The former reaction in the presence of excess triethylamine resulted in the hydroxy derivative (377; R2 = OH) 〈90EUP404525〉. We use cookies to help provide and enhance our service and tailor content and ads. Acetic anhydride can be used as a dehydrating agent for the formation of anhydrides (Scheme 2).This may be achieved in the absence of catalysts or with acidic or basic catalysts < 09CB3484, 25CB1418, 57JA3508, 85LA1935 >. You can actually make ethanoic anhydride by dehydrating ethanoic acid, but it is normally made in a more efficient, round-about way Copyright © 2002 Published by Elsevier Ltd. https://doi.org/10.1016/S0040-4020(02)00116-3. Thus (320) with ethanolic ammonia readily furnished 9-methyladenine (Scheme 124) 〈59JCS4040〉. It introduces their chemical reactivity in a general way. Similarly (316) and methoxyamine furnished 9-(2,3-O-isopropylidene-β-d-ribofuranosyl)-6-methoxyaminopurine (319). The reaction has been extended to include a glucopyranosylimidazole which produced 9-glucopyranosyladenine 〈75CC964〉. Acetic anhydride adds to the 3,4-C–N double bond of 2,3-benzodiazepines forming the N-tosylate derivative which undergoes deacylation with sodium borohydride <2000MI309>. The main difference is the presence of an electronegative substituent that can act as a leaving group during nucleophile substitution reactions. The oxidation of the secondary alcohol is followed by elimination of benzoic acid, producing an enone. Acid anhydride also used in the preparation of anhydrides like reaction with nitric acid make acetyl nitrate. RICHARD S. MONSON, in Advanced Organic Synthesis, 1971. The reaction mixture is mixed with water or ice.d This may result in the precipitation of the product that can be separated by filtration. C(2)-Labelled adenine has been prepared by this method using labelled formic acid 〈53JA5753〉.
Similar methods have been used to prepare nucleosides including inosine 〈62JCS2937〉 which results from the 1-β-d-ribofuranosylimidazole (304; Scheme 114) and in a similar manner, 7-β-d-ribofuranosylhypoxanthine (306) was obtained from the isomeric aminoimidazole nucleoside (307; Scheme 115) 〈59JCS2893〉.
The reaction mixture was filtered and evaporated to dryness.
0000004841 00000 n By continuing you agree to the use of cookies. Two years later,56 they presented a full paper, in which optimized conditions for this oxidation were established using yohimbine (16) as a model substrate. $\begingroup$ The aldehyde is the only carbonyl group that can enolise, the ester groups cannot because of the quaternary carbon between them. This problem is reduced by addition of sodium acetate to the reaction medium67 or by using trifiuoroacetic anhydride.68,69 With this more reactive activating agent, high yield conversion of sulfoxides to α-trifluoroacetoxy sulfides is achieved under much milder conditions (0–20 °C).