The synthesis of methyl(2S,4R)-4-(benzyloxy)-N-(2,2-dimethyl-2H-azirin-3-yl
)prolinate (10), a novel 2H-azirin-3-amine ('3-amino-2H-azirine'), is descr
ibed (Scheme 1). The reaction of methyl (2S,4R)-N-(20methylpropanoyl)-4-(be
nzyloxy)prolinate (7) with Lawesson reagent gave methyl (2S.4R)-4-(benzylox
y)-N-[2-(methylthio)propanoyl]prolinate (8) and consecutive treatment with
COCL2, 1.4-diazabicyclo[2.2.2]octane (DABCO). and NaN3 led to 10. The use o
f 10 as a building block of the dipeptide Aib-Hyp (Aib = 2-aminoisobutyric
acid, Hyp = (2S,4R)-4-hydorxyproline) is demonstrated by teh syntheses of s
everal model peptides (Scheme 2 and Table). The benzyl protecting group of
the 4-OH function in Hyp in the model peptides has been removed in good yie
lds.