Methyl 2-[2-(3,4-dimethoxyphenyl)acetyl]hydrazinecarboxyl-
ate 4Ae. Obtained from 5Ae (2.50 g, 11.89 mmol) in 70% yield
(2.22 g) as a colourless solid after crystallisation from CH2Cl2–
Et2O; mp 135–137 ЊC; νmax/cmϪ1 3310, 1748, 1724, 1696; δH 3.59
(2H, s), 3.75 (3H, s), 3.88 (3H, s), 3.89 (3H, s), 6.58 (1H, br s,
exchangeable with D2O), 6.84 (3H, m), 7.21 (1H, br s,
exchangeable with D2O); m/z 268 (Mϩ, 10%), 236 (29), 178 (38),
151 (100) (Calc. for C12H16N2O5: C, 53.73; H, 6.01; N, 10.44.
Found: C, 53.69; H, 5.88; N, 10.31%).
Methyl
2-[3-(3,4,5-trimethoxyphenyl)propanoyl]hydrazine-
carboxylate 4Bf. Obtained from 5Bf (1.21 g, 4.76 mmol) in 92%
yield (1.37 g); mp 117–119 ЊC; νmax/cmϪ1 3470, 3240, 3020, 1752,
1676; δH 2.53 (2H, t, J 7.6), 2.93 (2H, t, J 7.6), 3.75 (3H, s), 3.82
(3H, s), 3.84 (6H, s), 6.43 (2H, s), 6.8 (1H, br s), 7.48 (1H, br s)
(Calc. for C14H20N2O6: C, 53.84; H, 6.45; N, 8.97. Found: C,
53.62; H, 6.59; N, 8.78%).
Methyl
2-[3-(2-bromo-3,4,5-trimethoxyphenyl)propanoyl]-
hydrazinecarboxylate 4Bg. Compound 4Bf (200 mg, 0.64 mmol)
in CH2Cl2 (20 cm3) was treated with NBS (128 mg, 0.72 mmol)
in the same solvent (5 cm3) and the mixture stirred at rt (15 min)
after which time TFA (50 mm3, 0.65 mmol) was added. On
completion of the reaction (TLC control; CH2Cl2–5% MeOH)
the organic phase was washed with water and dried. Evapor-
ation of the solution followed by crystallisation of the residue
gave the title compound in 98% yield (245 mg); mp 99–101 ЊC
(from CH2Cl2–hexane); νmax/cmϪ1 3300, 3270, 1752, 1664;
δH 2.55 (2H, t, J 7.6), 3.05 (2H, t, J 7.6), 3.75 (3H, s), 3.84 (3H,
s), 3.86 (3H, s), 3.88 (3H, s), 6.66 (1H, s), 6.67 (1H, br s), 7.47
(1H, br s) (Calc. for C14H19BrN2O6: C, 42.98; H, 4.90; N, 7.16.
Found: C, 43.10; H, 4.60; N, 7.10%).
Methyl 2-[2-(2,5-dimethoxyphenyl)acetyl]hydrazinecarboxyl-
ate 4Af. Prepared from 5Af (1.50 g, 7.135 mmol) as a colourless
solid in 29% yield (560 mg) after crystallisation from CH2Cl2;
mp 149–150 ЊC; νmax/cmϪ1 3290, 1768, 1660; δH 3.60 (2H, s),
3.72 (3H, s), 3.76 (3H, s), 3.85 (3H, s), 6.53 (1H, br s, exchange-
able with D2O), 6.80 (1H, dd, J 8.8, J 2.8), 6.849 (1H, d, J 8.8),
6.853 (1H, d, J 2.8), 7.65 (1H, br s, exchangeable with D2O); m/z
268 (Mϩ, 32%), 236 (51), 178 (34), 151 (100) (Calc. for
C12H16N2O5: C, 53.73; H, 6.01; N, 10.44. Found: C, 53.60; H,
5.85; N, 10.25%).
