Lactones, absorption bands

A concentrated hydrochloric acid (20ml) slurry of ID-MA copolymer (5.0g) was stirred and heated for 6 hr. at 50°C. The polymer was collected, air dried, dissolved in DMF, reprecipitated from diethyl ether and dried in vacuo to obtain a 3.66g yield of tan colored material. The IR spectrum exhibited expected cyclic lactone absorption bands at 1760 and 1165 cm-1 region. 

Considering elemental analyses data, infrared absorption spectra with strong lactone absorption bands at 1 730-1 750 cm and carboxyl OH at 2 500-2 700 cm solubility, and other factors for the various copolymers, structure 4 was assumed for the various materials. 

The IR spectra of carbohydrazide 9 showed absorption bands at 3317 cm (OH,Hydrazide NH2), 3269 cm (aromatic CH), 1711 cm (CO stretching), and 1621-1640 cm (CO-NH-NH2 groups). The H NMR spectra exhibited a singlet due to the CONHNH2, NH proton at 9.32 ppm. Methylene protons resonated as a singlet at 4.23 ppm. The structures of the products lOa-1 were inferred from their analytical and spectral data. Thus, their IR spectra showed characteristic absorption bands at 3400-3240 cm (NH,OH), 1710-1700 cm (lactone CO), and NHCO at 1650-1600 cm . ... 

The hydrolysis of the cyclic acetal, which was used as the connecting group between the polymer chain and the lipid, was confirmed both by the IR and the proton NMR spectra of the lipid recovered from the vesicular system after standing for 3 weeks at room temperature. The lactone absorption at 1805 cm-1 disappeared from the IR spectrum (Figure 6) as the result of hydrolysis. Furthermore, a new aldehyde absorption band at 1705 cm 1 was observed in the spectrum, which is related to the substituted benzaldehyde group of the hydrolyzed product. The proton NMR spectrum (Figure 10) also clearly showed the formation of the benzaldehyde, as indicated by the peak at 810.20 ppm. 

Xanthene dyes are used as colour formers. These so-called fluorans usually contain amino groups sited para and meta to the central carbon atom. Such a substitution pattern gives rise to broad absorption bands and leads to almost black colour production the lactone 6.200 is a typical example. This xanthene derivative finds use in direct thermal printing [36]. The chemistry of fluoran leuco dyes has been reviewed [78]. 

The carbonyl group. Acetone (in cyclohexane solution) exhibits two absorption bands one appears at 190nm (e 1860) and corresponds to the n - n transition, while the second is at 280 nm (e 13) and corresponds to the n - n transition. The absorption maxima of these bands are solvent-dependent. Ultraviolet spectra of saturated aldehydes, carboxylic acids, esters and lactones exhibit a similar absorption profile, and in general are of little diagnostic value. 

Daphmacropodine [19 mp 215-218° (as hydrobromide) [a]D +4.9° (in CHC13) m/e 513, 286, and 272] has also been isolated from the bark of D. macropodum together with daphmacrine (18). This alkaloid has an acetoxyl group (pmax 1740 and 1240 cm-1) but any IR absorption band resulting from a five-membered lactone, which can be found in the case of the alkaloid 18, is not observed. The NMR spectra of both alkaloids are quite similar except for the appearance of a singlet at 4.78 in daphmacropodine which can be assigned to the one proton of... 

A fulgenolide is a kind of lactone. When R2 is an aromatic group, only the L isomer (9) has photochromic behavior. Fulgenates have excellent photochromic properties, but the absorption band is blue shifted compared with that of the corresponding fulgide. 

The enaminoketone structure of compound 220 in the crystal state was derived from the IR spectrum which contained the following absorption bands 1760 (ester carbonyl), 1640 (exocyclic carbonyl group), 1630 (lactone carbonyl in the pyran ring), and 3350 cm (strongly broadened z(N-H) band) <2001RJ01318>. 

In the carbonyl region, at a weak extent of conversion, photooxidation of ABS and BR led to the formation of a thin absorption band with maxima at 1697 cm-1 (a, (3-unsaturated acids) and 1683 cm-1 (a, (3-unsaturated ketone), and to the formation of a broader absorption band with a maximum at 1721 cm-1. As photooxidation proceeded, the intensity of this latter band increased and shifted to 1717 cm-1 whilst the band at 1697 cm-1 became hard to observe. The intensity of the band at 1697 cm-1 ceased to increase after 16 h of irradiation. When the exposure time was longer than 22 h, only one absorption band was observed. Its maximum shifted from 1717 to 1725 cm-1. In parallel, a shoulder was detected in the range 1775-1785 cm-1. It was shown that the absorption around 1725 cm-1 resulted from the convolution of various species saturated carboxylic acid (1717 cm - ), aliphatic ester (1735 cm-1), a, (3-unsatur-ated anhydride (1724-1782 cm-1), saturated aldehyde (1727-2720 cm-1) and saturated ketone (1725 cm-1). The maximum at 1780 cm-1 has been assigned to three types of structure a, (3-unsaturated anhydride (1724 and 1782 cm-1), perester (1789 cm-1) and 7-lactone (1775 and 1175 cm-1). 

The IR spectra of an AES film recorded in the hydroxyl vibration region during the first 38 h of irradiation showed an increase in a broad absorption band centered around 3450 cm-1 attributed to hydroperoxides. The development of a complex band with a maximum at 1713 cm-1 and shoulders around 1690, 1730 and 1770 cm-1 was observed in the carbonyl vibrations region (Figure 30.6). These maxima correspond to carbonylated photoproducts that have been previously identified during photooxidation of EPDM [17] and ethylene-propylene copolymer [18]. The bands at 1713, 1730 and 1770cm-1 correspond, respectively, to the absorption of saturated acids (dimer form) and ketones, esters and lactones or peresters the absorption around 1690 cm-1 is related to the presence of unsaturated carbonyl species. 

FTIR spectroscopy. Several absorption bands are mentioned in the literature [9-11] and attributed to vibrational properties of different surface groups. It is important to stress that this method does not make the difference between identical groups of different strength. In this section, we will only focus on the common features of the support and the catalyst. The phenolic groups seem to be more numerous than the others (quinonic, carboxylic, lactonic). The nitric treatment seems to increase the amount of quinonic groups on the support, and the quinonic and phenolic ones on the catalyst. Those results are in accord with these obtained in the Boehm titration. At this moment, we have no direct information on the basic surface groups. 

From the MeOH extract of the branches of Tripterygium doianum 3p-acetoxy-1 l-ursen-13a,30-olide was isolated (34) [52], Its IR spectrum exhibited absorption bands for a lactone carbonyl and a carbonyl group. Based on its H and l3C NMR spectroscopic data, compound (34) was assumed to be an ursene-type triterpene. The compound showed signals for a lactone group, an acetoxy group and a double bond. 

In contrast to aliphatic esters or lactones which only show end absorption around 230 nm, thiolesters exhibit a strong absorption band with X 235 nm, corresponding to a n-n transition [16]. Conjugation of the C(0)S group with an additional C=C double bond shifts the maximum to 265-270 nm as illustrated for 2(3//)-thiophenones [17] or 2(5/I)-thiophenones [18] (Scheme 2). These latter compounds exhibit an additional n-ci absorption band at X 320 nm. 

I.R. spectrum of heat-treated 4,4 -dibenzamido-6-ethoxycarbnyl benzanilide(Fig. 3) showed a strong lacton carbonyl absorption band at 1,746 cm and ether absorption band at 1,053 cm, suggesting the formation of benzoxazinone derivative by the ethanol elimination reaction between ethoxycarbonyl group and amide bond. 

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