Agronomic Investigation of Spray Dispersion of Metal-Based Nanoparticles on Sunflowers in Real-World Environments

In environmental and agronomic settings, even minor imbalances can trigger a range of unpredicted responses. Despite the widespread use of metal-based nanoparticles (NPs) and new bio-nanofertilizers, their impact on crop production is absent in the literature. Therefore, our research is focused on the agronomic effect of spray application of gold nanoparticles anchored to SiO₂ mesoporous silica (AuSi-NPs), zinc oxide nanoparticles (ZnO-NPs), and iron oxide nanoparticles (Fe₃O₄-NPs) on sunflowers under real-world environments. Our findings revealed that the biosynthetically prepared AuSi-NPs and ZnO-NPs were highly effective in enhancing sunflower seasonal physiology, e.g., the value of the NDVI index increased from 0.012 to 0.025 after AuSi-NPs application. The distribution of leaf trichomes improved and the grain yield increased from 2.47 t ha^-1 to 3.29 t ha^-1 after ZnO-NPs application. AuSi-NPs treatment resulted in a higher content of essential linoleic acid (54.37%) when compared to the NPs-free control (51.57%), which had a higher determined oleic acid. No NPs or residual translocated metals were detected in the fully ripe sunflower seeds, except for slightly higher silica content after the AuSi-NPs treatment. Additionally, AuSi-NPs and NPs-free control showed wide insect biodiversity while ZnO-NPs treatment had the lowest value of phosphorus as anti-nutrient. Contradictory but insignificant effect on physiology, yield, and insect biodiversity was observed in Fe₃O₄-NPs treatment. Therefore, further studies are needed to fully understand the long-term environmental and agricultural sustainability of NPs applications.

Effects of Foliar Application of ZnO Nanoparticles on Lentil Production, Stress Level and Nutritional Seed Quality under Field Conditions

Nanotechnology offers new opportunities for the development of novel materials and strategies that improve technology and industry. This applies especially to agriculture, and our previous field studies have indicated that zinc oxide nanoparticles provide promising nano-fertilizer dispersion in sustainable agriculture. However, little is known about the precise ZnO-NP effects on legumes. Herein, 1 mg·L−1 ZnO-NP spray was dispersed on lentil plants to establish the direct NP effects on lentil production, seed nutritional quality, and stress response under field conditions. Although ZnO-NP exposure positively affected yield, thousand-seed weight and the number of pods per plant, there was no statistically significant difference in nutrient and anti-nutrient content in treated and untreated plant seeds. In contrast, the lentil water stress level was affected, and the stress response resulted in statistically significant changes in stomatal conductance, crop water stress index, and plant temperature. Foliar application of low ZnO-NP concentrations therefore proved promising in increasing crop production under field conditions, and this confirms ZnO-NP use as a viable strategy for sustainable agriculture.

Effects of selenium on macro- and micro nutrients and selected qualitative parameters of oat (Avena sativa L.)

The article deals with the effect of foliar Se application on macro-and micro-elements and selected quantitative parameters (the content of ash, starch, and fat) in oat grains. The three-year experiments were carried out on Research and Breeding Station Vígľaš – Pstruša in the years 2014, 2015, 2016. The used oat variety was Valentin. The experiment was performed by a block method within a parcel size of 10 square meters (8 x 1.25 m) with the span of rows amounting to 0.125 m in four replications. Alfalfa was grown as forecrop. A potato and wheat production area (III-C2) with a height of 375 m above the sea level. The experimental area is characterized by warm, slightly wet weather with an average annual temperature of 7.8 °C and average annual precipitations of 666 mm. Basic fertilizing was planned before the sowing in the form of 100 kg of Ammonium nitrate containing dolomite (27% N), 100 kg of 60% KCl (60% of K2O), and100 kg of MAP (Monoammonium phosphate 12% N and 52% P2O5). Selenium was foliar applied in doses 25 g and 50 g Se per hectare in a solution form of sodium selenate (Na2SeO4). The harvest was realized by a small plot harvester in BBCH 91. The results of the experiments showed a statistically non-significant effect on microelements and most macroelements. Only sulfur content in oat grains was statistically significantly influenced by Se foliar treatment. The contents of ash, starch, and fat in oat grains were monitored, which showed statistically significant effect only in fat. Se content in grains showed a statistically significant increase by both Se foliar treatments.

