Minor and trace sterols in marine invertebrates XVII. 1 (24R)-24,26-dimethylcholesta-5,26-dien-3β-01, a new sterol from the sponge Petrosia ficiformis

2636

707 MINOR AND TRACE STEROLS IN MARIME INVERTEBRATES

XVII.'

(~!4R~-Z4,26-D~M~THYLCHOLES~A-5,26-DIE~~-3~-~1, A NEW STEROL FROM THE SPONGE PETROSIA FICIFORMIS. M. Wahid Khalil and Carl Djerassi* Department of Chemistry, Stanford University Stanford, California 94305 and D. Sica Istituto di Chimica Organica e Biologica, Via Mezzocannone 16 Naples , Italy

Received z-24-80

ABSTRACT

IMore than thirty monohydroxy sterols were detected in the marine sponge Petrosia ficiformis, ranging from the ubiquitous 24-norcholestasterol, 24-propylidenecholesterol. A new 5,22-gdien-38-01 to the C minor sterol was isolate 8 and shown by spectral analysis and comparison with (a synthetic sample to be (24R)-24,26-dimethylcholesta-5,26-dien-38k301 [26(29)-dehydroaplysterol] (12). INTRODUCTION The discovery of sterols with novel side chains from marine invertebrates is proceeding at a remarkable rate (2,3,4), and members of the Porifera (sponges} have contributed many new sterols to this accumulation of marine natural products. cyclopropane-containing

Recently, petrosterol (l3_),a novel

sterol , was isolated and characterized from

Petrosia ficiformis (5) and from Halichondria, a Pacific sponge (6). --__~ As part of our continuing research on minor and trace sterols from marine invertebrates, we reexamined the free sterol fraction of p. ficiformis by the recently described analytical methods (7), with the ~I_ hope of detecting other novel sterols which might function as biosyn-

Volume 35,,Number 6'

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?l?IIROLDCI

June, 1.980

thetic intermediates for petrosterol, or which by themselves possess uniquely interesting structures. -RESULTS AND DISCUSSION GLC analysis on 3% OV-17 of the free sterol fraction indicated at least 10 sterols present in p. ficiformis, while capillary GC (8) suggested at least 18 sterols with petrosterol (13) the major sterol. Since these techniques only offered a guide to the sterol composition of the mixture, it was necessary to fractionate the mixture further. Fractionation of the acetates by argentic thin layer chromatography (9) produced seven major bands (see Experimental).

The most polar band

contained 4 major components with 24-methylene cholesterol (7_)as the only readily identifiable sterol.

Further Ag+/TLC and HPLC of this band

produced a new C29 sterol (1.3% of total sterol mixture) together with two other unknown sterols whose structure elucidation is discussed elsewhere (lo).

The retention behavior of the new C29 sterol (R T. 1.7#,on

3% OV-17) was similar to that of authentic samples of 24(28)-dehydroaplysterol and 25-dehydroaplysterol and has now been shown to be the hitherto undes~ribed 26(29)-dehydroaplysterol

(121 [(24~)-24,26-dimethyl-

cholesta-5,26-dien-3~-ol]. The mass spectrum of -72 showed peaks at -m/z 394, 379, 271, 255, and 213, suggesting a normal A5-3!3-hydroxy sterol (11).

Significantly, sterol

m/z 314 and 328, suggesting it does not contain adouble -12 lacked ions at -bond at C-24 or 25 (12).

The 360 MHz 'H NMR spectrum (CDC13) of JZ_ (ace-

tate) showed 6 methyl signals: 0.677 (s, C-18); 0.797 (d, 3H, C-28);0.905

S

709

TEIROIDS

(d, 3H, C-21); 0.933 (d, 3H, C-27); 1.019 (s, 3H, C-19); and 2.032 (s, 3H, COCH3).

A pair of doublets at 4.96 and 4.93 is assigned (13) to a

terminal methylene group (C-29, 2H), and irradiation experiments demonstrate that these hydrogens are coupled to the C-26 vinylic proton at 5.75.