Methyl
2-[2-(3-methylphenyl)acetyl]hydrazinecarboxylate
4Ag. Prepared from 5Ag (1.20 g, 7.31 mmol) as a colourless
oil, which was purified by column chromatography (CH2Cl2–
MeOH; 9 : 1) to yield a colourless solid in 76% yield (1.24 g);
mp 100–101 ЊC; νmax/cmϪ1 3260, 3200, 1724, 1670; δH 2.34 (3H,
s), 3.58 (2H, s), 3.73 (3H, s), 6.80 (1H, br s, exchangeable with
D2O), 7.09 (2H, d, J 8.0), 7.11 (1H, s), 7.23 (1H, t, J 8.0), 7.46
(1H, br s, exchangeable with D2O); m/z 222 (Mϩ, 5%), 190 (8),
132 (58), 105 (100) (Calc. for C11H14N2O3: C, 59.43; H, 6.35; N,
12.61. Found: C, 59.38; H, 6.23; N, 12.56%).
Phenyl 2-[3-(3,5-dimethoxyphenyl)propanoyl]hydrazinecarb-
oxylate 4Bh. Obtained from 5Bd (1.12 g, 4.99 mmol) in 97%
yield (1.66 g); mp 113–114 ЊC; νmax/cmϪ1 3210, 3020, 1728, 1624;
δH 2.55 (2H, t, J 7.8), 2.94 (2H, t, J 7.8), 3.74 (6H, s), 6.53 (3H,
m), 7.12 (2H, d, J 7.8), 7.21 (2H, t, J 7.8), 7.35 (2H, t, J 7.8),
7.68 (1H, br s) (Calc. for C18H20N2O5: C, 62.78; H, 5.85; N, 8.13.
Found: C, 62.84; H, 5.90; N, 7.91%).
Phenyl 2-[3-(2,5-dimethoxyphenyl)propanoyl]hydrazinecarb-
oxylate 4Bi. Obtained from 5Bi (1.12 g, 4.99 mmol) in 89% yield
(1.53 g); mp 103–104 ЊC; νmax/cmϪ1 3310, 3230, 1760, 1684;
δH (CD2Cl2) 2.52 (2H, t, J 7.7), 2.90 (2H, t, J 7.7), 3.69 (3H, s),
3.76 (3H, s), 6.74 (3H, m), 7.17 (2H, d, J 7.2), 7.21 (2H, t, J 7.2),
7.34 (2H, t, J 7.8), 7.53 (1H, br s) (Calc. for C18H20N2O5: C,
62.78; H, 5.85; N, 8.13. Found: C, 62.89; H, 5.84; N, 8.14%).
Methyl 2-(3-phenylpropanoyl)hydrazinecarboxylate 4Ba.
Obtained from 5Ba (820 mg, 4.99 mmol) in 96% yield (1.07 g)
after crystallisation (from CH2Cl2–MeOH); mp 119–120 ЊC;
νmax/cmϪ1 3300, 3250, 1735, 1668; δH 2.53 (2H, t, J 7.8), 2.98
(2H, t, J 7.8), 3.73 (3H, s), 6.99 (1H, br s), 7.24 (5H, m), 7.71
(1H, br s) (Calc. for C11H14N2O3: C, 59.45; H, 6.35; N, 12.61.
Found: C, 59.64; H, 6.39; N, 12.73%).
Methyl
2-(4-phenylbutanoyl)hydrazinecarboxylate
4Ca.
Obtained from 5Ca (2.89 g, 16.215 mmol) in 90% yield (3.43 g)
as a colourless oil, which crystallised on storage; an analytical
sample was obtained by PTLC (CH2Cl2–MeOH; 9 : 1); mp
66.5–68 ЊC; νmax/cmϪ1 3250, 1748, 1680; δH 2.00 (2H, quintet,
J 7.4), 2.22 (2H, t, J 7.4), 2.67 (2H, t, J 7.4), 3.75 (3H, s), 6.88
(1H, br s, exchangeable with D2O), 7.33–7.15 (5H, m), 7.48 (1H,
br s, exchangeable with D2O); m/z 236 (Mϩ, 6%), 204 (6), 147
(53), 91 (100) (Calc. for C12H16N2O3: C, 61.00; H, 6.83; N,
11.86. Found: C, 61.26; H, 6.69; N, 11.83%).
Methyl 2-[3-(3-methoxyphenyl)propanoyl]hydrazinecarboxyl-
ate 4Bb. Obtained from 5Bb (970 mg, 4.99 mmol) in 86% yield
(1.08 g); mp 100–103 ЊC; νmax/cmϪ1 3280, 3200, 1715, 1666;
δH 2.53 (2H, t, J 7.8), 2.95 (2H, t, J 7.8), 3.73 (3H, s), 3.78 (3H,
s), 6.77 (3H, m), 6.96 (1H, br s), 7.20 (1H, t, J 8.2), 7.65 (1H, br
s) (Calc. for C12H16N2O4: C, 57.13; H, 6.39; N, 11.10. Found: C,
56.92; H, 6.31; N, 11.03%).