Effect of Foliar Spray Application of Zinc Oxide Nanoparticles on Quantitative, Nutritional, and Physiological Parameters of Foxtail Millet (Setaria italica L.) under Field Conditions

It has been shown that the foliar application of inorganic nano-materials on cereal plants during their growth cycle enhances the rate of plant productivity by providing a micro-nutrient source. We therefore studied the effects of foliarly applied ZnO nanoparticles (ZnO NPs) on Setaria italica L. foxtail millet's quantitative, nutritional, and physiological parameters. Scanning electron microscopy showed that the ZnO NPs have an average particle size under 20 nm and dominant spherically shaped morphology. Energy dispersive X-ray spectrometry then confirmed ZnO NP homogeneity, and X-ray diffraction verified their high crystalline and wurtzite-structure symmetry. Although plant height, thousand grain weight, and grain yield quantitative parameters did not differ statistically between ZnO NP-treated and untreated plants, the ZnO NP-treated plant grains had significantly higher oil and total nitrogen contents and significantly lower crop water stress index (CWSI). This highlights that the slow-releasing nano-fertilizer improves plant physiological properties and various grain nutritional parameters, and its application is therefore especially beneficial for progressive nanomaterial-based industries.

Synthesis of 5α-androstane-3α,17β-diol 17-O-glucuronide histaminyl conjugate for immunoassays

Simple method of preparation of 5α-androstane-3α,17β-diol 17-O-glucuronide N-histaminyl amide was developed for the construction of immunoanalytical kit. Improved method of glucuronide derivative synthesis was used, followed by hydroxybenzotriazole-dicyclohexylcarbodiimide coupling with histamine.

Novel approach to the preparation of hemisuccinates of steroids bearing tertiary alcohol group

17β-O-Hemisuccinates of typical representatives of Anabolic-Androgenic Steroids, 17β-hydroxy-17-methylandrostan-4-en-3-one, 17β-hydroxy-17-methyl-2-oxa-5α-androstan-3-one, 17β-hydroxy-17-methyl-5α-androstano-[3,2-c]pyrazole, were prepared. Several methods for the hemisuccinate preparation were tested. The indirect method using 1-ethyl-3-(dimethylaminopropyl)carbodiimide coupling reagent to form an ester bond of steroid with 2-(trimethylsilyl)ethyl hydrogen butanedioate was finally applied. Using the selectively removable protecting group, the desired hemisuccinates of steroids bearing tertiary alcohol group were obtained.

Azido analogs of neuroactive steroids

Analogs of pregnanolone (3α-hydroxy-5β-pregnan-20-one), modified in position 17 were prepared. Compounds with 20-keto pregnane side chain replaced completely by azide (17α- and 17β-azido-5β-androstan-3α-ol), compounds with its part replaced (20-azido-21-nor-5β-pregnan-3α-ol), and compounds with keto group only replaced ((20R)- and (20S)-20-azido-5β-pregnan-3α-ol) were synthesized using tosylate displacements with sodium azide or Mitsunobu reaction with azoimide. All five azido steroids were converted into corresponding sulfates. Subsequent tests for inhibition of glutamate induced response on NMDA receptors revealed that modification of pregnanolone sulfate side chain with azide did not disturb the activity and some of sulfates tested were more active than parent compound.

