2
[15. IH. 1947] Kurze Mitteilun~en - Brief reports 10 7 The Bromination of saturated 3-Ketosteroids with N- Brorno- Imides In recent issues of this journal, reports have appeared on the reaction of unsaturated ketones with N-bromo- succinimide. Buu-Hoi t reported that in aliphatic ke- tones (mesityl oxide type), the bromine entered the a-position, whereas ~{EYSTRE and WETTSTEIN 2 found that in Ad-3-ketosteroids (e, g. testosterone or pro- gesterone) bromination occurred preferentially in the allyl position. As far as we are aware, only two public- ations have appeared on the bromination of saturated ketones with N-bromo-imides. V~'OHL a brominated ace- toacetic ester and Scamp and KARRt~R 4 reported the successful bromination of cyclohexanone and of a keto- pelargonic acid derivative. We were interested in studying the bromination of saturated 3-ketosteroids with these reagents because (a) if successful, it would afford a means of brominating without the simultaneous liberation of hydrogen bro- mide whick may cause subsequent rearrangements, and (b) to determine whether the conventional rules 5 set forward for the reaction with bromine (substitution at C~ in members of the allo and at C4 in those of the normal series) would hold also for this type of reagent. It was found that by refluxing equimolar quantities of steroid ketone and N-bromosuccinimide or N-bromo- phthalimide in carbon tetrachloride solution in strong lightL reaction was complete after one to two minutes as evidenced by sudden decolorization and quantitative recovery of the haIogen-free imide. Evaporation of the filtrate to dryness in vacuo and recrystallization from a suitable solvent yielded the corresponding mono- brominated steroid ketone, which in each case was found to be identical with the corresponding sample prepared by the conventional bromine-acetic acid method. The yields obtained by either method are com- parable. In the absence of light, the reflux time had to be extended to about one-half hour to obtain similar re- sults. Cholestanone-3, dihydrotestosterone hexahydro- benzoate, and methyl 3-ketoalloetiocholanate gave the corresponding 2-bromo derivatives whereas eopro- stanone-3 and methyl 3-keto-12-hydroxycholanate led to the respective 4-bromo compoundsL The above re- sults indicate that bromination of saturated 3-keto steroids by this method is feasible and that the substi- tution takes place at the same carbon atom and in the same stereochemical position as found for brominations in acetic acid s Furthermore, it was of interest to us to determine whether additional bromination of the bromoketones could be accomplished with these reagents. Refluxing 1 Buu-Ho~, Exper. 2, 310 (1946). 2 MEYS'rRE and WETTSTEIN, Exper. 2, 408 (1946). a WOHL, Ber. 52, 51 (1919). - VVoHLand JASCHINOWSKI, ib. 54, 476 (1921). 4 SCrLmD and KARRER, Helv. chim. aeta 29, 573 (1946). 