Ketones nuclear magnetic resonance

An unusual method for the preparation of syndiotactic polybutadiene was reported by The Goodyear Tire Rubber Co. (43) a preformed cobalt-type catalyst prepared under anhydrous conditions was found to polymerize 1,3-butadiene in an emulsion-type recipe to give syndiotactic polybutadienes of various melting points (120—190°C). These polymers were characterized by infrared spectroscopy and nuclear magnetic resonance (44—46). Both the Ube Industries catalyst mentioned previously and the Goodyear catalyst were further modified to control the molecular weight and melting point of syndio-polybutadiene by the addition of various modifiers such as alcohols, nitriles, aldehydes, ketones, ethers, and cyano compounds. 

Enamino ketones can protonate not only on nitrogen or carbon but also on oxygen to give 12,13, and 14, respectively. Enamino ketones form stable perchlorates, chlorides, bromides, and iodides, and examination of their infrared (21,22), ultraviolet (23), and nuclear magnetic resonance (24,25) spectra show these salts to be O protonated. The salts of 4-dialkylamino-... 

Ramirez, F., Madan, O.P., and Heller, S.R., A crystalline tetraalkoxyalkylphos-phorane from the reaction of trimethyl phosphite with an a,JS-unsaturated ketone. 3-Benzylidene-2,4-pentadienone. 31P and H nuclear magnetic resonance spectra, /. Am. Chem. Soc., 87, 731, 1965. 

Ethers of the 1,2-benzisothiazole 1,1-dioxides (35 R = Et, Me3Si) have been shown to form 1,2-benzothiazepines 12 (R = Et, Mc Si) when treated with 1-diethylamino-l-propyne 37 <1996T3339>. These ethers 12 may be hydrolyzed to the ketone 13 (see also Section 13.07.2.1), which in the solid state is in equilibrium with the enol 12 (R = H) on the basis of infrared (IR) evidence (Scheme 3). In solution (CDCI3), only the keto form 13 was detectable by H nuclear magnetic resonance (NMR). 

If the unknown, neutral, oxygen-containing compound does not give the class reactions for aldehydes, ketones, esters and anhydrides, it is probably either an alcohol or an ether. Alcohols are readily identified by the intense characteristic hydroxyl adsorption which occurs as a broad band in the infrared spectrum at 3600-3300 cm-1 (O—H str.). In the nuclear magnetic resonance spectrum, the adsorption by the proton in the hydroxyl group gives rise to a broad peak the chemical shift of which is rather variable the peak disappears on deuteration. 

Analysis with chiral nuclear magnetic resonance shift reagents revealed that the isotactic poly (1,4-ketone) products were formed with an average or overall degree of enantioselectivity that was >90%. Using the same catalyst, Jiang and Sen also described the first example of alternating co-polymerization between an internal alkene (2-butene) and carbon monoxide to form an isotactic, optically active poly(l,5-ketone). 

Acid hydrolysis of 5-amino-5-deoxy-l,2-0-isopropylidene-o -D-xy-lofuranose (15) might be expected to afiFord 5-amino-5-deoxy-D-xylose, but instead, at 70 , 3-pyridinol (21) is the main product. If the acid hydrolysis of compound 15 is conducted at room temperature, there is obtained, besides 3-pyridinol (21), the crystalline hydrochloride of l-amino-l,5-anhydro-l-deoxy-D-fhreo-pentulose hydrate (22). The crystalline hydrate exhibits no carbonyl band in its infrared and ultraviolet spectra. The water content cannot be removed without decomposition of the compound, and is, therefore, water of constitution. The nuclear magnetic resonance spectrum of 22 lacks the signal characteristic of an anomeric proton. The free ketone group is, however, detectable by the preparation of a (2,4-dinitrophenyl)-hydrazone. 