Synthetic Approach to 5α-Pregnanolone 19-[O-(Carboxymethyl)oxime] Derivatives

Syntheses of 5α-pregnanolone derivatives (3-hydroxy-5α-pregnan-20-ones) with 3α- and 3β-configuration and 19-[O-(carboxymethyl)oxime] group were developed, starting from 19-hydroxy-20-oxopregn-5-en-3β-yl acetate. After catalytic hydrogenation, acetylation and ketone protection, the acetyl in position 3 was removed. To obtain the 3α-derivative, nitrite epimerization of the intermediate tosylate was performed before the introduction of methoxymethyl protecting group, while the 3β-derivative was protected directly. In both series, deacetylation, oxidation to an aldehyde andO-(carboxymethyl)hydroxylamine condenzation followed. Conversion to the methyl ester, simultaneous deprotection of positions 3 and 20, and alkaline hydrolysis gave the corresponding 19-[O-(carboxymethyl)oximes]. The nine- and ten-step syntheses described herein (yields 19.5 and 7.3%, respectively) gave the target compounds, designed as haptens for immunological use.

Linear Chaining of Etienic Acid Derivatives with the Amide Bond. Synthesis of Oligomeric Steroids

Synthesis of linear molecules containing two to four steroid units connected with the amide bonds was developed. As a repeating unit, 3β-hydroxyandrost-5-ene-17β-carboxylic acid (etienic acid) was used. An active ester of this acid with N-hydroxysuccinimide and its 3-azido analogue were prepared and methods for the preparation of higher oligomers were studied.

Synthesis of Symmetrical Bis-Steroid Pyrazines Connected via D-Rings

Bis-steroid pyrazines fused through rings D of the steroid skeleton were synthesized. Methods for the preparation of the corresponding rings A fused derivatives (cephalostatin type) were checked on simple androstanes and then a symmetrical D fused analogue, 5α-androstano[16'',17''-5',6']pyrazino[2',3'-16,17]-5α-androstane-3β,3''b-diol, was prepared. Partially substituted bis-steroid pyrazines in both series were prepared and their use for the preparation of higher fused compounds was discussed. No significant cytostatic activity was found on parent bis-steroid pyrazines both A and D fused.

Addition of Azoimide to Unsaturated Ketones in the Steroid Series. Synthesis of N-(17β-Hydroxy-3-oxo-5α-androstan-15β-yl)succinamoic Acid and Its Evaluation as Hapten for Dihydrotestosterone Immunoanalysis

Addition of azoimide to 17-oxoandrosta-5,15-dien-3β-yl acetate or 17-oxo-5α-androst-15-en-3β-yl acetate gave in both cases corresponding 15β-azido derivatives. 15β-Azido-17-oxo-5α-androstan-3β-yl acetate was selectively reduced to 17β-hydroxy derivative and protected as methoxymethyl ether. Subsequent reduction of azide group and condensation with methyl hydrogen succinate gave a protected succinylamino derivative. Deacetylation and oxidation then led to dihydrotestosterone (DHT) series. Successive removal of protecting groups gave N-(17β-hydroxy-3-oxo-5α-androstan-15β-yl)succinamoic acid, an experimental hapten for DHT. Its conjugate with bovine serum albumin was used for immunization of rabbits and corresponding antisera were evaluated in RIA using [3H]-DHT as a tracer. The results are comparable with standard kits based on antisera generated using DHT derivatives with connecting bridge in position 7.

Preparation of 7-[O-(Carboxymethyl)oxime] Derivatives of Dehydroepiandrosterone and Pregnenolone

Novel simple syntheses of 7-(O-carboxymethyloxime) derivatives of 3β-hydroxyandrost-5-en-17-one (dehydroepiandrosterone) and of 3β-hydroxypregn-5-en-20-one (pregnenolone) are reported. In the first one, 17-oxoandrost-5-en-3β-yl acetate was oxidized to give the 7,17-dione which was then selectively reduced in the position 17. Oximation, reoxidation, and deacetylation yielded the desired oxime. The second synthesis started with (20R)-pregn-5-ene-3β,20-diol 3-acetate which was converted to the 20-nitrate, oxidized to the C-7 ketone, oximated, partially deprotected in position 20, reoxidized, and deacetylated. Both the 7-(O-carboxymethyloxime) derivatives have been devised as immunoassay components.

