Dale F Shellhamer - Academia.edu (original) (raw)

Papers by Dale F Shellhamer

Chemischer Informationsdienst, 1978

Concerted reactions are indicated for the electrophilic addition of chlorosulfonyl isocyanate wit... more Concerted reactions are indicated for the electrophilic addition of chlorosulfonyl isocyanate with monofluoroalkenes. A vinyl fluorine atom on an alkene raises the energy of a step-wise transition state more than the energy of the competing concerted pathway. This energy shift induces CSI to react with monofluoroalkenes by a one-step process. The low reactivity of CSI with monofluoroalkenes, stereospecific reactions, the absence of 2:1 uracil products with neat fluoroalkenes and quantum chemical calculations support a concerted pathway.

Journal of Agricultural and Food Chemistry

Acrolein hydrolysis byproducts are a part of good industrial stewardship practice. Aqueous acrole... more Acrolein hydrolysis byproducts are a part of good industrial stewardship practice. Aqueous acrolein is used worldwide as an industrial raw material, an herbicide, an oilfield biocide, a hydrogen sulfide scavenger, and a molluscicide. Industrial acrolein is obtained by the catalytic oxidation of propylene followed by aqueous absorption and then by distillations. Generally, the fate of aqueous acrolein is described as occurring by hydrolysis, evaporation, absorption into the ground, and its consumption by the intended application purposes and conditions. Measurements of acrolein in water are normally confined to its loss. However, its byproducts are rarely discussed. In this study, an aged acrolein solution has been found to contain byproduct aldehydes, including the major soluble 5,6-dihydro-2H-pyran-3-carboxaldehyde. Despite acrolein's facile hydrolysis degradation, this byproduct is surprisingly stable in aqueous media for at least 25 years at ambient temperatures. The presence of this byproduct has been established by 1H and 13C NMR, using DEPT, COSY, and HMBC, and UV spectroscopy at λmax 229 nm in natural water systems.

The Journal of …, 1985

... Basic Chemical Research Section, Air Force Rocket Propulsion Laboratory (AFSC), Edwards AFB, ... more ... Basic Chemical Research Section, Air Force Rocket Propulsion Laboratory (AFSC), Edwards AFB, California 93523 Gene E. Heasley Department of Chemistry, Bethany Nazarene College,Bethany, Oklahoma 73008 Received November 2, 1984 ...

Results in Chemistry

Abstract Line-broadening by NMR is an easy and fast method to detect radical intermediates in sol... more Abstract Line-broadening by NMR is an easy and fast method to detect radical intermediates in solution. Chlorosulfonyl isocyanate reacts with electron-rich alkenes via a Single Electron Transfer pathway to give 1,4-diradical intermediates. The Triplet 1,4-diradical can change to the Singlet species at lower temperatures. Less reactive alkenes proceed via a concerted pathway.

ChemInform, 1997

Addition Reactions of Alkenes with Electronegatively Substituted Alcohols in the Presence of Xeno... more Addition Reactions of Alkenes with Electronegatively Substituted Alcohols in the Presence of Xenon Difluoride.-A variety of fluoro-, alkoxy-and alkoxyfluoro-substituted products of addition of alkoxyxenonfluoride intermediates to the model alkenes norbornene, 2-methylpent-1-ene and hex-1-ene are formed depending on the conditions. Selectivity between the various reaction paths is observed to be a sensitive function of especially solvent, temp., and catalyst. The regio-and stereochemistry of the products of norbornene substitution reveals insight into the mechanistic pathways occurring in such electrophilic additions.

The Journal of Organic Chemistry, Jun 1, 2003

Ionic reactions of terminal alkenes with chlorine (Cl(2)), bromine (Br(2)), and iodine monochlori... more Ionic reactions of terminal alkenes with chlorine (Cl(2)), bromine (Br(2)), and iodine monochloride (ICl) are sensitive to the alkyl substituents, and the positions and number of vinyl fluorine atoms. These perturbations influence the symmetry of the halonium ion intermediates, which can be determined by the distribution of the Markovnikov to anti-Markovnikov products. A vinyl fluorine on the number-2 carbon favors an unsymmetrical intermediate with greater charge on the number-2 carbon unless the alkyl group is electron withdrawing. A vinyl fluorine on the terminal number-1 carbon favors positive charge development on that carbon unless a resonance stabilizing group is on the number-2 carbon. The symmetry of halonium ions with vinyl fluorines on both carbons-1 and -2 depends primarily on the characteristics of the alkyl substituent. Intermediates range from open-ions with the positive charge on carbon-2, to various bridged species, to open-ions on the terminal carbon.

