A convenient and efficient method for the synthesis of benzo- and naphthothiazolediones

A series of benzo- and naphthothiazolediones have been synthesized by the reactions of N-substituted thioureas with π-deficient quinones. The products were obtained by the reaction of N-aroylphenylthioureas with 2,3,5,6-tetracholoro-1,4-benzoquinone, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and 2,3-dichloro-1,4-naphthoquinone.     

A rapid method for the determination oftrans unsaturation in fats and derivatives

Thetrans unsaturation present in samples of unsaturated fats and derivatives may be determined from measurement of the infrared absorbance at two wavelengths, one due totrans configuration of a double bond and the other due to the ester or acid group. The ratio of the two absorbance values has a linear relationship with thetrans unsaturation content. Thus, a drop of sample is diluted with CS₂ and the infrared absorbance measured at 10.36 μ and at 8.5–8.6 μ if esters and 10.7 μ if acids. To calculate the per cent isolatedtrans double bonds in the sample, the ratio of the two absorbance values is substituted into the linear equation which was developed from known samples. The method is rapid since the sample need not be weighed nor made up to a known volume and thus may be applied to samples such as those collected from a gas chromatograph or after thin layer chromatography. Presented at the AOCS Meeting, New York, October 1968.     

A method for the determination of the extent of polymerization in frying fats and in fats extracted from fried foods

A method is described for the isolation of polymerized products in frying fats as a urea non-inclusion fraction (NAF). Analysis of fats used in commercial frying operations and of fats extracted from some fried foods is reported. Amount of NAF obtained by the method appears to be in direct relation to the duration of heating. Oils heated at 200C for 24 hr yield 15–18% of NAF having molecular weights of 500–550. Some of the fats extracted from fried foods yielded up to 2.5% of the polymeric fatty acids.     

A coulometric method for the determination of low peroxide values of fats and oils

The AOCS official method for the determination of peroxide values of fats and oils has been modified to perform more precise analyses, especially in the range of extremely low values (peroxide value <1). In the newly developed method presented here, the final titrimetric step of an iodometric method has been replaced by an electrochemical technique, based upon coulometric reduction of the iodine at an electrode maintained at a controlled potential. Using this method peroxide values down to 0.06 were determined with reasonable precision. Finally, the influence of different parameters on the peroxide value obtained was investigated.     

A modified method for the determination of monoglyceride in fats and oils by oxidation with periodic acid

The original periodic acid method of Pohleet al. has been modified to render it more suitable for routine control purposes. An attempt was made to minimize the danger of obtaining high estimates when assaying commercial concentrates prepared from mixed glycerides containing C₁₈ saturated and unsaturated fatty acids. The sharpness of the titration endpoint was markedly improved.     

A convenient method for the determination of molecular weight cut-off of ultrafiltration membranes

With the rapid increase of water contamination,membrane separation technology and their corresponding molecular weight cut-off (MWCO) evaluation method become more necessary.In this study,Panax notoginseng saponins was used as a new standard marker to determinate ultrafiltration (UF) membrane MWCOs,series of Millipore membranes were selected as control group to analyze and calculate the relationship between retention rate and MWCOs with exponential or logarithmic equation.A new and convenient method was provided for determining the membrane MWCO by modeling analysis retention rate with MWCOs,and the regression coefficients ≥0.990.The feasibility and practicability of established method was verified by different manufactures' membrane and dextrans.In the detection progress,as the main ingredient of Panax notoginseng saponins,Notoginsenoside R1,Ginsenoside Rg1,Ginsenoside Rb1and Ginsenoside Rd with different surface activity,the MWCO range of UF membranes can be divided into two zones mainly due to the retention rate difference among Notoginsenoside R1,Ginsenoside Rg1,Ginsenoside Rb1 and Ginsenoside Rd.Zone Ⅰ,1000-10000;and Zone Ⅱ,10000-100000.Thus,the new method would be helpful to improve the applicability of UF membrane in separation technology.     

Pancreatic and microbial lipases: A comparison of the interaction of pancreatic colipase with lipases of various origins

Conjugated bile salts inhibit the hydrolysis of triglycerides (TG) by the lipases fromRhizopus arrhizus andGeotrichum candidum. This occurs for detergent concentrations similar to those which suppress the action of mammalian pancreatic lipases upon the same substrates. However, in opposition with what is observed with the latter enzymes, the activity is not restored by the addition of pancreatic colipase. Both pancreatic andR. arrhizus lipases are inactivated at tributyrin/water interface, but only the first enzyme is protected against this surface denaturation by the pancreatic cofactor. These observations suggest that colipases synthesized in mammalian pancreas display specific interaction towards the lipases made by the same organ.     

Rapid method for the quantitative determination of individual tocopherols in oils and fats

Oils and fats are frozen two times from acetone solution at -80 C under protection by ascorbyl palmitate. Tocopherols (T) and tocotrienols (T₃) present in the filtered extract are separated into their homologues by one-dimensional thin layer chromatography on precoated silica gel plates in the n-hexane/ethyl acetate system 92.5:7.5. Complete separation of the positional isomers β-T and γ-T is accomplished as well, whereas β-T₃ and γ-T are assumed to form identical bands. Suitable spray- and detection systems including new found coloring ones are described for the qualitative estimation of the chromatograms. The content of individual tocopherols (T and T₃) of 24 commercial vegetable oils is quantitatively determined using the Emmerie-Engel procedure.     

