1995 to Present: Eric J. Leopold Consulting, San Mateo,
Consulted on peptide-resin cleavages using halotrialkylsilanes
in the chemical process industry, organic synthesis and separation
1995 to 1999: RESEARCH ASSOCIATE TO WILLIAM S. JOHNSON,
CHEMISTRY DEPARTMENT, STANFORD UNIVERSITY, Stanford, California
Conducted experiments to demonstrate the fluorine atom as a
cation-stabilizing auxiliary in biomimetic polyene cyclization
studies. Synthesized cyclization precursors. Prepared manuscripts
1994 to 1995: PENINSULA LABORATORIES, Belmont, California,
Researched peptide-resin cleavage using trialkylhalosilanes.
Developed and optimized purification of bioactive peptides for
clinical trials. Lowered cost of peptide manufacturing through
introduction of HPLC ion exchange. Evaluated high performance
centrifugal partition chromatography for separations and purifications.
Modernized HPLC analytical and manufacturing protocols. Trained
chemists in chromatographic principles and proper use of equipment.
Prepared process SOP's.
1991 to 1994: ALPHA 1 BIOMEDICALS, INC., Foster City, California,
Discovered and developed new and practical methods for large
scale peptide-resin cleavage using trialkylhalosilanes and at
the same time, eliminated the side reactions of conventional mineral
acid peptide-resin cleavage. Produced peptides on a large and
small scale by solid phase synthesis under GMP. Developed method
of analysis for amino acid-peptide coupling for higher purity
in peptide synthesis. Developed and performed large scale sepa
ration and purification of bioactive peptides for clinical trials.
Improved existing ion exchange method of peptide purification.
Evaluated HPLC columns for optimum separations. Prepared process
SOP's. Trained process chemists in peptide synthesis and purification.
1984 to 1990: BECKMAN INSTRUMENTS, formally SMITHKLINE BECKMAN,
Palo Alto, California, RESEARCH CHEMIST
Developed process for FMOC anchoring group in peptide synthesis.
Synthesized fluoride ion cleavable silyl ether peptide-resin linkers.
Performed electroorganic synthesis of chiral peptide intermediates.
Perfected rapid large scale purification of peptide intermediates
by vacuum dry column chromatography. Carried out analysis by FT-NMR,
IR and UV. Evaluated PACE HPCE instrument. Demonstrated and perfected
amino acid chirality analysis of amino acids and peptides by HPLC
and capillary electrophoresis. Conducted methods development for
capillary electrophoresis. Researched and developed capillary
wall coatings for the elimination of electroosmosis in capillary
electrophoresis to give better separations.
1977 to 1984: CHEMISTRY DEPARTMENT, STANFORD UNIVERSITY,
Stanford, California, SENIOR RESEARCHER
In Collaboration with Dr. E. E. van Tamelen, 1980 to
1984, Discovered and perfected vacuum dry column chromatography.
Synthesized and radiolabeled candidate structures for squalene
biosynthesis. Carried out biogenetically patterned total synthesis
of steroids. Discovered efficient stereoselective synthesis of
homogeraniol. Demonstrated structure proof of 15-nor-18,19-dihydro
squalene-2,3-oxide enzymatic cyclization. Planned and executed
novel multistep syntheses
In Collaboration with Dr. W. S. Johnson, 1977 to 1980,
Conducted 20 step synthesis of intermediates for biomimetic cyclization
studies leading to dl-19-nor-4-pregnen-20-one. Investigated groups
as cyclization terminators in biomimetic cyclization studies.
Perfected dry column chromatography for analytical and preparative
separations. Performed micro and macro synthesis.
1973 to 1977: SELF EMPLOYED, Palo Alto, California
Continued research of thesis on steroid D-ring conformations
from new X-ray data while working as a wedding photographer, musician
and precious metals investor.
1967 to 1972: ELI LILLY AND CO., Indianapolis, Indiana,
SENIOR RESEARCH CHEMIST
Synthesized new insecticidal juvenile hormone mimics. Work
led to a patent. Developed new light stable pyrethroid insecticides.
Researched compounds for the chemical control of animal parasites.
Prepared test compounds for field trials. Trained and supervised
TECHNIQUES and INSTRUMENTS:
Preparative and analytical separations using wet, dry column,
vacuum dry column chromatography (for large scale separations),
TLC, HPLC (normal, reverse phase), SEC, ion exchange, HPCE, HPCPC,
and VPC. Distillation: spinning band, molecular (wiped film),
Kugelrohr. Reverse osmosis and standard methods of purification.
