No abstract

Both are air-stable.

Cyclopentadienyl(triethylphosphine)copper(1), CsHsCuP(C2Hs)3, has the cell dimensions a=8.60+ 0.02, b= 11.04+0.03, c= 7.67 + 0.02 ~ and fl= 115"3+0"05 °. The space group of the crystal is P2j/m and Z= 2. The structure was solved, using the intensities obtained from Weissenberg photographs, by three-dimensional Patterson, Fourier and least-squares methods to a final R index of 0.145 when a set of hydrogen atoms was included at chemically expected positions. The analysis revealed the presence of two enantiomers distributed apparently equally and randomly throughout the crystal. The C5H5 ring is n-bonded to the copper atom with average bond lengths of 2.24 for Cu-C and 1.38 A. for C-C. The Cu-P bond length is 2.14. The presence of a n-bonded C5H5 ring is in accord with the thermal stability of the compound. CsHsCuP(C2Hs)3 is monomeric and obeys the inert gas rule.

Arsenic trifluoride and iron pentacarbonyl react at 120 "C to give dark violet crystals of As,[Fe(CO),],with orthorhombic symmetry, space group Brnmb, cell dimensions a, = 10.82(2), bo = 10.96(2), and c, = 13.29(2) A, and z = 4.The structure was solved from photographic data by three-dimensional Patterson and Fourier methods and refined by least squares methods to R 0.1 07 for 630 independent reflections. The structure is disordered with one molecule randomly distributed in two orientations which are related by a crystallographic two-fold rotation axis.The idealized molecular symmetry is 3/17? (C,,). The molecule is characterized by an equilateral triangle of iron atoms, mean Fe-Fe 2.62(1) 8. The two arsenic atoms lie above and below the iron triangle, and are related by a mirror plane containing the iron atoms. Both arsenic atoms are bonded equally to the iron triangle, mean As-Fe 2.35 8.

Glipizide in a once daily formulation utilizing the gastrointestinal therapeutic system (GITS) has been shown in preliminary studies to improve insulin sensitivity as assessed with meal tolerance testing. To evaluate the ability of glipizide GITS to specifically improve clinical insulin sensitivity in vivo, a double-blind, placebo-controlled trial randomized 40 NIDDM subjects to either glipizide GITS or placebo. The study was designed to evaluate NIDDM subjects whose fasting blood glucose was <190 mg% and GHb <11% to avoid the adverse effects of hyperglycemia on insulin resistance and secretion. After screening, oral hypoglycemic agents were discontinued for one month, at which time a meal tolerance test with glucose and insulin response, glycated hemoglobin, and fructosamine were obtained. Insulin sensitivity (S I ) and glucose effectiveness (S g ) were determined with a 4-h frequently sampled intravenous tolerance test (modified minimal model -3rd phase insulin infusion) at baseline. Specific abdominal fat depots were quantitated by MRI scans. Patients were then randomized to receive placebo or active drug and all parameters were repeated at 1, 2, 5, and 8 months after randomization. Glipizide GITS significantly improved meal tolerance, reduced glycated blood proteins, and increased insulin sensitivity (P < .001). No change was seen for S G . There was no significant change in abdominal fat distribution during the trial.Glipizide GITS is effective in lowering glucose tolerance and improving insulin sensitivity without an increase in fasting insulin, weight gain, or change in abdominal fat composition. Drug Dev. Res. 44:1-7, 1998.