TY  - JOUR
AU  - Bjelaković, Mira
AU  - Krstić, Natalija
AU  - Tinant, Bernard
AU  - Kalvoda, Jaroslav
AU  - Csanadi, Janos
AU  - Pavlović, Vladimir D.
PY  - 2005
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4186
AB  - The conformations of (Z)‐ and (E)‐5‐oxo‐B‐nor‐5,10‐secocholest‐1(10)‐en‐3β‐yl acetates (2 and 3, resp.) were examined by a combination of X‐ray crystallographic analysis and NMR spectroscopy, with emphasis on the geometry of the cyclononenone moiety. The 1H‐ and 13C‐NMR spectra showed that the unsaturated nine‐membered ring of (E)‐isomer 3 in C6D6 and (D6)acetone solution exists in a sole conformation of type B1, which is similar to its solid‐state conformation. The (Z)‐isomer 2 in C6D6, CDCl3, and (D6)acetone solution, however, exists in two conformational forms of different families, with different orientation of the carbonyl group, the predominant form (85%) corresponding to the conformation of type A1 and the minor (15%) to the conformation A2 present also in the crystalline state. In this solid‐state conformations of the nine‐membered ring of both compounds, the 19‐Me and 5‐oxo groups are ‘β’‐oriented. The NMR analysis suggests that the nine‐membered ring of 4 has a conformation of type C1 in CDCl3 solution.
PB  - Wiley
T2  - Helvetica Chimica Acta
T1  - Conformations of the Nine-Membered Ring in the B-Nor-5,10-secosteroids. X-Ray and NMR Analysis
VL  - 88
IS  - 10
SP  - 2812
EP  - 2821
DO  - 10.1002/hlca.200590221
ER  - 

@article{
author = "Bjelaković, Mira and Krstić, Natalija and Tinant, Bernard and Kalvoda, Jaroslav and Csanadi, Janos and Pavlović, Vladimir D.",
year = "2005",
abstract = "The conformations of (Z)‐ and (E)‐5‐oxo‐B‐nor‐5,10‐secocholest‐1(10)‐en‐3β‐yl acetates (2 and 3, resp.) were examined by a combination of X‐ray crystallographic analysis and NMR spectroscopy, with emphasis on the geometry of the cyclononenone moiety. The 1H‐ and 13C‐NMR spectra showed that the unsaturated nine‐membered ring of (E)‐isomer 3 in C6D6 and (D6)acetone solution exists in a sole conformation of type B1, which is similar to its solid‐state conformation. The (Z)‐isomer 2 in C6D6, CDCl3, and (D6)acetone solution, however, exists in two conformational forms of different families, with different orientation of the carbonyl group, the predominant form (85%) corresponding to the conformation of type A1 and the minor (15%) to the conformation A2 present also in the crystalline state. In this solid‐state conformations of the nine‐membered ring of both compounds, the 19‐Me and 5‐oxo groups are ‘β’‐oriented. The NMR analysis suggests that the nine‐membered ring of 4 has a conformation of type C1 in CDCl3 solution.",
publisher = "Wiley",
journal = "Helvetica Chimica Acta",
title = "Conformations of the Nine-Membered Ring in the B-Nor-5,10-secosteroids. X-Ray and NMR Analysis",
volume = "88",
number = "10",
pages = "2812-2821",
doi = "10.1002/hlca.200590221"
}

Bjelaković, M., Krstić, N., Tinant, B., Kalvoda, J., Csanadi, J.,& Pavlović, Vladimir D.. (2005). Conformations of the Nine-Membered Ring in the B-Nor-5,10-secosteroids. X-Ray and NMR Analysis. in Helvetica Chimica Acta
Wiley., 88(10), 2812-2821.
https://doi.org/10.1002/hlca.200590221

Bjelaković M, Krstić N, Tinant B, Kalvoda J, Csanadi J, Pavlović V. Conformations of the Nine-Membered Ring in the B-Nor-5,10-secosteroids. X-Ray and NMR Analysis. in Helvetica Chimica Acta. 2005;88(10):2812-2821.
doi:10.1002/hlca.200590221 .

Bjelaković, Mira, Krstić, Natalija, Tinant, Bernard, Kalvoda, Jaroslav, Csanadi, Janos, Pavlović, Vladimir D., "Conformations of the Nine-Membered Ring in the B-Nor-5,10-secosteroids. X-Ray and NMR Analysis" in Helvetica Chimica Acta, 88, no. 10 (2005):2812-2821,
https://doi.org/10.1002/hlca.200590221 . .