The *5-3~-OH moiety is also suggested by signals at 5.38 (C-6H)

and 4.6 (3a-H of acetate).

Finally, irradiation of the allylic C-25

hydrogen collapses the C-27 doublet at 0.933 to a singlet.

Comparison of

the 360 MHz 'H NMR spectrum with that of a sample obtained in our laboratory (14) by acid-catalyzed ring opening of petrosterol (13) as well as coinjection on GLC, showed that these two compounds were identical. The sitereochemistry at C-24 was assigned as (241) similar to that (5) in petrosterol and aplysterol. HPLC analysis of p. ficiformis sterols. The sterol mixture of p. ficiformis was also fractionated by HPLC on a What:man M9 preparative ODS-2 (reverse phase) column and eluted with absolute methanol.

Eight main fractions were collected, and GC and com-

bined GC/MS analyses of these fractions revealed the complexity of this sterol mixture. c26 sterols. Two C26 sterols were characterized, 24-norcholesta-5,22-dien-36-01 (2) and its nuclear saturated analog lJ, both in trace amounts.

Sterol 3,

whose Ibiosynthetic origin has not yet been established, is present in almost all of the marine invertebrate phyla examined (4). st(arols &27----' Cholesterol (5) which is usually a major sterol in most organisms is present in only trace amounts in p. ficiformis (~0.5%).

A saturated C27

sterol (SRN lo), R.T.0.82 and Mf 388, and different from chofestanol , is found in minor amounts. (2).

It may be the saturated analog of occelasterol

Sterol 3 and 22-dehydrocholesterol

(4) contribute only 2.4% to the

total sterol mixture,

C&

sterols. Another colon

marine sterol isolated

me~hy~cholesta-5,22-dien-3~-o~ mixture. m

from j)_. ficiformis is 24-

(g), which accounts for 6% of the total

360 MHz 'H NMR analysis suggests that 5 is a mixture of the

and S_ epimers with the 24s epimer predominating.

Of some interest

is the detection of 24~-methyfcholesta-7,22-dien-3~-ol

(26) in trace -

amounts - the only A' sterol detected during our analysis.

However,

this sterol has been reported in other marine invertebrata phyla, echi~od~~s

e.g,

(15).

Of significance is the isolation of two C28 ~y&lopropane sterols, SRN 15,16 (Table I) in _P_.ficiformis, which are presently under investigation.

An uncharacterized C2S cyclopropane-containing

sterol has also

been detected in a Halichondria sp. (S), which is the other known source of petrosterol (13). -

fZz9 sterols. These make up

the bulk of the sterols

petrosterol (13) the major -

sterol (60%).

in fl. ficiformis, with

In addition to the new C2g

sterol 12, (24RS).-24-ethylcholesta-5,22-dien-38-o1 (9J, fucosterol (l0), isofucosterol (ll), and sitosterol (VI_),are also present. of 5a-isofucostanol

Trace amounts

(23) were detected, and this sterol was recently -

shown (16) to be the major sterol in a deep sea jellyfish,

Sterols -24

and 25_, the 5c+saturated analogs of 2 and 14_, were detected by mass spec-

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711

T30ROTD8

trometry of the free sterols obtained from the most nonpolar band on A&TLC. &

sterols. Two C3O sterols were detected by mass spectrometry after fraction-

ation and enrichment of the polar C-5 band (see Experimental).

One of

these sterols has been shown to be (242)-24-n-propylidenecholesterol (l&), on the basis of its mass spectrum and coinjection on 3% OV-17 (R.T.2.14).

The other C30 sterol, R.T. 2.00, has a mass spectrum similar

to __ 16 and is formulated as the (24&) isomer -15.

It has a similar re-

tention time when coinjected with an authentic sample of -15 isolated recently in our laboratory (17). The occurrence of both 24E- and L-isomers in a scallop has already been suggested (18) although NMR data were not obtained for the 24i isomer.

