Dactimicin,* produced by Dactylosporangium matsuzakiense, is a new member of fortimicingroup antibiotic.1-3) Structurally, this antibiotic is the first aminoglycoside having a formimino moiety. We wish to report here the first synthesis of dactimicin (1). The starting material, 1,2'.6'-tri-N-Boc-fortimicin B4) (2) was prepared from fortimicin B by treatment with di-t-butyldicarbonate in the pre...

A chiral Pd(II)-bis(oxazoline) complex was found to be highly effective in promoting the first direct diastereo- and enantioselective addition of alkylazaarenes to N-Boc aldimines and nitroalkenes under mild conditions. Deprotection of Boc-protected products proceeded readily to provide amines in high yields.

In the presence of a Brønsted acid catalyst, both aldehydes and N-Boc-aminals were converted to enecarbamates and N-Boc-iminium salts as activated nucleophiles and electrophiles, respectively, giving unprecedented Mannich adducts. The asymmetric variant of the present Mannich reaction has also been demonstrated with a chiral phosphoric acid catalyst.

The tert-butyloxycarbonyl (Boc) group is one of the most widely used amine-protecting groups in multistep reactions synthetic organic chemistry as well peptide synthesis. Traditional methods to remove Boc have disadvantages terms high acidity, use expensive reagents, excessive amounts catalysts and harmful solvents temperatures, making them environmentally unsustainable. Therefore, more efforts...

Abnormal regulation of Sonic hedgehog (Shh) signaling has been described in a variety of human cancers and developmental anomalies, which highlights the essential role of this signaling molecule in cell cycle regulation and embryonic development. Gas1 and Boc are membrane co-receptors for Shh, which demonstrate overlapping domains of expression in the early face. This study aims to investigate ...

The modern satellite navigation system Galileo is developed by European Union. Galileo is a completely civil system that offers various levels of services especially for civil users including service with safety guarantee. Galileo system employs modern signal structure and modern BOC (Binary Offset Carrier) modulation. The Galileo Receiver is investigated in the frame of the GARDA project solve...

s p r i n g 2 0 0 7 www.insidegnss.com On-going discussions are taking place between U.S. and European Union (EU) experts concerning the future GPSIII L1C and Galileo E1 OS civil signals. An agreement on a common power spectral density (PSD) known as multiplexed binary offset carrier (MBOC) recently emerged as a solid candidate to replace the current baseline: BOC(1,1). In order to comply with ...

Several new Global Navigation Satellite System (GNSS) modulations adopt a Binary Offset Carrier (BOC) subcarrier to shape the signal spectrum, increase frequency separation and improve tracking performance. BOC modulated signals are however characterized by ambiguous multi-peaked correlation functions and several techniques have been proposed in the literature to solve the problem of locking in...

Holoprosencephaly (HPE) is caused by a failure to form the midline of the forebrain and/or midface. It is one of the most common human birth defects, but clinical expression is extremely variable. HPE is associated with mutations in the sonic hedgehog (SHH) pathway. Mice lacking the Shh pathway regulator Cdo (also called Cdon) display HPE with strain-dependent penetrance and expressivity, impli...

Pentosidine is a recently discovered fluorescent protein cross-link from human extracellular matrix that involves lysyl and arginyl residues in an imidazo (4, 5b) pyridinium ring. Pentosidine could be synthesized in vitro by the reaction of ribose, lysine, and arginine. The potential biological significance of the molecule prompted us to investigate its mechanism of formation from D-ribose and ...