Thieno [2, 3-d] Pyrimidine-4-Ones. Part 4.* Directions of Reactions of the 2-Oxo-, -Thioxo-5, 6-Dimethyl-3, 4-Dihydrothieno [2, 3-d] Pyrimidine-4-Ones with Electrophilic Reagents
I. S. Ortikov
Organic Synthesis Department, Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent 100170, Uzbekistan
B. Zh. Elmuradov *
Organic Synthesis Department, Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent 100170, Uzbekistan
Kh. M. Shakhidoyatov
Organic Synthesis Department, Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent 100170, Uzbekistan
*Author to whom correspondence should be addressed.
Abstract
Interaction of 5,6-dimethyl-3,4-dihydrothieno[2,3-d]pyrimidine-4-one (1), -thione(2) with alkylation agents (methyl-, ethyl-, n-propyl-, n-butyl iodides, allylbromide, benzyl chloride) in different conditions (in the presence of catalyst and/or without catalyst) were investigated. It was shown that methyl group in position 5 under action of nitrating mixture (NM) takes place aromatic ipso-substitution reaction or its oxidation up to corresponding carboxylic acid. Directions of reactions depend on nature of substituent in position N-3. It is revealed, that at absence of the substituent in position 3 (compounds 1, 2, 11) the electrophilic ipso-substitution of methyl group by nitro group with formation of 5-nitroderivatives took place. It is found, that at interaction of compounds 3, 19 with NM instead of substitution of methyl groups at C-5 go in an expected direction, i.e. there are oxidation of methyl groups.
Keywords: Thieno [2, 3-d] pyrimidine-4-ones, alkylation, nitrating mixture, electrophilic ipso-substitution, oxidation