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nmr(CCh) r 2.0-2.2 (m, 2, aromatic), 2.4-2.9 (m, 6, aromatic), 8.00 (s, 1, exchangeable with D20, hydroxyl), and 9.20 (s, 9, iert-butyl); mass spectrum m/e (rel intensity) 254 (0.3, parent), 239 (1), 197 (100), 168 (3), and 152 (6).

IllaCH, (^-'-z N=0 III b mg of sodium hydride for 3 hr. That the methylethylnitrosamine (V) produced in this reaction was the result of direct displacement of iodide, rather than carbene insertion, was demonstrated by subjecting dimethylnitrosamine-ífe (VI)6 to these conditions; the isolation of product with a molecular weight of 93 (mass spectrometry) implies that cleavage of the nitrosamine C-D bond preceded the reaction with the alkylating species.

1 -Hydroxy-7-azabenzotriazole (HOAt) and its corresponding uronium and phosphonium salts are shown to be superior to their benzotriazole analogs in solid-phase peptide synthesis, thereby making possible the automated synthesis of peptides containing hindered amino acids.

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