Stereocontrolled synthesis of the four possible 3-methoxy and 3-benzyloxy-16-triazolyl-methyl-estra-17-ol hybrids and their antiproliferative activities

DOI: 10.1016/j.steroids.2019.108500

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Steroids (2019)

Update date:2022-08-29

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Authors:

Kiss, Anita

W?lfling, János

Mernyák, Erzsébet

Frank, éva

Benke, Zsanett

Ashkan Senobar Tahaei, Seyyed

Zupkó, István

Mahó, Sándor

Schneider, Gyula

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Article abstract of DOI:10.1016/j.steroids.2019.108500

The four possible isomers of each of 3-methoxy- and 3-benzyloxyestra-1,3,5(10)-trien-17-ols (5–8 and 9–12) were converted through 16-p-tosyloxymethyl- or 16-bromomethyl derivatives into their 3-methoxy- and 3-benzyloxy-16-azidomethylestra(1,3,5(10)-triene

Full text of DOI:10.1016/j.steroids.2019.108500

S t e r o i d s 1 5 2 (2 019 )1 08500

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Steroids

journal homepage: www.elsevier.com/locate/steroids

Stereocontrolled synthesis of the four possible 3-methoxy and 3-benzyloxy-

16-triazolyl-methyl-estra-17-ol hybrids and their antiproliferative activities

Anita Kiss^a, János Wölﬂing^a, Erzsébet Mernyák^a, Éva Frank^a, Zsanett Benke^b,

Seyyed Ashkan Senobar Tahaei^c, István Zupkó^c,d, Sándor Mahó^e, Gyula Schneider^a,^⁎

^aDepartment of Organic Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary

^bInstitute of Pharmaceutical Chemistry, University of Szeged, H-6720, Eötvös u. 6, H-6720 Szeged. Hungary

^cDepartment of Pharmacodynamics and Biopharmacy, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary

^dInterdisciplinary Centre for Natural Products, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary

^eChemical Works of Gedeon Richter Plc., Gyömrői út 19-21, H-1103 Budapest, Hungary

A R T I C L E I N F O

A B S T R A C T

Keywords:

The four possible isomers of each of 3-methoxy- and 3-benzyloxyestra-1,3,5(10)-trien-17-ols (5–8 and 9–12)

were converted through 16-p-tosyloxymethyl- or 16-bromomethyl derivatives into their 3-methoxy- and 3-

benzyloxy-16-azidomethylestra(1,3,5(10)-triene derivatives (13–16 and 17–20). The regioselective Cu(I)-cata-

lyzed 1,3-dipolar cycloaddition of these compounds with diﬀerent terminal alkynes aﬀorded novel 1,4-dis-

ubstituted diastereomers (21a–f, 22a–f, 23a–f, 24a–f and 25a–f, 26a–f, 27a–f, 28a-f). The antiproliferative

activities of the structurally related triazoles were determined in vitro with the microculture tetrazolium assay on

four malignant human cell lines of gynecological origin (Hela, SiHa, MCF-7 and MDA-MB-231).

3-Methoxy - and 3-benzyloxy-16-

azidomethylestra-1,3,5(10)-triene-17-ols

1,3-Dipolar cycloaddition

4′Substituted-steroid triazoles

Cytotoxic activity

1. Introduction

We have previously reported the preparation and conﬁgurational

assignment of the four possible isomers of the 3-methoxy- and 3-ben-

Among the hybrid natural products, hybrids of steroid frameworks

have attracted great attention due to signiﬁcant biological properties

and numerous therapeutic eﬀects of the basic compound. Steroids have

become ideal synthons for the development of diverse conjugates due to

their rigid framework and potential for varying levels of functionali-

zation, broad biological activity proﬁle and their ability to penetrate

the cell membranes and bind to speciﬁc hormonal receptors [1 –3].

The place, length and orientation of the linkers between the two

parts of the hybrids stems unequivocally from the method of their

synthesis. The literature provides a large number of methods to in-

troduce the linker onto the sterane skeleton. The eﬀect of the length and

character of the linker are very often discussed [4]. However, only

limited information is available with respect to the steric eﬀect of the

linkers on biological properties. As concerns the 16-substituted estro-

genes, usually the 16α-substituted-17β-hydroxy compounds have been

studied. The biological activity has generally not been studied for the

whole isomer series [5].

zyloxy-16-hydroxymethyl-estra-1,3,5(10)-trien-17-ol

derivatives

(5a–8a and 9a–12a) [6–8]. Treatment of 3-methoxy- and 3-benzylox-

yestra-1,3,5(10)-trien-17-ones (1 and 3) with NaOMe and ethyl formate

gave 3-methoxy- and 3-benzyloxy-16-hydroxymethylidene-estra-

1,3,5(10)-trien-17 ones (2 and 4). The C-16 formyl compounds were

reduced with KBH₄in methanol yielding a mixture of three (5a–7a and

9a–11a) of the four possible isomers of each of the 3-methoxy- and 3-

benzyloxy-16-hydroxymethylestra-1,3,5(10)-trien-17-ol isomers in

ratio of 50:45:5 in 94% yield [6,8]. The fourth isomers (8a and 12a)

were prepared from 16α-acetoxymethyl-17β-toluenesulfonate mixed

esters 6d and 10d, respectively, by neighbouring group participation

during solvolysis in aqueous AcOH. The structures of the isomers were

conﬁrmed unambiguously by their IR, ¹H and ¹³C NMR spectra

(Scheme 1) [7,8]. (Scheme 1)

The four 3-methoxy- and 3-benzyloxy-estra-1,3,5(10)-trien-17-ol

isomers (5a–8a and 9a–12a) are suitable starting materials to prepare

16-triazolyl-methyl derivatives. Triazoles are attractive units because of

their stability against metabolic degradation and their ability to form

hydrogen bonds. The Cu(I)-catalysed azide–alkyne cycloaddition

(CuAAC) is a facile method of wide applicability for the introduction of

a triazole moiety into natural products [9]. In these compounds the

In the 16-substituted 17-hydroxysteroids, the two chiral centres

permit four stereochemical modiﬁcations. Since availability of the

complete series of isomers would permit a number of interesting com-

parative examinations.

^⁎Corresponding author.

E-mail address: schneider@chem.u-szeged.hu (G. Schneider).

https://doi.org/10.1016/j.steroids.2019.108500

Received 11 July 2019; Received in revised form 4 September 2019; Accepted 10 September 2019

A v a i l a b l e o n l i n e 1 6 S ep t e m b e r 2 019

A. Kiss, et al.

Steroids152(2019)108500

distilled prior to use. NMR spectra were recorded on a Bruker DRX 500

and Bruker Ascend 500 instrument at 500 (¹H NMR) or 125 MHz (¹³

NMR). Chemical shifts are reported in ppm (δ scale) and coupling

constants (J) in Hertz. For the determination of multiplicities, the J-

MOD pulse sequence was used.

2.2. 3-Methoxy- and 3-benzyloxy-16-azidomethylestra-1,3,5(10)-trienes

(13–16 and 17–20)

2.2.1. General procedure

Compounds 5b–8b [5,6] (470 mg, 1 mmol) or 9c–12c [8] (455 mg,

1 mmol) were dissolved in N,N-dimethylformamide (25 ml) and then

NaN₃(260 mg) was added. The mixture was stirred for 6 h at 80 °C, then

poured into water (50 ml). The precipitate separating out was ﬁltered

oﬀ and subjected to chromatographic separation with CH₂Cl₂/hexane

in diﬀerent ratios.

