Methyl steroids. Studies on the synthesis of 4-methyl-and 4,4-dimethyl-25-hydroxycholestan-3-one derivatives

Article abstract of DOI:10.1135/cccc20071319

The synthetic routes to 25-hydroxy derivatives of 4-methylcholest-4-ene and 4,4-dimethylcholest-5-ene from methyl lithocholate and methyl 3β-acetoxy-24-homochol-5-en-25-oate (6) have been investigated. The cholest-5-ene-3β,25-diol (7), readily available from 6, was transformed in a few steps into the title compounds. It was also found that bromination of 24-acetoxy-5β-cholan-3-one (1) and of its enol acetate followed by dehydrobromination is not a regioselective reaction. Formation of mixtures of 2β-bromo-3-oxo and 4β-bromo-3-oxo compounds, which gave mixtures of 24-acetoxychol-4-en-3-one (4) and 24-acetoxy-5β-chol-1-en-3-one (5) of similar polarity was observed. 4-Methyl-25-hydroxycholest-4-en-3-one (14) and 4-methyl-25-hydroxycholesta-1,4-dien-3-one (16) are potential substrates for the preparation of 4-methyl analogs of vitamin D₃.

Full text of DOI:10.1135/cccc20071319

Methyl Steroids
1319
METHYL STEROIDS. STUDIES ON THE SYNTHESIS OF 4-METHYL-
AND 4,4-DIMETHYL-25-HYDROXYCHOLESTAN-3-ONE DERIVATIVES
1
2,
Iwona SKIERA and Zdzisław PARYZEK *
Faculty of Chemistry, A. Mickiewicz University, 60-780 Poznań, Poland;
1
2
e-mail: skiera@amu.edu.pl, zparyzek@amu.edu.pl
Received Jan uary 25, 2007
Accepted July 24, 2007
Th e syn th etic routes to 25-h ydroxy derivatives of 4-m eth ylch olest-4-en e an d 4,4-dim eth yl-
ch olest-5-en e from m eth yl lith och olate an d m eth yl 3β-acetoxy-24-h om och ol-5-en -25-oate
(
6) h ave been in vestigated. Th e ch olest-5-en e-3β,25-diol (7), readily available from 6, was
tran sform ed in a few steps in to th e title com poun ds. It was also foun d th at brom in ation of
4-acetoxy-5β-ch olan -3-on e (1) an d of its en ol acetate followed by deh ydrobrom in ation is
2
n ot a regioselective reaction . Form ation of m ixtures of 2β-brom o-3-oxo an d 4β-brom o-3-oxo
com poun ds, wh ich gave m ixtures of 24-acetoxych ol-4-en -3-on e (4) an d 24-acetoxy-5β-ch ol-
1
-en -3-on e (5) of sim ilar polarity was observed. 4-Meth yl-25-h ydroxych olest-4-en -3-on e (14)
an d 4-m eth yl-25-h ydroxych olesta-1,4-dien -3-on e (16) are poten tial substrates for th e prepa-
ration of 4-m eth yl an alogs of vitam in D3.
Keyw ord s: 25-Hydroxy steroids; 4-Meth yl steroids; Alkylation ; Meth ylation ; Brom in ation ;
Ch olestan e.
In troduction of m eth yl groups at various position s in steroids h as been th e
subject of several in vestigation s. It is well kn own th at th e biological activity
of m odified steroids h avin g an addition al alkyl group m ay be en h an ced or
1
m odified . For exam ple som e C-2 m eth ylated 3-keton es un saturated in po-
2
sition 4 h ave h igh er activity th an th e paren t keton es . In troduction of a
m eth yl group at carbon atom C-7 in steroids resulted in com poun ds sh ow-
in g sign ifican t biological activities, especially in th e case of 7α-m eth yl iso-
3
m ers . 4α-Meth yl-5α-pregn -1-en e-3,20-dion e an d 6α-m eth ylpregn -4-en e-
3
,20-dion e derivatives h ave also been syn th esized for testin g better h or-
4
m on al activity . 4,4-Dim eth yl derivatives of an drostan e an d pregn an e h ave
been reported as well .
5
Steroids with an addition al m eth yl group in rin g A are also en coun tered
6
7
in n atural sources like sedim en ts of differen t origin , m arin e organ ism s
8
an d pollen grain s of Ambrosia elatior . A m ixture of 4α-m eth ylsterols h as
been isolated from leaves of potato plan ts Solanum tuberosum L.
9
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330
©
2007 Institute of Organic Chemistry and Biochemistry
doi:10.1135/cccc20071319

1
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Skiera, Paryzek:
1
9-Norvitam in D3 an alogs possessin g a h ydroph obic substituen t, e.g.
m eth yl or eth yl in th e C-2 position , h ave been sh own to exh ibit in creased
1
0
biological activity . In a search for com poun ds with a better th erapeutic
1
1
in dex, th e syn th esis of 4,4-dim eth yl-1α-h ydroxy-epivitam in D , 6-m eth yl-
3
1
2
13
vitam in D3 an d 4,4-dim eth ylcalciferol h as been publish ed. It h as been
proposed by Ch oliński an d Kutn er th at th e in troduction of an addition al
substituen t in to rin g A of vitam in D , for exam ple th e 4-m eth yl group, can
3
possibly ch an ge th e con form ation of th at rin g resultin g in a m odification
1
4
of in teraction of th e h orm on e with th e receptor . Th us, th e aim of our
studies was to syn th esize 25-h ydroxych olestan e derivatives alkylated in po-
sition 4.
