by methods well known to those of ordinary skill in the art a compound of the formula vii can be prepared by treating a compound of the formula ix with formaldehyde at a temperature of about u2212 10 u00b0 c to about 10 u00b0 c preferably about 0 u00b0 c for about 5 to about 25 minutes preferably about 10 minutes and then treating with methanol followed by an excess of alkaline metal carbonate preferably potassium carbonate stirring for about 0 5 to about 2 hours preferably about 1 hour and then separating the liquid phase additional alkaline metal carbonate preferably potassium carbonate may be added to the liquid phase and the reaction mixture stirred at room temperature for up to about 72 hours to ensure completeness of reaction scheme 3 refers to the preparation of a compound of the formula i wherein n 0 in step 1 of scheme 3 a compound of the formula vii which is a precursor of the compound 1 is prepared from a compound of the formula x and a compound of the formula vii by mixing the compound of the formula x with the compound of the formula vii in a chlorinated hydrocarbon solvent such as chloroform dichoroethane dce or methylene chloride preferably methylene chloride the stirred mixture is cooled to about u2212 5 u00b0 c to about 5 u00b0 c.