Description:FIELD OF THE INVENTION
The present invention relates to method of synthesizing cashew phenolic lipids. More particularly, the present invention discloses method for the synthesis of anacardic acid which is rapid and scalable. Said cashew phenolic lipids possesses anti-diabetic activities.

BACKGROUND OF THE INVENTION
Cashew nut shell liquid (CNSL), a byproduct of the cashew industry, is a rich source of phenolic lipids. These compounds have attracted significant interest due to their potential applications in various fields, such as medicine, materials science, and agriculture.

Anacardic acid, cardol, and cardanol are phenolic compounds derived from the cashew tree (Anacardium occidentale), specifically from the cashew nutshell liquid (CNSL). These compounds possess unique chemical structures and properties that make them valuable in various industrial and medicinal applications.

Anacardic acid is a complex phenolic lipid characterized by a long hydrocarbon chain with a carboxylic acid functional group. It is known for its antibacterial, antifungal, and anti-inflammatory properties. Anacardic acid can be found in the shell of cashew nuts and is responsible for the irritating effects often associated with raw cashew shells. It is majorly used as an antimicrobial agent, in various pharmaceutical preparations, and Industrial applications.

However, the extraction and synthesis of cashew phenolic lipids acid from natural sources have been associated with several challenges.

Reference is made to patent application no. WO2022106988-A1 titled as “method for obtaining a mixture of derivatives of at least two compounds chosen from the cardol, cardanol and anacardic acids”. The prior art relates to a method for obtaining a mixture of oxycarboxylate and/or oxycarboxylic acid derivatives of at least two compounds chosen from the cardols, cardanols and anacardic acids. Characteristically, said one or more families of four compounds are added to a salt of a halogenated carboxylate derivative and/or to a halogenated carboxylic ester in a solution containing a strong base and an alcohol and the resulting reaction mixture is heated to a temperature greater than or equal to 50°C and less than or equal to 90°C and in particular equal to 70°C, for a given period.

Another reference was made to a non-patented document titled as “potential biological applications of bio-based anacardic acids and their derivatives” by Fatma B. Hamad 1 and Egid B. Mubofu. The paper discloses how a cashew nut shells (CNS), which are agro wastes from cashew nut processing factories, have proven to be among the most versatile bio-based renewable materials in the search for functional materials and chemicals from renewable resources. CNS are produced in the cashew nut processing process as waste, but they contain cashew nut shell liquid (CNSL) up to about 30–35 wt. % of the nut shell weight depending on the method of extraction. CNSL is a mixture of anacardic acid, cardanol, cardol, and methyl cardol, and the structures of these phenols offer opportunities for the development of diverse products. For anacardic acid, the combination of phenolic, carboxylic, and a 15-carbon alkyl side chain functional group makes it attractive in biological applications or as a synthon for thesynthesis of a multitude of bioactive compounds.

Accordingly, prior research has focused on extracting and purifying these compounds directly from CNSL. However, this approach has limitations, including low yields, complex purification processes, and potential environmental concerns. Additionally, the composition of CNSL can vary depending on factors such as geographical origin and processing conditions, making it difficult to obtain consistent and high-quality products

Therefore, to overcome these challenges, a novel synthetic approach is required. This invention aims to provide a more efficient and controlled method for synthesizing cashew phenolic lipids, enabling the production of high-purity compounds with consistent quality. The use of Suzuki-Miyaura coupling, a powerful tool in organic synthesis, allows for the modular assembly of complex molecules, including those found in CNSL.
By developing efficient synthetic routes, this invention contributes to the sustainable utilization of cashew nut shells, reducing waste and promoting the development of value-added products from this renewable resource.

OBJECT OF THE INVENTION
In order to overcome the shortcomings in the existing state of the art, the present invention provides novel methods for synthesizing phenolic lipids, using different synthetic methodologies.

Yet another objective of the invention is to provide different methods for synthesizing phenolic lipids with varying yields.

Yet another objective of the invention is to provide novel methods for synthesizing phenolic lipids, a biologically active compound using different synthetic methods.

