Protocols base-free

Alkenylsilanols have been shown to serve as activators themselves in the presence of strong base, opening a route to a highly effective, fluoride-free protocol ((79)276 and (80)277). 

Through the use of arenediazonium salts, the straightforward transformation of amines into cross-coupling products can be realized. Whenever the diazonium salts do not tolerate bases and strong nucleophiles (e.g., phosphines), base- and phosphine-free protocols have to be used. Heterocyclic carbene ligands serve well in cross-coupling of Aryl- and vinylboronic acids, or alkylboronates with arenediazonium salts.369,370 Several convenient phosphine-free protocols have been developed for the same purpose.371-373... 

A ligandless and base-free Gu-catalyzed protocol for the coupling of arylboronic acids and potassium aryltrifluoro-borates with primary and secondary aliphatic amines and anilines was developed. The process utilized catalytic copper(n) acetate monohydrate or CuCl2 and 4 AMS in dichloromethane at slightly elevated temperatures under an atmosphere of oxygen (Equation (232)).1019-1021... 

DNA template preparations are a major source of contamination in cell-free synthesis. In vitro translation reactions are sensitive to contamination by salts, RNases, detergents, and alcohol, all of which are typically used in commercial plasmid purification kits. As such, plasmids prepared by resin-based purification protocols must be further purified by phe-nol/chloroform and chloroform extraction. DNA should be precipitated with isopropanol, washed in ethanol, dried, and taken up in RNase-free water to a concentration of about 1 mg mL . The DNA should be stored frozen, in small aliquots. 

Dimerization of 1-alkynes is accomplished with 1% Pd/C, Cul in DMSO under oxygen at room temperature/ This protocol is base-free and ligand-free. Homocoupling of Grignard reagents also takes place in dry air, with some MnCl2 or FeCly as catalyst. ... 

On the other hand, bases possessing high Lewis basicity might serve as hgands in phosphine-free protocols. For example, tetramethylguanidine (TMG) and 1,4-diazabicyclo [2.2.2]octane (DABCO) were shown to improve yields markedly in phosphine-free reactions of aryl iodides, bromides and activated chlorides, compared with identical system without additive. Representative protocols PdCla (0.1 mol%), TMG, NaOAc, NfT-dimethylacetamide (DMA), 140 °C or Pd(OAc)2 (0.0001-5 mol%), DABCO, K2CO3, dimethylformamide (DMF), 120 °C. 

These catalytic methods all rely on the use of Ugands or a base. A ligand-less, base-free method was subsequently developed to effect high-yielding crosscouplings of anilines and a wide range of aliphatic amines with various aryl boronic acids (Scheme 4.14) [50]. Relative to the myristic acid-based method, this protocol was shown to be superior for aliphatic amines, but inferior in the hans-formation of aniline derivatives. 

A new protocol for the aUcynylation of various aromatic as well as aliphatic aldehydes (48) and alkynes (109) using ZnO under solvent- and base-free conditions was developed by Hosseini-Sarvari and Mardaneh (2011b) (Scheme 9.33). This demonstrates an important strategy for C-C bond formation in organic chemistry. 

Some but not all organic reactions proceed well in the absence of solvent(s). Develop a solvent-free protocol for the aldol reaction using solid sodium or potassium hydroxide as the base. The reaction can be successfully performed on a 5-10 mmol scale, using an equivalent of base. Bear in mind that the base should be finely divided, so it should first be crushed with a mortar and pestle. In addition, the condensation partners should be mixed thoroughly before the base is added. The reaction should take no more than 20-25 minutes, and the mixture should be acidified to pH 5 with 10% HCI prior to isolation of the product. Characterize the product by its melting point and using spectroscopic techniques. 

A base- and ligand-free protocol has been delineated, obtaining only the C2-arylated product in excellent yield (99%) using 2-iodoanisole as a coupling partner with Pd(OAc)2 and Cul as an additive, although with slow reaction times (48 h) and high temperatures 140 °C (eq 60). ... 

Yoshida and coworkers developed a method for C-H nitrogenation of aromatics based on electrochemical oxidation of aromatic compounds in the presence of pyridine followed by the reaction of the resulting A -arylpyridinium ions with piperidine to selectively give aromatic primary amines as products [108]. This transformation provides a metal-free protocol for one-pot synthesis aromatic amines with broad functional groups compatibility (Scheme 2.10). 

In initial ICC studies, animals were treated with MDA or MDMA using the protocol described by Ricaurte et al. (1985). Adult Sprague-Dawley rats (150 to 200 g) reeeived subcutaneous injections of racemic MDA or MDMA every 12 hours for 4 days. Each dose was equivalent to 20 mg/kg of the free base. The rats were sacrificed by intracardiac aldehyde perfusion 2 weeks after the final dose. In order to study subacute effects for evidence of degeneration, additional rats received MDA every 12 hours for 2 days and were sacrificed 24 hours after the last injection. Additional experimental details are described elsewhere (O Heam et al. 1986 O Heam et al. 1988). A series of animals treated identically and in parallel were analyzed for changes in 5-HT levels and density of uptake sites using paroxetine binding (Yeh et al. 1986 Battaglia et al. 1987). 

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