2.2.2. 3-Methoxy-16β-azidomethyl-estra-1,3,5(10)-trien-17β-ol (13)

Compound 5b (470 mg, 1 mmol) was used for the synthesis as de-

scribed in Section 2.2. The crude product was chromatographed on

silica gel with CH₂Cl₂/hexane (1:3 v/v) to yield pure 13 (318 mg, 93%).

Mp 134–135 °C; R_f= 0.65 (ss A); [α]_D²⁰= + 80 (c 1 in CHCl₃). (Found

C, 70.23; H, 8.05. C₂₀H₂₇N₃O₂(341.45) requires C, 70.35; H, 7.97%).

¹H NMR (δ, ppm, CDCl₃): 0.82 (s, 3H, 18-H₃), 2.87 (m, 2H, 6-H₂), 3.32

(dd, 1H, J = 12.5 Hz, J = 7.5 Hz, 16a-H₂), 3.61 (dd, 1H, J = 12.5 Hz,

J = 7.5 Hz, 16a-H₂), 3.78 (s, 3H, 3-OCH₃), 3.87 (d, 1H, J = 10.0 Hz, 17-

H), 6.64 (d, 1H, J = 2.5 Hz, 4-H), 6.72 (dd, 1H, J = 8.5 Hz, J = 2.5 Hz,

2-H), 7.20 (d, 1H, J = 8.5 Hz, 1-H). ¹³C NMR (δ, ppm, CDCl₃): 12.2 (C-

18), 26.3, 27.5, 29.7, 30.4, 37.7, 38.2, 40.2, 44.0, 44.3 (C-13), 49.0,

53.4 (C-16a), 55.2 (3-OCH₃), 81.5 (C-17), 111.6 (C-2), 113.9 (C-4),

126.2 (C-1), 132.5 (C-10), 137.9 (C-5), 157.7 (C-3).

2.2.3. 3-Methoxy-16α-azidomethylestra-1,3,5(10)-trien-17β-ol (14)

Compound 6b (470 mg, 1 mmol) was used for the synthesis as de-

scribed in Section 2.2. The crude product was chromatographed on

silica gel with CH₂Cl₂/hexane (1:3 v/v) to yield pure 14 (287 mg, 84%).

Mp 85–86 °C; R_f= 0.62 (ss A); [α]_D²⁰= +48 (c 1 in CHCl₃). (Found C,

70.42; H, 7.65. C₂₀H₂₇N₃O₂(341.45) requires C, 70.35; H, 7.97%). ¹H

NMR (δ, ppm, CDCl₃): 0.84 (s, 3H, 18-H₃), 2.86 (m, 2H, 6-H₂), 3.43 (d,

1H, J = 7.5 Hz, 17-H), 3.48 (dd, 2H, J = 6.5 Hz, J = 3.5 Hz, 16a-H₂),

3.78 (s, 3H, 3-OCH₃), 6.63 (s, 1H, 4-H), 6.72 (dd, 1H, J = 6.5 Hz,

J = 2.0 Hz, 2-H), 7.20 (d, 1H, J = 8.5 Hz, 1-H). ¹³C NMR (δ, ppm,

CDCl₃): 11.8 (C-18), 26.1, 27.2, 28.0, 29.7, 36.6, 38.5, 43.6, 43.9, 44.2

(C-13), 48.5, 55.2 (3-OCH₃), 55.6 (C-16a), 85.1 (C-17), 111.5 (C-2),

113.8 (C-4), 126.3 (C-1), 132.4 (C-10), 137.8 (C-5), 157.5 (C-3).

Scheme 1. Reagents and conditions: (i) NaOMe, HCOOEt, anhydrous toluene,

50 °C; (ii) KBH₄, MeOH; (iii) KOAc, CH₃COOH, NaOMe/MeOH.

triazole heterocycles and their substituted derivatives are connected

through a methylene linker to the sterane skeleton. The 16-p-to-

lylsulfonyloxymethyl ester [5,6] and 16-bromomethyl derivatives [10]

of the 16-hydroxymethyl starting materials were used for substitution

reaction with NaN₃in N,N-dimethylformamide to have the desired 3-

methoxy- and 3-benzyloxy-16-azidomethylestra-1,3,5(10)-trien-17-ols

(13–16 and 17–20). From these azido compounds several ^D-ring-sub-

stituted estrane derivatives containing a 1,2,3-triazole ring were syn-

thesized by the reaction of 13–16 and 17–20 with various terminal

alkynes through the use of the “click” chemistry approach to deliver

compounds 21a–e, 22a–e, 23a–e, 24a–e, 25a–e, 26a–e, 27a–e and

28a–e.

2.2.4. 3-Methoxy-16β-azidomethylestra-1,3,5(10)-trien-17α-ol (15)

Compound 7b (470 mg, 1 mmol) were used for the synthesis as

described in Section 2.2. The crude porduct was chromatographed on

silica gel with CH₂Cl₂/hexane (1:3 v/v) to yield pure 15 (275 mg, 80%).

Mp 96–98; ^oC; R_f= 0.60 (ss A); [α]_D²⁰= +68 (c 1 in CHCl₃). (Found C,

70.26; H, 8.15. C₂₀H₂₇N₃O₂(341.45) requires C, 70.35; H, 7.97%). ¹H

NMR (δ, ppm, CDCl₃): 0.76 (s, 3H, 18-H₃), 2.86 (m, 2H, 6-H₂), 3.43 (dd,

2H, J = 7.5 Hz, J = 3.0 Hz, 16a-H₂), 3.61 (s, 1H, 17-H), 3.78 (s, 3H, 3-

OCH₃), 6.64 (d, 1H, J = 2.5 Hz, 4-H), 6.72 (dd, 1H, J = 8.5 Hz,

J = 2.5 Hz, 2-H), 7.22 (d, 1H, J = 8.5 Hz, 1-H). ¹³C NMR (δ, ppm,

CDCl₃): 17.7 (C-18), 25.9, 27.9, 29.8, 30.3, 31.9, 38.6, 43.3, 45.0 (C-

13), 48.9, 55.2 (3-OCH₃), 55.6 (C-16a), 83.0 (C-17), 111.5 (C-2), 113.8

(C-4), 126.3 (C-1), 132.4 (C-10), 137.9 (C-5), 157.5 (C-3).

2. Experimental

2.1. General

Melting points (Mp) were determined on a Koﬂer block and are

uncorrected. Speciﬁc rotations were measured in CHCl₃(c 1) at 20 ^○C

with a POLAMAT-A (Zeiss-Jena) polarimeter and are given in units of

10^–1deg cm^{2 −1}. Elementary analysis data were determined with a

Perkin-Elmer CHN analyzer model 2400. The reactions were monitored

by TLC on Kieselgel-G (Merck Si 254F) layers (0.25 mm thick); solvent

systems (ss): (A) diisopropyl ether, (B) acetone/toluene/hexane

(30:35:35 v/v). The spots were detected by spraying with 5% phos-

phomolybdic acid in 50% aqueous phosphoric acid. The R_fvalues were

determined for the spots observed by illumination at 254 and 365 nm.

