TRANS-3,5-DISUBSTITUTEDPYRROLIDINE: ORGANOCATALYST FOR anti-MANNICH REACTIONS
申请人:Tanaka Fujie
公开号:US20070117986A1
公开(公告)日:2007-05-24
A compound of Formula I is disclosed, in which R is a substituent containing a hydrogen bond-forming atom within three atoms from the ring carbon to which the substituent is bonded; X is CH
2
, O, S or NR
1
, wherein R
1
is a hydrocarbyl group or an amino-protecting group having one to about 18 carbon atoms; R
2
is hydrido or a hydrocarbyl group containing one to about twelve carbon atoms; and R
3
is hydrido or methyl, but both R
2
and R
3
are not hydrido when X is CH
2
A molecule of Formula I and those in which R
2
and R
3
can both be hydrido (Formula X) functions as a catalyst in a Mannich reaction to asymmetrically form β-aminoaldehyde or β-aminoketone diastereomeric products having two chiral centers on adjacent carbon atoms and in which the anti-diastereomers are in excess over the syn-diastereomers. Methods for carrying out those syntheses are also disclosed.
Asymmetric Aza-Wacker-Type Cyclization of <i>N</i>-Ts Hydrazine-Tethered Tetrasubstituted Olefins: Synthesis of Pyrazolines Bearing One Quaternary or Two Vicinal Stereocenters
aza-Wacker-type cyclization of N-Ts hydrazine-tethered tetrasubstituted olefins, affording optically active pyrazolines bearing chiral tetrasubstituted carbon stereocenters. This reaction is tolerant to a broad range of substrates under mild reaction conditions, giving the desired chiral products with high enantioselectivities. Generation of two vicinal stereocenters on the C═C double bonds was also achieved
Tetrazole derivatives, and anti-ulcer composition containing the same
申请人:Otsuka Pharmaceutical Company, Limited
公开号:US04372953A1
公开(公告)日:1983-02-08
Tetrazole derivatives of the formula: ##STR1## wherein R.sup.1 is a lower alkykl, phenyl or a group of the formula: --S(O).sub.l --A--(X).sub.m --R.sup.3, and R.sup.2 is hydrogen, a lower alkyl, phenyl or a cycloalkyl when R.sup.1 is the group --S(O).sub.l --A--(X).sub.m --R.sup.3, or R.sup.2 is a group of the formula: --B--CO--R.sup.4 when R.sup.1 is a lower alkyl or phenyl and a pharmaceutically acceptable salt thereof, which have prophylactic or therapeutic activities against peptic and/or duodenal ulcers and are useful as an anti-ulcer drug; processes for the preparation of the tetrazole derivatives; and pharmaceutical composition containing said tetrazole derivatives.
When Ethyl Is Infinitely Different from Methyl: Double Addition of Lithiated Dithianes to Aromatic Carboxylates Revisited
作者:Roman A. Valiulin、Rudresha Kottani、Andrei G. Kutateladze
DOI:10.1021/jo060780f
日期:2006.6.1
benzoate does not produce the expected product of double addition, α,α-bis(alkyldithianyl) benzyl alcohol, for alkyls larger than methyl. Instead, the first step intermediate, i.e. 2-benzoylated dithiane, undergoes an electron-transfer reduction by the second molecule of the dithianyl anion. This reduction is followed by the ring-opening mesolytic fragmentation of the dithiane ring in the ketyl anion radical
A Simple and Convenient Catalytic Procedure for the Preparation of Dithioacetals
作者:Andrew E. Graham
DOI:10.1080/00397919908085819
日期:1999.2
Abstract A simpleprocedure for the synthesis of cyclic and acyclic thioacetals from aldehydes is described which employs hydrogen chloride solutions generated from acetyl chloride and methanol. It was observed that the reaction could be carried out using catalytic quantities of acetyl chloride, potentially allowing acid sensitive substrates to be used under these conditions.