Description:Technical Field of the Invention
The invention relates to a method for synthesizing sex pheromone of peach moth in particular, an improved synthesis of E-5-decenyl acetate, the major component of the Peach Twig Borer (PTB) & peach-strip/steak wheat moth.

Background of the Invention
The peach-stripe wheat moth & Peach Twig Borer (PTB) for Anarsia linetella is distributed in east and middle parts of Asia, middle and south parts of Europe, North America, and the like. Mainly harms various fruit trees such as peaches, apricots, apples, pears, persimmons, narrow-leaved oleaster, plums and the like. The Peach Twig Borer (PTB) is a major pest in stone fruit orchards. Insecticides are applied directly to the fruit, a practice that is contrary to an increasing preference for organic produce as well as contrary to water quality issues and other environmental concerns. Finally, the PTB is becoming resistant to many of the common insecticides.

An alternative method to control insect populations involves the use of the insect's sex attractant to confuse the male insect and thereby prevent mating and eliminate future insect generations. This technique is called mating pattern disruption. The sex pheromone of the peach fruit moth has the advantages of high biological activity, low using amount, no harm to natural enemies and the like, and has an important function in green prevention and control of the peach fruit moth.

The biggest problem in using mating pattern disruption to control insect populations is the cost of producing the insect pheromone. Generally the cost of insect pheromone production and application is much higher than traditional insecticide applications. Methods that reduce the production costs of insect pheromones would make mating pattern disruption an economical technique for controlling insect populations.

Peach twig borer is one of the most serious pests, whose sex pheromone is 5E-decen-1-ol and 5E-decenyl acetate. Chinese journal of organic chemistry by Huang, Fei et al, 2017 discloses Simple synthesis of 5E-decen-1-ol and 5E-deceyl acetate, the sex pheromone of peach twig borer from acrolein, by addition reaction of acetylene followed by Grignard reaction, hydrolysis and reduction to give 5E-decen-1-ol, finally esterification of the alcohol to afford 5E-decenyl acetate.

WO2007053926A1 discloses a composition and procedure for manipulating behavior of the peach twig borer, Anarsia lineatella (Zeller) (Lepidoptera: Gelechiidae). In particular, this invention relates to using specific semiochemical and sonic signals for modifying the behavior of the peach twig borer. The invention also relates to a composition of pheromonal and sonic signals for manipulating the behavior of male A. lineatella, said composition comprising pheromone components (E)-5-decenyl acetate (E5-10:OAc) and (E)-5-decenol (E5-10:OH).

PTB pheromone is common blend ratio of 85:15 of (E)-5-decenyl acetate and (E)-5-decenol. Thus production of 5-decenyl acetate, which is the major component of PTB pheromone, is a significant step of the PTB pheromone manufacturing process. The acetate can be subsequently removed by hydrolysis to obtain E-5-decenol, the other component of PTB pheromone.

The sex pheromone of the peach strips and wheat moths is firstly separated by Carde and the like, and is identified to be (E) -5-decen-1-alcohol acetate as a main component and (E) -5-decen-1-alcohol as a secondary component as referred by Roelofs, W.; Kochansky, J.; Anthon, E.; Rice, R.; Carde, R.environ.Entomol.1975,4, 580-Bull., discloses the sex pheromone of the peach strips and wheat moths is difficult to extract, and the application research of the sex pheromone of the peach strips and wheat moths in pest control is seriously hindered.

Although the synthesis research of sex pheromone of the peach-streak wheat moth & Peach twig borer is achieves certain results, the problems of harsh reaction conditions, long reaction route, high reagent toxicity and high costing and the like still exist.

Therefore, there is a need to develop a novel method for synthesizing the sex pheromone of the peach-strip wheat moth & Peach twig borer that has fast & mild reaction conditions with good environmental compatibility that have economic significance with high yields.

Brief Summary of the Invention
An object of the invention is to provide an improved synthesis of PTB pheromone (E)5-Decenyl acetate.

Another object of the invention is to aim at a kind of raw material of offer is cheap and easy to obtain, simple synthetic route & reaction conditions. The sex pheromone (E)5-Decenyl acetate of Anarsia lineatella which is synthesized is economic with high purity & stereoselectivity.

