185456-32-0Relevant articles and documents
Preparation of Multiply Protected Alkylhydrazine Derivatives by Mitsunobu and PTC Approaches
Brosse, Nicolas,Pinto, Maria-Fatima,Jamart-Gregoire, Brigitte
, p. 4757 - 4764 (2007/10/03)
Alkylation reactions of hydrazine derivatives by Mitsunobu or PTC approaches are described. It has been shown that aminophthalimide derivatives are better acidic partners than their aminoimidodicarbonate (NBoc2) analogues, the presence of the phthaloyl group increasing the acidity of the sole proton and concomitantly reducing steric hindrance. Moreover, N-aminophthalimide derivatives can be efficiently converted into the corresponding N-amino-imidodicarbonates by a three-stage, one-flask procedure under very mild conditions. These procedures can also be efficiently used for the preparation of orthogonally Nα,Nβ -diprotected α-hydrazino esters. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
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.
