Long chain N-acylglutamic acid was prepared in a high yield by a reaction of glutamic acid with fatty acid chloride in a mixed solvent of water and a water miscible organic solvent such as acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, t-butyl alcohol or cyclohexanone. In this reaction the composition of the mixed solvent influenced the yield of N-acylated glutamic acid and the best yield was obtained when the reaction was carried out in the mixed solvent comprising 30-60% v/v of the organic solvent. Long chain N-acylaspartic acid was also obtained in a high yield by the same method. As the other method to obtain N-lauroyl-DL-glutamic acid, it was examined that N-acyl-ot-aminoglutarodinitrile which was obtained by a reaction of a-aminoglutarodinitrile with fatty acid chloride was hydrolyzed with an aqueous alkaline solution. The salts of long chain N-acylglutamic acid are known as the surface active agents that react mildly on the human skin. 157

The physicochemical properties of long chain N‐acylglutamic acids (AGA) and their sodium salts (AGSn) are described. The solubility, Krafft point, pH value, critical micelle concentration, surface tension and foaming power were measured. The properties of the optically active AGA or AGSn differed from those of the corresponding racemates, especially in solubility. The monosodium salts generally had high Krafft points, but monosodium N‐oleoylglutamate had a low Krafft point. The monosodium salts hydrolyzed in the diluted aqueous solution to liberate the AGA. The aqueous solutions of the monosodium salts had low surface tensions and good foaming properties. The disodium salts were highly soluble in water, while surface tensions and foaming properties were inferior to those of the corresponding monosodium salts.

Optically active '-acylamino acids formed a new type of lyotropic cholesteric liquid crystals when they were swelled and dispersed as a suspension in solvents such as benzene, chlorobenzene, chloroform, and «-hexane. An appropriate solvating ability to swell but not to dissolve any given '-acylamino acid may be a necessary condition for a solvent to form the liquid crystalline phase which appears as a suspension. These suspended liquid crystals showed some characteristics of lyotropic cholesteric liquid crystals: (1) circular dichroism (CD) bands with a single sign, (2) the liquid-crystal-induced CD (LCICD) bands due to achiral molecules added to these systems, and (3) a spherulite-like phase having an optically negative sign. These suspended liquid crystals showed the iridescent color typical of cholesteric liquid crystals. These colors were found to originate from the difference of the refractive indices of the solvents from those of suspended liquid crystals, the so-called "Christiansen effect", and not from the chiral structure in the liquid crystals.We reported recently that the amorphous powdered Nlauroyl-L-glutamic acid (l-LGA),2 which was soaked into aromatic solvents such as benzene or toluene, showed not only birefringence under a polarized microscope but also a positive

The physicochemical properties of triethanolamine long chain N‐acylglutamates are described. The monotriethanolamine salts were less soluble in water and superior in surface activity, compared with the corresponding ditriethanolamine salts. The monotriethanolamine salt showed weak acidity in an aqueous solution. There were some differences between optically active and racemic N‐acylglutamates, especially in the values of critical micelle concentration.

No abstract

The thermal cyclization of ethyl α-isocyanopropionate (I) was performed to 5-ethoxy-4-methyloxazole (II) as an intermediate for the synthesis of pyridoxine. The similar reaction of several new alkyl esters of α-isocyanocarboxylic acid to the corresponding 5-alkoxy-4-substituted oxazole was also carried out. The reaction products of the thermal cyclization of I were investigated. When the cyclization was carried out at 180°C for 5 hr, the maximum yield of the main product, II, was 20%; unreacted I (30%), ethyl α-cyanopropionate(20%), and dimer of I (5%) were also obtained. The α-hydrogen of ethyl α-isocyanosuccinate (X) can be more easily removed than that of I, so X may be expected to be more readily converted to 5-ethoxy-4-ethoxycarbonylmethyloxazole (XI), which is also an intermediate of pyridoxine. The yield of XI from X did not exceed 30% because of the side reaction.

No abstract

A Z-isomer (4) of 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(methoxyimino)acetic acid, which is the common acyl moiety of clinically useful cephem antibiotics, has been prepared from the aminoisoxazoles through the skeletal rearrangement in several routes. Reaction of 3-amino-5-methoxyisoxazole (7) with alkoxycarbonyl isothiocyanates gave methyl 2-(5-alkoxycarbonylamino-1,2,4-thiadiazol-3-yl)acetates (8), which were converted into the target compound 4 through the reaction of the corresponding keto ester with O-methylhydroxylamime. Compound 4 was prepared similarly from 3-aminoisoxazole (10). Also, O-methylation of 2-hydroxyimino-2-(5-methoxycarbonylamino-1,2,4-thiazol-3-yl)acetate (15) with methyl iodide or dimethyl sulfate in the presence of barium oxide and barium hydroxide octahydrate was found to afford exclusively the desired Z-isomer (14a) of methyl 2-(5-methoxycarbonylamino-1,2,4-thiadiazol-3-yl)-2-(methoxyimino)acetate, which was led to 4.