hcl aq and ethyl acetate ether 1 1 and chromatography silica gel ether 1 h nmr cdcl 3 9 2 broad s nh 8 6 broad s nh 7 81 dd 1h 7 48 dd 1h 6 89 m 1h 6 75 d 1h 6 69 m 1h 4 45 dd 1h 4 33 dd 1h 3 75 m 1h 2 61 m 1h 1 97 m 1h u2212 cis 1 4 7 difluoro 1 1a 2 7b tetrahydro cyclopropa c chromen 1 yl 3 5 ethynyl pyridin 2 yl urea was prepared analogously to example 1c but using cis 4 7 difluoro 1 1a 2 7b tetrahydro cyclopropa c chromene 1 carboxylic acid 100 mg 0 4 0 44 mmol and 5 trimethylsilanylethynyl pyridine 2 ylamine 93 mg 0 49 mmol to give 25 mg 17 the crude product was purified by extraction between 0 01 m hcl aq and ethyl acetat ether 1 1 and chromatography silica gel ether the mixture obtained containing the title compound together with silylated compound was stirred with bu 4 n f u2212 in 25 water in thf for 30 min and the chromatography was repeated to obtain pure u2212 cis 1 4 7 difluoro 1 1a 2 7b tetrahydro cyclopropa c chromen 1 yl 3 5 ethynyl pyridin 2 yl urea 1 h nmr cdcl 3 9 2 broad s nh 7 95 d 1h 7 59 dd 1h 7 48 broad s 1h 6 89 td 1h 6 64 td 1h 6 57 d 1h 4 46 dd 1h 4 33 dd 1h 3.