Synthesis and structure-activity relations of disodium cromoglycate and some related compounds

Abstract

OH 0.45 0.77 c NH, -0.48 -0.83 3-[5-(4-Acetamidophenyl)-2-tetrazolyl]propionic Acid (14). A solution of 5 g (0.022 mole) of 3-[5-(4-aminophenyl)-2-tetrazolyl]propionic acid 34 in 200 ml of Ac,0 was allowed to stand for 24 hr at room temperature. The reaction was diluted with 2 1. of water and the solid collected and dried. Recrystallization from MeOH gave 2.4 g (40%) of fine white needles, mp 218°.3-[5-(4-Phenylazophenyl)-2-tetrazolyl]propionic Acid (16). A solution of 10 g (0.043 mole) of 3-[5-(4-aminophenyl)-2-tetrazolyl> propionic acid (34) and 4.6 g (0.043 mole) of nitrosobenzene in 150 ml of warm glacial acetic acid was allowed to stand for 24 hr. The precipitate was collected, washed with MeOH, and recrystallized from THF-MeOH to give 9 g (65%) of red crystals, mp 234°.

The synthesis of angular heteroarenochromones based on 7-hydroxy-8-carbonylchromones

“…They have been proposed as liquid crystals [62] and antiallergic agents [63,64]. They were active in treating extrinsic allergic asthma, intrinsic asthma, hay fever, urticaria and auto-immune diseases [65] and were patented as antihistaminic [66] and аntiasthmatic agents [67][68][69]. A series of articles [80][81][82][83] …”

Synthetic strategies in the construction of chromones

“…In 1977, Lee and coworkers [22] took PPA as a catalyst in the chromone ring closure; in their synthetic route (Scheme ), they firstly applied a two‐step reduction procedure to the chalcone 8 with subsequent demethylation provided the aralkylphenol 9 , which, by modification [23] of the process described by Ruhemann and Stapleton [24] for the formation of chromone‐2‐carboxylic acids from phenols, was converted to the chromone 11 through PPA as the catalyst in the last step. This method was more suitable in the phenolic hydroxyl side chain in a carboxylic acid of the cyclization.…”

Synthesis and Characterisation of Some 2-[2(1-Phenyl-3-Thiophen-2-Yl-1h-Pyrazol-4-Yl)]-Vinyl Chromene-4-Ones

“…The resurgent interest in the chemistry of chromones is, however, due largely to their pharmaceutical activity 4 . The success of disodium chromoglycate in the treatment of certain types of bronchial asthma 5 and recognition of the -0-C=C-(C0)-grouping as the structural requirement for activity in this compound 6 have led to a soate of investigations into chromones bearing a reactive functionality on the pyran ring 7 " 1 .…”