1316
H. It. NACEA N D Ii. F. KING
Vol. 5
A Study of the Reaction of the AscorbicDehydroascorbic Acid System and Related Model Compounds with Amphetamine HAROLD It. NACEand KENKETH h'. KING* Vetcalf Chenizcal Laboratorzes, B r o w n I-nzvvsity, Providence 12, Rhode Island
Received ,May 14, 1962 On the basis of a report' that ascorbic-dehydroascorbic acid %as capable of deaminating amphetamine, the reaction has been studied zn vztro using model compounds analogous to ascorbic acid and dehydroascorbic acid %7ith b e n d and biacetyl, mono-Schiff base condensation products were obtained which did not undergo isomerization and hydrolysis to produce ammonia and benzyl methyl ketone. Benzoin and acetoin reacted with amphetamine t o g i w rearranged a-N-alk) lamino ketones. In buffered aqueous solution, contrary to thP previous report, no evidence was obtained for the formation of animonia or benzyl iiiethvl ketone from amphetamine and the ascorbic acid-dehydroascorbic acid system.
Some years ago, Beyer' reported that the asc~orhic--dchydro acid system was capable of performing the non-enzymatic8 des of amphetamine and related sympathomimetic bases (Fig. 1). hoth 112 oivo and in uztro. This report led l i b to ipcculatc oil poxbiblc chemical mechanisms for these transformatioiib, a i d cIspcriments t o cstablish one of these, involving tautomerism of :i Schiff ha,e, resultctl in the work reported here. dnalogoui mechanisms have 1)ecii propoicd f o r t ti(> deamination of certain amino acidb with the prudwtion c u h n dioxide, and the corresponding :Lldehydei.? 1)icwI)oiiyl wmpounds of the type -CO(CH=CH),COal-o \\ere found to deaminate a-amino acidsd and on this ba a general mechanism I\ as proposed3 for the Strecker degradation* of a-aminoarid5 hy carbonyl compounds. This mechanism involved formation of ;I Schiff base which then was decarboxylated arid isomerized to give> ;L new- Schiff base which on hydrolysis gaw the rarbonyl compound as shown in Fig. 2 . Tautomerism of Schiff bases was :ilso ohserved i l l
Xovernber, 1962
ASCORBIC-DEHYDROASCORBIC ACIDAND AMPHETAMINE1317
+
--tCeHSCHzCOCH? NH3 Fig. 1.-Beyer’s scheme for the deamination of amphetarnine by dehydromcorbic acid.
‘co 1
/co
\
+ H,NCHRCO,H+ \ /
C=NCHRCO,H + I
co /l? __
I
C=NC : 0 I H -
co
Fig. 2.-Deamination
\
\
C-N=CHR
J-6;:@ / **
C-NHz
+
&-OH
+ HCHO
/
of amino acids by a-diketones.
strongly basic solution for compounds of the type aryl’ -CHRS= C(ar~l~)~.~ This type of reaction appeared attractive as an explanation for Beyer’s deamination scheme and, accordingly, experiments were undertaken to isolate Schiff base intermediates from amphetamine and the ascorbic-dehydroascorbic acid system, as well as simpler model compounds. Evidence that such a mechanism was involved would indicate an important role for vitamin C not only in the metabolism of sympathomimetic amines but possibly of amines in general in the animal system. Also, chemical evidence for the mechanism would provide the basis for the synthesis of substances even more effective than vitamin C in controlling the metabolism of sympathomimetic amines. Since the initial experiments with either ascorbic acid or dehydroascorbic acid and amphetamine appeared to give complex mixtures, attention was turned to simpler model systems. Benzil and biacetyl were chosen as model a-diketones since both exhibited the same type of activity as dehydroascorbic acid in the Strecker degradation of cyamino acids.3 When benzil was heated with amphetamine (I) one molar equivalent of water was produced and benzilmono-@-phenylisopropyl)-imine (11,R = CeH5) was obtained in 59% yield. Biacetyl ( 5 ) C. K Ingold and C. L. Wilson, J . Chem Soc , 1493 (1933); 93 (19341, S. K . Hsii, C. K. Ingold, and C. L. Wilson, zbzd., 1778 (1935).