Flash chromatography: silica gel 60, 40–63 μm. All solvents were

2.2.5. 3-Methoxy-16α-azidomethylestra-1,3,5(10)-trien-17α-ol (16)

Compound 8b (470 mg, 1 mmol) was used for the synthesis as de-

scribed in Section 2.2. The crude product was chromatographed on

silica gel with CH₂Cl₂/hexane (1:3 v/v) to yield pure 16 (283 mg, 86%).

Mp 118–120 °C; R_f= 0.65 (ss A); [α]_D²⁰= +34 (c 1 in CHCl₃). (Found

C, 70.55; H, 7.78. C₂₀H₂₇N₃O₂(341.45) requires C, 70.35; H, 7.97%).

A. Kiss, et al.

Steroids152(2019)108500

¹H NMR (δ, ppm, CDCl₃): 0.80 (s, 3H, 18-H₃), 2.87 (m, 2H, 6-H₂), 3.35

(dd, 1H, J = 12.0 Hz, J = 6.0 Hz, 16a-H₂), 3.53 (dd, 1H, J = 12.0 Hz,

J = 9.5 Hz, 16a-H₂), 3.78 (s, 3H, 3-OCH₃), 3.84 (d, 1H, J = 6.0 Hz, 17-

H), 6.63 (d, 1H, J = 2.5 Hz, 4-H), 6.72 (dd, 1H, J = 8.5 Hz, 2-H), 7.21

(d, 1H, J = 8.5 Hz, 1-H). ¹³C NMR (δ, ppm, CDCl₃): 17.3 (C-18), 26.1,

28.0, 29.2, 31.3, 39.1, 40.5, 43.6, 46.4 (C-13), 47.0, 52.4 (C-16a), 55.2

(3-OCH₃), 79.9 (C-17), 111.6 (C-2), 114.0 (C-4), 126.3 (C-1), 132.7 (C-

10), 137.9 (C-5), 157.6 (C-3).

3.84 (d, 1H, J = 5.0 Hz, 17-H), 5.04 (s, 2H, Bn-H₂), 6.73 (s, 1H, 4-H),

6.79 (dd, 1H, J = 8.5 Hz, J = 2.5 Hz, 2-H), 7.22 (d, 1H, J = 8.5 Hz, 1-

H), 7.33 (t, 1H, J = 7.5 Hz, 4′-H), 7.39 (t, 2H, J = 7.5 Hz, 3′- and 5′-H),

7.44 (d, 2H, J = 7.5 Hz, 2′- and 6′-H). ¹³C NMR (δ, ppm, CDCl₃): 17.2

(C-18), 26.0, 27.9, 29.0, 29.7, 31.2, 38.9, 40.4, 43.5, 46.3 (C-13), 46.8

(C-16), 52.2 (C-16a), 69.9 (Bn-CH₂), 79.7 (C-17), 112.3 (C-2), 114.8 (C-

4), 126.3 (C-1), 127.4 (C-2′ and -6′), 127.8 (C-4′), 128.5 (C-3′ and -5′),

132.8 (C-10), 137.3 (C-1′), 138.0 (C-5), 156.7 (C-3).

2.2.6. 3-Benzyloxy-16β-azidomethylestra-1,3,5(10)-trien-17β-ol (17)

Compound 9c (455 mg, 1 mmol) was used for the synthesis as de-

scribed in Section 2.2. The crude product was chromatographed on

silica gel with CH₂Cl₂/hexane (1:1 v/v) to yield pure 17 (250 mg, 59%).

Mp 115–117 °C; R_f= 0.45 (ss A). (Found C, 74.55; H, 7.64. C₂₆H₃₁N₃O₂

(417.54) requires C, 74.79; H, 7.48%). ¹H NMR (δ, ppm, CDCl₃): 0.82

(s, 3H, 18-H₃), 2.86 (m, 2H, 6-H₂), 3.33 (dd, 1H, J = 12.0 Hz,

J = 7.5 Hz, 16a-H₂), 3.60 (dd, 1H, J = 12.5 Hz, J = 7.5 Hz, 16a-H₂),

3.87 (d, 1H, J = 9.5 Hz, 17-H), 5.04 (s, 2H, Bn-H₂), 6.73 (s, 1H, 4-H),

6.79 (d, 1H, J = 8.0 Hz, J = 2.0 Hz, 2-H), 7.21 (d, 1H, J = 8.0 Hz, 1-H),

7.32 (t, 1H, J = 7.5 Hz, 4′-H), 7.39 (t, 2H, J = 7.5 Hz, 3′-H and 5′-H),

7.44 (d, 2H, J = 7.5 Hz, 2′-H and 6′-H). ¹³C NMR (δ, ppm, CDCl₃): 12.2

(C-18), 26.2, 27.5, 29.7, 30.3, 37.6, 38.1, 40.1, 43.9, 44.2 (C-13), 48.8

(C-16), 53.3 (C-16a), 69.9 (Bn-CH₂), 81.5 (C-17), 112.3 (C-2), 114.8 (C-

4), 126.3 (C-1), 127.3 (C-2′ and C-6′), 127.8 (C-4′), 128.5 (C-3′ and C-

5′), 132.7 (C-10), 137.3 (C-1′), 137.9 (C-5), 156.8 (C-3).

2.3. General procedure for the synthesis of triazoles (21a–e, 22a–e,

23a–e, 24a–e, 25a–e, 26a–e, 27a–e, and 28a–e)

3-Methoxy-16-azidomethylestra-1,3,5(10)-trien-17-ol

isomers

(13–16) (342 mg, 1 mmol) or 3-benzyloxy-16-azidomethylestra-

1,3,5(10)-trien-17-ol isomers (17–20) 418 mg, 1 mmol) were dissolved

in CH₂Cl₂(20 ml), then CuI (19 mg, 0.10 mmol), Et₃N (0.2 ml, 2 mmol)

and the appropriate terminal alkynes (2 mmol) were added. The mix-

tures were stirred under reﬂux for 24 h, then diluted with water (30 ml)

and extracted with CH₂Cl₂(2 × 30 ml). The combined organic phases

were dried over Na₂SO₄and evaporated in vacuo. The crude products

were puriﬁed by ﬂash chromatography using CH₂Cl₂/ethyl acetate in

diﬀerent ratios.