CONCLUSIONS The free sterol fraction of P_. ficiformis has been shown to contain a complex mixture of more than 30 marine sterols; C29 sterols predominate, but trace amounts of C22, C26, C27, C28 and C30 sterols are present. Petrosterol (13) is the major sterol, and is of great biosynthetic interest because it possesses a unique 26,27-cyclopropane

group in the side chain.

The precise function of petrosterol in P_. ficiformis is unknown and whether it is intricately involved in membrane stability or possesses biochemical functions remains to be established.

The presently described

isolation of (24lJ)-24,26-dimethylcholesta-5,26-dien-3c-o1 [26(29)-dehydroaplysterol]

(12) is interesting and one can speculate on its origin, e.g.,

whether it is formed from petrosterol (13) _- or vice versa.

If -12 is

S

712

formed from _ll- analogous

TEIROXDCl

to the acid-catalyzed

opening

et al. (14) - then it can be suggested Tarchini, -I

intermediates

the cyclopropane

alkylated

sterol mixture.

bination of separation methods has been successfully ize nearly 50 sterols from the gorgonians Plexaura homoalla

(7), although

single methods

If a comprehensive

analysis

of total sterols are available

used to characterand

such as capillary containing

is required,

of Popov, et al. (7) are to be recommended.

However,

is

A com-

Pseudoplexaura'porosa

have been used to fractionate a marine sediment (19).

from marine

(2,3,4) clearly indicates that no single technique

adequate for complete analysis of any complex

mixture

may be

sterols.

The large number of sterols isolated and characterized invertebrates

ring;

(3) that cyclopropanes

in the formation of unsaturated

by

that p. ficiformis

possesses the enzyme system capable of cleaving this would lend support to the suggestion

reported

GC/MS

a complex

then the methods

if small amounts

(%5-10 mg), then we suggest

that the

sample be analyzed as follows: (a) rapid screening of the total free sterol mixture

by combined GC/MS

on packed or capillary columns; (b) fractionation

of the sterol acetates by AgN03

TLC, followed by combined GC/MS analysis

impregnated

silica gel

of the free sterols or ace-

tates of each band; (c) isolation by HPLC of any new sterol(s) (b), and characterization When desirable,

indicated

by high resolution

by either

(a) or

NMR.

steps (b) and (c) can be readily interchanged.

