(6S, 7S, 10R)- and (6R, 7S, 10R)-7-isopropyl-10-methyl-4-oxo-1,5-dioxaspiro[5.5]undec-2-enes having an electron-withdrawing substituent at the 2-position: synthesis and use in asymmetric Diels–Alder reactions
Chiral spirocyclic dioxinones (S)-(6) and (S)-(7) have been synthesized from (–)-menthone and used in Diels–Alderreactions with cyclopentadiene; remarkable diastereofacial selectivity (isopropyl side) and endo preference observed in these reactionshave offered a new methodology for asymmetricDiels–Alderreactions.
Some novel benzotriazole, benzothiazinone and pyridooxazinone acyclonucleosides containing 4-hydroxybutyl, 4-hydroxybutoxy, 4-iodobutyl, 2-oxopropyl and 2,3-epoxypropoxy groups as a side chain was prepared.
Oxopropylation of 4,5-dihalopyridazin-6-ones with chloroacetone afforded the corresponding 1-(2-oxo-propyl) derivatives. Reaction of title compound with nucleophiles such as amines, alkoxides were investigated. In addition, selective reduction of 3-nitro-1-(2-oxopropyl)pyridazin-6-ones with iron/ammonium chloride in two phase solutions or zinc in acetic acid gave the corresponding 3-amino or 3-hydroxyimino