منابع مشابه
Synthesis of 2-Oxazolines by in Situ Desilylation and Cyclodehydration of β-Hydroxyamides.
A powerful method for the synthesis of 2-oxazolines from silyl-protected β-hydroxyamides is reported. Using diethylaminosulfur trifluoride (DAST) or its tetrafluoroborate salt (XtalFluor-E), silyl-protected β-amidoalcohols can be in situ deprotected and dehydrated to give 2-oxazolines in good yields. The utility of this approach was demonstrated by preparing the first reported oligomer of [2,4'...
متن کاملSynthetic explorations towards 3-deoxy-3-fluoro derivatives of D-perosamine.
Based on a literature precedent, preparation of methyl 4-azido-3,4,6-trideoxy-3-fluoro-alpha-D-mannopyranoside (18) was attempted via fluorination of methyl 4-azido-2-O-benzyl-4,6-dideoxy-alpha-D-altropyranoside with diethylaminosulfur trifluoride (DAST). Contrary to expectations, the reaction took place with retention of configuration at the site of the fluorination yielding methyl 4-azido-2-O...
متن کاملFar-infrared properties of DAST.
Using terahertz time-domain spectroscopy, we have measured the index of refraction and the absorption coefficient of the organic ionic salt 4-N, N-dimethylamino-4?-N?-methyl-stilbazolium tosylate (DAST). This promising organic electro-optic material exhibits strong absorption and dispersion for frequencies above 1 THz at both room temperature and 83 K. No reduction in the absorption strength is...
متن کاملDendrimer adjusted nanocrystals of DAST: organic crystal with enhanced nonlinear optical properties.
Organic crystals of trans-4-[4-(dimethylamino)-N-methylstilbazolium] p-tosylate (DAST) with enhanced nonlinear optical properties were successfully prepared at the nanometre scale due to the influence of a carbosiloxane dendrimer (CSiO-D).
متن کاملTunable terahertz-wave generation from DAST crystal by dual signal-wave parametric oscillation of periodically poled lithium niobate.
The first known demonstration of tunable terahertz-wave generation by difference-frequency generation of dual signal-wave quasi-phase-matched optical parametric oscillation was performed with periodically poled LiNbO(3) (PPLN) with a series of gratings. An organic ionic salt, 4-dimethylamino-N-methyl-4-stilbazolium-tosylate (DAST), was used as a nonlinear crystal. A compact terahertz-wave sourc...
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ژورنال
عنوان ژورنال: Synlett
سال: 2006
ISSN: 0936-5214,1437-2096
DOI: 10.1055/s-2006-939723