ABSTRACT
The antibacterial properties of water-soluble gold(I) complexes [1-methyl-3-(3-sulfonatopropyl)imidazol-2-ylidene]gold(I) chloride (C1), [1-mesityl-3-(3-sulfonatopropyl)imidazol-2-ylidene]gold(I) chloride (C2), [1-(2,6-diisopropylphenyl)-3-(3-sulfonatopropyl)imidazol-2-ylidene]gold(I) chloride (C3) and [1,3-bis(2,6-diisopropyl-4-sodiumsulfonatophenyl)imidazol-2-ylidene]gold(I) chloride (C4) and the respective ligands were assessed by agar diffusion and broth macrodilution methods against Gram-positives Staphylococcus aureus, Enterococcus faecalis and Micrococcus luteus and the Gram-negative bacteria Yersinia ruckeri, Pseudomonas aeruginosa and Escherichia coli. Viability after treatments was determined by direct plate count. The bactericidal activity displayed by C1 and C3 was comparable to that of AgNO3.
Subject(s)
Anti-Bacterial Agents/pharmacology , Coordination Complexes/pharmacology , Gold/chemistry , Heterocyclic Compounds/pharmacology , Anti-Bacterial Agents/chemistry , Coordination Complexes/chemistry , Enterococcus faecalis/drug effects , Escherichia coli/drug effects , Heterocyclic Compounds/chemistry , Methane/analogs & derivatives , Methane/chemistry , Microbial Sensitivity Tests , Micrococcus luteus/drug effects , Pseudomonas aeruginosa/drug effects , Solubility , Staphylococcus aureus/drug effects , Yersinia ruckeri/drug effectsABSTRACT
The solvent-free indium-promoted reaction of alkanoyl chlorides with sterically and electronically diverse arylstannanes is a simple and direct method for the regioselective synthesis of primary, secondary and tertiary alkyl aryl ketones in good to excellent isolated yields (42-84%) under mild and neutral conditions. The protocol is also adequate for the synthesis of aryl vinyl ketones. Reaction times are drastically reduced (from 3-32h to 10-70min) under ultrasonic irradiation. Evidences for the involvement of a homolytic aromatic ipso-substitution mechanism, in which indium metal acts as radical initiator, are presented. It is possible the transference of two aryl groups from tin, thus improving effective mass yield, working with diarylstannanes as starting substrates.
Subject(s)
Indium/chemistry , Ketones/chemical synthesis , Sonication , Tin Compounds/chemistry , Catalysis , Hydrocarbons, Chlorinated/chemistry , Ketones/chemistry , Ketones/radiation effects , Molecular Structure , Sound , Tin Compounds/radiation effectsABSTRACT
We describe herein an efficient method for the synthesis of unsymmetrically-substituted biphenyls using a sonochemical variation of the Stille coupling, whose results have also been compared with the conventional silent reaction. Ultrasound significantly enhances this useful organometallic transformation affording products in higher yields and in shorter reaction times than non-irradiated reactions. The scope has been explored with a selection of arylstannanes as precursors and, remarkably, no by-products resulting from homo-coupling could be detected.
Subject(s)
Sonication/methods , Tin Compounds/chemistry , Tin Compounds/radiation effects , High-Energy Shock Waves , Radiation DosageABSTRACT
Bulky arylstannanes and bulky aroyl chlorides are good reaction partners for the synthesis of two-, three-, and even four-ortho-substituted benzophenones, in good to excellent isolated yields (47-91%). Three simple and direct routes, with differential advantages, are proposed: (i) a catalyst-free protocol, in o-dichlorobenzene (ODCB) at 180 °C; (ii) a room temperature protocol, using AlCl(3) (0.5 equiv), in dichloromethane (DCM); and (iii) a solvent-free, indium-promoted procedure. A radical mechanism is proposed for the indium-mediated reactions.
Subject(s)
Ketones/chemistry , Ketones/chemical synthesis , Tin Compounds/chemistry , Catalysis , Chlorobenzenes/chemistry , Indicators and Reagents/chemistry , Indium/chemistry , Substrate SpecificityABSTRACT
The exceptional leaving group ability of the trimethylstannyl group in electrophilic aromatic substitutions makes possible the synthesis, in a single step, of bi- and triaroylarenes through the catalyst-free, regioselective reaction of bi- and tristannylarenes with different aroyl halides in o-dichlorobenzene as solvent. Specific di- and triketones are obtained in good to excellent yields (45-83%).
Subject(s)
Polycyclic Aromatic Hydrocarbons/chemistry , Catalysis , Halogens/chemistry , Tin Compounds/chemistryABSTRACT
Ketones are converted into vinyl diethyl phosphate esters (VinDEP), which under photostimulation reacted with sodium trimethylstannide (1) or sodium triphenylstannide (2) in liquid ammonia affording vinylstannanes via a vinylic S(RN)1 mechanism. Thus, (1-phenylvinyl)DEP (3), (3,4-dihydro-1-naphthyl)DEP (7), (3,4-dihydro-2-naphthyl)DEP (9), (E)-(1,2-diphenylvinyl)DEP (12), (E/Z)-(1-methyl-2-phenylvinyl)DEP (14) and (E)-(1-phenyl-2-methylvinyl)DEP (16) react with 1 and 2, under photostimulation, leading to the corresponding substitution products in good to excellent yields (45-89%). On the other hand, there is no reaction between (1-cyclohexenyl)DEP (5) or (1-benzylvinyl)DEP (18) with either 1 or 2, under similar conditions. These reactions appear to be strongly dependent on structural features of the vinyl phosphate since only conjugated vinyl phosphates afforded substitution products. These substitution reactions are completely regioselective and stereoconvergent. It seems to be the first example of a vinylic S(RN)1 process involving organotin anions as nucleophiles.