TY  - JOUR
AU  - Bjelaković, Mira
AU  - Lorenc, Ljubinka
AU  - Pavlović, Vladimir D.
AU  - Tinant, Bernard
AU  - Declercq, Jean-Paul
AU  - Kalvoda, Jaroslav
PY  - 2003
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4187
AB  - Oxidations of 5α‐hydroxy‐B‐norcholestan‐3β‐yl acetate (8) with Pb(OAc)4 under thermal or photolytic conditions or in the presence of iodine afforded only complex mixtures of compounds. However, the HgO/I2 version of the hypoiodite reaction gave as the primary products the stereoisomeric (Z)‐ and (E)‐1(10)‐unsaturated 5,10‐seco B‐nor‐derivatives 10 and 11, and the stereoisomeric (5R,10R)‐ and (5S,10S)‐acetals 14 and 15 (Scheme 4). Further reaction of these compounds under conditions of their formation afforded, in addition, the A‐nor 1,5‐cyclization products 13 and 16 (from 10) and 12 (from 11) (see also Scheme 6) and the 6‐iodo‐5,6‐secolactones 17 and 19 (from 14 and 15, resp.) and 4‐iodo‐4,5‐secolactone 18 (from 15) (see also Scheme 7). Oxidations of 5β‐hydroxy‐B‐norcholestan‐3β‐yl acetate (9) with both hypoiodite‐forming reagents (Pb(OAc)4/I2 and HgO/I2) proceeded similarly to the HgO/I2 reaction of the corresponding 5α‐hydroxy analogue 8. Photolytic Pb(OAc)4 oxidation of 9 afforded, in addition to the (Z)‐ and (E)‐5,10‐seco 1(10)‐unsaturated ketones 10 and 11, their isomeric 5,10‐seco 10(19)‐unsaturated ketone 22, the acetal 5‐acetate 21, and 5β,19‐epoxy derivative 23 (Scheme 9). Exceptionally, in the thermal Pb(OAc)4 oxidation of 9, the 5,10‐seco ketones 10, 11, and 22 were not formed, the only reaction being the stereoselective formation of the 5,10‐ethers with the β‐oriented epoxy bridge, i.e. the (10R)‐enol ether 20 and (5S,10R)‐acetal 5‐acetate 21 (Scheme 8). Possible mechanistic interpretations of the above transformations are discussed.
PB  - Wiley
T2  - Helvetica Chimica Acta
T1  - Oxidative Fragmentations of the 5-alpha and 5-beta-Hydroxy-B-norcholestan-3-beta-yl Acetates
VL  - 86
IS  - 6
SP  - 2121
EP  - 2135
DO  - 10.1002/hlca.200390169
ER  - 

@article{
author = "Bjelaković, Mira and Lorenc, Ljubinka and Pavlović, Vladimir D. and Tinant, Bernard and Declercq, Jean-Paul and Kalvoda, Jaroslav",
year = "2003",
abstract = "Oxidations of 5α‐hydroxy‐B‐norcholestan‐3β‐yl acetate (8) with Pb(OAc)4 under thermal or photolytic conditions or in the presence of iodine afforded only complex mixtures of compounds. However, the HgO/I2 version of the hypoiodite reaction gave as the primary products the stereoisomeric (Z)‐ and (E)‐1(10)‐unsaturated 5,10‐seco B‐nor‐derivatives 10 and 11, and the stereoisomeric (5R,10R)‐ and (5S,10S)‐acetals 14 and 15 (Scheme 4). Further reaction of these compounds under conditions of their formation afforded, in addition, the A‐nor 1,5‐cyclization products 13 and 16 (from 10) and 12 (from 11) (see also Scheme 6) and the 6‐iodo‐5,6‐secolactones 17 and 19 (from 14 and 15, resp.) and 4‐iodo‐4,5‐secolactone 18 (from 15) (see also Scheme 7). Oxidations of 5β‐hydroxy‐B‐norcholestan‐3β‐yl acetate (9) with both hypoiodite‐forming reagents (Pb(OAc)4/I2 and HgO/I2) proceeded similarly to the HgO/I2 reaction of the corresponding 5α‐hydroxy analogue 8. Photolytic Pb(OAc)4 oxidation of 9 afforded, in addition to the (Z)‐ and (E)‐5,10‐seco 1(10)‐unsaturated ketones 10 and 11, their isomeric 5,10‐seco 10(19)‐unsaturated ketone 22, the acetal 5‐acetate 21, and 5β,19‐epoxy derivative 23 (Scheme 9). Exceptionally, in the thermal Pb(OAc)4 oxidation of 9, the 5,10‐seco ketones 10, 11, and 22 were not formed, the only reaction being the stereoselective formation of the 5,10‐ethers with the β‐oriented epoxy bridge, i.e. the (10R)‐enol ether 20 and (5S,10R)‐acetal 5‐acetate 21 (Scheme 8). Possible mechanistic interpretations of the above transformations are discussed.",
publisher = "Wiley",
journal = "Helvetica Chimica Acta",
title = "Oxidative Fragmentations of the 5-alpha and 5-beta-Hydroxy-B-norcholestan-3-beta-yl Acetates",
volume = "86",
number = "6",
pages = "2121-2135",
doi = "10.1002/hlca.200390169"
}

