3172
R. Murali et al. / Tetrahedron 57 *2001) 3165±3174
crystallize. The product was ®ltered and washed with ben-
zene -5 ml) to yield 90% of analytically pure cycloadduct
cyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid /6f). Yield
1
57%; mp: 154±1558C; H NMR: d 8.20-d, J8.6 Hz,
1
6a, mp: 147±1488C; H NMR: d 7.36±7.22 -m, 5H), 6.55
2H), 7.43 -d, J8.6 Hz, 2H), 6.57 -dd, J5.7,1.7 Hz, 1H),
6.44 -d, J5.7 Hz, 1H), 5.19 -d, J1.7 Hz, 1H), 4.73 -d,
J15.7 Hz, 1H), 4.53 -d, J15.7 Hz, 1H), 3.80-d, J
11.6 Hz, 1H), 3.61 -d, J11.6 Hz, 1H), 2.38 -s, 1H), 1.25
-s, 3H); 13C NMR: 175.68, 174.49, 147.58, 143.35, 137.73,
133.11, 128.56, 124.15, 90.99, 81.52, 56.66, 53.33, 47.24,
46.09, 21.64 ppm; elemental analysis calcd for C17H16N2O6:
C, 59.30; H, 4.68; N, 8.14. Found: C, 58.89; H, 4.63; N,
8.04.
-dd, J5.7, 1.6 Hz, 1H), 6.38 -d, J5.7 Hz, 1H), 5.22 -d,
J1.5 Hz, 1H), 4.73 -d, J14.9 Hz, 1H), 4.33 -d, J
14.9 Hz, 1H), 3.65-AB q, J11.9 Hz, 2H), 2.39 -s, 1H),
1.23 -s, 3H); 13C NMR: 175.6, 174.1, 137.7, 135.7, 133.1,
128.9, 128.0, 127.8, 91.0, 81.7, 56.4, 53.7, 47.0, 46.8,
21.8 ppm; elemental analysis calcd for C17H17NO4: C,
68.22; H, 5.72; N, 4.68. Found: C, 68.32; H, 5.69; N, 4.74.
6.4.2.
5-Methyl-3-/2-methylbenzyl)-4-oxo-10-oxa-3-
azatricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid /6b).
6.4.7. 3-/2-Naphthylmethyl)-5-methyl-4-oxo-10-oxa-3-
azatricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid /6g).
1
Yield70%; mp: 164±1658C; H NMR: d 7.22±7.17 -m,
1
4H), 6.56 -dd, J5.7, 1.7 Hz, 1H), 6.38 -d, J5.7 Hz, 1H),
5.24 -d, J1.7 Hz, 1H), 4.65 -d, J14.8 Hz, 1H), 4.47 -d,
J14.8 Hz, 1H), 3.63 -d, J12.1 Hz, 1H), 3.53 -d, J
12.1 Hz, 1H), 2.40-s, 1H), 2.29 -s, 3H), 1.23 -s, 3H); 13C
NMR: 175.09, 174.17, 137.69, 137.04, 133.30, 133.06,
130.73, 129.16, 128.07, 126.23, 90.98, 81.71, 56.47,
53.75, 46.87, 45.13, 21.91, 19.02 ppm.; elemental analysis
calcd for C18H19NO4: C, 68.99; H, 6.11; N, 4.47. Found: C,
69.00; H, 5.98; N, 4.54.
Yield83%; mp168±1698C; H NMR: d 7.85±7.80-m,
3H), 7.70-s, 1H), 7.5±07.47 -m, 2H), 7.34 -dd,
J
8.4,1.7 Hz, 1H), 6.56 -dd, J5.7, 1.7 Hz, 1H), 6.36 -d, J
5.7 Hz, 1H), 5.26 -d, J1.7 Hz, 1H), 4.91 -d, J14.7 Hz,
1H), 4.47 -d, J14.7 Hz, 1H), 3.71 -d, J11.9 Hz, 1H), 3.63
-d, J11.9 Hz, 1H), 2.42 -s, 1H), 1.24 -s, 3H); 13C NMR:
176.20, 173.06, 137.97, 133.40, 132.98, 132.82, 129.09,
127.88, 127.81, 127.39,. 127.22, 126.51, 126.28, 125.77,
91.34, 82.24, 77.30, 55.91, 54.44, 47.21, 22.09 ppm;
elemental analysis calcd for C21H19NO4: C, 72.19; H,
5.48; N, 4.01. Found: C, 72.15; H, 5.29; N, 4.11.
6.4.3. 3-/2-Hydroxybenzyl)-5-methyl-4-oxo-10-oxa-3-aza-
acid
tricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic
/6c).
1
Yield83%; mp: 163±1648C; H NMR: d -acetone-D6):
7.23±7.11 -m, 2H), 6.85±6.77 -m, 2H), 6.58 -s, 2H), 5.01
-s, 1H), 4.55 -d, J15.0Hz, 1H), 4.33 -d, J15.0Hz, 1H),
4.00 -d, J11.9 Hz, 1H), 3.68 -d, J11.9 Hz, 1H), 2.26 -s,
1H), 1.13 -s, 3H) ppm;13C NMR -CD3OD): 177.15, 175.99,
156.84, 138.49, 134.73, 130.76, 129.98, 123.28, 120.75,
116.30, 92.28, 82.82, 58.40, 54.12, 50±45 shielded, 42.72,
21.85; elemental analysis calcd for C17H17NO5: C, 64.75; H,
5.43; N, 4.44. Found: C, 64.54; H, 5.45; N, 4.45
6.4.8. 3-Cyclohexyl-5-methyl-4-oxo-10-oxa-3-azatricyclo-
[5.2.1.01,5]dec-8-ene-6-carboxylic acid /6h). Yield76%;
1
mp: 165±1678C; H NMR: d 6.67 -dd, J5.7,1.7 Hz, 1H),
6.42 -d, J5.7 Hz, 1H), 5.29 -s, 1H), 3.92 -m, 1H), 3.78 -d,
J12.0Hz, 1H), 3.72 -d, J12.0Hz, 1H), 2.41 -s, 1H),
1.80±1.66 -m, 5H), 1.44±1.29 -m, 5H), 1.20 -s, 3H); 13C
NMR: 175.17, 173.49, 137.62, 132.89, 91.0, 81.79, 56.23,
53.92, 50.84, 43.36, 29.99, 29.60, 25.23, 25.07, 21.89 ppm;
elemental analysis calcd for C16H219NO4: C, 65.96; H, 7.26;
N, 4.81. Found: C, 65.91; H, 7.32; N, 4.87.