2.3.1. 3-Methoxy-16β-(4′-cyclopropyl-1′H-1′,2′,3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (21a)

Compound 13 (342 mg, 1 mmol) and cyclopropylacetylene

(2 mmol, 0.22 ml) were used for the synthesis as described in Section

2.3. The crude product was chromatographed on silica gel with CH₂Cl₂/

hexane (3:1 v/v) to yield pure 21a (210 mg, 51%) as a white solid. Mp:

189–191 °C; R_f= 0.44 (ss B). (Found C, 73.84; H, 7.98. C₂₅H₃₃N₃O₂

(407.55) requires C, 73.68; H, 8.16%). ¹H NMR (δ, ppm, CDCl₃): 0.80

(s, 3H, 18-H₃), 0.83 (s, 2H, cyclopropyl-H₂), 0.94 (s, 2H, cyclopropyl-

H₂), 2.72 (d, 1H, J = 7.0 Hz, 1″-H), 2.84 (m, 2H, 6-H₂), 3.77 (s, 3H, 3-

OCH₃), 3.93 (d, 1H, J = 9.5 Hz, 17-H), 4.21 (dd, 1H, J = 13.0 Hz,

J = 6.0 Hz, 16a-H₂), 4.62 (t, 1H, J = 8.0 Hz, 16a-H₂), 6.62 (s, 1H, 4-H),

6.71 (d, 1H, J = 8.5 Hz, 2-H), 7.20 (d, 1H, J = 8.5 Hz, 1-H), 7.29 (s, 1H,

5′-H). ¹³C NMR (δ, ppm, CDCl₃): 6.7 (C-1″), 7.68 (C-2″ and -3″),12.3 (C-

18), 26.2, 27.4, 29.7, 30.8, 37.5, 38.0, 41.4, 43.8, 44.3 (C-16a), 48.7,

51.7 (C-13), 55.2 (3-OCH₃), 80.7 (C-17), 111.5 (C-2), 113.8 (C-4),

126.3 (C-1), 132.4 (C-10), 137.8 (C-5), 157.5 (C-3).

2.2.7. 3-Benzyloxy-16α-azidomethylestra-1,3,5(10)-trien-17β-ol (18)

Compound 10c (455 mg, 1 mmol) was used for the synthesis as

described in Section 2.2. The crude product was chromatographed on

silica gel with CH₂Cl₂/hexane (3:1 v/v) to yield pure 18 (254 mg, 61%).

Mp 75–77 °C; R_f= 0.40 (ss A). (Found C, 74.87; H, 7.32. C₂₆H₃₁N₃O₂

(417.54) requires C, 74.79; H, 7.48%). ¹H NMR (δ, ppm, CDCl₃): 0.84

(s, 3H, 18-H₃), 2.85 (m, 2H, 6-H₂), 3.44 (t, 1H, J = 8.0 Hz, 17-H), 3.48

(m, 2H, 16a-H₂), 5.04 (s, 2H, Bn-H₂), 6.73 (s, 1H, 4-H), 6.79 (d, 1H,

J = 8.5 Hz, 2-H), 7.21 (d, 1H, J = 8.5 Hz, 1-H), 7.32 (t, 1H, J = 7.0 Hz,

4′-H), 7.39 (t, 2H, J = 7.0 Hz, 3′- and 5′-H), 7.44 (d, 2H, J = 7.0 Hz, 2′-

and 6′-H). ¹³C NMR (δ, ppm, CDCl₃): 11.8 (C-18), 26.1, 27.2, 27.9,

29.7, 36.6, 38.5, 43.6, 43.9, 44.2 (C-13), 48.6 (C-16), 55.6 (C-16a),

69.9 (Bn-CH₂), 85.1 (C-17), 112.3 (C-2), 114.8 (C-4), 126.3 (C-1), 127.4

(C-2′ and -6′), 127.8 (C-4′), 128.5 (C-3′ and -5′), 132.7 (C-10), 137.3 (C-

1′), 137.9 (C-5), 156.8 (C-3).

2.3.2. 3-Methoxy-16β-(4′-cyclopentyl-1′H-1′,2′,3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (21b)

2.2.8. 3-Benzyloxy-16β-azidomethyl-estra-1,3,5(10)-trien-17α-ol (19)

Copound 11c (455 mg, 1 mmol) was used for the synthesis as de-

scribed in Section 2.2. The crude product was chromatographed on

silica gel with CH₂Cl₂/hexane (3:1 v/v) to yield pure 19 (23. mg, 40%).

Mp. 134–136 °C. R_f= 0.38 (ss A). (Found C, 74.92; H, 7.37.

Compound 13 (342 mg, 1 mmol) and cyclopentylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel with CH₂Cl₂to yield

pure 21b (370 mg, 85%) as a white solid. Mp: 191–192 °C; R_f= 0.46 (ss

B). (Found C, 74.62; H, 8.42. C₂₇H₃₇N₃O₂(435.60) requires C, 74.45;

H, 8.56%). ¹H NMR (δ, ppm, CDCl₃): 0.79 (s, 3H, 18-H₃), 2.85 (m, 2H,

6-H₂), 3.19 (s, 1H, 1″-H), 3.77 (s, 3H, 3-OCH₃), 3.94 (d, 1H, J = 9.5 Hz,

17-H), 4.24 (d, 1H, J = 8.0 Hz, 16a-H₂), 4.65 (s, 1H, 16a-H₂), 6.62 (s,

1H, 4-H), 6.71 (d, 1H, J = 8.5 Hz, 2-H), 7.20 (d, 1H, J = 8.5 Hz, 1-H),

7.34 (s, 1H, 5′-H). ¹³C NMR (δ, ppm, CDCl₃): 12.3 (C-18), 25.1 (C-3″

and -4″), 26.2, 27.4, 29.7 (C-2″ and 5″), 30.8, 33.2, 36.7, 37.5, 38.0,

42.4 (C-16a), 43.8, 44.3 (C-13), 48.7, 51.8, 55.2 (3-OCH₃), 62.1 (C-16),

80.7 (C-17), 111.5 (C-2), 113.7 (C-4), 126.3 (C-1), 132.4 (C-10), 137.8

(C-5), 157.4 (C-3).

₂₆H₃₁N₃O₂(417.54) requires C, 74.79; H, 7.48%). ¹H NMR (δ, ppm,

CDCl₃): 0.84 (s, 3H, 18-H₃), 2.85 (m, 2H, 6-H₂), 3.43 (d, 2H, J = 8.0 Hz,

17-H), 3.48 (t, 2H, J = 6.5 Hz, 16a-H₂), 5.04 (s, 2H, Bn-H₂), 6.73 (s, 1H,

4-H), 6.79 (d, 1H, J = 8.0 Hz, 2-H), 7.22 (d, 1H, J = 8.0 Hz 1-H), 7.33

(d, 1H, J = 7.0 Hz, 4′-H), 7.39 (t, 2H, J = 7.0 Hz, 3′- and 5′-H), 7.44 (d,

2H, J = 7.0 Hz, 2′- and 6′-H). ¹³C NMR (δ, ppm, CDCl₃): 11.8 (C-18),

26.1, 27.2, 28.0, 29.7, 36.6, 38.4, 43.5, 43.9, 44.1 (C-13), 48.5 (C-16),

55.6 (C-16a), 69.9 (Bn-CH₂), 85.1 (C-17), 112.3 (C-2), 114.8 (C-4),

126.3 (C-1), 127.4 (C-2′ and -6′), 127.8 (C-4′), 128.5 (C-3′ and -5′),

132.7 (C-10), 137.3 (C-1′), 137.9 (C-5), 156.7 (C-3).

