Preparation of 2,3,5-Tri-O-benzyl-4-thio-L-arabino-furanosides and the Corresponding 4′-Thionucleoside Analogues

Wirsching, Jörn; Voß, Jürgen

doi:10.1002/(sici)1099-0690(199903)1999:3<691::aid-ejoc691>3.0.co;2-j

Cited by 26 publications

(3 citation statements)

References 24 publications

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“…Crude 22 (1.73 mmol) was dissolved in acetic anhydride (15 mL), and the mixture was stirred at 100 °C for 3 h. The reaction mixture was concentrated in vacuo, and column chromatography (pentane/EtOAc, 90:10 to 80:20) yielded the title compound (0.88 mmol, 0.42 g, 51% over two steps): 1 H NMR (400 MHz, CDCl 3 ) δ 7.41–7.23 (m, 15H), 6.11 (d, J = 4.0 Hz, 1H), 6.02 (d, J = 3.0 Hz, 1H), 4.86–4.50 (m, 6H), 4.30 (dd, J = 5.2, 3.1 Hz, 1H), 4.27–4.12 (m, 2H), 4.07 (dd, J = 6.5, 5.2 Hz, 1H), 3.81 (q, J = 6.4 Hz, 1H), 3.77–3.68 (m, 2H), 3.59–3.39 (m, 3H); 13 C{ 1 H} NMR (101 MHz, CDCl 3 ) δ 138.4, 138.0, 137.6, 128.6, 128.6, 128.5, 128.5, 128.1, 128.1, 128.0, 128.0, 127.9, 127.9, 127.8, 127.8, 88.9, 86.1, 84.7, 83.9, 82.1, 74.8, 73.6, 73.3, 73.3, 73.2, 72.9, 72.8, 72.7, 71.0, 49.5, 45.4, 21.5, 21.3; IR (neat) 3088, 3063, 3031, 2926, 2863, 1793, 1496, 1453, 1367, 1226, 1098, 1074, 1017, 734, 695 cm –1 ; HRMS (ESI) m / z [M + Na] + calcd for C 28 H 30 O 5 SNa 501.1706, found 501.1713; R f = 0.25 (EtOAc/pentane, 10:90). Spectroscopic data was in agreement with literature …”

Section: Methodssupporting

confidence: 89%

Synthesis, Reactivity, and Stereoselectivity of 4-Thiofuranosides

et al. 2019

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Thiosugars, sugars that have their endocyclic oxygen substituted for a sulfur atom, have been used as stable bioisosteres of naturally occurring glycans because the thiosugar glycosydic linkage is supposed to be stabilized toward chemical and enzymatic hydrolysis. We have performed an in-depth investigation into the stability and reactivity of furanosyl thiacarbenium ions, by assessing all four diastereoisomeric thiofuranosides experimentally and computationally. We show that all furanosyl thiacarbenium ions react in a 1,2-cis-selective manner with triethylsilane, reminiscent of their oxo counterparts. The computed conformational space occupied by the thiacarbenium ions is strikingly similar to that of the corresponding furanosyl oxycarbenium ions, indicating that the stereoelectronic substituent effects governing the stability of furanosyl oxocarbenium ions and thiacarbenium ions are very similar. While the thio-ribo-furanose appears to be less reactive than its oxo counterpart, the thio-ara-, lyxo-, and xylo-furanosides appear to be more reactive than their oxygen equivalents. These differences are accounted for using the conformational preference of the donors and the carbocation intermediates. The lower reactivity of the thio-ribo furanosides in (Lewis) acid-mediated reactions and the similarity of the thia- and oxocarbenium ions make thio-ribo-furanosides excellent stabilized analogues of the naturally occurring ribo-furanose sugars.

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Section: Methodssupporting

confidence: 89%

Synthesis, Reactivity, and Stereoselectivity of 4-Thiofuranosides

et al. 2019

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“…Οι Wirshing και Voss το 1999 χρησιμοποίησαν τη D-ξυλόζη ως πρώτη ύλη, για να συνθέσουν ένα ακετυλογλυκοζίτη με τη χαρακτηριστική δομή της αραβινόζης, και στη συνέχεια με την αντίδραση Vorbrüggen συνέδεσαν τη θυμίνη και την ουρακίλη (Σχήμα 2-21). 102 Συνθήκες και αντιδραστήρια: (i) T(TMS)2, TMSOTf, MS, ACN, -18 o C, 2h, 78% (α/β:2/1). Σχήμα 2-21.…”