Detailed Description of the invention

Main object of the present invention to provide a novel synthetic route of a sex attractant the PTB pheromone, namely (E)5-Decenyl acetate using n-hexanal and Malonic acid wherein the process comprises the following steps

The invention aims to provide a novel method for synthesizing sex pheromone of peach moths particularly peach strips and wheat moths (Peach Twig Borer (PTB) & peach-strip wheat moth).

Another object of the present invention provides a kind of synthetic method of namely (E)5-Decenyl acetate, comprise the steps：

a. condensation of n-hexanal and Malonic acid in presence of base triethyl amine or DMF (N,N di-methyl formamide) to generate 3E-Octenoic acid, more preferably triethylamine;
b. then reducing 3E-Octenoic acid in presence of Vitride or sodiumborohydride or Lithium aluminium hydride to obtain 3E-octen-1-ol, more preferably vitride;
c. followed by chlorination of 3E-octen-1-ol using Thionyl chloride, or PCl3/POCl3, to more preferably thionyl chloride, to obtain 1-chloro-3E-octene;
d. then carrying out -coupling of 1-chloro-3E-octene and ethylene oxide with Grignard reagents to obtain 5E-decenol; and
e. finally carrying out acetylation of 5E-decenol using acetyl chloride or acetic anhydride to obtain (E) -5-deceny1 acetate.

The resultant sex pheromone E-5-decenyl acetate is utilized for manipulating behavior of male peach twig borer of Anarsia lineatella (Zeller) (Lepidoptera: Gelechiidae).

Another embodiment of the present invention to provide the method for synthesizing the sex pheromone of the peach strip wheat moth comprises the following steps.

1. Synthesis of 3E-Octenoic acid (5):
Condensation of n-Hexanal & Malonic acid under nitrogen atmosphere at room temperature, in presence of base Triethyl amine at high temperature of about 80°C, continued the stirring of mixture then cooled, separated organic and aqueous layer by addition of HCl & MTBE, obtain 3E-Octenoic acid.

2. Synthesis of 3E-octen-1-ol (4):
Reduction of 3E-Octenoic acid using a reducing agent Vitride or Sodiumborohydride or Lithium aluminium hydride to obtain 3E-octen-1-ol , most preferably Vitride is used.

3. Synthesis of 1-Chloro-3E-Octene (3):
Simple chlorination of 3E octane-1-ol using chlorinating reagents Thionyl chloride or PCl3 or POCl3 or PCl5, in the presence of base media triethylamine, under reflux temperatures to obtain 1-Chloro-3E-Octene, most preferably thionyl chloride is used.

4. Synthesis of 5E-decenol (2):
Grignard coupling reaction is carried out using magnesium turnings & Iodine to 1-chloro-3E-octene under nitrogen atmosphere, at reflux temperatures to obtain 5E-decenol. These coupling reactions are carried out to extend carbon chain without disturbing the position of E-type double bond, that have the advantages of simple synthetic route, mild reaction condition, good environmental compatibility and the like.

5. Synthesis of 5E-Decenyl acetate (1):
Simple acetylation reaction of 5E-Decenol is carried out using acetylating reagent like acetyl chloride or acetic anhydride, more preferably acetyl chloride is used to obtain 5E-Decenyl acetate.

The present synthesis route of sex pheromone of peach moth particularly Peach Twig Borer (PTB) & peach-strip wheat moth is resulted with mild reaction conditions, simple reaction route, and low reagent toxicity and good environmental compatibility, has important theoretical significance and application value.

Scheme 1: Illustrates the synthesis of 5E-decenyl acetate

Characterization of 5E-decenyl acetate:

1H NMR (CDCl3, 400 MHz, δ ppm): 5.43-5.33 (m, 2H), 4.02 (t, 2H), 2.08 (s, 3H), 1.98 (m, 4H), 1.64 (m, 2H), 1.4 (m, 2H), 1.3 (m, 4H), 0.88 (t, 3H).