5 Cf.: BUTENANDTand VV'OLFF, Ber. 6,~, 2091 (1935). s CI.: MTESCHER and co-workers, Helv. chim. acta 28, 1252, 1497 (1945); lb. 29, 33, 627 (1946). r In the latter case the crude bromination product, which was difficult to purify, was dehydrobrominated with pyridine to give methyI Aa-3-keto-12-hydroxycholenate, m.p. 145-147,5 ° C, [c~]~ 3 -- 80-3 0 (acetone), nmx. at 242m/~ (Iog~.. ~ ~ 4.2g in cthanol), in ca. 30% overall yield. RIEC, EL and MclsrosiL J. amer. chem. See. OO, 1099 (1944) obtained this compound in 35% yield, m. p. 144-145 ° C by the conventional bromination method followed by treatment with pyridine. BURC~HARD and REICHSTEIN, Heir. 17 chim. acta 2,5, g21 (1942) reported m.p. 150-152o C, ]~]D =: - 80.9 o (acetone). of 2-bromocholestanone with a sIight excess over the equimolar amount of N-bromosuccinimide in carbon tetrachloride solution on exposure to strong light for one minute gave 51% of crude 2, 2-dibromocholestanone. The purified product gave no depression in m.p. on admixture with an authentic sampleL It is interesting to note that only starting material could be recovered when the same reaction was carried out in the absence of strong light, notwithstanding the fact that the reactiou time was prolonged to one and one-hail hours. This is in contrast to the above-mentioned monobro- minatiou of cholestanone, which was essentially com- plete after one-half hour in the dark. CARL DJERASSI and CAI':SAR R. SCHOI.Z Research Department, Division of Chemistry, Ciba Pharmaceutical Products, Inc., Summit, New Jersey, 1;.b.A., January 6, 1947. Zusammen/assung Die Bromierung yon ges~ittigten 3-Keto-steroiden mit N-Brom-succinimid oder N-Brom-phthalimid liefert die 2-Brom-3-keto-steroide bei Verbindungen, die der aUo-Reihe angehiiren, und die 4-Brom-3-keto-steroide bei Vertretern der normaI-Reihe. Die weitere Bromie- rung eines 2-Brom-3-ketons zut~'l 2,2-l)ibrom-3-keton ist m6glich. 1 2,'2-1)ibromocholestanone-3, m.p. 145 1470 C, [~]~2 = ~ lOiO (chloroform} was obtained by the recently described method (WILD~ and I)JEI~AssL J. amer. chem. So(:. 6S, 21i5, footnote 22a (1946). Its structure has been proven by conw,rsion to A l-2-bromo- cholestenone-3, m.p. 9I'5.92"50C, [~]~¢ = ] 37"4o (ehlorofornd, nlax. a~ 255"~)lllt~ (tog2. ~ = 3"93 in ethanol). The details will appear in a sul)sequent publication fronl this laboratory. Action de l'eau oxyg6n6e sur un ana6robie strict Au cours de leurs travaux sur Faction toxique de l'oxygSnc, ISLLIOT et LIm.;TL STADIE 2, DICKENS a, MANN et QUASTEL 4 ont montrd que cette action s'expliquait par t'empoisonnement de eertaines diastases. Nous avons de notre c6t6 constat~ que: 10 Lorsque l'on ajoute de faibles quautit~s d'eau oxy- g6n6e h une suspension de Cl. saccharobutyricum dans un tampon de phosphate renfermant du glucose, en atmosphere d'azote, on constate nn arr& de la pro- duction d'H 2 qui reprend, apr~s un temps de latence, avec une vitesse 6gale ~ celle du t~moin. 2 0 Pour des quantit~s plus fortes d'eau oxygdn6e, le temps de latence augmente et la reprise de la production d'Hz se fait ~ une vitesse plus Iaible que celle du t6moin. 3 0 Enfin ~ partir d'une certaine concentration en eau oxyg6n6e, Farr6t de la production d'H, est d6finitiI. 4 a On a done une concentration provoquant un arrbt r~versible et une concentration provoquant un arr~t irr6versible. Ceci est ~ rapprocher des ancienes constata- tions de QUASTEL et STEPHENSON 5 sur l'action de l'eau oxyg6nde dans Ia croissance de CL sporogenes. 50 Les quantitfis d'eau oxyg6n6e n6cessaires pour pro- duire le ph~,nom~ne sent fonction du poids des bac- 1 ELL1OTet IARET, J. biol. Chem. 143, 227 (1942). 2 ST,~mE, RInGs et HANGAARD, Amer. J. reed. Sci. 207, 84 (1944). a DICKENS, Bioch. J. 40, 145 et 171 (1946). 4 MANNet QUASTEL,Bioch. J. 40, 139 (1946). 5 QUASTEL et STEPIII4iNSON, Bioch. J. 20, 1125 (1926}.

