Kinetic and theoretical considerations in the hydrolysis of iminocarbonates

Jehoshua Katzhendler*, Amiram Goldblum, Israel Ringel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Analysis of the pH-rate profiles for the hydrolysis of 4-methyl-2-(N- phenylimino)-1,3-dioxolane (1) and 2-[N-(p-fluorophenyl)imino]-4-phenyl-1,3- dioxolane (2) together with product distribution of compounds (1)-(5) and pK values estimated for the various ionic forms T0, T+, T±, and T- of the tetrahedral intermediates, enables the determination of the reactivity of the tetrahedral intermediates along their reaction pathways. At pH <6, the only products formed are the amine and the carbonate (C-N fission) and at pH >6 C-O bond fission increases to form carbamates. The transition point corresponds to pK values of 9.2 and 8.5 for compounds (1) and (2), respectively. It is proposed that in acidic solution C-N bond fission proceeds via T+ ⇌ T+ → P while at a moderate pH this bond fission proceeds via a proton-switch mechanism T0 → T±. At pH > 11 the only product produced is the hydroxycarbamate (C-O fission) via its anionic intermediate T-. Mono- and gem-dimethyl substituted iminocarbonates T- undergo two modes of ring-opening. Employing MNDO/H calculations the relative stability (ΔHF) of the intermediates and their formed products was predicted and correlated with actual experimental product distribution.

Original languageAmerican English
Pages (from-to)1653-1660
Number of pages8
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number9
DOIs
StatePublished - 1988

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