3402
COMMUNICATIONS TO THE EDITOR
Vol. 84
TABLE I ANTIBACTERIAL .kCTIVITY Compound
I,R=
OF
CEPHALOSPORANIC ACIDS AND N9
NlO
N2G
3% 33 112 107
48 37
21
132
110 101
31
59
15 15
Organism,* pg. t o n ihb i-ti-x2ti
GRADIEST PLATE
TEST8,”
X68
K1
SI
-
;
42 15 >200 110
13 2; >200 >200
41 27 105 102
41
>200
84
13
40
36
10
r
8
11
17
33
25
105
38
10
26
11
15
8
6
5
8
11
--
104
i9
38
48
pCH2-
I. R = D-HO+X!H(SHz)(CH2ja
PENICILLISS I N A
ii)
144
42
109 2 138
I
3;
i3
Results of this type test should be interpreted on a comparative basis only and require use of an internal standard for accuracy. X9 = Shigella sp.; N10, N26 = E . coli; X26, K1 = Klebsiella sp.; X68 = Aerobsctei sp.; S1 = Sh. sonnei.
several Gram negative organisms.B In the group CONJUGATE ANION FORMATION AND ALKYLATION OF a,B-UNSATURATED KETONES’ of penicillins (Table I) no increase in Gram negative activity was observed over that exhibited by Sir: benzylpenicillin. By contrast, cephalosporins with Sodium and potassium salts of tertiary alcohols either thiophene-2-acetyl or furan-2-acetyl side- are efficient bases for the alkylation of a$-unsatuchains a t position 7 showed a t least a threefold rated ketones in the a-position.? The system enhancement of activity over benzylpenicillin. methyl iodide-potassium t-butoxide t-butyl alcohol, Further, all of the cephalosporanic acids showed as has been utilized extensively for the conversion of good or better action than the corresponding peni- A4-3-keto steroids (I),3as well as simple bicyclic cillins. It appears, therefore, that greater potential derivative^,^ into 4,4-dimethyl-A5-3-ketones (VI), for Gram negative activity resides in the cephalo- but certain aspects of this reaction are poorly unsporin structure. derstood. Alkylation even with a limited amount The sodium salt of 7-(thiophene-2-acetamido)- of base and alkyl halide leads to the 4,4dimethyl cephalosporanic acid, which has been given the compound (VII) as the major product and the 4generic name cephalothin, has received extensive monomethyl-A4-3-ketone (VI) as a minor product, clinical evaluation as a broad spectrum antibiotic. indicating that the second alkylation step and/or Results of this work will be reported later. tertiary carbanion formation proceeds more rapidly ROBERT R . CHAUVETTEthan the first alkylation step andi’or secondary EDWINH. FLYSK carbanion formation. Under special reaction conBILLG. JACKSOX ditions (slow addition of 1.2 equiv. of methyl iodide E. R . LAVAGNINO THELILLYRESEARCH ROBERT B. MORIX to the steroid and 1.5 equiv. of potassium t-buA. MUELLER toxide in boiling t-butyl alcohol), dtwaterj found LABORATORIES RICHARD ELI LILLVASD COXPACY RICHARD P. PIOCH that product formation can be reversed with monoR. W. ROESKE methylation (VI) greater than dimethylation (VII) INDIASAPOLIS, ISDIANA C . W. RYAN JOHNL. SPENCER and suggested that the increased steric hindrance EARLEVAS HEYNINCES of methyl at high temperature was the deciding RECEIVED XVCVST1 , 1962 factor. ( 8 ) C. W. Godzeski, C B r o w n , rl. E. Pavey and J. McGowan i n “Antimicrobial Agents a n d Chemotherapy-1961,” Arner. SOC.for hlicrobinlogy, 19G2. p. ,547, See also C . W. Godzeski, G. Brier and r). E . Pare)., in preparation. (0) A 1,eniciilin f I I . R = n-CrHsCH(KHn) haq been reported t o ha\-e greater C r a m negative activity t h a n benzylpenicillin hut tn he ineffertiw V F . penicillin resiitant staphylococci. See G. N.Rollinson a n d S Stevens, R t i f . J f r d . Joxr., ( 2 ) . 191 (1961). We have prepared tlie analogous cephalosporanic acid (I, R = n - C e H C H ( S H d - ) and find t h a t it has substantia! hroad spectrum activity. However, the compound decomposed rapidly i n aqueous solution so t h a t quanti. tati1.e comparisons of xcti\.ity were tinreliable.
(1) Supported in p a r t b y grants A-4044 and C Y - 4 5 5 0 , 7-7 S. Public Health Service. ( 2 ) C j . J. M . Conia and hI. A . Le Craz, Bull. SOL.Chim., 1327 (1960). ( 3 ) (a) R . B. Woqdward, A . A Patchett. D . H . R . Barton. D . A . J. Ives and R. B. Kelly. J . A i m C h e m S o i . , 7 6 , 28.52 (1934); (h) G. Cooley, R. Ellis a n d 1’. Petro\r, .i. Chrtri. S n r , 2998 (1935): (c) 13. J. Ringold and G . Rosenkranz, J . 07,g. C h r m . , 2 2 , 602 (1957); (d) F. Sondheimer and Y . I l a z u r , J . Awl Chew$. Suc., 7 9 , 2906 (19.57). (4) M. Yanagita, h l . Hirakura a n d F. Seki. J . 0 , g . Chrm., 23, 841 (19.58), ( 5 ) S.W. Atwater, J . .1n1.Thu,~t.Six., 8 2 , 2817 (1960).
