| R- (+)-haloxyfop-methyl, methyl R-2- (4-chloro-5- (trifluoromethyl) pyridin-2-yloxy) phenoxy) propionate, is a herbicide with highly biologic activity. Synthetical methods of R- (+)-haloxyflop-methyl started from S-(-)-lactic acid, hydroquinone and 2,3-dichloro-5-trifluoromethyl- pyridine were studied and synthetical conditions were optimized, R- (+)-haloxyflop-methyl was identified by elementary analysis, IR, 1H-NMR, GC-MS and polarimetry.In presence of catalyst triethylamine, S- (-)-methyl lactate was obtained through the esterifying between S- (-)- lactate and methanol in cyclohexane. The amount of added catalyst accounts for 4 per cent of total mass. When molar ratio n(S-(-)-lactic acid ):n (methanol) =1/2.6, reactive refluxing for 2.5 h, the yield was 91%. The e.e% reached 92%. Formed water was constantly removed. After completion of the reaction, the residue was cooled and filtrated. The saturated sodium bicarbonate solution was added to the residue to adjust the solution to neutral point. The residue was distilled off in vacuum. Anhydrous sodium sulfate was added to. The desired product of S-(-)-methyl lactate was obtained. The product was identified by polarimetry, density, refractive index, GC and IR.In presence of catalyst triethylamine, R- (-)-methyl toluene-4-sulfonyl lactate was obtained through the acylating between S- (-)-methyl lactate and toluene-4-sulfonyl chloride in dichloromethane. Diluted toluene-4-sulfonyl chloride with dichloromethane was added to S-(-)-methyl lactate at 0~5℃, and reacts for1 h at 0~5℃, for 2 h in room temperature. The reaction mixture was poured into cold water. The organic phase was separated, washed with saturated sodium bicarbonate and dried with anhydrous sodium sulfate. The solvent was recycled by distillation in vacuum. The desired product R- (-)-methyl toluene-4-sulfonyl lactate was obtained and identified by polarimetry, melting point and IR. The yield was 95%. The value of e.e% reached 95%. After flushing with nitrogen, R- (+)-methyl 2-(4-hydroxyphenoxy) propionate was obtained through the ester exchange between R- (-)-methyl toluene-4-sulfonyl lactate and hydroquinone in methanol. R- (-)-methyl toluene-4-sulfonyl lactate was added to the mixtures including hydroquinone and sodium hydroxide. After completion of adding, the reaction mixture reacted for 1 h at 10℃ , for 2 h at 30℃, then was cooled to10℃ and hydrogen chloride was introduced to acidify the reaction system. The reaction did not complete until the reaction mixture became transparent when the value of pH reached 6~7. Methanol was distilled off under atmosphere pressure. The residue was extracted with toluene. The toluene layer was washed with 5% sodium hydrogen carbonate solution, then with water and dried with anhydrous sodium sulfate. Toluene was distilled in vacuum and desired substance R- (+)-methyl 2-(4-hydroxyphenoxy) propionate was obtained. The product has been identified by polarimetry. [α]D25 is +31.7o, e.e% 86% and yield 80%.R- (+)-haloxyfop-methyl was obtained through the etherifying between R-(+)-methyl-2-(4-hydroxyphenoxy) propionate and 2,3-dichloro-5-trifluoromethyl- pyridine. Diluted methyl R- (+)-2-(4-hydroxyphenoxy) propionate with DMSO was added to DMSO, 2,3-dichloro-5-trifluoromethyl-pyridine through important intermediates tetrabutyl-ammonium bromide used as phase transfer catalyst and powered anhydrous potassium carbonate used as bound acid reagent. The amount of added tetrabutyl-ammonium bromide accounts for 4 per cent of total mass. The amount of added powered anhydrous potassium carbonate accounts for 4 times of total mass. The mixture was reacted for 37 h at room temperature. The organic phase was separated and dried with anhydrous sodium sulfate. Et2O was recycled by distillation; R- (+)-haloxyfop-methyl was obtained and identified by elementary analysis, IR, 1H-NMR, GC-MS and polarimetry. The yield was 88%, [α]D25 +24.3o, e.e% 76.9% and mass content 94%...
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