and amphetamine reacted to give :3-@-phenyhsopropylimiiio)butailone (11, R = CH,) in 33Yc yield. a proof of structure both azomethine compounds were reduced with lithium aluminum hydride to the corresponding amino alcohol- 111, u-hich were cahnrac.t,erized by their infrared spectra and elemental analy S o shift of the carbon-nitrogen douhlck hond took pluc*ein aqueous acid, but hydrolysis to the btarting diketone and amphetamine occurred and no benzyl methyl ketone c~)nldhe detwted. Khen t h c benzil asornethilie I1 (R = CsH,) nab rrwted uith either methanolic sodium methoxide or aqueous ethanolic - withdraTv:d through the extractor and the rc.mai1idt.r I)?, distillation at 100" under rcdiiccd .11. 3.39, 5.02, 6.25 and pressure. The product was a visrcius ycllow oil. A 6.71 /*. I t was taken up in 100 nil. of anhydroufi ethrr and (~sccsset,haiiolic h?-drogen chloride was added dropt&c. -After cooling tlie mixture overnight t i t 0 Several recrystallizations the hydrochloride was collected to givcx 11.5 g. iGXS;). from ethanol did not, give a sharp melting product, indicating t,he presenro i i f diastereomers. The analytical samplc had m.p. 204-210' der., As,::"' 3.56. .i.SS, 6.21 and 6.67 p . (14) It. L. S h i n e r , It. C. Fusun. 311111 I). 1. C:artin. "Tho Systelriatic I d c n t i h c a t r u n uf 0 1 . gitnic Compounds," ,John \Tiley a n d rions. h e . , S e w \-lJl'k, N. Y . ,4th E d . . 1956. p. 219.
November, 1962
ASCORBIC-DEHYDROASCORBIC ACIDAND AMPHETAMIXE1323
Anal. Calcd. for C23H24ClKO: C, 75.50; H, 6.62; X, 3.83. Found: C, 75.48; H, 6.70; N, 4.30. 2-(N-p-Phenylisopropylamino)-1,2-diphenylethanol(111, R = CbHjj : (a) by Sodium Borohydride Reduction of a-(N-0-Pheny1isopropylamino)-desoxybenzoin (IV, R = C6HS).--To a stirred solution of 9.2 g. (0.025 mole) of a-(N-pphenylisopropy1amino)-desoxybenzoinhydrochloride in 100 ml. of methanol was added in portions 5 g. of sodium borohydride. The product precipitated during the exothermic reduction and the mixture was stirred for 3 hr. after the addition was complete and then was poured into an ice and water mixture. The collected product was dissolved in ether, the solution was dried over anhydrous magnesium sulfate, the ether was evaporated, and the residue was washed with ' 3 2.94, 3.22, 6.22 and 6.85 p , identical with hexane to yield 5.9 g. (717,), X ~ ~ x c2.76, the infrared spectrum of the amino alcohol I11 ( R = C6H5)from the reduction of benzil mono-(p-phenylisopropyl)-imine. The analytical sample was prepared by recrystallization from ether and had m.p. 145-146.5'. 4nuZ. Calcd. for C23H?o?;O: C, 83.34; H, 7.60; N, 4.23. Found: C, 83.34; H, 7.83; S , 4.28. (b) By Reaction of Desyl Chloride with Amphetamine.-A solution of 4.5 g. (0.02 mole) of desyl chloride and 5.4 g. (0.04 mole) of amphetamine in 50 ml. of ethanol was heated on a steam bath for 15 min. and then allowed to stand at room tempprature for 37 hr. The reaction mixture was poured into 100 ml. of water and this mixture was extracted with two 25-ml. portions of ether. The ether extract was then extracted with four 25-1111. portions of 15y0 hydrochloric acid and this extract on standing gave 1.0 g. of white solid, which was recrystallized from ethanol and then had m.p. 218-230" dec., infrared spectrum identical with that of a-(N-p-pheny1isopropylamino)-desoxybenzoinfrom the condensation of benzoin and amphetamine. This product (1.0 g.) was reduced with sodium borohydride as described above for Is' ( R = CsHj). The reduction product, after two recrystallizations from ether, had m.p. 141-147", not depressed when mixed with 2-(N-p-phenylisopropylamino)-1,2-diphenylethanolprepared above. 3-(p-Phenylisopropylimino)-butanone (11, R = CH3).