Biomimetic syntheses of syncarpurea

Simple syntheses of syncarpurea (1) from syncarpic acid and the amino acids ornithine or citrulline are presented.     

A selective gas chromatographic detector for polynuclear aromatics based on ultraviolet fluorescence

A vapor-phase fluorescence detector for the analysis of mixtures of polynuclear aromatic ring systems has been developed. This system utilizes wide bandpass excitation and wide band emission filters, thus increasing sensitivity and decreasing the complexity of previously designed instruments. The sensitivity of the detector has been demonstrated to be at the nanogram level with reasonable precision.     

Studies of the oxovanadium-organophosphonate system: Hydrothermal synthesis and crystal structure of the mixed valence cluster [V5O9(PhPO3)3(PhPO3H)2]2− and a comparison to the structure of the fully oxidized parent cluster [V5O7(OCH3)2(PhPO3)5]1−

The room temperature reaction of (Bu₄N)₃V₅O₁₄ with PhPO₃H₂ in methanol yields the pentanuclear V(V) cluster (Bu₄N)[V₅O₇(OCH₃)₂(PhPO₃)₅]·CH₃OH (1·CH₃OH). In contrast, the hydrothermal reaction of (Ph₄P) [VO₂Cl₂], PhPO₃H₂ and (NH₄)H₂PO₄ at 125°C for 96 hr yields the mixed valence V(IV)/V(V) species (Ph₄P)₂[V₅O₉(PhPO₃)₃(PhPO₃H)₂] (3). While the anions of both 1 and 3 exhibit a pentanuclear core, the structural consequences of 1-electron reduction of the fully oxidized cluster of 1 to produce 3 are quite dramatic, including reduction in coordination numbers at two vanadium sites and protonation of two phosphonate oxygen sites with concomitant structural reorganization. Crystal data: 1, monoclinic P2₁/n,a=12.167(2) Å,b=23.348(5) Å,c=22.508(5) Å,β=98.49(2)°,V=6323.9(19) ų,Z=4,D _calc=1.558 g cm^?3; 3, triclinic, $P\bar 1$ ,a=13.478(3) Å,b=14.399(3) Å,c=23.638(5) Å,α=72.53(2)°,β=85.58(2)°,γ=69.88(4)°,V=4107.0(16) ų,Z=2, D_calc=1.479 g cm^?3.     

Gilmicolin and Mycorrhizinol,Two New Metabolites of Gilmaniella humicolaBARRON

The structure of gilmicolin and mycorrhizinol, two new metabolites isolated from culture filtrates of Gilmaniella humicola BARRON , have been shown to be 3 and 15 respectively by spectral and chemical studies. The X-ray analysis of gilmicolin ( 3 ) is also reported.     

The synthesis and structure of bis(acetonitrile)nitrosyl tris(3,5-dimethylpyrazolyl)borato molybdenum hexafluorophosphate

Summary Treatment of [Mo{HB(3,5-Me₂C₃HN₂)₃}(NO)I₂] with one or two moles of AgPF₆ in acetonitrile afforded the paramagnetic (one unpaired electron) complex [Mo{HB(3,5-Me₂C₃NH₂)₃}(NO)(NCMe)₂][PF₆]. The structure of this complex was determined crystallographically, and the six-coordinate geometry of the complex cation confirmed.