Caloric availability and digestibility of new-type fats

Digestibility and caloric availability of new-type fats were determined by feeding these products to young rats while on a restricted caloric intake. Amylose stearate, amylose palmitate, amylose oleate, distearin adipate, and glycerol adipate were low in both categories. Diolein fumarate was completely digested but poorly utilized. These materials were compared with common oils and fatty acids. These new-type fats have potential use as pan greases and surface coatings for foods. Laboratories of the W. & So. Utiliz. Res. & Dev. Div., ARS, U.S.D.A.     

N-乙酰氨基葡萄糖合成方法的改进

改进了N－乙酰氨基葡萄糖的合成方法，后处理过程简单，产率提高至96．7％。     

Simplified method for the determination oftrans monoenes in edible fats by TLC-GLC

Several modifications of an established thin-layer chromatography-gas-liquid chromatography (TLC-GLC) procedure for quantitatingtrans unsaturated fatty acids in edible fats are presented. These refinements considerably simplify the procedure without affecting accuracy. The modifications include: i) the use of pre-coated silica sheets, dynamically impregnated with Ag⁺, which allow separated bands to be cut off with a pair of scissors; and ii) the use of stearic acid in the deliberately combined saturated andtrans monounsaturated fatty acid methyl ester bands as an (endogenous) internal standard.Trans values thereby obtained agree favorably with the results from the conventional technique.     

A convenient preparative method for mintlactone and isomintlactone

Various 2-(2′-hydroxy-4′-methyl-1′-cyclohexylidene) carboxylic acid lactones were synthesised in good yield from carboxylic acids and 4-methylcyclohexanone. For example, mintlactone ( VI ) and isomintlactone ( VII ) were prepared from 2-(1′- hydroxy-4′-methylcyclohexan-1′-yl) propanoic acid ( III ) which was obtained by reaction of propanoic acid ( I ) with 4-methylcyclohexanone ( II ) using lithium naphthalenide in the presence of diethylamine. Compound ( VI ) could be separated from compound ( VII ) by silica gel column chromatography. Several new 2-(2′- hydroxy-4′-methyl-1′-cyclohexylidene) carboxylic acid lactones which may be used as perfumery materials, were obtained in good yield by this method.     

A convenient method for the preparation of asialo-GM1

A convenient and efficient procedure has been devised for the large-scale preparation of asialo-G_M1 from bovine brain gangliosides. The procedure relies on the complete desialylation of brain ganglio-sides, consisting primarily of G_M1, G_D1a, G_D1b and G_T1b, by mild formic acid hydrolysis (0.1 N, 100 C; 2 hr). Following the hydrolysis step, asialo-G_M1 can be isolated and purified by Folch partitioning and Iatrobeads column chromatography, with an overall yield of more than 50%. The ganglioside nomenclature used is that of Svennerholm (1).     

Tetramethylguanidine catalyzed transesterification of fats and oils: A new method for rapid determination of their composition

A new method for the rapid preparation of methyl esters from vegetable oils and fats, using tetramethylguanidine as catalyst, has been developed. This method is compared with the traditional method (Ce 2–66, using 20% BF₃ in methanol) and that proposed by Hartman and Lago (using NH₄Cl/H₂SO₄ in methanol). It is shown that the new method produces the methyl esters in quantitative yields and has certain advantages, as it is simpler, cheaper and does not result in isomerization of the fatty acids.     

A study of the determination of peroxides in fats

Summary The Kokatnur-Jelling method as modified by Lingenfelter for the determination of peroxides in animal fat has been found to agree satisfactorily with other methods now in use. The modified method involves a microtitration in a homogeneous medium (isopropanol) and has the additional advantages of being both simple and rapid. A statistical analysis of the peroxide values shows that the reaction time and temperature and the sample size must be standardized to obtain reproducible and reliable results. Close adherence to reaction specifications such as five minutes at 80°C. or seven minutes at 75°C. is necessary. Three minutes is too short a reaction time. The individual fat sample should contain no more than 50 microequivalents of peroxygen to avoid depression of the peroxide value. This publication is based on one of a series of studies supported largely by the Buffalo Niagara Electric Power Corporation, Carrier Corporation, Central Hudson Gas and Electric Corporation. Central N. Y. Power Corporation, Consolidated Edison Company of N. Y., Inc., Long Island Lighting Company, N. Y. Power and Light Corporation, N. Y. State Electric and Gas Corporation, Rochester Gas and Electric Corporation, and the Staten Island Edison Corporation. The studies are being carried out under the direction of a committee appointed from the staff of Cornell University, consisting of the following members: Dr. L. A. Maynard, chairman, Dean E. Lee Vincent, Dr. C. E. F. Guterman, Dr. A. J. Heinicke, Dean S. C. Hollister. The authors gratefully acknowledge the assistance and interest of Drs. Walter L. Nelson, S. E. Smith, and H. L. Lucas in the experimental design and statistical analysis.     

1,5-萘二硫醇的简便合成

以Zn为催化剂,1,5-萘二磺酸钠、PCI5为原料合成了1,5-萘二硫醇,化合物结构经^1HNMR、IR和元素分析确证。结果表明该合成方法收率高、对环境污染少、适合于工业化生产。     

A convenient method for preparation of monofluorocarboxylic acids

Monofluoro esters were prepared by the reaction of hydroxy esters with N,N-diethyl-1,1,2,3,3,3-hexafluoro propylamine (PPDA). Saponification of these monofluoroesters with enzyme (lipase MY) was attempted to give their corresponding monofluorocarboxylic acids in moderate yields.