-To a solution of 9.10 g. (0.015 mole) of biacetyl in 25 ml. of anhydrous ether was added a solution of 13.5 g. (0.10 mole) of amphetamine in 15 ml. of anhydrous ether. After the exothermic reaction had subsided the cloudy solution vvas boiled under reflux for 30 min. and then the water formed was removed by means of a separatory funnel. The ether soliltion was dried over anhydrous magnesium sulfate overnight under nitrogen and then the solvent was removed under reduced pressure to give 18.4 g. of a viscous reddish-brown oii. This was distilled through an 18 cm. Vigreux column and three fractions were collected: frac. I, 1.4g., b.p. up to 98" (0.40 mm.): frac. 11,5.0 g., b.p. 98-100" ((0.40 mm.); frac. 111,2.0 g., b.p. 100-103° (0.40 mm.). There was extensive decomposition during the distillation and a better yield was obtained by using a flame rather than an oil bath. Fractions I and I11 were combined and redistilled to give 1.6 g. of liquid b.p. 92-96' (0.30 mm.), which was combined with fraction I1 to give a total of 6.6 g. (32%) of 3-(p-phenylisopropylimino)-butanone,nZ5D 1.5095, 3.29, 5.88, 6.07, 6.21, and 6.71 p . An analytical sample was prepared by redistillation through an 18 cm. Vigreux column and had b.p. 95-96' (0.30 mm.). Anal. Calcd. for Cl3H17YO: C, 76.81; H, 8.43; N, 6.89. Found: C, 77.10; H, 8.50; X, 6.96.
1324
H. 12. ?LI'A(:E
AND
I
0 309 0 429 0 731 0 i84
0 -100 0 1i2 0 072 4 8 00 0 00 I L 1 070 Total amine base calculated as 10 times the value for a 50 nil. :ili(~u(itof the 500 ml. reaction solution.
:1
1
->
The insoluble part did not melt when heated to 400". Evaporation of the ethanol solution gave a dark resinous material which W:IS not, the 2.l-tlinit~rophen~lli~drazone of benzyl met,hgl ketone. Reactions of Dehydroascorbic Acid with Amphetamine (a) in 2-Propanol.To a solution of 1.0 g. (0.0048 mole) of dehydroascorbic acid-methanol complex'6 in 10 ml. of anhydroiis 2-propanol was added a solution of 1.3 g. (0.0096 molt.') of amphetamine in 5 ml. of 2-propanol. After 12 hr. at room temperature the dark brown solution T T ~ Sdiluted ll-ith 50 ml. of anhydrous ether. The light-t.an precipitat,e was collected hy decantatmion,washed with another 50 ml. of et,her. and dried over c*alciuni chloride. The infrared spectrum way identical with t'hat of amphetaminr ascorbate. The ether solut'ion yielded a dark syrupy residue on evaporation of thc ethcr. The react,ion was also run using :I 1 : 1 ratio of :mine and methanol coml~lesin 0.0024 mole quantities in I 0 nil. of anhydrous %-propanol for 4 days at 0". The yellow precipitate was dried ovcr calcium chloride under reduced prcwure and had an infrared spectrum identical with that, of :tmph~t~aniinc~ ascorhttc. (b) In Anhydrous Ethanol.-A solution of 0.50 g. (0.0024 niolej of dehydroascorbic acid-methanol complex and 0.34 g. (0.0024 mole) of amphetamine in 10 ml. of anhydrous et'hanol \viis kept at, 0' for 24 hr. Thr solvent \vas then evaporated a t room tempprat,ure under rediicrd pressure arid the, residue w i s washed with tmhree25 ml. portions of anhytlrous ether and dried ovcr calcium chloride under reduced presure i o give a ~-eIl(ixpcr\~-dcrwhose infrared spectrum was identical with that of amphetaminra The experiment, was repeated but with 2.06 g. (U.01 niole I of ciehydroascorhic acid and 2 . ; g. (0.02 mole) of amphetmiinc in 20 nil. of anhydrous meth:rnol. After removal of the solvent, 80 ml. of 2 Jf sulfuric acid was added to the syrupy residue and t h e niixt,ure was continuously extracted with et,her for 24 hr. The ether ext,r:irt was t.v:ip(ir:ited and 25 nil. of 95yoethanol was added to the gumin>residue. h gummy strlid formed which was dissolved in boiling ethanol and treated with 2,1-dinitrophenylliydra~ine. No hydrazone could be isolated. The (lti) Dehydroascorbic acid was used in all expriiiients i n the forin of its mt.tIiano1 complex because of t h e greater solubility. T h e material \\-as obtained from Nutritional Biochemicals Corporation, a n d its preparation a n d properties are described by B. Peclierer. J . Am. Chern. S i x . 73,3827 (1951). The coinldex givps all of the normal reactions of dehydroascorbic arid.
