A general method for the preparation of bis-ureas from bis(o-nitrophenyl) carbonate has been developed. Directional urea synthesis is achieved by sequential amine addition to bis(o-nitrophenyl) carbonate in two steps: in the first step bis(o-nitrophenyl) carbonate is reacted with benzylamine to form benzyl-o-nitrophenyl carbamate; in the second step the carbamate is reacted with a variety of di...

A serine proteinase (ycaB) from the yeast Candida albicans A.T.C.C. 10261 was purified to near homogeneity. The enzyme was almost indistinguishable from yeast proteinase B (EC 3.4.21.48), and an Mr of 30,000 for the proteinase was determined by SDS/polyacrylamide-gel electrophoresis. The initial site of hydrolysis of the oxidized B-chain of insulin, by the purified proteinase, was the Leu-Tyr p...

Condensation OF tetra-U-acetyk-D-glucopyranosyl bromide withpnitrophenyl 4,6-O-benzylidene-/?-D-glucopyranoside followed by appropriate deblocking reactions gives rise to an approximately equimolar mixture of p-nitrophenyl @,ophoroside and pnitrophenyi Plaminarabioside. The two glycosides are readiIy separated and isolated in pure form by cellulose-column chromatography.

A reaction of equimolar equivalents 2-naphthaldehyde (1) and 1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one (2) in ethanolic sodium hydroxide at 20 °C for 4 h gave (E)-1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)-3-(naphthalen-2-yl)prop-2-en-1-one (3) 92% yield. Nuclear magnetic resonance spectroscopy single-crystal X-ray diffraction were used to establish the structure...

The kinetics of the acylation of alpha-chymotrypsin by a series of substituted phenyl p-nitrobenzoates have been studied by stopped flow and conventional spectrophotometry. Electron withdrawal in the leaving group accelerates the rate of acylation, and the p value obtained for eight esters is +1.96. The pH- and pD-independent acylation rate constants are, respectively, 1.40 X 10(4) M-1S-1 and 1...

The structures of five of the possible six isomers of (E,E)-1,4-bis(nitrophenyl)-2,3-diaza-1,3-butadiene are reported, including two polymorphs of one of the isomers. (E,E)-1,4-Bis(2-nitrophenyl)-2,3-diaza-1,3-butadiene, C(14)H(10)N(4)O(4) (I), crystallizes in two polymorphic forms (Ia) and (Ib) in which the molecules lie across centres of inversion in space groups P2(1)/n and P2(1)/c, respecti...

Incubation of sheep liver cytoplasmic aldehyde dehydrogenase with the substrate 4-nitrophenyl [14C]acetate in the presence of NADH leads to the formation of 14C-labelled acetaldehyde. This observation strongly supports the idea that the esterase and dehydrogenase activities of the enzyme occur at the same site and involve the intermediacy of a common acyl-enzyme.

The crystal structure of the title compound, K+.C6H4NO6S-, is built up from p-nitrophenyl sulfate anions and potassium cations. Adjacent anions form dimers, which are linked together in a three-dimensional network via short C-H...O contacts. The coordination sphere of the K+ ions may be described as a distorted square antiprism. The crystal structure is further stabilized by pi-pi stacking inte...

The single crystal X-ray structure of new 1,1’-bis(2-nitrophenyl)-5,5’-diisopropyl-3,3’-bipyrazole, 1, is triclinic P I–, a = 7.7113(8), b 12.3926(14), c 12.9886(12) Å, α 92.008(8), β 102.251(8), γ 99.655(9)°. structural arrangement compared to that 5,5’-diisopropyl-3,3’-bipyrazole, 5, whose found tetragonal I41/a, 11.684(1), 19.158(1) Å. comparison also extended the structures previously deter...