Table 2 ¹ H and ¹³ C NMR assignments for syringic acid and its derivatives 2, 5 and 6 ^a

1

128.6, C

-

121.1, C

-

121.1, C

-

121.0, C

-

2

107.0, CH

7.31 (s)

106.8, CH

7.36 (s)

106.9, CH

7.35 (s)

106.8, CH

7.38 (s)

3

148.0, C

-

146.7,C

-

146.7, C

-

146.6, C

-

4

142.6, C

-

139.4, C

-

139.4, C

-

139.4, C

-

5

148.0, C

-

146.7, C

-

146.7, C

-

146.6, C

-

6

107.0, CH

7.31 (s)

106.8, CH

7.36 (s)

106.9, CH

7.35 (s)

106.8, CH

7.38 (s)

1'

-

-

136.3, C

-

137.9, C

-

136.5, C

-

2'

-

-

128.2, CH

7.45 (dd, 7.8, 1.2)

113.8^d, CH

6.98 (d, 2.2)

105.9, CH

6.59 (d, 2.4)

3'

-

-

128.6, CH

7.39 (dd, 7.8, 7.2)

160.0, C

-

160.9, C

-

4'

-

-

128.2, CH

7.34 (dd, 7.2, 1.2)

113.7^d, CH

6.88 (dd, 8.1, 2.2)

100.0, CH

6.45 (dd, 2.4, 2.4)

5'

-

-

128.6, CH

7.39 (dd, 7.8, 7.2)

129.8, CH

7.30 (dd, 10.0, 8.8)

160.9, C

-

6'

-

-

128.2, CH

7.45 (dd, 8.8, 1.2)

120.4, CH

7.02 (d, 7.7)

105.9, CH

6.59 (d, 2.4)

7'-CH₂

-

-

66.7, CH₂

5.36 (s)

66.8, CH₂

5.32 (s)

66.5, CH₂

5.30 (s)

3,5-OCH₃

56.1, CH₃

3.86 (s)

56.5, CH₃

3.93 (s)

56.6, CH₃

3.93 (s)

56.5, CH₃

3.95 (s)

3'-OCH₃

-

-

-

-

55.3, CH₃

3.82 (s)

55.4, CH₃

3.82 (s)

5'-OCH₃

-

-

-

-

-

-

55.4, CH₃

3.82 (s)

OH

-

4.93 (s)

-

5.92 (s)

-

5.91 (br s)

-

5.95 (s)