Simple high yield synthesis of methanol-18O and ethanol-18O

Sawyer, Charles B.

doi:10.1021/jo00798a070

Cited by 24 publications

(13 citation statements)

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“…A number of 18 O-labelled phenolic compounds were prepared [75] by heating a mixture of phenol with H 2 18 O in a sealed tube at 180°C. A related synthetic method [76], involves the substitution of a leaving group with 18 OH À followed by subsequent formation of a carbonyl derivative:…”

Section: Nucleophilic Substitution Reactionsmentioning

confidence: 99%

Oxygen-17 NMR spectroscopy: Basic principles and applications (Part I)

Gerothanassis

2010

Progress in Nuclear Magnetic Resonance Spectroscopy

126

107

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Section: Nucleophilic Substitution Reactionsmentioning

confidence: 99%

Oxygen-17 NMR spectroscopy: Basic principles and applications (Part I)

Gerothanassis

2010

Progress in Nuclear Magnetic Resonance Spectroscopy

126

107

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“…perhaps, the oxygen atom atsulfuric acid solutions and perchloric acid solutions were tached to the methyl group, that is, the oxygen derived from the prepared and standardized as previously described (8,9), methanol. The I8O content in this oxygen was calculated from ['80]methanol (12.3% excess lBO) was prepared from H 2 1 8 0 the (Miles Research) using the procedure of Sawyer (10).…”

Section: Methodsmentioning

confidence: 99%

Oxygen exchange in methanol in acid solutions. Transition state activity coefficients

McClelland¹

1980

Can. J. Chem.

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Can. J. Chem. 58,393 (1980) Rate constants for oxygen exchange of methanol in sulfuric acid and perchloric acid solutions are reported, along with activity coefficients of methanol in sulfuric acid. Transition state activity coefficients Cf,*) for methanol exchange and tert-butanol exchange have been calculated. Values off;* for the latter behave very similarly to those for tert-butyl acetate hydrolysis, consistent with a carbonium ion-like transition state. Values for methanol exchange show considerably more salting-out. consistent with an oxonium ion-like transition state. A significant difference with the A,J hydrolyses of esters and amides is noted. For the latter the transition state is salted-out relative to its protonated precursor, whereas for methanol exchange, there is little difference between the activity coefficient of the protonated alcohol and the transition state, with the latter actually being somewhat salted-in. It is pointed out that the transition state activity coefficient approach can be rigorously applied even in the absence of protonation data. We report here rate constants for the oxygen 67.2"C. After an appropriate time interval the sealed tube was exchange reaction of methanol in aqueous sulfuric removed and immersed in an ice bath to quench the exchange. In acid and perchloric acid solutions. ~l~~h~l oxygen the case of concentrated acids, a small quantity of water was also added. The solution was transferred to a small distillation exchange reactions have been studied in the past apparatus. which was evacuated to 0.05 Torr. Volatile compo-(I), although no kinetic data appear to have been nents were collected in a liquid nitrogen trap. until approxireported for methanol. With the exception of teyt-mately 1-2 g of material had accumulated. Pyridine (50 mL) was butanol oxygen exchange, there also appears (1) to added, followed by p-nitrobenzoyl chloride (20&). This was stirred at 50-60°C for 10 min. at which point 5 mL of water was have been no kinetic study Over a range of acidity added to react with any excess acid chloride. After an additional sufficiently great to rigorously test the applicability 10min stirring, the mixture was evaporated on a rotary of the various treatments now available for acid-evaporator. Ether (250 mL) and water were added, and the ether catalyzed (2-7). We in particular wished layer was washed with dilute aqueous hydrochloric acid, and lo test a new approach, the transition state activity three times with saturated sodium carbonate. Magnesium sulfate was added, and after filtration, the ether removed on a coefficient method ( 7 -On different types of reac-rotary evaporator. The remaining pale yellow solid was recrystion of known mechanism. For methanol exchange, tallized from chloroform -petroleum ether. Based on its nmr there can be little mechanistic uncertainty; it is spectrum this product is pure methyl p-nitrobenzoate, containdifficult to visualize a mechanism other than that ing less than 5%~-nitrobenzoic acid. Between 20 and 50% of the methanol orig...

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“…Labeled alcohols can be prepared by nucleophilic substitution (S N 2) of alkyl halides with labeled sodium hydroxide, formed via the reaction of labeled water with sodium metal or with sodium methoxide (Scheme a and b), and, mainly, by the reduction of labeled aldehydes, ketones, or esters with lithium aluminium hydride or sodium borohydride …”

Section: Synthetic Challengesmentioning

confidence: 99%