Bjelaković, M., Lorenc, L., Pavlović, Vladimir D., Tinant, B., Declercq, J.,& Kalvoda, J.. (2003). Oxidative Fragmentations of the 5-alpha and 5-beta-Hydroxy-B-norcholestan-3-beta-yl Acetates. in Helvetica Chimica Acta
Wiley., 86(6), 2121-2135.
https://doi.org/10.1002/hlca.200390169

Bjelaković M, Lorenc L, Pavlović V, Tinant B, Declercq J, Kalvoda J. Oxidative Fragmentations of the 5-alpha and 5-beta-Hydroxy-B-norcholestan-3-beta-yl Acetates. in Helvetica Chimica Acta. 2003;86(6):2121-2135.
doi:10.1002/hlca.200390169 .

Bjelaković, Mira, Lorenc, Ljubinka, Pavlović, Vladimir D., Tinant, Bernard, Declercq, Jean-Paul, Kalvoda, Jaroslav, "Oxidative Fragmentations of the 5-alpha and 5-beta-Hydroxy-B-norcholestan-3-beta-yl Acetates" in Helvetica Chimica Acta, 86, no. 6 (2003):2121-2135,
https://doi.org/10.1002/hlca.200390169 . .

TY  - JOUR
AU  - Bjelaković, Mira
AU  - Lorenc, Ljubinka
AU  - Pavlović, Vladimir D.
AU  - Mihailović, Milhailo Lj.
AU  - Tinant, Bernard
AU  - Declercq, Jean-Paul
AU  - Kalvoda, Jaroslav
PY  - 1999
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4184
AB  - Oxidations of 14α‐hydroxy‐5α‐cholestan‐3β‐yl acetate (5) with lead tetraacetate under thermal or photolytic conditions or in the presence of iodine proceed mainly by fragmentation of the C(13)−C(14) bond to give as the primary products the 13,18‐didehydro‐13,14‐seco derivative 6 and the (E )‐Δ12‐13,14‐seco ketone 11, respectively. Further transformations of these compounds under conditions of their formation afforded, in addition, the acetoxy derivatives 7 – 9 (from 6), and the D‐homo‐C‐nor compound 12 and (12R,13R)‐epoxide 13 (from 11). Unexpectedly, the photolytic lead‐tetraacetate oxidation of 5 resulted partly (to ca. 20%) in a reversible fragmentation involving scission and recombination of the C(8)−C(14) bond followed by formation of the 14β,22‐ether 10. Possible mechanisms for the observed transformations are discussed.
PB  - Wiley
T2  - Helvetica Chimica Acta
T1  - 13,14-Seco-steroids: A New Type of Modified Steroids Containing a Nine-Membered Ring
VL  - 82
IS  - 5
SP  - 707
EP  - 721
DO  - 10.1002/(SICI)1522-2675(19990505)82:5<707::AID-HLCA707>3.0.CO;2-O
ER  - 

