Benzoyl chloride-Pyridine

Selective dibenzoylation64 of methyl a-L-fucopyranoside (20) with benzoyl chloride-pyridine at a low temperature gave the amorphous 2,3-dibenzoate in high yield (80-85%) methyl 3-O-benzoyl-a-L-fuco-pyranoside was also isolated, in 6% yield. [Similar treatment of methyl 6-deoxy-a-L-mannopyranoside (a-L-rhamnopyranoside) gave the corresponding 2,3-dibenzoate in 50% yield, although, in this compound,... 

Aminoethylcellulose Perchlorate Vol l,p A204 R Cellulose Benzoates ate esters of cellulose benzoic acid. The mono- and di-benzoates were prepd by treating cellulose in alk soln with benzoyl chloride. Tri-benzoate was reported to have been prepd by the action of benzoyl chloride pyridine on cellulose at 110-30° in the presence of nitrobenzene. The prod is sol in chlf nitrobenz(Ref 6)... 

Direct tri-0-alkylation of calix[4]arenes has been reported to lead to the syn/syn isomer using bases such as BaO, BaO/Ba(OH)2 or CaH2 in DMF " . The tribenzoate of the p-unsubstituted calix[4]arene, one of the first examples of selectively derivatized calix[4]arenes, was obtained as the anti-syn isomer (benzoyl chloride/pyridine) , while the tribenzoate of 2a obtained in toluene with iV-methylimidazole as base (70% yield) was described as the syn-syn isomer, assuming a partial cone conformation with an inverted phenol ring . Both tris(3,5-dinitrobenzoates) of 2a were obtained by acylation with 3,5-dinitrobenzoyl chloride/l-methylimidazole. While 95% of the syn-syn isomer was formed in acetonitrile, 70% of the anti-syn isomer was obtained in chloroform . 

Veratramine is readily acylated to 0,0, AT-triacyl derivatives, acetic anhydride yielding the triacetyl compound XXVIII and benzoyl chloride-pyridine the corresponding tribenzoyl derivative. Alkaline hydrolysis... 

Mekonnen and Crank also found the same reaction dichotomy in Friedel-Crafts reactions of 622 (X = O) with acid chlorides or acid anhydrides. In general, acylation of 622 (X = O, R = CH3) with acetic anhydride or benzoyl chloride/ pyridine afforded the corresponding 2-(acylamino)-4-methyloxazole 630a and 630b (Scheme 1.174). However, low-temperature acetylation or aroylation of 622 (X = O, R = CH3) in the presence of two equivalents of AICI3 produced a 5-acyl-2-amino-4-methyloxazole 631 in low to modest yield. The authors reported that AICI3 was the most effective Lewis acid (SnCLj and TiCL) and that the reaction required two equivalents of Lewis acid. Selected examples are shown in Table 1.48. 

Cold acetic anhydride-pyridine has been shown to give the crystalline a-triacetate with 4,6-O-ethylidene-0 -D-glucopyranose whereas previous work has given non-crystalline mixtures of a- and /3-anomers or only /3-anomer with hot acetic anhydride-sodium acetate. However, cold benzoyl chloride-pyridine gave Q ,/3-anomeric mixtures. ... 

The benzoyl chloride-pyridine complex also reacts with hydrogen sulfide at about -20°C to afford an 85% yield of dibenzoyl sulfide (Eq. 5). 

---