The absorbance difference measured when angiotensin-converting enzyme (EC 3.4.15.1) hydrolyzes the substrate N-[3-(2-furyl)acryloyl]-L-phenylalanylglycylglycine is the basis for measuring its activity. We show this difference to be instrument dependent, and describe a method for deriving it that is applicable to manual or automated procedures.

An unprecedented cyclopropenation reaction of alkynes catalyzed by ZnCl2 is reported. While Simmons-Smith-type carbenoids failed in the [2 + 1]-cycloaddition with alkynes, the use of enynones as the carbene source enables the preparation of substituted 2-furyl cyclopropene derivatives with remarkable scope.

In the crystal of the title compound, C(15)H(10)N(2)O(3), the molecules are linked together by inter-molecular N-H⋯N hydrogen bonds into chains along the c axis. The crystal structure also shows weak inter-molecular C-H⋯π hydrogen bonds. The three furanyl rings bonded to the imidazole core are not coplanar with the latter; the dihedral angles between the furanyl and imidazole ring planes are 29...

Crystals of the title compound, C(12)H(10)N(4)O(5), were obtained from a condensation reaction of 2,4-dinitro-phenyl-hydrazine and 2-furyl methyl ketone. The mol-ecule displays a nearly planar structure, and the furan ring is slightly twisted by a dihedral angle of 12.62 (6)° with respect to the phenyl-hydrazone plane. The face-to-face separation of 3.287 (7) Å between parallel benzene rings of...