Photochemical reduction and decarboxylation of 2-phenylquinoline-4-carboxylic acids

Abstract

NotesFrom a synthetic point of view methanolysis of 1 (and likely similar unimolecular solvolyses) appears to be of limited usefulness. Solvolysis of 1 and 2 in aprotic solvents in the presence of strong nucleophiles should conversely represent a good alternative to the displacement of analogous 21-chloro derivatives lg2 and 2c5 for the introduction of substituents at C-21. Experimental Section617a-Pregna-5,20-dien-3/S,17-diol 3-Acetate 17-Trifluoroacetate (1). A solution of 17a-pregna-5,20-dien-3/3,17-diol 3-acetate (la)2 (0.36 g, 1 mmol) in pyridine (1.7 mL) was treated with trifluoroacetic anhydride (0.7 mL) at 0 °C for 15 min. Then cold 1 N HC1 (11.7 mL) was added and the mixture was extracted with ether. The ether layers were washed to neutrality with cold water, dried (Na2S04), and evaporated. The residue (0.45 g) was crystallized from n-hexane (0.33

Comet Halley as an aggregate of interstellar dust and further evidence for the photochemical formation of organics in the interstellar medium

“…On the other hand the excess CO observed in comet Halley, relative to H20, as compared with the interstellar dust ratio, is observed as a distributed species and is therefore a decomposition product of species more refractory than H20 (Eberhardt et al, 1987). The organic residues created in the laboratory have been subjected to two forms of analysis: GC/MS and electron impact mass spectroscopy (Mendoza-Gdmez et al, 1992).…”

Synthetic Organic Photochemistry

“…In this case, electron transfer from the carboxylate to pyridinium is an intramolecular process giving rise to diradicals related to 483. The photochemical decarboxylation of 2-arylquinoline-4-carboxylic acids 484 observed byEpling and Yoon,(365) which form the corresponding quinolines 485 in excellent yields, appear to follow similar routes.…”

Photoreactivity of Phototoxic Antimalarial Compounds

“…Compounds 2a and M were prepared by thermal decarboxylation of the corresponding cincophens as previously described (Epling er al., 1978). Alcohol 3a, mp 188-189", was prepared from the corresponding cincophen by esterification in methanol, followed by reduction with sodium borohydride in methanol at reflux for 24 h. Alcohol M, mp 203-205", was obtained similarly by lithium aluminum hydride reduction of the cincophen methyl ester in ether (Epling et al, 1978).…”