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Page 1: Action de l'eau oxygénée sur un anaérobie strict

[15. IH. 1947] Kurze Mitteilun~en - Brief reports 10 7

T h e B r o m i n a t i o n of s a t u r a t e d 3 - K e t o s t e r o i d s w i t h N - Brorno- I m i d e s

In r e c e n t issues of t h i s journa l , r e p o r t s h a v e a p p e a r e d on t h e r eac t ion of u n s a t u r a t e d ke tones w i t h N - b r o m o - succ in imide . B u u - H o i t r e p o r t e d t h a t in a l ipha t i c ke- tones (mesi ty l ox ide type) , t h e b r o m i n e e n t e r e d t h e a -pos i t ion , w h e r e a s ~{EYSTRE a n d WETTSTEIN 2 f o u n d t h a t in Ad-3-ke tos te ro ids (e, g. t e s t o s t e r o n e or pro- ges terone) b r o m i n a t i o n occur red p re fe ren t i a l l y in t h e al lyl pos i t ion . As far as we are aware , only two publ ic- a t i ons h a v e a p p e a r e d on t h e b r o m i n a t i o n of s a t u r a t e d ke tones w i t h N - b r o m o - i m i d e s . V~'OHL a b r o m i n a t e d ace- toace t i c e s t e r a n d S c a m p a n d KARRt~R 4 r e p o r t e d t h e successful b r o m i n a t i o n of c y c l o h e x a n o n e a n d of a ke to- pe la rgonic acid de r iva t ive .

W e were i n t e r e s t e d in s t u d y i n g t h e b r o m i n a t i o n of s a t u r a t e d 3 -ke tos t e ro ids w i t h t h e s e r e a g e n t s because (a) if successful , i t wou ld a f fo rd a m e a n s of b r o m i n a t i n g w i t h o u t t h e s i m u l t a n e o u s l ibe ra t ion of h y d r o g e n bro- mide w h i c k m a y cause s u b s e q u e n t r e a r r a n g e m e n t s , and (b) t o d e t e r m i n e w h e t h e r t h e c o n v e n t i o n a l ru les 5 se t f o r w a r d for t h e r eac t ion w i t h b r o m i n e ( subs t i t u t i on a t C~ in m e m b e r s of t h e allo a n d a t C4 in t h o s e of t h e normal series) wou ld ho ld also for th i s t y p e of r eagen t .

I t was found t h a t by r e f lux ing e q u i m o l a r q u a n t i t i e s of s t e ro id ke tone a n d N - b r o m o s u c c i n i m i d e or N - b r o m o - p h t h a l i m i d e in c a rbon t e t r a c h l o r i d e so lu t ion in s t r ong l ightL reac t ion was c o m p l e t e a f t e r one to t w o m i n u t e s as e v i d e n c e d b y s u d d e n deco lor iza t ion a n d q u a n t i t a t i v e r e cove ry of t h e haIogen- f ree imide . E v a p o r a t i o n of t he f i l t r a te to d r y n e s s in vacuo a n d rec rys ta l l i za t ion f rom a su i t ab l e so lven t y i e lded the c o r r e s p o n d i n g mono- b r o m i n a t e d s t e ro id ke tone , w h i c h in each case was found to be iden t i ca l w i t h t h e c o r r e s p o n d i n g s amp le p r e p a r e d b y t h e c o n v e n t i o n a l b r o m i n e - a c e t i c ac id m e t h o d . T h e yie lds o b t a i n e d b y e i the r m e t h o d are com- parab le . In t he absence of l ight , t h e ref lux t ime had to be e x t e n d e d to a b o u t one -ha l f hou r to ob t a in s imi la r re- sul ts . Cho les tanone-3 , d i h y d r o t e s t o s t e r o n e h e x a h y d r o - benzoa te , a n d m e t h y l 3 -ke toa l l oe t i ocho l ana t e gave t h e c o r r e s p o n d i n g 2 -b romo d e r i v a t i v e s whe rea s eopro- s t a n o n e - 3 a n d m e t h y l 3 - k e t o - 1 2 - h y d r o x y c h o l a n a t e led to t h e r e spec t i ve 4 - b r o m o c o m p o u n d s L T h e a b o v e re- su l t s i n d i c a t e t h a t b r o m i n a t i o n of s a t u r a t e d 3-ke to s t e ro ids by th i s m e t h o d is feas ib le a n d t h a t t h e subs t i - t u t i o n t akes p lace a t t h e s a m e c a r b o n a t o m a n d in t h e s ame s t e r e o c h e m i c a l pos i t i on as f o u n d for b r o m i n a t i o n s in ace t ic ac id s

