Formamide structure

Polyamides and Polyimides - The dominant structure formed in the photodegradation of nylon 6,6 is the terminal methyl group associated with main chain scission. Aldehyde and formamide structures have also been identified along with evidence for hydroxylation adjacent to the amide group. The forma-... 

The 2c list (BOND... END) entries consist of bond-multiplicity descriptors (S = single, D = double,...) followed by atom center numbers of the two bonded atoms (such as S 1 2 for a single bond between atoms 1 and 2, etc.) for example, the BOND list for formamide structure (5.24) (with triple bond between N2 and O3 and single bonds N1-H4, N1-H5, and C2-Hg) can be specified as... 

Two Lewis structures (resonance forms) of formamide the atoms are connected in the same order but the arrangment of the electrons is different... 

Poly(7-benzyl-L-glutamate) is known to possess a helical structure in certain solvents. As part of an investigationf of this molecule, a fractionated sample was examined in chloroform (CHCI3) and chloroform saturated ( 0.5%) with dimethyl formamide (DMF). The following results were obtained ... 

Examine the geometry of formamide. Is the CN bond shorter than expected for a normal single bond (in methylamine), and closer to that expected for a full double bond (in methyleneimine) Is the CO bond longer than that expected in a carbonyl compound (in formaldehyde), perhaps closer to that appropriate for a single bond (in methanol) Also, compare the electrostatic potential map for formamide with those of formaldehyde and methylamine. Is the CO bond in formamide more or less polar than that in formaldehyde Is the CN bond in formamide more or less polar than that in methylamine Draw whatever Lewis structures are needed to properly describe the geometry and charge distribution of formamide. 

In an initial step the reactive formylating agent is formed from N,N-dimethylformamide (DMF) 2 and phosphorus oxychloride. Other N,N-disubstituted formamides have also found application for example A -methyl-A -phenylformamide is often used. The formylating agent is likely to be a chloromethyl iminium salt 4—also called the Vilsmeier complex (however its actual structure is not rigorously known)—that acts as the electrophile in an electrophilic substitution reaction with the aromatic substrate 1 (see also Friedel-Crafts acylation reaction) ... 

Samal et al. [25] reported that Ce(IV) ion coupled with an amide, such as thioacetamide, succinamide, acetamide, and formamide, could initiate acrylonitrile (AN) polymerization in aqueous solution. Feng et al. [3] for the first time thoroughly investigated the structural effect of amide on AAM polymerization using Ce(IV) ion, ceric ammonium nitrate (CAN) as an initiator. They found that only acetanilide (AA) and formanilide (FA) promote the polymerization and remarkably enhance Rp. The others such as formamide, N,N-dimethylformamide (DMF), N-butylacetamide, and N-cyclohexylacetamide only slightly affect the rate of polymerization. This can be shown by the relative rate (/ r), i.e., the rate of AAM polymerization initiated with ceric ion-amide divided by the rate of polymerization initiated with ceric ion alone. Rr for CAN-anilide system is approximately 2.5, and the others range from 1.04-1.11. 

Non-aqueous microemulsions have been prepared by replacing water with formamide, a highly structured polar solvent [71]. Formamide enhances the solubility of organic compounds and is also used as a reactant. 

Dynamic light-scattering experiments or the analysis of some physicochemical properties have shown that finite amounts of formamide, A-methylformamide, AA-dimethyl-formamide, ethylene glycol, glycerol, acetonitrile, methanol, and 1,2 propanediol can be entrapped within the micellar core of AOT-reversed micelles [33-36], The encapsulation of formamide and A-methylformamide nanoclusters in AOT-reversed micelles involves a significant breakage of the H-bond network characterizing their structure in the pure state. Moreover, from solvation dynamics measurements it was deduced that the intramicellar formamide is nearly completely immobilized [34,35],... 

British Biotech has described co-crystal structures of both BB-3497 and actinonin bound in the active site of E. coli PDF [24]. The metal centre (Ni ) in both complexes adopts a pentacoordinate geometry, bound by the two oxygen atoms of the hydroxamate along with Cys-90, His-132 and His-136. This coordination pattern is consistent with the mechanism of de-formylation proposed by Becker et al. [56] and Jain et al. [67], in which a pentacoordinated metal centre stabilises the transition state during hydrolysis of the formamide bond. When compared to the co-crystal structure of a substrate hydrolysis product, Met-Ala-Ser, it is clear that the side chains of these two inhibitors bind into the active site pockets similarly to the substrate [56]. 

Florian, J., Johnson, B. G., 1995, Structure, Energetics, and Force Fields of the Cychc Formamide Dimer MP2, Hartree-Fock, and Density Functional Study , J. Phys. Chem., 99, 5899. 

In the photoaddition of 2-pyrrolidone the 5-alkyl isomer (69) always predominates, usually in a ratio of 2 1. The formation of anti-Markovnikov 1 1 adducts, telomers, and dehydrodimers of structure (71) supports a free radical mechanism. Similarly, formamide undergoes olefin addition under... 

Closer inspection of the blocks in the crystal structure, however, reveals some interesting variation as far as the individual spatial arrangements are concerned. The most compact association is found in the 1 2 inclusion compound of the spiro host 22 with dimethylformamide48> (Fig. 23, type la). This aggregate preserves a perfect twofold (C2) molecular symmetry in the crystal lattice. The formamide moiety acts as... 

Kitano, M., and K. Kuchitsu. 1974. Molecular Structure of Formamide as Studied by Gas Electron Diffraction. Bull. Chem. Soc. Japan 47, 67-72. 

Consider, for example, the simple structure of formamide (Fig. 7.8). Albeit more than twenty years old, the combined electron diffraction and microwave study of this compound (Kitano et al. 1974G), is still state-of-the-art in the sense that no investigation of this kind has been performed with higher resolution. The experimental structure is characterized by... 

Fig. 7.8 Structural parameters for formamide determined from gas-electron diffraction (values with uncertainty estimates in parentheses taken from M. Kitano and K. Kuchitsu, Bull. Chem. Soc. Japan, 47 (1974) 67) and HF/4-21G calculations (values taken from H. L. Sellers, V. J. Klimkowski, and L. Schafer, Chem. Phys. Lett. 58 (1978) 541).

Methoxypurine was found to crystallize as a hemihydrate from /V,/V -dimethyl formamide, and as a trihydrate from water [63]. Thermal treatment of the trihydrate could be used to obtain the hemihydrate. Zafirlukast was obtained in the form of monohydrate, methanol, and ethanol solvatomorphs, with the drug substance adopting a similar conformation in all three structures [64], In the isostructural methanol and ethanol solvates, the solvent molecules are hydrogen-bonded to two zafirlukast molecules, while in the monohydrate, the water molecules are hydrogen-bonded to three zafirlukast molecules. The structures of the acetone and isopropanol solvatomorphs of brucine have been reported, where the solvent controlled the self-assembly of brucine on the basis of common donor-acceptor properties [65],... 

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