th  - 1988 - 51st ENC Conference

82
BROADBAND PULSES FOR EXCITATION AND INVERSION IN I=i
SYSTEMS
D.P. Raleigh*, E.T. Olejniczak 2 and R.G. Griffin
Massachusetts Institute of Technology, Cambridge, MA 02139 U.S.A.;
2Abbott Park Laboratories, North Chicago, IL 60046.
New composite pulses for exciting and inverting three-level systems
are presented. The n/2-pulse is designed for use in quadrupole echo
spectroscopy and has a bandwidth comparable to existing sequences and
is slightly shorter. Two new broadband n-pulses are presented which
have bandwidths larger than other existing I=I inverting pulses without
being significantly longer. The composite n-pulses have bandwidths
exceeding + 2m .. Experimental examples and numerical calculations are
presented ~hic~ldemonstrate the usefulness of these sequences.
83
I
DEUTERIUM NATURAL ABUNDANCE NMR SPECTROSCOPY:
MONOTERPENE BIOSYNTHESIS, THE LINALOOL-LIMONENE CONNECTION
M.F. Leopold , William W. Epstein, and David M. Grant
Department of Chemistry, University of Utah
Salt Lake City, Utah 84112
The advent of high-field NMR has allowed the accurate and reproducible
measurement of relative deuterium intensities at natural abundance. Most recently
this technique has been applied to the biosynthesis of limonene in citrus and
the results supportlthe regiospeci~ic conversion of the proposed ~__-terpinyl
cation to limonene. Study of the -H NMR of limonene suggested the analysis of
an acyclic precursor such as linalool pyrophosphate. Both linalool acetate
and limonene have been isolated from oil of bergamot and studied to assess
continuity of relative deuterium integration and fractionation due to secondary
deuterium isotope effects.
.OPP
I. Leopold, M.F.; Epstein, W.W.; Grant, D.M.J. Am. Chem. Soc. 1988, ii0, 616.
140