Oxadiazole aniline

They have not been isolated but immediately transformed into N-phenyl-amino-oxadiazoles by treating with aniline. 

Chloro-7-nitrobenz-2,l,3-oxadiazole (NBD-C1) reacts with primary and secondary aliphatic amines to produce intensely fluorescent derivatives. Although anilines, phenols and thiols react with NBD-C1, they produce derivatives which do not fluoresce or which are only weakly fluorescent. This limits the types of compounds which can be analyzed with this reagent and thus makes the technique more selective. This selectivity is desirable in trace analysis because of a lower degree of interference from co-extractives. The general reaction scheme for formation of the fluorescent amine derivatives is shown in Fig.4.50. 

Amino derivatives of isoxazole, 1,3,4-oxadiazole, thiazole, 1,2,4-thiadiazole and 1,3,4-thiadiazole containing the amino group as part of a partial amidine structure react with trichloromethanesulfenyl chloride to give isolable trichloromethanesulfenamides which react with substituted anilines to yield fused thiadiazoles of general structure shown in equation (9). The method has been used to prepare 3H-isoxazolo[3,2-c]-, 3H-thiadiazolo[2,3-c]-, 3H- l,3,4-thiadiazolo[2,3-c]- and 3//-[l,2,4]thiadiazolo[4,3-d]-[l,2,4]thiadiazoles, as well as 3//-[l,2,4]thiadiazolo[3,4-6][ 1,3,4]oxadiazoles (75JOC2600). 

The more reactive 5-substituted 3-arylformamidino-l,2,4-oxadiazoles (65) were rearranged to 3-acylamino-l,2,4-triazoles (66) both by melting and by the action of sodium hydroxide in ethanol at 20°C. The same ring transformation is achieved by heating the 3-ethoxyformylamino-l,2,4-oxa-diazoles (67) with anilines.52... 

Bifunctional systems form heterocyclic rings for example (194) yields (195). Photolysis of N-(triphenylmethyl)anilines results exclusively in C-N bond homolysis to give the trityl (< ) = 0.6-0.8) and anilino radicals." Reduction of the N-O bond cleaved intermediate (196) (formed on irradiation of 5-amino or 5-phenyl-1,2,4-oxadiazoles) by sodium hydrogen sulfide, thiols or thioamides yields the corresponding benzamidines (197). In contrast, in the presence of nucleophilic thioureas (199) or thiocarbamates (200), N-S bond formation occurs and subsequent elimination from the possible intermediate (201) yields the thiadia-zoles (198) or (202) respectively. ... 

When one of the N—H bonds of primary amines is used for arene formation, the other N—H bond can serve as another reaction site for further elaboration. For example, IV-unsubstituted 2-alkynylaniline derivatives 309 undergo a copper-catalyzed direct C—H/N—H coupling with azoles 310 followed by cycloisomerization to form A -azoylindoles 311 in good yields (Scheme 19.83) [153]. Oxadiazoles, benzoxa-zoles, and benzothiazoles can be used as the azole 310 for the reaction. Double hydroamination reaction of the anilines of type 309 with terminal alkynes leading to A -vinylindoles was reported by Zhang et al. [154]. 

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