135158-54-2

Acibenzolar-S-methyl (Novartis) has attracted special attention because it acts against a very wide range of plant diseases but does not directly affect the growth or metabolism of the causal organisms. It is known to act by stimulating systemic activated resistance (SAR) in the treated plant. The well-established compound probenazole, which for some years has been the leading treatment for rice blast in Japan, is thought to act in a similar way. Pathogen resistance to probenazole has not developed, and such stability of performance may well be a general feature of SAR-inducing compounds.

The pure product is a white to beige powdery solid with a pseudo-burnt odor. Its mp value is 132.9°C, bp is approximately 267°C, relative density is 1.54 (20°C), and vapor pressure is 4.4×10-4 Pa (25°C). Solubility at 25°C is: methanol 4.2 g/L, ethyl acetate 25 g/L, n-hexane 1.3 g/L, toluene 36 g/L, acetone 28 g/L, n-octanol 5.4 g/L, dichloromethane 160 g/L, and water 7.7 g/L. Partition coefficient is 3.1 (20°C). Hydrolysis half-life is 3.8 years (20°C, pH=5), 23 weeks (20°C, pH=7), and 19.4 hours (20°C, pH=9).

CGA245704 is used to control a range of diseases in wheat and it is being developed for use on rice, bananas, vegetables and tobacco.

Plant disease resistance activator.

ChEBI: A benzothiadiazole that is the S-methyl thioester derivative of acibenzolar. It is used as a fungicide and plant activator on a variety of crops, including cotton, chili peppers, lettuce, onions, spinach, tobacco, and tomatoes.

Acibenzolar-S-methyl is manufactured through a multi-step chemical synthesis that begins with the formation of the 1,2,3-benzothiadiazole core. This heterocyclic ring is created via a classic ring-closure reaction, where a thiol group reacts with an adjacent diazonium group on a benzene ring. The resulting compound, 1,2,3-benzothiadiazole-7-carboxylic acid, is then converted into its S-methyl thioester form through standard chemical transformations, typically involving hydrolysis to the free acid followed by reaction with thionyl chloride to form the acid chloride, and finally methylation with a thiol reagent.

Systemic Activated Resistance (SAR). Induces host plant defence.

Very little information on the fate of CGA245704 has been published. It is readily degraded in soil and plants and it is rapidly eliminated from animals. A partial metabolic pathway is shown in Scheme 1.

Store at -20°C

CGA245704 is a stable substance and it is very stable in solution other than at high pH values. Its DT₅₀ values (20 °C) at pH 5, 7 and 9 were 3.8 years, 23 weeks and 19 hours, respectively (PM). Hydrolysis of the thioester link and ring opening would be anticipated.

Fungicide