F u r t h e r m o r e , i t was of i n t e r e s t to us t o d e t e r m i n e w h e t h e r a d d i t i o n a l b r o m i n a t i o n of t h e b r o m o k e t o n e s cou ld be a c c o m p l i s h e d w i t h t h e s e r eagen t s . R e f l u x i n g

1 Buu-Ho~, Exper. 2, 310 (1946). 2 MEYS'rRE and WETTSTEIN, Exper. 2, 408 (1946). a WOHL, Ber. 52, 51 (1919). - VVoHL and JASCHINOWSKI, ib. 54,

476 (1921). 4 SCrLmD and KARRER, Helv. chim. aeta 29, 573 (1946). 5 Cf.: BUTENANDT and VV'OLFF, Ber. 6,~, 2091 (1935). s CI.: MTESCHER and co-workers, Helv. chim. acta 28, 1252,

1497 (1945); lb. 29, 33, 627 (1946). r In the latter case the crude bromination product, which was

difficult to purify, was dehydrobrominated with pyridine to give methyI Aa-3-keto-12-hydroxycholenate, m.p. 145-147,5 ° C, [c~]~ 3 -- 80-3 0 (acetone), nmx. at 242m/~ (Iog~.. ~ ~ 4.2g in

cthanol), in ca. 30% overall yield. RIEC, EL and MclsrosiL J. amer. chem. See. OO, 1099 (1944) obtained this compound in 35% yield, m. p. 144-145 ° C by the conventional bromination method followed by treatment with pyridine. BURC~HARD and REICHSTEIN, Heir.

17 chim. acta 2,5, g21 (1942) reported m.p. 150-152 o C, ]~]D =: - 80.9 o (acetone).

of 2 - b r o m o c h o l e s t a n o n e wi th a sI ight excess over t he e q u i m o l a r a m o u n t of N - b r o m o s u c c i n i m i d e in ca rbon t e t r a c h l o r i d e so lu t ion on e x p o s u r e to s t r o n g l ight for one m i n u t e gave 51% of c rude 2, 2 - d i b r o m o c h o l e s t a n o n e . T h e pur i f i ed p r o d u c t gave no dep res s ion in m . p . on a d m i x t u r e w i t h an a u t h e n t i c s a m p l e L I t is i n t e r e s t i n g to no te t h a t on ly s t a r t i n g ma t e r i a l could be r ecove red when t h e s a m e r eac t ion was ca r r i ed o u t in t h e a b s e n c e of s t r o n g l ight , n o t w i t h s t a n d i n g t h e fac t t h a t t h e reac t iou t i m e was p r o l o n g e d to one a n d o n e -h a i l hours . This is in c o n t r a s t t o t h e a b o v e - m e n t i o n e d m o n o b r o - m i n a t i o u of cho l e s t anone , wh ich was essen t i a l ly com- p le te a f t e r o n e -h a l f h o u r in t h e dark .

CARL DJERASSI and CAI':SAR R. SCHOI.Z

Res ea r ch D e p a r t m e n t , Divis ion of C h e m i s t r y , Ciba P h a r m a c e u t i c a l P r o d u c t s , Inc . , S u m m i t , New Je r sey , 1; .b .A. , J a n u a r y 6, 1947.

