4738
Vol. 82
COMMCSIC,ITIOSS TO TIIE EDITOR
Kinetic Procedure.-Solutions of the episulfide and triphenylphosphine of identical concentration were prepared and thermostated a t 40 + 0.1'. After thermal equilibrium had been reached the solutions were miscd. The progress of the reaction was followed by pipetting 1-ml. aliquots into a known excess of st:rn&rd iodille solutiol1 (ca. 0.01 N)and rapidly bnck-titrating the excess iodine \rith standard triphenylphosphine scilution (ce 0.01 N J . Both standard solutions used a mixture of 75',* benzene and 23';; ethanol as the solvent. Two aliquvts taken withiii the first
3 minutes were used to establish the initial concentratitrri . The second-order rate constants were calculated from the equati,,t, k = The data for a representative
(:
to) t.
run on cis-2-butene episulfide are compiled below. The solvent used was S,N-dimethylformamide. T h e iodine concentration was O.00935N and t h e iodine/triphenylphosPk'i11e titer Was 0.91. SEW RRUSSIVICK,S.J
COMMUNICATIONS T O T H E EDITOR POTENTIAL ANTIRADIATION DRUGS. I. SUGAR ETHYLENIMINES AND EPISULFIDES.'
OCH2
OCH?
Sir : Epoxides are among the most versatile intermediates in rare sugar synthesis2 In particular, those epoxides that are fused to sugar rings of either the pyranose or furanose form provide pathways for certain transformations that would otherwise be hindered or prevented by the very ~ of the secondary sulfonate low S N reactivity esters or secondary halides in sugar rings. The ethylenimines and episulfides that correspond to these fused epoxides ought to be equally interesting intermediates in sugar synthesis but have not been described previously. In work directed toward the synthesis of sugars containing a B-mercaptoethylamine moiety, methods that should have general utility have been developed for the preparation of these unique sugar derivatives containing both types of three-membered rings, and are the subject of this Communication. The 3-aminoaltroside I?with carbon disulfide and iodomethane in pyridine which contained triethylamine5 gave a quantitative yield of the crude crystalline dithiocarbamate 11, m.p.6 157-190" (Found: C, 52.2; H, 5.37; S, 17.2). Conventional sulfonylation in pyridine afforded 8070 of the crystalline rnesylate (111), m.p. 168-170" (Found: C, 46.0; H, 5.38; S, 20.7), which, when heated a t 60"for 4-5 minutes with 1.10 equivalents of sodium methoxide in methanol-2-methoxyethanol, gave 6.5% of the thioacylated ethylenimine IV, m.p. 198-212' (Found: C, 54.4; H, 3.42; S, 18.41. Compound IV showed no infrared C=N absorp-
SH
-1;
I
CH,S-C=S II,R=H 111,R = bls
t C,H,CH
SHE
I
t OCHZ
VIII,X=SH IX,X=S
t OCHz
scs VI, R = H 1'11, R = M S
tion near 6.2 p which would be expected for the isomeric thiazoline that would result from sulfur participation in the displacement.' The "complex neighboring group"8 participation, then, went by predominant, if not exclusive, nitrogen attack (1) This work was carried out under the joint auspices of the OAice in this instance to form a three-membered ring, r f t h e Surgeon General, Medical Research and Development Coma pathway to the isomeric and less-strained although mand, under Contract No. DA49-193-MD-268 and of t h e Cancer five-membered thiazoline would seem to have Chemotherapy National Service Center, A'ational Cancer Institute, under Contract No. SA43-ph-1892 T h e opinions expressed in this been available. Reduction of IV with sodium manuscript are those of t h e airthor.; and not necessarily those of either borohydride-aluminum chloride in diglymeg gave sponsoring agency. an unstable solid which showed a positive nitro(2) For a recent review, see F.H . S e w t h . Quarf Reits. ( L o n d o n ) , 13, prusside reaction and SH infrared absorption at 30 (1959). (3) A. h l . Creighton and I.. S .O w e n , J . Chent. Soc., 1 0 2 1 (19(i0), 3.9 p and was evidently the result of reduction of recently have described t h e preparation of 5,6-dideoxy-5,6-epithio- the thiocarbonyl group. M.'hen this compound was T h e episulfide ring of this compound, 1.2-0-isopropylidene-a-L-idose. however, is situated in t h e sugar ring side-chain, and would be expected t o have a reactivity comparable to t h a t of simple aliphatic episulfides. (4) W. H. Myers and G. J . Robertson, THISJOURNAL, 65, 8 ( 1 9 U ) . ( 5 ) J. C . Crawhall and D . F. Elliott, J . Chcm. Soc., 2071 (1951). (6) Melting points given are for the analyticai sampies.
(7) T h e thioacylethylenimide I V could be rearranged t o the isomeric thiazoline, which showed strong infrared absorption a t 6.25-8.4r (work t o be published). (8) S. Winstein and R. Boschan, THISJOURNAL, 72, 4669 (1950). (9) H. C. Brown a n d E. C. Subba Rau. ibid.. 77, 3164 (1955).
