STUDIES ON LACTONES RELATED TO THE CARDIAC AGLYCONES. VI. THE ACTION OF DIAZOMETHANE ON CERTAIN DERIVATIVES OF Α-Pyrone

A Carbomethoxylated Polyvalerolactone from Malic Acid: Synthesis and Divergent Chemical Recycling

“…Diels–Alder reactions of 2 or 3 with various dienophiles have been used to prepare biorenewable terephthalic acid and methyl terephthalate derivatives . Hydrogenation reactions of 2 or of 3 are reported, but in no case has the saturated lactone product been fully characterized. A significant, competing hydrogenolysis of the C5–O bond during these reactions leads to the competitive production of products 5a or 5b .…”

Model studies toward the synthesis of the bioactive diterpenoid, harringtonolide

“…Treating 24 with ethereal diazomethane 175 afforded 32 in 82% yield (Scheme 9). 15 When the newly prepared pyrone 32 and indenone 12 were subjected to high pressure, cycloadduct 33 was obtained. Elaboration of 33 posed an interesting challenge.…”

“…, 312 (24), 297 (6), 252 (7), 239 (15), 225 (8), 202 (14), 182 (84), 167 (32), 145 (90), 121 (100), 102 (28), 91 (23), 77 (14). The alcohol 18 (275 mg, 0.8 mmol) and N-iodosuccinimide (225 mg, 1 mmol) were dissolved in THF (25 ml).…”

Reinvestigation of the reaction of coumalyl chloride with ammonia and amines. .alpha.-Aminomethyleneglutaconic anhydride; structure and properties

“…Coumalyl chloride was prepared by the method of Fried and Elderfield. 19 Only freshly prepared samples were used in all experiments. Reaction of coumalyl chloride with ammonium hydroxide was carried out as described by Wiley and Knabeschuh.4 -Aminomethyleneglutaconic anhydride (2a), mp 250-252 °C dec, was purified by recrystallization from a large volume of 50% ethanol.…”

“…The eluent, about 50 mL, was lyophilized to give 160 mg of orange amorphous solid which became dark and resinous upon standing. Attempted crystallization from various organic solvents invariably resulted in dark red resinous material: MS m/e (relative intensity) 140 (71, M+), 112 (100), 95 (19), 94 (38), 84 (76), 68 (24), 66 (24) .…”