In troduction of th e m eth yl group in to rin g A of steroids h ave been re-
ported6,15. Th e m ost frequen tly used m eth od was th e base-catalyzed
4
,5,13,16
alkylation of 3-oxosteroids
5
un saturated in position 4. Wh ile 3-oxo-
α-steroids are m eth ylated in position 2 16a or 4 15b,16b, th e 3-oxo-5β coun -
terparts react un der alkylatin g con dition s to afford m ixtures of 2- an d
-m on om eth yl as well as 2,4- an d 4,4-dim eth yl-3-oxo com poun ds1
7,18
. In
4
our plan n ed syn th esis of 4-m eth yl-25-h ydroxych olestan e derivatives, th e
readily available lith och olic acid an d 24-h om och ol-5-en -25-oic acid were
1
9
con sidered as substrates . Th us, fun ction alization of rin g A an d elon gation
of th e side ch ain of th ese substrates was required.
It h as been sh own th at brom in ation of m eth yl 3-oxo-5β-ch olan -25-oate
with iodin e m on obrom ide proceeds with th e form ation of 4β- an d
2
β-brom o-3-oxo derivatives20 an d th e exten sive m igration of brom in e from
position C-4 to C-2 h as been observed durin g a prolon ged reaction tim e.
On th e oth er h an d, good yield of 4-brom o derivatives was obtain ed wh en
various 3-oxo-5β-steroids were brom in ated in acetic acid or wh en
3
-h ydroxy-5β-steroids were treated with N-brom osuccin im ide an d h ydro-
2
1
gen brom ide . Th erefore, we expected selective brom in ation of 3-oxo-
5
β-ch olan e derivatives.
RESULTS AND DISCUSSION
In prelim in ary experim en ts oxidation of m eth yl lith och olate to th e respec-
tive 3-keton e followed by its brom in ation –deh ydrobrom in ation gave un sat-
isfactory results due to form ation of m ixtures of products. Th erefore, we
con sidered th e 3α,24-dih ydroxy-5β-ch olan e derivative as substrate. Th e
2
2
keton e 1 was treated with perch loric acid in acetic an h ydride to give en ol
acetate. Brom in ation of th e crude en ol acetate resulted in form ation of th e
m ixture of brom o keton es 2 an d 3, wh ich could n ot be effectively sepa-
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

Methyl Steroids
1321
rated. Th is was deh ydrobrom in ated with lith ium ch loride–lith ium carbon -
2
3
ate in dim eth ylform am ide to a m ixture of en on es 4
an d 5. Pure en on es
were obtain ed after crystallization an d ch rom atograph y. Th e en on e 5 was
1
13
ch aracterized by H an d C NMR, IR an d m ass spectra (see Experim en tal).
2
1
Direct brom in ation of keton e 1 (Sch em e 1) also afforded a m ixture of 4β-
an d 2β-brom o keton es 2 an d 3, wh ich were deh ydrobrom in ated as above to
1
give 4 an d 5 in th e ratio 5.6:1, assign ed from th e H NMR spectrum . It was
th erefore con cluded th at th e form ation of m ixtures of 2- an d 4-brom o
1
4
3
-keton es an d of ∆ - an d ∆ -3-keton es could n ot be avoided.
H
H
OAc
Br
(i)
+
O
O
O
H
H
H
Br
1
2
3
(ii)
O
O
H
4
5
(
(
i) 1. Ac2O, AcOEt, 72% HClO4 cat., 5 h, 2. AcONa, Br2, AcOH, 1 h;
ii) LiCl, DMF, Li2CO3, reflux, 1 h
SCHEME 1
Con sequen tly, n eith er m eth yl 3-oxo-5β-ch olan -25-oate n or 24-acetoxy-
β-ch olan -3-on e (1) were n ot furth er con sidered as substrates for efficien t
5
fun ction alization of rin g A. Th erefore, we turn ed our atten tion to h om o-
ch olan oic acid derivative19 6. Th e elon gation of th e side ch ain of th e ester 6
accom pan ied by th e in troduction of th e 25-h ydroxy group was straigh tfor-
ward an d th e double bon d in position 5 could easily be m oved in to rin g A
2
4
of th e steroid. 25-Hydroxych olesterol (7) wh ich could be syn th esized
from ester 6 in two steps in 90% yield (Fig. 1), was con sidered as an appro-
priate in term ediate in th e syn th esis of 25-h ydroxych olestan e derivatives
m eth ylated in rin g A. Com poun d 7 h as been previously reported as a key
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Skiera, Paryzek:
2
5
in term ediate in th e syn th esis of a biologically active form of vitam in D
3
2
6
an d its an alogs . In th ese syn th eses th e in troduction of th e 1α-h ydroxyl
1
9,26b,27
group was ach ieved via th e oxidation –reduction of 1-en -3-oxo
as
2
8
well as 1,4,6-trien -3-oxoch olestan e derivatives .
H
H
H
H
OH
CO2Me
2
steps
0%
9
AcO
HO
6
7
FIG. 1
Syn th esis of 25-h ydroxych olesterol (7)
3
β,25-Diacetoxych olest-5-en e29 (8) was h ydrolyzed quan titatively to
m on oacetyl derivative 9 upon m ild h ydrolysis with potassium carbon ate in
m eth an ol (Sch em e 2).