Sept. 5, 1960
COMMUNICATIONS TO THE EDITOR
heated a t 120-130”, the ethylenimine VI11 was formed in 5570 crude yield (from IV), m.p. 153l54”, or isolated as a second crystal form, m.p. 143-145’ (Found: C, 63.4; H, 6.60; N, 5.20); N H absorption a t 3.05 p. By treatment with carbon disulfide and iodomethane under the conditions used to prepare 11, compound VI11 was converted back to IV, and with benzoyl chloride it gave the N-benzoyl derivative, m.p. 195-198” (Found: C, 68.1; H, 5.50; N, 3.95). When the anhydromannoside Vl0 was heated with excess ammonium thiocyanate in 2-methoxyethanol a t 105-1 lo”, the crystalline thiocyanohydrin VI was formed in 75-90Oj, crude yield, m.p. 188-190” (Found: C, 55.8; H , 5.30; S, 9.61). Opening of the epoxide ring of V a t C.3 to give the trans-diaxial product VI as the predominant product is assumed by analogy with other nucleophilic cleavages of I. The conformational rigidity imposed by the 4,6-benzylidene ring obviously prevents the direct epoxide-episulfide transformation that commonly results from the action of thiocyanate ion on epoxides.ll Mesylation of VI gave the sulfonate ester VI1 as a foam in 92% crude yield and treatment of VII, dissolved in 2methoxyethanol, with aqueous sodium hydroxide12 resulted in a 62% yield of the episulfide IX, m.p. 166” (Found: C, 60.2; H, 5.79; S, 11.5). The potentially wide utility of VI11 and I X for further synthetic transformations to compounds such as aminomercapto sugars and diamino sugars which may have interesting chemotherapeutic properties is under investigation. The authors wish to thank Dr. B. R. Baker for valuable suggestions.
4739
100 90
80 70
_’’ A L L- 0 R - NONE ” ASSAY
60
k = O 38 M I N - ’ 50 G-I-P+E-P 0
5
0
40
32
G - 6 - P + E-P”
a z W LL
-RATE
> 30 k
ASSAY
k : 0 9 6 MIN-’
z
t-
u
a
s 20
\ \ \ \
\
IO
0
I 2 3 PHOTOOXIDATION TIME IN M I N U T E S
4
Fig. 1.-Loss of phosphoglucomutase activity on photooxidation as measured by the “rate” assay (A) and the “all-or-none” assay ( 0 ,0 ) .
jiciency of all enzyme species present. The other assay, an “all-or-none” assay, was different in (1945). that i t measured that fraction of the enzyme capable (11) E. E. van Tamelen, THISJOURNAL, 73,3444 (1951). of functioning a t all. To do this, P32-labeled (12) L . Goodman a n d B. R. Baker, i b i d . . 81, 4924 (1969). enzyme was incubated with a large excess of G-1-P DEPARTMEKT OF BIOLOGICAL SCIENCES (or G-6-P) for time intervals sufficient to allow STASFORD RESEARCH INSTITUTE JLMES E. CHRISTESSEN ample opportunity for the intact enzyme to unMESLO PARK, CALIFORNIA LEONGOODMAN dergo a t least 730 complete turnovers. A modified RECEIVED AUGUST4, 1960 enzyme retaining as little as 1/200 of its original activity would therefore lose essentially all its P32-labelduring the assay. ROLE OF HISTIDINE IN PHOSPHOGLUCOMUTASE. The activity remaining as a function of photoT H E USE OF “RATE” AND “ALL-OR-NONE” ASSAYS oxidation time measured by these two assays is sir: shown in Fig. 1. The first order rate constants for The use of chemical modifications to elucidate the activity loss from these plots are 0.9G rnin.-l for “active sites” of enzymes sometimes has resulted in the “rate” assay and 0.38 min.-’ for the “all-orthe designation of a residue as “essential to enzyme none” assay. The striking difference between activity.” I n most of these investigations, how- these two plots can be explained in terms of an ever, a decrease in activity by a factor of twenty activity dependence on two amino acid residues, would have been interpreted as “inactivation.” X and Y , independently oxidized a t rates involving I t would seem desirable, therefore, to describe the constants 0.3s min.-’ and about 0.6 min.-1, such residues as “essential to native enzyme respectively. If oxidation of X reduced enzyme activity” and to attempt to quantitate the de- activity by a factor of >200 while oxidation of Y crease in activity caused by the modification in affected activity to a considerably smaller extent, question. Accordingly different types of activity the “all-or-none” assay would be sensitive to oxiassays have been developed and tested in connection dation of X while the rate assay would be sensitive with methylene blue catalyzed photooxidation of to oxidation of both residues. This explanation could be tested by an extension the enzyme phosphoglucomutase. One of these was the conventional activity assay of the “rate” assay. The correlation between depending on the rate of the catalyzed glucose-l- residues X and U and activity by rate assay is phosphate (G-1-P) to glucose-6-phosphate (G-6-P) expressed mathematically in equation 1. Here conversion. This assay measures an average efA / A 0 = e - ( k x + k y ) t + F ( e - k x r - e-(kx+ky)$) (1) (10) H. R. Bolliger and D. A. Prins, Helu. Chin. A d a , 28, 465
