Note: Descriptions are shown in the official language in which they were submitted.
~0~50~8
1 This is a divisional application o~ Canadian patent
application serial number 282,526 filed on July 12, 1977.
The invention relates to novel intermediate compounds
useful in the production of anthracyclines which are glycosides
and which are useful in the treatment of tumours in man.
The new compound is 9-desacetyl-9-keto-N-trifluoro-
acetyl-daunorubicin and is prepared by oxidizing N-trifluoro-
acetyl-13-dihydrodaunorubicin in t-butyl alcohol in the
presence of two equivalents of sodium periodate at room
temperature for two hours.
These compounds are useful in the preparation of
daunorubicin derivatives of the general formula I:
O OH
C
~ '
~O HO
NHR
where X is C~ or C~ or~ C = O
~H H
and R is -COCF3 or H.
These compounds are prepared by hydrogenating the
compound of this invention with an alkali metal borohydride,
the amino group of the sugar residue is protected, and the
derivative so protected is oxidized at the 9-position with
a periodate. In the scheme below, daunorubicin (A) is con-
verted into 9-desacetyl-9-keto-N-trifluoroacetyl daunorubicin D.
~v4 ~
10~5028
"
CH3 H ~ NaBH4 ~, CH3 1 OH
A N H2 ¦ ~
NH2 B
1) (CF3C0)20
0 ~ 2) MeOH
OOH R
~ NaI04 ~ HOHCH3
CH3 H ! CH30 OH o
~ HO ~ C
D HCOCF 3 NEICOCF 3
\ ~
O OH Q OH
H ~ H
~ ~OH and ~,J `H
CH30 H 1 CH30 H
HO ~ HO
NHR HR
E: R = COCF3 F: R = COCF3
G: R = H - 2 - H: R = H
'1.0~ 8
1 In the scheme above, the carbonyl group at the l3-
position of daunorubicin A was reduced to the corresponding
alcohol with sodium borohydride. The reaction was carried out
in water at room temperature to give B, isolated as
hydrochloride, in about 80% yield. The resulting diol B was
protected at the amino group of the sugar residue. The N-
trifluoroacetyl group affords the desired protection and can be
removed in mild conditions not affecting the remaining portion
of the anthracycline molecule. The N-trifluoroacetylation was
performed by treatment with trifluoroacetic anhydride, followed
by hydrolysis of 0-trifluoroacetyl groups with methanol giving
a protected derivative C in 74~ yield. The oxidation of C
was carried out in _-butyl alcohol in the presence of two
equivalents of sodium periodate at room temperature for two
hours. The protected daunorubicin D which is insoluble in
the reaction mixture, was obtained in about 50~ yield. The
compound D by treatment with sodium borohydride-cyanide
(NaBH3CN) in acid conditions was converted into an epimeric
mixture of E and F in an approximate ratio 8:l. The separation
Of these compounds by chromatography on a column of silicic
acid, followed by mild alkaline treatment to remove the N-
trifluoroacetyl protective group, gave 9-desacetyl-daunorubicin
G and 9-desacetyl-9-epi-daunorubicin H, isolated as hydro-
chlorides.
The new compounds G and H display antimitotic
activity and are useful therapeutic agents for the treatment
of tumour diseases in humans.
This invention is illustrated by the following
Examples, although each Example does not cover the whole
of the process of the invention.
~09tio28
1 EXAMPLE 1
N-trifluoroacetyl-13- ~ ubicin C (~AR 4)
__
A solution of 3.0 g of daunorubicin hydrochloride in
30Q ml of water was adjusted to pH 9.5 with aqueous 0.1 N sodium
hydroxide and treated with 0.3 g of sodium borohydride at
room temperature for seven minutes. The reaction mixture was
poured into 750 ml of aqueous 0.25 N hydrochloric acid with
vigorous stirring to eliminate the excess reducing agent. The
solution was adjusted to pH 8.6 and extrac-ted with chloroform
until the extracts were no longer coloured. The organic
phase dried over anhydrous sodium sulphate, and evaporated
under vacuum down to 5~ ml volume. The remaining red solution,
adjusted to pH 3.5 (Congo Red) with anhydrous methanolic
hydrogen chloride, was mixed with excess diethyl ether to give
2.8 g of pure 13-dihydrodaunorubicin B, as hydrochloride.
A suspension of 2.8 g of B in 300 ml of chloro~orm
was treated with 20 ml of trifluoroacetic anhydride at 0 for
1 hour. The reaction mixture was evaporated to dryness under
vacuum. The residue was dissolved in 200 ml of methanol and
neutralized with an aqueous saturated solution of sodium
bicarbonate. After 30' at room temperature, the solvent was
eliminated under vacuum and the aqueous solution was extracted
with chloroform until the extrac~s were no longer coloured.