@article{
author = "Bjelaković, Mira and Lorenc, Ljubinka and Pavlović, Vladimir D. and Mihailović, Milhailo Lj. and Tinant, Bernard and Declercq, Jean-Paul and Kalvoda, Jaroslav",
year = "1999",
abstract = "Oxidations of 14α‐hydroxy‐5α‐cholestan‐3β‐yl acetate (5) with lead tetraacetate under thermal or photolytic conditions or in the presence of iodine proceed mainly by fragmentation of the C(13)−C(14) bond to give as the primary products the 13,18‐didehydro‐13,14‐seco derivative 6 and the (E )‐Δ12‐13,14‐seco ketone 11, respectively. Further transformations of these compounds under conditions of their formation afforded, in addition, the acetoxy derivatives 7 – 9 (from 6), and the D‐homo‐C‐nor compound 12 and (12R,13R)‐epoxide 13 (from 11). Unexpectedly, the photolytic lead‐tetraacetate oxidation of 5 resulted partly (to ca. 20%) in a reversible fragmentation involving scission and recombination of the C(8)−C(14) bond followed by formation of the 14β,22‐ether 10. Possible mechanisms for the observed transformations are discussed.",
publisher = "Wiley",
journal = "Helvetica Chimica Acta",
title = "13,14-Seco-steroids: A New Type of Modified Steroids Containing a Nine-Membered Ring",
volume = "82",
number = "5",
pages = "707-721",
doi = "10.1002/(SICI)1522-2675(19990505)82:5<707::AID-HLCA707>3.0.CO;2-O"
}

Bjelaković, M., Lorenc, L., Pavlović, Vladimir D., Mihailović, M. Lj., Tinant, B., Declercq, J.,& Kalvoda, J.. (1999). 13,14-Seco-steroids: A New Type of Modified Steroids Containing a Nine-Membered Ring. in Helvetica Chimica Acta
Wiley., 82(5), 707-721.
https://doi.org/10.1002/(SICI)1522-2675(19990505)82:5<707::AID-HLCA707>3.0.CO;2-O

Bjelaković M, Lorenc L, Pavlović V, Mihailović ML, Tinant B, Declercq J, Kalvoda J. 13,14-Seco-steroids: A New Type of Modified Steroids Containing a Nine-Membered Ring. in Helvetica Chimica Acta. 1999;82(5):707-721.
doi:10.1002/(SICI)1522-2675(19990505)82:5<707::AID-HLCA707>3.0.CO;2-O .

Bjelaković, Mira, Lorenc, Ljubinka, Pavlović, Vladimir D., Mihailović, Milhailo Lj., Tinant, Bernard, Declercq, Jean-Paul, Kalvoda, Jaroslav, "13,14-Seco-steroids: A New Type of Modified Steroids Containing a Nine-Membered Ring" in Helvetica Chimica Acta, 82, no. 5 (1999):707-721,
https://doi.org/10.1002/(SICI)1522-2675(19990505)82:5<707::AID-HLCA707>3.0.CO;2-O . .

TY  - JOUR
AU  - Kalvoda, Jaroslav
AU  - Grob, Jüren
AU  - Bjelaković, Mira
AU  - Lorenc, Ljubinka
AU  - Mihailović, Milhailo Lj.
PY  - 1997
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4188
AB  - The two structurally similar 20‐phenyl‐ and 20‐(4‐methoxyphenyl)‐11‐(nitrosooxy)pregnan‐20‐ol derivatives 4 and 7 behave differently under photolytic conditions, the former nitrous acid ester affording, as a main product, the benzo‐fused hexacyclic compound 9, and the latter the 21‐nitro derivative 12. Mechanistic aspects of these transformations are discussed.
PB  - Wiley
T2  - Helvetica Chimica Acta
T1  - Photolysis of Steroidal 20-Aryl-Substituted 11-Nitrites
VL  - 80
IS  - 4
SP  - 1221
EP  - 1228
DO  - 10.1002/hlca.19970800419
ER  - 

@article{
author = "Kalvoda, Jaroslav and Grob, Jüren and Bjelaković, Mira and Lorenc, Ljubinka and Mihailović, Milhailo Lj.",
year = "1997",
abstract = "The two structurally similar 20‐phenyl‐ and 20‐(4‐methoxyphenyl)‐11‐(nitrosooxy)pregnan‐20‐ol derivatives 4 and 7 behave differently under photolytic conditions, the former nitrous acid ester affording, as a main product, the benzo‐fused hexacyclic compound 9, and the latter the 21‐nitro derivative 12. Mechanistic aspects of these transformations are discussed.",
publisher = "Wiley",
journal = "Helvetica Chimica Acta",
title = "Photolysis of Steroidal 20-Aryl-Substituted 11-Nitrites",
volume = "80",
number = "4",
pages = "1221-1228",
doi = "10.1002/hlca.19970800419"
}

Kalvoda, J., Grob, J., Bjelaković, M., Lorenc, L.,& Mihailović, M. Lj.. (1997). Photolysis of Steroidal 20-Aryl-Substituted 11-Nitrites. in Helvetica Chimica Acta
Wiley., 80(4), 1221-1228.
https://doi.org/10.1002/hlca.19970800419

Kalvoda J, Grob J, Bjelaković M, Lorenc L, Mihailović ML. Photolysis of Steroidal 20-Aryl-Substituted 11-Nitrites. in Helvetica Chimica Acta. 1997;80(4):1221-1228.
doi:10.1002/hlca.19970800419 .

