2-Chloro-1,1 ,2-trifluoroethyl ethyl

CHLORO-l,l,2-TRIFLUOROETHYL ETHYL ETHER (Ether, 2-chloro-l,l,2-trifluoroethyl ethyl)... 

Chloro-l,l,2-trifluoroethyl ethyl ether has been prepared by the base-catalyzed addition of ethanol to l-chloro-l,2,2-tri-fluoroethylene.3,4... 

Ethyl chlorofluoroacetate has been prepared by the action of sulfuric acid3 or of silica 4 on 2-chloro-l,l,2-trifluoroethyl ethyl ether. The procedure given here is essentially that of Young and Tarrant.3... 

Prepares solution of sodium methylate by dissolving 3.9 g of sodium metal in 500 ml of methanol. Add 39.0 g of 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazeplne-2-one. Evaporate the reaction mixture to a residue and dissolve the residue in 170 ml of dimethylformamide. Add 30 g of 2,2,2-trifluoroethyl Iodide and stir at room temperature for Vi hour, then heat to 60°C to 70°C for an additional 7 hours. Add 19 g of 2,2,2-trifluoroethyl iodide and resume the heating and stirring at 60°C to 70°C for an additional 16 hours. Filter off the solids and evaporate the filtrate to a residue in vacuo. Triturate the residue with water and extract with ethyl ether. Wash the ethereal extract with water, dry over anhydrous sodium sulfate and evaporate the solvent to a residue. 

C) Preparation of 2-Methyl-3-(2,2,2-Trifluoroethyl)Thiomethyl-6-Chloro-7-Sulfamyl-3,4-Dihydro-1,2,4-Benzothiadiazine-1,1-Dioxide To 4.6 g (0.015 mol) of 4-amino-2-chloro-5-(methylsulfamyl)benzenesulfonamide in 30 ml of the dimethyl ether of ethylene glycol is added 4.08 g (0.02 mol) of 2,2,2-trifluoroethylmercaptoacetaldehyde dimethylacetal followed by 1 ml of ethyl acetate saturated with hydrogen chloride gas. The resulting solution is refluxed for 1.5 hours, cooled and then slowly added to cold water dropwise with stirring. The crude product is filtered, dried and recrystallized from isopropanol (3.2 g), MP 202° to 202.5°C. A second recrystallization from isopropanol raised the MP to 202°... 

The reaction is mainly used to prepare dialkyl 3-cyano-2-propenylphosphonates, which are used as precursors for retinal and derivatives. Thus, diethyl and Z w(trifluoroethyl) 3-cyano-2-methyl-2-propenylphosphonates are conveniently prepared in good to excellent yields (75-90%) by heating at 180-200°C 4-chloro--- or 4-brorno-3-rncthylcrotonitriles- and the corresponding phosphite. Similarly, diethyl 3-cyano-2-butenylphosphonate is obtained in 95% yield from triethyl phosphite and 4-chloro-2-methylcrotonitrile (Scheme 6.31 ). In a further example, 4-bromo-3-methyl-2-hex-enenitrile has been reacted with triethyl phosphite at 170-180°C to prepare diethyl 3-cyano-2-methyl-l-ethyl-2-propenyIphosphonate in fair yield (44%).- The reaction of a polyfunctional iodide, 3-amino-2-(iodoacetyl)crotonitrile, with triethyl phosphite affords the expected 3-cyanoalkylphosphonate in 78% yield. 

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