H
H
OAc
(i)
(ii)
AcO
HO
iv)
O
8
9
12
O
(
(iii)
(v)
O
O
11
10
(i) K2CO3, MeOH; (ii) PCC, CaCO3, CH2Cl2, 5 h; (iii) PCC, CaCO3, CH2Cl2, 1 h;
(iv) Al(Oi-Pr)3, toluene-cyclohexanone, reflux, 2 h; (v) oxalic acid, EtOH, reflux, 1 h
SCHEME 2
1
Th e H NMR spectrum of 9, wh ich sh owed ch aracteristic sign als at δ 1.97
an d 3.52, con firm ed th e selective h ydrolysis of th e 3-acetate group in 8.
Th e alcoh ol 9 was oxidized with pyridin ium ch loroch rom ate in m eth ylen e
ch loride to afford th e un con jugated keton e 10 in 72% yield. Th e sam e oxi-
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

Methyl Steroids
1323
dation carried out in th e presen ce of an h ydrous calcium carbon ate allowed
isolation of com poun d 10 in 77% yield. In th e prolon ged tim e reaction
(
3 h ) form ation of en on e 11 as a m ajor product or 4-en e-3,6-dion e 12 (5 h )
1
h as been observed. Com poun ds 10 an d 12 were ch aracterized by H an d
1
3
1
C NMR, IR an d m ass spectra. H NMR spectra of com poun ds 10 an d 12
3
0
were com pared with th ose of th e respective ch olestan e derivatives an d
sh owed sim ilarities with th em as expected.
Th e oxalic acid catalyzed isom erization of en on e 10 resulted in th e for-
m ation of con jugated en on e 11 in 91% yield of th e crude product; h ow-
ever, pure en on e 11 was isolated upon ch rom atograph y in 47% yield. Th e
en on e 11 was also prepared from 9 in on e step un der Oppen auer con di-
tion s in 64% yield. Com poun d 11 sh owed all ch aracteristic spectroscopic
1
13
properties (IR, H an d C NMR, MS; see Experim en tal).
Th e direct oxidation of th e diol 7 un der Oppen auer con dition s offered
altern ative route to 25-h ydroxych olest-4-en -3-on e (13), wh ich was prepared
in 86% yield (Sch em e 3). Meth ylation of th e en on e 13 with m eth yl iodide
an d potassium tert-butoxide in tert-butan ol gave a m ixture of m on o an d
H
H
OH
O
(i)
(ii)
7
+
O
O
13
14
iii)
15
(
O
16
(i) Al(Oi -Pr)3, toluene-cyclohexanone, reflux, 40 min; (ii) t-BuOK, t-BuOH, MeI, reflux, 30 min;
(iii) dioxane, DDQ, reflux, 22 h
SCHEME 3
dim eth yl derivatives 14 an d 15 of sim ilar polarity. Com poun ds 14 an d 15
were isolated in 34 an d 25% yield, respectively, after ch rom atograph y on
a silica gel colum n . Meth ylation of en on e 11 un der sim ilar con dition s re-
sulted in form ation of m on o an d dim eth yl derivatives 14 an d 15 in approx-
im ately 3:4 ratio alon g with sm all am oun t (less th an 5%) of th e substrate,
1
as estim ated from H NMR an alysis. Th e attem pts to im prove th e yield of
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1
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Skiera, Paryzek:
th e m on oalkylated derivative 14 by ch an gin g th e reaction tim e an d th e ra-
tio of reagen ts were un successful sin ce sh orter reaction tim e resulted in
h igh er recovery of th e substrate keton e 11.
In th e fin al step, deh ydrogen ation of 4-m eth yl derivative 14 with excess
2
(
,3-dich loro-5,6-dicyan o-1,4-ben zoquin on e (DDQ) in an h ydrous dioxan e
100 °C, 22 h ) gave th e expected dien on e 16 in 62% yield after ch rom atog-
raph y, alon g with th e substrate wh ich was recovered in 18% yield.
4
4
-Meth yl-1,4-dien -3-on e 16 sh owed ch aracteristic sign als of 1-H, 2-H an d
1
-CH proton s in th e H NMR spectrum . Deh ydrogen ation of en on e 15 un -
3
der sim ilar con dition s with various excesses of DDQ gave n egative results.
1
All th e n ew com poun ds were ch aracterized by H NMR, IR an d m ass spec-
tra. Th e full assign m en t of sign als in th e 13C NMR spectra of 25-h ydroxy-
ch olestan e derivatives is presen ted in Table I.
In sum m ary, we h ave developed a syn th etic route to 4-m eth yl an d
4
2
,4-dim eth yl derivatives of 25-h ydroxych olestan -3-on e 14, 15 an d 16. Th e
5-h ydroxych olest-4-en -3-on e (13), wh ich served as th e key in term ediate in
th e syn th esis, was prepared from m eth yl 3β-acetoxy-24-h om och ol-5-en -
5-oate (6) in th ree steps in 78% yield. In th e altern ative approach to com -
2
poun ds 14 an d 15, syn th etically useful n ew 25-h ydroxych olestan e deriva-
tives 9–12 were obtain ed, wh ile th e in term ediate 25-acetoxych olest-
4
-en -3-on e (11) was prepared from th e 3,25-diacetate 8 in 63% yield.
EXPERIMENTAL
Meltin g poin ts were determ in ed on a Kofler h ot-stage apparatus an d are un corrected.
