--- NOTES

T H E SYNTHESIS O F ETHANOLAMINE-1-C"

BY D. E . DOUGLAS AND ANNA ~ ~ I A R Y BURDITT

Pilgeram et al. (4) have reported a synthesis of uniformly labelled ethanol- amine-C14 from barium carbonate-C14 via acetylene and ethylene oxide, yielding di- and tri-ethanolamine as by-products.

We have synthesized ethanolamine-1-C1"rom radiocyanide through the formation of (C1"-cyano)methyl benzoate (1, 3) and its subsequent reduction with lithium aluminum hydride to ethanolamine in 30y0 over-all yield. This method involves only two stages and yields solely primary anline. The re- actions are as follows:

H?O+HCHO+NaC14N $ HOCH?C14S+NaOH

I EXPERIMENTAL

I (CIA-Cyano)methyl benzoate was prepared by the method of Aloy and I

Rabaut (I) on a semimicro scale as follows: T o 0.154 gm. (2.9 mM.) of sodium

I cyanide-C14 (3.28 X lo7 counts/min. total activity) in 0.5 ml. of water cooled

I in an ice-bath and stirred with a magnetic stirrer was added 0.24 ml. of 37% I forinalin (2.7 mlM. of formaldehyde). After one hour, 0.30 ml. (2.6 mM.) of

benzoyl chloride was added, and stirring a t O°C. continued three hours longer. After the addition of 3 ml. of 5% sodium bicarbonate, the reaction misture was extracted continuously with ether for two to three hours. The ether extract was dried thoroughly, first over calcium chloride, then over Drierite.

The cyanomethyl benzoate was reduced without isolation by the gradual addition of the dried ether solution to 3.5 ml. of an ethereal solution of lithium aluminum hydride (approximately 2.6 mM. per ml.). T h e complex was decom- posed by stirring with 30 ml. of water, added slowly, the ether was removed by evaporation, and the aqueous phase was saturated with carbon dioxide. The aluminum hydroxide was centrifuged off and washed thoroughly with several portions of hot water. T h e supernatant and washings were combined, 1 ml. of ethylene glycol monobutyl ether (2) and 5 ml. of 0.5 N sodium hy- droxide added, and the ethanolamine and water removed by lyophilization and condensed into a trap cooled with dry ice - isopropyl alcohol. The residue remaining was talten up in water, 1 ml. of ethylene glycol monobutyl ether added, and lyophilization repeated. This process was carried out four times altogether. The ethanolamine was recovered as hydrochloride by evaporation

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1184 C A S A D I A S JOURNAL O F CHEMISTRY. VOL. 33

of the combined condensates from the cold trap with excess hydrochloric acid, and the salt recrystallizecl from isopropyl alcohol - ether. Yield: 0.0946 gm. (30.9y0, based on sodiuin cyanide). The material was recrystallized for activity and melting point determinations. Specific activity: 132,000 counts per min. per mgin. Melting point: 79.8-82' C. Mixed melting point with authentic ethanolamine hydrochloride : 79.8-83' C.

Thirty-seven per cent of the initially added racliocyanide activity was found in the aqueous phase after ether extraction of the cyanomethyl benzoate.

To check the radiopurity, ethanolamine hydrochloride prepared by the above procedure was chromatographed on paper, with water-saturated phenol as the developing solvent. Radioautography indicated that the material was essentially free from radioactive contaminants. The Rf was 0.76.

1. .%LOT, J. and RABAUT, C. Bull. soc. chin]. France, (4) 13: 457. 1913. 2 HORSLEY, L. H. Bnnl . Chcm. 21: 838. 194'3. 3. MOWRY, D. T. J. Am. Chem. Soc. 66: 371. 1944. 4. PILGERAM, L. O., GAL, E. &I., SASSENRATH, E. N., and GREBSBERG, D. hI. J. Biol. Chem.

204: 367. 1953.

RECEIVED D E C E ~ ~ B E R 15, 195.1. DIVISION or; ATOMIC CHEBIISTRY, THE MOSTREAL GENERAL HOSI'ITAL, RESEARCH INSTITUTE, MONTREIL, P.Q.

A SELF PUMPING DROPPING MERCURY ELECTRODE FOR USE WITH STIRRED SOLUTIONS1

The theory of polarography assuines the formation of a polarized layer around one electrode in an electrolysis cell. If through agitation of the solution this layer is dist~irbed the current passing through the cell is no loilger diffusion dependent and the Illcovic equation does not apply. Uiilson and Smith (12) studied the effect of increasing flow rate of solution on the dropping mercury electrode (DME) and found first of all a deviation from diffusion coiltrolled current and finally a complete disruption of the regular drop formation. By employing a slolv rate of flo~l7 in a horizontal direction they mere able to monitor continuousI~7 sulphur dioxide in industrial solutions by a polarographic method (13). This principle has been used by a number of worliers (1, 11) while others have employed baffles (4, 5, 6, 7, 14) and some have even aban- doned the ordinary DAME in favor of the vibrating DME (2), or solid electrodes (3, 9, 10).

This paper describes a cell in which the DllIE is situated in a side arin and the solution is circulated past the electrode by the pumping action of the detached drops descending through a capillary. Basically the cell consists of a Lingane-Laitinen H cell (8) to xx~hicl~ a side arm has been attached

IContribzition No. 45, Sciefzce Service Laboratory, L o ~ t d o n , Ontario.

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