2.2.9. 3-Benzyloxy-16α-azidomethyl-estra-1,3,5(10)-trien-17α-ol (20)

Compound 12c (455 mg, 1 mmol) was used for the synthesis as

described in Section 2.2. The crude was chromatographed on silica gel

with CH₂Cl₂/hexane (1:1 v/v) to yield pure 20 (330 mg, 79%). Mp

90–92 °C. R_f= 0.45 (ss A). (Found C, 74.68; H, 7.55. C₂₆H₃₁N₃O₂

(417.54) requires C, 74.79; H, 7.48%). ¹H NMR (δ, ppm, CDCl₃): 0.79

(s, 3H, 18-H₃), 2.71 (m, 2H, 6-H₂), 3.35 (dd, 1H, J = 12.0 Hz,

J = 6.5 Hz, 16a-H₂), 3.52 (dd, 1H, J = 12.0 Hz, J = 6.5 Hz, 16a-H₂),

2.3.3. 3-Methoxy-16β-(4′-cyclohexyl-1′H-1′,2′,3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (21c)

Compound 13 (342 mg, 1 mmol) and cyclohexylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel with ethyl acetate/

CH₂Cl₂(1:99 v/v) to yield pure 21c (370 mg, 82%) as a white solid. Mp:

189–190 °C; R_f= 0,40 (ss B). (Found C, 74.92; H, 8.55. C₂₈H₄₁N₃O₂

(449.63) requires C, 74.80; H, 8.74%). ¹H NMR (δ, ppm, CDCl₃): 0.79

A. Kiss, et al.

Steroids152(2019)108500

(s, 3H, 18-H₃), 2.84 (m, 2H, 6-H₂), 3.77 (s, 3H, 3-OCH₃), 3.94 (d, 1H,

J = 9.5 Hz, 17-H), 4.24 (m, 1H, 16a-H₂), 4.65 (m, 1H, 16a-H₂), 6.62 (s,

1H, 4-H), 6.71 (d, 1H, J = 8.5 Hz, 2-H), 7.20 (d, 1H, J = 8.5 Hz, 1-H),

7.32 (s, 1H, 5′-H). ¹³C NMR (δ, ppm, CDCl₃): 12.3 (C-18), 26.0, 26.1 (C-

2″ and -6″), 26.2, 27.4, 29.7, 30.8, 33.0, 37.5, 38.0, 41.4 (C-1″), 43.8,

44.3 (C-13), 48.3, 55.2 (3-OCH₃), 62.1, 80.7 (C-17), 111.5 (C-2), 113.7

(C-4), 126.3 (C-1), 132.4 (C-10), 137.8 (C-5), 157.4 (C-3).

2.3.7. 3-Methoxy-16a-(4′-cyclopropyl-1′H-1′,2′,3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (22a)

Compound 14 (342 mg, 1 mmol) and cyclopropylacetylene

(2 mmol, 0.22 ml) were used for the synthesis as described in Section

2.3. The crude product was chromatographed on silica gel with ethyl

acetate/CH₂Cl₂(5:95 v/v) to yield pure 22a (261 mg, 64%) as a white

solid. Mp: 67–69 °C; R_f= 0.35 (ss B). (Found C, 73.55; H, 7.98.

₂₅H₃₃N₃O₂(407.55) requires C, 73.68; H, 8.16%). ¹H NMR (δ, ppm,

2.3.4. 3-Methoxy-16β-(4′-phenyl-1′H-1′,2′,3′-triazol-1′-yl)methylestra-

1,3,5(10)-trien-17β-ol (21d)

CDCl₃): 0.82 (m, 5H, 18-H₃and cyclopropyl-H₂), 0.95 (m, 2H, cyclo-

propyl-H₂), 2.83 (m, 2H, 6-H₂), 3.53 (d, 1H, J = 7.5 Hz, 17-H), 3.77 (s,

3H, 3-OCH₃), 4.35 (t, 1H, J = 7.5 Hz, 16a-H₂), 4.44 (dd, 1H,

J = 13.5 Hz, J = 7.5 Hz, 16a-H₂), 6.62 (d, 1H, J = 2.0 Hz, 4-H), 6.70

Compound 13 (342 mg, 1 mmol) and phenylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel with ethyl acetate/

CH₂Cl₂(1:99 v/v) to yield pure 21d (368 mg, 83%) as a white solid.

Mp: 232–234 °C; R_f= 0.35 (ss B). (Found C, 75.98; H, 7.36.

(dd, 1H, J = 8.5 Hz, J = 2.0 Hz, 2-H), 7.18 (d, 1H, J = 8.5 Hz, 1-H). ¹³

NMR (δ, ppm, CDCl₃): 6.7 (C-1″), 7.7 (C-2″ and -3″), 11.8 (C-18), 26.1,

27.2, 28.2, 29.7, 36.6, 38.4, 43.9, 44.3, 44,3 (C-16a), 48.3, 54.5 (C-13),

62.1 (3-OCH₃), 85.1 (C-17), 111.5 (C-2), 113.8 (C-4), 126.2 (C-1),

132.3 (C-10), 137.8 (C-5), 157.4 (C-3).

₂₈H₃₃N₃O₂(443.58) requires C, 75.81; H, 7.50%). ¹H NMR (δ, ppm,

CDCl₃): 0.79 (s, 3H, 18-H₃), 2.73 (m, 2H, 6-H₂), 3.68 (s, 3H, 3-OCH₃),

3.79 (d, 1H, J = 10.0 Hz, 17-H), 4.20 (t, 1H, J = 13.5 Hz, 16a-H₂), 4.63

(dd, 1H, J = 13.5 Hz, J = 4.5 Hz, 16a-H₂), 6.59 (s, 1H, 4-H), 6.67 (d,

1H, J = 8.5 Hz, 2-H), 7.16 (d, 1H, J = 8.5 Hz, 1-H), 7.32 (t, 1H,

J = 7.5 Hz, 4″-H), 7.44 (t, 2H, J = 7.5 Hz, 3″- and 5″-H), 7.85 (d, 2H,

J = 7.5 Hz, 2″- and 6″-H), 8.60 (s, 1H, 5′-H). ¹³C NMR (δ, ppm, CDCl₃):

12.4 (C-18), 25.8, 26.9, 29.1, 30.0, 36.9, 37.8, 40.4, 43.3, 43.7 (C-13),

47.8, 52.3 (C-16a), 54.8 (3-OCH₃), 79.5 (C-17), 111.4 (C-2), 113.3 (C-

4), 121.5 (C-5′), 124.5 (C-2″ and -6″), 126.0 (C-1), 127.6 (C-4″), 127.8

(C-3″ and -5″), 130.9 (C-1″), 132.0 (C-10), 137.3 (C-5), 146.0 (C-4′),

156.9 (C-3).

2.3.8. 3-Methoxy-16a-(4′-cyclopentyl-1′H-1′,2′,3′-triazol-1-yl)

methylestra-1,3,5(10)-trien-17β-ol (22b)

Compound 14 (342 mg, 1 mmol) and cyclopentylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel with ethyl acetate/

CH₂Cl₂(5:95 v/v) to yield pure 22b (290 mg, 66%) as a white solid.

Mp: 163–165 °C; R_f= 0.32 (ss B). (Found C, 74.63; H, 8.41.

₂₇H₃₇N₃O₂(435.60) requires C, 74.45; H, 8.56%). ¹H NMR (δ, ppm,

CDCl₃): 0.83 (s, 3H, 18-H₃), 1.68 (s, 4H, 3″- and 4″-H₂), 2.83 (m, 2H, 6-

H₂), 3.19 (m, 1H, 1″-H), 3.56 (d, 1H, J = 7.0 Hz, 17-H), 3.77 (s, 3H, 3-

OCH₃), 4.43 (m, 2H, 16a-H₂), 6.62 (s, 1H, 4-H), 6.70 (d, 1H, J = 8.5 Hz,

2-H), 7.19 (d, 1H, J = 8.5 Hz, 1-H), 7.35 (s, 1H, 5′-H). ¹³C NMR (δ,

ppm, CDCl₃): 11.9 (C-18), 25.1 (C-3″ and -4″), 26.1, 27.2, 28.3, 29.7 (C-

2″ and -5″), 33.2, 36.6, 38.4, 43.9, 44.2, 44.3 (C-13), 48.4, 55.2 (3-

OCH₃), 62.1 (C-16a), 85.3 (C-17), 111.5 (C-2), 113.8 (C-4), 126.3 (C-1),

132.3 (C-10), 137.8 (C-5), 157.5 (C-3).

