Abstract
The antimicrobial compounds 1-chloro-3,5,5-trimethylhydantoin and 3-chloro-1,5,5-trimethylhydantoin (1 and 2, respectively) have been synthesized and examined via a joint experimental and computational study. The measured rate of loss of oxidative chlorine in the absence and presence of exposure to UVA irradiation determined 2 to be less stable than 1. An interesting migration reaction was observed during UVA irradiation that featured the production of chlorine rearrangement and dechlorinated compounds. Two novel hydrogen atom transfer reaction (HATR) mechanisms have been proposed: (1) an intramolecular process in which a hydrogen atom undergoes a series of sigmatropic shifts, and (2) an intermolecular pathway in which a radical abstracts a hydrogen atom from a neighboring molecule. Density functional theory (DFT) calculations at the UB3LYP/6-311G++(2d,p) theory level have been employed to elucidate the preferred reaction pathway. Both proposed HATR mechanisms predicted 2 to possess a lower free energy of activation, ΔG ‡, relative to 1 in accordance with the experimental stability measurements. However, the intermolecular route had an overall lower absolute ΔG ‡ and was more consistent with measured product ratios in solution. The intermolecular reaction pathway, unlike the intramolecular route, also predicted the lack of formation of a migration product featuring a Cl covalently bonded to a methylene group at the 5-position of the hydantoin moiety, which was verified by NMR experiments.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7245-7252 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry A |
| Volume | 116 |
| Issue number | 26 |
| DOIs | |
| State | Published - Jul 5 2012 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
Cite this
Inter- and intramolecular mechanisms for chlorine rearrangements in trimethyl-substituted N-chlorohydantoins. / McCann, Billy W.; Song, Hao; Kocer, Hasan B.; Cerkez, Idris; Acevedo, Orlando; Worley, S. D.
In: Journal of Physical Chemistry A, Vol. 116, No. 26, 05.07.2012, p. 7245-7252.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Inter- and intramolecular mechanisms for chlorine rearrangements in trimethyl-substituted N-chlorohydantoins
AU - McCann, Billy W.
AU - Song, Hao
AU - Kocer, Hasan B.
AU - Cerkez, Idris
AU - Acevedo, Orlando
AU - Worley, S. D.
PY - 2012/7/5
Y1 - 2012/7/5
N2 - The antimicrobial compounds 1-chloro-3,5,5-trimethylhydantoin and 3-chloro-1,5,5-trimethylhydantoin (1 and 2, respectively) have been synthesized and examined via a joint experimental and computational study. The measured rate of loss of oxidative chlorine in the absence and presence of exposure to UVA irradiation determined 2 to be less stable than 1. An interesting migration reaction was observed during UVA irradiation that featured the production of chlorine rearrangement and dechlorinated compounds. Two novel hydrogen atom transfer reaction (HATR) mechanisms have been proposed: (1) an intramolecular process in which a hydrogen atom undergoes a series of sigmatropic shifts, and (2) an intermolecular pathway in which a radical abstracts a hydrogen atom from a neighboring molecule. Density functional theory (DFT) calculations at the UB3LYP/6-311G++(2d,p) theory level have been employed to elucidate the preferred reaction pathway. Both proposed HATR mechanisms predicted 2 to possess a lower free energy of activation, ΔG ‡, relative to 1 in accordance with the experimental stability measurements. However, the intermolecular route had an overall lower absolute ΔG ‡ and was more consistent with measured product ratios in solution. The intermolecular reaction pathway, unlike the intramolecular route, also predicted the lack of formation of a migration product featuring a Cl covalently bonded to a methylene group at the 5-position of the hydantoin moiety, which was verified by NMR experiments.
AB - The antimicrobial compounds 1-chloro-3,5,5-trimethylhydantoin and 3-chloro-1,5,5-trimethylhydantoin (1 and 2, respectively) have been synthesized and examined via a joint experimental and computational study. The measured rate of loss of oxidative chlorine in the absence and presence of exposure to UVA irradiation determined 2 to be less stable than 1. An interesting migration reaction was observed during UVA irradiation that featured the production of chlorine rearrangement and dechlorinated compounds. Two novel hydrogen atom transfer reaction (HATR) mechanisms have been proposed: (1) an intramolecular process in which a hydrogen atom undergoes a series of sigmatropic shifts, and (2) an intermolecular pathway in which a radical abstracts a hydrogen atom from a neighboring molecule. Density functional theory (DFT) calculations at the UB3LYP/6-311G++(2d,p) theory level have been employed to elucidate the preferred reaction pathway. Both proposed HATR mechanisms predicted 2 to possess a lower free energy of activation, ΔG ‡, relative to 1 in accordance with the experimental stability measurements. However, the intermolecular route had an overall lower absolute ΔG ‡ and was more consistent with measured product ratios in solution. The intermolecular reaction pathway, unlike the intramolecular route, also predicted the lack of formation of a migration product featuring a Cl covalently bonded to a methylene group at the 5-position of the hydantoin moiety, which was verified by NMR experiments.
UR - http://www.scopus.com/inward/record.url?scp=84863633042&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84863633042&partnerID=8YFLogxK
U2 - 10.1021/jp304610k
DO - 10.1021/jp304610k
M3 - Article
C2 - 22671993
AN - SCOPUS:84863633042
VL - 116
SP - 7245
EP - 7252
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
SN - 1089-5639
IS - 26
ER -