COMRIUNICATIONS TO WE EDITOR
5076
sterically more conipact CN groups of CH2(CN)s lead to a deviation of only 1.5 powers of ten greater rate, according to equation (a),than that observed. The results listed in Table I also suggest that saturation of resonance stabilization in the ionization state contributes to the failure of equation (2) since the deviations increase with increasing values of 2 U R - . 5
Vol. 79
which gives a positive Morgan--Elson test for 2acetamido aldoses, reduces Fehling solution inore readily than 111, and consumes one mole of base to yield formic acid and the 2-acetamid0-2~3-dideoxypentose, V (m.p. 128-130", [ a I z 3-SI" ~ (c, 1.0 in ethanol); calcd. for CiHlnN04: C, 47.99; H, 7.48; S , S.00. Found: C, 47.86; H , i.41; N , S.09).
( 5 ) T h e logarithms of t h e ionization constants of substitutcd methanes (reference 4) also appear to follow equation (2) with ,OR 7, a n d log K, of m e t h a n e C -40. However. t h e ionization 30, P I constants for CHaSOzCHa a n d C H a C S are so crude t h a t t h e q u a n t i t a tive significance of t h e relationship is uncertain. T w o points a r c worthy of comment. Nitromethane deviates (greater acidity) b y a b o u t six log u n i t s , which is t h e s a m e magnitude a s t h e deviation of t h i s compound f r o m t h e norm i n a plot of log A1 2's. log R a (cf. Fig. 1, reference 4). T h u s t h e deviation apparently c a n he a t t r i b u t e d t o t h e abnormally slow recombination r a t e of "nitrocarbanion" with hydrogen ion. On t h e o t h e r h a n d , t h e relationship is followed reasonahly well b y both CHz(CN)l a n d C H ( C S ) 3 . (CHCO)?CW2 and (CHaCO)\C H deviate substantially (weaker acids) in t h e direction expected for steric inhibition of resonance i n t h e carbanion ion.
I
COLLEGE OF CHEMISTRY ASD PHYSICS THEPENNSYLVANIA STATEUNIVERSITY UNIVERSITY PARK,PENNSYLVANIA ROBERT IV. TAW,JR. RECEIVED XLXXJST 7 , 1957 THE
STRUCTURE OF MYCOSAMINE
Sir: We wish to report in this communication on the structure of an amino-sugar mycosamine, which represents the nitrogen-containing moiety of the j. antifungal antibiotics, nystatin,2 C4fiH77N019,3s4 1,5 This amino and amphotericin B, C46HT3N020. sugar was isolated in the form of its tetraacetatel from the mixture of products resulting from the sulfuric acid catalyzed acetolysis of either the antibiotics or their hydrogenated derivatives. Structure I is assigned t o the parent amino sugar on the basis of the following evidence: Chromatographic fractionation on alumina of the chloroform soluble portion of the acetolysis products yielded tetraacetylmycosamine (TI m.p. j. 159-161°, [ c Y ] ~ ~+39' D (c, 1.0in ethanol); calcd. I-i I-I 110 0 1I for CtjHgN04.4CH3CO: 50.75; H, 6.39; hT, o=c c-0 cod 4.23; acetyl (total), 32.0. Found: C, 50.40; + H, 6.44; K j4.26; acetyl, 50.9),hydrolyzable by .H20 barium niethoxide in methanol to N-acetylinycosPO\ CII, CHI CI310 amine' (111, m.p. 191-192", [ a I z 3 D -46' (c, 1.0 CI-IJO VIIIa 1 7 I I 11) in ethanol) ; calcd. for C6H12N04.CH3C0: C, 46.82; H, '7.37; K, 6.83; N-acetyl, 21.0. Found: C, Furthermore, methyl N-acetylmycosaniinide V I 46.58; H, 7.22; N, '7.07; N-acetyl, 21.2): which reduces hot Fehling solution only slowly and gives (m.p. 168-170", [ f f I z 3 D +47" (c, 0.9 in ethanol); a positive iodoform test. Treatment of I11 with calcd. for C9HI7NO5: C, 49.30; H, 7 3 2 ; N, (i.39; periodic acid (consumption 1 mole) yielded 2-acet- OCH3, 14.1. Found: C, 49.00; H, 7.56; K, 6.13; ainido-3-hydroxy-4-formoxypentanal1 1 7 (amor- OCH3, 13.5), obtained from 111 with methanolic phous, calcd. for C8Hl3NO5: C, 47.29; H , fi.45; hydrogen chloride, was reduced TT. ith lithium N, 6.85. Found: C, 47.22; H , 6.84; N, 6.93, aluininuni hydride to methyl N-ethyliiiycosaininide, Y I I , (m.p. 90.5-92.5', [Cylz3D +25" (c, 1.0 (1) J. D . D u t c h e r t M . B. Young. J. H . Sherman, W.E. Hihhits a n d in n a t e r ) ; calcd. for C9Hl9KO4. C, ,5266; H, D. R. Walters, "Antibiotics Annual," 1966-1957, Medical Encyclupedia, Inc., New York, N. Y., 1956, p. 866. 9.33; N, 6.83; mol. weight, 205. Found: C. (2) T h e E. R.Squibb a n d Sons t r a d e m a r k for nystatin is "5lyco52.51; H, 9.19;X, 6.84; neut. eq. (perchloric acid statin." titration), 211), and this base was degraded with (3) J. D . Dutcher, G. Boyack a n d S. FOX."Antibiotics Annual," sodium periodate (2 moles) t o the known6 D'1953-1956, Medical Encyclopedia, I n c . , New Y o r k , 19.53 11. 191. ( 4 ) J. D . Dutcher, D. R. Walters and 0 . P. Wintersteinrr, " ' I ' h ~ ~ r n i ~ v ~ n c ~ l i ~ ~ ~ v - ~ - n i c t ~ i y l d i g aldehyde l y c o l i c l r I I I (111p.
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of I'ungiis Disenses," T,ittlr, Flrown :ii1(1 C < > n n p i i i y ,l { o , t o ~ i , \ I u i lKh5, 1'. 168. ( 5 ) J . Vandrlintte, J. I,. Wnclitel : I I I < I 1,). '1'. Stiller, ' ' A i 1 1 .\iiii~iiil," 1!155-I!l,76, h'ledical E n c v v I o I ~ ~ i l il,ni ,c . , l!l.*)A, 1 3 6 i 7
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