Microwave-assisted palladium-catalyzed C–C coupling versus nucleophilic aromatic substitution of hydrogen (SNH) in 5-bromopyrimidine by action of bithiophene and its analogues

Abstract

a b s t r a c t 5-Bromopyrimidine reacts with 2,20 -bithiophene, [2,2 0 :5 0 ,2 00 ]terthiophene and 2-phenylthiophene in the presence of a palladium catalyst to give 5-(het)aryl substituted pyrimidines due to the palladiumcatalyzed arylearyl CeC coupling. However 5-bromo-4-(het)aryl-pyrimidines have been prepared from the same starting materials through the S N H -reaction catalyzed by a Lewis acid. Conditions for both types of reactions were optimized. All components of the reaction mixtures, including by-products, have been elucidated by gaseliquid chromatography/mass-spectrometry. Evidence for the structure of 4-and 5-bithiophenyl-substituted pyrimidines has first been obtained by means of X-ray crystallography analysis. Molecular orbital calculations (TDDFT), as well as the redox and optical measurements for all new compounds have also been performed.

A new route towards dithienoquinazoline and benzo[f]thieno[3,2-h]quinazoline systems using Pd-catalyzed intramolecular cyclization under microwave irradiation

“…For the synthesis of the desired thienoacene derivatives 6a-g the best (so far as we are aware) protocol 26 for direct arylation has been used. The reactions proceed in DMF under microwave irradiation at 180 °C in the presence of mixture 10 mol % of Pd(OAc)2 and 20 mol % PCy3 as catalyst, and 3 equiv of K2CO3 as base.…”

Phosphorylation of C–H bonds of aromatic compounds using metals and metal complexes

“…147 Zhang and co-workers 147 suggested coumarins to be more suitable substrates for the phosphonation because they do not comprise aryl groups in position 2, which created steric hindrance, as opposed to flavones, and they are able to generate stable benzyl radical after addition of the phosphonyl radical at position 3. The reaction of coumarin (81) with diethyl phoshite actually gave 3-phos-phonated coumarin 82a in 65% yield (Scheme 21), which is higher than that for 3-phosphonyl flavone 73a (see Scheme 18). The outcomes of the reaction for a number of coumarins attest that substituents both in the benzene ring and in position 4 have no substantial effect on the product yield.…”

Detection of nitroaromatic explosives by new D–π–A sensing fluorophores on the basis of the pyrimidine scaffold

“…As continuation of our previous studies aimed at obtaining of (hetero)arylated bithio-phenes and their analogues as photosensitizers for dye-sensitized solar cells [17,22,23], and being inspired by the results reported by other groups concerning optical materials based on pyrimidinetriphenylamine and pyrimidine-carbazole dyads [24][25][26][27][28], we have focused our attention on using of donor-π-acceptor Electronic supplementary material The online version of this article (doi:10.1007/s00216-016-9501-4) contains supplementary material, which is available to authorized users. organic dyes, bearing pyrimidine fragments, as chemosensors for NACs.…”

“…Organic molecules, bearing both electron-donating and electron-withdrawing fragments, for instance pyrimidinethiophene conjugated monomers and polymers, have received a considerable attention due to their promising optical and electronic properties [17]. Therefore, a search of routes to novel (hetero)arylated bithiophenes is an important task for organic and organometallic chemistry [18].…”