IR spectra were determ in ed with an FT-IR Bruker FS 113V spectroph otom eter for solution s in
1
13
ch loroform or as KBr pellets. H an d C NMR spectra were recorded with a Varian Gem in i
00 VT spectrom eter (300 an d 75.5 MHz, respectively) operatin g in th e Fourier tran sform
3
1
m ode usin g solution s in CDCl3. H NMR ch em ical sh ifts (δ, ppm ) are given relative to tetra-
m eth ylsilan e as th e in tern al stan dard an d couplin g con stan ts (J) are given in Hz. C NMR
sh ifts were referen ced to solven t sign al at δ 77.00. Th e DEPT tech n ique was used for th e as-
sign m en t of m ultiplicity of carbon sign als in
com parison with data
1
3
1
3
C NMR spectra. Th e additivity rules an d
9
,31,32
reported for com poun ds of sim ilar structure were h elpful in sig-
n al assign m en t. Electron im pact (ion ization en ergy of 70 eV) m ass spectra were recorded
with an AMD 402 or AMD 604 spectrom eter. Solven ts were dried an d distilled accordin g to
th e stan dard procedures. Th e progress of reaction s an d purity of com poun ds were m on itored
by th in layer ch rom atograph y (TLC) usin g precoated alum in um -backed silica plates (Merck,
No. 5554). Com poun ds were visualized usin g a 10% sulfuric acid followed by h eatin g. Silica
gel 60 (Merck 70–230 m esh , No. 7734) was used for flash ch rom atograph y. Th e usual
work-up m ean s dilution of th e reaction m ixture with h exan e (dieth yl eth er or ben zen e) an d
successive wash in g of th e organ ic layer with water, 5% NaHCO3 solution , water, dryin g over
an h ydrous MgSO4 an d evaporation of th e solven t un der reduced pressure. Sam ples for ele-
m en tal an alysis were dried over ph osph orus pen toxide un der reduced pressure at 77 °C.
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

Methyl Steroids
1325
TABLE I
1
3
C NMR ch em ical sh ifts of 25-h ydroxych olestan e derivatives
Carbon
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
37.23
29.68
71.81
41.13
140.78
121.72
31.63
31.88
50.11
36.48
21.05
39.77
42.33
56.74a
24.25
28.20
56.19a
11.84
19.36
35.68
18.56
36.18
20.42
49.92
82.58
26.02
26.02
–
37.62
26.84
35.58
33.96
34.21
33.97
199.41
125.29
160.94
202.11
29.72
35.52
50.92
41.05
20.91
39.13
42.56
56.49a
23.98
28.04
55.99a
11.97
17.54
35.61
18.57
36.07
20.47
46.78
82.52
26.10
26.10
–
35.67
33.94
199.60
123.76
171.61
32.90
32.01
35.60
53.79
38.57
20.99
39.61
42.39
56.04a
24.12
28.14
55.86a
11.91
17.34
35.67
18.57
36.36
20.74
44.36
71.02
29.19b
29.32b
–
35.09
33.79
198.82
127.69
163.97
28.31
31.81
35.39
54.26
39.02
21.13
39.78
42.46
55.99a
24.19
27.80
56.06a
12.07
17.28
35.77
18.68
36.44
20.85
44.42
71.05
29.28b
29.43b
11.16
–
33.79
31.80
216.59
48.71
149.66
119.84
32.16
31.28
48.96
37.13
21.37
39.81
42.44
56.79a
24.25
28.36
56.09a
12.03
19.43
35.79
18.76
36.49
20.85
44.45
71.07
29.23b
29.45b
–
155.27
126.63
185.59
128.07
162.24
28.25
33.08
35.61
53.01
43.42
23.22
39.65
42.73
56.05a
24.41
27.83
55.54a
10.59
19.24
35.76
18.64
36.40
20.86
44.40
71.01
29.29b
29.43b
12.17
–
210.37 199.68
48.33
138.56
122.89
31.88
31.76
49.12
36.88
21.31
39.64
42.37
56.56a
24.22
28.19
56.15a
11.88
19.14
35.67
18.56
36.13
20.40
41.09
82.54
26.03
26.03
–
123.76
171.68
32.91
32.01
35.63
53.78
41.05
20.99
38.57
42.39
56.14a
24.13
28.15
55.84a
11.93
17.35
35.63
18.49
36.09
20.39
39.61
82.52
26.04
26.04
–
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
4
4
4
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
-Me
α-Me
β-Me
–
–
–
–
–
30.28
27.33
–
–
–
–
–
–
–
–
CH CO -
22.46
22.47
170.53
22.47
170.53
22.55
170.43
–
–
–
3
2
CH CO - 170.57
–
–
–
–
3
2
a,b
Th ese sign als m ay be in terch an ged.
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

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Skiera, Paryzek:
En ol-Acetylation –Brom in ation –Deh ydrobrom in ation of Keton e 1
To a solution of acetylatin g m ixture (10 m l, prepared by m ixin g acetic an h ydride (5.96 m l),
perch loric acid (0.04 m l) an d eth yl acetate (added to th e total volum e of 100 m l)), com -
poun d 1 (272 m g, 0.63 m m ol) was added an d th e m ixture was stirred for 5 h . Th e usual
work-up gave th e crude en ol acetate (280 m g, 93%) as an oil. Th is sam ple was dissolved in
a solution of sodium acetate (60 m g) in acetic acid (5 m l) an d a solution of brom in e (0.2 m l,
3
.90 m m ol) in acetic acid (5 m l) was added. Th e m ixture was stirred for 1 h , poured in to
ice-water an d th e product extracted with h exan e. Th e usual work-up gave a m ixture of 2
1
an d 3 (252 m g, 83% yield). H NMR: 0.69 s, 3 H (Me-18); 0.92 d, 3 H (Me-21, J = 6.6);
1
.08 s, 3 H (Me-19); 2.05 s, 3 H (OAc); 4.02 m , 2 H (H-24); 4.66 m , 1 H (H-C-Br); 4.98 d, 1 H
(
H-C-Br, J = 12.3).
