Action of acrylonitrile on 4-cyano- and 4-carbethoxy pyridazin-3(2H)-ones and their 3-mercapto derivatives. A novel Synthesis of Pyrano and Thiinopyridazines

Reaction of acrylonitrile with 4-cyano-5,6-diphenyl pyridazin-3(2H)-one and 3(2H)-thione derivative ( 1a, b ) at elevated temperature gave 7H-5-amino-6-cyano-3,4-diphenylpyrano and thiino [2,3-c] pyridazines ( 2a, b ), respectively. However, the reaction of 4-carbethoxy pyridazine derivatives ( 1c, d ) with the same reagent, under the same conditions afforded 6H, 7H-6-cyano-3,4-diphenyl-5-oxopyrano ( 3a ) and thiino [2,3-c] pyridazine ( 3b ), respectively. In addition, treatment of ( 1a, c ) and ( 1b, d ) with acrylonitrile ar reflux in alkaline medium give the respective 3-(2′-cyanoethyloxo) ( 7a, c ) and 3-2′-cyanoethylthio ( 7b, d ) pyridazine derivatives. Prolonged alkaline hydrolysis of either ( 1a, c ) or ( 7a, c ) yielded the same product ( 8a ). Also hydrolysis of ( 1b, d ) and ( 7b, d ) afforded one and the same product ( 8b ). The structures of the products were assigned on the basis of satisfactory analytical and spectroscopic data.     

Inhibition of heterocyclic aromatic amine formation in fried ground beef patties by garlic and selected garlic-related sulfur compounds

The effects of garlic and selected organosulfur compounds (diallyl disulfide, dipropyl disulfide, diallyl sulfide, allyl methyl sulfide, allyl mercaptan, cysteine, and cystine) on the formation of heterocyclic aromatic amines (HAAs) in fried ground beef patties were evaluated. Minced garlic cloves (ca. 4.8 to 16.7%, wt/wt) or organosulfur compounds (0.67 mmol) were added directly to ground beef. Patties (100 g) were fried at 225 degrees C (surface temperature) for 10 min per side. Two patties were fried for each replication, and five replicates were analyzed for each treatment. For each replicate, four subsamples were analyzed (two unspiked subsamples for concentration and two spiked subsamples for the recovery of HAA standards). The volatile sulfur compounds significantly (P < 0.05) reduced concentrations of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by reductions of 46 to 81%, while average reductions of 35, 22, and 71%, were achieved with cystine, cysteine, and whole garlic, respectively. The volatile sulfur compounds reduced concentrations of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline by 34 to 67%, while reductions of 25, 19, and 63% (P < 0.05) were achieved with cystine, cysteine, and whole garlic, respectively. These studies confirm that garlic and some organosulfur compounds have the potential to reduce HAA formation incooked beef patties.     

A boundary-element method for elastostatics in a plane region bounded by a smooth curve

The traditional boundary-element method for elastostatics in a plane region bounded by a smooth curve is modified. A circular element is used for which an analytical scheme for the traction problem is derived. It is shown that the construction of the elements of the coefficient matrix reduces to computing a simple integral which has a closed form solution. This leads to higher accuracy of the final results and considerable saving of computational efforts. The procedure is illustrated by some examples and the accuracy of the method as well as its efficiency are compared with those obtained from commonly used numerical techniques.     

ADSORPTION OF ORGANICS FROM A TRUE IN-SITU OIL SHALE RETORT WATER ON ACTIVATED CARBON IN PACKED BEDS

The adsorption of a true in-situ oil shale retort water on activated carbon at 278 and 298 K was studied in batch experiments and in packed beds with continuous liquid flow. The isotherms were nonlinear over the liquid concentration 0 to 875 mg/1. Breakthrough curves were obtained in packed bed experiments as a function of bed length, particle size, and liquid velocity. A differential approach was used to calculate the mass transfer coefficients and the rates of adsorption. Also the breakthrough curves were analyzed to establish the relative importance of the various individual mechanisms that contributed to the overall adsorption process.     

ADSORPTION OF LIGHT HYDROCARBONS ON SPENT SHALE PRODUCED IN A COMBUSTION RETORT

Adsorption isotherms of ethane, propane, and n-butane on two different retorted oil shales were determined gravimetrically at 284.3, 293.7, and 303.2 K. The equilibrium data for these hydrocarbons were correlated with the Langmuir isotherm equation. The equilibrium adsorption data for all the hydrocarbons studied were also correlated by the modified Polanyi potential theory. A single generalized characteristic curve which correlates the equilibrium adsorption data for all three hydrocarbons was obtained by using the ratio of characteristic free energies.     

A comparison of the boundary element and superposition methods

For some time now, the Boundary Integral Equation (BIE) Method or as it is alternately called the Boundary Element Method (BEM) has been hailed as the technique best suited to problems in elasticity and related fields, both for accuracy and efficiency. The authors demonstrate by example that this is not the case. A much simpler and more versatile technique, the Superposition Method (SUP), is introduced and is shown to outperform BEM in both areas. Followed by a discussion of the merits and drawbacks of each method, compact computer programs for both BEM and SUP and numerical results for nine different example problems are presented to support the authors' claim.     

Action of grignard reagents and amines on some N-(Arylmethyleneamino)phthalimides

N-(Arylmethyleneamino)phthalimides ( 2a–c ) carrying an o-substituent in the aryl group were prepared by the reaction of N-aminophthalimide with o-substituted benzaldehydes. The reaction of these compounds with Grignard reagents proceeded either by normal addition to one of the carbonyl groups to give 3a–c or by addition and cleavage to give 4-arylphthalaz-1-ones 5a–c . The steric effect exhibited by either the Grignard reagent or the N-arylmethylene compound was studied. The reaction of N-furfurylideneaminophthalimide ( 2d ) with Grignard reagents was also investigated. N-(Arylmethyleneamino)phthalimides reacted with primary amines to give N,N′-dialkylphthalamides ( 7a and b ) while the reaction with secondary amines gave ( 8a and b ).