Preparation of β-D-Glucopyranosyl Derivatives of 1,6:2,3- and 1,6:3,4-Dianhydro-β-D-hexopyranoses and Their 1H and 13C NMR Spectra

The corresponding acetylated and free 2-O- and 4-O-glucosyl derivatives of dianhydrohexoses Ib - VIIb and Ic - VIIc have been obtained by the reactions of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (IX) with 1,6:3,4- and 1,6:2,3-dianhydro-β-D-hexopyranoses (Ia - VIIa). Structure of the products and the effects of glycosylation upon chemical shifts and conformations of the disaccharides prepared have been studied using 1H and 13C NMR spectra.

17-(O-(2-Carboxyethyl)oxime) Derivatives of Androstanes of 3-Hydroxy-5α-, -5β-, -5-ene and 3-Oxo-4-ene Series

Androstane 17-(O-(2-carboxyethyl)oxime) derivatives were prepared either by the reaction of 17-keto derivatives with corresponding substituted hydroxylamine or by the addition of 17-oximino derivatives to the alkyl acrylate and subsequent hydrolysis. Oxidation of the hydroxy group in position 3 in derivatives of this type was performed either by the Oppenauer reaction, transforming 5-ene derivatives into 3-oxo-4-enes, or with Jones reagent in the case of saturated 5α- or 5β-derivatives. Configuration 17E in the whole series of oximes was confirmed by the 1H and 13C NMR spectroscopy.

Construction of the Side-Chain in 14β-Androst-5-ene Derivatives. Preparation of 14β-Pregnenolone

Stepwise side-chain construction schemes leading to pregnane derivatives were tested in the 14β-androst-5-ene series. 6β-Methoxy-3α,5-cyclo-5α,14β-androstan-17-one (I) gave after methylenation and hydroboration the 17α-hydroxymethyl derivative III. Subsequent oxidation to the aldehyde VI, Grignard reaction with methylmagnesium iodide, and reoxidation led to the ketone VII and to the isomeric 17β-derivative VIII as a minor product. Final i-steroid cleavage of VII furnished the known 14β,17α-pregnenolone IX; the minor product VIII gave the 17β-isomer X. Alternatively, the ketone X was prepared from 6β-methoxy-3α,5-cyclo-5α,14β-androstan-17α-ol p-toluenesulfonate (XI) by cyanide substitution, diisobutylaluminum hydride reduction to the aldehyde XIV, and further as described for IX. The mass and NMR spectra of the four pregnenolone derivatives IX, X, XVIII, and XIX, isomeric in positions 14 and 17, were studied.

Preparation of (17E)-3β-Hydroxyandrost-5-en-17-one (O-Carboxymethyl)oxime Derivatives with Short Peptide Chain

17-(O-Carboxymethyl)oxime (CMO) derivatives of 3β-acetoxy-, 3β-methoxymethoxy-, 3β-hydroxyandrost-5-en-17-one, and of -androst-4-ene-3,17-dione (IV - VI, XXIX) were prepared. Methods for the attachment of amino acids to the CMO group and for the peptide chain elongation were tested. The mixed anhydride method was used for linking the first amino acid unit (Gly, βAla, or Gly-Gly dipeptide), further units were added by the N-hydroxysuccinimide method. Compounds with one to four amino acids were prepared. This concept is suitable for the preparation of haptens with variable bridge length for the binding studies.

Acrylate Side Chain Derivatives of 5β-Steroids

Steroids with 5β-configuration and acrylate 17β-side chain, namely (20E)-3β-hydroxy-5β-pregnane-21-carboxylate (XVI), its 3α-epimer XXVI, and homological ethyl ester XVIII were prepared from 3β-(2-tetrahydropyranyloxy)-21-norpregn-5-en-20-ol (I). The stereoselectivity of key steps was checked. Whereas hydrogenation of 4-en-3-one derivative IV gave exclusively 5β-derivative VI, the subsequent borohydride reduction yielded 3β- and 3α-hydroxy derivatives VII and XI in 1 : 4 ratio. The 3-hydroxy derivatives prepared (XVI, XVIII, and XXVI) were converted to the corresponding hemisuccinates (XX and XXVIII) and β-D-glucopyranosides (XXII, XVIV, and XXX) for latter use in biological studies.

