Med Chem Res
1
3
extracted with ethyl acetate (3 9 15 mL). The combined
(d, J = 9.6 Hz, 1H), 5.53 (s, 2H); C NMR (CDCl3,
100 MHz): d 160.5, 148.2, 146.7, 144.4, 143.5, 136.7, 131.
3, 128.8, 128.4, 128.3, 128.1, 126.6, 116.4, 114.6, 113.9,
organic layers were dried over anhydrous Na SO .
2
4
The solvent was removed, and the residue was purified by
flash chromatography to yield 7. The reactions using
allyl chloride (163 lL, 2 mmol), 1-chloro-2-methylpro-
pane (222 lL, 2 mmol), benzyl alcohol (230 lL, 2 mmol),
and 1-naphthyl chloride (325 mg, 2 mmol) as alkyl halide
yielded compounds 8, 9, 10, and 11, respectively.
?
113.5, 106.7, 75.2; CIMS m/z 293 [M?1] .
9-Naphthyloxy-7H-furo[3,2-g][1]benzopyran-7-one (11) Yield:
73 %; mp 147–148 °C; UV (CHCl ): k
(log e) 256 (4.
2961, 1722, 1625, 1582,
3
max
33), 301 (3.88); IR (neat): m
1
max
1
460, 1431, 1288; H NMR (400 MHz, CDCl ): d, 8.77 (d,
3
9
-Methoxy-7H-furo[3,2-g][1]benzopyran-7-one (7) Yield:
5 %; cream colored crystalline solid, mp 140–141 °C
J = 7.2 Hz, 1H), 8.88 (d, J = 8.6 Hz, 1H), 8.11 (d, J = 8.
0 Hz, 1H), 7.91 (d, J = 8.0 Hz, 1H), 7.88 (d, J = 9.6 Hz,
1H), 7.72 (d, J = 2.0 Hz, 1H), 7.45–7.65 (m, 4H), 6.83 (d,
8
(
Lit. (Kilic et al., 2006) 140–142 °C); UV (CHCl ): kmax
3
1
3
(
log e) 252 (3.82), 298 (3.55); IR (neat): m
1717, 1587,
J = 2.0 Hz, 1H), 6.42 (d, J = 9.6 Hz, 1H); C NMR
max
1
1
1
7
1
2
1
7
401, 1260, 1275, cm ; H NMR (CDCl , 400 MHz): d 7.
7 (d, J = 7.2 Hz, 1H), 7.69 (d, J = 2.1 Hz, 1H), 7.35 (s,
(CDCl , 100 MHz): 164.0, 148.7, 147.3, 144.1, 144.0, 135.
3
3
5, 132.1, 131.9, 128.8, 128.4, 126.7, 125.8, 125.6, 124.8,
H), 6.82 (d, J = 2.1 Hz, 1H), 6.36 (d, J = 7.2 Hz, 1H), 4.
3
9 (s, 3H); C NMR (CDCl , 100 MHz): d 160.5, 147.6,
46.6, 144.4, 142.9, 132.7, 126.1, 116.5, 114.7, 112.9, 106.
?
, 61.3. CIMS m/z 217 [M?1]
124.6, 124.4, 123.2, 117.0, 116.4, 115.0, 106.9; CIMS m/
?
z 329 [M?1] .
1
3
General method for synthesis of O-acylated analogs
(
12 and 13)
9
-(2-Propen-1-yloxy)-7H-furo[3,2-g][1]benzopyran-7-one
(
8) Yield: 86 %; mp 82–83 °C [lit. (Li et al., 2011)
A mixture of xanthotaxol (6) (202 mg, 1 mmol), pyridine
(40 lL, 0.5 mmol), 1-naphthoyl chloride (180 lL,
1.2 mmol) for compound 12, and anhydrous dichlorometh-
ane (5 mL) was stirred under nitrogen atmosphere and
refluxed for 3 h. Reaction was monitored by TLC until the
starting material fully reacted. After cooling to room tem-
perature, the reaction mixture was filtered and washed with
acetone. The solvent was removed on a rotary evaporator,
and the crude product was purified by flash chromatography
to give 12. Similar reaction using 2-mercaptobenzoyl chlo-
ride (206 mg, 1.2 mmol) gave compound 13.
8
0–81 °C]; UV (CHCl ): k
(log e) 254 (3.89), 302 (3.
3
max
9
1
0); IR (neat):mmmax 1725, 1623, 1586, 1465, 1400, 1292;
H NMR (400 MHz, CDCl ) d 7.77 (d, J = 9.6 Hz, 1H), 7.
