During a series of alkylation reactions on Merrifield resin involving a number of alkoxides, generated in situ by the treatment of alcohols with a variety of bases (NaH, LiHMDS, etc.), it was determined that treatment of the resin with a number of hexamethyldisilazide bases gave rise to high yields of aminomethyl resin, presumably by nucleophilic displacement of the chloride. The reaction was optimised as a simple one-step process for the generation of aminomethyl resin from chloromethyl polystyrene. The resulting resin was used to synthesise a tripeptide.

Aggregation due to hydrogen-bonded interchain association is thought to be the cause of difficult sequences in solid-phase peptide synthesis. Hmb (2-hydroxy-4-methoxybenzyl) was introduced recently as a backbone-protecting group for Fmoc/tBu strategies which inhibits this association. Hmb derivatives of four amino acids are now available commercially. This paper describes the syntheses of two difficult sequences which were achieved by judicious use of the Hmb protecting group. (Hmb)Gly, which is attractive because of the ease of coupling the following residue, did not always produce the expected long-range effect. Moving the Hmb protection to a suitable preceding position in the sequence overcame this shortcoming.

The synthesis of 2 non-cross-reacting 3-(substituted-phenyl)-azo-4-hydroxyphenylisothiocyanates is described. These compounds are designed as alternatives to the corresponding hydroxybenzimidates for use in hapten-sandwich double labelling of cell surfaces. The new reagents rapidly and controllably haptenate immunoglobulin and other biological carrier molecules. Haptenated immunoglobulins present the appropriate hapten determinant with little concomitant loss of antigen binding activity.

(R)-(−)-benoxaprofen is stereospecifically inverted to the (S)-( + )-enantiomer by rats and humans. The rate of inversion is much faster in rats (t1/2ca. 2.5 h) than in humans (t1/2 108 h). Inversion in rats apparently does not occur in the liver, but can be brought about in vitro by an everted intestinal sac preparation, suggesting that the transformation takes place while passing through the gut wall.

AbstractDie säurekatalysierte Kondensation des Imins (I) mit den Hydroxyiminoketonen (II) führt zu den Titelverbindungen (III).

The acid-catalysed condensation of diphenylmethyleneamines with various α-hydroxyimino-ketones (1a–f) gave 2,2-diphenyl-2H-imidazole 1-oxides [(2a–f), and (8)]. These compounds react as nitrones with lithium aluminium hydride, methylmagnesium iodide, and dimethyl acetylenedicarboxylate. However, the reaction of 4-methyl-2,2-diphenyl- and 2,2,4-triphenyl-2H-imidazole 1 -oxides with sodium borohydride gave the corresponding 2H-imidazoles. Curtis rearrangement of 5-methyl-2,2-diphenyl-2H-imidazole-4-carbonyl azide 3-oxide (6) gave 7-methyl-5,5-diphenylimidazo[1,5-b][1,2,4]oxadiazol-2(5H)-one (14).