Glucosylation of Some Steroidal 17-Hydroxy Derivatives

Eight 17-monoglucosides derived from androst-5-ene-3,17-diol, 14β-androst-5-ene-3,17-diol, 5β-androstane-3,17-diol and estradiol derivatives differing in configuration in the positions 17 and 3, have been prepared. The silver silicate - catalyzed glycosylation with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide gave 43-72% of the corresponding peracetylated β-D-glucopyranosides. The starting selectively protected 5β-androstane-3,17-diol derivatives were synthesized by a procedure utilizing orthogonality of the pivalate, acetate and nitrate protecting groups.

Glycosylation of steroids with silver silicate and 2-deoxy-2-fluoro-α-D-glucopyranosyl bromide triacetate

Glycosylation with the title glycosyl bromide I in 1,2-dichloroethane in the presence of silver silicate and a molecular sieves afforded mixtures of 3,4,6-tri-O-acetyl-2-deoxy-2-fluoro-α- and β-D-glucopyranosides (V-X), derived from ethyl (20E)-3β-hydroxy-24-nor-5,20(22)-choladien-23-oate (II), (20E)-3β-hydroxy-5β-pregn-20-ene-21-carboxylate (III) and 3β, 14-dihydroxy-5β, 14β-card-20(22)-enolide (IV, digitoxigenin), in which the β-anomers predominated. Separation and deacetylation furnished the corresponding 2-deoxy-2-fluoroglucosides XI-XVI.

β-Glucosides of steroidal unsaturated nitriles

Reaction of 3β-methoxymethoxy-5-pregnen-20-one (Ia) with diethyl cyanomethylphosphonate and subsequent removal of the protecting group afforded (20E)-3β-hydroxy-24-norchola-5,20(22)-diene-23-nitrile (IIIa). Besides the analogous derivative IIIb with another double bond in position 14, the fully saturated compounds IIIc and IIId with configuration 5α and 5β, respectively, were prepared similarly. Silver silicate-catalyzed glycosylation of IIIa-IIId with tetra-O-acetyl-α-D-glucopyranosyl bromide gave β-D-glucopyranosides IVa-IVd in 77-89% yield. A parallel series of hemisuccinates VIa-VId was prepared in 64-81% yields by reaction of IIIa-IIId with 2-(trimethylsilyl)ethyl hydrogen butanedioate followed by deblocking with tetrabutylammonium fluoride. The glucoside IVa was prepared also by an alternative reaction pathway starting from 3β-hydroxy-5-pregnen-20-one (VIII). Compound VIII was converted in 80% yield into the glucoside IX which, after protection as the tetra-O-(trimethylsilyl)derivative XII, was treated with diethyl cyanomethylphosphonate.

Steroids with the β-crotonate (2-butenoate) side chain

Ethyl (20E)-3β-methoxymethoxy-24-nor-5,20(22)-choladien-23-oate (Va) and analogous derivatives with 5α,5β and Δ5,14 steroid moiety (Vb,Vc and Vd, respectively) were prepared by Wittig-Horner reaction of the corresponding ketones IIa-IId with diethyl ethoxycarbonylmethylphosphonate. In this case the reaction affords exclusively the (E)-isomers, in contrast with the Peterson reaction with lithium salt of ethyl 2-(trimethylsilyl)acetate which gives a mixture of (E)- and (Z)-isomers at the Δ20(22) double bond. The structure of the products was confirmed by 1H NMR and 13C NMR spectroscopy. The crotonates Va-Vd were further converted into the 3-O-succinyl derivatives VIIIa-VIIId.