2.3.5. 3-Methoxy-16β-(4′-nitro-benzoyloxymethyl-1′H-1′,2,’3′-triazol-1′-

yl)methylestra-1,3,5(10)-trien-17β-ol (21e)

Compound 13 (342 mg, 1 mmol) and propargyl 4-nitrobenzoate

(2 mmol, 410 mg) were used for the synthesis as described in Section

2.3. The crude product was chromatographed on silica gel with ethyl

acetate/CH₂Cl₂(5:95 v/v) to yield pure 21e (475 mg, 86%) as a yellow

solid. Mp: 134–135.5 °C; R_f= 30 (ss B). (Found C, 66.12; H, 6.08.

₃₀H₃₄N₄O₆(546.61) requires C, 65.92; H, 6.27%). ¹H NMR (δ, ppm,

2.3.9. 3-Methoxy-16a-(4′-cyclohexyl-1′H-1′,2′,3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (22c)

CDCl₃): 0.73 (s, 3H, 18-H₃), 2.70 (m, 2H, 6-H₂), 3.66 (s, 3H, 3-OCH₃),

4.18 (dd, 1H, J = 13.5 Hz, J = 11.5 Hz, 16a-H2), 4.58 (dd, 1H,

J = 13.5 Hz, J = 4.5 Hz, 16a-H₂), 5.02 (d, 1H, J = 4.5 Hz, 17-H), 5.44

(s, 2H, 4′-H₂), 6.55 (d, 1H, J = 1.5 Hz, 4-H), 6.63 (dd, 1H, J = 8.5 Hz,

J = 2.0 Hz, 2-H), 7.12 (d, 1H, J = 8.5 Hz, 1-H), 8.16 (d, 2H, J = 8.5 Hz,

3″- and 5″-H), 8.31 (t, 3H, J = 8.5 Hz, 2″- and 6″-H, 5′-H). ¹³C NMR (δ,

ppm, CDCl₃): 12.3 (C-18), 25.8, 26.9, 29.1, 30.0, 36.9, 37.8, 40.4, 43.3,

43.7 (C-13), 47.8, 52.2 (C-16a), 54.7 (3-OCH₃), 58.7 (4′-CH₂), 79.5 (C-

17), 111.3 (C-2), 113.3 (C-4), 123.8 (C-2″ and -6″), 125.1 (C-5′), 126.0

(C-1), 130.6 (C-3″ and -5″), 131.9 (C-10), 134.7 (C-1″), 137.2 (C-5),

141.0 (C-4″), 150.2 (C-4′), 156.9 (C-3), 163.9 (C]O).

Compound 14 (342 mg, 1 mmol) and cyclohexylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel with ethyl acetate/

CH₂Cl₂(5:95 v/v) to yield pure 22c (345 mg, 76%) as a white solid. Mp:

80–82 °C; R_f= 0.34 (ss B). (Found 74.96; H, 8.54. C₂₈H₄₁N₃O₂(449.63)

requires C, 74.80; H, 8.74%). ¹H NMR (δ, ppm, CDCl₃): 0.83 (s, 3H, 18-

H₃), 2.83 (m, 2H, 6-H₂), 3.55 (s, 1H, 17-H), 3.77 (s, 3H, 3-OCH₃), 4.46

(s, 2H, 16a-H₂), 6.62 (d, 1H, J = 2.0 Hz, 4-H), 6.70 (dd, 1H, J = 8.5 Hz,

J = 2.0 Hz, 2-H), 7.19 (d, 1H, J = 8.5 Hz, 1-H). ¹³C NMR (δ, ppm,

CDCl₃): 11.9 (C-18), 26.0 and 26.1 (C-2″ and -6″, C-3″ and -5″), 27.2,

28.3, 29.7, 36.6, 38.4, 43.9, 44.3 (C-13), 48.4, 55.2 (3-OCH₃), 62.1 (C-

1″), 62.1 (C-16a), 85.2 (C-17), 111.5 (C-2), 113.8 (C-4), 126.2 (C-1),

132.3 (C-10), 137.8 (C-5), 157.4 (C-3).

2.3.6. 3-Methoxy-16β-(4′-hydroxymethyl-1′H-1′,2′,3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (21f)

Compound 13 (274 mg, 0.5 mmol) was dissolved in methanol

(10 ml) containing NaOCH₃(14 mg, 0.25 mmol), and the solution was

allowed to stand for 24 h. It was then diluted with water, and the

precipitate separating out was ﬁltered oﬀ and recrystallized from a

mixture of ethyl acetate/hexane to aﬀord 21f (171 mg, 86%) as a white

crystalline material. Mp: 194–195 °C; R_f= 0.25 (ss B). (Found C, 69.23;

H, 8.04. C₂₃H₃₁N₃O₃(397.51) requires C, 69.49; H, 7.86%). ¹H NMR (δ,

ppm, DMSO‑d₆): 0.76 (s, 3H, 18-H₃), 2.71 (m, 2H, 6-H₂), 3.68 (s, 3H, 3-

OCH₃), 3.76 (d, 1H, J = 5.5 Hz, 17-H), 4.14 (t, 1H, J = 12.5 Hz, 16a-

H₂), 4.49 (m, 3H, 4′-H₂and 16a-H₂), 5.03 (d, 1H, J = 3.5 Hz, 17-OH),

5.15 (brs, 1H, CH₂-OH), 6.59 (s, 1H, 4-H), 6.66 (d, 1H, J = 8.5 Hz, 2-H),

7.16 (d, 1H, J = 8.5 Hz, 1-H), 7.99 (s, 1H, 5′-H). ¹³C NMR (δ, ppm,

DMSO‑d₆): 12.4 (C-18), 25.9, 26.9, 29.2, 30.0, 36.9, 37.9, 40.5, 43.4,

43.8 (C-13), 47.8, 52.0 (C-16a), 54.8 (3-OCH₃), 55.0 (4′-CH₂), 79.5 (C-

17), 111.4 (C-2), 113.4 (C-4), 122.8 (C-5′), 126.1 (C-1), 132.0 (C-10),

137.3 (C-5), 147.6 (C-4′), 157.0 (C-3).