Z u s a m m e n / a s s u n g

Die B r o m i e r u n g yon ges~it t igten 3 - K e t o - s t e r o i d e n m i t N - B r o m - s u c c i n i m i d ode r N - B r o m - p h t h a l i m i d l iefer t die 2 - B r o m - 3 - k e t o - s t e r o i d e bei V e r b i n d u n g e n , die der aUo-Reihe angehi i ren , und die 4 - B r o m - 3 - k e t o - s t e r o i d e bei V e r t r e t e r n de r normaI-Reihe. Die we i t e r e Bromie - r u n g e ines 2 - B r o m - 3 - k e t o n s zut~'l 2 , 2 - l ) i b r o m - 3 - k e t o n ist m6gl ich.

1 2,'2-1)ibromocholestanone-3, m.p. 145 1470 C, [~]~2 = ~ lOiO (chloroform} was obtained by the recently described method (WILD~ and I)JEI~AssL J. amer. chem. So(:. 6S, 21i5, footnote 22a (1946). Its structure has been proven by conw,rsion to A l-2-bromo- cholestenone-3, m.p. 9I'5.92"50C, [~]~¢ = ] 37"4 o (ehlorofornd, nlax. a~ 255"~)lllt~ (tog2. ~ = 3"93 in ethanol). The details will appear in a sul)sequent publication fronl this laboratory.

A c t i o n d e l 'eau o x y g 6 n 6 e s u r u n ana6rob ie s t r i c t

Au cours de leurs t r a v a u x sur Fac t ion t o x i q u e de l 'oxygSnc, ISLLIOT et LIm.;TL STADIE 2, D I C K E N S a, MANN et QUASTEL 4 o n t m o n t r d que c e t t e ac t ion s ' e x p l i q u a i t p a r t ' e m p o i s o n n e m e n t de ee r t a ines d ias tases . Nous a v o n s de n o t r e c6t6 cons t a t~ que :

10 L o r s q u e l 'on a j o u t e de faibles quau t i t~ s d ' e a u oxy- g6n6e h une su spens ion de Cl. saccharobutyricum d a n s un t a m p o n de p h o s p h a t e r e n f e r m a n t du glucose, en a t m o s p h e r e d ' a zo t e , on c o n s t a t e n n a r r & de la pro- d u c t i o n d ' H 2 qui r ep rend , apr~s un t e m p s de la tence , avec une v i tesse 6gale ~ celle du t~moin.

2 0 P o u r des q u a n t i t ~ s p lus fo r t e s d ' e a u oxygdn6e , le t e m p s de l a t ence a u g m e n t e e t la repr i se de la p r o d u c t i o n d ' H z se fa i t ~ une v i tesse plus Iaible que celle du t6moin .

3 0 E n f i n ~ p a r t i r d ' u n e ce r t a ine c o n c e n t r a t i o n en eau oxyg6n6e, Fa r r6 t de la p r o d u c t i o n d ' H , es t d6fini t i I .

4 a On a done une c o n c e n t r a t i o n p r o v o q u a n t un a r rb t r~vers ib le e t une c o n c e n t r a t i o n p r o v o q u a n t un arr~t i r r6vers ible . Ceci est ~ r a p p r o c h e r des anc i enes c o n s t a t a - t ions de Q U A S T E L e t S T E P H E N S O N 5 s u r l ' a c t i on de l 'eau oxyg6nde d a n s Ia c ro i s sance de CL sporogenes.

50 Les quan t i t f i s d ' e a u oxyg6n6e n6cessaires pour pro- dui re le ph~,nom~ne s e n t f o n c t i o n du poids des bac-

1 ELL1OT et IARET, J. biol. Chem. 143, 227 (1942). 2 ST,~mE, RInGs et HANGAARD, Amer. J. reed. Sci. 207, 8 4 (1944) . a DICKENS, Bioch. J. 40, 145 et 171 (1946). 4 MANN et QUASTEL, Bioch. J. 40, 139 (1946). 5 QUASTEL et STEPIII4iNSON, Bioch. J. 20, 1125 (1926}.