The organic phase was washed with water and dried over anhydrous
sodium sulphate, was evaporated down to 30 ml volume, and
mixed with excess petroleum ether to give 2.3 g of pure N-
trifluoroacetyl-13-dihydrodaunorubicin C: m.p. 164-166C (dec.);
TLC (Thin Layer Chromatography) on Merck Kieselgel 60 F254 using
a chloroform-acetone solvent system (2:1 v/v): Rf 0.25.
10~0~8
1 EXAMPI.E 2
9-Desacetyl-9-keto-N-trifluoroacetxldaunorubicin D (MAR 18)
.
A solution of 2.4 g of C in 120 ml of t-butyl alcohol
was treated with 1.6 g of sodium periodate dissolved in 120 ml
of water. The reaction mixture was stirred at room t'emperature
for two hours. The precipitated compound D was filtered
off, washed with water and dried under vacuum. 1.4 g of pure
D were obtained: m.p. 200C (dec.); T~C on Merck Kieselgel
60 F254 using a chloroform-acetone solven-t system (2:1 v/v):
Rf 0.57.
Elementary analysis: calcd. ~ for C27H24F3NOlo: H 4.18; C 55.95
found % : H 4.26; C 55.65
EXAMPLE 3
_
9-Desacetyl-daunorubicin G (MAR 29) and 9-desacetyl-9-epi-
daunorubicin H (MAR 30)
A solution of 1.7 g of D in 250 ml of dioxan and 50 ml
of water was adjusted to pH 3 with aqueous 1 N hydrochloric
acid and treated with 1 g of sodium borohydride cyanide
(NaBH3CN) at room temperature for 24 hours, the acid condition
being maintained by addition of 1 N hydrochloric acid. The
reaction mixture was mixed with water (300 ml) and extracted
with chloroform (5 x 200 ml). The organic phase, washed with
water and dried over anhydrous sodium sulphate, was evaPorated
to dryness under vacuum. The residue ~1 g~, containing E and
F, was chromatographed on a column of silica gel using
chloroform with increasing amounts of acetone as eluting
agent, to give 0.85 g of pure E, m.p. 204 -206 (dec.); TLC
on Merck Kieselgel 60 F254 using a chloroform~acetone solvent
system (2:1 v/v): Rf 0.44 and 0.1 g of pure F, m.p. 180-182C
lO~SO~B
1 (dec.); Rf : 0.3 in the same conditions as for E. In order to
hydrolyze the N-trifluoroacetyl group E and F were treated
as follows: 50 ml o~ 0.1 N sodium hydroxide were added, after
30' at 0C the pH was adjusted to 8.4 with 0.1 N hydrochloric
acid and the solution was repeatedly extracted with chloroform.
The combined extracts were driea over anhydrous sodium sulphate
and evaporated under vacuum down to 20 ml volume. The solution,
on the addition of the stoichiometric amount of methanolic
hydrogen chloride and diethyl ether, gave a red precipitate
which was collected, washed with diethyl ether and dried under
vacuum. The compound G had m.p. 166 - 167C (dec.); [~]D5 =
+ 282 (c=0.15 in methanol); TLC on Kieselgel plates F254 ~Merck)
with a chloroform acetone solvent system (13:6:1 v/v):
Rf 0.55.
Elementary Analysis:
Calcd. % for C25H27NOgHCl : H 5.42; C 57.52; N 2.68
found : H 5.45; C 57.16; N 2.42
Compound H had m.p. 176C (dec.), Rf 0.4 in the same conditions
as for compound G.
TABLE 1
Activity of doxorubicin [NSC 123127], 9-desacetyl-
daunorubicin (G~ ~NSC 268708] and 9-desacetyl-9-epi-daunorubicin
(H) [NSC 268709] on P 388 lymphocytic leukemia in C.D.F. male
mice (tumour inoculum 106 cells intraperitoneally (ip)~.
Treatment ip on days 1 to 9
- 6 -
10~;02~
1Compoun~_ Dose m~/kg T/C
Doxorubicill 4 83
2 180
1 171
0.5 142
0.25 152
73
12~5 228
6.25 180
3.13 174
1.56 155
H 25 66
12.5 66
6.25 171
3.13 157
1~ 1.56 142
a Experiment number 4108 - Data obtained under auspices
of NCI. Screener : A.D. LITTLE INC.
b Median survival time expressed as percent of
untreated controls.
TABLE 2
Activity of doxorubicin [NSC 123127] and 9-desacetyl-
daunorubicin (G) [NSC 268708] on P 388 lymphocytic leukemia
in CDFl male mice (tumour inoculum 10 cells, ip). Treatment
ip on days 5, 9, 13 a,
20Compound Dose mg/kgT/C b
Doxorubicin 16 120
8 163
4 136
22 125
1 125
G 113 116
181
37.5 135
lS.8 145
9.4 133
4.7 109
a Experiment number 4832. Data obtained under auspices
of NCI. Screener : A.D. LITTLE INC.
b Median survival time expressed as percent of untreated
controls~
~0950;~8
1 Although the disclosure describes and illustrates
a pxeferred embodiment of the invention, it is to be under-
stood that the invention is not restricted to -this particular
embodiment.