6.4.4. 3-/2-Methoxybenzyl)-5-methyl-4-oxo-10-oxa-3-aza-
acid
tricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic
/6d).
6.4.9. 3-Benzyl-6-methyl-9-/methylsulfanyl)-4-oxo-10-
oxa-3-azatricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid
1
Yield66%; mp: 159±1608C; H NMR: d 7.32±7.19 -m,
2H), 6.96±6.87 -m, 2H), 6.60-dd, J5.7,1.8 Hz, 1H), 6.36
-d, J5.7 Hz, 1H), 5.33 -d, J1.7 Hz, 1H), 4.70-d, J
14.6 Hz, 1H), 4.45 -d, J14.6 Hz, 1H), 3.82 -s, 3H), 3.70
-d, J12.2 Hz, 1H), 3.62 -d, J12.2 Hz, 1H), 2.44 -s,
1
/9a). Yield80%; mp: 178±1808C; H NMR: d 7.37±7.21
-m, 5H) 5.85 -d, J2.0Hz, 1H), 5.28 -d, J2.0Hz, 1H),
4.59 -d, J14.9 Hz,1 H), 4.49 -d, J14.9 Hz, 1H), 3.71 -d,
J12.1 Hz, 1H), 3.50-d, J12.1, 1H), 2.48 -s, 1H), 2.33 -s,
3H), 1.33 -s, 3H); 13C NMR: 174.88,172.45, 146.47, 135.19,
129.21, 128.26, 128.21, 122.05, 91.29, 86.47, 58.55, 55.96,
47.29, 24.05, 15.61 ppm; elemental analysis calcd for
C18H19NO4S: C, 62.59; H, 5.54; N, 4.05; S, 9.28. Found:
C, 62.23; H, 5.51; N, 4.11; S, 9.03.
1H),1.20-s, 3H);
13C NMR: 175.84,173.41, 157.62,
137.83, 132.91, 130.06, 121.29, 123.45, 120.86, 110.40,
91.26, 82.12, 55.82, 55.34, 54.33, 47.32, 42.05, 21.95
ppm; elemental analysis calcd for C18H19NO5: C, 65.64;
H, 5.81; N, 4.25. Found: C, 65.87; H, 5.71; N, 4.36.
6.4.5. 3-/4-Methoxybenzyl)-5-methyl-4-oxo-10-oxa-3-aza-
acid
6.4.10. 3-Benzyl-5-methyl-8-/methylsulfanyl)-4-oxo-10-
oxa-3-azatricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid
/10b). Yield92%; mp:178±1798C; 1H NMR: d 7.35±
7.21 -m, 5H), 5.79 -s, 1H), 5.03 -s, 1H), 4.73 -d, J
14.9 Hz, 1H), 4.29 -d, J14.9 Hz, 1H), 3.62 -d, J
11.9 Hz, 1H), 3.55 -d, J11.9 Hz, 1H), 2.44 -s, 1H), 2.29
-s, 3H), 1.21 -s, 3H); 13C NMR: 175.53, 173.75, 149.53,
135.68, 128.03, 127.84, 119,72, 92.48, 83.89, 58.69,
54.17, 47.02, 46.87, 21.92, 15.43 ppm; elemental analysis
calcd. for C18H19NO4S: C, 62.59; H, 5.54; N, 4.05; S, 9.28.
Found: C, 62.21; H, 5.57; N, 4.09; S, 9.01.
tricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic
/6e).
1
Yield72%; mp: 1458C; H NMR: d 7.32±7.19 -m, 2H),
6.96±6.87 -m, 2H), 6.60-dd, J5.7,1.7 Hz, 1H), 6.36 -d,
J5.7 Hz, 1H), 5.33 -d, J1.7 Hz, 1H), 4.70-d, J14.6 Hz,
1H), 4.45 -d, J14.6 Hz, 1H), 3.82 -s, 3H), 3.70-d, J
12.2 Hz, 1H), 3.62 -d, J12.2 Hz, 1H), 2.44 -s, 1H), 1.20
-s, 3H); 13C NMR: 175.71, 173.72, 159.28, 137.83, 132.97,
129.62, 129.42, 114.33, 91.11, 81.96, 56.23, 55.34, 53.99,
46.91, 46.34, 21.88 ppm; elemental analysis calcd. for
C18H19NO5: C, 65.64; H, 5.81; N, 4.25. Found: C, 65.58;
H, 5.85; N, 4.23.
6.4.11. 3-Benzyl-5,9-dimethyl-4-oxo-10-oxa-3-azatricyclo-
6.4.6. 3-/4-Nitrobenzyl)-5-methyl-4-oxo-10-oxa-3-azatri-
[5.2.1.01,5]dec-8-ene-6-carboxylic acid /10c). Yield82%;