shortened isolation protocol can make possible

the structure

of a new sterol with less than 100 ug of pure sample,

This

elucidation

and can be per-

S

TEIRQXDS

713

formed in a relatively short time. EXPERIMENTAL General -__ Analytical GLC was carried out with a Hewlett-Packard 402 A chromatograpih using 3% OV-17 on 100/120 GCQ (Applied Sci. Inc.) in a 4mm I.D. x 1.&n 'U' shaped glass column using a flame ionization detector. Oven temperature was 260", and the carrier gas was helium, flow rate 80 ml/min. Preparative HPLC was performed using a Haskel model 28303 pump, and a Waters Associates dual cell refractometer as described earlier (7). For enrichment and separation either a Whatman Partisil M9 lo/50 ODS-2 column (50 cm x 0.9 cm I.D.) pressure 1000 psi, flow rate 5 ml/min, mobile phase absolute methanol, or a Waters or Bondapak C column (250mm x 4.6mn I.D., pressure 725 psi, flow rate 2 mllmin, mobi*'1@phase methanol/ wate'r 95:5) was used. Low resolution GC/MS was performed on a Varian MAT-44 GC/MS system using a 2.7mm I.D. x 2M spiral glass column, containing 3% OV-17 on GCQ, and oven temperature of 260". High resolution GC/MS was performed on a Varian MAT 711 double focussing spectrometer under conditions previously described (7). 100,MHz NMR spectra (CDC13) were run on a HA-100 NMR spectrometer (Varian Assoc.) equipped with a NTCFT-1180 computer, and 360 MHZ NMR spectra were obtained on a Bruker HX 360 spectrometer in either CDC13 or C6D6 with TMS as internal referenc:e. Chemical shifts are in 6, (ppm). ARGENTATION TLC CHROMATOGRAPHY _I_ Sterol acetates formed by acetylation with pyridine-acetic anhydride were chromatographed on silica gel HF silica gel (E. Merck) plates 600 1-I thick, developed with ei. ?m3@ xane-benzene (9) or hexanetoluene mixtures; 30-40 mg were applied to each plate, and after removal of solvent(s), bands were detected by long range U.V. light. Sterols were recovered from each band with diethyl ether. Four "bands" were eluted, A-D; band A contained sterols l8_, 20, 22_, 24 and 2J; band B contained sterols 3, S, 2, 13 and 2, and band D contained sterols 7 and 12, as well as two unknown sterols, SRN 14 and 22 (Table I). Band C whzh is made up of sterols intermediate in polarity between cholesterol (5) and 24-methylenecholesterol (7) was subdivided by further Ag' ion chromatography into C-l, C-2, C-3, C-z and C-5. C-l was the same as B, while C-2 contained 21 and 5 (major); C-3 consisted mainly of 2, 3, 3 and 6; C-4 contained 2, rand 4, SRN 26 (minor), lJ, lJ, l5_, E; and C-5 was made up of 2, lo, ll_, -15 and -16. Isolation of (24R)-24,26-dimethycholesta-5,26-dien-38-o1 12 from band D. Band D containing sterols 7, 12 and unknown sterols GN 14 and 22 _ was rechromatographed on AgNO Impregnated silica gel TLC plates developed three times with hexane-tolueJe (1:l). Two bands were obtained: D-l contained 12 and D-2 was a mixture of & SRN 14, and 22. D-2 was purified further by HPLC into pure SRN 22 (M 412) and an equal mixture of 2 and

714

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TXlRO+DS

SRN 14 (M+398). Attempts to separate or enrich 1 from SRN 14 using the HPLC solvent system described was unsuccessful, although structural assignment was possible by 360 MitiZ H' NMR spectroscopic analysis by subtracting the spectrum of authentic 7_ from that of the mixture. 24-Norchoiesta-5,22-dien-3lvol (2): 'H NMR (CDCl 700 MHz) 0.690 (s, C l8I) (5 Y4U (d bH C %b d Z/f 1.009 (s 3H ?h) 1.006 (d 3H Cs21): 3:50 (m+'lH,'C-3), ;fn9 (rn,'2H C-22/!!3) 'and 5.$ (m, lH,'C-6; MS: 370 (70, M , C H Of, 355 (73, if-CH ), 352 (23, M -H,O), 300 (421, 271 (31), 255 (66~~62~~ (19) and 97 (100)3 22-trans-Cholesta-5,22-dien-3B-ol (4): 0.674 (s, 3H, C-18), 0.932 (d, U Y4Y (s,TC-19), 1.12 (d, 3H, J=6.36, C-21), 3.40 (r$,lH, C-3), 5I3 (m, ZH, C-22/23), and 5.25 (m, ‘1H, C-6). MS: 384 (99, M , C H O), 369 (18, M -CH ), 366 (27, M -HZ@, 300 (80), 271 (44), 255 ~~8~~ 213 (24), and ll13(68).