HPLC methods development. Spectrophotometer: IR, FT-IR, visible,
UV, FT-NMR. Dielectric constants and dipole moments. Computer
searching of Chemical Abstracts and other databases including
World Wide Web. Content,Web graphics and Web publishing.
Postdoctoral Fellowship with Dr. W. S. Johnson, Stanford
University, Stanford California.
Ph. D. in Organic Chemistry, University of Pennsylvania,
B.S. in Chemistry, Drexel University (cooperative education
plan (work-study)), Philadelphia, Pennsylvania.
The Fluorine Atom as a Cation-Stabilizing Auxiliary in Biomimetic
Polyene Cyclizations. Total Synthesis of dl-Dammarenediols. J.
Org. Chem., 1999, 64, 9587-9595
and Deprotection of Peptide Resins Using Chloro and Bromotrialkyl
silanes., Peptide Res. 1995, 8, 298-300
and Deprotection of Peptides from MBHA-Resin with Bromotrialkyl
silane. Tetrahedron Lett., 1993, 34, 7713-7716
Cleavage and Deprotection of Peptides on MBHA-Resin with
Hydrogen Bromide. Int. J. Peptide Protein Res.,1992,
Separation of Chiral Amino Acids and Peptides by Capillary
Electrophoresis with P/ACE 2000. Spectra 2000 [Deux Mille],
1991, 156, 27-28
Free Solution Capillary Electrophoresis and Micellar Electrokinetic
Resolution of Amino Acid Enantiomers and Peptide Isomers with
L-and D-Marfey's Reagents. J. Chrom., 1990, 516, 241-249
Presqualene Alcohol, Squalene, and Sterol Biosynthesis from
Bifarnesol. Exp. Mycol., 1990, 14 (1), 74-77
Chiral Analysis of Amino Acids by Capillary Electrophoresis.
Application Data, DS-737, Beckman Instruments, Palo Alto,
Analysis of Chirality of Amino Acids and Peptides by High
Performance Capillary Electrophoresis. HPCE., J. Cell Biol.,
1988, 107 (6 Part 3) 217A
Separation of Chiral Amino Acids and Peptides by Capillary
Zone Electrophoresis. 1988 Federation of American Societies
For Experimental Biology 1988, 2 (6) Abstract 8559
Presqualene Alcohol from Gibberlla Fujikuroi. Phytochemistry,
1988, 27 (2), 628-629
Hydroboration of a 1,3,7-Triene: Homogeraniol. Organic
Syntheses, Coll. Vol. 7, p.258 (1990); Vol. 64, p.164 (1986).
Mechanism of Presequalene Pyrophosphate-Squalene Biosynthesis
II. Synthesis of Bifarnesol. Tetrahedron Lett., 1985,
Total Synthesis of d,l-Androst-4-ene-3-one-17-carboxylic
Acid. J. Chem. Soc., Chem. Commun.,1984,721-723
Action of 2,3-Oxidosqualene Lanosterol Cyclase on 15'-Nor-18,19-dihydro-2,3-oxido-squalene.
J. Am. Chem. Soc., 1982, 104, 6479-6480. See also Chemical
& Engineering News, 1982, 60, (47) 32
Vacuum Dry Column Chromatography. J. Org. Chem., 1982,
trans-4,8-Dimethyl-1,7-nonadienes. U. S. Patent 3,923,832.
December 2, 1975
Cyclization of 4-(trans-3,7-Octadienyl)-3-methyl-2-cyclohexen-1-ol
and 4-(trans,-trans-7-Methyl 3,7,11-dodecatrienyl)-3-methyl-2-cyclohexen-1-ol.
J. Am. Chem. Soc., 1974, 96, 2540 -2549
Allylic Cation Promoted Olefinic Cyclizations. The Sterospecific
Formation of a Tricyclic System and the Total Synthesis of d,l-Fichtelite.
J. Am. Chem. Soc., 1968, 90, 5872 -5881
Steroid Ring D Torsional Angles and Conformations from X-ray
Data. J. Am. Chem. Soc., 1966, 88, 3156-3157
Torsional Angles in Substituted Cyclopentanes. Ph. D.
Phosphorous Derivatives of Fatty Acids. The Addition of
Dialkyl Phosphonates to Unsaturated Acids and the Synthesis of
Some 11- Dialkylphosphonoundecanoamides. J. Am. Oil Chem.
Soc., 1965, 42, 134-136
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