0 u00b0 c to about 80 u00b0 c is preferred and of about 20 u00b0 c to about 40 u00b0 c is especially preferred it is preferred to carry out the reaction at atmospheric pressure but the specific pressure employed is not critical chloroform is consumed in the reaction of the process in the ratio of two moles per mole of compound of formula ii employed amounts about 2 to about 100 moles per mole of compound of formula ii are generally employed and from about 2 5 to about 10 moles are preferred any excess chloroform employed tends to drive the reaction toward completion the strong base is generally an alkali metal or quaternary ammonium hydroxide although any base which is sufficiently strong to convert a portion of the chloroform to its carbanion under the reaction conditions can be employed examples of useful bases include hydroxylic strong bases such as sodium hydroxide potassium hydroxide benzyl trimethylammonium hydroxide tetrabutylammonium hydroxide and the like the strong base can be added to the reaction mixture as a solid or as a solution in a solvent such as water in the latter case concentrations greater than 20 percent are preferred and concentrations greater than 40 percent are especially preferred one equivalent of strong base per mole of compound of formula ii is consumed in the reaction but an amount in excess of one equivalent is generally employed about 1 to about 20 equivalents are typical and about 2 to about.