Kalvoda, Jaroslav, Grob, Jüren, Bjelaković, Mira, Lorenc, Ljubinka, Mihailović, Milhailo Lj., "Photolysis of Steroidal 20-Aryl-Substituted 11-Nitrites" in Helvetica Chimica Acta, 80, no. 4 (1997):1221-1228,
https://doi.org/10.1002/hlca.19970800419 . .

TY  - JOUR
AU  - Lorenc, Ljubinka
AU  - Bondarenko-Gheorghiu, Lidija
AU  - Pavlović, Vladimir B.
AU  - Führer, Hermann
AU  - Kalvoda, Jaroslav
AU  - Mihailović, Milhailo Lj.
PY  - 1992
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4743
AB  - Catalytic hydrogenation of the Δ3‐unsaturated (9R,10 R)‐ and (9S,10 S)‐epoxyenol lactones 3a, b., and 4a, b., respectively, affords, in addition to the expected saturated epoxylactones 5a, b and 7a, b, also open‐chain products, i.e. the diastereoisomeric (9R,10R)‐ and (9S,10S)‐9,10‐expoxy‐8‐oxo‐4,5‐secosteroklastan‐5‐oic acids 6a, b. and 8a, b. Alkaline hydrolysis of the lactone ring of compounds 5 and 7 and subsequent acetylation of the corresponding hydroxy derivatives give as the major products the open‐chain, diasteroisomeric (9R,10R)‐ and (9S,10S)‐4‐acetoxy‐9,10‐epoxy‐methyl esters 9a, b and 11a, b, respectively, and, but only in the androstane series, the tetrahydropyran derivatives 10a and 12a, as the minor components.
PB  - Weinheim : Wiley-VCH Verlag GmbH & Co.
T2  - Helvetica Chimica Acta
T1  - Opening of the Macrocyclic Ring in 5,10:8,9‐Disecosteroids ( = Steroklastanes)
VL  - 75
IS  - 1
SP  - 203
EP  - 209
DO  - 10.1002/hlca.19920750118
ER  - 

@article{
author = "Lorenc, Ljubinka and Bondarenko-Gheorghiu, Lidija and Pavlović, Vladimir B. and Führer, Hermann and Kalvoda, Jaroslav and Mihailović, Milhailo Lj.",
year = "1992",
abstract = "Catalytic hydrogenation of the Δ3‐unsaturated (9R,10 R)‐ and (9S,10 S)‐epoxyenol lactones 3a, b., and 4a, b., respectively, affords, in addition to the expected saturated epoxylactones 5a, b and 7a, b, also open‐chain products, i.e. the diastereoisomeric (9R,10R)‐ and (9S,10S)‐9,10‐expoxy‐8‐oxo‐4,5‐secosteroklastan‐5‐oic acids 6a, b. and 8a, b. Alkaline hydrolysis of the lactone ring of compounds 5 and 7 and subsequent acetylation of the corresponding hydroxy derivatives give as the major products the open‐chain, diasteroisomeric (9R,10R)‐ and (9S,10S)‐4‐acetoxy‐9,10‐epoxy‐methyl esters 9a, b and 11a, b, respectively, and, but only in the androstane series, the tetrahydropyran derivatives 10a and 12a, as the minor components.",
publisher = "Weinheim : Wiley-VCH Verlag GmbH & Co.",
journal = "Helvetica Chimica Acta",
title = "Opening of the Macrocyclic Ring in 5,10:8,9‐Disecosteroids ( = Steroklastanes)",
volume = "75",
number = "1",
pages = "203-209",
doi = "10.1002/hlca.19920750118"
}

Lorenc, L., Bondarenko-Gheorghiu, L., Pavlović, V. B., Führer, H., Kalvoda, J.,& Mihailović, M. Lj.. (1992). Opening of the Macrocyclic Ring in 5,10:8,9‐Disecosteroids ( = Steroklastanes). in Helvetica Chimica Acta
Weinheim : Wiley-VCH Verlag GmbH & Co.., 75(1), 203-209.
https://doi.org/10.1002/hlca.19920750118

Lorenc L, Bondarenko-Gheorghiu L, Pavlović VB, Führer H, Kalvoda J, Mihailović ML. Opening of the Macrocyclic Ring in 5,10:8,9‐Disecosteroids ( = Steroklastanes). in Helvetica Chimica Acta. 1992;75(1):203-209.
doi:10.1002/hlca.19920750118 .

