A naphthalene benzimidazole-based chemosensor for the colorimetric and on-off fluorescent detection of fluoride ion.

A novel naphthalene benzimidazole (NBI)-based chemosensor (D2) was developed for fluoride ion (F) detection. The absorption spectrum of D2 changed dramatically from yellow to blue in the visible region accompanied with a 225nm red shift of its absorption maximum upon the addition of F in DMSO. D2 also exhibited a fluorescence turn-off response towards the fluoride ion.

1-[(6-Chloro-pyridin-3-yl)meth-yl]-10-nitro-1,2,3,5,6,7,8,9-octa-hydro-5,9-methano-imidazo[1,2-a]azocin-5-ol.

In the title compound, C16H19ClN4O3, the cyclo-hexane ring displays a chair formation and the tetra-hydro-pyridine ring displays an envelope conformation with the methyl-ene C atom as the flap; the imidazolidine ring also displays an envelope conformation with a methyl-ene C atom as the flap. In the crystal, O-H⋯N hydrogen bonds between hy-droxy groups and pyridine rings link inversion-related mol-ecules into dimers. Weak C-H⋯O hydrogen bonds further link the dimers into supra-molecular chains running along the c axis.

1-(2,2-Dimeth-oxy-eth-yl)-8-nitro-1,2,3,5,6,7-hexa-hydro-imidazo[1,2-a]pyridin-5-ol.

In the title compound, C(11)H(19)N(3)O(5), the six-membered ring displays a half-chair conformation and the imidazolidine ring is essentially planar (r.m.s.

1-[(1,3-Dithio-lan-2-yl)meth-yl]-8-nitro-6-propyl-1,2,3,5,6,7-hexa-hydro-imidazo[1,2-c]pyrimidine.

In the title compound, C(13)H(22)N(4)O(2)S(2), the six-membered ring displays a half-chair conformation. The olefin amine unit is close to being coplanar with the imidazolidine ring (r.m.

(E)-1-[(1,3-Dioxan-4-yl)meth-yl]-2-(nitro-methyl-idene)imidazolidine.

In the title compound, C(9)H(15)N(3)O(4), the 1,3-dioxane ring displays a chair conformation and the five-membered ring is close to planar (r.m.s.

1-[(1,3-Dithio-lan-2-yl)meth-yl]-6-methyl-8-nitro-1,2,3,5,6,7-hexa-hydro-imidazo[1,2-c]pyrimidine.

In the title compound, C(11)H(18)N(4)O(2)S(2), the dithiol-ane ring displays an envelope conformation, the tetra-hydro-pyrimidine ring has a conformation that is between half-chair and screw-boat, and the imidazole ring is essentially planar (r.m.s.

(E)-1-(2,2-Dimeth-oxy-eth-yl)-2-(nitro-methyl-idene)imidazolidine.

In the title compound, C(8)H(15)N(3)O(4), the 2-(nitro-methyl-ene)imidazolidine fragment is close to being planar (r.m.s.

1-[(6-Chloro-3-pyrid-yl)meth-yl]-5-eth-oxy-8-nitro-1,2,3,5,6,7-hexa-hydro-imidazo[1,2-a]pyridine.

In the title compound, C(15)H(19)ClN(4)O(3), an active agrochemical possessing insecticidal activity, the dihedral angle between the mean planes passing through the pyridine ring and the five-membered ring is 87.3 (2)°. The fused pyridine ring adopts a twisted sofa conformation.

cis-Nitromethylene neonicotinoids as new nicotinic family: synthesis, structural diversity, and insecticidal evaluation of hexahydroimidazo[1,2-alpha]pyridine.

A series of neonicotinoids analogues of hexahydroimidazo[1,2-alpha]pyridine were modified at 5-, 6-, and 7-positions, and their insecticidal activities were evaluated. Introducing a methyl or ethyl at 7-position increased the insecticidal activities, while other substituents decreased activities. When alkyl substituents were introduced to 7-position, the insecticidal activities against Pea aphids decreased in the order methyl (7a)>ethyl (7b)>n-butyl (7e)>phenyl (7f)>n-propyl (7c)>iso-propyl (7d), p-NO(2)-phenyl (7g).

Synthesis, insecticidal activity, and QSAR of novel nitromethylene neonicotinoids with tetrahydropyridine fixed cis configuration and exo-ring ether modification.

To keep the nitro group in the cis position, a series of nitromethylene neonicotinoids containing a tetrahydropyridine ring with exo-ring ether modifications were designed and synthesized. All of the compounds were characterized and confirmed by 1H NMR, high-resolution mass spectroscopy, elemental analysis, and IR. The bioassay tests showed that some of them exhibited good insecticidal activities against pea aphids.

Syntheses and biological activities of octahydro-1H-cyclopenta[d]pyrimidine derivatives.

Various nitromethylene derivatives were synthesized regioselectively. Compounds 8a-f were obtained by the reaction of 1-((5-chloropyridin-2-yl)methyl)-2-(nitromethylene)-octahydro-1H-cyclopenta[d]-pyrimidine (3) with primary amines and formaldehyde. The synthesized compounds were identified by 1H NMR, HRMS (EI), and IR, and preliminary bioassays indicated that most of them showed moderate insecticidal activities against Aphis craccivora.