Reactions of isomeric methyl ethers (2a) and (3a) of triacetic lactone (1) with phosphorus pentasulphide have been found to yield the thiiderivative (2b) and (4a) respectively. Using aqueous solutions of secondary arnines the methyl ether (2a) and its thioanalogue (2b) have been converted into 4-substituted 6-methyl-2H-pyrm-2-ones (2d-O and 2H-pyran-2-thiones (2g-i) respectively. The 2H-pyrqn-2-tiones (2g-l) were isomerised into thiopyrm-2-ones (2j-1). In all these reactions the nucleophillic attack occurs at the 4 or 4,2-positions of the ethers. Thiopyrarn-2-ones (2j-l) on treatment with phosphorus pentasulphide gave the corresponding thio pyram- 2-thiones (2m-o). The spectroscopic data of the compounds are recorded.
P F G PRAILL ,M SIDDIQ ,A W KHAN ,
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