Nitrile Products Research Articles

Synthesis of 11C‐labeled aromatics using aryl‐chromium tricarbonyl intermediates

Stable and 11C-arylnitriles have been synthesized in 10 minutes by treatment of substituted fluoroaryl (R=H, p-Me, o-Me, p-Cl) chromium tricarbonyl complexes with stable and 11C-cyanide in DMSO at 115°–135°. Under the conditions used, decomplexation of the new complex occurs during the substitution reaction liberating the aryl nitrile product without need for the usual oxidative decomplexation step.

Transition–metal mediated asymmetric synthesis. Part 6. Organometallic approaches to the enantiomer synthesis of tridachione: a role for planar chirality in synthesis design

Two series of complexes which contain planar chirality have been examined as intermediates for the synthesis of tridachione. Alkylation of tricarbonyl(η5-2-methoxy-3,5-dimethylcyclohexadienyl)iron(1+) hexafluorophosphate(1–) with trimethylsilyl cyanide and reaction of the nitrile product with ethyl-lithium afforded an acyl-substituted intermediate for the synthesis of tridachione. Complexation of 1-methoxy-2,4-dimethylbenzene by Mn(CO)3+ gave a complex that was alkylated by vinyl Grignard reagents at the correct position to introduce the 1-methylpropenyl group in tridachione. Methylmagnesium bromide gave predominantly an unexpected regioisomer. These products were converted into Mn(CO)2NO+ dienyl complexes. The influence of the use of planar chirality on the design of synthetic strategies is discussed.

A Breakthrough Time Comparison of Nitrile and Neoprene Glove Materials Produced by Different Glove Manufacturers

Specimens of similar nominal thickness from commercially available nitrile and neoprene gloves were each tested for breakthrough time against three chemicals. The null hypothesis was that the breakthrough times for the glove specimens of the same generic type but produced by different manufacturers would be the same. Breakthrough time data for each material/chemical combination were analyzed using an analysis of covariance to adjust for differences in the measured specimen thickness while testing for product differences. A significant difference in chemical breakthrough times was found among generically similar products produced by different manufacturers. The largest difference between the mean breakthrough time of two generically equivalent products, 30 vs. 300 min, was obtained for perchloroethylene through nitrile products. In conclusion, breakthrough time data for use in selection of chemical protective clothing or in prediction modeling for chemical protective clothing should be manufacturer and product specific.

A note on the enzymic action and biosynthesis of a nitrile‐hydratase from a Brevibacterium sp.

The effect of different compounds on the enzymic action of the nitrile‐hydratase used for the bioconversion of nitriles was studied. An excess of acrylonitrile as a substrate was shown to inhibit the activity of the enzyme. This inhibition occurred only at relatively high substrate concentrations (0.2 mol/l or more). The nitrile bioconversion products (acrylamide, propionamide) and their structural analogues (acrylic acid, thioacetamide) were shown to inhibit the enzyme competitively. The most important inhibition found was that of cyanide (Ki= 0.004 mol/l), a break down product of some nitriles. By using an acetamidase‐negative mutant, amides were shown to inhibit biosynthesis of nitrile‐hydratase. An identical result was obtained with thioacetamide, a non‐substrate compound for acetamidase. This compound repressed the biosynthesis of nitrile‐hydratase by both the wild type and the acetamidase‐negative mutant to the same extent.

Some glucosinolates of Farsetia aegyptia and Farsetia ramosissima

Air-dried leaves of Farsetia aegyptia and F. ramosissima have been analysed for their glucosinolates; the former was shown to contain at least six but chiefly allylglucosinolate, whilst the latter contains at least five but mainly but-3-enylglucosinolate with some 4-(methylthio)butylglucosinolate. Without the addition of extraneous thioglucosidase enzyme, both species gave predominantly nitrile degradation products of glucosinolates; but if extra enzyme were added, corresponding isothiocyanates became the major products instead. Varying the pH from the natural level for the plant also considerably affected the ratios of glucosinolate products.

The formation of Δ 2-pyrrolines by base catalysed nitrile dimerisation

The reaction of (1-bromocyclohexyl)methylidenemalonitrile and 2-bromo-2-methylpropylidenemalonitrile with sodium methoxide in methanoi has been shown to give high yields of Δ 2-pyrrolines in a Thorpe reaction involving two initially formed nitrile products. The by-products formed, (hexahydrobenzaldehyde dimethyl acetal]-1-malonitrile and 1,1-dicyano-2,2-dimethyl-3,3-dimethoxy propane, respectively, were shown to be the only products when the malonitriles were treated with pyridine in methanol. On the action of acid, the Δ 2-pyrrolines aromatised to yield 1,2-dihydro-3H-pyrrolizineproducts. Structure det different reaction paths have been discussed.

A swell graph for nitrile rubber oil-resistant products.

A swell graph for nitrile rubber oil-resistant products.

A swell graph for nitrile rubber oil-resistant products.

A swell graph for nitrile rubber oil-resistant products.