A nuclear magnetic resonance study ( H, Te) of these reaction mixtures established that ketonyl tellurium trichlorides and diketonyl tellurium dichlorides are present. The easily crystallized and less soluble compounds were isolated. Contrary to Morgan s claim, ethyl methyl ketone did react to give bis[2-oxo-l-butyl] tellurium dichloride albeit in very low yield. Alkyl ethyl ketones and tellurium tetrachloride produced very low yields of bis[3-oxo-2-alkyl] tellurium dichlorides. Cyclooctanone and tellurium tetrachloride in refluxing carbon tetrachloride gave bis[2-oxocyclooctyl tellurium dichloride (m.p, 174°) in 40% yield . 

Dave, V., Stothers, J. B., Warnhoff, E. W. Ring expansion of cyciic ketones the reiiabie determination of migration ratios for 3-keto steroids by carbon-13 nuclear magnetic resonance and the general implications thereof. Can. J. Chem. 1979, 57,1557-1568. 

Greenzaid, P., Z. Luz, and D. Samuel A Nuclear Magnetic Resonance Study of the Reversible Hydration of Aliphatic Aldehydes and Ketones. I. Oxygen-17 and Proton Spectra and Equilibrium Constants. J. Am. Chem. Soc. 89, 749 (1967). 

Anet FAL, Cheng AK, Krane. J (1973) Conformations and energy barriers in medium and large ring ketones. Evidence from C and H nuclear magnetic resonance. J. Am. Chem. Soc. 95 7877... 

Norrish type 1 photoreaction, 124 photocleavage of ketones, 124 Nuclear magnetic resonance (NMR), 182, 213-214... 

Many cellulose derivatives form lyotropic liquid crystals in suitable solvents and several thermotropic cellulose derivatives have been reported (1-3) Cellulosic liquid crystalline systems reported prior to early 1982 have been tabulated (1). Since then, some new substituted cellulosic derivatives which form thermotropic cholesteric phases have been prepared (4), and much effort has been devoted to investigating the previously-reported systems. Anisotropic solutions of cellulose acetate and triacetate in tri-fluoroacetic acid have attracted the attention of several groups. Chiroptical properties (5,6), refractive index (7), phase boundaries (8), nuclear magnetic resonance spectra (9,10) and differential scanning calorimetry (11,12) have been reported for this system. However, trifluoroacetic acid causes degradation of cellulosic polymers this calls into question some of the physical measurements on these mesophases, because time is required for the mesophase solutions to achieve their equilibrium order. Mixtures of trifluoroacetic acid with chlorinated solvents have been employed to minimize this problem (13), and anisotropic solutions of cellulose acetate and triacetate in other solvents have been examined (14,15). The mesophase formed by (hydroxypropyl)cellulose (HPC) in water (16) is stable and easy to handle, and has thus attracted further attention (10,11,17-19), as has the thermotropic mesophase of HPC (20). Detailed studies of mesophase formation and chain rigidity for HPC in dimethyl acetamide (21) and for the benzoic acid ester of HPC in acetone and benzene (22) have been published. Anisotropic solutions of methylol cellulose in dimethyl sulfoxide (23) and of cellulose in dimethyl acetamide/ LiCl (24) were reported. Cellulose tricarbanilate in methyl ethyl ketone forms a liquid crystalline solution (25) with optical properties which are quite distinct from those of previously reported cholesteric cellulosic mesophases (26). 

Nuclear magnetic resonance spectroscopy has been used to study self-ossociation in promethazine hydrochloride, in 2-butyl-3-benzofuranyl 4-[2-(diethylamino) ethoxy]-3,5-diiodo-phenyl ketone hydrochloride (SKF 33134A),40ond in d-propoxyphene hydrochloride. Florence has measured the properties of p-diethylaminoethyl diphenylpropylacetate hydrochloride (SKF 525-A) by light scattering, surface tension, and microelectrophoretic techniques. He suggests that caution should be exercised in the interpretation of enzyme inhibition results obtained with a compound of this type since it exhibits surface activity, and surfactants are known to exert an appreciable effect on certain enzyme systems. 

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