~KYT,7TZb,‘Z/j

(24RS)-24-Methylcho?esta-5,22-dien-38-o1 (6): 0.076 (s, 3H, C-18), 0.923 (d bH J=626, Hz, C-27/‘28J;--@:9~7-(-~: J= 6.75 Hz, C-26), 0.951 (s, 3H: C-;9), 1.015 (d, 3H, 5=6.85 Hz, C-21), 3.38 (m, IH, C-31, 5.26 (m, 2H, C-22/23), and 5.36 {m, lH, C-6). The mixture lontained mainly the 2$S_ epimer. MS: 328 (M , 82, C H 0), 3.83 (6, M -CH ), 380 (12, M -H O), 365 (6, M -CH -H 01, 3@ %,, 337 (lo), 314 (3), 300 (43), 271 (43): 255 (561, 231 (63, sl3 (16) and 69 (100). 24-Methylenecholesterol (L) (acetate): 0.648 (s, 3H, C-18), 0.925 (s, XT, C-19) I UIZ (d JH J=7.09 Hz, C-21), 1.080 (d, 3H, 3~6.85 Hz, C-26/27),'1.&6 fd,'3H,'J=6.77 Hz, C-26/27), 4.8O~~m, lH, C-3), 4.90 (s, 3tj, C-281, and 5.38,(m, lH, C-6). MS: 398 (37, M , C H O), 383 (11, M -CH ), 380 (13, M -H 0). 315 (231, 314 (100 M~L~ff~~~~~ 299 (32), 296 (201, 281 (191, 27? (441, 255 (lo), 253 (iO), and 213 i231. ~24RS)~24-Methy?cholest-~-en-3~-ol (8): MS: 400 (100, M+-C H 0), 385 (-2-l M CH ) .M“ (Sb PI H Uj,m49), 289 (461, 273 (2&4%5 (26), 231'(21j, 25; (26), ar;d 2;3'(4). ~~4RS~-24-Ethylcholest-~,2Z-en-3~-ol (9): MS: 472 (23, M+ C2 H 80), 397 lb M CR ) 3Y4 (I/ M H U) 314 (437, 300 (151, 27-i (l&i), P5ff (J9), 23i (7i, 2nd 213 (22;. - 2 ’ Fucosterol (10) (acetate) (CDCl ): 0.686 (s, 3H, C-18), 0.979 (d, SW, J b 5/ H CL76 and 27), 0.988 td, 3H, Jz6.1 Hz C-21) 2.20 (septet li,.C-25;: 4.60 (m, lH, C-3) 5.18 (q, 1H, C-28j, +nd g.36 (m, fH, $16). MS: (free sterol) 412 (18, Mf, C2 H 801, 397 (4, M -CH ), 394 ;,d ;13H20), q;;,(lOO, McLafferty), 299 (23), $98 (151, 281 (21), 225 (6),

Isofucosterol (11) (acetate) (CDCl ): 0.682 (s, 3H, C-18), 0.947 (d, 3H, J b 4/ H C 21) 0.976 (d 6H J=$.93 Hz C-26 and 27) 1 020 (s 3H CflQ), 2!;3 Tsepiet, lH, C125): 4.60 (m, :H, C-3), 5 12'(q[ lH, Cr28): and 5.36 (m, lH, C-61. MS: (free sterol) 412 (13, Mf, C2QH4S0), 314