2.3.10. 3-Methoxy-16a-(4′-phenyl-1′H-1′,2′,3′-triazol-1′-yl)methylestra-

1,3,5(10)-trien-17β-ol (22d)

Compound 14 (342 mg, 1 mmol) and phenylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel ethyl acetate/CH₂Cl₂

(5:95 v/v) to yield pure 22d (368 mg, 82%) as a white solid. Mp:

204–205 °C; R_f= 0.38 (ss B). (Found C, 75.63; H, 7.72. C₂₈H₃₃N₃O₂

(443.58) requires C, 75.81; H, 7.50%). ¹H NMR (δ, ppm, DMSO‑d₆):

0.73 (s, 3H, 18-H₃), 2.73 (m, 2H, 6-H₂), 3.67 (s, 3H, 3-OCH₃), 4.36 (t,

1H, J = 13.5 Hz, 16a-H₂), 4.54 (dd, 1H, J = 13.5 Hz, J = 4.0 Hz, 16a-

H₂), 4.91 (d, 1H, J = 4.0 Hz, 17-H), 6.58 (s, 1H, 4-H), 6.67 (d, 1H,

J = 8.5 Hz, 2-H), 7.15 (d, 1H, J = 8.5 Hz, 1-H), 7.32 (t, 1H, J = 7.0 Hz,

4″-H), 7.44 (t, 2H, J = 7.0 Hz, 3″- and 5″-H), 7.86 (d, 2H, J = 7.0 Hz,

2″- and 6″-H), 8.61 (s, 1H, 5′-H). ¹³C NMR (δ, ppm, DMSO‑d₆): 11.8 (C-

18), 25.8, 26.7, 27.3, 29.1, 36.3, 38.1, 43.4, 43.5, 43.8, 47.5, 53.5 (C-

A. Kiss, et al.

Steroids152(2019)108500

13), 54.8 (3-OCH₃), 83.1 (C-17), 111.4 (C-2), 113.3 (C-4), 121.4 (C-5′),

125.0 (C-2″ and -6″), 126.0 (C-1), 127.6 (C-4″), 128.8 (C-3″ and -5″),

130.8 (C-1″), 132.0 (C-10), 137.3 (C-5), 146.1 (C-4′), 156.9 (C-3).

crystalline material. Mp: 67–68 °C; R_f= 0.36 (ss B). (Found C, 74.28; H,

8.47. C₂₇H₃₇N₃O₂(435.60) requires C, 74.45; H, 8.56%). ¹H NMR (δ,

ppm, CDCl₃): 0.75 (s, 3H, 18-H₃), 2.85 (m, 2H, 6-H₂), 3.68 (s, 1H, 17-

H), 3.77 (s, 3H, 3-OCH₃), 4.44 (d, 2H, J = 15.0 Hz, 16a-H₂), 6.62 (s,

1H, 4-H), 6.70 (d, 1H, J = 8.5 Hz, 2-H), 7.20 (t, 1H, J = 8.5 Hz, 1-H).

¹³C NMR (δ, ppm, CDCl₃): 17.9 (C-18), 25.1 (C-3″ and -4″), 25.9, 26.1,

27.2, 28.0, 29.7, 30.4, 31.8, 36.6 (C-16a), 38.5, 43.3, 43.8, 45.1 (C-13),

48.9, 55.2 (3-OCH₃), 62.1 (C-1″), 82.6 (C-17), 111.5 (C-2), 113.7 (C-4),

113.8 (C-5′), 126.2 (C-1), 132.1 (C-10), 137.8 (C-5), 137.8 (C-4′), 157.4

(C-3).

2.3.11. 3-Methoxy-16a-[4′(4′’-nitro-benzoyloxymethyl)-1′H-1′,2′,3′-

triazol-1′-yl]methylestra-1,3,5(10)-trien-17β-ol (22e)

Compound 14 (342 mg, 1 mmol) and propargyl 4-nitrobenzoate

(2 mmol, 410 mg) were used for the synthesis as described in Section

2.3. The crude product was chromatographed on silica gel with ethyl

acetate/CH₂Cl₂(5:95 v/v) to yield pure 22e (445 mg, 81%) as a yellow

solid. Mp: 86–88 °C; R_f= 0.28 (ss B). (Found C, 66.08; H, 6.43.

C₃₀H₃₄N₄O₆(546.61) requires C, 65.92; H, 6.27%). ¹H NMR (δ, ppm,

DMSO‑d₆): 0.69 (s, 3H, 18-H₃), 2.68 (m, 2H, 6-H₂), 3.57 (s, 3H, 3-

OCH₃), 4.38 (dd, 1H, J = 13.5 Hz, J = 9.0 Hz, 16a-H₂), 4.52 (dd, 1H,

J = 13.5 Hz, J = 4.5 Hz, 16a-H₂), 4.86 (d, 1H, J = 4.5 Hz, 17-H), 5.46

(s, 2H, 4′-H₂), 6.55 (d, 1H, J = 1.5 Hz, 4-H), 6.63 (dd, 1H, J = 8.5 Hz,

2-H), 7.10 (d, 1H, J = 8.5 Hz, 1-H), 8.16 (d, 2H, J = 8.5 Hz, 3″- and 5″-

H), 8.28 (d, 2H, J = 8.5 Hz, 2″- and 6″-H), 8.31 (s, 1H, 5′-H). ¹³C NMR

(δ, ppm, DMSO‑d₆): 11.7 (C-18), 25.7, 26.6, 27.1, 29.0, 36.4, 38.0,

43.3, 43.4 (C-13), 43.7, 47.7, 53.1 (C-16a), 54.7 (3-OCH₃), 58.6 (4″-

CH₂), 82.8 (C-17), 111.3 (C-2), 113.3 (C-4), 123.8 (C-2″ and -6″), 125.2

(C-5′), 125.9 (C-1), 130.6 (C-3″ and -5″), 131.8 (C-10), 134.7 (C-1′),

137.2 (C-5), 141.1 (C-4″), 150.2 (C-4′), 156.9 (C-3), 163.9 (C]O).

2.3.15. 3-Methoxy-16β-(4′-cyclohexyl-1′H-1′,2′,3′-triazol-1′-yl)

methyestra-1,3,5(10)-trien-17a-ol (23c)

Compound 15 (342, 1 mmol) and cyclohexylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel with ethyl acetate/

CH₂Cl₂(5:95 v/v) to yield pure 23c (306 mg, 68%) as a white solid. Mp:

90–92 °C; R_f= 0.37 (ss B). (Found C, 74.95; H, 8.83. C₂₈H₄₁N₃O₂

(449.63) requires C, 74.80; H, 8.74%). ¹H NMR (δ, ppm, CDCl₃): 0.75

(s, 3H, 18-H₃), 2.84 (m, 2H, 6-H₂), 3.67 (d, 1H, J = 1.0 Hz, 17-H), 3.77

(S, 3H, 3-OCH₃), 4.43 (m, 1H, 16a-H₂), 6.62 (d, 1H, J = 2.5 Hz, 4-H),

6.71 (dd, 1H, J = 8.5 Hz, J = 2.5 Hz, 2-H), 7.20 (t, 1H, J = 8.5 Hz, 1-

H), 7.35 (s, 1H, 5′-H). ¹³C NMR (δ, ppm, CDCl₃): 17.9 (C-18), 25.9,

26.0, 26.1 (C-2″ and -6″), 28.0, 29.7, 30.4, 31.8, 33.0, 35.2 (C-1″), 36.6,

38.5, 43.3, 45.1 (C-13), 48.9, 49.1, 54.3 (C-16a), 55.2 (3-OCH₃), 82.6

(C-1), 132.4 (C-10), 137.8 (C-5), 153.7 (C-4′), 157.7 (C-3).