Infrared spectra of compounds with the methoxymethyl protecting group

Infrared spectra of a series of compounds containing the CH3OCH2O- (MOM-O-) group have been studied. All the spectra exhibit three characteristic strong absorption bands due to coupled stretching vibrations of C-O-C-O-C grouping in the region 1 200 - 1 000 cm-1.

New method of preparation of cardioglycoside hemisuccinates

An indirect method for preparation of hemisuccinates (hydrogen butanedioates) is described, consisting in reaction of hydroxy derivatives with 2-(trimethylsilyl)ethyl hemisuccinate (I) followed by removal of the 2-(trimethylsilyl)ethyl group from the mixed succinate with tetrabutylammonium fluoride. It has been applied to the synthesis of hemisuccinates derived from cholesterol (II), (20E)-21-methoxycarbonylpregna-5,20-dien-3β-ol (V), digitoxigenin (XII), digitoxin (XV) and digoxin (XVIII). The method, however, is not suitable for the preparation of estrone hemisuccinate X which is cleaved with tetrabutylammonium fluoride to give estrone(VIII).

Azido derivatives of 1,6-anhydro-β-D-hexopyranoses corresponding to 3-deoxy- and 4-deoxy-D-glucosamine

Nucleophilic substitution of the tosyloxy group in 1,6-anhydro-3-deoxy-2-O-p-toluenesulfonyl-β-D-arabino-hexopyranose (II) with lithium azide gave derivative V which was acetolysed and deacetylated to 2-azido-2,3-dideoxy-D-ribo-hexose (IX). The oxirane ring in 1,6 : 2,3-dianhydro-4-deoxy-β-D-lyxo-hexopyranose (XII) was opened using lithium azide and the mixture of 2- and 3-azido derivatives XIII of D-xylo and XIV of D-arabino configuration formed was separated by an extraction procedure after previous selective trimethylsilylation. Azido derivative XIII was converted to 2-azido-2,4-dideoxy-D-xylo-hexose (XIX) on acetolysis and deacetylation. Hydrogenation of azido derivatives IX and XIX on palladium on charcoal and subsequent N-acetylation gave corresponding 3- and 4-deoxy derivatives of D-glucosamine, XI and XXI.

Synthesis of 17β-[4-(1,3-thiazolyl)]androstane 3β-hemisuccinate and glycoside

The protected 20(21)-en-20-ol ether III was oxidized with N-methylmorpholine N-oxide monohydrate and osmium tetroxide to give the hydroxy ketone IV which was converted into the bromo derivative VIII via the mesylate VI. Hantzsch reaction of the bromo ketone VIII with ethyl thioxamate afforded the thiazole XI whose hemisuccinate XIII and glycoside XV were prepared.

Glucosylation of 5-androsten-3β-ol derivatives containing butenolide, furan or unsaturated ester moieties in the side chain

3-O-(Tetra-O-acetyl-β-D-glucopyranosyl) derivatives II, V, XV and XX were prepared from 5-androstene-3β,17β-diol 17-benzoate (I), (20R)-3β-hydroxy-21-nor-5,22-choladien-(24 -20)-olide (IV), 17β-(2-furyl)-5-androsten-3β-ol (XIV) and methyl (20E)-3β-hydroxy-5,20-pregnadiene-21-carboxylate (XIX), respectively, using tetra-O-acetyl-α-D-glucopyranosyl bromide and silver silicate. The furyl derivative XIV was obtained from methyl 3β-methoxymethyletienate VIII by reaction sequence in which the key reactions were alkylation of the keto sulfoxide IX with bromoacetate, cyclization of the obtained product with sodium borohydride and reduction of the mixture of lactones XI and XII with diisobutylaluminium hydride. The unsaturated ester XIX was prepared from 3β-acetoxy-5-androstene-17β-carbaldehyde (XVII) by treatment with diethyl methoxycarbonylmethylphosphonate and deacetylation of the formed acetyl derivative XVIII. Deacetylation of the acetyl derivatives II, XV and XX afforded the glucosides III,XVI and XXI, respectively; the deacetylation of V was accompanied by opening of the lactone ring under formation of the methyl 21-nor-20-oxo-5-cholen-24-oate derivative VI.

