Radiolabeled proteolytic degradation-resistant somatostatin analogues have been of long-standing interest as cancer imaging and radiotherapy agents for targeting somatostatin receptor-positive tumors. Our interest in developing (186)Re- and (188)Re-based therapeutic radiopharmaceuticals led to investigation of a new Re(V)-cyclized octreotide analogue, Re(V)-cyclized, thiolated-DPhe(1)-Cys(2)-Tyr(3)-DTrp(4)-Lys(5)-Thr(6)-Cys(7)-Thr(OH)(8) (Re-SDPhe-TATE) using both experimental and quantum chemical methods. The metal is directly coordinated to SDPhe-TATE through cyclization of the peptide around the [ReO](3+) core.
View Article and Find Full Text PDFSugars produced from photosynthesis in leaves are transported through the phloem tissues within veins and delivered to non-photosynthetic organs, such as roots, stems, flowers, and seeds, to support their growth and/or storage of carbohydrates. However, because the phloem is located internally within the veins, it is difficult to access and to study the dynamics of sugar transport. Radioactive tracers have been extensively used to study vascular transport in plants and have provided great insights into transport dynamics.
View Article and Find Full Text PDFA new route to 6-deoxy-6-fluorosucrose has been developed. The process proceeds in 8 linear steps in 25% overall yield from sucrose. The steps incorporating fluorine and subsequent deprotection are quite rapid, making the procedure useful in the context of F-labeling for PET applications.
View Article and Find Full Text PDFThe first chemical synthesis of 1'-deoxy-1'-fluorosucrose has been accomplished in eight steps from sucrose by an unlikely, but ultimately successful, SN2 displacement reaction.
View Article and Find Full Text PDFA facile synthesis of 6'-deoxy-6'-fluorosucrose has been developed. The title compound is available in six linear steps in 44% overall yield from commercially available sucrose. The synthesis involves rapid and convenient fluorination and deprotection conditions.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
July 2012
Intramolecular redox reaction: heating N-alkyl, N-allyl-, and N-benzyl-substituted S-alkenyl sulfoximines under appropriate conditions results in the formation of NH-S-alkyl sulfoximines. The intramolecular redox reaction involves a hydride transfer that occurs by a 6-endo-trig process. The intermediates in the reaction can also give access to four- and six-membered heterocyclic rings and a new class of chiral dienes.
View Article and Find Full Text PDFNew analogues of isomeric ellipticine derivatives fused with biologically important pyrroloindole or chromene moiety have been synthesized by utilizing an intramolecular imino Diels-Alder reaction in a single step.
View Article and Find Full Text PDFA new, efficient, and highly diastereoselective synthesis of polycyclic indole derivatives through intramolecular imino Diels-Alder reaction of aminoanthraquinone with N-prenylated indole-2-carboxaldehydes in the presence of 20 mol % of triphenylphosphonium perchlorate (TPPP) is reported with extremely high cis selectivity in good yield.
View Article and Find Full Text PDF