SYNTHESIS OF TERT-BUTYLCYCLOPENTANE-FUSED PYRIMIDIN-4-ONES

In the reactions of ethyl S)-2-amino-4-tert-butyl-1-cyclopentanecarbo xylate (4) or ethyl S)-2-amino-4-tert-butyl-1-cyclopentanecarboxamide (6) or 5S)-3-tert-butyl-6-aza-bicyclo[3.2.0]heptan-7-one (2) with im idates or triethyl orthobenzoate. tert-butylcyclopentane-fused dihydro pyrimidin-4-ones (7a-e) were prepared. The azetidinone 2 with lactim e thers furnished pyrrolo-, pyrido- and azepino[1.2-a]pyrimidin-4-ones ( 8-10) in ring-enlargement reactions. The ethyl S)-2-amino-4-tert-buty l-1-cyclopentanecarboxylate (4) and ethyl -benzylamino-4-tertbutyl-1-c yclopentanecarboxylate (5) and potassium cyanate or phenyl isocyanate or potassium thiocyanate or phenyl isothiocyanate, yielded pyrimidine- 2,4-diones or 2-thioxopyrimidin-4-ones (11-22).