Methyl 2-[3-(4-methoxyphenyl)propanoyl]hydrazinecarboxyl-
ate 4Bc. Obtained from 5Bc (970 mg, 4.99 mmol) in 97% yield
(1.22 g); mp 102–103 ЊC; νmax/cmϪ1 3220, 3020, 1728, 1664;
δH 2.50 (2H, t, J 7.8), 2.90 (2H, t, J 7.8), 3.74 (3H, s), 3.78 (3H,
s), 6.71 (1H, br s), 6.84 (2H, d, J 8.6), 7.11 (2H, d, J 8.6), 7.50
(1H, br s) (Calc. for C12H16N2O4: C, 57.13; H, 6.39; N, 11.10.
Found: C, 56.92; H, 6.31; N, 11.03%).
Methyl 2-[4-(3,4-dimethoxyphenyl)butanoyl]hydrazinecarb-
oxylate 4Cd. Prepared from 5Cd (1.69 g, 7.09 mmol) as a
colourless solid in 67% yield (1.40 g) after crystallisation from
CH2Cl2–Et2O; mp 117.5–119 ЊC; νmax/cmϪ1 3350, 3225, 1756,
1696; δH 1.98 (2H, quintet, J 7.4), 2.22 (2H, t, J 7.4), 2.62 (2H, t,
J 7.4), 3.75 (3H, s), 3.85 (3H, s), 3.87 (3H, s), 6.73–6.72 (2H, m),
6.79 (1H, d, J 8.6), 6.93 (1H, br s, exchangeable with D2O), 7.56
(1H, br s, exchangeable with D2O); m/z 296 (Mϩ, 32%), 207
(69), 164 (100) (Calc. for C14H20N2O5: C, 56.75; H, 6.80; N,
9.45. Found: C, 56.65; H, 6.92; N, 9.32%).
Methyl 2-[3-(3,5-dimethoxyphenyl)propanoyl]hydrazinecarb-
oxylate 4Bd. Obtained from 5Bd (1.12 g, 4.99 mmol) in 94%
yield (1.33 g); mp 125–127 ЊC; νmax/cmϪ1 3240, 1732, 1666;
δH 2.53 (2H, t, J 7.8), 2.92 (2H, t, J 7.8), 3.74 (3H, s), 3.77 (6H,
s), 6.33 (3H, m), 6.86 (1H, br s), 7.49 (1H, br s) (Calc. for
C13H18N2O5: C, 55.31; H, 6.43; N, 9.92. Found: C, 55.44; H,
6.51; N, 9.74%).
Methyl 2-[4-(3,4,5-trimethoxyphenyl)butanoyl]hydrazinecarb-
oxylate 4Ce. Obtained from 5Ce (1.96 g, 7.30 mmol) as a
colourless oil after column chromatography (hexane–AcOEt;
1 : 1 to 2 : 8 gradient) in 50% yield (1.20 g); νmax(film)/cmϪ1 3300,
1746, 1672; δH 2.00 (2H, quintet, J 7.4), 2.24 (2H, t, J 7.4), 2.62
(2H, t, J 7.4), 3.76 (3H, s), 3.82 (3H, s), 3.85 (6H, s), 6.42 (2H,
s), 6.85 (1H, br s, exchangeable with D2O), 7.50 (1H, br s,
exchangeable with D2O); m/z 326 (Mϩ, 67%), 294 (13), 237 (97),
194 (100) (Calc. for C15H22N2O6: M, 326.1478. Found: Mϩ,
326.1459).
Methyl 2-[3-(3,4-dimethoxyphenyl)propanoyl]hydrazinecarb-
oxylate 4Be. Obtained from 5Be (1.12 g, 4.99 mmol) in 94%
yield (1.33 g); mp 76–78 ЊC; νmax/cmϪ1 3485, 3300, 3200, 1734,
1668; δH 2.52 (2H, t, J 7.6), 2.93 (2H, t, J 7.6), 3.75 (3H, s), 3.85
(3H, s), 3.87 (3H, s), 6.77 (4H, m), 7.46 (1H, br s) (Calc. for
C13H18N2O5: M, 282.1216. Found: Mϩ, 282.1199).
J. Chem. Soc., Perkin Trans. 1, 2002, 513–528
521