... 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dale Shellhamer, David Gleason, Sean... more ... 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dale Shellhamer, David Gleason, Sean Rodriguez, & Victor Heasley (Point Loma Nazarene 5d. PROJECT NUMBER ... Dale F. Shellhamer*, David C. Gleason, Sean J. Rodriguez, Victor L. Heasley ...

The Journal of Organic Chemistry, 2013

Chlorosulfonyl isocyanate (CSI) is reported to react with hydrocarbon alkenes by a stepwise dipol... more Chlorosulfonyl isocyanate (CSI) is reported to react with hydrocarbon alkenes by a stepwise dipolar pathway to give N-chlorosulfonyl-β-lactams that are readily reduced to β-lactams. Substitution of a vinyl hydrogen for a vinyl fluorine changes the dynamics for reaction with CSI so that a concerted pathway is favored. Rate constants were measured for reactions of CSI with monofluoroalkenes and some hydrocarbon alkenes. Activation parameters for two hydrocarbon alkenes and two monofluoroalkenes support this change in mechanism. A plot generated from the natural log of rate constants vs ionization potentials (IP) indicates that fluoroalkenes with IP values >8.9 eV react by a concerted process. Electron-rich monofluoroalkenes with IP values <8.5 eV were found to react by a single-electron transfer (SET) pathway. Hydrocarbon alkenes were also found to react by this dipolar stepwise SET intermediate rather than the previously accepted stepwise dipolar pathway. Data support a pre-equilibrium complex on the reaction pathway just before the rate-determining step of the concerted pathway and a SET intermediate for the stepwise reactions. When the reactions are carried out at lower temperatures, the equilibrium shifts toward the complex or SET intermediate enhancing the synthetic utility of these reactions. Kinetic data also support formation of a planar transition state rather than the orthogonal geometry as reported for ketene [2 + 2] cycloadditions.

Results in Chemistry, 2020

Paper is free on-Line at: https://doi.org/10.1016/j.rechem.2019.100015

The Journal of Organic Chemistry, 1999

Interhalogen fluorides (XF; X ) I, Br, or Cl) generated from xenon difluoride (XeF 2 ) or triethy... more Interhalogen fluorides (XF; X ) I, Br, or Cl) generated from xenon difluoride (XeF 2 ) or triethylamine trihydrofluoride (TREAT HF) with iodine (I 2 ), N-halosuccinimides (NXS; X ) I, Br, or Cl), or alkylhypohalites (ROX; R ) CH 3 or t-Bu, X ) Br or Cl) with alkenes and aromatics are reported. A comparison of the above reactions with other methods reported in the literature to generate interhalogen fluorides is made. Interhalogens generated from direct action of elemental fluorine (F 2 ) or XF 3 (X ) I, Br, or Cl) with chlorine (Cl 2 ), bromine (Br 2 ), or iodine (I 2 ) give a species that can react with electron-deficient alkenes or aromatics. These reagents are too reactive for electronrich substrates. Interhalogen fluorides from reagents like NXS or ROX with XeF 2 or amine HF are much less reactive and give good yields with electron-rich akenes or aromatics.

Iodine monofluoride, generated from XeF 2 and I 2 or NIS, reacts with alkenes to furnish iodofluo... more Iodine monofluoride, generated from XeF 2 and I 2 or NIS, reacts with alkenes to furnish iodofluorinated products [cf. (II), (IV), (V)] in good yields. The reaction of aromatics with XeF 2 and I 2 or NIS proceeds as electrophilic aromatic iodination [→ (VII), (IX)]. Iodine monofluoride (IF), generated from XeF 2 proves to be less reactive than IF generated from I 2 and fluorine gas. -(SHELLHAMER, D. F.; JONES, B. C.; PETTUS, B. J.; PETTUS, T. L.; STRINGER, J. M.; HEASLEY, V. L.; J.

