No abstract

To determine in more detail the reaction of Folin-Ciocalteu phenol reagent with nitrogen compounds, a number of hydroxylamine-related compounds and a large number of guanidine-containing compounds were tested. In general, guanidine compounds did not react strongly unless they were hydroxyamino or hydrazino derivatives. The non-hydroxyamino paralytic shellfish poison saxitoxin, however, reacted to a significant extent. This may be due to the presence of a five-membered ring structure and its analogy to 2-aminopurines, which react strongly. A number of simpler amines were also tested. Tertiary aliphatic amines, but not primary, secondary, or quaternary amines, reacted strongly with the reagent. Primary, secondary, and tertiary aromatic amines all reacted strongly with the reagent. Reactivity was extended to pyrroles and indole derivatives but not to imidazole and benzimidazole derivatives. Defining the reactivity of Folin-Ciocalteau phenol reagent with nitrogen compounds extends the usefulness of the reagent for the detection and determination of certain nitrogen compounds in basic extracts by colorimetric means and by thin-layer chromatography.

Experiments were run to determine the effect of filtrate from incubated Aphanizomenonflos-aquae on the thoracic appendage beat rate and frequency of postabdominal rejections by Daphnia carinata. Comparisons were made between the response to Aphanizomenon filtrate and to purified saxitoxin (STX). The short-term response pattern to the filtrate included an immediate 30-50% depression of thoracic appendage beat rate and elevation of postabdominal rejection rate followed by slowly decreasing thoracic appendage beat rate and increasing postabdominal rejection rate during the 1 O-min exposure. Animals recovered to pretreatment activity rates in <5 min. A similar response was observed in STX, except that Daphnia began to recover immediately from the thoracic appendage beat rate inhibition. Animals recovered to -60% of pretreatment activity after l-2 h in Aphanizomenon filtrate, whereas in STX they returned to pretreatment activity levels after -1 h of exposure to the neurotoxin. Water from a lake with a winter bloom of A. Jlos-aquae produced the same pattern of thoracic appendage beat rate and postabdominal rejection rate response as seen with the cultured Aphanizomenon. A comparison of responses to STX and the Aphanizomenon filtrate indicates the effect on D. carinata is through chemosensory stimulation rather than neuromotor inhibition.

Vol. 66 lated: 0.31 g. of VIII (63%); 0.19 g. of II (35%); 0.20 g. of salicylic acid and traces of carbomethoxysalicylic acid. One gram of the ester under the same conditions yielded 0.18 g. of VIII after refluxing for five minutes.3,3' -Methylenebis -(4 -hydroxycoumarin) dibenzoate (1.12 g.) in 12 ml. of absolute ethanol was refluxed with 2 moles of sodium ethoxide for fifteen hours. Two moles of 1 N hydrochloric acid was added and the combined precipitate of II and VIII was filtered off and II separated from VIII by means of its solubility in dilute NaOH. VIII (0.13 g.) m. p. 318-320°and II (0.56 g.) m. p. 290°w ere obtained. One mole of NaHCOs was added to the filtrate and after concentration to dryness in vacuo, the residue was acidified and extracted with ether. The acid fraction yielded 0.12 g. of benzoic acid, m. p. 118-120°, and the neutral solution yielded 0.02 g. of ethyl benzoate, b. p. 206-207°.3,3'-Methylenebis-(4-hydroxycoumarin) Disalicylate.-The di-(o-benzyloxybenzoate) of I (3.9 g.) in 200 ml. of dioxane was hydrogenated at 1900 pounds pressure and 100°for three hours over Raney nickel. The catalyst was filtered off and the filtrate concentrated to dryness in vacuo.The residue was taken up in a small volume of hot dioxane and the insoluble residue of II was filtered from the hot solution. This process was repeated three times. After a final recrystallization from acetic acid the disalicylate.of II melted at 223-225°, yield 0.7 g.

No abstract