Page 2: Action de l'eau oxygénée sur un anaérobie strict

108 Br~ves communications - Brevi comunicazioni [EXPERIENTIA VOL. III[3]

t6ries. Mais les r6sultats sont coh6rents. Pour 1 mg de bact6ries (poids sec) la limite de r6versibilit6 complete est a t te inte avec 6 y d 'HiOz, celle de l ' irr6versibilit6 avec 11 h 13 7 dans un volume de 2 cm 3.

6 o Ces chiffres ne correspondent pas aux quanti t6s maximum d'eau oxyg6n6e que peuvent fixer les bac- t6ries. Ces quanti t~s sont variables: 80 ~ 180y par mg (poids sec) de bact6ries vivantes, 60 ~ 140 y de bact~ries tu6es par la chaleur.

70 L 'eau oxyg~n6e semble donc agir d 'abord sur une substance x responsable du d6gagement d ' H , 5. par t i r du glucose ou de ses produits de d6gradation, suivant un m6canisme tel que la fixation d 'un ~quivalent d 'oxyg~ne donne une combinaison r*versible, celle de deux une combinaison irr6versible. Peut-~tre s 'agit-il de la diastase de LIPMANN, qui libbre aux d6pens de l 'acide pyruvique de I 'H, et du COy On constate en effet apr~s addit ion d'eau oxyg6n6e, lorsque le ph6no- m~ne est r6versible, une diminution de la vitesse de pro- duct ion de CO,, suivi au bout d 'un certain temps, d 'une reprise A une valeur ~gale A celle du t6moin.

Ceci concorde avec la suggestion de MANN et QUASTEL 1 qui pensent que dans le cerveau, la pyruva te oxydase, en t an t que thiol-enzyme est le facteur qui est empoi- sonn6 par de hautes tensions d 'oxygbne ou par l 'eau oxyg6n~e.

E. AUBEL, A . J . ROSENBERG et J. SZULMAJSTER

Ins t i tu t de biologic physico-chimique, Paris, le 15 jan- vier 1947.

Summary

A quan t i t a t ive s tudy on the action of H202 upon Cl. saccharobutyricum shows tha t the pr imary action is produced upon a first substance X, very likely an enzyme, following a mechanism such as one equivalent of oxygen gives a reversible combination, and two equivalents an irreversible combination.

1 MANN et QUASTEL, Bioch. J. 40, 139 (1946).

Hemmungswirkungen verschiedener Indophenole auf die Wasserstoff-

peroxydzersetzung durch Blutkatalase

Schon im Jahre 1928 wurde v o n ALEXEJEW und RUSSINOWA 1 gezeigt, dab verschiedene Wasserstoff- akzeptoren, z. B, Methylenblau, =-Dinitrophenol und Chinon, die Akt iv i tg t der Blutkatalase zu hemmen im- stande sind. Wir haben die Angaben dieser Autoren nachgeprtif t und konnten sie weitgehendst best~tigen. In einer fr/iheren Arbeit * haben wir dann eine Anzahl verschieden subst i tuier ter Chinone auf ihre Hemm- wirkung gegentiber der Blutkatalase untersucht und konnten dabei feststellen, dab bei sonst ~ihnlicher Kon- s t i tu t ion das Oxyda t ions -Redukt ions -Po ten t ia l dieser Stoffe einen EinfluB auf die St~rke der Hemmung be- sitzt. Allerdings konnten wir keine vSitige Propor- t ional i t~t nachweisen, es mfissen also auch andere Fak- toren bes t immend wirken.

Wir haben nunmehr eine Anzahl verschiedener Indo- phenole, die wir fiir einen anderen Zweck dargestell t hatten, auf ihre Hemmwirkung auf die Akt iv i t~ t der

I A. ALEXEJEW und K, RUSSrNOWA, Bull. Inst. Rech. biol. Perm, 6, 4'25 (19~8).