3
6
9 (d, J = 2.4 Hz, 1H), 7.37 (s, 1H), 6.82 (d, J = 2.4 Hz,
H), 6.37 (d, J = 9.6 Hz, 1H), 6.15 (m, 1H), 5.43 (dd, J =
.5 Hz, J = 17 Hz, 1H), 5.20 (dd, J = 1.2 Hz, J = 10.
1
1
3
1
3
2
1
3
Hz, 1H), 5.02 (d, J = 3.6 Hz, 2H); C NMR (CDCl3,
00 MHz): d 160.5, 148.3, 146.6, 144.4, 143.5, 133.3, 131.
, 125.9, 118.9, 116.5, 114.7, 113.4, 106.8, 74.3; CIMS m/z
?
43.2 [M?1]
9
-Naphthoyloxy-7H-furo[3,2-g][1]benzopyran-7-one
9
-(3-Methylpropoxy)-7H-furo[3,2-g][1]benzopyran-7-one
(
12) Yield: 91 %; mp 162–163 °C; UV (CHCl ): k
log e) 245 (4.31), 303 (4.08); IR (neat): mmax1730, 1674,
3
max
(
9) (IP N.Y.-Y. et al., 2011) Yield: 87 %; mp 155–
56 °C; UV (CHCl ): k (log e) 252 (4.41), 301 (4.24);
(
1
3
max
-1 1
1
592, 1512, 1259, 1147, 1061 cm ; H NMR (400 MHz,
): d 9.07 (d, J = 8.4 Hz, 1H), 8.70 (d, J = 7.2 Hz,
H), 8.16 (d, J = 8.0 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H), 7.
2 (d, J = 9.6 Hz, 1H), 7.71 (d, J = 2.0 Hz, 1H), 7.55–7.
IR (neat): m
2960, 1728, 1626, 1588, 1466, 1440, 1293;
max
1
CDCl
3
H NMR (400 MHz, CDCl ) d 7.76 (d, J = 9.6 Hz, 1H), 7.
3
1
8
6
8 (d, J = 2.4 Hz, 1H), 7.34 (s, 1H), 6.81 (d, J = 2.4 Hz,
1
1
1
9
H), 6.36 (d, J = 9.6 Hz, 1H), 4.25 (d, J = 6.8 Hz, 2H) 2.
1
7 (m, 1H), 1.10 (d, J = 6.8 Hz, 6H); C NMR (CDCl3,
3
70 (m, 4H), 6.89 (d, J = 2.0 Hz, 1H), 6.40 (d, J = 9.6 Hz,
13
H); C NMR (CDCl , 100 MHz): 164.0, 159.8, 148.5,
1
1
3
00 MHz): d 160.6, 148.1, 146.6, 144.3, 143.4, 132.3, 125.
, 116.5, 114.7, 112.8, 106.7, 80.4, 29.1, 19.0 CIMS m/
47.4, 144.2, 144.0, 135.5, 132.3, 131.9, 128.8, 128.5, 126.
?
3, 125.4, 125.8, 124.5, 124.5, 124.5, 123.3, 117.1, 116.1,
?
14.0, 106.8; CIMS m/z 357 [M?1] ; Anal. Calcd for
z 259.1 [M?1] .
1
C H O : C, 74.16; H, 3.39; Found: C, 74.09; H, 3.29.
22 12 5
9
-(Phenylmethoxy)-7H-furo[3,2-g][1]benzopyran-7-one
(
10) Yield: 71 %; mp 117–118 °C [lit. (Deng et al.,
9-(2-Thienoyloxy)-7H-furo[3,2-g][1]benzopyran-7-one
2
2
1
6
1
010) 120–122 °C]; UV (CHCl ): k
(log e) 255 (4.44),
2961, 1722, 1625, 1582, 1460,
(13) Yield: 83 %; mp 188–189 °C; UV (CHCl ): k
3
max
3
max
99 (4.12); IR (neat): m
431, 1288; H NMR (400 MHz, CDCl ): d 7.72 (d, J = 9.
(log e) 250 (4.55), 282 (4.39); IR (neat): m
1412, 1260, 1275, 1142, 1082 cm ; H NMR (400 MHz,
1735, 1638,
max
max
1
-1 1
3
Hz, 1H), 7.67 (d, J = 2.4 Hz, 1H), 7.56 (s, 1H), 7.55 (s,
CDCl ) d 8.11 (d, J = 2 Hz, 1H), 7.81 (d, J = 9.6 Hz,
3
H), 7.27–7.37 (m, 4H), 6.79 (d, J = 2.4 Hz, 1H), 6.33
1H), 7.75 (d, J = 4.8 Hz, 1H), 7.69 (s, 1H), 7.60 (s, 1H), 7.
123