Simulations show that the total volatile basic amines (TVB) from spoiled fish can be sensed by aziridine-functionalized graphene nanomaterials to induce substantial changes in the physical properties.

The first efficient tandem: "bromination-formylationhydrolysis" for the 1,3-transposition of acyclic allylic alcohols 1 and 2 bearing a nitrile and an ester group is reported.While the Baylis-Hillman reaction produces highly functionalized alkenes 1 of types 1 and 2, which have been demonstrated to be versatile and useful intermediates in the synthesis of natural products 2 and biologically active compounds, 3 this methodology is not efficient for the production of the corresponding 3-substituted allylic alcohols 3 and 4 . The latter compounds are important raw materials for the food industry, 4 as well as intermediates for the synthesis of Nuciferol derivatives, 5 sesquiterpenes lactones, 6 and antifungal and antibacterial products. 7 To our knowledge, few preparations of 3 8 or 4 9 (Scheme 1) have been described.A recent publication 10 on the first synthesis of 3-substituted 2-cyanoallylic alcohols 3 based on reduction of 2-cyano-2,3-epoxy esters prompts us to describe our own results. As part of our ongoing work on the synthesis of novel 2-functional allylic alcohols 3 and 4 , we report here a general and convenient method to accomplish the rearrangement of Baylis-Hillman products 1 and 2 to the corresponding primary allylic alcohols 3 and 4 using a threestep reaction sequence (bromination-formylation-hydrolysis). 11 The sequence involves a regiospecific 1,3-allylic transposition of the hydroxy group (Scheme 2).Our methodology is based on the treatment of 2-(hydroxyalkyl)acrylic compounds 1 and 2 with PBr 3 in diethyl ether at 0°C leading respectively to allylic bromides 5 as a mixture of E , Z-isomers in which the E -isomer is strongly predominant (EWG = CN) and exclusively the Zisomer when EWG = CO 2 Et. The stereochemistry of allyl bromides was assigned by comparing 1 H and 13 C NMR spectral data of these molecules reported in literature. 12 Thus, the displacement of bromide using triethylammonium formate (TEAF; 2 Et 3 N-5 HCO 2 H) as formylating reagent 13 , has been carried out in refluxing acetonitrile. The formyloxy nitriles and esters 6 are hydrolyzed to the corresponding alcohols 3a-g and 4a-h upon hydrolysis in the presence of one drop of concentrated hydrochloric acid at room temperature. 2-(Hydroxymethyl)alk-2-enenitriles 3a-g and ethyl 2-(hydroxymethyl)alk-2-enoates 4a-h prepared are summarized in Table 1.The E -and Z -structure is determined from spectroscopic data 4, 5, 10, 14 of the functional allylic alcohols 3 and 4 and by comparison with data of various authentic samples. 15From Table 1, it is clear that the stereochemistry of the formylation reaction is dependent on the nature of electron-withdrawing group. With EWG = CN, the stereoselectivity of the new allylic alcohols 3a-g seems to depend both on steric and electronic effects and gives E -functional olefins for an electron-withdrawing group (R = p -CF 3 C 6 H 4 ). In contrast, the transformation of secondary alcohols 2 into the corresponding primary alcohols 4a-h is highly stereoselective, independent of the nature of the R group and lea...