S

TIEIECOXDIP

715

(100, C22H340, McLafferty; MS of ll_ is very similar to _lO above. ,26-Dimethylcholesta-5,26-dien-36-01 (12): m.p. (acetate) illN?lR (3bO I;IAzofm]. 0 b// c-S= C-18), 0,797 (d, 3H, 5~6.67, C-28), 0.905 (d, 3H, J=6.50 I&, C-21), 0.933 (d, 3H, J=6.84 Hz, C-27, after decoupling singlet at 0.930), 1.019 (s, 3H, C-19), 2.032 (s, 3H, CDCH ), 4.60 (m, lH, C-3), 4.97 and 4.93 (s, 2H, C-29), 5.38 (m, lH, C-6),+x% (m, lH, C-26). MS (free sterol): 412 (M 100, C29H ,O,, 397 (9, M -CH3, C 2 H 01, 394 (8, M -H 0, C H ), 314 (i5, C H Of, 30J (12 C H 1, 27f f2@? ClgH270), 255 (8, CJ~~2~~, 231 (4, CJ6~~3~~, and 213'(2ij; ~~6H2J~Petrosterol (13) (CDCl ): 0.02-0.18 (complex m, 2H, C-26), 0.40-0.50 (m, ZH, C-24, C-25), 0.888 (d, 3H, J=6.69 Hz, -@X--nr, L- Z/),0.55-0.25 C-28), 0.920 (d, 3H, J=6.42 Hz, C-21), 1.006 (d, 3H, J=6.5 Hz), 1.099 (s, 3H, C-191, 3.60 (m, $H, C-3), and 5.38+(m, JH, C-6). MS:+412 (94, M , C H D), 397 (14, M -CH ), 394 (28, M -H 0), 379 (10, M -CH -H 0), 370 (iiq,"fs52(31, 337 (3), 328 (2)s 327 (12),2314 (23), 301 (21): 231 (66), 255 (ll), 231 (J2), and 213 (19). 24(RS)-24-Ethylcholest-5-en-3B-o1 (14): 'H NMR 0.667 (3H, s, C-18), 0.800 Tnr;-n/.0 Hz, C--27fTm,-, J=7.3 Hz, C-26), 0.843 (3H, t, J=7.5 Hz, C-29}, 0.910 {3H; d, J=6.3 Hz, C-211, 0.297 (3H, s, C-19), 3.53 ($H, m, 3 -H), 5.35+(lH, m, 6-H). MS; 414 (100, M , C HsOO), 399 (22, M -CH ), 396 (45, M -H 0), 381 (21, M -CH -H20), 329 @), 303 (291, 273 (?S), 255 (19), 237 (J3f, and 213 (223. (242)-24-tropylidenecholes$-5-en-38-01 (16): MS: 426 (12, M", C H 0), -3 M CH J 4U8 (2 M R 0) 314 m McLafferty), 299 (lay,%!96 (18),, i81 717?,'271 (9): 255 t4): 229 (11): and 213 (9). (24E)-24-Propylidenecholest-5-e~-3fi-o1 %7%Z--ot lb --

(15): The MS of 1% is very similar

ACKNOWLEDGEMENTS Financial support to Stanford University was provided by NIH grants GM06840 and AM-04257. We acknowledge Annemarie Wegmann~s mass spectral measurements and Dr. Lois Durham's help with the 360 MHz NMR spectra, as well as access to the Stanford 360 MHz NMR facility (NSF grant GP-23633 and NIH grant RR-0711). M.W.K. was the recipient of a NATO research grant SRG-10.

716

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TIIROXDS

REFERENCES -___-_

1. 2. 3. 4. 5.

6. 7. 8.

9. 10.

11. 12. 13.

14.

15. 16. 17. 18. 19.

For Part XVI, see Bohlin, L., Gehrken, H. P, Scheuer, P. J., and Djerassi, C., STEROIDS, in press. Schmitz, F. J., in "Marine Natural Products", Vol. 1, Scheuer, P. J., Ed., Academic Press, New York, N.Y., 1978, pp. 241-297. Djerassi, C., Theobald, N., Kokke, W. C. M. C., Pak, C. S., and Carlson, R. M. K., PURE & APPL. CHEM., 51, 1815 (1979). Goad, L. J., in "Marine Natural Products", Vol. 1, Scheuer, P. J., Ed., Academic Press, New York, N-Y., 1978, pp. 75-171. Sica, D. and Zollo, F., TETRAHEDRON LETT., 837 (1978) and Mattia, C. A., Mazzarella, L., Puliti, R., Sica, D., and Zollo, F., TETRAHEDRON LETT., 3953 (1978). Ravi, B. N., Kokke, W. C. M. C., Delseth, C., and Djerassi, C., TETRAHEDRON LETT., 4379 (1978). Popov, s., Carlson, R. M. K., Wegmann, A., and Djerassi, C., STEROIDS, 28, 699 (1976). Free sterols analyzed on a 15 m glass capillary column coated with SE-52 (at 240°C); we wish to thank Ms. Annemarie Wegmann for performing this analysis. Idler, D. R. and Safe, L. M., STEROIDS, l9_, 315 (1972). Khalil. M. W., Durham, L., Djerassi, C., and Sica, D., J. AMER. CHEIM. sot., 102, 2133 (1980); Karpf, M. and Djerassi, C., TETRAHEDRON LETT., in press. Zaretskii, Z. V., in "Mass Spectrometry of Steroids", Israel Universities Press, Jerusalem, 1976, p. 96. Massey, I. and Djerassi, C., J. ORG. CHEM., 44, 2448 (1979). Jackman, L. M. and Sternhall, S., in "ApplicXion of Nuclear Magnetic Resonance Spectroscopy in Organic Chemistry", 2nd edition, Pergamon Press, New York, N.Y., 1969, pp. 184-192. Tarchini, C., Rohmer, M., and Djerassi, C., HELV. CHIM. ACTA, 62_, 1210 (1979). In this publication, chemical shifts of the C-27 and C-21 methyl groups were erroneously reversed. Goad, L. J., Smith, A. G., and Rubinstein, I., PROC. ROY. SOC. LOND., B, x, 223 (1972). Ballantine, J. A. and Roberts, J. C., TETRAHEDRON LETT., 105 (1975). Rohmer, M., Kokke, W. C. M. C., Fenical, W. H., and Djerassi, C., STEROIDS, in press. Idler, D. R., Knalil, M. W., Gilbert, J. D., and Brooks, C. J. W., STEROIDS, 27, 155 (1976). Wardroper, A. M. K., Maxwell, J. R., and Morris, R. J., STEROIDS, 32, 203 (1978).