Journal of Fluorine Chemistry, 1998

Reaction of xenon difluoride (XeF2) and iodine (I2) or N-iodosuccinimide (NIS) with alkenes gives... more Reaction of xenon difluoride (XeF2) and iodine (I2) or N-iodosuccinimide (NIS) with alkenes gives iodofluoro products in good yields. Aromatics react with XeF2 and I2 or NIS to undergo electrophilic aromatic iodination. Iodine monofluoride (IF) generated from XeF2 is less reactive than IF generated from I2 and fluorine gas. This difference in reactivity suggests that the interhalogen IF is delivered

ChemInform, 1995

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chemischer Informationsdienst, 1978

Concerted reactions are indicated for the electrophilic addition of chlorosulfonyl isocyanate wit... more Concerted reactions are indicated for the electrophilic addition of chlorosulfonyl isocyanate with monofluoroalkenes. A vinyl fluorine atom on an alkene raises the energy of a step-wise transition state more than the energy of the competing concerted pathway. This energy shift induces CSI to react with monofluoroalkenes by a one-step process. The low reactivity of CSI with monofluoroalkenes, stereospecific reactions, the absence of 2:1 uracil products with neat fluoroalkenes and quantum chemical calculations support a concerted pathway.

Journal of Agricultural and Food Chemistry

Acrolein hydrolysis byproducts are a part of good industrial stewardship practice. Aqueous acrole... more Acrolein hydrolysis byproducts are a part of good industrial stewardship practice. Aqueous acrolein is used worldwide as an industrial raw material, an herbicide, an oilfield biocide, a hydrogen sulfide scavenger, and a molluscicide. Industrial acrolein is obtained by the catalytic oxidation of propylene followed by aqueous absorption and then by distillations. Generally, the fate of aqueous acrolein is described as occurring by hydrolysis, evaporation, absorption into the ground, and its consumption by the intended application purposes and conditions. Measurements of acrolein in water are normally confined to its loss. However, its byproducts are rarely discussed. In this study, an aged acrolein solution has been found to contain byproduct aldehydes, including the major soluble 5,6-dihydro-2H-pyran-3-carboxaldehyde. Despite acrolein's facile hydrolysis degradation, this byproduct is surprisingly stable in aqueous media for at least 25 years at ambient temperatures. The presence of this byproduct has been established by 1H and 13C NMR, using DEPT, COSY, and HMBC, and UV spectroscopy at λmax 229 nm in natural water systems.

The Journal of …, 1985

... Basic Chemical Research Section, Air Force Rocket Propulsion Laboratory (AFSC), Edwards AFB, ... more ... Basic Chemical Research Section, Air Force Rocket Propulsion Laboratory (AFSC), Edwards AFB, California 93523 Gene E. Heasley Department of Chemistry, Bethany Nazarene College,Bethany, Oklahoma 73008 Received November 2, 1984 ...

Results in Chemistry

Abstract Line-broadening by NMR is an easy and fast method to detect radical intermediates in sol... more Abstract Line-broadening by NMR is an easy and fast method to detect radical intermediates in solution. Chlorosulfonyl isocyanate reacts with electron-rich alkenes via a Single Electron Transfer pathway to give 1,4-diradical intermediates. The Triplet 1,4-diradical can change to the Singlet species at lower temperatures. Less reactive alkenes proceed via a concerted pathway.

ChemInform, 1997

Addition Reactions of Alkenes with Electronegatively Substituted Alcohols in the Presence of Xeno... more Addition Reactions of Alkenes with Electronegatively Substituted Alcohols in the Presence of Xenon Difluoride.-A variety of fluoro-, alkoxy-and alkoxyfluoro-substituted products of addition of alkoxyxenonfluoride intermediates to the model alkenes norbornene, 2-methylpent-1-ene and hex-1-ene are formed depending on the conditions. Selectivity between the various reaction paths is observed to be a sensitive function of especially solvent, temp., and catalyst. The regio-and stereochemistry of the products of norbornene substitution reveals insight into the mechanistic pathways occurring in such electrophilic additions.

The Journal of Organic Chemistry, Jun 1, 2003

Ionic reactions of terminal alkenes with chlorine (Cl(2)), bromine (Br(2)), and iodine monochlori... more Ionic reactions of terminal alkenes with chlorine (Cl(2)), bromine (Br(2)), and iodine monochloride (ICl) are sensitive to the alkyl substituents, and the positions and number of vinyl fluorine atoms. These perturbations influence the symmetry of the halonium ion intermediates, which can be determined by the distribution of the Markovnikov to anti-Markovnikov products. A vinyl fluorine on the number-2 carbon favors an unsymmetrical intermediate with greater charge on the number-2 carbon unless the alkyl group is electron withdrawing. A vinyl fluorine on the terminal number-1 carbon favors positive charge development on that carbon unless a resonance stabilizing group is on the number-2 carbon. The symmetry of halonium ions with vinyl fluorines on both carbons-1 and -2 depends primarily on the characteristics of the alkyl substituent. Intermediates range from open-ions with the positive charge on carbon-2, to various bridged species, to open-ions on the terminal carbon.

