To efficiently obtain the subject compound, useful, e.g. as an intermediate for producing an X-ray contrast medium, antitumor medicine, antimicrobial medicine or the like, by reacting cis-2-butene-1,4-diol with a specific carbonyl compound at normal temperature in the presence of an acid catalyst.
This compound is obtained efficiently at low cost by reacting 1mol of cis-2-butene-1,4-diol shown by formula I with 5 to 70 molar equivalents of a carbonyl compound shown by formula II (R1 and R2 are each H or a 1-6C lower alkyl, wherein each of R1 and R2 may contain an unsaturated bond, or they may be bound to each other to form a cyclic structure), e.g. acetone, at normal temperature in the presence of an acid catalyst to produce the objective 4,7-dihydro-1,3-dioxepin shown by formula III, useful, e.g. as an intermediate for producing an X-ray contrast medium, antitumor medicine, antimicrobial medicine or the like.
IGARASHI YOSHIO
MORITA MASAYUKI
SHIMOYAMADA MAKOTO
NAKANO SHIGERU
YOSHIDA MASATAKA
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