Studies on heterocyclic enaminonitriles. IV. Reaction of ethyl N-(3-cyano-4,5-dihydro-2-thienyl)oxamates with cyanomethylene compounds in the presence of triethylamine.
The reactions of 2-amino-3-cyano-4, 5-dihydrothiophene (Ia) and 2-amino-3-cyano-5-methyl-(or 4-phenyl)-4, 5-dihydrothiophene (Ib or Ic) with dimethyl acetylenedicarboxylate (DMAD) or methyl propiolate in dimethyl sulfoxide (DMSO) or hexamethylphosphoric triamide gave the corresponding dimethyl(or methyl) 2-amino-5-cyano-6, 7-dihydrothiepin-3, 4-dicarboxylate(or 3-carboxylate) (IIa-c or IVa-c). Compounds Ia-c reacted with DMAD in refluxing xylene to give the corresponding dimethyl α-(3-cyano-4, 5-dihydro-2-thienylamino)fumarates (IIIa-c).
Synthesis of dihydrothieno[2,3-<i>b</i>]pyridines based on titanium(IV) chloride-mediated michael reactions of 2-amino-4,5-dihydro-3-thiophenecarbonitriles with α,β-unsaturated ketones
ketones (e.g. methyl vinyl ketone 2 and benzalacetone 3) in the presence of titanium(IV) chloride to give the corresponding Michael adducts 4a-c and 5a-c. Thermal treatment of compounds 4a-c and 5a-c with titanium(IV) chloride caused intramolecular cyclocondensation to yield the corresponding tetrahydrothieno[2,3-b]pyridines 6a-c and 7a-c. Aromatization of 6a-c and 7a-c with potassium tert-butoxide
在氯化钛(IV)的存在下,2-Arnino-4,5-二氢-3-噻吩甲腈1a-c与α,β-不饱和酮(例如甲基乙烯基酮2和苯并丙酮3)反应,得到相应的迈克尔加合物4a -c和5a-c。用氯化钛(IV)热处理化合物4a-c和5a-c引起分子内环缩合,产生相应的四氢噻吩并[2,3 - b ]吡啶6a-c和7a-c。用叔叔钾对6a-c和7a-c进行芳香化回流的叔丁醇中的叔丁醇平稳进行,得到相应的二氢噻吩并[2,3 - b ]吡啶8a-c和9a-c。
[EN] PROCESS FOR THE PREPARATION OF 5-(1-CYANOCYCLOPROPYL)-PYRIDINE-2-CARBOXYLIC ACID ESTERS AMIDES AND NITRILES<br/>[FR] PROCÉDÉ DE PRÉPARATION D'ESTERS AMIDES ET DE NITRILES D'ACIDE 5-(1-CYANOCYCLOPROPYL)-PYRIDINE-2-CARBOXYLIQUE
申请人:SYNGENTA CROP PROTECTION AG
公开号:WO2022074214A1
公开(公告)日:2022-04-14
A process for the preparation of compound of formula I is provided: Formula (I) where R1and R2are as defined in the description.