Azomethine ylides derived from dichlorocarbene and O-acylsalicylaldehyde anils in the synthesis of 2,5-epoxy-2,3,4,5-tetrahydro-1,4-benzoxazepin-2-ones and 2-aminoethanols
作者:I. V. Voznyi、M. S. Novikov、A. F. Khlebnikov、R. R. Kostikov
DOI:10.1023/b:rucb.0000041304.68814.83
日期:2004.5
Iminiodichloromethanides generated by the reaction of O-acylsalicylaldehyde anils with dichlorocarbene undergo regioselective intramolecular 1,3-dipolar cycloaddition to the ester carbonyl group to give 2,5-epoxy-2,3,4,5-tetrahydro-1,4-benzoxazepin-2-ones. These compounds are expedient precursors for the synthesis of N-(2-hydroxybenzyl)ethanolamines.
Carbon isotope fluctuations through the neoproterozoic-lower Cambrian Birmania basin, Rajasthan, India
作者:Anil Maheshwari、A. N. Sial、S. C. Mathur
DOI:10.1007/bf03175656
日期:2002.3
The results of a carbon isotope study from a hitherto unexplored marine sediments from the Birmania basin, Northwestern India are reported, which documents significant isotope variation across the Precambrian-Cambrian boundary (Pc/C). An attempt has been made to identify carbon isotope chronostratigraphic marker for the Precambrian-Cambrian boundary in the sedimentay succession. The transition is marked by a negative excursion during phosphoritic activity at the base of the Birmania succession which is followed by a positive excursion close to the boundary and a swing back to less positive values in the Early Cambrian. The characteristics of the paleoenvironment during the transition interval is also discussed.
Riemschneider,R.; Kampfer,H., Justus Liebigs Annalen der Chemie, 1963, vol. 665, p. 35 - 42
作者:Riemschneider,R.、Kampfer,H.
DOI:——
日期:——
REIMSCHNEIDER; GOEHRING; FROEMMING, Zeitschrift fur Naturforschung. Teil B: Chemie, Biochemie, Biophysik, Biologie, 1961, vol. 16 B, p. 704 - 704