TY - JOUR

T1 - Transformation of fluorinated 2-alkynylanilines by various catalytic systems

AU - Politanskaya, Larisa

AU - Petyuk, Maxim

AU - Tretyakov, Evgeny

N1 - The authors thank the Russian Foundation for Basic Research (grant No 19-53-53003) for financial support and the Chemical Service Center SB RAS for spectral and analytical measurements.

PY - 2019/12/1

Y1 - 2019/12/1

N2 - Simple and efficient approaches to the synthesis of fluorinated benzoazaheterocycles with good yields are reported. Firstly a series of polyfluorinated 2-alkynylanilines – the versatile building blocks – was synthesized by the Sonogashira reaction of o-iodoaniline with terminal alkynes. Then the transformations of the obtained 2,3,4-trifluo-6-alkynilanilines in the presence of KOH or PdCl2 in MeCN, and in the presence of monohydrate of p-toluenesulfonic acid (p-TSA•H2O) in MeOH, EtOH or benzene were investigated. It was found that Ph- and n-Bu-containing alkynylanilines by action of PdCl2 in MeCN underwent an intramolecular cyclization reaction to produce the corresponding indoles in high yields. The reaction of KOH with alkynes containing the tertiary alcohol function at the triple bond produced the unsubstituted on the pyrrole ring indole. It was found that fluorinated 2-alkynilanilines can be transformated into indoles, 2-arylketones and 2,3-dihydroquinolines by action of p-TSA•H2O in boiling alcohols, depending on the substituent at the triple bond. The use of benzene as a solvent in the reaction of p-TSA•H2O with polyfluorinated alkynes, bearing an alcohol group resulted in representative series of 2,3-dihydroquinolinones containing a substituents R1 and R2 in the 2nd position of their structure (R = H, H; Me, Me; H, i-Pr; H, Ph).

AB - Simple and efficient approaches to the synthesis of fluorinated benzoazaheterocycles with good yields are reported. Firstly a series of polyfluorinated 2-alkynylanilines – the versatile building blocks – was synthesized by the Sonogashira reaction of o-iodoaniline with terminal alkynes. Then the transformations of the obtained 2,3,4-trifluo-6-alkynilanilines in the presence of KOH or PdCl2 in MeCN, and in the presence of monohydrate of p-toluenesulfonic acid (p-TSA•H2O) in MeOH, EtOH or benzene were investigated. It was found that Ph- and n-Bu-containing alkynylanilines by action of PdCl2 in MeCN underwent an intramolecular cyclization reaction to produce the corresponding indoles in high yields. The reaction of KOH with alkynes containing the tertiary alcohol function at the triple bond produced the unsubstituted on the pyrrole ring indole. It was found that fluorinated 2-alkynilanilines can be transformated into indoles, 2-arylketones and 2,3-dihydroquinolines by action of p-TSA•H2O in boiling alcohols, depending on the substituent at the triple bond. The use of benzene as a solvent in the reaction of p-TSA•H2O with polyfluorinated alkynes, bearing an alcohol group resulted in representative series of 2,3-dihydroquinolinones containing a substituents R1 and R2 in the 2nd position of their structure (R = H, H; Me, Me; H, i-Pr; H, Ph).

KW - 2,3-Dihydroquinolinones

KW - Cross-coupling

KW - Fluorinated alkynes

KW - Fluorinated heterocycles

KW - Triple bond hydration

KW - ALCOHOLS

KW - CYTOTOXICITY EVALUATION

KW - EFFICIENT SYNTHESIS

KW - REGIOSELECTIVE TRANSFORMATION

KW - ALKYNES

KW - CLEAVAGE

KW - HYDRATION

UR - http://www.scopus.com/inward/record.url?scp=85074458188&partnerID=8YFLogxK

U2 - 10.1016/j.jfluchem.2019.109394

DO - 10.1016/j.jfluchem.2019.109394

M3 - Article

AN - SCOPUS:85074458188

VL - 228

JO - Journal of Fluorine Chemistry

JF - Journal of Fluorine Chemistry

SN - 0022-1139

M1 - 109394

ER -