1n hcl 105 ml the thf layer was concentrated at reduced pressure to a volume of about 40 ml to yield the title compound ivb wherein r 3 is cyclopropyl to the concentrated solution from the previous step containing compound ivb was added an aqueous solution of naoh 2n 25 ml and meoh 175 ml the mixture was refluxed at 80 u00b0 81 u00b0 c for 2 hours the mixture was cooled to 50 u00b0 c maximum meoh was stripped off at reduced pressure and diluted with water 90 ml acidification of the solution was done at 10 u00b0 c by careful addition of 2n hcl ph 6 ethyl acetate 200 ml was added and the mixture was vigorously agitated while further acidifying to ph of 4 the ethyl acetate layer was separated from the aqueous one a solution of nh 4 oh and meoh 1 1 10 ml was slowly added in over 30 minutes at 22 u00b0 25 u00b0 c the precipitates were stirred at 25 u00b0 c for 1 5 hour cooled to 5 u00b0 c and stirred at this temperature for 30 minutes filtration followed by washing with cold ethyl acetate 25 ml and drying in vacuum at 35 u00b0 c afforded the ammonium salt v the crude ammonium salt v from the previous step 10 g 0 022 moles was suspended in toluene 350 ml the mixture was heated and stirred at 105 u00b0 c under a sweep of nitrogen for 5 hours the solution was cooled at 35 u00b0 c activated charcoal 0 5 g was added stirred for 0 35 hour.