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[(1,3‐Dioxolan‐2‐yliden)methyl]phosphonate und ‐phosphinate als (einfache) Synthone in der Heterocyclensynthese
Author(s) -
Neidlein Richard,
Eichinger Thomas
Publication year - 1992
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19920750109
Subject(s) - chemistry , ketene , synthon , phosphinate , oxazolidine , yield (engineering) , medicinal chemistry , phosphonate , organic chemistry , stereochemistry , materials science , fire retardant , metallurgy
[(1,3‐Dioxolan‐2‐ylidene)methyl]phosphonates and ‐phosphinates as [ simple ] Synthons in Heterocyclic Synthesis The readily available [(1,3‐dioxolane‐2‐ylidene)methyl]phosphonates and ‐phosphinates 2a–f ( Scheme 1 ) can be transformed with amines to aliphatic ketene N,O‐and N,N‐acetales (see Scheme 2 , 2a → 3–7 ). Alkanediamines yield with 2a–f the imidazolidines 8a–f and the hexahydropyrimidines 9a–d ( Scheme 3 ). the oxazolidine derivatives 10a–e and the thiazolidine 11 are accessible under special reaction conditions starting from 2a, b ( Scheme 4 ). Hydrazines react with the CN‐group‐containing ketene O,O‐acetals 2a–c to the pyrazoles 12a–g , whereof 12a, d, e can be cyclized to pyrazolo[1,5‐ a ]pyrimidines 13a–d ( Scheme 5 ). Amidines as starting materials transform 2a–c in an analogous way to the pyrimidine derivatives 14a–c ( Scheme 6 ).