No abstract

retenequinone and anisaldehyde dissolved in 100 cc. of boiling absolute ethyl alcohol. The same procedure was Used as for the vanillin condensation. The product was recrystallized from dioxane, yield, 55%.#-(S',4'-Dimethoxyphenyl)retenoxazole (XVI). This compound was prepared from retenequinone and veratraldehyde dissolved in 100 cc. of boiling absolute ethyl alcohol. The same procedure was followed as for the vanillin condensation. It was recrystallized from dioxane, yield, 60%.g-(8',4'-Methylenedioxyphenyl)retenoxazole (XVII). This compound was prepared from retenequinone and piperonal dissolved in 100 cc. of boiling absolute ethyl alcohol. The same procedure was used as for the vanillin condensation. The product was crystallized from dioxane, yield, 62%.2-(a-Furfuryl)retenoxazole (XVIII). This compound was prepared from retenequinone and furfuraldehyde dissolved in 100 cc. of boiling absolute ethyl alcohol.At the end of thirty minutes, the reaction^mixture had set into a solid mass. After recrystallization from dioxane and then from alcohol, the compound was obtained as small, white needles, yield, 40%. Philadelphia, Pa. SUMMARY 1. The reaction of retenequinone and ammonia has been studied.2. A critical study has been made of the mechanisms previously assigned to the reaction of o-quinones and aromatic aldehydes in the presence of ammonia to form oxazoles and imidazoles.3. A.new mechanism, in agreement with• experimental findings, has been developed to explain the formation of 2-aryl retenoxazoles from retenequinone, aromatic aldehydes, and ammonia.4. A series of 2-aryl retenoxazoles and 2-aryl retenimidazoles has been prepared.

The ordinate of the frequency distribution is obtained by substitution of Equations 5 and 7 into 4:The beta distribution least squares fit to the cumulative distribution is given in Figure 1. The frequency distribution represented by Equation 10 is given in Figure 2.As a means of checking the procedure used in fitting the density distribution, the average density, 6, is calculated.Only the total volume, V , of the particles must be calculated from the frequency distribution since the total weight, W , was obtained experimentally:It is assumed that an infinitesimal interval change in the volume is given as :The right hand side of Equation 12 may be obtained by equating the right hand sides of Equation 10 and Equation 4. Then the relationship in Equation 7 is used. The final result is writtenThis equation was solved with the aid of the 16 point Gaussian quadrature formula (5,9).To check the values of the shape parameters, p and q, as obtained from least squares fitting of the experimental cumulative density distribution to the cumulative beta distribution, the values of p and q were changed by & 1 %, i 5 %, and =klOx, The average density was recalculated with the new values of p and q. With a change of + 1 % in p and q the calculated density remained unchanged. All calculations were performed on an IBM S/360, Model 44 computer. Double precision (16 significant figures) was used and was necessary for the evaluation of the beta function, the least squares procedure, and the evaluation of the integral in Equation 13. The pertinent data for two independent determinations on the same lot of glass beads are given in Table 111.From the results summarized in Table 111, it is clear that the least squares cumulative and frequency distributions, when used to calculate a mean density of the glass beads, give results in good agreement with the pycnometer results. The error in the calculated mean densities is comparable to that expected when densities are determined by Equation 1. Also, examination of Figure 1 indicates rather good agreement between the calculated and experimental distributions.Comparison of the results for the two independent determinations indicates good agreement between these two sets of measurements.

No abstract

A procedure is described for the assay of propoxur (o-isopropoxyphenyl N-methylcarbamate) by nuclear magnetic resonance (NMR) spectroscopy. Methanol was used as internal standard and chloroform as solvent. Known standard and technical materials were analyzed and results of NMR and liquid chromatographic methods were compared. The NMR method is straightforward, with a precision of ± 1.6% (95% confidence limits) for 2 sample weighings.