Lorenc, Ljubinka, Bondarenko-Gheorghiu, Lidija, Pavlović, Vladimir B., Führer, Hermann, Kalvoda, Jaroslav, Mihailović, Milhailo Lj., "Opening of the Macrocyclic Ring in 5,10:8,9‐Disecosteroids ( = Steroklastanes)" in Helvetica Chimica Acta, 75, no. 1 (1992):203-209,
https://doi.org/10.1002/hlca.19920750118 . .

TY  - JOUR
AU  - Lorenc, Ljubinka B.
AU  - Pavlović, Vladimir D.
AU  - Mihailovíć, Mihailo  Lj.
AU  - Kalvoda, Jaroslav
AU  - Führer, Hermann
PY  - 1991
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4393
AB  - UV irradiation of the unsaturated (E)‐5,10‐secosteroidal ketones 1 and 6 results, in addition to (E/Z)‐isomerization, in an intramolecular Pateino‐Büchi reaction and, in the case of 1, in transannular cyclization (along with AcOH elimination). The stereochemistry of the observed intramolecular photoprocesses can be explained in terms of ground‐state conformations of the (E)‐seco‐ketones 1 and 6 in solution.
PB  - Wiley - VCH Verlag GmbH & Co
T2  - Helvetica Chimica Acta
T1  - Synthesis, structure, and reactivity of secosteroids containing a medium‐sized ring. Part 32. Conformations and photochemical reactivity of some unsaturated 5,10‐secosteroidal ketones
VL  - 74
IS  - 7
SP  - 1459
EP  - 1463
DO  - 10.1002/hlca.19910740709
ER  - 

@article{
author = "Lorenc, Ljubinka B. and Pavlović, Vladimir D. and Mihailovíć, Mihailo  Lj. and Kalvoda, Jaroslav and Führer, Hermann",
year = "1991",
abstract = "UV irradiation of the unsaturated (E)‐5,10‐secosteroidal ketones 1 and 6 results, in addition to (E/Z)‐isomerization, in an intramolecular Pateino‐Büchi reaction and, in the case of 1, in transannular cyclization (along with AcOH elimination). The stereochemistry of the observed intramolecular photoprocesses can be explained in terms of ground‐state conformations of the (E)‐seco‐ketones 1 and 6 in solution.",
publisher = "Wiley - VCH Verlag GmbH & Co",
journal = "Helvetica Chimica Acta",
title = "Synthesis, structure, and reactivity of secosteroids containing a medium‐sized ring. Part 32. Conformations and photochemical reactivity of some unsaturated 5,10‐secosteroidal ketones",
volume = "74",
number = "7",
pages = "1459-1463",
doi = "10.1002/hlca.19910740709"
}

Lorenc, L. B., Pavlović, V. D., Mihailovíć, Mihailo  Lj., Kalvoda, J.,& Führer, H.. (1991). Synthesis, structure, and reactivity of secosteroids containing a medium‐sized ring. Part 32. Conformations and photochemical reactivity of some unsaturated 5,10‐secosteroidal ketones. in Helvetica Chimica Acta
Wiley - VCH Verlag GmbH & Co., 74(7), 1459-1463.
https://doi.org/10.1002/hlca.19910740709

Lorenc LB, Pavlović VD, Mihailovíć, Mihailo  Lj., Kalvoda J, Führer H. Synthesis, structure, and reactivity of secosteroids containing a medium‐sized ring. Part 32. Conformations and photochemical reactivity of some unsaturated 5,10‐secosteroidal ketones. in Helvetica Chimica Acta. 1991;74(7):1459-1463.
doi:10.1002/hlca.19910740709 .

Lorenc, Ljubinka B., Pavlović, Vladimir D., Mihailovíć, Mihailo  Lj., Kalvoda, Jaroslav, Führer, Hermann, "Synthesis, structure, and reactivity of secosteroids containing a medium‐sized ring. Part 32. Conformations and photochemical reactivity of some unsaturated 5,10‐secosteroidal ketones" in Helvetica Chimica Acta, 74, no. 7 (1991):1459-1463,
https://doi.org/10.1002/hlca.19910740709 . .