Formamide chemistry

Formamide chemistry. Production of formamide from methyl formate is accomplished by reacting anhydrous ammonia with methyl formate at 65°C (150 F) and 13 bars (190 psig). 

Saladino R, Crestini C, Ciciriello F, Costanzo G, Di Mauro E Formamide chemistry and the origin of informational polymers. Chem Biodivers 2007, 4(4) 694-720. 

Volumen and Hydratationswarme der lonen. Zeitschrift filr Physik 1 45-48. aan C M and K B Wiberg 1990. Determining Atom-Centred Monopoles from Molecular Electro-itic Potentials. The Need for High Sampling Density in Formamide Conformational Analysis. imal of Computational Chemistry 11 361-373. 

With optically active formamide-derived aminocarbene complexes high enantioselectivity was observed in most cases (Table 5). This chemistry was used in the synthesis of 1-carbacephalathin and 3-ANA precursors (Eq. 9) [48], as well as the synthesis of a,a -disubstituted amino acids (Scheme 1) [49]. 

In 2001, Sarko and coworkers disclosed the synthesis of an 800-membered solution-phase library of substituted prolines based on multicomponent chemistry (Scheme 6.187) [349]. The process involved microwave irradiation of an a-amino ester with 1.1 equivalents of an aldehyde in 1,2-dichloroethane or N,N-dimethyl-formamide at 180 °C for 2 min. After cooling, 0.8 equivalents of a maleimide dipo-larophile was added to the solution of the imine, and the mixture was subjected to microwave irradiation at 180 °C for a further 5 min. This produced the desired products in good yields and purities, as determined by HPLC, after scavenging excess aldehyde with polymer-supported sulfonylhydrazide resin. Analysis of each compound by LC-MS verified its purity and identity, thus indicating that a high quality library had been produced. 

Such one-center enhancement effects can be illustrated by formamide 5 for nb—>7Ta (3.109c) interactions. As shown in Table 3.19, the n — -7tco interaction of 5 leads to strong conjugative stabilization (59.8 kcal mol-1) and reduced C—O bond order (1.732), the famous amide resonance of peptide chemistry ... 

The RAHB effect may be illustrated by the ubiquitous C=0- -H—N hydrogen bond of protein chemistry. As shown in Section 5.2.2, the simplest non-RAHB prototype for such bonding, the formaldehyde-ammonia complex (5.31c), has only a feeble H-bond (1.41 kcalmol-1). However, when the carbonyl and amine moieties are combined in the resonating amide group of, e.g., formamide, with strong contributions of covalent (I) and ionic (II) resonance structures,... 

Several studies have been concerned with the chemistry of the + ni oxidation state of these elements, and the characterization of the first tantalum(iii) compounds has been claimed. The diamagnetic dimer [TaCl3(MeCN)2]2 has been prepared and used to obtain [TaClafphen)], [TaCljfbipy)], and tris-(dibenzoylmethanato)tantalum(ni). NbFa has been characterized as the product of the reaction of Nb and NbF (1 1) at 750 °C under pressure. Electrolytic reduction of niobium(v) in ethanol,formamide, and dimethylformamide can afford preparative concentrations of niobium(iii) and the new compound niobium(iii) trilactate has been obtained from ethanol. 

Cycle sequencing products need to be purified, for example by ethanol precipitation prior to loading onto the sequencer. For this purpose, 80 pi water and 10 pi of 3 M sodium acetate are added to each tube or well, and the DNA is precipitated with 250 pi of ethanol. Incubate for 15 min at room temperature and spin for 20 min at maximum speed. The supernatant is removed carefully and 250 pi of 70% ethanol is added. Spin again for 15 min at maximum speed. The pellet (unusually not visible) is air-dried and may be resolved, for example in 20 pi Hi-Di formamide for transfer to the sequencing instrument. For detailed instructions, refer to the respective user s manual or chemistry guide. 

This section deals with the coordination chemistry of amides of carboxylic acids, predominantly formamide, acetamide and their -substituted derivatives. Lactams are also mentioned briefly. 

The commercial production carried out by various companies is estimated to be ca. 2000 tyear-1 worldwide [7]. Due to the common solubility in water and various other solvents (e.g. DMSO, formamide), the biocompatibility, and the ability of degrading in certain physical environments, dextran is already successfully applied in the medical and biomedical field [8]. The physiological activity of dextran and its derivatives, indicated also by a very large number of publications in this area of research, is in contrast to inadequate structural analysis of both dextran and their semi-synthetic products. Only a few publications, in contrast to extensive studies in cellulose and starch chemistry [9,10], deal with the defined functionalisation and characterisation of dextran for adjusting desired features. 