Yet another objective of the invention is to provide methods that are efficient, and scalable to multi-gram levels.

Another objective of the present invention is to provide a method for synthesizing phenolic lipids which devoid of the use of hazardous pyrophoric reagents for deprotection, making the synthetic process safer and more environmentally friendly.

Yet another objective of the present invention is to provide a method of synthesizing phenolic lipids which is optimized by reducing the steps of synthesis and requires minimum purification efforts, hence reducing the cost of overall synthesis.

SUMMARY OF THE INVENTION:
The present invention provides innovative methods for synthesizing cashew phenolic lipids with high yields and efficiency, thereby advancing the potential therapeutic applications of these compounds in metabolic and viral disease treatments.

More particularly, the present invention discloses novel methods for synthesizing anacardic acid which is rapid and scalable.

The method involves using a chemical reaction called Suzuki-Miyaura Coupling (SMC) to create important natural compounds like anacardic acid, cardol, and cardanol. The process starts with a simple starting material and involves several steps. First, the starting material is modified to make it more reactive. Then, the SMC reaction is used to join different parts of the molecule together. Finally, the resulting compound is further modified to obtain the desired natural product. This method is efficient and produces these compounds in good yields, making it a valuable tool for chemists.

A one-pot deprotection and hydrolysis step yields anacardic acid with an overall yield of 55-61%.

Hence, SMC reaction is successful in making natural products such as anacardic acid with good overall yield.

BRIEF DESCRIPTION OF DRAWINGS
Scheme 1 depicts synthesis of anacardic acid

DETAILED DESCRIPTION OF THE INVENTION WITH ILLUSTRATIONS AND EXAMPLES
While the invention has been disclosed with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.

Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise. The meaning of “a”, “an”, and “the” include plural references. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein.

This invention presents innovative methods for synthesizing cashew phenolic lipids, a compound with potential applications in treating metabolic and viral diseases. The whole route is novel and a shortened path for synthesizing cashew phenolic lipids such as anacardic acid as shown in Scheme 1 which is constituents of the Anacardium occidentale plant has been synthesized very efficiently.

Scheme 1: Synthesis of Anacardic acid.

Anacardic acid
The starting material 1 is converted into their methylated derivative (2) using CH3I in the presence of K2CO3, indicated in scheme 1. Then, the SMC (Suzuki-Miyaura Coupling)-key reaction is performed under optimized conditions, where the coupled product is obtained with a maximum yield of 80-85%. Subsequently, the product, anacardic acid is obtained by the deprotection via BBr3 (to remove methyl group) followed by hydrolysis of the ester in one pot. The overall yield from the starting material to anacardic acid is about 55-61%.

Hence, SMC reaction is successful in making natural products such as anacardic acid with good overall yield.

Accordingly, the present invention offers a streamlined and effective route to produce valuable cashew phenolic lipids. The improved yields and reduced reaction steps make this method economically attractive and environmentally friendly. By enabling the large-scale production of these compounds, this invention has the potential to accelerate research into their therapeutic applications and contribute to the development of new treatments for metabolic and viral diseases.
, Claims:We claim:
1. A method of synthesizing anacardic acid, wherein said method comprising the steps of:
a) methylating a halogenated aromatic compound to form a methylated intermediate;
b) subjecting the methylated intermediate to a Suzuki-Miyaura coupling reaction with an aryl halide in the presence of a palladium catalyst and a base to form a coupled product; and
c) deprotecting and hydrolyzing the coupled product to obtain anacardic acid.
2. The method as claimed in claim 1, wherein the halogenated aromatic compound is selected from the group consisting of chloro-, bromo-, and iodo-aromatic compounds.
3. The method as claimed in claim 1, wherein the aryl halide is selected from the group consisting of aryl chlorides, aryl bromides, and aryl iodides.
4. The method as claimed in claim 1, wherein the palladium catalyst is selected from the group consisting of palladium(0) and palladium(II) catalysts.
5. The method as claimed in claim 1, wherein the base is selected from the group consisting of potassium carbonate, sodium carbonate, and triethylamine.