Th e crude m ixture of brom o keton es (240 m g) was dissolved in DMF (5 m l) con tain in g
lith ium ch loride (270 m g). Lith ium carbon ate (30 m g, 0.4 m m ol) was added an d th e m ix-
ture was refluxed for 1 h . Th e usual work-up gave a residue (213 m g), wh ich was crystallized
2
3
from MeOH to give pure en on e 4 (97 m g) in 48% yield. M.p. 125–128 °C; ref. gives m .p.
23–125 °C. 1H NMR spectra are in accordan ce with ref.
23
.
1
Th e m oth er liquors were ch rom atograph ed on a silica gel colum n with ch loroform as
eluen t to give pure en on e 5. M.p. 80–85 °C (MeOH). IR (CHCl ): 2941, 2869, 2248, 1729,
3
1
1
6
5
2
6
672, 1446, 1375, 1250, 1035, 783. H NMR: 0.69 s, 3 H (Me-18); 0.93 d, 3 H (Me-21, J =
.6); 1.19 s, 3 H (Me-19); 2.05 s, 3 H (OAc); 2.77 t, 1 H (H-4α, J = 16.5); 4.02 m , 2 H (H-24);
.89 d, 1 H (H-1, J = 10.1); 6.84 d, 1 H (H-2, J = 10.1). C NMR: 12.1, 18.6, 20.9, 21.1, 22.4,
1
3
4.3, 25.3, 26.0, 26.5, 28.1, 31.9, 35.2, 35.4, 38.7, 39.1, 39.9, 41.0, 42.7, 46.3, 55.7, 56.1,
5.0 (C-24); 126.8 (C-2); 161.5 (C-1); 171 (OCOCH ); 200.6 (C-3). EI MS, m/z (%): 400 (20,
3
+
M ), 358 (1), 271 (16), 134 (33). EI HR MS for C26H40O3 calculated: 400.29854; foun d:
4
1
00.29776. For C26H40O3 (400.6) calculated: 77.95% C, 10.06% H; foun d: 78.08% C,
0.09% H.
2
5-Acetoxych olesterol (9)
To a solution of diacetate29 8 (532 m g, 1.1 m m ol) in m eth an ol (170 m l) a saturated solution
of potassium carbon ate in m eth an ol (15 m l) was added an d th e m ixture was stirred at room
tem perature for 18 h . Th e usual work-up gave com poun d 9 (485 m g, 99%, pure on TLC) as
1
an oil. IR (CHCl ): 3439, 1720, 1210, 1208. H NMR: 0.68 s, 3 H (Me-18); 0.92 d, 3 H
3
(
1
Me-21, J = 6.6); 1.01 s, 3 H (Me-19); 1.42 s, 6 H (Me-26,27); 1.97 s, 3 H (AcO-25); 3.52 m ,
H (H-3α); 5.36 bs, 1 H (H-6). For C NMR, see Table I. EI MS, m/z (%): 444 (14, M ), 384
1
3
+
(
100), 369 (33), 271 (33). EI HR MS for C29H48O3 calculated: 444.36035; foun d: 444.36134.
2
5-Acetoxych olest-5-en -3-on e (10)
A) To a solution of alcoh ol 9 (35.5 m g, 0.08 m m ol) in m eth ylen e ch loride (2 m l)
pyridin ium ch loroch rom ate (50 m g, 0.23 m m ol) was added an d th e m ixture was stirred at
room tem perature for 1 h . An h ydrous eth er (2 m l) was added an d stirrin g was con tin ued for
1
0 m in . Th e reaction m ixture was filtered th rough Florisil (60–100 m esh ) an d th e solven t
was evaporated to give en on e 10 (25.6 m g, 72%, pure on TLC). M.p. 100–105 °C (MeOH). IR
1
(
CHCl ): 3530, 3306, 2948, 2870, 1720, 1677, 1456, 1368, 1271, 1197, 1019. H NMR:
3
0
1
.71 s, 3 H (Me-18); 0.92 d, 3 H (Me-21, J = 6.6); 1.19 s, 3 H (Me-19); 1.42 s, 6 H (Me-26,27);
.97 s, 3 H (Ac-O25); 2.30 bd, 1 H (H-2, J = 13.1); 2.49 dt, 1 H (H-2, J1 = 13.5, J2 = 10.8, J3
=
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

Methyl Steroids
1327
5
.8); 2.82 dd, 1 H (H-4, J = 16.5, J2 = 1.9); 3.29 bd, 1 H (H-4, J = 16.2); 5.35 bs, 1 H (H-6).
1
1
3
+
For C NMR, see Table I. EI MS, m/z (%): 442 (10, M ), 382 (100), 298 (26), 269 (60), 229
(
(
28), 55 (43). EI HR MS for C29H46O3 calculated: 442.34470; foun d: 442.34506. For C29H46O3
442.7) calculated: 78.68% C, 10.47% H; foun d: 78.74% C, 10.52% H.