The amidation of unsaturated acids or esters (not necessarily a,(3 unsaturated ones) leads to derivatives of the corresponding dicarboxylic acids and may serve as a method for the synthesis of dicarboxylic acids from unsaturated monocarboxylic acids (10,13, 14). This reaction of formamide with oc,(3-unsaturated acid derivatives besides being of synthetic value has some interesting aspects as far as free radical chemistry and photochemistry are concerned. We shall start this section in discussing the last point, i.e. the photochemical aspects of the reaction. This point is of primary interest to the synthetic organic chemist, who must be aware of it, otherwise he may fail in his synthetic work purely because of photochemical reasons. 

Non-aqueous synthetic methods have recently been used to assemble mesoporous transition metal oxides and sulfides. This approach may afford greater control over the condensation-polymerization chemistry of precursor species and lead to enhanced surface area materials and well ordered structures [38, 39], For the first time, a rational synthesis of mesostructured metal germanium sulfides from the co-assembly of adamantanoid [Ge4S ()]4 cluster precursors was reported [38], Formamide was used as a solvent to co-assemble surfactant and adamantanoid clusters, while M2+/1+ transition metal ions were used to link the clusters (see Fig. 2.2). This produced exceptionally well-ordered mesostructured metal germanium sulfide materials, which could find application in detoxification of heavy metals, sensing of sulfurous vapors and the formation of semiconductor quantum anti-dot devices. 

Radical nucleophile oxidation based on one-electron oxidation, known as the Minisci reaction, is employed for the functionalization of /V-heterocycles with acidic hydrogen peroxide in the presence of iron(II) salts (Figure 3.112).472 A range of A-heterocycles (pyridines, pyrazines, quinolines, etc.) which are activated towards attack by nucleophilic radicals when protonated are suited to this chemistry. The Minisci reaction is suitable for the preparation of carboxylic amides (from formamide), carboxylic esters (from pyruvic esters via a hydroxyhydroperoxide), aldehydes (from 1,3,5-trioxane) and alkylated pyridines (either from carboxylic acids or from alkyl iodides in dimethyl sulfoxide).473 The latter reaction uses dimethyl sulfoxide as the source of methyl radical (Figure 3.112). 

Siliranes have been used as helpful intermediates in organic synthesis. 7ra t-Insertion of formamides into a C-Si bond of silirene 50 provides a facile route to the oxasilacyclopentane acetate in 86% yield (Equation 8). The authors claim that the chemistry of silirenes will lead to new methods for the synthesis of polyoxygenated natural products <1997T16597>. 

One of the most significant processes that involve CO in organic industrial chemistry is the hydroformylation of alkene, or the 0x0 process, in which rhodium and cobalt complex catalysts are used. Ruthenium is a strong candidate for replacing the very expensive rhodium catalyst. Further, ruthenium complexes are excellent catalysts for the addition of formyl groups of aldehydes, formates and formamides to alkenes. 

Some recent developments in the research of the structure and dynamics of solvated ions are discussed. The solvate structure of lithium ion in dimethyl formamide and preliminary results on the structure of sodium chloride aqueous solutions under high pressures are presented to demonstrate the capabilities of the traditional X-ray diffiraction method at new conditions. Perspectives of solution chemistry studies by combined methods as e.g. diffraction results with reverse Monte Carlo simulations, are also shown. 

Polyvinylpyrrolidone (PVP) is a synthetic polymer derived from the Reppe chemistry and is widely used in the pharmaceutical, personal care, cosmetic, agriculture, beverage, and many industrial applications. PVP is a polar and amorphous polymer which is soluble in water and some organic solvents, such as alcohols, chlorinated hydrocarbons, dimethyl formamide, dimethyl acetamide, and V-methyl pyrrolidone. 

The dimer is not readily soluble in water, although DHA is very soluble in water. Thus some questions have arisen as to the exact nature of BDHA in water. The dimer disassociates to a monomer in dimethyl formamide, dimethylacetamide, and pyridine (44) in agreement with earlier studies (45-47), A series of studies of AA and BDHA have now clarified many aspects of this problem. NMR studies of AA were published (48-51) that show the structure of AA in solution is essentially as proposed by classical carbohydrate chemistry and is the same as the structure found in crystalline ascorbic acid by x-ray crystallographic studies. Recent NMR studies of BDHA in dimethyl sulfoxide-de (DMSO-de) show that in this solvent BDHA is a mixture of two forms, a symmetric and an asymmetric dimer (52), The asymmetric form is thermodynamically favored. 

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