2 0 . HOFFMANN-OSTENHOF und E. BIACH, Mh. Chem. (im Druck).

Katalase untersucht . Bei der nahen Verwandtschaf t der Indophenole mit den Chinonen war ein Hemmeffek t yon vornherein zu erwarten und wir konnten einen solchen auch nachweisen. Die gefundenen Hemm- wirkungen waren in vielen F/~llen sehr betr/ichtlich und fiberstiegen bei einigen Indophenolen die st~rksten der bei den Chinonen gefundenen Hemmwer te . Eine Ab- h/ingigkeit yore Oxyda t ions -Redu kt ions-Potent ia l konn- te nicht festgestetlt werden; allerdings ist diese Gr6Be nicht bei allen untersuchten Stoffen bekannt.

Bei diesen Messungen wurde die gleiche Methodik und ein gleichartiges Blutkata lasepr~para t wie in der oben zit ierten Arbei t 1 ve rwand t ; die prozentuelIen Hemmungswer te sind mi t einer Fehlergrenze yon h6chstens =k2% reproduzierbar. In tier Tabelle geben wir die erhal tenen Wer te nur flit eine einzige Konzen- t ra t ion an; zum Vergleich ist auch der entsprechende Hemmungswer t eines der st/~rkst wirksamen Chinone (p-Benzochinon) bei derselben Konzentra t ion angeftihrt.

Tabdle I Hemmung der Aktivit/~t von Blutkatalase durch verschiedene lndo- )henole in 10-dmolarer Konzentration im Versuchsansatz (PH = 7).

Prozen- Substanz tuelle

Hemmung

Phenol-indophenol Phenol-indokresol Phenol- indothymol 2-Chlorphenol-indophenol 2, 6-Dichlorphenol-indophenol 2, 6- Dibromphenol- indophenol 2, 6-Dichlorphenol-indokresol 2, 6-Dibromphenol-indokresol 2, 6-Dichlorphenol-indoguaj akol 2, 6- Dibromphenol- indoguaj akol 2, 6-Dichlorphenol- Y-bromindophenol 2, 6-Dibromphenol- 3 ' -bromindophenol 2, 6-Dichlorphenol- indothymol 2, 6- Dibromphenol- indothymol 2, 6-Dichlorphenol- indonaphthol 2, 6- Dibromphenol- indonaphthol p-Benzochinon

25 42 19 20

3 18 12

7 22 20 25 32

0 5

12 15 24

Es scheint nicht mSglich zu sein, die durch Indo- phenole oder auch durch Chinone bewirkte H em m ung durch Zugabe yon Redukt ionsmi t te ln riickg~ngig zu machen. Hierbei mul3 allerdings bemerkt werden, dab Redukt ionsmi t te l ebenfalls imstande sind, eine betr/~cht- liche Hemmwirkung auf die Kata laseakt iv i t / i t aus- zufiben. So wurde unser BlutkatalaseprS.parat yon Natr iumhydrosulf i t in 10 -*molarer Konzentra t ion in seiner W'irkung um 20% gehemmt. Auch organische XVasserstoffdonatoren zeigen eine Hemmwirkung , so hemmte Hydrochinon in 10-dmolarer Konzentra t ion die Blutkatatase zu 31%; SEIDE 2 berichtet fiber gr613en- ordnungsm~Big entsprechende Hemmungen yon kristal- lisierter Leberkatalase durch Phenylhydroxylamin , Aminophenole und /~hnliche Substanzen. Vielleicht las- sen sich auch die in der itlteren Li tera tur beschriebenen Kata lasehemmungen dutch Ferri-, Cupro- und Mangano- salze als Oxydations- bzw. Redukt ionswirkungen deuten.

I O. HOFFMANN-OSTENHOF und E. BtACH, Mh. Chem. (ira Druck). 2 G. SEn)E, Biochem, Z. 30,% 175 (1941).