Paul-Louis Compagnon

Cetones pyridiniques : VIII. Metallation regioselective de la s-collidine: Effets de metaux et de solvants☆

Abstract The regioselective metalation of s-collidine yielding two anions, trapped by PhCN, was found to be essentially determined by the solvent and the size of the cation: twelve solvents and three cations (Li+, Na+, K+) were examined. The effect of various bases (alkali metals, phenyllithium, amides, “complex bases”, amines) and of some metallic cations (Li+, Ag+, Pd2+) was studied. The solvent basicity was not responsible for the regioselectivity.

Synthesis, antifungal activity and structure-activity relationships of 2-(alkyl or aryl)-2-(alkyl or polyazol-1-ylmethyl)-4-(polyazol-1-ylmethyl)-1,3-dioxolanes

Summary A series of 2-(alkyl or aryl)-2-(alkyl or polyazol-1-ylmethyl)-4-(polyazol-1-ylmethyl)-1,3-dioxolanes Ia-u was synthesized and tested in vitro against pathogenic fungi in man, animals and plants: Candida albicans, Aspergillus flavus and Fusarium solani . Compounds Iq-t with two polyazol groups have an in vitro activity against these fungi with MIC (minimum inhibitory concentration) value of 5 μg mL −1 .

Electrosynthesis of (fluorenone)tricarbonylchromium

Abstract (Fluorenone)tricarbonylchromium has been prepared in up to 46% yield from (fluorene)tricarbonylchromium by two electrochemical methods whose key step is the formation of the (fluorenyl)tricarbonylchromium anion which reacts further with oxygen. The first method takes advantage of the basic properties of the superoxide anion, generated electrochemically in aprotic media; this anion is able to abstract a proton from (fluorene)tricarbonylchromium. In the second method, (fluorene)tricarbonylchromium is reduced to its anion in an inert atmosphere, prior to the introduction of oxygen.

Electroreduction of (benzophenone)tricarbonylchromium and (fluorenone)tricarbonylchromium in the presence of electrophiles

Abstract (Benzophenone)Cr(CO)3 (2) and (fluorenone)Cr(CO)3 (3) are reduced at a mercury pool cathode in aprotic media, in the presence of an electrophile which is more difficult to reduce. The results are compared with those which are obtained with the corresponding parent ketone. In the presence of 1,3-dibromopropane, a complexed olefinic alcohol 7a is the major isolated compound when 2 is the substrate, whereas a complexed spiro ether 8b is obtained with 3 as substrate. The electroreduction of 3 in acetonitrile in the presence of an equivalent amount of 4-chlorobutyryl chloride gives mainly the diacylated complex 10a. The unexpected formation of a nitrile complex 12a is also observed, which indicates an interaction between an intermediate species and acetonitrile. Complex 12a is obtained in low yield by the electroreduction of 3 in the presence of 3-bromopropionitrile. Under these conditions the major compound is (fluorenol)Cr(CO)3.

New polyazole derivatives from 2-(2,4-dichlorophenyl)-1,3-dioxolane. Antifungal activity. Structure-activity relationships

Six new polyazole derivatives from 2-(2,4-dichlorophenyl)-1,3-dioxolane were studied for their antifungal activity against pathogenic fungi for humans and animals. The antimycotic effect was largely restricted to the filamentous fungi with Aspergillus fumigatus and Scedosporium apiospermum being remarkably susceptible. Three compounds were as effective as the two references, ketoconazole and oxiconazole. The structure-activity relationships revealed that an ‘oxime group’ combined with four chlorine atoms increased the antifungal properties of the chemical series.

Electrochemical synthesis of N-phenyltetrahydro-oxazinone—role of the solvent

Abstract The electrochemical synthesis of 2-phenyltetrahydro-2H-1,2-oxazin-3-one 1 is performed by electroreduction in aprotic solvent of nitrosobenzene in the presence of an equivalent of 4-chlorobutyryl chloride 2b . In DMF, the yield does not exceed 8% at 18°. In MeCN, it reaches 35% at 18° and 42% at −18°. It is suggested that the lower yield obtained in DMF is due mainly to a higher reactivity of the dielectrophile which forms an immonium salt in this solvent. It is shown that the chemical reduction of nitrosobenzene (HMPT, Na) followed by the addition of 2b , does not lead to 1 .

One-step electrosynthesis of tetrahydrofuran and tetrahydropyran derivatives

Abstract The one-step electrosynthesis of tetrahydrofuran and tetrahydropyran derivatives was achieved by electrogenerating in N,N -dimethylformamide and at a mercury pool cathode, radical-anions of benzophenone or fluorenone in the presence of an equivalent of 1,3-dibromopropane 1 or 1,4-dibromobutane 2 . In all electrolyses, a competition between ring alkylations and O- and C-alkylations of the keto group is observed. In the case of fluorenone, the spiroethers were isolated as the main compounds. Their yields after purification were respectively 41 and 50% in the presence of 1 and 2 . For benzophenone, the yields of the cyclic ethers were low, due mainly to the competitive formation of bridged compounds; the yields of tetrahydrofuran and tetrahydropyran derivatives were respectively 10 and 23%.

Formation of fluoren-9-ylidenesuccinonitrile by addition of electrogenerated –CH2CN anions to fluoren-9-one and flouren-9-ylideneacetonitrile

When –CH2CN anions are electrogenerated in acetonitrile addition occurs to fluoren-9-one (FICO) or fluoren-9-ylideneacetonitrile (FICCHCN) to give the condensation of fluorenone and succinonitrile have failed.

Molecules ethyleniques et acetyleniques conjuguees VI. En evidence de la formation intermediaire d'allenol-1 au cours de la reduction polarographique en milieu acide, de cetones α-acetyleniques α′-pyridiniques

During the polarographic reduction, in acid medium, of α- and γ-pyridylphenylpropynones 2α and 2γ, the intermediate formation of unstable allenols-1 was shown. These compounds are fast isomerised into ethylenic ketones. In the case of 2α, the isomerisation rate is 0.167 s−1 at 21°C (HCl 0.6 N; EtOH 30%); it is 48 times faster than the isomerisation rate into saturated ketone of the corresponding enol. The stability of such allenol-1 compounds is due to the vicinity of the pyridinium ion.