John F. K. Wilshire

C-terminal Sequencing: A New Look at the Schlack-Kumpf Thiocyanate Degradation Procedure

Application of the thiocyanate degradation procedure (Schlack and Kumpf 1926) to a peptide or protein (I) converts the C-terminal amino acid into a substituted thiohydantoin derivative (II) which can be subsequently cleaved to give a shortened (by one amino acid) peptide or protein (III) together with the C-terminal amino acid thiohydantoin (IV):

Photoprotection of wool with sulfonated 2-(2′-hydroxyaryl)-2H-benzotriazoles

Abstract A range of phenolic benzotriazolesulfonic acids containing a wide variety of substituents has been synthesized. These compounds protect wool to a significant extent against photo-tendering and, in some cases, against photo-yellowing. The protective effect is dependent on the nature and position of the substituents and is enhanced by (1) locating the sulfonic acid group distant from the hydrogen-bonded phenolic group and (2) placing bulky alkyl groups ortho to this phenolic group. The protective effect of one of the best photostabilizers (II) has been studied in detail and has been found to depend on both the concentration of the photostabilizer and the pH at which it is applied. The photostabilizer (II) also protects dyed wool to some extent against photo-fading as well as against phototendering.

Structural studies of some 1-polymethyleneimino-2,4-dinitrobenzenesand related compounds; crystal structure of 1-(cis-2′,6′-dimethylpiperidin-1′-yl)-2,4-dinitrobenzene

The ultraviolet and 1H n.m.r. spectra of some 1-polymethyleneimino-2,4-dinitrobenzenes and related compounds are discussed. The effect of trifluoroacetic acid on these spectra was also investigated; with 1-azetidinyl-2,4-dinitrobenzene, acid-catalysed ring opening was observed. The solid-state conformation of 1-(cis-2′,6′-dimethylpiperidin-1′-yl)-2,4-dinitrobenzene has been defined by single-crystal X-ray crystallography. Triclinic crystals belong to the space group P–1 with a 8.165(1), b 7.865(1), c 11.148(1) A, α 95.23(1), β 106.00(1), γ 92.63(1)˚ and Z 2. The structure was refined to a final R of 0.048 for the 2222 observed data. In the crystal, the phenyl ring adopts a slight boat conformation, while the amino and o-nitro groups are significantly twisted from the mean plane of the ring.

Fiber-Reactive Polymethine Dyes Containing the N-2,3-Dibromopropionyl and N-Chlorodifluoropyrimidyl Groups

Several fiber reactive basic (polymethine) dyes containing the N-2,3-dibromopropionyl and N-chlorodifluoropyrimidyl groups have been prepared. They had better washfastness and lightfastness on wool than their nonreactive analogues. Attempts were made to prepare related fiber-reactive dyes containing the 2,4-dichloro- s-triazinyl group but the results were unsatisfactory.