Raymundo Cruz

Synthesis of the mannosyl erythritol lipid MEL A; confirmation of the configuration of the meso-erythritol moiety

Abstract The total synthesis of the two possible diastereomers of mannosylerythritol lipid A, a novel biosurfactant from Candida antartica T-34 with promising anti-proliferative properties in several cell lines, is described. By comparison with an authentic sample, the natural material is confirmed as a single diastereomer with the 4-O-(β- d -mannopyranosyl) d -erythritol configuration.

Anterior pituitary pyroglutamyl peptidase II activity controls TRH-induced prolactin release

Ecto-peptidases modulate the action of peptides in the extracellular space. The relationship between peptide receptor and ecto-peptidase localization, and the physiological role of peptidases is poorly understood. Current evidence suggests that pyroglutamyl peptidase II (PPII) inactivates neuronally released thyrotropin-releasing hormone (TRH). The impact of PPII localization in the anterior pituitary on the endocrine activities of TRH is unknown. We have studied whether PPII influences TRH signaling in anterior pituitary cells in primary culture. In situ hybridization (ISH) experiments showed that PPII mRNA was expressed only in 5-6% of cells. ISH for PPII mRNA combined with immunocytochemistry for prolactin, beta-thyrotropin, or growth hormone, showed that 66% of PPII mRNA expressing cells are lactotrophs, 34% somatotrophs while none are thyrotrophs. PPII activity was reduced using a specific phosphorothioate antisense oligodeoxynucleotide or inhibitors. Compared with mock or scrambled oligodeoxynucleotide-treated controls, knock-down of PPII expression by antisense targeting increased TRH-induced release of prolactin, but not of thyrotropin. Similar data were obtained with either a transition-state or a tight binding inhibitor. These results demonstrate that PPII expression in lactotrophs coincides with its ability to control prolactin release. It may play a specialized role in TRH signaling in the anterior pituitary. Anterior pituitary ecto-peptidases may fulfill unique functions associated with their restricted cell-specific expression.

Synthesis and experimental study of through-space hydrogen-fluorine and carbon-fluorine spin-spin coupling in 4,5-substituted 1-acetyl-8-fluoronaphthalenes.

The synthesis and NMR study (1H, 13C, and 19F) of a complete series of 4,5-substituted 1-acetyl-8-fluoronaphthalenes are reported. This data revealed a 6J(H,F) and a 5J(C,F) through space coupling between the fluorine and the methyl on the acetyl group (1H and 13C). The magnitude of this coupling constant changes depending on the nature of the substituent at C-4, the internuclear distance, and the solvent.

Cyclic and linear oligomerization reaction of 3,4,5-trimethoxybenzyl alcohol with a bentonite-clay

Abstract The catalytic induction and structures of cyclic and linear oligomers from 3,4,5-trimethoxybenzyl alcohol with a bentonite clay as catalyst are discussed.

X-ray crystal structure and1H-NMR chiral shift reagent study of a crown trimer

Abstract3,4,5-Trimethoxybenzyl alcohol was cyclooligomerized with a bentonite clay used as a catalyst. Results of the crystal structure analysis of the racemic (±) nonamethoxy[1,1,1]orthocyclophane trimer, C30H36O9, are described. The structure was determined by X-ray diffraction at 293 K and shown to belong to the triclinic space group P

Synthesis of 4-substituted 2-phenylaminothiazoles from amidines. A convenient route to 4-trichloromethylthiazoles.

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Synthesis of Phenylthiomethyl Compounds from Trichloromethyl Derivatives

. The compound possesses a distorted crown conformation with unusual C−H...O intermolecular interactions, and with a crystal packing not observed before in other related derivatives. The racemic mixture was also discriminated in its two enantiomeric isomers, using proton NMR and Eu(III) as a chiral shift reagent.

3,3',5'-triiodo-L-thyronine reduces efficiency of mRNA knockdown by antisense oligodeoxynucleotides: a study with pyroglutamyl aminopeptidase II in adenohypophysis.

The synthesis and characterisation of a novel complex formed by crown ether 2 and 2 molecules of fullerene C60 is reported.