Glucopyranosyl isothiocyanate preparation

Isomerization of organic thiocyanates to isothiocyanates is also discussed in other articles.25 29 The first sugar isothiocyanate reported, namely, 2,3,4,6-tetra-O-acetyl-/3- D-glucopyranosyl isothiocyanate (2) was synthesized by Emil Fischer7 in 1914 by treatment of 2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl bromide (1) with silver thiocyanate in anhydrous xylene. It was also prepared by Muller and Wilhelms8 by thermal isomerization of the corresponding thiocyanate 3, obtained by treatment of 1 with potassium... 

Some new 5-(benzylamino)thiatriazoles have been prepared by standard methods.12 5-(Tetra-0-acetyl-/T-D-glucopyranosylamino)-thia-triazole was prepared by the action of HN02 on 4-(tetra-0-acetyl-/3-D-glucopyranosyl)thiosemicarbazide as well as from hydrogen azide and tetra-0-acetyl-/J-D glucopyranosyl isothiocyanate.62 Substituted 5-aminothiatriazoles may be obtained from C-sulfonylthioformamides on reaction with azide ion.63... 

Jochims [134] and Hassan s [135] groups reported the efficient use of l-aza-2-azoniaallene salts 119 and 0-acetylated j6-D-glucopyranosyl isothiocyanate 89 for the preparation of glucopyranosylimino-l,3,4-thiadiazoles 121 and 122. These salts, prepared from chloroalkylazo derivatives 118 and antimony (V) chloride, can undergo 1,3-dipolar cycloadditions with multiple bonds-containing compounds, such as alkynes, alkenes, isocyanates, isothio-... 

The synthesis of dithioxopyrimidine nucleosides 138 from acetylated /0-D-glucopyranosyl isothiocyanate 89 has been reported by Fuentes and co-workers [149]. J -Glucosylthioamides 137, prepared by reaction of 89 with N-aryl-enaminoesters or enaminones 136 in basic medium, were transformed into glucosyl dithioxopyrimidines nucleosides 138 by treatment with thiophosgene (Scheme 30). The concomitant glycosylamides formation... 

Sample preparation Prepare metyrosine methyl esters by treatment of racemic metyrosine with absolute MeOH and concentrated sulftiric acid (JAm.Chem.Soc. 1978,100, 6536). Dissolve 5 mg of the racemic metyrosine methyl esters in 5 mL MeCN water 50 50 containing 0.5% v/v triethylamine. Heat a 50 p.L quot of this solution at 45° for 15 min, add 10 fiL 0.5% w/v 2,3,4,6-tetra-0-acetyl-/S-D-glucopyranosyl isothiocyanate in MeCN, heat at 45° for 2 h, add 10 xL 0.5% v/v hydrazine in MeCN (Caution Hydrazine is carcinogenic and toxic ), heat at 45° for 15 min. Evaporate the mixture under a stream of nitrogen, reconstitute the residue with 250 p,L mobile phase, inject a 100 fiL aliquot. (Prepare 2,3,4,6-tetra-0-acetyl-/S-D-glucop5rranosyl isothiocyanate solution and hydrazine solution fresh each day.)... 

Emil Fischer, as part of a study of a series of S- and iV-glucosides, prepared 1-D-glucosylurea and 1-D-glucosylthiourea from the corresponding isocyanate (IV) and isothiocyanate (V), respectively. These intermediates were obtained by the condensation of tetra-O-acetyl-a-D-glucopyranosyl bromide (III) with silver cyanate or thiocyanate in anhydrous xylene. The... 

The glycosyl ureide and thioureide obtained through the isocyanate and isothiocyanate routes were prepared from tetra-O-acetyl-a-D-glucopyranosyl bromide. The glycosyl ureides derived from this source are identical with those prepared by the acid-catalyzed condensation of D-glu-cose with urea and with thiourea. 

The same group prepared N-(/S-D-glucopyranosyl)oxazolidine-2,4-diones [146] and N-(/l-D-glucopyranosyl)imidazolidine-2,4-diones [147] by desulfurization-condensation of glucosyl isothiocyanate with a-hydroxyacids and J -substituted a-aminoacids, respectively, in the presence of silver triflu-oroacetate and triethylamine. 4-Glucosyl-l,2,4-oxadiazolidine-5-thiones were also prepared by reaction of protected glucosyl isothiocyanates with an ox-aziridine ring [148]. 

---