Structure and Fungicidal Activity in a Series of 2'-Formyldiphenyl-2-carboxylic Acid Esters
Abstract Generated abstract
A series of alkyl esters of 2′-formyldiphenyl-2-carboxylic acid was synthesized by esterifying the parent acid with the corresponding alcohols and evaluated for fungicidal activity. Tests at a 0.05 active-principle concentration against Botrytis cinerea, Fusicladium dendriticum, and Fusarium oxysporum showed that activity generally increased with the molecular weight of the alcohol radical up to a limit, then declined. The esters were more active than the free acid in these assays, suggesting that esterification can enhance, rather than necessarily reduce, fungicidal properties depending on both the substituent and the acid structure.
Full Text
Structure and Fungicidal Activity in a Series of Esters of 2′-Formyldiphenyl-2-carboxylic Acid
I. L. Khalfina
(Presented by the scientific-methodological seminar of the Chemical-Technological Faculty)
According to fragmentary information available in the literature, esters of carboxylic acids possess high effectiveness against agricultural pests and diseases \([1—3]\).
On the basis of these data we synthesized and tested a series of complex alkyl esters of 2′-formyldiphenyl-2-carboxylic acid.
The esters of 2′-formyldiphenyl-2-carboxylic acid were obtained by us by the usual esterification reaction of the acid with the corresponding alcohols.
Table of results of testing the preparations as fungicides
Compounds of the general formula
\[ \text{2′-CHO-diphenyl-2-COOR} \]
| N | R | Concentration of preparation by active principle | botrytis cinerio | fusidadium dendriticum | fusarium oxysporum |
|---|---|---|---|---|---|
| 1 | H | 0,05 | 82,8 | 53,5 | 26,3 |
| 2 | CH\(_3\) | 0,05 | 88,8 | 46,7 | 88,4 |
| 3 | C\(_2\)H\(_5\) | 0,05 | 84,1 | 75,3 | 91,9 |
| 4 | n—C\(_3\)H\(_7\) | 0,05 | 100 | 75,3 | 88,6 |
| 5 | iso—C\(_3\)H\(_7\) | 0,05 | 100 | 66,6 | 100 |
| 6 | n—C\(_4\)H\(_9\) | 0,05 | 84,3 | 64,2 | 73,6 |
| 7 | iso—C\(_4\)H\(_8\) | 0,05 | 81,2 | 57,1 | 63,1 |
On the basis of the data presented in the table, the following relationships between the strength of the fungicidal action and the structure of the compound may be derived:
- Fungicidal activity increases with an increase in the molecular weight of the alcohol radical; however, the increase in fungicidal activ-
for the esters of 2′-formyldiphenyl-2-carboxylic acid occurs up to a certain limit, after which it decreases.
This phenomenon has repeatedly been observed by various investigators in studies of the bactericidal and insecticidal activity of various organic compounds [4].
- The esters of 2′-formyldiphenyl-2-carboxylic acid are more active than the acid itself; consequently, esterification in this case leads to an enhancement of fungicidal properties.
This conclusion is not consistent with the data available in the literature indicating that substitution of the hydroxyl group of the carboxyl lowers the fungicidal properties of compounds. The results obtained by us indicate that not every substitution of the hydroxyl group of the acid carboxyl lowers fungicidal properties. A major role is probably played both by the nature of the substituent and by that of the acid itself.
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