B) To a solution of com poun d 9 (94 m g, 0.22 m m ol) in m eth ylen e ch loride (5 m l) an h y-
drous calcium carbon ate (105 m g, 1.05 m m ol) was added an d th e m ixture was stirred for
5 m in . Pyridin um ch loroch rom ate (186 m g, 0.86 m m ol) was added an d stirrin g was con tin -
ued for 1 h . Work-up as above gave en on e 10 (72.1 m g, 77%).
1
2
5-Acetoxych olest-4-en e-3,6-dion e (12)
To a solution of alcoh ol 9 (108 m g, 0.25 m m ol) in m eth ylen e ch loride (5 m l) an h ydrous cal-
cium carbon ate (100 m g, 1.0 m m ol) was added an d th e m ixture was stirred for 15 m in .
Pyridin ium ch loroch rom ate (200 m g, 0.92 m m ol) was added an d stirrin g was con tin ued for
5
h . Work-up as above gave en edion e 12 (68.6 m g, 66%). M.p. 175–180 °C (MeOH–CHCl ).
3
1
IR (CHCl ): 3365, 2946, 2869, 1733, 1465, 1368, 1255. H NMR: 0.73 s, 3 H (Me-18); 0.93 d,
3
3
2
H (Me-21, J = 6.6); 1.17 s, 3 H (Me-19); 1.42 s, 6 H (Me-26,27); 1.97 s, 3 H (AcO-25);
1
3
.69 dd, 1 H (H-2, J1 = 15.5, J2 =3.7); 6.18 s, 1 H (H-4). For C NMR, see Table I. EI MS,
+
m/z (%): 396 (7, M – OAc), 382 (4), 283 (7), 137 (10), 69 (20), 43 (100). EI HR MS for
C27H41O2 calculated: 396.30283; foun d: 396.30389. For C29H44O4 (456.7) calculated:
7
6.27% C, 9.71% H; foun d: 76.48% C, 9.81% H.
5-Acetoxych olest-4-en -3-on e (11)
A) To a refluxed solution of alcoh ol 9 (50 m g, 0.11 m m ol) in toluen e (1.85 m l) an d
2
cycloh exan on e (0.25 m l, 2.41 m m ol) m ixture a solution of alum in um isopropoxide (46 m g,
.22 m m ol) in toluen e (1 m l) was added. After 1 h an addition al portion of alum in um
0
isopropoxide (36 m g, 0.18 m m ol) was added an d stirrin g was con tin ued for 1 h . Th e cooled
reaction m ixture was poured on ice/H SO (1 m l) an d th e product was extracted with eth er.
2
4
Th e usual work-up gave th e crude product (89 m g) wh ich was ch rom atograph ed on a silica
gel colum n (2 g, h exan e–eth yl acetate) to give en on e 11 (32.2 m g, 64%). M.p. 154–158 °C
1
(
MeOH–CHCl ). IR (CHCl ): 3018, 2872, 1719. H NMR: 0.70 s, 3 H (Me-18); 0.91 d, 3 H
3
3
(
1
Me-21, J = 6.6); 1.18 s, 3 H (Me-19); 1.42 s, 6 H (Me-26,27); 1.97 s, 3 H (OAc-25); 5.72 s,
H (H-4). For C NMR, see Table I. EI MS, m/z (%): 442 (2.8, M ), 382 (100), 340 (18), 298
1
3
+
(
28), 269 (45), 124 (59). EI HR MS for C27H43O calculated: 382.32358; foun d: 382.32367. For
C29H46O3 (442.7) calculated: 78.68% C, 10.47% H; foun d: 78.88% C, 10.44% H.
B) To a solution of en on e 10 (120 m g, 0.27 m m ol) in eth an ol (95%, 7 m l) oxalic acid
(
30.2 m g, 0.33 m m ol) was added an d th e m ixture was stirred at reflux for 1 h . After coolin g
th e product was extracted with eth er. Th e usual work-up gave th e crude product (109 m g,
1%), wh ich was ch rom atograph ed on a silica gel colum n (4 g, h exan e–eth yl acetate) to give
9
1
en on e 11 (50 m g, 47%). H NMR spectrum was iden tical with th at of sam ple described
above.
2
5-Hydroxych olest-4-en -3-on e (13)
To a refluxin g solution of diol 7 (1.47 g, 3.7 m m ol) in toluen e (30 m l) an d cycloh exan on e
(
5 m l, 48.2 m m ol) m ixture a solution of alum in um isopropoxide (800 m g, 3.8 m m ol) in tol-
uen e (15 m l) was added dropwise durin g 30 m in an d th e m ixture was refluxed for addition al
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

1
328
Skiera, Paryzek:
4
0 m in . Th e cooled reaction m ixture was poured on ice/H SO an d th e product was ex-
2
4
tracted with h exan e–eth er. Th e usual work-up gave crude product (1.8 g), wh ich was
ch rom atograph ed on a silica gel colum n (10 g, ben zen e) to give pure 13 (1.2 g, 86%). M.p.
1
50–152 °C (MeOH–h exan e); ref.21 gives m .p. 147–148 °C. IR (KBr): 3470, 1657, 1610.
1
33
H NMR spectrum in agreem en t with ref.
Meth ylation of 25-h ydroxych olest-4-en -3-on e (13)
To a boilin g solution of potassium tert-butoxide in tert-butan ol (potassium (230 m g, 5.9 m m ol)
an d t-BuOH (40 m l)) a solution of en on e 13 (497 m g, 1.2 m m ol) in tert-butan ol (25 m l) was
added dropwise over 1 h . Th e solution of m eth yl iodide (3.8 m l, 61.04 m m ol) in tert-butan ol
(
18 m l) was added dropwise over 1.5 h an d th e resultin g m ixture was refluxed for 30 m in .
