Herein described is a strategy for promoting thermodynamically unfavorable [3,3] Cope rearrangements. 3,3-Dicyano-1,5-dienes that are resistant to the thermal rearrangement can be promoted under reductive conditions. The reduced Cope products are versatile, bifunctional building blocks.
Level anticrossings (LACs) are ubiquitous in quantum systems and have been exploited for spin-order transfer in hyperpolarized nuclear magnetic resonance spectroscopy. This paper examines the manifestations of adiabatic passage through a specific type of LAC found in homonuclear systems of chemically inequivalent coupled protons incorporating parahydrogen (pH 2 ). Adiabatic passage through such a LAC is shown to elicit translation of the pH 2 spin order. As an example, with prospective applications in biomedicine, proton spin polarizations of at least 19.8 ± 2.6% on the methylene protons and 68.7 ± 0.5% on the vinylic protons of selectively deuterated allyl pyruvate ester are demonstrated experimentally. After ultrasonic spray injection of a precursor solution containing propargyl pyruvate and a dissolved Rh catalyst into a chamber pressurized with 99% para-enriched H 2 , the products are collected and transported to a high magnetic field for NMR detection. The LAC-mediated hyperpolarization of the methylene protons is significant because of the stronger spin coupling to the pyruvate carbonyl 13 C, setting up an ideal initial condition for subsequent coherence transfer by selective INEPT. Furthermore, the selective deuteration of the propargyl side arm increases the efficiency and polarization level. LAC-mediated translation of parahydrogen spin order completes the first step toward a new and highly efficient route for the 13 C NMR signal enhancement of pyruvate via side-arm hydrogenation with parahydrogen.
Phytocannabinoids (and synthetic analogs thereof) are gaining significant attention as promising leads in modern medicine. Considering this, new directions for the design of phytocannabinoid‐inspired molecules is of immediate interest. In this regard, we have hypothesized that axially‐chiral‐cannabinols (ax‐CBNs), unnatural and unknown isomers of cannabinol (CBN) may be valuable scaffolds for cannabinoid‐inspired drug discovery. There are two main factors directing our interest to these scaffolds: (a) ax‐CBNs would have ground‐state three‐dimensionality; ligand‐receptor interactions can be more significant with complimentary 3D‐topology, and (b) ax‐CBNs at their core structure are biaryl molecules, generally attractive platforms for pharmaceutical development due to their ease of functionalization and stability. Herein we report a synthesis of ax‐CBNs, examine physical properties experimentally and computationally, and perform a comparative analysis of ax‐CBN and THC in mice behavioral studies.
Explored was the competitive ring-closing metathesis vs. ring-rearrangement metathesis of bicyclo[3.2.1]octenes prepared by a simple and convergent synthesis from bicyclic alkylidenemalono-nitriles and allylic electrophiles. It was uncovered that ring-closing metathesis...
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