1,3-Dipolar Cycloaddition of Hydrazones with α-Oxo-ketenes: A Three-Component Stereoselective Entry to Pyrazolidinones and an Original Class of Spirooxindoles
prepared efficiently by a three-component reaction involving a 1,3-dipolarcycloaddition of azomethineimines obtained from hydrazones with α-oxo-ketene dipolarophiles generated in situ. The reaction allows the creation of four covalent bonds and two contiguous chiral quaternary centers with excellent diastereoselectivity in a single catalyst/additive-free, highly atom-economical transformation. From a
The reaction of cycloalkanonhydrazones with mercaptoacetic acid. Synthesis of novel<i>N</i>-aminospirothiazolidinones
作者:R. Raji Reddy、D. S. Iyengar、U. T. Bhalerao
DOI:10.1002/jhet.5570220218
日期:1985.3
Cycloalkanone hydrazones undergo condensation with mercaptoaceticacid to give predominantly the spirothiazolidinones. The structures of the products have been established on the basis of physico-chemical data. These compounds have shown promising antibacterial and antifungal activity.
HETEROCYCLIC SYNTHESIS USING NITRILIMINES: PART 3(1). SYNTHESIS OF SUBSTITUTED 1,2,4,5-TETRAZINES AND 1,2,4,5-TETRAAZA-2-PENTENES
作者:Hany M. Dalloul、Peter H. Boyle
DOI:10.1515/hc.2003.9.5.507
日期:2003.1
The reaction of nitrilimines 2a.b with hydrazones of aliphatic ketones 3 (RHNN=CR'R) led to the formation of the cyclocondensation products 1,2,4,5-tetrazines 4a-g when R = CH3, and to acyclic electrophilic addition products 5a-g when R = H, rather than the cyclocondensation tetrazines products 8.
当 R = CH3 时,腈亚胺 2a.b 与脂肪族酮 3 腙 (RHNN=CR'R) 的反应导致环缩合产物 1,2,4,5-四嗪 4a-g 的形成,以及非环状亲电加成当 R = H 时产物 5a-g,而不是环缩合四嗪产物 8。
Production of masked isocyanates particularly masked polyisocyanates
申请人:——
公开号:US20040242833A1
公开(公告)日:2004-12-02
The invention relates to a method for the production of masked (poly)isocyanates using a masking agent with a C═N bond and a labile hydrogen atom on the &agr; atom relative to the nitrogen of the C═N group, characterised in comprising the following steps: a) preparation of a masking agent with a C═N bond and a labile hydrogen atom on the &agr; atom relative to the nitrogen of the C═N group which may be obtained by condensation of an aldehyde or ketone precursor with a nitrogen-containing precursor which has a functional group reactive towards the carbonyl moiety of the aldehyde or ketone, in an aqueous, organic or hydroorganic medium with liberation of water of condensation; b) in situ reaction of the masking agent with a (poly)isocyanate component for masking to give said (poly)isocyanates which are totally or partially masked.