1 Hz), 1.30 (t, 3H, POCH2CH3, 3JHH =7.1 Hz), 2.82
2
3
(dd, 1H, CHAHBCOOCH3, JHH = 17.4, JHCCP = 5.3 Hz),
3.30–3.86 (m, 5H, 4-CH2, CHAHBCOOCH3, POCH2CH3),
3.70 (s, 3H, COOCH3), 4.06–4.16 (m, 2H, POCH2CH3),
7.01–7.12 (m, 2H, aromatic), 7.17–7.27 (m, 2H, aromatic).
13C NMR (75.4 MHz) (CDCl3): δ = 15.9 (d, CH3CH2OP,
Ethyl 3-methyl-2-oxo-3,4-dihydro-2H-chromen-3-car-
boxylate 2b. Yields: 0.17 g (73%). Colorless oil. IR (CCl4):
ν=1795, 1755 cm−1. 1H NMR (300 MHz) (CDCl3): δ=1.00
(t, 3H, COOCH2CH32, 3JHH =7.1 Hz), 1.63 (s, 3H, CH3-3),
2.98 (d, 1H, CHA-4 JHH = 15.9 Hz), 3.37 (d, 1H, CHB-4
2JHH = 15.9 Hz), 3.94–4.14 (m, 2H, COOCH2), 7.04–7.28
(m, 4H, aromatic). 13C NMR (75.4 MHz) (CDCl3): δ=13.7
3
3JCCOP = 4.5 Hz), 16.3 (d, CH3CH2OP, JCCOP = 4.5 Hz),
2
30.4 (d, 4-CH2, JCCP = 6.8 Hz), 37.1 (s, CH2COOCH3),
45.2 (d, C-3, 1JCP =131.1 Hz), 52.2 (s, COOCH3), 63.5 (d,
POCH2, 2JCOP =6.8 Hz), 63.9 (d, POCH2, 2JCOP =9.0 Hz),
1 3