Alternative syntheses of steroidal maleimides

The described synthesis starts from the α-keto esters VIII and XVI which afford the maleimides X and XVIII via products of condensation with carbamoylmethylenetriphenylphosphorane (IX and XVII). In this way, the steroidal maleimides X and XVIII (structurally similar to the cardenolides), derived from 17β-androstanyl-(2-maleimide) and 21-nor-pregnanyl-(2-maleimide) were prepared. Other routes for their preparation have been studied.

Preparation of 2-amino-2,4-dideoxy-D-lyxo-hexopyranose (4-deoxy-D-mannosamine) from 1,6-anhydro-β-D-glucopyranose

1,6-Anhydro-4-deoxy-2-O-p-toluenesulfonyl-β-D-xylo-hexopyranose (III), obtainable by a four-step synthesis from 1,6-anhydro-β-D-glucopyranose, was converted to 3-O-(N-benzylcarbamoyl) derivative V on reaction with benzyl isocyanate. The cyclization of V with sodium hydride in dimethylformamide gave a derivative of oxazolidin-2-one, VII, which on alkaline hydrolysis and hydrogenolysis gave the hydrochloride of 2-amino-1,6-anhydro-2,4-dideoxy-β-D-lyxo-hexopyranose (XI). When 1,6-anhydro derivative XI was treated with hydrochloric acid the hydrochloride of 2-amino-2,4-dideoxy-D-lyxo-hexopyranose (XIV) was obtained. Corresponding N-acetyl derivative XVI is suitable for studies of enzymatic synthesis of N-acetylneuraminic acid.

Synthesis of 17β-steroidal 4-(2-butenolides)

Derivatives of 5-androsten-3β-ol with 2-butenolide ring in position 17β were prepared by addition of lithium salt of protected propargyl alcohol to 17β-carbaldehyde IV, hydrogenation of the formed isomeric acetylenes over P-2 nickel and oxidative cyclization of the obtained olefinic 20,24-diols IX and X. Stereochemistry of the desired lactones XII and XIII was determined by CD spectroscopy. The 17β-(2-furyl) derivative XI was formed as the cyclization side-product. The 3β-hydroxyl was protected by a methoxymethyl group which allowed a selective removal of tetrahydropyranyl group during the synthesis.

Preparation of 2-amino-1,6-anhydro-2-deoxy-β-D-mannopyranose by intramolecular substitution of the tosyloxy group in sterically hindered position of 1,6-anhydro-2-O-p-tolylsulfonyl-β-D-glucopyranose

1,6 : 3,4-Dianhydro-2-O-p-tolylsulfonyl-β-D-galactopyranose (I) was converted to 1,6-anhydro-4-O-benzyl-2-O-p-tolylsulfonyl-β-D-glucopyranose (II) and then reacted with benzylisocyanate to give 3-O-(N-benzylcarbamoyl) derivative III. The cyclization of this substance under the effect of potassium tert-butoxide in tert-butanol gave 3-benzyl-(1,6-anhydro-4-O-benzyl-2,3-dideoxy-β-D-mannopyrano) [2,3-d]oxazolidin-2-one (IV) which was hydrolysed to 1,6-anhydro-4-O-benzyl-2-benzylamino-2-deoxy-β-D-mannopyranose (VIII). Catalytic debenzylation of VIII on palladium on charcoal in the presence of hydrochloric acid gave the hydrochloride of 2-amino-1,6-anhydro-2-deoxy-β-D-mannopyranose (IX), which was acetylated to triacetate XI. Depending on the conditions during catalytic debenzylation of the oxazolidine derivative IV either O-debenzylated derivative VI alone was obtained, or the completely debenzylated oxazolidine derivative VII.