sample was worked up in the usual manner and the nmr spectra were recorded in CDC13.Attempted Reactions of 2a-c with Hydrazoic Acid. Sodium azide (0.02 mol) was allowed to react with a slight excess of hydrobromic acid in 50 ml of DMF at room temperature for 10 min. Then 0.02 mol of 2a-c was added and the mixture was stirred for the same time as given in procedure B. The nmr spectra, after work-up, indicated no reaction. The -bromovinyl ketones 2a-c were recovered in 76-86% yield.Dehydrobromination of la-c. Dibromides la-c (0.1 mmol) and 0.2 mol of sodium acetate were stirred in 200 ml of dry DMF at room temperature for the appropriate reaction time (0.5 hr for la, 5 hr for lb, and 1 hr for lc). After work-up the following yields were obtained: 90% 2a in a cis/trans ratio of 80/20, 90-92% cis-Vo, and 89% 2c in a cis/trans ratio of 60/40.Cis-trans Isomerization of Vinyl Bromides 2. cfs-a-Bromoethylideneacetophenone (2a) isomerized spontaneously and quantitatively into trails-2a (mp 66.5-67.0°, petroleum ether) within 1 day upon standing at room temperature. When rá-a-bromochalcone (2b) was heated under nitrogen at ca. 160°for 1 hr, the nmr spectrum showed a large decrease of the 2.87 absorption relative to the aromatic multiplet indicating a cis/trans ratio of about 30/70. This reaction mixture was allowed to crystallize from zz-hexazie at low temperature, and yielded trans-2b as a pale yellow crystalline product, mp 38-39°( lit.10 mp 42°).
Multiple regression is widely employed to study the contribution of components to the toxicologic effect of a mixture. Here, use is made of the fact that data obtained from standard curves of substances and from their mixtures are separable in regression analysis. Thus, under an assumption of additivity of responses, regression coefficients obtained for components in mixtures alone should be the same as for the individual substances. A t-test is developed such that nonsignificant t values support additivity, negative significant values support antagonism, and positive significant values support synergism. The results are applied to data on the mutagenicity of binary mixtures of azaserine, 4-nitroquinoline N-oxide, and 9-aminoacridine in TA 100 in the Ames assay.
Notes (0.35 mm) [lit.9 73°,(2.0 mm), 37% yield by Na reduction],Trans Esters. The trans esters in Table I were all prepd in the usual manner by addn of the acid chloride in PhH to the alcohol and Et3N in PhH. Nmr (CDC13) spectra of all trans esters were similar to that of the alcohol. Under triple irradiation, decoupling both CH2 groups, the vinyl protons of the morpholino pivalate appeared as a singlet (half-bandwidth 3 Hz).4-Amino-2-butyn-l-ol Esters. The esters in Table II were prepd as above for the trans esters from the corresponding alcohol and acid chloride.Cis Esters. The cis esters in Table I were prepd by redn with H2 and 5% Pd/C in EtOH at room temp and atm pressure to the theoretical amt. Usual work-up and distn; nmr (CDC13) 6.04 (octet, 2, half-bandwidth ~28 Hz). Triple irradiation, as above, showed a quartet (/ab =11.5 Hz).
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