After coolin g, th e reaction m ixture was acidified with 1 M HCl an d th e solven t was evapo-
rated. Th e crude product was extracted with ben zen e, th e organ ic layer was wash ed with
NaHSO , brin e an d water, dried with MgSO an d evaporated to give crude product (505 m g)
3
4
wh ich was ch rom atograph ed on dry silica gel colum n (3 g, ben zen e) to give 4-m eth yl-
2
5
5-h ydroxych olest-4-en -3-on e 14 (168 m g, 34%) an d 4,4-dim eth yl-25-h ydroxych olest-
-en -3-on e 15 (130 m g, 25%). Addition ally, oth er fraction s afforded sligh tly im pure com -
poun d 14 (33 m g) an d 15 (46 m g).
Compound 14: M.p. 151–154 °C (MeOH–CHCl ). IR (KBr): 3567, 2964, 1656, 1601, 1468,
3
1
1
376, 1332, 1310, 1246, 1143, 1027, 918. H NMR: 0.71 s, 3 H (Me-18); 0.92 d, 3 H (Me-21,
J = 6.5); 1.16 s, 3 H (Me-19); 1.21 s, 6 H (Me-26,27); 1.77 d, 3 H (Me-4, J = 1.1); 2.74 dt, 1 H
1
3
+
(
H-6, J1 = 14.8, J2 = 3.3). For C NMR, see Table I. EI MS, m/z (%): 414 (6.5, M ), 396 (40),
3
4
1
81 (11), 283 (21), 138 (81), 59 (100). EI HR MS for C28H46O2 calculated: 414.34979; foun d:
14.34699. For C29H46O2 (414.7) calculated: 81.10% C, 11.18% H; foun d: 81.19% C,
1.08% H.
Compound 15: M.p. 210–215 °C (MeOH–CHCl ). IR (KBr): 3567, 2954, 2867, 1700, 1655,
3
1
1
0
2
460, 1376, 1254, 1136, 1029, 915. H NMR: 0.67 s, 3 H (Me-18); 0.85 s, 3 H (Me-19);
.94 d, 3 H (Me-21, J = 6.3); 1.22 s, 6 H (Me-26,27); 1.23 s, 6 H (Me-4α an d Me-4β);
1
3
.39–2.62 m , 2 H (H-2); 5.56 m , 1 H (H-6). For C NMR, see Table I. EI MS, m/z (%): 428
+
(
23, M ), 410 (17), 395 (12), 123 (100). EI HR MS for C29H48O2 calculated: 428.36542;
foun d: 428.3637. For C29H48O2 (428.7) calculated: 81.25% C, 11.29% H; foun d: 81.20% C,
1
1.31% H.
Meth ylation of 25-Acetoxych olest-4-en -3-on e (11)
To a boilin g solution of potassium tert-butoxide in tert-butan ol (potassium (35 m g, 0.90 m m ol)
an d t-BuOH (6.3 m l)) a solution of en on e 11 (74.6 m g, 0.16 m m ol) in tert-butan ol (3.5 m l)
was added dropwise an d th e m ixture was refluxed for 1 h . Th e solution of m eth yl iodide
(
0.56 m l, 8.9 m m ol) in tert-butan ol (6.3 m l) was added dropwise over 1 h . After 30 m in th e
reaction m ixture was cooled to room tem perature, diluted HCl was added to adjust pH 6
an d th e solven t was evaporated un der reduced pressure. Eth er was added an d th e organ ic
layer was wash ed with NaHSO , water an d dried with MgSO . Evaporation of th e solven t
3
4
gave th e crude product (69.6 m g, 90%) as a m ixture of com poun ds 14 an d 15 in 3:4 ratio
1
an d som e traces of th e substrate 11 (estim ated from H NMR spectrum by in tegration of sig-
n als at δ 2.74 an d 2.50).
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

Methyl Steroids
-Meth yl-25-h ydroxych olesta-1,4-dien -3-on e (16)
To a solution of en on e 14 (71 m g, 0.17 m m ol) in an h ydrous dioxan e (10 m l) 2,3-dich loro-
1329
4
5
,6-dicyan o-1,4-ben zoquin on e (200 m g, 0.88 m m ol) was added an d th e m ixture was stirred
at reflux for 22 h . After coolin g th e solution was filtered th rough colum n of Al O (n eutral,
2
3
1
g) wh ich was eluted with ben zen e. Th e crude product (66 m g, 92%) was ch rom atograph ed
on a silica gel colum n (1.5 g, CHCl –h exan e 40:1) to give en edion e 16 (44.5 m g, 62%) as an
3
oil an d th e substrate 14 (12.5 m g, 18%).
Compound 16: IR (CHCl ): 3023, 3016, 2941, 1657, 1618, 1223. 1H NMR: 0.74 s, 3 H
3
(
3
Me-18); 0.92 d, 3 H (Me-21, J = 6.6); 1.21 s, 6 H (Me- 26,27); 1.25 s, 3 H (Me-19); 1.91 s,
H (Me-4); 2.85–2.26 m , 1 H (H-6); 6.25 d, 1 H (H-2, J = 10.1); 7.03 d, 1 H (H-1, J = 10.1).
1
3
+
For C NMR, see Table I. EI MS, m/z (%): 412 (11, M ), 394 (45), 379 (6), 338 (13), 283 (18),
1
36 (87), 82 (97), 55 (100). EI HR MS for C28H44O2 calculated: 412.33414; foun d: 412.33621.