Novrmher, 1963
ACETYLHYDRAZINE AS A
hfET.4BOLIC IKTERMEDIATE
1.727
ethanol filtrate was treated with 2,4-dinitrophenylhydrazineand a hydrazone was obtained. It was recrystallized from acetone and had m.p. 306-307" dec. Reported for benzyl methyl ketone 2,4-dinitrophenylhydrazone, m.p. 1560.17 (c) In Aqueous Buffered Solution.-A solution of 2.0 g. (0.012 mole) of amphetamine hydrochloride in 500 ml. of 0.0625 M potassium dihydrogen phosphate was adjusted to pH 7.0 by the addition of potassium hydroxide solution, 1.0 g. (0.0048 mole) of dehydroascorbir acid-methanol complex in 20 ml. of buffer was added, and the pH was again brought up to 7.0. The solution was then kept a t room temperature for 36 hr., during which time it turned dark amber. Then 25 ml. of concd. sulfuric acid was added and the solution was distilled into a saturated aqueous hydrochloric acid solution of 2,4-dinitrophenglhydrazine. No hydrazone dzrivative could be isolated. (17) S. M. McElvain, "The Characterization of Organic Compounds," The Macmillan Co., New York, N. T., 1953, p. 236.
Acetylhydrazine as an Intermediate i n the Metabolism of Aroylhydrazines',2 LESI'OXB. TURSBULL, A L L ~s. S Y.4RD, and HERBERT MCKENXIS, *JR. DppaTtmpnt of Phnmiacoloqy, Medzcal College of Virginia, Richmond, Vu.
Received May 3, 1969 The oral administration of benzhydrazide or 1-acetyl-2-benzoylhydrazine leads in the rabbit to the urinary excretion of 1,2-diacetylhydrazine. l-Acetyl-C14-2benzoylhydrazine, prepared from benzhydrazide and acetic anhydride-l-CI4, in the rat similarly led to the urinary excretion of 1,2-diacetylhydrazine, which had a specific activity of approximately SOYo of the administered compound. 1,2-Diacetylhydrazine-C14itself was converted only slightly (0.1-0.3%) to respiratory carbon dioxide. Acetylhydrazine in the dog was converted in part t o hydrazine. These data are consistent with previous experiments on isoniazid and its metabolite acetylisoniazid. They suggest that one of the routes for the metabolism of certain aroylhydrazines in man, the rabbit, and the rat is: aroylhydrazine -* 1-acetyl-2-aroylhydrazine -+ acetylhydrazine + 1,2-diacetylhydrazine.
Previous s t ~ d i e swere ~ , ~ designed t o test a hypothetical routes in which the metabolism of isonicotinic acid hydrazide leads t o the (1) Preeented in part a t the meeting of the American Society for Pharmacology and Experimental Therapeutics, April 14-18, 1958, Philadelphia, Penna. (2) .4ided b y a research grant (RG-5337)from the National Institutes of Health, U. S. Public Health Service. (3) A. S.Yard a n d H. McKennis, Jr.. Federation P r o c . , 17, 421 (1958). (4) .4. S.Y a r d a n d €1. McKennis, Jr., J. N e d . Pharm. Chem., 6, 196 (1962). (5) H.McKennis, Jr., 4 . 8. Yard, J. H. Weatherby, a n d J. A. Hagy, J . Pharmacol. E r p l l . Therap.. 1116, 109 (1959).
