65996-13-6Relevant articles and documents
γ-Functionalization of α,β-Unsaturated Nitrile in Mild Condition: Versatile Synthesis of 4-Aryl-2-Bromopyridines
Sim, Jaeuk,Viji, Mayavan,Rhee, Jeongtae,Jo, Hyeju,Cho, Suk Joon,Park, Yunjeong,Seo, Seung-Yong,Jung, Kwan-Young,Lee, Heesoon,Jung, Jae-Kyung
supporting information, p. 5458 - 5465 (2019/11/13)
This report describes the synthesis of 4-aryl-2-halopyridines via γ-functionalization of α,β-unsaturated nitriles, which were obtained by the HWE reaction with the corresponding ketones. The key features of our methods involve a conjugated γ-enamine formation of α,β-unsaturated nitrile (enamino nitrile), followed by consecutive intramolecular cyclization, resulting in heteroaromatic compounds like 2-halopyridines, α-pyrone, etc.
Orthoamides. L. Contribution to the chemistry of propiolaldehydaminales - Synthesis and transformations to push-pull-substituted buta-1,3-dienes, cyclobutanes, vinylogous amidinium salts and 1,2,3-triazoles
Kiesel, Michael,Haug, Erwin,Kantlehner, Willi
, p. 159 - 170 (2007/10/03)
Tert-butylaminalester 5 reacts with terminal alkynes to give aminals of substituted propiolaldehydes 3c,d. The aminal 3a is accessible from N,N,N′,N′-tetramethylformamidinium chloride (7b) and sodium acetylide. The aminals 3b,c can also be prepared from bis(dimethylamino)acetonitrile 8 and terminal alkynes in the presence of sodium hydride. The nitrile 8 is also useful for the preparation of the bis-aminal of acetylenedialdehyde 6. The aminal 3e can be transaminated by heating with secondary amines to give the aminals 3f-i. The aminals 3a-i react with strong CH2-acidic compounds (pKa between 9 and 14) to give the 1-dialkylamino-1,3-butadienes 10. The isomeric 1-dialkylamino-butadienes 18 can be obtained from the condensation of the CH-acidic cinnamic acid derivatives 19 with dimethylformamidedimethylacetal. CH and NH-acidic compounds as cyanacetamide react with the aminals 3c,e exclusively with the acidic methylene group to produce the enamines 10h,t. The acylformamidine 21 can be obtained from 10t and tert-butylaminalester 5. The pyridone 22 is accessible from the condensation product 10h by thermal cyclization. The pyrido[2,3-d]pyrimidine 26 is formed in the reaction of the 6-amino-uracile 23 with the aminal 3a. In an unexpected reaction the 1,2-bis(cyano-dialkylaminomethylene)-cyclobutanes 28a-d result from the action of trimethylsilylcyanide on the aminals 3e-h. The corresponding reaction with trimethylsilylisothiocyanate affords the vinylogous amidinium thiocyanates 34a,b. In the reaction of trimethylsilylazide and the aminals 3 are produced the 4-(dialkylaminomethylene)-4H-1,2,3-triazoles 38. Johann Ambrosius Barth 1997.
Iminoformylation Reaction of Substituted Crotonnitriles. I. Synthesis of New N,N-Disubstituted 4-Amino-1,1-dicyanobuta-1,3-dienes
Koeckritz, P.,Sattler, R.,Liebscher, J.
, p. 567 - 579 (2007/10/02)
A usefull and efficient method for the synthesis of 4-amino-1,1-dicyanobuta-1,3-dienes 10-20 based on the iminoformylation reaction of crotonnitriles 7-9 with the system triethyl orthoformate/secondary amine in the presence of an acidic catalyst is described.This novel route to the title compounds yields products which are easy to isolate and to purify and also allows to prepare the hitherto unknown N-aryl substituted 4-amino-1,1-dicyanobuta-1,3-dienes.Hence it is advantageous as compared to existing iminoformylation reactions of crotonnitriles using formamide acetals.
