258526-03-3Relevant articles and documents
Synthesis, application and scope of a new protected hydrazine reagent
Maeeorg, Uno,Ragnarsson, Ulf
, p. 681 - 684 (1998)
A novel triprotected hydrazine reagen, 1,2-Boc2-2-Z-hydrazine (3), has been made and investigated with respect to stepwise alkylation/acylation and intermediary deprotection in order to prepare multisubstituted hydrazine derivatives. Alkylation of 3 requires particularly mild basic conditions. Regiospecific cleavage of one Boc-group with acid in monoalkylated product 4 is difficult but can be accomplished with catalytic amounts of Mg(ClO4)2 in MeCN at 50°C in 15 min, furnishing 5 which can easily be alkylated to 6. This product has recently been converted to fully substituted derivatives?.
Synthesis of substituted hydrazines from triprotected precursors
Maeeorg, Uno,Pehk, Tonis,Ragnarsson, Ulf
, p. 1127 - 1133 (2007/10/03)
Full details related to the preparation and application of two triprotected reagents, 1,2,2-Boc3-hydrazine (1) and 1,2-Boc2-2-Z-hydrazine (2), for stepwise synthesis of substituted hydrazines are presented. In the presence of base these compounds undergo substitution at N1, often accompanied by partial loss of protecting groups at N2. Optimized alkylation procedures, eliminating or greatly diminishing these side reactions, involving phase-transfer catalysis are reported. The initial products can be selectively deprotected at N2 to provide a new alkylation site. Twice alkylated derivatives of 1 and 2 differ in their potential to undergo further selective cleavage, and only the latter are capable of such. A limited number of partly protected substituted hydrazine derivatives have been made using the novel procedures. Compounds 1 and 2 both exist as mixtures of two conformers which have been assigned, whereas in alkylated derivatives up to four such are present. For two dialkylated compounds all conformers have also been assigned and their relative distribution experimentally determined. The results are in good agreement with those from theoretical calculations.