Experimental details:
Example 1. Synthesis of 3E-Octenoic acid (5):
Triethyl amine (151g) & Malonic acid (103.8g) is charged in RBF under nitrogen atmosphere at RT, followed by addition of n-Hexanal (100 g) and stirred at 80°C, continued stirring the mixture for 4 hrs, cooled the mixture and added 800ml of 1N HCl and 500 ml of MTBE, stirred and separated both organic and aqueous layers, aqueous layer is extracted with MTBE (200ml), dried and distilled off the organic layer under vacuum to obtain 3E-Octenoic acid (130 g) with yield >95% and analyzed by GC with purity >90% .
Example 2. Synthesis of 3E-Octen-1-ol (4):
Charged Vitride (405 g) in RBF under nitrogen atmosphere at RT along with Toluene (400 ml), stirred and cooled to 10 °C, slowly added 3E-Octenoic acid (100 g) at 10°-15°C, stirred followed by addition of HCl solution (1.0Lt) and MTBE (200 ml), separated the MTBE layer and dried with sodium sulphate (20gr) and distilled off the MTBE layer under vacuum to obtain 3E-octen-1-ol (45 g) with yield >50% and analyzed by GC with purity >94.0%.

Example 3. Synthesis of 1-Chloro-3E-Octene (3):
Charged MDC(400ml) and 3E-Octene-1-ol(100g) in RBF and cooled 10 °C, added TEA(94.7g), and stirred, followed by addition of Thionyl chloride (120.8g), heated to reflux, and stirred for 4 hrs, then cooled to RT, quenched the mass in to water (400ml) and separated aqueous and organic layers, and extracted the aqueous layer with MDC (200ml), neutralized the MDC layer with 10% sodium bicarbonate solution 200ml, dried and distilled of MDC under vacuum to obtain 1-Chloro-3E-Octene (80gr) with Yield >70 % and analyzed by GC with Purity of >95.0 %.

Example 4. Synthesis of 5E-decenol (2):
Charged Magnesium turnings (18g) under nitrogen atmosphere and added THF(50ml) slowly into the reactor at 65°C under nitrogen atmosphere, and charged Iodine (0.5gr), 1,2-dibromoethane (1ml) and 1-chloro-3E-octene (100gr) in THF(100ml), stirred under reflux, and cooled the Grignard reagent to 30°C & charged THF(75gr) in another RBF purged ethylene oxide (75gr) and added to mass and at 10°C , stirred and quenched the mass with 10% Sulphuric acid solution, then separated both aqueous and organic layers, charged MTBE(200ml) to the aqueous layer for extraction, washed the combined MTBE and THF layers with brine solution(200ml), distilled off organic layer under vacuum to obtain 5E-decenol (48g) with yield >45.0% and analysed by GC with Purity of >95.0 %.

Example 5. Synthesis of 5E-Decenyl acetate (1):
Charged MDC (500 ml) and N,N Di methyl amino pyridine (DMAP) (8.0g) at RT and added 5E-Decenol (100 g) and cooled to 10°C, followed by slow addition of acetyl chloride (63.3g), stirred and added water(500ml), stirred and then separated both organic and aqueous layer, extracted MDC layer and distilled off organic layer under vacuum to obtain 5E-Decenyl acetate (90 g) with yield >72.0% and analyzed by GC with purity >95.0%
, Claims:
1. A novel method for synthesizing sex pheromone of peach moth (E)5-decenyl acetate is characterized by comprising the following steps: condensation of n-hexanal and Malonic acid in presence of base triethyl amine or DMF (N,N di-methyl formamide) to generate 3E-Octenoic acid; then reducing 3E-Octenoic acid in presence of Vitride or Sodium borohydride or Lithium aluminium hydride to obtain 3E-octen-1-ol; followed by chlorination using Thionyl chloride, or PCl3/POCl3; and then carrying out coupling of 1-chloro-3E-octene and ethylene oxide with Grignard reagents; finally carrying out acetylation of 5E-decenol using acetyl chloride or acetic anhydride to obtain (E) -5-deceny1 acetate.

2. The method of synthesis as claimed in claim 1, wherein the condensation is carried out in presence of triethylamine preferably.

3. The method of synthesis as claimed in claim 1, wherein the reducing agent utilized is Vitride.

4. The method of synthesis as claimed in claim 1, wherein the chlorination is carried out by Thionyl chloride preferably.

5. The method of synthesis as claimed in claim 1, wherein the acetylation is carried out by acetyl chloride preferably.

6. The method of synthesis as claimed in claim 1, wherein the coupling is carried out by known Grignard reagents.