Study on cyclization reactions of heterocyclic compounds bearing ethynyl and formyl groups in close proximity to each other /

The main aims of this investigation were to investigate cyclization reactions of electron–deficient 6–alkynylpyrimidine–5–carbaldehydes and 2–alkynylquinoline–3–carbaldehydes, and electron–rich 2–alkynylindole–3–carbaldehydes and 2–alkynylthiophene–3–carbaldehydes with N–, S–. O–, C– and P–nucleophiles. It was found, that 6–arylethinylpyrimidine–5–carbaldehydes under the treatment with tert–butylamine underwent thermal or microwave–induced cyclization reaction to form pyrido[4,3–d]pyrimidines. A novel and fast synthetic method for preparation of 1,2,3–trisubstituted 1,2–dihydrobenzo[b][1,6]naphthyridines by means of a three–component reaction between 2–alkynylquinoline–3–carbaldehydes, primary amines and C– or P–pronucleophiles was developed. It was showed, that methyl mercaptoacetate was able to trigger a novel benzannulation reaction of the starting materials. Novel, concise and regioselective synthetic methods of 5,7–dihydrofuro[3,4–d]pyrimidine, 5H–pyrano[4,3–d]pyrimidine, 1,3–dihydrofuro[3,4–b]quinolines and 1H–pyrano[4,3–b]quinolines frameworks via regioselective acetalisation/cyclization reactions of 2,4–disubstituted 6–phenylethynylpyrimidine–5–carbaldehydes and 2–alkynylquinoline–3–carbaldehydes were developed. A relatively short and efficient synthesis of 2–(2–oxoethyl)–1H–indole–3–carbaldehydes via tandem 6–endo–dig cyclization from 2–alkynylindole–3–carbaldehydes was developed. It was found that 2–alkynylquinoline–3–carbaldehydes react with dimethylphosphite in basic medium to produce products of the Pudovik reaction. The latter compounds underwent subsequent phosphonate – phosphate rearrangement in basic media. In the case of 2–(pyridin–2–ylethynyl)quinoline–3–carbaldehyde and 2,4–disubstituted–6–arylethynylpyrimidine–5–carbaldehydes, a smooth and regioselective tandem 5–exo–dig cyclization reactions took place.

Grantor dc:publisher

Institutional Repository of Vilnius University

Year dc:date

2012

Author dc:creator

• Bukšnaitienė, Rita,

Contributors dc:contributor

• ČIKOTIENĖ, INGA

• Heterocycles ; cyclization ; ethynyl ; formyl.

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Repository record dc:identifier

https://repository.vu.lt/VU:ELABAETD1947192&prefLang=en_US

OAI identifier oai:identifier

oai:vu.lt:elaba:1947192