... 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dale Shellhamer, David Gleason, Sean... more ... 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dale Shellhamer, David Gleason, Sean Rodriguez, & Victor Heasley (Point Loma Nazarene 5d. PROJECT NUMBER ... Dale F. Shellhamer*, David C. Gleason, Sean J. Rodriguez, Victor L. Heasley ...

The Journal of Organic Chemistry, 2013

Chlorosulfonyl isocyanate (CSI) is reported to react with hydrocarbon alkenes by a stepwise dipol... more Chlorosulfonyl isocyanate (CSI) is reported to react with hydrocarbon alkenes by a stepwise dipolar pathway to give N-chlorosulfonyl-β-lactams that are readily reduced to β-lactams. Substitution of a vinyl hydrogen for a vinyl fluorine changes the dynamics for reaction with CSI so that a concerted pathway is favored. Rate constants were measured for reactions of CSI with monofluoroalkenes and some hydrocarbon alkenes. Activation parameters for two hydrocarbon alkenes and two monofluoroalkenes support this change in mechanism. A plot generated from the natural log of rate constants vs ionization potentials (IP) indicates that fluoroalkenes with IP values >8.9 eV react by a concerted process. Electron-rich monofluoroalkenes with IP values <8.5 eV were found to react by a single-electron transfer (SET) pathway. Hydrocarbon alkenes were also found to react by this dipolar stepwise SET intermediate rather than the previously accepted stepwise dipolar pathway. Data support a pre-equilibrium complex on the reaction pathway just before the rate-determining step of the concerted pathway and a SET intermediate for the stepwise reactions. When the reactions are carried out at lower temperatures, the equilibrium shifts toward the complex or SET intermediate enhancing the synthetic utility of these reactions. Kinetic data also support formation of a planar transition state rather than the orthogonal geometry as reported for ketene [2 + 2] cycloadditions.

Results in Chemistry, 2020

Paper is free on-Line at: https://doi.org/10.1016/j.rechem.2019.100015

The Journal of Organic Chemistry, 1999

Interhalogen fluorides (XF; X ) I, Br, or Cl) generated from xenon difluoride (XeF 2 ) or triethy... more Interhalogen fluorides (XF; X ) I, Br, or Cl) generated from xenon difluoride (XeF 2 ) or triethylamine trihydrofluoride (TREAT HF) with iodine (I 2 ), N-halosuccinimides (NXS; X ) I, Br, or Cl), or alkylhypohalites (ROX; R ) CH 3 or t-Bu, X ) Br or Cl) with alkenes and aromatics are reported. A comparison of the above reactions with other methods reported in the literature to generate interhalogen fluorides is made. Interhalogens generated from direct action of elemental fluorine (F 2 ) or XF 3 (X ) I, Br, or Cl) with chlorine (Cl 2 ), bromine (Br 2 ), or iodine (I 2 ) give a species that can react with electron-deficient alkenes or aromatics. These reagents are too reactive for electronrich substrates. Interhalogen fluorides from reagents like NXS or ROX with XeF 2 or amine HF are much less reactive and give good yields with electron-rich akenes or aromatics.

Iodine monofluoride, generated from XeF 2 and I 2 or NIS, reacts with alkenes to furnish iodofluo... more Iodine monofluoride, generated from XeF 2 and I 2 or NIS, reacts with alkenes to furnish iodofluorinated products [cf. (II), (IV), (V)] in good yields. The reaction of aromatics with XeF 2 and I 2 or NIS proceeds as electrophilic aromatic iodination [→ (VII), (IX)]. Iodine monofluoride (IF), generated from XeF 2 proves to be less reactive than IF generated from I 2 and fluorine gas. -(SHELLHAMER, D. F.; JONES, B. C.; PETTUS, B. J.; PETTUS, T. L.; STRINGER, J. M.; HEASLEY, V. L.; J.

Journal of Fluorine Chemistry, 1998

Reaction of xenon difluoride (XeF2) and iodine (I2) or N-iodosuccinimide (NIS) with alkenes gives... more Reaction of xenon difluoride (XeF2) and iodine (I2) or N-iodosuccinimide (NIS) with alkenes gives iodofluoro products in good yields. Aromatics react with XeF2 and I2 or NIS to undergo electrophilic aromatic iodination. Iodine monofluoride (IF) generated from XeF2 is less reactive than IF generated from I2 and fluorine gas. This difference in reactivity suggests that the interhalogen IF is delivered

ChemInform, 1995

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.