Zobrazeno 1 - 10
of 380
pro vyhledávání: '"John E. Baldwin"'
Autor:
John E. Baldwin, Bruce S. Hudson
Publikováno v:
Journal of Physical Organic Chemistry. 27:213-217
Bicyclo[3.1.1]hept-2-ene was first prepared and well identified in 1972. In 1974, the degenerate thermal isomerization involving 1-d- and 3-d-bicyclo[3.1.1]hept-2-ene was approached successfully, as one of the two deuterium-labeled structures was sel
Autor:
Sylvia Zohrabian, Ryan M. Bell, William Hancock-Cerutti, George R. Mann, Phyllis A. Leber, John E. Baldwin, Matthew F. Wipperman
Publikováno v:
The Journal of Organic Chemistry. 77:3468-3474
cis,anti,cis-Tricyclo[7.4.0.0(2,8)]tridec-10-ene (13TCT) undergoes [1,3] sigmatropic rearrangements at 315 °C in the gas phase to the si product 1 and to the sr product 2 with si/sr = 2.1. The dominant thermal isomerization process, however, is epim
Autor:
Edward J. O’Neil, John E. Baldwin
Publikováno v:
Journal of Labelled Compounds and Radiopharmaceuticals. 52:427-430
Three stable isotope-labeled ethylcyclopropanes have been synthesized in preparation for a mechanistic study of its fragmentation to methane and butadiene. Two tactical innovations have been used to deal with practical synthetic challenges posed by t
Autor:
Stephanie R. Singer, John E. Baldwin
Publikováno v:
Canadian Journal of Chemistry. 86:395-400
An efficient four-step synthetic route from each of four crystalline isotopically labeled (1R)-menthyl (1S,2S)-(+)-2-phenylcyclopropanecarboxyates of better than 99% enantiomeric excess has provided multi-gram quantities of the corresponding chiral p
Publikováno v:
Astronomy & Astrophysics. 480:589-597
Aims. We investigate the properties of astronomical images made by combining the best images selected from a sequence of shortexposure frames (Lucky Imaging); we assess the match between modelling and observation and discover what variations in seein
Autor:
Phyllis A. Leber, John E. Baldwin
Publikováno v:
Org. Biomol. Chem.. 6:36-47
Molecular rearrangements through thermal [1,3] carbon shifts, such as vinylcyclopropane-to-cyclopentene and vinylcyclobutane-to-cyclohexene isomerizations, were recognized and exemplified repeatedly from 1960-1964. Serious mechanistic studies of thes
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 382:1639-1642
We present a final unified catalogue for the 7C survey at 151 MHz with resolution 70 × 70 cosec(δ) arcsec 2 . This has been constructed by amalgamating the existing catalogues derived from individual fields imaged at this resolution and eliminating
Autor:
John E. Baldwin
Publikováno v:
Journal of Labelled Compounds and Radiopharmaceuticals. 50:947-960
Questions bearing on just how organic chemical structures are converted to other compounds can be addressed in numerous ways through syntheses and studies of appropriately designed stable–isotope-labeled analogs. Most of the examples in the present
Autor:
John E. Baldwin, David C. Powers, Sarah S. Gallagher, Lynne A. Mccullough, Phyllis A. Leber, Andrew T. Higgs
Publikováno v:
The Journal of Organic Chemistry. 72:187-194
At 300 degrees C, bicyclo[4.2.0]oct-2-ene (1) isomerizes to bicyclo[2.2.2]oct-2-ene (2) via a formal [1,3] sigmatropic carbon migration. Deuterium labels at C7 and C8 were employed to probe for two-centered stereomutation resulting from C1-C6 cleavag
Autor:
John E. Baldwin
Publikováno v:
Journal of Physical Organic Chemistry. 19:884-888
The stereochemical and mechanistic aspects of the degenerate thermal isomerizations available to deuterium-labeled Z-ethylidene-2-methylcyclobutanes remain incompletely defined. Relevant data and several conjectural readings of the data are reconside