Sept. 5 , 1962
COMMUNICATIONS TO THE EDITOR
3405
I'anagita and co-workers,4 who found that the reactions which will affect product determination room temperature alkylation of 10-methyl-A4- can occur: (1) alkylation a t C-4, (2) formation of octalin-3-one with methyl iodide-potassium t- the 4-methyl-A4-3-ketone by protonation a t C-6.7 butoxide-t-butyl alcohol readily gave the 4,4- At room temperature and in the presence of excess dimethyl- P-3-one although 4,10-dimethyl- A4-octa- methyl iodide, (1) is faster than (2), which leads to lin-3-one was unreactive under these conditions, the 4,4-dimethyl compound (VII) as the major product. Under the Atwater; conditions equiwere unable to rationalize their results. libration to the 4-methyl-A4-3-ketone ( V I ) beOH comes more rapid than alkylation. Once V I has been formed, conjugate anion production is very slow compared to the unmethylated compound (I) and the major product becomes the 4-monomethylated derivative (VI). b R=CH, H' Protonation of the conjugate anion formed OH ' OH after 4,17-dimethyltestosterone had been in (i5 hour contact with 10 equiv. of base revealed only about 20% deconjugation although from the corresponding alkylation experiment a minimum of 65% of conjugate anion must have been present. m. m. a R=H X decision between preferential protonation of b. R=CH, a t C-6, or double bond shift post-protonation at Our recent finding6that ring A-unsubstituted Ad-3- C-4, readily was provided by deuteration of the keto steroids (I) may be almost completely deconju- conjugate anion with deuterioacetic acid whence gated t o the Aj-3-ones (111) b y the acetic acid proton- 607, deconjugation of the 4methyl compound ation of the conjugate anion (11) which had been occurred demonstrating that protonation did formed with potassium I-butoxide in t-butyl alcohol proceed primarily a t C-4 and the rapid double allowed a study of this alkylation reaction in detail bond rearrangement could be retarded by deuterium and an explanation of the apparent anomalies. substitution a t C-4.y Our results suggested that monomethylation When 4-methyltestosterone (VIa) and 4,17-dimethyltestosterone (VIb) were submitted to decon- would be favored over dimethylation simply by jugation treatment (10 equiv. of potassium t-butox- substituting methyl chloride for methyl iodide ide, 1.5 hours and acetic acid protonation), only which would slow the rate of the second alkylation negligible deconjugation was observed by ultra- while the rate of conjugation to the relatively unviolet and infrared spectroscopy. Comparative reactive 4-methpl-A4-3-one (VI) would not be afalkylations of lia-methyltestosterone (Ib) and of fected. X mixture of A4-cholesten-3-one (400 mg.) 4,l'Twdiniethyltestosterone (VIb) (10 equiv. of and potassium t-butoxide (3 equiv.) in 15 ml. of potassium t-butoxide, 10 minute stirring, then anhydrous t-butyl alcohol was stirred for 5 hours addition of 5 equiv. of methyl iodide with an under nitrogen to pre-form the conjugate anion additional 10 minute reaction time a t room tem- and the solution then saturated with methyl perature) were carried out. Although Ib led to chloride and allowed to stand for 5 hours a t room i 4 % of 4,4,1i-trimethyl conipound3c (VIIbj, VIb temperature. 'i Re-saturation and an additional gave only 6% of 1'IIb and was recovered un- 7 6 hours reaction time gave 4 0 5 4-methyl-A4changed in S47; yield. However, when VTb was cholesten-3-one,3rl 12:; 4,1-dimethyl-A5cholestenand 3r5fi/fi starting material. lTa-lIethylallowed to react with 10 equiv. of potassium tbutoxide for 65 hours prior to the addition of methyl testosterone, under similar reaction conditions, iodide and then allowed 10 minutes reaction time gave 30yc VIb and 11 VIIb. In contrast, with the alkyl halide, 67% of 4,4,17-trimethyl methyl iodide under iden a1 anion preformation compound (IrI Ib) was isolated. The treatment conditions favored 4,4-dimethylation over &monoof testosterone (Ia) and 4-methyltestosterone methylation by ratios of 6: 1 and 13: I with the two (Wa) in a similar fashion gave reaction patterns substrates cited. This altered ratio demonstrates resembling the 17a-methyl cases. the validity of the proposed reaction path. Thus the slow rate of alkylation of the -&methylHOIYARD J. K~stx)i.n FOUNDATION FOR JV-ketones ( V I ) is due to a slow rate of formation WORCESTER EXPERIMESTAL BIOLOGY SUDARSHAS K . M A L I I n T R A o f the coujugate :tilion (5') arid the 4-niethyl-A4-3- SHRRIYSRI-RY, MASSACHUSETTS ketone cannot be the major intermediate in the RECEJVET)J C ~ E 28, 1962 Forniation of the 4,A-dimethyl compound from I. .Just as irreversible protonation of the conjugate (7) It is recognized t h a t protonation a t C-4 also occurs biii thiq anion (11) leads to the deconjugated ketone, product will be readily re-converted t o V h y base. methylation of this anion must yield the 4-methyl(8) A n alternate measure of t h e r a t e of anion furmation i n !-butyl A5-3-ketone (111) as the primary reaction product. alcohol h a s been provided b y quenching of t h e reacti