We thank Prof. A. Kutner for generous gift of methyl 3β-acetoxy-24-homochol-5-en-25-oate.
REFERENCES
1
2
. Zhu G.-D., Okamura W. H.: Chem. Rev. 1995, 95, 1877.
. Hogg J. A., Lincoln F. H., Jackson R. W., Schneider W. P.: J. Am. Chem. Soc. 1955, 77,
6
401.
3
4
5
. Zheng Y., Li Y.: J. Org. Chem. 2003, 68, 1603; and references therein.
. Burn D., Petrow V.: J. Chem. Soc. 1962, 1223.
. Adams W. J., Patel D. K., Petrow V., Stuart-Webb I. A., Sturgeon B.: J. Chem. Soc. 1956,
4
490.
. Schaeffer P., Fache-Dany F., Trifilieff S., Trendel J. M., Albrecht P.: Tetrahedron 1994, 50,
2633.
6
1
7. Vanderah D. J., Djerassi C.: Tetrahedron Lett. 1977, 18, 683.
8. Ohmoto T., Ikeda K., Chiba T.: Chem. Pharm. Bull. 1982, 30, 2780.
9. Schreiber K., Osske G.: Tetrahedron 1964, 20, 2575.
1
0. Shimizu M., Iwasaki Y., Shimazaki M., Amano Y., Yamamoto K., Reischl W., Yamada S.:
Bioorg. Med. Chem. Lett. 2005, 15, 1451.
1
1
1
1
1
1. Berman E., Friedman N., Mazur Y., Sheves M.: J. Am. Chem. Soc. 1978, 100, 5626.
2. Garcia A. M., Mascarenas J. L., Castedo L., Mouriñ o A.: J. Org. Chem. 1997, 62, 6353.
3. Cooley G., Ellis B., Petrow V.: J. Chem. Soc. 1955, 2998.
4. Choliński J., Kutner A.: Polish J. Chem. 1997, 71, 1321.
5. a) Overnell J., Whitehurst J. S.: J. Chem. Soc. C 1971, 378; b) Sucrow W., Littmann W.,
Radüchel B.: Chem. Ber. 1977, 110, 1523.
1
6. a) Mazur Y., Sondheimer F.: J. Am. Chem. Soc. 1958, 80, 5220; b) Mazur Y., Sondheimer F.:
J. Am. Chem. Soc. 1958, 6296; c) Atwater N. W.: J. Am. Chem. Soc. 1960, 82, 2847.
7. Schlatter H.-R., Lüthy C., Graf W.: Helv. Chim. Acta 1974, 57, 1044.
8. Aranda G., Fetizon M., Tayeb N.: Tetrahedron 1987, 43, 4147.
1
1
1
9. Semmler E. J., Holick M. F., Schnoes H. K., DeLuca H. F.: Tetrahedron Lett. 1972, 13,
4
147.
2
2
0. Yanuka Y., Halperin G.: J. Org. Chem. 1974, 39, 3047.
1. Ochi K., Matsunaga I., Shindo M., Kaneko C.: Chem. Pharm. Bull. 1979, 27, 252.
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330

1
330
Skiera, Paryzek:
2
2
2
2
2. Hayakawa S., Kanematsu Y., Fujiwara T.: Biochem. J. 1969, 115, 249.
3. Manley R. P., Curry K. W., Deno N. C., Meyer M. D.: J. Org. Chem. 1980, 45, 4385.
4. Ikan R., Markus A., Goldschmidt Z.: J. Chem. Soc., Perkin Trans. 1 1972, 2423.
5. Morisaki M., Rubio-Lightbourn J., Ikekawa N., Takeshita T.: Chem. Pharm. Bull. 1973, 21,
2
568.
2
2
2
6. a) Partridge J. J., Faber S., Uskoković M. R.: Helv. Chim. Acta 1974, 57, 764; b) Narwid T. A.,
Blount J. F., Iacobelli J. A., Uskoković M. R.: Helv. Chim. Acta 1974, 57, 781.
7. Morisaki M., Saika A., Bannai K., Sawamura M., Rubio-Lightbourn J., Ikekawa N.: Chem.
Pharm. Bull. 1975, 23, 3272.
8. Barton D. H. R., Hesse R. H., Pechet M. M., Rizzardo E.: J. Chem. Soc., Chem. Commun.
1
974, 203.
2
3
3
9. van Lier J. E., Smith L. L.: J. Org. Chem. 1970, 35, 2627.
0. Błaszczyk K., Paryzek Z.: Synth. Commun. 1994, 24, 3255.
1. Wilson W. K., Swaminathan S., Pinkerton F. D., Gerst N., Schroepfer G. J.: Steroids 1994,
5
9, 310.
3
2. a) Römer J., Scheller D., Grossmann G.: Magn. Reson. Chem. 1987, 25, 135; b) Nangia A.,
Anthony A.: Synth. Commun. 1996, 26, 225; c) Meskó E., Schneider G., Dombi G., Zeigan D.:
Magn. Reson. Chem. 1994, 32, 565; d) Blunt J. W., Stothers J. B.: Org. Magn. Reson. 1977,
9
, 439.
33. Righi G., Bovicelli P., Sperandio A.: Tetrahedron 2000, 56, 1733.
Collect. Czech. Chem. Commun. 2007, Vol. 72, No. 10, pp. 1319–1330