Section: παλιοτερες συνθεσεις θειονουκλεοζιτωνunclassified

Σύνθεση Θειοσακχάρων Και Θειονουκλεοζιτών

Κωτούλας¹

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Η παρούσα διδακτορική διατριβή αφορά στην ανάπτυξη μιας συνθετικής μεθοδολογίας των απιοθειονουκλεοζιτών της θυμίνης, της ουρακίλης και της κυτοσίνης, καθώς και των 3’C-δεοξυπαραγώγων τους. Στη σύνθεση χρησιμοποιείται ως πρώτη ύλη η αραβινόζη και με χρήση στερεοειδικών αντιδράσεων μετασχηματίζεται σε ένα κατάλληλα υποκατεστημένο σουλφοξείδιο, το οποίο με εφαρμογή συνθηκών αντίδρασης Pummerer οδηγεί στο σχηματισμό του επιθυμητού απιοθειονουκλεοζίτη. Έτσι, χρησιμοποιώντας την L- αραβινόζη προκύπτει ο αντίστοιχος D-απιοθειονουκλεοζίτης και ανάλογα από τη D-αραβινόζη το L-παράγωγο.Μελετήθηκε η στερεοεκλεκτικότητα της αντίδρασης Pummerer, είτε στην κλασσική εκδοχή της με τον οξικό ανυδρίτη είτε με τις πυριμιδίνες και προσπάθεια ελέγχου της αναλογίας των προκυπτόντων προϊόντων, ανάλογα με την ομάδα προστασίας που φέρει το υδροξύλιο της πλευρικής αλυσίδας (είδος και όγκος ομάδας). Για την πληρέστερη κατανόηση του τρόπου δράσης των χρησιμοποιούμενων σουλφοξειδίων, έγινε προσπάθεια πλήρους χαρακτηρισμού της δομής τους.Οι δεοξυ-απιοθειονουκλεοζίτες μελετήθηκαν ως προς την αντικαρκινική τους δράση σε πέντε σειρές καρκινικών κυττάρων και σε ορισμένες περιπτώσεις βρέθηκαν ενεργοί με τιμές IC50 < 10μM.

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“…Formation of the open-chain dithioacetals from dehydrative glycosylation was a major hurdle and it has been reported in literature. Imbatch's 35 and Voss's 36 research groups reported the synthesis of 4-thio-D-ribofuranose and 4-thio-Dxylofuranose using hydrochloric acid as Brønsted acid and gave dithioacetals as major product in good yields (Figure 1.13). Additionally, Montgomery's research group 37 described the synthesis of 4thio-D-ribofuranose by using SnCl 4 as Lewis acid afforded dithioacetal product in good yield.…”

Section: Dithioacetal Formation From Glycosylationmentioning

confidence: 99%

Synthesis of thiofuranosides by dehydrative glycosylation in micellar media

Ratthachag

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Green and aqueous-based dehydrative glycosylation of thiofuranosides in micellar media was developed. The thiofuranosides are useful as precursors for carbohydrate synthesis, biological active molecules, and bio-surfactants. Dodecylbenzenesulfonic acid (DBSA), a commercially available Br?nsted acid-surfactant, was employed to increase solubility of substrates and enhance rate of the glycosylation. Herein, we report the dehydrative glycosylation of furanosides and pyranosides with aliphatic, aromatic, and heterocyclic thiols in aqueous media to afford the thiofuranosides. Microwave irradiation led to improved yields and shorter reaction times. Other reaction parameters such as temperature and the amount of acid used were also optimized. Aliphatic and aromatic thiofuranosides were prepared from lactol precursors in moderate yields (24?72%) when using 100 mol% DBSA. Noteworthy, the open-chain dithioacetal which is a common by-product from the dehydrative glycosylation was not detected under these reaction conditions. Moreover, the methodology was simple and convenient to set up without the requirement for anhydrous conditions.

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Preparation of 2,3,5-Tri-O-benzyl-4-thio-L-arabino-furanosides and the Corresponding 4′-Thionucleoside Analogues

Cited by 26 publications

References 24 publications

Synthesis, Reactivity, and Stereoselectivity of 4-Thiofuranosides

Synthesis, Reactivity, and Stereoselectivity of 4-Thiofuranosides

Σύνθεση Θειοσακχάρων Και Θειονουκλεοζιτών

Synthesis of thiofuranosides by dehydrative glycosylation in micellar media

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