Erythrina alkaloids are a group of compounds found in plants of the Erythrina genus.
THEORETICAL PART6
However, 30 to 40 gbatches of (IX) were conveniently prepared by the reduction of homoveratronitrile with Raney nickel in ION methanolic ammonia, as described in the. 162-63°, which is about 70° lower than the melting point of the picrate of the decomposition product obtained from dihydroerysothrin. As it has been found difficult to reconcile this and other experimental evidence, collected by different workers in this laboratory, with the.
To test this hypothesis, the synthesis of the compound (C), namely 5-aza-4', 5'-dimethoxy-3-phenyl-benzocycloheptene, was attempted again. This oxidizing agent was found to be superior to potassium permanganate, as it not only gave a better yield but was also purer. Treatment of the diol (XVIII) with thionyl chloride in chloroform solution gave the dichloride (IXX).
The analytical results indicate that the product formed in the presence of sodium acetate is probably a diketopiperazine derivative. According to the new probable structure for the Erythrina alkaloids, mainly suggested due to the reinterpretation of the formation of.
6)Flow-sheet
The position of the halogen in 3-bromo-1-ethyl-2-nitrobenzene was proven by reducing it to 2-amino-3-bromo-1-ethylbenzene according to Kondo and Uyeo40 and oxidizing the latter's acetyl derivative with water. During the synthesis of 2,3'-diethyl-4,5-dimethoxy-2'-dimethylaminobiphenyl (XLI) it turned out to be interesting to An attempt was made to use α-ketoglutaric acid and α-ketoadipic acid as a further extension of the Pictet-Spengler reaction50.
[3-(3,4-dihydroxyphenyl)ethylamine (LIIl) was not found to react with it under physiological conditions. However, if an aqueous solution of amine and α-ketoglutaric acid at pH 1 is heated for 6 hours at 100 °C, lactam with the structure (LVI The latter was found to be a crystalline compound m.p. About 960 g of extract (obtained from about 3.5 kg of these seeds of Erythrina abyssinica Lam. by extraction first with petroleum ether and then with methanol) were treated as described by V. Prelogetal52. The chloroform extracts were discarded and the aqueous solution was adjusted to pH 7-8 with a 50% aqueous sodium bicarbonate suspension.
PKA ~ 3.5
- mm (bath temperature 180°) when 20 mg of a yellow, viscous oil
- Phenylacetyl-homoveratrylamine (X)
- Tosyl-homoveratrylglycine (XXII)
The picric acid that precipitated on cooling was filtered and the filtrate was extracted with nitro. with benzene and then with ether. The aqueous solution was evaporated to dryness in vacuo when the hydrochloride crystals were brown in color. The hydride was obtained by adding potassium iodide to a solution of the base in dilute hydrochloric acid. After two crystallizations from water, it melted at 196-97 °. It was dried for 72 hours for analysis.
The alkaline filtrate was acidified with sulfur dioxide and after cooling the white precipitate was filtered off, washed with water and dried. The excess benzene was removed in vacuo and the solid residue was filtered and washed with water. The solid residue was washed with water and crystallized from dilute alcohol to obtain 5.2 g of colorless needles.
The 2,4-dimitrophenylhydrazone was prepared by boiling the alcoholic solution of the keto ester with a solution of 2,4-dinitrophenylhydrazine containing a few drops of concentrated hydrochloric acid for two hours. In all cases, only mixtures containing 0.1 to 0.9 % nitrogen were obtained; the pure dinitrile could not be prepared. It was filtered and washed with a little glacial acetic acid and then with dry ether.
The analysis of this picrate is consistent with that of a dipicrate (addition product) of the diketopiperazine that could have formed above. It was obtained by the nitration of veratraldehyde76 according to the modified method of Cassaday and Bogert77. The mixture was heated on a steam bath for two hours with regular agitation and filtered through celite.
The residue was poured into water containing sufficient ammonia to ensure dissolution of the acid. Most of the methanol was removed by distillation and the resulting solution was filtered through celite. The residue was dissolved in ether and the ether solution was washed successively with 20% sodium thiosulfate solution, 2N sodium hydroxide and water.
After standing for fifteen minutes at 20°, the reaction mixture was shaken with ether and the ether solution S9 was washed successively with water, 2 N sodium hydroxide. The temperature of the mixture was gradually raised and maintained between 235-40° for 30 minutes with stirring frequent. The mother liquor from above after removal of alcohol was fractionally distilled to 0.01 mm (bath temperature to . 155°) on a Kraig column. The fractions collected at different temperatures consisted of the starting materials and their mixtures.
Two crystallizations from methanol (charcoal) gave colorless crystals, m.p. analysis, it was crystallized five times from methanol and sublimed. In addition, this substance was reduced to 2-amino-3-bromo-1-ethylbenzene. of the amine when crystallized from dilute methanol, melted at 121-22°C. This acetyl derivative was oxidized with a dilution. solution of potassium permanganate as described by the above authors, when 2-acetylamino-3-bromobenzoic acid with m.p. Ullmann reaction of 4-ethyl-5-iodoveratrol and 3-bromo-1-ethyl-. 0.005 mol) 3-bromo-1-ethyl-2-nitrobenzene was heated to 170°C in a graphite bath and 2.3 g of copper powder was added in small portions over 10 minutes with stirring.
2 OCH3 10.74 2 N-CH35.20 %
OCH3 10.75 N-CH35.36 %
- g of copper powder was added to it with stirring during an interval of 10 minutes. The temperature of the reaction mixture was gradually
It was dissolved in methanol and boiled with animal charcoal for 15 minutes. Evaporation of the filtrate gave 20 mg of yellow. After cooling, the solution was filtered and most of the alcohol was removed from the filtrate by distillation. Treatment with diazomethane in a methanol-ether suspension gave the methyl ester of the dimethyl ether.
The filtrate deposited slightly yellow crystals on cooling. The above procedure was repeated twice without the addition of charcoal and the crystals were washed with cold water until acid was free.
SUMMARY
Dihydroerysotrine (dihydroerysodine methyl ether) on treatment
According to the new structure proposed for the Erythrina alka¬
The Hofmann degradation of apoerysopine was carried out accor¬
To compare it with tetrahydro-des-dimethyl apoerysotrine, the syn¬
A study of the synthesis of uns>mmetrical biaryls by the Ullmann
Compounds similar in structure to the Erythrina alkaloids were ob¬
CURRICULUM VITAE
