Tricyclic Compounds as Insect Repellents
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Solution Overview
Problem
Current insect repellents are developing resistance and have side effects, necessitating the development of novel repellents to control the spread of tropical diseases.
Innovation Solution
The synthesis of tricyclic compounds of formula (I) or their salts, which are used as insect repellents, involves specific steps including the use of boron trifluoride diethyl etherate, Grubbs second-generation catalyst, manganese triacetate dehydrate, and tert-butyl hydroperoxide, to produce compounds effective against mosquito bites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing insect repellents (DEET, nootkatone) are used, then repellent activity is achieved, but resistance develops and side effects occur
Solution Approach 1:
The patent modifies the chemical structure of known repellents by changing molecular parameters - specifically creating tricyclic compounds with modified ring systems and functional groups. The compounds have different molecular weights, functional group arrangements, and stereochemical configurations compared to DEET and nootkatone, thereby maintaining repellent efficacy while avoiding resistance and side effects
Solution Approach 2:
The patent creates composite molecular structures combining different functional groups and ring systems in a single tricyclic framework. These compounds integrate multiple structural motifs that work synergistically to provide repellent activity, exemplified by compounds like (1aR,1bR,2R,6aS)-1,1,1b,2-Tetramethyl-1,1a,1b,2,3,6a-hexahydrocyclopropa[a]indene-4,6-dione which combines carbonyl groups with cyclopropa[a]indene core structure
2Reliability
If natural repellents like nootkatone are used, then repellent activity is achieved, but the compounds are difficult to synthesize and purify
Solution Approach 1:
The patent divides the synthesis process into discrete, manageable steps starting from commercially available starting materials. The multi-step synthesis includes: (1) formation of enone compounds, (2) cyclopropanation to form tricyclic core, (3) oxidation to carbonyl groups, and (4) purification by crystallization. Each step is optimized for yield and purity, making the overall process feasible for industrial production
Solution Approach 2:
The patent employs specific reagents and intermediaries that facilitate clean transformations and easy purification. For example, using specific oxidizing agents to form carbonyl groups, employing crystallization as an intermediary purification step, and using protective groups during synthesis that can be easily removed. These intermediaries enable the transformation of simple starting materials into complex tricyclic compounds with high purity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The tricyclic compounds provide protection against mosquito bites for 1.23 to 6.46 hours at concentrations of 0.25 to 0.50 mg/cm², offering improved efficacy compared to existing repellents.
Implementation Method 1
adding boron trifluoride diethyl etherate (BF3.OEt2) to a solution of diene compounds of formula 4 and (E)-2-methylbut-2-enal of formula 3 in Dichloromethane (CH2Cl2) followed by stirring the reaction for the period ranging from 10 to 12 h at temperature in the range of −78° C. to 30° C. to afford compound of formula 6
Implementation Method 2
adding Grubbs second-generation catalyst to a solution of compound of formula 6 of step (a) followed by stirring the mixture for 22 to 24 h temperature in the range of 25 to 30° C. to afford compound of formula 7
Implementation Method 3
adding Manganese triacetate dehydrate [Mn(OAC)3.2H2O] and tert-butyl hydroperoxide (t−BuOOH) to a solution of compound of formula 7 of step (b) in ethyl acetate (EtOAc) followed by stirring the reaction mixture for 22 to 24 h at temperature 25 to 30° C. to give compound of formula 8a
Data Source
AI summary
The present invention discloses tricyclic compounds of formula (I) or salt thereof and their process for synthesis. Further, the present invention relates to the use of these novel tricyclic compounds of formula (I) or salt thereof as insect repellents.