2.3.12. 3-Methoxy-16a-(4′-hydroxymethyl-1′H-1′,2′3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (22f)

Compound 22e (274 mg, 0.5 mmol) was dissolved in methanol

(10 ml) containing NaOCH₃(14 mg, 0.25 mmol), and the solution was

allowed to stand for 24 h. It was then diluted with water, and the

precipitate separating out was ﬁltered oﬀ and recrystallized from a

mixture of ethyl acetate/hexane to aﬀord 22f (175 mg, 88%) as a white

crystalline product. Mp: 98–100 °C; R_f= 0.28 (ss B). (Found C, 69.74;

H, 7.72. C₂₃H₃₁N₃O₃(397.51) requires C, 69.49; H, 7.86%). ¹H NMR (δ,

ppm, CDCl₃): 0.81 (s, 3H, 18-H₃), 2.82 (m, 2H, 6-H₂), 3.50 (d, 1H,

J = 7.0 Hz, 17-H), 3.76 (s, 3H, 3-OCH₃), 4.42 (d, 2H, J = 7.0 Hz, 16a-

H₂), 4.71 (s, 2H, 4′-H₂), 6.61 (s, 1H, 4-H), 6.69 (d, 1H, J = 8.5 Hz, 2-H),

7.17 (d, 1H, J = 8.5 Hz, 1-H), 7.68 (s, 1H, 5′-H). ¹³C NMR (δ, ppm,

CDCl₃): 11.9 (C-18), 26.1, 27.2, 28.2, 29.6, 36.5, 38.4, 43.8, 44.0, 44.4

(C-13), 48.2, 54.6 (C-16a), 55.2 (3-OCH₃), 56.0 (4′-CH₂), 85.1 (C-17),

111.5 (C-2), 113.8 (C-4), 126.3 (C-1), 132.3 (C-10), 137.8 (C-5), 157.4

(C-3).

2.3.16. 3-Methoxy-16β-(4′-phenyl-1′H-1′,2′,3′-triazol-1′-yl)methy-estra-

1,3,5(10)-trien-17a-ol (23d)

Compound 15 (342 mg, 1 mmol) and phenylacetylene (2 mmol,

0.22 ml) were used for the synthesis as described in Section 2.3. The

crude product was chromatographed on silica gel with ethyl acetate/

CH₂Cl₂(2.5:97.5 v/v) to yield pure 23d (299 mg, 67%) as white crys-

tals. Mp: 173–174 °C; R_f= 0.34 (ss B). (Found C 75.98; H, 7.33.

₂₈H₃₃N₃O₂(443.58) requires C, 75.81; H, 7.50%). ¹H NMR (δ, ppm,

CDCl₃): 0.79 (s, 3H, 18-H₃), 2.85 (m, 2H, 6-H₂), 3.71 (d, 1H, J = 1.5 Hz,

17-H), 3.78 (s, 3H, 3-OCH₃), 4.46 (dd, 1H, J = 13.5 Hz, J = 8.0 Hz,

16a-H₂), 4.55 (dd, 1H, J = 13.5 Hz, J = 8.0 Hz, 16a-H₂), 6.63 (d, 1H,

J = 2.0 Hz, 4-H), 6.72 (dd, 1H, J = 8.5 Hz, J = 2.5 Hz, 2-H), 7.21 (d,

1H, J = 8.5 Hz, 1-H), 7.27 (t, 1H J = 7.5 Hz, 4″-H), 7.42 (t, 2H,

J = 7.5 Hz, 3″- and 5″-H), 7.83 (d, 2H, J = 7.5 Hz, 2″- and 6″-H), 7.87

(s, 1H, 5′-H). ¹³C NMR (δ, ppm, CDCl₃): 17.9 (C-18), 25.9, 27.9, 29.7,

30.4, 31.8, 38.5, 43.3, 45.1, (C-13), 48.8, 49.1, 54.5 (C-16a), 55.2 (3-

OCH₃), 82.5 (C-17), 111.5 (C-2), 113.7 (C-4), 119.6 (C-5′), 125.7 (C-2″

and -6″), 126.3 (C-1), 128.1 (C-4″), 128.8 (C-3″ and -5″), 130.5 (C-1″),

132.4 (C-10), 137.8 (C-5), 147.8 (C-4′), 157.4 (C-3).

2.3.13. 3-Methoxy-16a-(4′-cyclopropyl-1′H-1′,2′,3′-triazol-1′-yl)

methylestra-1,3,5(10)-trien-17β-ol (23a)

Compound 15 (342 mg, 1 mmol) and cyclopropylacetylene

(2 mmol, 0.22 ml) were used for the synthesis as described in Section

2.3. The crude product was chromatographed on silica gel with ethyl

acetate/CH₂Cl₂(1:99 v/v) to yield pure 23a (261 mg, 64%) as a white

solid. Mp: 67–69 °C; R_f= 0.32 (ss B). (Found C, 73.85; H, 8.32.

2.3.17. 3-Methoxy-16β-[4′(4″-nitro-benzoyloxymethyl)-1′H-1′,2′,3′-

triazol-1′-yl)methylestra-1,3,5(10)-trien-17a-ol (23e)

₂₅H₃₃N₃O₂(407.55) requires C, 73.68; H, 8.16%). ¹H NMR (δ, ppm,

Compound 15 (342, 1 mmol) and propargyl 4-nitro benzoate

(2 mmol, 410 mg) were used for the synthesis as described in Section

2.3. The crude product was chromatographed on silica gel with ethyl

acetate/CH₂Cl₂(5:95 v/v) to yield pure 23e (370 mg, 67%) as a yellow

crystalline material. Mp: 62–63 °C; R_f= 0.38 (ss B). (Found C, 66.14; H,

6.42. C₃₀H₃₄N₄O₆(546.61) requires C, 65.92; H, 6.27%). ¹H NMR (δ,

ppm, DMSO‑d₆): 0.65 (s,3H, 18-H₃), 2.74 (m,2H, 6-H₂), 3.68 (s, 3H, 3-

OCH₃), 4.41 (dd, 1H, J = 13.0 Hz, J = 8.5 Hz, 16a-H₂), 4.56 (dd, 1H,

J = 13.0 Hz, J = 8.5 Hz, 16a-H₂), 4.63 (d, 1H, J = 4.5 Hz, 17-H), 6.58

(s, 1H, 4-H), 6.66 (d, 1H, J = 8.5 Hz, 2-H), 7.16 (d, 1H, J = 8.5 Hz, 1-

H), 8.19 (d, 2H, J = 8.5 Hz, 3″- and 5″-H), 8.34 (d, 2H, J = 8.5 Hz, 2″-

and 6″-H). ¹³C NMR (δ, ppm, DMSO‑d₆): 17.5 (C-18), 25.6, 27.5, 29.6,

31.8, 38.2, 43.0, 44.5, 47.9 (C-13), 48.2, 49.1, 53.6 (C-16a), 54.8 (3-

OCH₃), 58.7 (4′-CH₂), 80.8 (C-17), 111.3 (C-2), 113.3 (C-4), 123.8 (C-

1), 126.1 (C-5′), 130.6 (C-2″ and -6″), 131.9 (C-3″ and -5″), 133.0 (C-

10), 134.7 (C-1″), 137.3 (C-5), 141.4 (C-4″), 150.2 (C-4′), 156.9 (C-3),

163.9 (C]O).