S Table 1.

TRROXDE

4-Demethyl Sterols Isolated

Sterol Ref. Number

Mt

Rel.Retention Time-3% OV-17

717

frompetrosia p_

No. of Carbons

ficiformis.

Structure -

___-

SRN-1

316

0.30

22

20-Methylpregn-5en-3f3-01

-2

318

0.30

22

20-Methyl-5a-pregnan38-01

-17

-3

370

0.67

26

24-Norcholesta-5,22Edien-3g-ol

2

-4

372

0.67

26

24-Nor-5a-cholest-22Ey en-3B-01

-18

-5

384

0.90

27

24-Methyl-27-norcholesta-5,22E-dien38-01

3

-6

384

0.95

27

Cholesta-5,22E-dien36-01

4

'7

386

1.00

27

Cholest-5-en-38-01

2

-8

386

1.00

27

Sa-Cholest-22E-en-%01

-19

-9

388

1.00

27

5a-Cholestan-36-01

20

-10

388

0.80

27

-1 1

398

1.13

28

24-Methylcholesta-5, 22E-dien-36-01

6

-12

398

1.35

28

24-Methylenecholesterol

7_

-13

398

1.35

28

24-Methylcholesta-7,22dien-36-01

-26

-14

398

1.26

28

23,24-Dimethyl-27-nor;ioAjiJa-5,25-dien-

-15

398

1.22

28

*

-16

398

1.34

28

*

-17

400

1.30

28

Ergost-5-en-38-01

-18

400

1.13

28

5a-Ergost-22E-en-38-ol

-21

-19

402

1.30

28

5a-Ergostan- 38-01

22 .-

Fucosterol

-10

l_

*

8

-,20

412

1.68

29

-21

412

1.81

29

Isofucosterol

-22

412

1.58

29

Ficisterol"

-23

412

1.40

29

24-Ethylcholesta-5,22E-2 dien-38-01

11

S

718

TDROIDIB

Table I (cont.) Sterol Ref. Number

M'

Rel.Retention Time-3% OV-17

No. of Carbons

Structure 26(29)-Dehydroaplysterol

-12

29

Petrosterol

29

-

-13 *

1.60

29

24-Ethylcholest-5en-36-01

-14

414

1.80

29

So-Isofucostan-3~-01

-23

-29

414

1.42

29

Sm-24_Ethylcholest22E-en-38-01

-24

-30

416

1.63

29

24-Ethyl-Swcholestan-38-ol

25

-31

426

2.00

30

~24~)-24-Propyliden~ cholesterol

15 _

-32

426

2.14

30

~24Z)-24-Propyliden~ cholesterol

-24

412

1.70

29

-25

412

1.60

-26

412

1.36

-27

414

-28

* The structures of these trace sterols have not yet been elucidated.