Acid bromides synthesis

Some useful resins that have found their way into quite substantial applications are the carbonate resins. For instance, trimethylammonium bicarbonate resin (8) is used to neutralize carboxylic acids or strong mineral acids formed in situ in specific reactions. An interesting example is the quenching/scavenging of acid bromide reported by Staufer and Kat-zenellenbogen74 during the synthesis of tetra-substituted pyrazoles (40) from immobilized starting materials as seen in Fig. 18. 

Borgman, R. J., Smith, R. V., Keiser, J. E. The acetylation of apo-morphine. An improved method for the selective preparation of diacetylapomorphine utilizing trifluoroacetic acid/acetyl bromide. Synthesis 1975, 249-250. 

A related synthesis produces indolones by a different Friedel-Crafts route. The Stolle synthesis reacts with a secondary aryl amine such as diphenylamine with an a-chloro acid chloride or an a-bromo acid bromide to give an a-bromoamide (such as 315) or an a-chloroamide. An early version of the reaction used oxalyl chloride, but a more typical example is the reaction of 2-bromopropanoyl bromide with 314 to give 315. Friedel-Crafts cyclization (with AICI3) led to the indolone 316.1 ... 

D-Xylosyl-D-glucose (primeverose). M.p. 209°C. [o ]d +23° —> —3.4° (water) obtained by partial hydrolysis of a glycoside from Primula officinalis 132) from madder root 133). (See Ruberythric acid.) The synthesis has been accomplished by coupling 2,3,4-tri-O-acetyl-a-D-xylosyl bromide with 1,2,3,4-tetra-O-acetyl-iS-D-glucose 134). 

Intramolecular nitro-Michael cyclization to 29 is completed in THF at room temperature with 2 mol of cesium fluoride and myristyltrimethylammonium bromide as promoters. Prevailing trans,trans-isomet 29 is separated by crystallization and the nitro derivative reduced to amine 30 in 98 % yield. Treatment with MeONa in MeOH afforded lactame 31, which is reduced by LiAUTi to known pyrrolidine derivative 2. Direct conversion of 2 to P-lycorane by Pictet-Spengler type cyclization using paraformaldehyde and mineral acid failed. Synthesis was accomplished in high yield by a detour, methoxycarbonylation to 32, cyclization to 33 and final LiAllTj-reduction of six-membered lactame to ( )- lycorane TM 9.5. 

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