cis-Cyclohexano-9-crown-3 ether. Solid state and low-temperature solution stereochemistry as determined by X-ray crystallography and nuclear magnetic resonance spectroscopy

Abstract

The X-ray crystal structure of the title material has been determined at −130 °C. Low-temperature 1H1H COSY, 13C1H HETCOR, and DEPT 13C NMR spectra have been recorded, which permit unambiguous assignments of all carbon resonances when ring inversion is slow on the NMR timescale. The limiting low-temperature solution phase 13C spectrum has many common features with the solid phase 13C CPMAS spectrum recorded at 300 K. Spectra for the 7,10-tetra-deuterio derivative have also been obtained and substituent influences on 13C shieldings are discussed in detail.

Synthesis of cis-p-dioxano-12-crown-4 and X-ray crystallography of the (1:1) complex with lithium thiocyanate

“…This behaviour is anticipated to be of importance in the design of Li + selective complexing agents. Investigation into the preferred conformation of 1 in solution at low temperature (15,19) is in progress. In this regard the C s conformation of 12C4, which contains a plane of symmetry, is a likely candidate (8,(10)(11)(12)(13)14).…”

Electronic effects on crown ether conformation. X-ray crystal structure and 13C NMR study in solution and the solid phase of 4-nitrobenzo-9-crown-3 ether

“…The synthesis of benzo-9-crown-3-d, has been reported previously (7). Nitration of this material to give 1 was carried out using the following procedure which is similar to that reported for the synthesis of dinitrodibenzo-18-crown-6 ether (8).…”

Synthesis of the perdeuterated cellulose solvents N‐methylmorpholine N‐oxide (NMMO‐d11) and N,N‐dimethylacetamide (DMAc‐d9)

“…to 1) of sulfuric acid. Larger amounts favored the formation of the bislactone [1,4]dioxane-2,5-dione. Dimethyl diglycolate (2) underwent H/D-exchange (499%) in CD 3 OD/CH 3 ONa.…”

“…Dimethyl diglycolate (2) underwent H/D-exchange (499%) in CD 3 OD/CH 3 ONa. The obtained tetradeutero-diglycolic acid dimethylester (3) was used without further purification in the subsequent reduction (LiAlD 4 in THF), 1 providing diethylene glycol-d 8 (4). During addition of the reducing reagent, the reaction temperature must not exceed À101C, whereas subsequent heating of the mixture is crucial to ensure a complete reaction at 'both sides' of the diglycolate.…”