elected from the groupconsisting of C3-C10 cycloalkyl, C5-C10 cycloalkenyl, C4-C9 saturated heterocyclyl, and C4-C9 partially saturated heterocyclyl, wherein each ring carbon may be optionally substituted with R.sub.33, a ring carbon other than the ring carbon at the point ofattachment of B to A may be optionally substituted with oxo provided that no more than one ring carbon is substituted by oxo