Benzaldehyde, molecular structure

For the preparation of MIPM, the above phenol, 2,5-dimethoxyphenol was isopropylated with isopropyl bromide in methanolic KOH giving 2,5-dimethoxy-l-(i)-propoxybenzene as an oil. This formed the benzaldehyde with the standard Vilsmeier conditions, which melted at 77-78 °C from hexane and which gave a yellow malononitrile derivative melting at 171.5-173 °C. The nitrostyrene, from nitroethane in acetic acid was orange colored and melted at 100-101 °C from either methanol or hexane. This was reduced with lithium aluminum hydride in ether to give 2,5-dimethoxy-4-(i)-propoxyamphetamine hydrochloride (MIPM). The properties of the isolated salt were strange (soluble in acetone but not in water) and the microanalysis was low in the carbon value. The molecular structure had a pleasant appeal to it, with a complete reflection symmetry shown by the atoms of the amphetamine side chain and the isopropoxy side chain. But the nature of the actual product in hand had no appeal at all, and no assay was ever started. 

FIGURE 4 Molecular structure of (3-cyclodextrin covalently functionalized with the thiamine analogue (top). Schematic representation of its covalent anionic complexes formed with included benzaldehyde (bottom) (27-23). 

W(Tp)(NO)(PMe3)(r]2-benzene)] reacted with an excess of phenol to yield the two steroisomers of [W(Tp)(NO)(PMe3)(r]2-2H-phenol)] (Fig. 2.44), which in the presence of base and electrophilic species such as benzaldehyde, alkyl iodides, and Michael acceptors, is able to form new C-C bonds. Methyl and ethyl iodide react at C2 to form 2-alkyl-2H-phenol complexes, whereas the Michael acceptors react at C4 to give 4-alkyl-4H-phenol complexes. The crystal and molecular structures of the 2-ethyl-2H-phenol and of the phenyl o-quinone methide complexes have been reported.190... 

In the early days of chemical science, molecular structures were unknown for substances such as benzaldehyde (from almonds) and methyl salicylate (from oil of wintergreen). These compounds have distinctive aromas, so they came to be called aromatic." As chemistry developed, it was recognized that many of these aromatic compoimds contain a benzene ring. In time the term aromatic came to mean a certain kind of structure and not a distinctive odor. 

Reaction of benzaldehyde with 1 2 octanediol in benzene containing a small amount of p toluenesulfonic acid yields almost equal quantities of two products in a combined yield of 94% Both products have the molecular formula C15H22O2 Suggest reasonable structures for these products... 

Uncharged styryl (methine) disperse dyes were originally introduced to provide greenish yellow colours on cellulose acetate fibres. One such dye still in use is Cl Disperse Yellow 31 (6.226), which is made by condensing 4-(N-butyl-N-chloroethylamino)benzaldehyde with ethyl cyanoacetate. Suitable compounds for polyester usually contain the electron-accepting dicyanovinyl group, introduced with the aid of malononitrile. An increased molecular size leads to improved fastness to sublimation, as in the case of Cl Disperse Yellow 99 (6.227). A novel polymethine-type structure of great interest is present in Cl Disperse Blue 354 (6.228), which is claimed to be the most brilliant blue disperse dye currently available [85]. 

The (Z)- and ( )-styrylpyrazine structures 20j and 20k were assigned on the base of the mass, NMR, and UV spectral data. The mass spectrum of Z isomer (20j) shows a base peak (the molecular ion) at m/z 210 with a peak at m/z 133 formed by the loss of a phenyl group firom 20j. The H-NMR spectrum shows the presence of five aromatic and two olefinic protons in addition to one heteroaromatic proton and two methyl groups attached to the heteroaromatic nucleus. Ozonolysis of the Z isomer (20j) yields 3-formyl-2,5-dimethylpyrazine (487) and benzaldehyde, confirming the styryl moiety in 20j. The ( )-styryl derivative (20k) is readily isomerized to the Z isomer (20j) on exposure to sunlight (Scheme 60). Extraction of the pyrazines from I. humillis in the dark indicates that E isomer 20k is the naturally occurring product 144,145). 

Figure 7-19. Three examples of supramo-lecules formed from the assembly of two molecular species. In 7.33, the 1,4-butane-dioic acid is specifically hydrogen bonded to the bisamide. In 7.34, rc-stacking interactions between the cationic cyclophane and the host 1,4-dimethoxybenzene stabilise the structure, whilst in 7.35 the cavity of the ct-cyclodextrin host is the correct size for the benzaldehyde guest. In each case, hydrogen atoms have been omitted for clarity carbon atoms are grey, nitrogen atoms white and oxygen atoms black.

Treatment of benzaldehyde (CeHsCHO) with Zn(Hg) in aqueous HCI forms a compound Z that has a molecular ion at 92 in its mass spectrum. Z shows absorptions at 3150-2950,1605, and 1496 cm in its IR spectrum. Give a possible structure for Z. 

Mass spectrometry (MS) has been commonly used for the structure determination of substituted isoxazoles and their derivatives either to validate their molecular weight or to determine their structure. Regioisomeric 4,5-dihydroisox-azoles 13 and 14 were distinguished on the basis of their MS fragmentation pattern only the 5-phenyl isomer exhibits a peak MH -106 in the mass spectrum corresponding to the loss of benzaldehyde <1998JOC6319>. 

Structure-activity relationships have been largely employed for molecular design these correlations depend on the molecular representation and the activity landscape. The molecular representation depends only on the small molecule, whereas the activity landscape provides information on the ligand-receptor complex, for example, how permissive the binding pocket is. To exemplify the molecular similarity approach, a set of odorants (compared to benzaldehyde) will be presented. 

Amongst products isolated from Heliotropium spathulatum (Boraginaceae) were 9 mg of a new alkaloid which gave a positive Ehrlich reaction with p-dimelhylamino-benzaldehyde. The molecular formula determined by mass spectrometry is C15H25NO5. What is the structure of the alkaloid given the set of NMR results 49 Reference 31 is useful in providing the solution to this problem. 

The formation of [3]-rotaxane (136) does not involve any participation of the benzaldehyde derivative (132). As shown schematically in Figure 54, two molecules of prerotaxane (A) condense with two molecules of dipyrrylmethane in structure (C) the central stopper is a free-base porphyrin, which is shared by each threaded macrocycle, and the peripheral stoppers are gold(lll) porphyrins. The formation of [5]-rotaxane (149) is even more remarkable, because three porphyrins are formed simultaneously, involving the condensation in one molecule of 10 molecular precursors As before, the formation of the central porphyrin in (D) from two molecules of (B) does not involve the participation of 3,5-di-tert-butylbenzaldehyde... 

A number of low molecular weight products, for example, benzaldehyde, formic acid, formaldehyde, phenylglyoxal, phenylglyoxalic acid, and carbon dioxide, were identified among the products of thermal decomposition of the ozonides. A determination of the detailed structure of the polymer is possible from the qualitative analysis of these decomposition products. 

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