One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones
摘要:
[GRAPHICS]The one-pot cyclization of dilithiated oximes with epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.
One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones
摘要:
[GRAPHICS]The one-pot cyclization of dilithiated oximes with epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.
Compounds of the invention are useful in inhibiting thrombin and treating blood coagulation and cardiovascular disorders and have the following structure:
1
wherein
R
3
is hydrogen or halogen, and u is N or CH.
该发明的化合物在抑制凝血酶、治疗血液凝固和心血管疾病方面具有用处,并具有以下结构:
1
其中
R
3
为氢或卤素,u为N或CH。
One-pot synthesis of pyrazole-5-carboxylates by cyclization of hydrazone 1,4-dianions with diethyl oxalate
作者:Tuan Thanh Dang、Tung Thanh Dang、Peter Langer
DOI:10.1016/j.tetlet.2007.03.093
日期:2007.5
The cyclization of hydrazone dianions with diethyl oxalate afforded pyrazole-5-carboxylates.